From 37d3a1e152707d2da587440c4cea8601b9ef0fd2 Mon Sep 17 00:00:00 2001 From: eunhhu Date: Sun, 27 Sep 2026 13:14:38 +0100 Subject: Lay Pure out as a core with the parts selected around it The app model, the tree store and the HTTP host lived in prototypes/connections among the earlier document runtime, the store was known only by its format's name, and Vega compiled six Pure sources by path. Now, as the README's principle has it: core/ runtime, flow and the app model (module*.c), with what the core asks of storage (state.h, store.h) store/ the tree store (PURETRE3, PUREREC1) serve/ pure-serve: HTTP host, outbound delivery, JSON in place cli/ pure-run, pure-edit-module A top-level make builds libpure.a (app model and store, for hosts to link) and the hosts; make check runs the store's and the app model's tests. The earlier runtime still builds from prototypes/connections against core/ and store/ (check, check-tree and check-core pass). Design 009 records the rule: parts by role behind libraries; git repositories split by coupling, so the store stays here while its contract moves with the core, and Vega stays apart. --- core/module.c | 2122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 2122 insertions(+) create mode 100644 core/module.c (limited to 'core/module.c') diff --git a/core/module.c b/core/module.c new file mode 100644 index 0000000..697e918 --- /dev/null +++ b/core/module.c @@ -0,0 +1,2122 @@ +#include "module.h" +#include "module-save.h" +#include "module-text.h" +#include +#include +#include +#include + +enum { STATE_BYTES = 16, COLLECTION_BYTES = 12, INPUT_BYTES = 16, FIELD_BYTES = 8, + CONSTANT_BYTES = 8, RECORD_BYTES = 8, RECORD_FIELD_BYTES = 16, VIEW_BYTES = 16, + HANDLER_BYTES = 12, OP_BYTES = 16 }; +/* T_FIELD and T_ITEM stand for the type of the message or record field + * named, T_KEY for the type of the named keyed list's key. */ +enum { T_NUM = 1, T_BYTES = 2, T_TEXT = 3, T_CURSOR = 4, T_FIELD = 5, T_INDEX = 6, T_ITEM = 7, T_KEY = 8 }; +enum { FROM_PAYLOAD, FROM_DOCUMENT, FROM_COPY, FROM_CONSTANT, FROM_TEXT, FROM_ARENA }; +/* Where an opcode may appear. */ +enum { IN_VIEW = 1, IN_HANDLER = 2, IN_MESSAGE = 4, IN_KEYED = 8, IN_TEXT = 16, IN_ROW = 32 }; +enum { READ = IN_VIEW | IN_HANDLER }; +/* What an argument names: nothing (it is 0), a state of one type (A_STATE + + * the type), a list and one of its record's fields, a message field, the + * collection, a constant, a unit, the column's row, a branch target, a stack + * depth, a fold, a relation or a keyed list. */ +enum { A_NONE, A_STATE, A_ITEM = A_STATE + PURE_STATE_INDEX + 1, A_FIELD, A_COLLECTION, A_CONSTANT, A_UNIT, + A_ROW, A_TARGET, A_DEPTH, A_FOLD, A_RELATION, A_KEYED, A_OUTPUT }; +/* A fold's block is verified as a column that leaves one number (count) or + * two (a value and whether to include it), a table's filter as a column that + * leaves one: these stand for a view type. */ +enum { FOLD_ONE = 100, FOLD_TWO, FILTER }; +/* The text or list an opcode works on: its cursor and index operands belong + * to it, and so does a cursor or index it pushes. O_ANY: no rule. O_OPERAND: + * it pushes a position in its operand's text or list. O_ARG: the argument. + * O_REF: the text or list of the argument's cursor or index state. O_LIST: + * the list of an item argument. */ +enum { O_ANY, O_OPERAND, O_ARG, O_REF, O_LIST }; +static const unsigned char magic[8] = {'P','U','R','E','M','O','D','5'}; + +/* Operand types popped (bottom to top), the type pushed, where allowed, what + * the argument names and the text or list worked on. */ +#define NUMS(pops) {pops, {T_NUM, T_NUM, T_NUM}, T_NUM, READ, A_NONE, O_ANY} +#define STATE(type) A_STATE + PURE_STATE_##type +static const struct { unsigned char pops, in[3], out, where, arg, of; } signature[PURE_OP_COUNT] = { + [PURE_OP_CONST] = NUMS(0), [PURE_OP_ADD] = NUMS(2), [PURE_OP_SUB] = NUMS(2), [PURE_OP_MUL] = NUMS(2), + [PURE_OP_DIV] = NUMS(2), [PURE_OP_NEG] = NUMS(1), [PURE_OP_LT] = NUMS(2), [PURE_OP_LE] = NUMS(2), + [PURE_OP_GT] = NUMS(2), [PURE_OP_GE] = NUMS(2), [PURE_OP_EQ] = NUMS(2), [PURE_OP_NE] = NUMS(2), + [PURE_OP_AND] = NUMS(2), [PURE_OP_OR] = NUMS(2), [PURE_OP_NOT] = NUMS(1), [PURE_OP_MIN] = NUMS(2), + [PURE_OP_MAX] = NUMS(2), [PURE_OP_CLAMP] = NUMS(3), + [PURE_OP_LOAD] = {0, {0}, T_NUM, READ, STATE(NUM), O_ANY}, + [PURE_OP_DT] = {0, {0}, T_NUM, IN_HANDLER, A_NONE, O_ANY}, + [PURE_OP_STORE] = {1, {T_NUM}, 0, IN_HANDLER, STATE(NUM), O_ANY}, + [PURE_OP_JZ] = {1, {T_NUM}, 0, READ, A_TARGET, O_ANY}, + [PURE_OP_JMP] = {0, {0}, 0, READ, A_TARGET, O_ANY}, + [PURE_OP_FIELD] = {0, {0}, T_FIELD, IN_MESSAGE, A_FIELD, O_ANY}, + [PURE_OP_DOC] = {0, {0}, T_BYTES, IN_KEYED, A_COLLECTION, O_ANY}, + [PURE_OP_DOC_SIZE] = {0, {0}, T_NUM, IN_KEYED, A_COLLECTION, O_ANY}, + [PURE_OP_LEN] = {1, {T_BYTES}, T_NUM, IN_HANDLER, A_NONE, O_ANY}, + [PURE_OP_REPLACE] = {3, {T_NUM, T_NUM, T_BYTES}, 0, IN_KEYED, A_COLLECTION, O_ANY}, + [PURE_OP_REPLY] = {1, {T_BYTES}, 0, IN_MESSAGE, A_NONE, O_ANY}, + [PURE_OP_REQUIRE] = {1, {T_NUM}, 0, IN_HANDLER, A_NONE, O_ANY}, + [PURE_OP_TEXT_CONST] = {0, {0}, T_TEXT, READ, A_CONSTANT, O_ANY}, + [PURE_OP_TEXT_LOAD] = {0, {0}, T_TEXT, READ, STATE(TEXT), O_ANY}, + [PURE_OP_TEXT_INPUT] = {0, {0}, T_TEXT, IN_TEXT, A_NONE, O_ANY}, + [PURE_OP_NUM_TEXT] = {1, {T_NUM}, T_TEXT, READ, A_NONE, O_ANY}, + [PURE_OP_CONCAT] = {2, {T_TEXT, T_TEXT}, T_TEXT, READ, A_NONE, O_ANY}, + [PURE_OP_CHARS] = {1, {T_TEXT}, T_NUM, READ, A_NONE, O_ANY}, + [PURE_OP_LINES] = {1, {T_TEXT}, T_NUM, READ, A_NONE, O_ANY}, + [PURE_OP_TEXT_BYTES] = {1, {T_TEXT}, T_NUM, READ, A_NONE, O_ANY}, + [PURE_OP_CUR_LOAD] = {0, {0}, T_CURSOR, READ, STATE(CURSOR), O_REF}, + [PURE_OP_CUR_START] = {0, {0}, T_CURSOR, READ, STATE(TEXT), O_ARG}, + [PURE_OP_CUR_END] = {0, {0}, T_CURSOR, READ, STATE(TEXT), O_ARG}, + [PURE_OP_CUR_MOVE] = {2, {T_CURSOR, T_NUM}, T_CURSOR, READ, A_UNIT, O_OPERAND}, + [PURE_OP_CUR_STORE] = {1, {T_CURSOR}, 0, IN_HANDLER, STATE(CURSOR), O_REF}, + [PURE_OP_TEXT_INSERT] = {2, {T_CURSOR, T_TEXT}, 0, IN_HANDLER, STATE(TEXT), O_ARG}, + [PURE_OP_TEXT_REMOVE] = {2, {T_CURSOR, T_CURSOR}, 0, IN_HANDLER, STATE(TEXT), O_ARG}, + [PURE_OP_TEXT_LINE] = {1, {T_CURSOR}, T_TEXT, READ, STATE(TEXT), O_ARG}, + [PURE_OP_TEXT_SET] = {1, {T_TEXT}, 0, IN_HANDLER, STATE(TEXT), O_ANY}, + [PURE_OP_TEXT_FROM] = {1, {T_BYTES}, T_TEXT, READ, A_NONE, O_ANY}, + [PURE_OP_BYTES_FROM] = {1, {T_TEXT}, T_BYTES, READ, A_NONE, O_ANY}, + [PURE_OP_CUR_COUNT] = {1, {T_CURSOR}, T_NUM, READ, A_UNIT, O_ANY}, + /* Record operations also take as many values as the list's record has fields. */ + [PURE_OP_LIST_COUNT] = {0, {0}, T_NUM, READ, STATE(LIST), O_ANY}, + [PURE_OP_LIST_APPEND] = {0, {0}, 0, IN_HANDLER, STATE(LIST), O_ANY}, + [PURE_OP_LIST_INSERT] = {1, {T_INDEX}, 0, IN_HANDLER, STATE(LIST), O_ARG}, + [PURE_OP_LIST_REMOVE] = {1, {T_INDEX}, 0, IN_HANDLER, STATE(LIST), O_ARG}, + [PURE_OP_ITEM_GET] = {1, {T_INDEX}, T_ITEM, READ, A_ITEM, O_LIST}, + [PURE_OP_ITEM_SET] = {1, {T_INDEX}, 0, IN_HANDLER, A_ITEM, O_LIST}, + [PURE_OP_INDEX_LOAD] = {0, {0}, T_INDEX, READ, STATE(INDEX), O_REF}, + [PURE_OP_INDEX_STORE] = {1, {T_INDEX}, 0, IN_HANDLER, STATE(INDEX), O_REF}, + [PURE_OP_INDEX_MOVE] = {2, {T_INDEX, T_NUM}, T_INDEX, READ, A_NONE, O_OPERAND}, + [PURE_OP_INDEX_FIRST] = {0, {0}, T_INDEX, READ, STATE(LIST), O_ARG}, + [PURE_OP_INDEX_LAST] = {0, {0}, T_INDEX, READ, STATE(LIST), O_ARG}, + [PURE_OP_INDEX_NUM] = {1, {T_INDEX}, T_NUM, READ, A_NONE, O_ANY}, + [PURE_OP_ROW] = {0, {0}, T_INDEX, IN_ROW, A_ROW, O_ARG}, + /* Stack copies: their types come from the values they move. */ + [PURE_OP_PICK] = {0, {0}, 0, READ, A_DEPTH, O_ANY}, + [PURE_OP_SLIDE] = {0, {0}, 0, READ, A_DEPTH, O_ANY}, + [PURE_OP_FOLD] = {0, {0}, T_NUM, READ, A_FOLD, O_ANY}, + [PURE_OP_TEXT_COMPARE] = {2, {T_TEXT, T_TEXT}, T_NUM, READ, A_RELATION, O_ANY}, + [PURE_OP_LIST_FIND] = {1, {T_KEY}, T_INDEX, READ, A_KEYED, O_ARG}, + [PURE_OP_LIST_HAS] = {1, {T_KEY}, T_NUM, READ, A_KEYED, O_ANY}, + [PURE_OP_NOW] = {0, {0}, T_NUM, IN_HANDLER, A_NONE, O_ANY}, + [PURE_OP_SEND] = {0, {0}, 0, IN_HANDLER, A_OUTPUT, O_ANY}, + [PURE_OP_FLOOR] = NUMS(1), [PURE_OP_MOD] = NUMS(2), +}; +#undef NUMS +#undef STATE + +static uint32_t read16(const unsigned char *p) { return (uint32_t)p[0] | (uint32_t)p[1] << 8; } + +static uint32_t read32(const unsigned char *p) { + return (uint32_t)p[0] | (uint32_t)p[1] << 8 | (uint32_t)p[2] << 16 | (uint32_t)p[3] << 24; +} + +static void write32(unsigned char *p, uint32_t value) { + for (unsigned i = 0; i < 4; ++i) p[i] = (unsigned char)(value >> (8 * i)); +} + +static double read_double(const unsigned char *p) { + uint64_t bits = read32(p) | (uint64_t)read32(p + 4) << 32; + double value; + memcpy(&value, &bits, sizeof(value)); + return value; +} + +PURE_COLD static bool key_name(const char *key) { + static const char *const named[] = {"Space", "Enter", "ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown", + "Backspace", "Delete", "Home", "End", "Tab", "Escape", "PageUp", "PageDown"}; + for (size_t i = 0; i < sizeof(named) / sizeof(*named); ++i) + if (!strcmp(key, named[i])) return true; + if (!strncmp(key, "Key", 3)) return key[3] >= 'A' && key[3] <= 'Z' && !key[4]; + if (!strncmp(key, "Digit", 5)) return key[5] >= '0' && key[5] <= '9' && !key[6]; + return false; +} + +/* A document key: 1..64 bytes of [A-Za-z0-9_-], as every Pure store accepts. */ +static bool document_key(const char *key) { + size_t length = key ? strlen(key) : 0; + if (!length || length > 64) return false; + for (size_t i = 0; i < length; ++i) { + char c = key[i]; + if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9') || + c == '-' || c == '_')) return false; + } + return true; +} + +/* Strings are [u8 length][bytes]; a name is 1..31 bytes: an ASCII identifier, + * a path of identifiers joined by dots (a message field inside a group, as + * user.name), or any printable ASCII (a key's name). */ +enum { NAME_IDENTIFIER, NAME_PATH, NAME_PRINTABLE }; +PURE_COLD static bool name_at(const unsigned char *strings, uint32_t size, uint32_t offset, + int kind, char out[PURE_MODULE_NAME]) { + if (offset >= size) return false; + uint32_t length = strings[offset]; + if (!length || length >= PURE_MODULE_NAME || length > size - offset - 1) return false; + for (uint32_t i = 0, start = 0; i < length; ++i) { + unsigned char c = strings[offset + 1 + i]; + bool letter = (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_'; + if (kind == NAME_PATH && c == '.' && i > start && i + 1 < length) { start = i + 1; continue; } + if (!letter && !(i > start && c >= '0' && c <= '9') && (kind != NAME_PRINTABLE || c < 32 || c > 126)) + return false; + } + memcpy(out, strings + offset + 1, length); + out[length] = 0; + return true; +} + +/* The input whose handler this is, or -1 for frame. */ +static int event_input(uint32_t event) { return event ? (int)((event - 1) / 2) : -1; } + +/* The state an argument names must have this type. */ +static bool state_of(const PureModule *m, uint32_t state, uint8_t type) { + return state < m->states && m->state_type[state] == type; +} + +/* The list an item operation names: its low 16 bits (the field is above). */ +static uint32_t list_of(uint32_t arg) { return arg & 0xFFFF; } +static uint32_t item_field(uint32_t arg) { return arg >> 16; } + +static unsigned char field_type(const PureModule *m, uint32_t list, uint32_t field) { + return m->record_field_text[m->record[m->state_ref[list]].first + field] ? T_TEXT : T_NUM; +} + +PURE_COLD static bool names_arg(const PureModule *m, unsigned kind, uint32_t arg, const PureInputShape *shape, int row) { + switch (kind) { + case A_ITEM: + return state_of(m, list_of(arg), PURE_STATE_LIST) && item_field(arg) < m->record[m->state_ref[list_of(arg)]].count; + case A_FIELD: return arg < shape->field_count; + case A_COLLECTION: return arg < m->collections; + case A_CONSTANT: return arg < m->constants; + case A_UNIT: return arg <= PURE_UNIT_LINE; + case A_ROW: return (int)arg == row; + case A_FOLD: return (arg & 0xFF) <= PURE_FOLD_FIRST && state_of(m, arg >> 8 & 0xFF, PURE_STATE_LIST) && arg >> 16; + case A_RELATION: return arg <= PURE_NOT_EQUAL; + case A_KEYED: return state_of(m, arg, PURE_STATE_LIST) && m->state_key[arg]; + case A_OUTPUT: return arg < m->inputs && m->input[arg].kind == PURE_KIND_OUTPUT; + case A_NONE: case A_TARGET: case A_DEPTH: return true; + default: return state_of(m, arg, (uint8_t)(kind - A_STATE)); + } +} + +/* The stack a branch brings to its target, while the target is ahead. */ +typedef struct { uint32_t target; int height; unsigned char types[PURE_MODULE_STACK], owners[PURE_MODULE_STACK]; } Join; + +static bool same_stack(const Join *join, int height, const unsigned char *types, const unsigned char *owners) { + return join->height == height && !memcmp(join->types, types, (size_t)height) && + !memcmp(join->owners, owners, (size_t)height); +} + +/* Types and heights are checked per instruction; a cursor's type records + * which text it belongs to and an index's type which list (other values + * belong to nothing). Branches go forward within the block. Every path into + * a join brings the same stack (types and owners), so a value may cross a + * join, as in a conditional expression; at most 8 joins with a non-empty + * stack are ahead at once. Handlers end empty, views with one value of their + * type. A column (row is its list) may read the row it is evaluated for. + * A fold's block is verified as a column of its list (reads only, no fold + * in it); the block around treats it as one instruction and may not branch + * into it. Returns why the block is refused, with at moved to the + * instruction when one is at fault, or NULL. */ +PURE_COLD static const char *verify_block(const PureModule *, PureBlock, int view, int row, uint32_t event, uint32_t *at); + +/* target marks, per instruction of the block, a branch into it with an empty stack. */ +PURE_COLD static const char *verify_code(const PureModule *m, PureBlock block, int view, int row, uint32_t event, + uint32_t *at, unsigned char *target) { +#define REFUSE(why) do { *at = pc; return why; } while (0) + if (view >= 0 && !block.length) return "empty view"; + int input = view >= 0 ? -1 : event_input(event); + const PureInputShape *shape = input >= 0 ? &m->input[input] : NULL; + unsigned where = view >= 0 ? IN_VIEW | (row >= 0 ? IN_ROW : 0) : IN_HANDLER; + if (shape && shape->kind == PURE_KIND_MESSAGE) where |= IN_MESSAGE | (shape->keyed ? IN_KEYED : 0); + if (shape && shape->kind == PURE_KIND_TEXT) where |= IN_TEXT; + unsigned char types[PURE_MODULE_STACK], owners[PURE_MODULE_STACK]; + Join joins[PURE_MODULE_JOINS]; + unsigned open = 0; + int height = 0; + bool reachable = true; + for (uint32_t i = 0; i <= block.length; ++i) { + uint32_t pc = block.start + i; + /* Branches here brought an empty stack (target) or the stack of a join. */ + unsigned join = open; + for (unsigned k = 0; k < open; ++k) if (joins[k].target == pc) join = k; + if (join < open) { + if (target[i] || (reachable && !same_stack(&joins[join], height, types, owners))) + REFUSE("join with different stacks"); + height = joins[join].height; + memcpy(types, joins[join].types, (size_t)height); + memcpy(owners, joins[join].owners, (size_t)height); + joins[join] = joins[--open]; + reachable = true; + } else if (target[i]) { + if (reachable && height) REFUSE("join with different stacks"); + height = 0; + reachable = true; + } + if (i == block.length) break; + if (!reachable) REFUSE("unreachable instruction"); + const PureOp *op = &m->code[pc]; + if (op->op >= PURE_OP_COUNT) REFUSE("unknown opcode"); + unsigned allowed = signature[op->op].where, kind = signature[op->op].arg, of = signature[op->op].of; + if (!(allowed & where)) { + if (allowed & IN_ROW) REFUSE("row outside a column"); + if (view == FILTER) REFUSE("filter with an effect"); + if (view >= FOLD_ONE) REFUSE("fold with an effect"); + if (view >= 0) REFUSE("view with an effect"); + if (allowed & IN_KEYED) REFUSE("document operation outside a keyed message handler"); + if (allowed & IN_TEXT) REFUSE("text input outside a text handler"); + REFUSE("message operation outside a message handler"); + } + uint32_t arg = op->arg; + if ((kind == A_NONE && arg) || (op->op == PURE_OP_CONST ? !isfinite(op->value) : op->value != 0)) + REFUSE("non-canonical operand"); + if (!names_arg(m, kind, arg, shape, row)) REFUSE("operand names no such state, field, constant or unit"); + /* A keyed list places its items by key, and an item's key stays. */ + if (op->op == PURE_OP_LIST_INSERT && m->state_key[arg]) REFUSE("insert by position into a keyed list"); + if (op->op == PURE_OP_ITEM_SET && m->state_key[list_of(arg)] == item_field(arg) + 1) + REFUSE("change of a keyed list's key"); + /* PICK copies the value arg below the top; SLIDE drops arg values under the top. */ + if (kind == A_DEPTH) { + bool pick = op->op == PURE_OP_PICK; + if (pick ? arg >= (uint32_t)height : !arg || arg >= (uint32_t)height) REFUSE("stack underflow"); + if (pick && height == PURE_MODULE_STACK) REFUSE("stack overflow"); + int from = height - 1 - (int)arg, to = pick ? height++ : from; + types[to] = pick ? types[from] : types[height - 1]; + owners[to] = pick ? owners[from] : owners[height - 1]; + if (!pick) height = from + 1; + continue; + } + uint32_t skip = 0; + if (kind == A_FOLD) { + uint32_t inner = pc; + skip = arg >> 16; + if (view >= FOLD_ONE) REFUSE(view == FILTER ? "fold inside a filter" : "fold inside a fold"); + if (skip > block.length - i - 1) REFUSE("fold block outside its block"); + unsigned how = arg & 0xFF; + const char *why = verify_block(m, (PureBlock){pc + 1, skip}, + how == PURE_FOLD_COUNT || how == PURE_FOLD_FIRST ? FOLD_ONE : FOLD_TWO, + (int)(arg >> 8 & 0xFF), 0, &inner); + if (why) { *at = inner; return why; } + for (uint32_t k = i + 1; k <= i + skip; ++k) { + if (target[k]) REFUSE("branch into a fold"); + for (unsigned j = 0; j < open; ++j) if (joins[j].target == block.start + k) REFUSE("branch into a fold"); + } + } + /* Operand types, bottom to top; record operations take their fields. */ + unsigned char need[PURE_MODULE_FIELDS + 2]; + unsigned pops = signature[op->op].pops; + memcpy(need, signature[op->op].in, sizeof(signature[op->op].in)); + if (op->op == PURE_OP_SEND) { + const PureInputShape *output = &m->input[arg]; + for (unsigned f = 0; f < output->field_count; ++f) { + uint8_t type = m->field[output->field_start + f].type; + need[f] = type == PURE_FIELD_TEXT ? T_TEXT : type == PURE_FIELD_BYTES ? T_BYTES : T_NUM; + } + pops = output->field_count; + } else if (op->op == PURE_OP_LIST_APPEND || op->op == PURE_OP_LIST_INSERT) { + const PureRecord *record = &m->record[m->state_ref[arg]]; + for (unsigned f = 0; f < record->count; ++f) need[pops + f] = field_type(m, arg, f); + pops += record->count; + } else if (op->op == PURE_OP_ITEM_SET) { + need[pops++] = field_type(m, list_of(arg), item_field(arg)); + } else if (need[0] == T_KEY) { + need[0] = field_type(m, arg, m->state_key[arg] - 1u); + } + if (height < (int)pops) REFUSE("stack underflow"); + height -= (int)pops; + for (unsigned k = 0; k < pops; ++k) + if (types[height + (int)k] != need[k]) REFUSE("operand type"); + unsigned owner = of == O_ARG ? arg : of == O_REF ? m->state_ref[arg] : of == O_LIST ? list_of(arg) : 0; + for (unsigned k = 0; of >= O_ARG && k < pops; ++k) { + unsigned char type = types[height + (int)k]; + if ((type == T_CURSOR || type == T_INDEX) && owners[height + (int)k] != owner) + REFUSE(type == T_CURSOR ? "cursor of another text" : "index of another list"); + } + unsigned char out = signature[op->op].out; + if (kind == A_FOLD && (arg & 0xFF) == PURE_FOLD_FIRST) { /* an index of its list */ + out = T_INDEX; + of = O_ARG; + owner = arg >> 8 & 0xFF; + } + if (out == T_FIELD) { + uint8_t type = m->field[shape->field_start + arg].type; + out = type == PURE_FIELD_TEXT ? T_TEXT : type == PURE_FIELD_BYTES ? T_BYTES : T_NUM; + } + if (out == T_ITEM) out = field_type(m, list_of(arg), item_field(arg)); + if (out) { + if (height == PURE_MODULE_STACK) REFUSE("stack overflow"); + owners[height] = (unsigned char)(out != T_CURSOR && out != T_INDEX ? 0 : of == O_OPERAND ? owners[height] : owner); + types[height++] = out; + } + if (kind == A_TARGET) { + if (arg <= pc || arg > block.start + block.length) REFUSE("branch not forward within its block"); + join = open; + for (unsigned k = 0; k < open; ++k) if (joins[k].target == arg) join = k; + if (!height) { + if (join < open) REFUSE("join with different stacks"); + target[arg - block.start] = 1; + } else if (join < open) { + if (!same_stack(&joins[join], height, types, owners)) REFUSE("join with different stacks"); + } else { + if (target[arg - block.start]) REFUSE("join with different stacks"); + if (open == PURE_MODULE_JOINS) REFUSE("more than 8 joins ahead"); + joins[open] = (Join){.target = arg, .height = height}; + memcpy(joins[open].types, types, (size_t)height); + memcpy(joins[open++].owners, owners, (size_t)height); + } + if (op->op == PURE_OP_JMP) reachable = false; + } + i += skip; + } + if (!reachable) return "block end is unreachable"; + if (view == FILTER) return height != 1 || types[0] != T_NUM ? "filter must leave one number" : NULL; + if (view >= FOLD_ONE) { + int want = view - FOLD_ONE + 1; + return height != want || types[0] != T_NUM || types[want - 1] != T_NUM ? "fold block must leave its numbers" : NULL; + } + unsigned char result = view == PURE_VIEW_TEXT ? T_TEXT : T_NUM; + if (view >= 0 ? height != 1 || types[0] != result : height != 0) + return view >= 0 ? "view must leave one value of its type" : "handler must leave no value"; + return NULL; +#undef REFUSE +} + +PURE_COLD static const char *verify_block(const PureModule *m, PureBlock block, int view, int row, uint32_t event, + uint32_t *at) { + if (block.start > m->code_count || block.length > m->code_count - block.start) return "code range outside module"; + unsigned char *target = calloc((size_t)block.length + 1, 1); + if (!target) return "out of memory"; + const char *why = verify_code(m, block, view, row, event, at, target); + free(target); + return why; +} + +PURE_COLD PureResult pure_module_read(const char *path, PureModule *out, char *error, size_t error_size) { + FILE *file = fopen(path, "rb"); + unsigned char *bytes = NULL; + size_t size = 0, capacity = 0; + bool ok = file != NULL; + /* The largest module is some 2 MiB: code, strings and constants at their limits. */ + while (ok && !feof(file) && capacity < (8u << 20)) { + capacity = capacity ? capacity * 2 : 1 << 16; + unsigned char *grown = realloc(bytes, capacity); + if (!grown) { ok = false; break; } + bytes = grown; + size += fread(bytes + size, 1, capacity - size, file); + ok = !ferror(file); + } + ok = ok && feof(file); + if (file) fclose(file); + PureResult result = PURE_NOT_FOUND; + if (!ok) { + if (error_size) snprintf(error, error_size, "cannot read %s", path); + pure_module_release(out); + } else result = pure_module_load(bytes, size, out, error, error_size); + free(bytes); + return result; +} + +void pure_module_release(PureModule *m) { + free(m->storage); + m->storage = NULL; + m->code = NULL; + m->constant_offset = m->constant_length = NULL; + m->constant_data = NULL; +} + +PURE_COLD PureResult pure_module_load(const void *bytes, size_t size, PureModule *out, + char *error, size_t error_size) { + const unsigned char *p = bytes; + const char *why; + uint32_t bad = 0; + PureResult result = PURE_INVALID; +#define REFUSE(message, index) do { why = message; bad = (uint32_t)(index); goto refused; } while (0) + if (error_size) error[0] = 0; + pure_module_release(out); + memset(out, 0, sizeof(*out)); + if (!p || size < PURE_MODULE_HEADER || memcmp(p, magic, sizeof(magic))) REFUSE("not a Pure module v5", 0); + out->states = (uint16_t)read16(p + 8); + out->inputs = (uint16_t)read16(p + 10); + out->views = (uint16_t)read16(p + 12); + out->handlers = (uint16_t)read16(p + 14); + out->code_count = read32(p + 16); + uint32_t strings = read32(p + 20); + out->fields = (uint16_t)read16(p + 24); + out->collections = (uint16_t)read16(p + 26); + out->constants = (uint16_t)read16(p + 28); + out->records = (uint16_t)read16(p + 30); + uint32_t constant_bytes = read32(p + 32); + out->record_fields = (uint16_t)read16(p + 36); + if (read16(p + 38)) REFUSE("reserved header bytes", 38); + if (out->states > PURE_MODULE_STATES || out->inputs > PURE_MODULE_INPUTS || + out->views > PURE_MODULE_VIEWS || out->handlers > PURE_MODULE_HANDLERS || + out->code_count > PURE_MODULE_CODE || strings > PURE_MODULE_STRINGS || + out->fields > PURE_MODULE_FIELDS || out->collections > PURE_MODULE_COLLECTIONS || + out->constants > PURE_MODULE_CONSTANTS || constant_bytes > PURE_MODULE_CONSTANT_BYTES || + out->records > PURE_MODULE_RECORDS || out->record_fields > PURE_MODULE_RECORD_FIELDS) { + result = PURE_LIMIT; + REFUSE("module exceeds a limit", 8); + } + size_t expected = PURE_MODULE_HEADER + (size_t)out->states * STATE_BYTES + + (size_t)out->collections * COLLECTION_BYTES + (size_t)out->inputs * INPUT_BYTES + + (size_t)out->fields * FIELD_BYTES + (size_t)out->constants * CONSTANT_BYTES + + (size_t)out->records * RECORD_BYTES + (size_t)out->record_fields * RECORD_FIELD_BYTES + + (size_t)out->views * VIEW_BYTES + (size_t)out->handlers * HANDLER_BYTES + + (size_t)out->code_count * OP_BYTES + strings + constant_bytes; + if (size != expected) REFUSE("module size", expected); + /* The code, the constants' offsets and lengths, then their bytes, in one block. */ + size_t storage = (size_t)out->code_count * sizeof(PureOp) + (size_t)out->constants * 2 * sizeof(uint32_t) + + constant_bytes; + if (!(out->storage = malloc(storage ? storage : 1))) { + result = PURE_ALLOCATION; + REFUSE("out of memory", 0); + } + out->code = out->storage; + out->constant_offset = (uint32_t *)(out->code + out->code_count); + out->constant_length = out->constant_offset + out->constants; + out->constant_data = (unsigned char *)(out->constant_length + out->constants); + const unsigned char *at = p + PURE_MODULE_HEADER; + const unsigned char *text = p + size - constant_bytes - strings; + if (constant_bytes) memcpy(out->constant_data, p + size - constant_bytes, constant_bytes); + for (uint32_t i = 0; i < out->states; ++i, at += STATE_BYTES) { + out->state_type[i] = (uint8_t)read32(at + 4); + if (!name_at(text, strings, read32(at), NAME_IDENTIFIER, out->state_names[i])) REFUSE("state name", i); + if (read32(at + 4) > PURE_STATE_INDEX) REFUSE("state type", i); + if (out->state_type[i] == PURE_STATE_NUM) { + out->initial[i] = read_double(at + 8); + if (!isfinite(out->initial[i])) REFUSE("non-finite initial value", i); + } else { + /* Flags: a mark (cursor), or a keyed list's key field + 1. */ + uint32_t flags = read32(at + 12); + bool cursor = out->state_type[i] == PURE_STATE_CURSOR, list = out->state_type[i] == PURE_STATE_LIST; + if ((flags && !(cursor && flags == PURE_CURSOR_STAYS) && !(list && flags <= PURE_RECORD_FIELDS)) || + read32(at + 8) > UINT16_MAX) REFUSE("state reference", i); + out->state_ref[i] = (uint16_t)read32(at + 8); + out->state_flags[i] = cursor ? (uint8_t)flags : 0; + out->state_key[i] = list ? (uint8_t)flags : 0; + } + } + for (uint32_t i = 0; i < out->collections; ++i, at += COLLECTION_BYTES) { + if (!name_at(text, strings, read32(at), NAME_IDENTIFIER, out->collection_names[i])) REFUSE("collection name", i); + if (read32(at + 4) != 1 || read32(at + 8) != 1) REFUSE("collection must hold bytes by key", i); + } + uint32_t next_field = 0; + const unsigned char *fields = at + (size_t)out->inputs * INPUT_BYTES; + for (uint32_t i = 0; i < out->inputs; ++i, at += INPUT_BYTES) { + PureInputShape *shape = &out->input[i]; + shape->kind = at[4]; + shape->keyed = at[5]; + shape->field_start = (uint16_t)read16(at + 12); + shape->field_count = (uint16_t)read16(at + 14); + if (!name_at(text, strings, read32(at), NAME_IDENTIFIER, out->input_names[i])) REFUSE("input name", i); + if (read16(at + 6) || at[5] > 1) REFUSE("input flags", i); + if (shape->kind == PURE_KIND_KEY) { + if (shape->keyed || shape->field_start || shape->field_count || + !name_at(text, strings, read32(at + 8), NAME_PRINTABLE, out->input_keys[i]) || + !key_name(out->input_keys[i])) REFUSE("input key", i); + for (uint32_t k = 0; k < i; ++k) + if (out->input[k].kind == PURE_KIND_KEY && !strcmp(out->input_keys[k], out->input_keys[i])) + REFUSE("duplicate key", i); + continue; + } + if (shape->kind == PURE_KIND_TEXT) { + if (shape->keyed || shape->field_start || shape->field_count || read32(at + 8)) + REFUSE("text input shape", i); + continue; + } + if (shape->kind == PURE_KIND_TIMER) { + shape->period = read32(at + 8); + if (shape->keyed || shape->field_start || shape->field_count || !shape->period || + shape->period > PURE_TIMER_LONGEST) REFUSE("timer input", i); + continue; + } + if ((shape->kind != PURE_KIND_MESSAGE && shape->kind != PURE_KIND_OUTPUT) || read32(at + 8) || + (shape->kind == PURE_KIND_OUTPUT && shape->keyed) || shape->field_start != next_field || + shape->field_count > out->fields - next_field) REFUSE("message shape", i); + /* The prefix holds the fixed fields and the variable fields' lengths + * in order, but the last variable field's: it takes the rest. */ + uint32_t last = UINT32_MAX; + for (uint32_t f = 0; f < shape->field_count; ++f) { + uint32_t type = read32(fields + (size_t)(next_field + f) * FIELD_BYTES + 4); + if (type == PURE_FIELD_BYTES || type == PURE_FIELD_TEXT) last = f; + } + for (uint32_t f = 0; f < shape->field_count; ++f) { + const unsigned char *entry = fields + (size_t)(next_field + f) * FIELD_BYTES; + PureField *field = &out->field[next_field + f]; + field->type = (uint8_t)read32(entry + 4); + if (!name_at(text, strings, read32(entry), NAME_PATH, field->name) || field->type < PURE_FIELD_U32 || + read32(entry + 4) > PURE_FIELD_TEXT) + REFUSE("message field", next_field + f); + /* A name is a field or a group, never both (user and user.name). */ + for (uint32_t k = 0; k < f; ++k) { + const char *a = out->field[next_field + k].name, *b = field->name; + size_t la = strlen(a), lb = strlen(b); + if (!strcmp(a, b)) REFUSE("duplicate field", next_field + f); + if ((la < lb && !memcmp(a, b, la) && b[la] == '.') || (lb < la && !memcmp(a, b, lb) && a[lb] == '.')) + REFUSE("field and group", next_field + f); + } + field->offset = f == last ? PURE_FIELD_REST : shape->prefix; + if (f != last) shape->prefix += field->type == PURE_FIELD_NUMBER ? 8 : 4; + } + next_field += shape->field_count; + } + if (next_field != out->fields) REFUSE("unused message fields", next_field); + at = fields + (size_t)out->fields * FIELD_BYTES; + for (uint32_t i = 0; i < out->constants; ++i, at += CONSTANT_BYTES) { + out->constant_offset[i] = read32(at); + out->constant_length[i] = read32(at + 4); + if (out->constant_offset[i] > constant_bytes || out->constant_length[i] > constant_bytes - out->constant_offset[i] || + !pure_utf8_valid((PureSpan){out->constant_data + out->constant_offset[i], out->constant_length[i]})) + REFUSE("text constant", i); + } + /* Records: fields in order, numbered from first; a text default is a constant. */ + const unsigned char *fields_at = at + (size_t)out->records * RECORD_BYTES; + uint32_t next_record_field = 0; + for (uint32_t i = 0; i < out->records; ++i, at += RECORD_BYTES) { + PureRecord *record = &out->record[i]; + record->first = (uint16_t)read16(at + 4); + record->count = (uint16_t)read16(at + 6); + if (!name_at(text, strings, read32(at), NAME_IDENTIFIER, out->record_names[i]) || record->first != next_record_field || + !record->count || record->count > PURE_RECORD_FIELDS || record->count > out->record_fields - next_record_field) + REFUSE("record", i); + for (uint32_t f = record->first; f < record->first + record->count; ++f) { + const unsigned char *entry = fields_at + (size_t)f * RECORD_FIELD_BYTES; + uint32_t type = read32(entry + 4); + out->record_field_text[f] = type == 1; + if (!name_at(text, strings, read32(entry), NAME_IDENTIFIER, out->record_field_names[f]) || type > 1) + REFUSE("record field", f); + for (uint32_t k = record->first; k < f; ++k) + if (!strcmp(out->record_field_names[k], out->record_field_names[f])) REFUSE("duplicate record field", f); + out->record_field_default[f] = type ? read32(entry + 8) : read_double(entry + 8); + if (type ? read32(entry + 12) || read32(entry + 8) >= out->constants : !isfinite(out->record_field_default[f])) + REFUSE("record field default", f); + } + next_record_field += record->count; + } + if (next_record_field != out->record_fields) REFUSE("unused record fields", next_record_field); + at = fields_at + (size_t)out->record_fields * RECORD_FIELD_BYTES; + for (uint32_t i = 0; i < out->states; ++i) + if ((out->state_type[i] == PURE_STATE_TEXT && out->state_ref[i] >= out->constants) || + (out->state_type[i] == PURE_STATE_CURSOR && !state_of(out, out->state_ref[i], PURE_STATE_TEXT)) || + (out->state_type[i] == PURE_STATE_LIST && + (out->state_ref[i] >= out->records || out->state_key[i] > out->record[out->state_ref[i]].count)) || + (out->state_type[i] == PURE_STATE_INDEX && !state_of(out, out->state_ref[i], PURE_STATE_LIST))) + REFUSE("state reference", i); + /* A table names its list in place of code; its columns follow it. */ + for (uint32_t i = 0; i < out->views; ++i, at += VIEW_BYTES) { + if (!name_at(text, strings, read32(at), NAME_IDENTIFIER, out->view_names[i])) REFUSE("view name", i); + out->view_type[i] = at[4]; + out->view_table[i] = (uint16_t)read16(at + 6); + out->view_code[i] = (PureBlock){read32(at + 8), read32(at + 12)}; + uint32_t table = out->view_table[i]; + if (at[4] > PURE_VIEW_TABLE || (at[5] && at[4] != PURE_VIEW_TABLE) || + (table && (table > i || out->view_type[table - 1] != PURE_VIEW_TABLE || at[4] == PURE_VIEW_TABLE))) + REFUSE("view type", i); + /* A table names its list in start, or, filtered, in the byte after its + * type (list + 1) with its filter's block in start and length. */ + if (at[4] == PURE_VIEW_TABLE) { + uint32_t list = at[5] ? at[5] - 1u : out->view_code[i].start; + if (!state_of(out, list, PURE_STATE_LIST) || !at[5] != !out->view_code[i].length) REFUSE("table list", i); + out->view_list[i] = (uint16_t)list; + } else if (table) out->view_list[i] = out->view_list[table - 1]; + } + for (uint32_t i = 0; i < out->handlers; ++i, at += HANDLER_BYTES) { + uint32_t event = read32(at); + out->handler[i] = (PureHandler){event, {read32(at + 4), read32(at + 8)}}; + int input = event_input(event); + if (event > 2u * out->inputs || (input >= 0 && out->input[input].kind != PURE_KIND_KEY && !(event & 1)) || + (input >= 0 && out->input[input].kind == PURE_KIND_OUTPUT)) + REFUSE("handler event", i); + } + for (uint32_t i = 0; i < out->code_count; ++i, at += OP_BYTES) { + if (at[1] || at[2] || at[3]) REFUSE("instruction padding", i); + out->code[i] = (PureOp){.op = at[0], .arg = read32(at + 4), .value = read_double(at + 8)}; + } + /* States, records, collections, inputs and views share one namespace. */ + const char *names[PURE_MODULE_STATES + PURE_MODULE_RECORDS + PURE_MODULE_COLLECTIONS + + PURE_MODULE_INPUTS + PURE_MODULE_VIEWS]; + size_t count = 0; + for (uint32_t i = 0; i < out->states; ++i) names[count++] = out->state_names[i]; + for (uint32_t i = 0; i < out->records; ++i) names[count++] = out->record_names[i]; + for (uint32_t i = 0; i < out->collections; ++i) names[count++] = out->collection_names[i]; + for (uint32_t i = 0; i < out->inputs; ++i) names[count++] = out->input_names[i]; + for (uint32_t i = 0; i < out->views; ++i) if (!out->view_table[i]) names[count++] = out->view_names[i]; + for (size_t i = 0; i < count; ++i) + for (size_t k = 0; k < i; ++k) + if (!strcmp(names[i], names[k])) REFUSE("duplicate name", i); + /* Column names are unique within their table. */ + for (uint32_t i = 0; i < out->views; ++i) + for (uint32_t k = 0; k < i; ++k) + if (out->view_table[i] && out->view_table[k] == out->view_table[i] && + !strcmp(out->view_names[i], out->view_names[k])) REFUSE("duplicate column", i); + for (uint32_t i = 0; i < out->views; ++i) { + bad = i; + bool table = out->view_type[i] == PURE_VIEW_TABLE; + if ((!table || out->view_code[i].length) && + (why = verify_block(out, out->view_code[i], table ? FILTER : out->view_type[i], + table || out->view_table[i] ? out->view_list[i] : -1, 0, &bad))) goto refused; + } + for (uint32_t i = 0; i < out->handlers; ++i) { + bad = i; + if ((why = verify_block(out, out->handler[i].code, -1, -1, out->handler[i].event, &bad))) goto refused; + } + return PURE_OK; +refused: + if (error_size) snprintf(error, error_size, "%s (%u)", why, bad); + pure_module_release(out); + return result; +#undef REFUSE +} + +static int find(const char (*names)[PURE_MODULE_NAME], unsigned count, const char *name) { + for (unsigned i = 0; i < count; ++i) + if (!strcmp(names[i], name)) return (int)i; + return -1; +} + +int pure_module_state(const PureModule *m, const char *name) { return find(m->state_names, m->states, name); } +int pure_module_input(const PureModule *m, const char *name) { return find(m->input_names, m->inputs, name); } +int pure_module_view(const PureModule *m, const char *name) { + for (uint32_t i = 0; i < m->views; ++i) + if (!m->view_table[i] && !strcmp(m->view_names[i], name)) return (int)i; + return -1; +} + +int pure_module_position(const PureModule *m, uint32_t view) { + if (view >= m->views || m->view_type[view] != PURE_VIEW_NUM || m->view_table[view]) return -1; + const PureBlock *block = &m->view_code[view]; + const PureOp *code = &m->code[block->start]; + return block->length == 2 && code[0].op == PURE_OP_INDEX_LOAD && code[1].op == PURE_OP_INDEX_NUM ? (int)code[0].arg : -1; +} + +int pure_module_text_state(const PureModule *m, uint32_t view) { + if (view >= m->views || m->view_type[view] != PURE_VIEW_TEXT || m->view_table[view]) return -1; + const PureBlock *block = &m->view_code[view]; + return block->length == 1 && m->code[block->start].op == PURE_OP_TEXT_LOAD ? (int)m->code[block->start].arg : -1; +} + +int pure_module_column(const PureModule *m, uint32_t table, const char *name) { + for (uint32_t i = 0; i < m->views; ++i) + if (m->view_table[i] == table + 1 && !strcmp(m->view_names[i], name)) return (int)i; + return -1; +} + +/* ---- Execution ------------------------------------------------------ */ + +/* IEEE 754-2019 minimum/maximum on finite values: -0 orders below +0. */ +static double minimum(double a, double b) { return a < b || (a == b && signbit(a)) ? a : b; } +static double maximum(double a, double b) { return a > b || (a == b && !signbit(a)) ? a : b; } + +typedef struct { double num; PureBytes bytes; } Slot; +typedef struct { + PureApp *app; + const PureInputShape *shape; /* message, or NULL */ + const char *key; /* a keyed message's key */ + int64_t base; /* the revision a message's edit was made against, or -1 */ + PureArena *arena; + double dt; + size_t row; /* the row a column is evaluated for */ + bool modified, exists; + uint32_t (*spans)[2]; /* a message's variable fields: start and size in the payload */ +} Event; + +static PureResult fault(PureApp *app, PureFault kind, uint32_t pc) { + app->fault = kind; + app->fault_pc = pc; + return kind == PURE_FAULT_LIMIT ? PURE_LIMIT : kind == PURE_FAULT_NOT_FOUND ? PURE_NOT_FOUND : + kind == PURE_FAULT_EXISTS ? PURE_CONFLICT : PURE_INVALID; +} + +static bool reserve(PureArena *arena, size_t more) { + if (more <= arena->capacity - arena->used) return true; + size_t capacity = arena->capacity ? arena->capacity : 256; + while (capacity - arena->used < more) { + if (capacity > SIZE_MAX / 2) return false; + capacity *= 2; + } + unsigned char *bytes = realloc(arena->bytes, capacity); + if (!bytes) return false; + arena->bytes = bytes; + arena->capacity = capacity; + return true; +} + +/* Visit a value's bytes in order, from wherever they live. */ +static PureResult visit_value(const PureApp *app, const PureArena *arena, PureBytes v, + bool (*visit)(void *, PureSpan), void *context) { + if (!v.length) return PURE_OK; + const unsigned char *direct = NULL; + switch (v.source) { + case FROM_PAYLOAD: direct = app->payload.data + v.offset; break; + case FROM_COPY: direct = app->copied + v.offset; break; + case FROM_CONSTANT: direct = app->module->constant_data + v.offset; break; + case FROM_ARENA: direct = arena->bytes + v.offset; break; + case FROM_TEXT: + return pure_draft_read_version(app->texts[v.owner], v.version, (size_t)v.offset, (size_t)v.length, + visit, context); + default: + return app->data.read(app->data.context, app->document, v.version, (size_t)v.offset, + (size_t)v.length, visit, context); + } + visit(context, (PureSpan){direct, (size_t)v.length}); + return PURE_OK; +} + +static bool append_span(void *context, PureSpan span) { + PureArena *arena = context; + memmove(arena->bytes + arena->used, span.data, span.size); + arena->used += span.size; + return true; +} + +/* Copy a value to the end of the arena. Room is reserved first, so reading + * an arena value while appending never follows a moved buffer. */ +static PureResult append_value(const PureApp *app, PureArena *arena, PureBytes v) { + if (!reserve(arena, (size_t)v.length)) return PURE_ALLOCATION; + return visit_value(app, arena, v, append_span, arena); +} + +/* A contiguous span of a value, copying into the arena when it is spread out. */ +static PureResult contiguous(const PureApp *app, PureArena *arena, PureBytes v, PureSpan *out) { + if (v.source == FROM_PAYLOAD || v.source == FROM_COPY || v.source == FROM_CONSTANT) { + const unsigned char *base = v.source == FROM_PAYLOAD ? app->payload.data : + v.source == FROM_COPY ? app->copied : app->module->constant_data; + *out = (PureSpan){v.length ? base + v.offset : NULL, (size_t)v.length}; + return PURE_OK; + } + if (v.source == FROM_ARENA) { + *out = (PureSpan){arena->bytes + v.offset, (size_t)v.length}; + return PURE_OK; + } + size_t start = arena->used; + PureResult result = append_value(app, arena, v); + *out = (PureSpan){arena->bytes + start, (size_t)v.length}; + return result; +} + +typedef struct { size_t count; unsigned unit; unsigned utf8; bool valid; } Measure; + +static bool measure(void *context, PureSpan span) { + Measure *m = context; + if (m->unit == 2) m->valid = m->valid && pure_utf8_step(&m->utf8, span); + else m->count += m->unit ? pure_utf8_newlines(span) : pure_utf8_scalars(span); + return true; +} + +static PureBytes text_of(const PureApp *app, uint32_t state) { + PureVersion version = pure_draft_version(app->texts[state]); + return (PureBytes){FROM_TEXT, (uint16_t)state, version, 0, version.bytes}; +} + +static void move_cursors(const PureModule *m, double *values, uint32_t text, size_t at, + size_t removed, size_t inserted) { + for (uint32_t c = 0; c < m->states; ++c) { + if (m->state_type[c] != PURE_STATE_CURSOR || m->state_ref[c] != text) continue; + double position = values[c]; + if (removed) { + if (position >= at + removed) position -= (double)removed; + else if (position > at) position = (double)at; + } else if (position > at || (position == at && !(m->state_flags[c] & PURE_CURSOR_STAYS))) + position += (double)inserted; + values[c] = position; + } +} + +/* Indices follow their item across an insert or remove; an index whose item + * was removed names the next item (or the last, or 0 in an empty list). */ +static void move_indices(const PureModule *m, double *values, uint32_t list, size_t count, + size_t at, bool inserted) { + double last = count ? (double)(count - 1) : 0; + for (uint32_t i = 0; i < m->states; ++i) { + if (m->state_type[i] != PURE_STATE_INDEX || m->state_ref[i] != list) continue; + if (inserted) { + if (count > 1 && values[i] >= (double)at) ++values[i]; + } else { + if (values[i] > (double)at) --values[i]; + values[i] = minimum(values[i], last); + } + } +} + +static bool text_field(const PureModule *m, uint32_t list, uint32_t field) { + return m->record_field_text[m->record[m->state_ref[list]].first + field]; +} + +/* Append bytes to the arena as a value of it. */ +static PureResult keep_bytes(PureArena *arena, const void *bytes, size_t length, PureBytes *out) { + if (!reserve(arena, length)) return PURE_ALLOCATION; + if (length) memcpy(arena->bytes + arena->used, bytes, length); + *out = (PureBytes){FROM_ARENA, 0, {0, 0}, arena->used, length}; + arena->used += length; + return PURE_OK; +} + +/* Run a verified block. Types and stack bounds were proven at load. A change + * the data refuses (a size limit, a missing item) fails the event with its + * fault; other failures pass through. */ +typedef struct { unsigned char *at; } Copy; + +static bool copy_out(void *context, PureSpan span) { + Copy *copy = context; + if (span.size) memcpy(copy->at, span.data, span.size); + copy->at += span.size; + return true; +} + +/* An output's message from its field values, laid out as a message's + * payload (size bytes), numbered and kept with the event's changes. */ +static PureResult send(PureApp *app, uint32_t output, const Slot *fields, const PureArena *arena, size_t size) { + const PureModule *m = app->module; + const PureInputShape *shape = &m->input[output]; + if (app->sent_count == app->sent_capacity) { + size_t capacity = app->sent_capacity ? 2 * app->sent_capacity : 16; + struct PureSent *grown = realloc(app->sent, capacity * sizeof(*grown)); + if (!grown) return PURE_ALLOCATION; + app->sent = grown; + app->sent_capacity = capacity; + } + unsigned char *payload = malloc(size ? size : 1); + if (!payload) return PURE_ALLOCATION; + Copy copy = {payload + shape->prefix}; + for (uint32_t f = 0; f < shape->field_count; ++f) { + const PureField *field = &m->field[shape->field_start + f]; + if (field->type == PURE_FIELD_U32) write32(payload + field->offset, (uint32_t)fields[f].num); + else if (field->type == PURE_FIELD_NUMBER) { + uint64_t bits; + memcpy(&bits, &fields[f].num, 8); + write32(payload + field->offset, (uint32_t)bits); + write32(payload + field->offset + 4, (uint32_t)(bits >> 32)); + } else { + if (field->offset != PURE_FIELD_REST) write32(payload + field->offset, (uint32_t)fields[f].bytes.length); + PureResult result = visit_value(app, arena, fields[f].bytes, copy_out, ©); + if (result != PURE_OK) { free(payload); return result; } + } + } + app->sent[app->sent_count++] = (struct PureSent){output, ++app->last_sent[output], payload, size, false}; + app->links_changed = true; + return PURE_OK; +} + +static PureResult run(const PureModule *m, double *values, PureBlock block, Event *ev, Slot *result) { + Slot stack[PURE_MODULE_STACK]; + size_t sp = 0; + PureApp *app = ev->app; + PureArena *arena = ev->arena; + PureResult status; + PureFault kind; + const PureOp *op = NULL; + for (uint32_t pc = block.start, end = block.start + block.length; pc < end;) { + op = &m->code[pc++]; + uint32_t arg = op->arg; + Slot *top = sp ? &stack[sp - 1] : stack; + switch (op->op) { + case PURE_OP_CONST: stack[sp++].num = op->value; continue; + case PURE_OP_LOAD: stack[sp++].num = values[arg]; continue; + case PURE_OP_DT: stack[sp++].num = ev->dt; continue; + case PURE_OP_NOW: stack[sp++].num = app->now; continue; + case PURE_OP_FLOOR: top->num = floor(top->num); continue; + case PURE_OP_STORE: case PURE_OP_CUR_STORE: values[arg] = stack[--sp].num; continue; + case PURE_OP_JZ: if (stack[--sp].num == 0) pc = arg; continue; + case PURE_OP_JMP: pc = arg; continue; + case PURE_OP_NEG: top->num = -top->num; continue; + case PURE_OP_NOT: top->num = top->num == 0; continue; + case PURE_OP_CLAMP: { + double high = stack[--sp].num, low = stack[--sp].num; + if (low > high) { kind = PURE_FAULT_CLAMP; goto failed; } + stack[sp - 1].num = maximum(low, minimum(stack[sp - 1].num, high)); + continue; + } + case PURE_OP_FIELD: { + const PureField *field = &m->field[ev->shape->field_start + arg]; + if (field->type == PURE_FIELD_U32) stack[sp++].num = read32(app->payload.data + field->offset); + else if (field->type == PURE_FIELD_NUMBER) stack[sp++].num = read_double(app->payload.data + field->offset); + else stack[sp++].bytes = (PureBytes){FROM_PAYLOAD, 0, {0, 0}, ev->spans[arg][0], ev->spans[arg][1]}; + continue; + } + case PURE_OP_DOC: case PURE_OP_DOC_SIZE: { + if (op->op == PURE_OP_DOC && !ev->exists) { kind = PURE_FAULT_NOT_FOUND; goto failed; } + PureVersion version = app->data.version(app->data.context, app->document); + if (op->op == PURE_OP_DOC) stack[sp++].bytes = (PureBytes){FROM_DOCUMENT, 0, version, 0, version.bytes}; + else stack[sp++].num = (double)version.bytes; + continue; + } + case PURE_OP_LEN: case PURE_OP_TEXT_BYTES: top->num = (double)top->bytes.length; continue; + case PURE_OP_REPLACE: { + PureBytes insert = stack[--sp].bytes; + double last = stack[--sp].num, first = stack[--sp].num; + double size = (double)app->data.version(app->data.context, app->document).bytes; + if (first != floor(first) || last != floor(last) || first < 0 || last < first || last > size) { + kind = PURE_FAULT_LIMIT; + goto failed; + } + PureSpan span; + size_t mark = arena->used; + if ((status = contiguous(app, arena, insert, &span)) == PURE_OK) + status = app->data.splice(app->data.context, app->document, (size_t)first, (size_t)(last - first), span); + arena->used = mark; + if (status != PURE_OK) goto refused; + ev->modified = ev->exists = true; + continue; + } + /* A reply outlives the arena mark of later statements: keep it by value. */ + case PURE_OP_REPLY: app->reply = stack[--sp].bytes; app->has_reply = true; continue; + case PURE_OP_REQUIRE: if (stack[--sp].num == 0) { kind = PURE_FAULT_LIMIT; goto failed; } continue; + case PURE_OP_TEXT_CONST: + stack[sp++].bytes = (PureBytes){FROM_CONSTANT, 0, {0, 0}, m->constant_offset[arg], m->constant_length[arg]}; + continue; + case PURE_OP_TEXT_LOAD: stack[sp++].bytes = text_of(app, arg); continue; + case PURE_OP_TEXT_INPUT: stack[sp++].bytes = (PureBytes){FROM_PAYLOAD, 0, {0, 0}, 0, app->payload.size}; continue; + case PURE_OP_NUM_TEXT: { + char digits[32]; + if ((status = keep_bytes(arena, digits, pure_format_number(top->num, digits), &top->bytes)) != PURE_OK) + return status; + continue; + } + case PURE_OP_CONCAT: { + PureBytes right = stack[--sp].bytes, left = stack[sp - 1].bytes; + size_t start = arena->used; + if ((status = append_value(app, arena, left)) != PURE_OK || + (status = append_value(app, arena, right)) != PURE_OK) return status; + stack[sp - 1].bytes = (PureBytes){FROM_ARENA, 0, {0, 0}, start, left.length + right.length}; + continue; + } + case PURE_OP_CHARS: case PURE_OP_LINES: case PURE_OP_TEXT_FROM: { + Measure count = {0, op->op == PURE_OP_LINES ? 1 : op->op == PURE_OP_TEXT_FROM ? 2 : 0, 0, true}; + if ((status = visit_value(app, arena, top->bytes, measure, &count)) != PURE_OK) return status; + if (op->op != PURE_OP_TEXT_FROM) top->num = (double)(count.count + (op->op == PURE_OP_LINES)); + else if (!count.valid || !pure_utf8_complete(count.utf8)) { kind = PURE_FAULT_ENCODING; goto failed; } + continue; + } + /* Positions: a cursor or an index, with the text or list it is in. */ + case PURE_OP_CUR_LOAD: case PURE_OP_INDEX_LOAD: + stack[sp].num = values[arg]; + stack[sp++].bytes.owner = m->state_ref[arg]; + continue; + case PURE_OP_CUR_START: case PURE_OP_CUR_END: case PURE_OP_INDEX_FIRST: case PURE_OP_INDEX_LAST: + case PURE_OP_ROW: { + size_t last = op->op == PURE_OP_CUR_END ? pure_draft_size(app->texts[arg]) : + op->op == PURE_OP_INDEX_LAST ? pure_list_count(app->lists[arg]) : 0; + stack[sp].num = op->op == PURE_OP_ROW ? (double)ev->row : + op->op == PURE_OP_INDEX_LAST && last ? (double)(last - 1) : (double)last; + stack[sp++].bytes.owner = (uint16_t)arg; + continue; + } + case PURE_OP_CUR_MOVE: case PURE_OP_INDEX_MOVE: { + double count = stack[--sp].num; + Slot *at = &stack[sp - 1]; + if (count != floor(count)) { kind = PURE_FAULT_LIMIT; goto failed; } + if (op->op == PURE_OP_INDEX_MOVE) { + size_t items = pure_list_count(app->lists[at->bytes.owner]); + at->num = maximum(0, minimum(at->num + count, items ? (double)(items - 1) : 0)); + continue; + } + PureDraft *text = app->texts[at->bytes.owner]; + PureVersion version = pure_draft_version(text); + at->num = (double)(arg == PURE_UNIT_CHAR ? pure_text_step(text, version, (size_t)at->num, count) + : pure_text_line_step(text, version, (size_t)at->num, count)); + continue; + } + case PURE_OP_CUR_COUNT: { + PureDraft *text = app->texts[top->bytes.owner]; + top->num = (double)pure_text_count(text, pure_draft_version(text), (size_t)top->num, arg); + continue; + } + case PURE_OP_TEXT_INSERT: case PURE_OP_TEXT_SET: { + PureBytes insert = stack[--sp].bytes; + size_t at = op->op == PURE_OP_TEXT_INSERT ? (size_t)stack[--sp].num : 0; + size_t removed = op->op == PURE_OP_TEXT_SET ? pure_draft_size(app->texts[arg]) : 0; + PureSpan span; + size_t mark = arena->used; + if ((status = contiguous(app, arena, insert, &span)) == PURE_OK) + status = pure_draft_splice(app->texts[arg], at, removed, span); + arena->used = mark; + if (status != PURE_OK) goto refused; + if (op->op == PURE_OP_TEXT_SET) { + for (uint32_t c = 0; c < m->states; ++c) + if (m->state_type[c] == PURE_STATE_CURSOR && m->state_ref[c] == arg) values[c] = 0; + } else move_cursors(m, values, arg, at, 0, span.size); + continue; + } + case PURE_OP_TEXT_REMOVE: { + double y = stack[--sp].num, x = stack[--sp].num; + size_t first = (size_t)minimum(x, y), last = (size_t)maximum(x, y); + if ((status = pure_draft_splice(app->texts[arg], first, last - first, (PureSpan){0})) != PURE_OK) goto refused; + if (last > first) move_cursors(m, values, arg, first, last - first, 0); + continue; + } + case PURE_OP_TEXT_LINE: { + PureDraft *text = app->texts[arg]; + PureVersion version = pure_draft_version(text); + size_t first = pure_text_line_start(text, version, (size_t)top->num); + size_t last = pure_text_line_end(text, version, (size_t)top->num); + top->bytes = (PureBytes){FROM_TEXT, (uint16_t)arg, version, first, last - first}; + continue; + } + case PURE_OP_BYTES_FROM: case PURE_OP_INDEX_NUM: continue; /* the same bytes or position, retyped */ + case PURE_OP_LIST_COUNT: stack[sp++].num = (double)pure_list_count(app->lists[arg]); continue; + case PURE_OP_SEND: { + const PureInputShape *output = &m->input[arg]; + size_t base = sp - output->field_count, size = output->prefix; + sp = base; + for (uint32_t f = 0; f < output->field_count; ++f) { + uint8_t type = m->field[output->field_start + f].type; + double number = stack[base + f].num; + if (type == PURE_FIELD_BYTES || type == PURE_FIELD_TEXT) size += (size_t)stack[base + f].bytes.length; + else if (type == PURE_FIELD_U32 && !(number >= 0 && number <= UINT32_MAX && number == floor(number))) { + kind = PURE_FAULT_LIMIT; + goto failed; + } + } + if (size > UINT32_MAX) { kind = PURE_FAULT_LIMIT; goto failed; } + if ((status = send(app, arg, stack + base, arena, size)) != PURE_OK) return status; + continue; + } + case PURE_OP_LIST_APPEND: case PURE_OP_LIST_INSERT: { + PureList *list = app->lists[arg]; + const PureRecord *record = &m->record[m->state_ref[arg]]; + size_t base = sp - record->count, count = pure_list_count(list), at = count; + sp = base; + if (op->op == PURE_OP_LIST_INSERT && (at = (size_t)stack[--sp].num) > count) { + kind = PURE_FAULT_NOT_FOUND; + goto failed; + } + /* Room for every text first, so no span moves while the next is copied. */ + size_t mark = arena->used, total = 0; + for (unsigned f = 0; f < record->count; ++f) + if (text_field(m, arg, f)) total += (size_t)stack[base + f].bytes.length; + if (!reserve(arena, total)) return PURE_ALLOCATION; + PureCell cells[PURE_RECORD_FIELDS]; + for (unsigned f = 0; f < record->count; ++f) { + PureSpan span = {0}; + if (text_field(m, arg, f) && (status = contiguous(app, arena, stack[base + f].bytes, &span)) != PURE_OK) + return status; + cells[f] = (PureCell){stack[base + f].num, (unsigned char *)span.data, span.size}; + } + if (m->state_key[arg]) { /* a keyed list places the item by its key */ + bool found; + unsigned key = m->state_key[arg] - 1u; + at = pure_list_seek(list, key, cells[key], &found); + if (found) { arena->used = mark; kind = PURE_FAULT_EXISTS; goto failed; } + } + status = pure_list_insert(list, at, cells, &app->undo); + arena->used = mark; + if (status != PURE_OK) goto refused; + move_indices(m, values, arg, pure_list_count(list), at, true); + continue; + } + case PURE_OP_LIST_REMOVE: { + size_t at = (size_t)stack[--sp].num; + if ((status = pure_list_remove(app->lists[arg], at, &app->undo)) != PURE_OK) goto refused; + move_indices(m, values, arg, pure_list_count(app->lists[arg]), at, false); + continue; + } + case PURE_OP_ITEM_GET: { + uint32_t list = list_of(arg), field = item_field(arg); + size_t at = (size_t)top->num; + if (at >= pure_list_count(app->lists[list])) { kind = PURE_FAULT_NOT_FOUND; goto failed; } + PureCell cell = pure_list_get(app->lists[list], at, field); + /* A text is copied: the item may change or go before the value is used. */ + if (!text_field(m, list, field)) top->num = cell.num; + else if ((status = keep_bytes(arena, cell.text, cell.size, &top->bytes)) != PURE_OK) return status; + continue; + } + case PURE_OP_ITEM_SET: { + uint32_t list = list_of(arg), field = item_field(arg); + Slot value = stack[--sp]; + size_t at = (size_t)stack[--sp].num, mark = arena->used; + PureSpan span = {0}; + status = text_field(m, list, field) ? contiguous(app, arena, value.bytes, &span) : PURE_OK; + if (status == PURE_OK) + status = pure_list_set(app->lists[list], at, field, + (PureCell){value.num, (unsigned char *)span.data, span.size}, &app->undo); + arena->used = mark; + if (status != PURE_OK) goto refused; + continue; + } + case PURE_OP_INDEX_STORE: { + /* An index from before a remove may be past the end. */ + double position = stack[--sp].num; + if (position && position >= (double)pure_list_count(app->lists[m->state_ref[arg]])) { + kind = PURE_FAULT_NOT_FOUND; + goto failed; + } + values[arg] = position; + continue; + } + case PURE_OP_FOLD: { + /* The block that follows runs once per item, as a column of the list. */ + unsigned how = arg & 0xFF; + PureBlock inner = {pc, arg >> 16}; + PureList *list = app->lists[arg >> 8 & 0xFF]; + pc += inner.length; + double total = 0; + bool any = false; + Event per = *ev; + for (size_t row = 0, items = pure_list_count(list); row < items; ++row) { + Slot out[2]; + size_t mark = arena->used; + per.row = row; + status = run(m, values, inner, &per, out); + arena->used = mark; + if (status != PURE_OK) return status; + double value = out[0].num; + if (how == PURE_FOLD_COUNT || how == PURE_FOLD_FIRST ? value == 0 : out[1].num == 0) continue; + if (how == PURE_FOLD_FIRST) { total = (double)row; any = true; break; } + total = how == PURE_FOLD_COUNT ? total + 1 : how == PURE_FOLD_SUM ? total + value : + !any ? value : how == PURE_FOLD_MAX ? maximum(total, value) : minimum(total, value); + any = true; + } + if (!any && how >= PURE_FOLD_MAX) { kind = PURE_FAULT_NOT_FOUND; goto failed; } + if (!isfinite(total)) { kind = PURE_FAULT_NON_FINITE; goto failed; } + stack[sp].num = total; + stack[sp++].bytes.owner = (uint16_t)(arg >> 8 & 0xFF); /* first: the list the index is in */ + continue; + } + case PURE_OP_TEXT_COMPARE: { + /* Texts order by their bytes: a shorter text before a longer one it begins. */ + PureBytes right = stack[--sp].bytes, left = stack[sp - 1].bytes; + size_t mark = arena->used; + PureSpan a, b; + if (!reserve(arena, (size_t)(left.length + right.length))) return PURE_ALLOCATION; + if ((status = contiguous(app, arena, left, &a)) != PURE_OK || + (status = contiguous(app, arena, right, &b)) != PURE_OK) return status; + size_t shorter = a.size < b.size ? a.size : b.size; + int order = shorter ? memcmp(a.data, b.data, shorter) : 0; + if (!order) order = (a.size > b.size) - (a.size < b.size); + arena->used = mark; + stack[sp - 1].num = arg == PURE_LESS ? order < 0 : arg == PURE_LESS_EQUAL ? order <= 0 : + arg == PURE_GREATER ? order > 0 : arg == PURE_GREATER_EQUAL ? order >= 0 : + arg == PURE_EQUAL ? order == 0 : order != 0; + continue; + } + case PURE_OP_LIST_FIND: case PURE_OP_LIST_HAS: { + /* A keyed list's item by key, found by halving: FIND gives its index, HAS whether it is there. */ + unsigned key = m->state_key[arg] - 1u; + size_t mark = arena->used; + PureCell cell = {top->num, NULL, 0}; + if (text_field(m, arg, key)) { + PureSpan span; + if ((status = contiguous(app, arena, top->bytes, &span)) != PURE_OK) return status; + cell = (PureCell){0, (unsigned char *)span.data, span.size}; + } + bool found; + size_t at = pure_list_seek(app->lists[arg], key, cell, &found); + arena->used = mark; + if (op->op == PURE_OP_LIST_HAS) { top->num = found; continue; } + if (!found) { kind = PURE_FAULT_NOT_FOUND; goto failed; } + top->num = (double)at; + top->bytes.owner = (uint16_t)arg; + continue; + } + case PURE_OP_PICK: stack[sp] = stack[sp - 1 - arg]; ++sp; continue; + case PURE_OP_SLIDE: stack[sp - 1 - arg] = stack[sp - 1]; sp -= arg; continue; + default: break; + } + double b = stack[--sp].num, a = stack[sp - 1].num, value; + switch (op->op) { + case PURE_OP_ADD: value = a + b; break; + case PURE_OP_SUB: value = a - b; break; + case PURE_OP_MUL: value = a * b; break; + case PURE_OP_DIV: + if (b == 0) { kind = PURE_FAULT_DIVIDE; goto failed; } + value = a / b; + break; + case PURE_OP_LT: value = a < b; break; + case PURE_OP_LE: value = a <= b; break; + case PURE_OP_GT: value = a > b; break; + case PURE_OP_GE: value = a >= b; break; + case PURE_OP_EQ: value = a == b; break; + case PURE_OP_NE: value = a != b; break; + case PURE_OP_AND: value = a != 0 && b != 0; break; + case PURE_OP_OR: value = a != 0 || b != 0; break; + case PURE_OP_MIN: value = minimum(a, b); break; + case PURE_OP_MOD: /* the divisor's sign, as floor division leaves it (a zero too) */ + if (b == 0) { kind = PURE_FAULT_DIVIDE; goto failed; } + value = fmod(a, b); + if (value != 0 && (value < 0) != (b < 0)) value += b; + else if (value == 0) value = copysign(0.0, b); + break; + default: value = maximum(a, b); break; + } + if (!isfinite(value)) { kind = PURE_FAULT_NON_FINITE; goto failed; } + stack[sp - 1].num = value; + } + if (result) memcpy(result, stack, sp * sizeof(*stack)); /* a view's value, or a fold block's numbers */ + return PURE_OK; +refused: + kind = status == PURE_LIMIT ? PURE_FAULT_LIMIT : status == PURE_NOT_FOUND ? PURE_FAULT_NOT_FOUND : PURE_FAULT_NONE; + if (kind == PURE_FAULT_NONE) return status; +failed: + return fault(app, kind, (uint32_t)(op - m->code)); +} + +PURE_COLD static PureResult new_text(PureDraft **out, const PureModule *m, uint32_t constant) { + *out = pure_draft_new(); + if (!*out) return PURE_ALLOCATION; + PureSpan initial = {m->constant_data + m->constant_offset[constant], m->constant_length[constant]}; + PureResult result = pure_draft_splice(*out, 0, 0, initial); + if (result != PURE_OK) { pure_draft_close(*out); *out = NULL; } + return result; +} + +PURE_COLD static PureList *new_list(const PureModule *m, uint32_t record) { + return pure_list_new(m->record[record].count, m->record_field_text + m->record[record].first); +} + +static bool pending(const PureApp *app, const void *document) { + for (unsigned i = 0; i < app->pending_count; ++i) if (app->pending[i].document == document) return true; + return false; +} + +void pure_app_finish(PureApp *app) { + /* A document in the unsaved burst stays open until the save. */ + if (app->document && !pending(app, app->document)) app->data.close(app->data.context, app->document); + free(app->copied); + app->document = NULL; + app->copied = NULL; + app->has_reply = false; + app->payload = (PureSpan){0}; + app->arena.used = 0; +} + +/* The start of a burst: what a failed save returns to. Text and stored list + * drafts stay held until the save, so every version since stays readable. */ +static void open_burst(PureApp *app) { + if (app->open) return; + const PureModule *m = app->module; + memcpy(app->durable_values, app->values, sizeof(app->values)); + app->durable_ticks = app->ticks; + app->durable_events = app->events; + for (uint32_t i = 0; i < m->states; ++i) { + if (app->texts[i]) { + pure_draft_hold(app->texts[i], true); + app->durable_texts[i] = pure_draft_version(app->texts[i]); + } + if (app->list_drafts[i]) { + pure_draft_hold(app->list_drafts[i], true); + app->durable_lists[i] = pure_draft_version(app->list_drafts[i]); + } + } + app->open = true; +} + +/* End a burst, keeping it (saved) or undoing all of it. The documents it held + * close, except the current event's, which pure_app_finish closes. */ +static void close_burst(PureApp *app, bool keep) { + for (unsigned i = 0; i < app->pending_count; ++i) + if (app->pending[i].document != app->document) app->data.close(app->data.context, app->pending[i].document); + app->pending_count = 0; + if (!app->open) return; + const PureModule *m = app->module; + for (uint32_t i = 0; i < m->states; ++i) { + if (app->texts[i]) { + if (!keep) pure_draft_restore(app->texts[i], app->durable_texts[i]); + pure_draft_hold(app->texts[i], false); + } + if (app->list_drafts[i]) { + if (!keep) pure_draft_restore(app->list_drafts[i], app->durable_lists[i]); + pure_draft_hold(app->list_drafts[i], false); + } + } + if (keep) pure_undo_commit(&app->undo); + else { + pure_undo_rollback(&app->undo, 0); + memcpy(app->values, app->durable_values, sizeof(app->values)); + app->ticks = app->durable_ticks; + app->events = app->durable_events; + ++app->changes; + } + app->open = false; +} + +static void drop_sent(PureApp *app, size_t count) { + while (app->sent_count > count) free(app->sent[--app->sent_count].payload); +} + +/* After a save: what it stored is the links' saved state (trimmed sends go), + * or, when it failed, the links return to the last saved state. */ +static void settle_links(PureApp *app, bool saved) { + if (saved) { + size_t kept = 0; + for (size_t i = 0; i < app->sent_count; ++i) { + if (app->sent[i].trimmed) free(app->sent[i].payload); + else app->sent[kept++] = app->sent[i]; + } + app->sent_count = app->sent_durable = kept; + memcpy(app->saved_sent, app->last_sent, sizeof(app->saved_sent)); + for (unsigned i = 0; i < app->heard_count; ++i) app->heard[i].saved = app->heard[i].seq; + } else { + drop_sent(app, app->sent_durable); + for (size_t i = 0; i < app->sent_count; ++i) app->sent[i].trimmed = false; + memcpy(app->last_sent, app->saved_sent, sizeof(app->last_sent)); + unsigned kept = 0; + for (unsigned i = 0; i < app->heard_count; ++i) + if (app->heard[i].saved) { + app->heard[kept] = app->heard[i]; + app->heard[kept++].seq = app->heard[i].saved; + } + app->heard_count = kept; + } + app->links_changed = false; +} + +PureResult pure_app_save(PureApp *app) { + void *documents[PURE_APP_PENDING]; + int64_t revisions[PURE_APP_PENDING]; + size_t count = 0; + for (unsigned i = 0; i < app->pending_count; ++i) + if (app->pending[i].edited) documents[count++] = app->pending[i].document; + PureResult result = pure_save_commit(app, app->values, documents, count, revisions); + settle_links(app, result == PURE_OK); + close_burst(app, result == PURE_OK); + return result; +} + +bool pure_app_defer(PureApp *app, bool deferred) { + if (deferred && !pure_save_enabled(app)) return false; + app->deferred = deferred; + return true; +} + +/* ---- Snapshots. Snapshots of one app form a chain from oldest to newest, + * each holding the next, so they go oldest first. List items the app lets go + * while a snapshot is its newest may be read by that one and older ones, so + * they go with it. */ +struct PureSnapshot { + unsigned refs; + const PureModule *module; + uint64_t changes; + double values[PURE_MODULE_STATES]; + PureDraft *texts[PURE_MODULE_STATES]; + PureList *lists[PURE_MODULE_STATES]; + PureRetired retired; + struct PureSnapshot *newer; +}; + +void pure_snapshot_hold(PureSnapshot *snapshot) { __atomic_add_fetch(&snapshot->refs, 1, __ATOMIC_RELAXED); } + +void pure_snapshot_release(PureSnapshot *snapshot) { + while (snapshot && !__atomic_sub_fetch(&snapshot->refs, 1, __ATOMIC_ACQ_REL)) { + PureSnapshot *newer = snapshot->newer; + for (uint32_t i = 0; i < PURE_MODULE_STATES; ++i) { + pure_draft_close(snapshot->texts[i]); + pure_list_free(snapshot->lists[i]); + } + pure_retired_free(&snapshot->retired); + free(snapshot); + snapshot = newer; + } +} + +void pure_app_stop(PureApp *app) { + pure_app_finish(app); + close_burst(app, true); /* unsaved changes are dropped with the app */ + for (uint32_t i = 0; i < PURE_MODULE_STATES && !app->reading; ++i) { + pure_draft_close(app->texts[i]); + pure_list_free(app->lists[i]); + pure_draft_close(app->list_drafts[i]); + } + /* Items the newest snapshot may still read go when it goes. */ + if (app->snapshot) { + app->snapshot->retired = app->retired; + pure_snapshot_release(app->snapshot); + } else + pure_retired_free(&app->retired); + pure_draft_close(app->stored_values); + drop_sent(app, 0); + free(app->sent); + free(app->heard); + free(app->carried); + pure_draft_close(app->stored_links); + free(app->pending); + pure_undo_free(&app->undo); + for (unsigned i = 0; i < app->row_tables; ++i) free(app->rows[i].items); + free(app->rows); + free(app->arena.bytes); + free(app->view_arena.bytes); + memset(app, 0, sizeof(*app)); +} + +/* Where one event began inside the burst: a failed event returns there. */ +typedef struct { + PureVersion texts[PURE_MODULE_STATES], lists[PURE_MODULE_STATES]; + size_t undo, sent; + uint64_t last_sent[PURE_MODULE_INPUTS]; + bool opened; +} Mark; + +static void mark_event(PureApp *app, Mark *mark) { + mark->opened = !app->open; + open_burst(app); + for (uint32_t i = 0; i < app->module->states; ++i) { + if (app->texts[i]) mark->texts[i] = pure_draft_version(app->texts[i]); + if (app->list_drafts[i]) mark->lists[i] = pure_draft_version(app->list_drafts[i]); + } + mark->undo = app->undo.count; + mark->sent = app->sent_count; + memcpy(mark->last_sent, app->last_sent, sizeof(mark->last_sent)); +} + +static void undo_event(PureApp *app, const Mark *mark) { + for (uint32_t i = 0; i < app->module->states; ++i) { + if (app->texts[i]) pure_draft_restore(app->texts[i], mark->texts[i]); + if (app->list_drafts[i]) pure_draft_restore(app->list_drafts[i], mark->lists[i]); + } + pure_undo_rollback(&app->undo, mark->undo); + drop_sent(app, mark->sent); + memcpy(app->last_sent, mark->last_sent, sizeof(app->last_sent)); + if (mark->opened) close_burst(app, true); /* nothing happened: release the holds */ +} + +/* The last number heard from source, or NULL. */ +static struct PureHeard *heard_from(PureApp *app, const char *source) { + for (unsigned i = 0; i < app->heard_count; ++i) + if (!strcmp(app->heard[i].source, source)) return &app->heard[i]; + return NULL; +} + +/* Hear seq from source (room for a new source was made before). */ +static void hear(PureApp *app, const char *source, uint64_t seq) { + struct PureHeard *heard = heard_from(app, source); + if (!heard) { + heard = &app->heard[app->heard_count++]; + *heard = (struct PureHeard){.saved = 0}; + memcpy(heard->source, source, strlen(source) + 1); + } + heard->seq = seq; + app->links_changed = true; +} + +static PureResult keep_reply(PureApp *app); + +/* One event: every handler for it runs in module order against pending + * states, all or nothing. A key, text or message event saves before it + * returns unless saving is deferred; a frame leaves that to the next event + * (frames come 60 times a second). A message's document joins the burst. */ +static PureResult dispatch(PureApp *app, uint32_t event, Event *ev) { + const PureModule *m = app->module; + double pending[PURE_MODULE_STATES]; + Mark mark; + mark_event(app, &mark); + memcpy(pending, app->values, sizeof(app->values)); + app->fault = PURE_FAULT_NONE; + app->fault_pc = UINT32_MAX; + PureResult result = PURE_OK; + for (uint32_t i = 0; i < m->handlers && result == PURE_OK; ++i) + if (m->handler[i].event == event) result = run(m, pending, m->handler[i].code, ev, NULL); + /* An edit needs the revision it was made against. A save rebases an + * edited document and releasing texts may reclaim earlier text versions: + * keep such a reply by copying it first. */ + if (result == PURE_OK && ev->modified && ev->base < 0) result = PURE_INVALID; + if (result == PURE_OK && app->has_reply && + ((app->reply.source == FROM_DOCUMENT && ev->modified) || app->reply.source == FROM_TEXT)) + result = keep_reply(app); + if (result != PURE_OK) { + undo_event(app, &mark); + return result; + } + memcpy(app->values, pending, sizeof(pending)); + ++app->events; + ++app->changes; + if (!event) ++app->ticks; + if (app->document) { + app->pending[app->pending_count].document = app->document; + app->pending[app->pending_count].edited = ev->modified; + memcpy(app->pending[app->pending_count++].key, ev->key, strlen(ev->key) + 1); + app->revision += ev->modified; /* a save moves an edited document one revision */ + } + if (app->delivering.pending) { + hear(app, app->delivering.source, app->delivering.seq); + app->delivering.pending = false; + } + return event && !app->deferred ? pure_app_save(app) : PURE_OK; +} + +PureResult pure_app_frame(PureApp *app) { + pure_app_finish(app); + Event ev = {.app = app, .arena = &app->arena, .dt = 1.0 / 60.0}; + return dispatch(app, 0, &ev); +} + +PureResult pure_app_tick(PureApp *app, uint32_t input) { + if (input >= app->module->inputs || app->module->input[input].kind != PURE_KIND_TIMER) return PURE_INVALID; + pure_app_finish(app); + Event ev = {.app = app, .arena = &app->arena}; + return dispatch(app, 1 + 2 * input, &ev); +} + +PureResult pure_app_input(PureApp *app, uint32_t input, PureEdge edge) { + if (input >= app->module->inputs || app->module->input[input].kind != PURE_KIND_KEY || + (edge != PURE_EDGE_DOWN && edge != PURE_EDGE_UP)) return PURE_INVALID; + pure_app_finish(app); + Event ev = {.app = app, .arena = &app->arena}; + return dispatch(app, 1 + 2 * input + (edge == PURE_EDGE_UP), &ev); +} + +PureResult pure_app_point(PureApp *app, uint32_t state, size_t position) { + const PureModule *m = app->module; + pure_app_finish(app); + if (state >= m->states || m->state_type[state] != PURE_STATE_INDEX) return PURE_INVALID; + if (position >= pure_list_count(app->lists[m->state_ref[state]])) return PURE_NOT_FOUND; + open_burst(app); /* what a failed save returns to */ + app->fault = PURE_FAULT_NONE; + app->fault_pc = UINT32_MAX; + app->values[state] = (double)position; + ++app->events; + ++app->changes; + return app->deferred ? PURE_OK : pure_app_save(app); +} + +PureResult pure_app_text(PureApp *app, uint32_t input, PureSpan text) { + pure_app_finish(app); + if (input >= app->module->inputs || app->module->input[input].kind != PURE_KIND_TEXT || + (text.size && !text.data) || !pure_utf8_valid(text)) return PURE_INVALID; + app->payload = text; + Event ev = {.app = app, .arena = &app->arena}; + PureResult result = dispatch(app, 1 + 2 * input, &ev); + app->payload = (PureSpan){0}; + return result; +} + +static PureResult keep_reply(PureApp *app) { + size_t length = (size_t)app->reply.length, start = app->arena.used; + unsigned char *copy = malloc(length ? length : 1); + if (!copy) return PURE_ALLOCATION; + PureResult result = append_value(app, &app->arena, app->reply); + if (result != PURE_OK) { free(copy); return result; } + if (length) memcpy(copy, app->arena.bytes + start, length); + app->arena.used = start; + app->copied = copy; + app->reply = (PureBytes){FROM_COPY, 0, {0, 0}, 0, length}; + return PURE_OK; +} + +/* A message whose variable fields are where placed says (start and size in + * the payload), or, without it, one after another after the prefix. */ +static PureResult message(PureApp *app, uint32_t input, const char *key, int64_t base, PureSpan payload, + const uint32_t *placed) { + pure_app_finish(app); + const PureModule *m = app->module; + app->fault = PURE_FAULT_NONE; + app->fault_pc = UINT32_MAX; + app->revision = 0; + if (input >= m->inputs || m->input[input].kind != PURE_KIND_MESSAGE || base < -1 || + (payload.size && !payload.data) || (m->input[input].keyed ? !document_key(key) : key != NULL)) + return PURE_INVALID; + const PureInputShape *shape = &m->input[input]; + if (payload.size < shape->prefix) return fault(app, PURE_FAULT_LIMIT, UINT32_MAX); + /* Where each variable field is; a length past the payload, a text that + * is not UTF-8 or a number that is not finite fails the message. */ + uint32_t spans[PURE_MODULE_FIELDS][2]; + size_t at = shape->prefix; + for (uint32_t f = 0; f < shape->field_count; ++f) { + const PureField *field = &m->field[shape->field_start + f]; + if (field->type == PURE_FIELD_NUMBER && !isfinite(read_double(payload.data + field->offset))) + return fault(app, PURE_FAULT_NON_FINITE, UINT32_MAX); + if (field->type != PURE_FIELD_BYTES && field->type != PURE_FIELD_TEXT) continue; + size_t start = placed ? placed[2 * f] : at; + if (start > payload.size) return fault(app, PURE_FAULT_LIMIT, UINT32_MAX); + size_t size = placed ? placed[2 * f + 1] : field->offset == PURE_FIELD_REST ? payload.size - at : + read32(payload.data + field->offset); + if (size > payload.size - start) return fault(app, PURE_FAULT_LIMIT, UINT32_MAX); + if (field->type == PURE_FIELD_TEXT && !pure_utf8_valid((PureSpan){size ? payload.data + start : NULL, size})) + return fault(app, PURE_FAULT_ENCODING, UINT32_MAX); + spans[f][0] = (uint32_t)start; + spans[f][1] = (uint32_t)size; + at = start + size; + } + if (shape->keyed && m->collections) { + if (!app->data.open) return PURE_INVALID; + /* A key joins a burst once, so its revision moves once per save. */ + bool seen = app->pending_count == PURE_APP_PENDING; + for (unsigned i = 0; i < app->pending_count && !seen; ++i) seen = !strcmp(app->pending[i].key, key); + if (seen) { + PureResult saved = pure_app_save(app); + if (saved != PURE_OK) return saved; + } + if (app->pending_count == app->pending_capacity) { + unsigned capacity = app->pending_capacity ? 2 * app->pending_capacity : 16; + struct PurePending *grown = realloc(app->pending, capacity * sizeof(*grown)); + if (!grown) return PURE_ALLOCATION; + app->pending = grown; + app->pending_capacity = capacity; + } + PureResult opened = app->data.open(app->data.context, 0, key, &app->document, &app->revision); + if (opened != PURE_OK) { app->document = NULL; return opened; } + if (base >= 0 && base != app->revision) { pure_app_finish(app); return PURE_CONFLICT; } + } + app->payload = payload; + Event ev = {.app = app, .shape = shape, .key = key, .base = base, .arena = &app->arena, .exists = app->revision > 0, + .spans = spans}; + PureResult result = dispatch(app, 1 + 2 * input, &ev); + if (result != PURE_OK) pure_app_finish(app); + return result; +} + +PureResult pure_app_message(PureApp *app, uint32_t input, const char *key, int64_t base, PureSpan payload) { + return message(app, input, key, base, payload, NULL); +} + +PureResult pure_app_message_fields(PureApp *app, uint32_t input, const char *key, int64_t base, PureSpan payload, + const uint32_t *placed) { + return message(app, input, key, base, payload, placed); +} + +void pure_app_outbox(const PureApp *app, PureSentVisit visit, void *context) { + for (size_t i = 0; i < app->sent_durable; ++i) { + const struct PureSent *sent = &app->sent[i]; + if (!sent->trimmed && !visit(context, sent->output, sent->seq, (PureSpan){sent->payload, sent->size})) return; + } +} + +void pure_app_outbox_newest(const PureApp *app, PureSentVisit visit, void *context) { + for (size_t i = app->sent_durable; i-- > 0;) { + const struct PureSent *sent = &app->sent[i]; + if (!sent->trimmed && !visit(context, sent->output, sent->seq, (PureSpan){sent->payload, sent->size})) return; + } +} + +void pure_app_trim(PureApp *app, uint32_t output, uint64_t through) { + for (size_t i = 0; i < app->sent_durable; ++i) + if (app->sent[i].output == output && app->sent[i].seq <= through && !app->sent[i].trimmed) { + app->sent[i].trimmed = true; + app->links_changed = true; + } +} + +PureResult pure_app_deliver(PureApp *app, uint32_t input, const char *source, uint64_t seq, PureSpan payload, + const uint32_t *placed) { + const PureModule *m = app->module; + size_t length = source ? strlen(source) : 0; + app->duplicate = false; + if (input >= m->inputs || m->input[input].kind != PURE_KIND_MESSAGE || m->input[input].keyed || !length || + length > PURE_SOURCE || !seq) return PURE_INVALID; + for (size_t i = 0; i < length; ++i) + if (source[i] <= ' ' || source[i] > '~') return PURE_INVALID; + struct PureHeard *heard = heard_from(app, source); + if (heard && seq <= heard->seq) { + pure_app_finish(app); + app->duplicate = true; + return PURE_OK; + } + if (!heard && app->heard_count == app->heard_capacity) { + unsigned capacity = app->heard_capacity ? 2 * app->heard_capacity : 4; + struct PureHeard *grown = realloc(app->heard, capacity * sizeof(*grown)); + if (!grown) return PURE_ALLOCATION; + app->heard = grown; + app->heard_capacity = capacity; + } + app->delivering.source = source; + app->delivering.seq = seq; + app->delivering.pending = true; + PureResult result = message(app, input, NULL, -1, payload, placed); + if (!app->delivering.pending) return result; + /* Not applied. Refused by the app (a fault), the message was delivered + * all the same: its number is heard, saved like a key event's changes. */ + app->delivering.pending = false; + if (app->fault == PURE_FAULT_NONE) return result; + Mark mark; + mark_event(app, &mark); + hear(app, source, seq); + PureResult saved = app->deferred ? PURE_OK : pure_app_save(app); + return saved == PURE_OK ? result : saved; +} + +PureResult pure_app_reply(const PureApp *app, bool (*visit)(void *, PureSpan), void *context) { + if (!app->has_reply) return PURE_OK; + return visit_value(app, &app->arena, app->reply, visit, context); +} + +/* A view that fails reports it by its result; the fault stays the last event's. */ +static PureResult evaluate(PureApp *app, uint32_t view, size_t row, Slot *out) { + double values[PURE_MODULE_STATES]; + memcpy(values, app->values, sizeof(values)); + app->view_arena.used = 0; + Event ev = {.app = app, .arena = &app->view_arena, .row = row}; + PureFault fault = app->fault; + uint32_t fault_pc = app->fault_pc; + PureResult result = run(app->module, values, app->module->view_code[view], &ev, out); + app->fault = fault; + app->fault_pc = fault_pc; + return result; +} + +/* A filtered table's items, as fresh as the app's states: the filter runs + * once per item after each change (an item it fails on is left out), not + * once per cell. NULL for a table without a filter, or without room. */ +static struct PureRows *filtered(PureApp *app, uint32_t table) { + const PureModule *m = app->module; + if (!m->view_code[table].length) return NULL; + struct PureRows *rows = NULL; + for (unsigned i = 0; i < app->row_tables && !rows; ++i) if (app->rows[i].table == table) rows = &app->rows[i]; + if (!rows) { + struct PureRows *grown = realloc(app->rows, (app->row_tables + 1) * sizeof(*grown)); + if (!grown) return NULL; + app->rows = grown; + rows = &app->rows[app->row_tables++]; + *rows = (struct PureRows){.table = table, .changes = UINT64_MAX}; + } + if (rows->changes == app->changes) return rows; + rows->count = 0; + for (size_t item = 0, items = pure_list_count(app->lists[m->view_list[table]]); item < items; ++item) { + Slot keep; + if (evaluate(app, table, item, &keep) != PURE_OK || keep.num == 0) continue; + if (rows->count == rows->capacity) { + size_t capacity = rows->capacity ? 2 * rows->capacity : 16; + size_t *grown = realloc(rows->items, capacity * sizeof(*grown)); + if (!grown) return NULL; + rows->items = grown; + rows->capacity = capacity; + } + rows->items[rows->count++] = item; + } + rows->changes = app->changes; + return rows; +} + +bool pure_app_row_item(PureApp *app, uint32_t table, size_t row, size_t *item) { + const PureModule *m = app->module; + if (table >= m->views || m->view_type[table] != PURE_VIEW_TABLE) return false; + if (!m->view_code[table].length) { + *item = row; + return row < pure_list_count(app->lists[m->view_list[table]]); + } + struct PureRows *rows = filtered(app, table); + if (!rows || row >= rows->count) return false; + *item = rows->items[row]; + return true; +} + +bool pure_app_item_row(PureApp *app, uint32_t table, size_t item, size_t *row) { + const PureModule *m = app->module; + if (table >= m->views || m->view_type[table] != PURE_VIEW_TABLE) return false; + if (!m->view_code[table].length) { + *row = item; + return item < pure_list_count(app->lists[m->view_list[table]]); + } + struct PureRows *rows = filtered(app, table); + size_t low = 0, high = rows ? rows->count : 0; /* the items are in order */ + while (low < high) { + size_t middle = low + (high - low) / 2; + if (rows->items[middle] < item) low = middle + 1; + else high = middle; + } + if (low == (rows ? rows->count : 0) || rows->items[low] != item) return false; + *row = low; + return true; +} + +/* A view outside a table (column false), or a column and a row of its table. */ +static PureResult view_of(PureApp *app, uint32_t view, bool column, size_t row, uint8_t type, Slot *slot) { + const PureModule *m = app->module; + if (view >= m->views || m->view_type[view] != type || (m->view_table[view] != 0) != column) return PURE_INVALID; + if (column && !pure_app_row_item(app, m->view_table[view] - 1u, row, &row)) return PURE_NOT_FOUND; + return evaluate(app, view, row, slot); +} + +bool pure_app_view(PureApp *app, uint32_t view, double *out) { + Slot slot; + if (view_of(app, view, false, 0, PURE_VIEW_NUM, &slot) != PURE_OK) return false; + *out = slot.num; + return true; +} + +PureResult pure_app_view_text(PureApp *app, uint32_t view, bool (*visit)(void *, PureSpan), void *context) { + Slot slot; + PureResult result = view_of(app, view, false, 0, PURE_VIEW_TEXT, &slot); + return result == PURE_OK ? visit_value(app, &app->view_arena, slot.bytes, visit, context) : result; +} + +size_t pure_app_rows(PureApp *app, uint32_t table) { + const PureModule *m = app->module; + if (table >= m->views || m->view_type[table] != PURE_VIEW_TABLE) return 0; + struct PureRows *rows = filtered(app, table); + return rows ? rows->count : m->view_code[table].length ? 0 : pure_list_count(app->lists[m->view_list[table]]); +} + +bool pure_app_cell(PureApp *app, uint32_t column, size_t row, double *out) { + Slot slot; + if (view_of(app, column, true, row, PURE_VIEW_NUM, &slot) != PURE_OK) return false; + *out = slot.num; + return true; +} + +PureResult pure_app_cell_text(PureApp *app, uint32_t column, size_t row, bool (*visit)(void *, PureSpan), void *context) { + Slot slot; + PureResult result = view_of(app, column, true, row, PURE_VIEW_TEXT, &slot); + return result == PURE_OK ? visit_value(app, &app->view_arena, slot.bytes, visit, context) : result; +} + +PureSnapshot *pure_app_snapshot(PureApp *app) { + if (app->open || app->reading) return NULL; + const PureModule *m = app->module; + PureSnapshot *made = calloc(1, sizeof(*made)), *last = app->snapshot; + if (!made) return NULL; + made->refs = 1; + made->module = m; + made->changes = app->changes; + memcpy(made->values, app->values, sizeof(made->values)); + bool ok = true; + for (uint32_t i = 0; i < m->states && ok; ++i) { + if (app->texts[i]) ok = (made->texts[i] = pure_draft_freeze(app->texts[i])) != NULL; + if (!ok || !app->lists[i]) continue; + if (last && last->lists[i] && pure_list_current(last->lists[i], app->lists[i])) { + pure_list_hold(last->lists[i]); + made->lists[i] = last->lists[i]; + } else + ok = (made->lists[i] = pure_list_share(app->lists[i], &app->retired)) != NULL; + } + if (!ok) { + pure_snapshot_release(made); + return NULL; + } + made->refs = last ? 3 : 2; /* the app's, the caller's and the last one's */ + if (last) { + last->retired = app->retired; + last->newer = made; + pure_snapshot_release(last); + } else + pure_retired_free(&app->retired); /* shared only by a snapshot never made */ + app->retired = (PureRetired){0}; + app->snapshot = made; + return made; +} + +void pure_app_read(PureApp *reader, const PureSnapshot *snapshot) { + reader->module = snapshot->module; + reader->reading = true; + reader->changes = snapshot->changes; /* what the row cache is fresh for */ + memcpy(reader->values, snapshot->values, sizeof(reader->values)); + memcpy(reader->texts, snapshot->texts, sizeof(reader->texts)); + memcpy(reader->lists, snapshot->lists, sizeof(reader->lists)); +} + +/* A list with record's fields: each takes the field of `from` with the same + * name and kind, or its default. */ +PURE_COLD PureResult pure_list_migrate(PureList **out, const PureList *from, const char *const *names, + const uint8_t *text, unsigned count, const PureModule *m, uint32_t record) { + const PureRecord *r = &m->record[record]; + int source[PURE_RECORD_FIELDS]; + for (unsigned f = 0; f < r->count; ++f) { + source[f] = -1; + for (unsigned k = 0; k < count; ++k) + if (!strcmp(m->record_field_names[r->first + f], names[k]) && m->record_field_text[r->first + f] == text[k]) + source[f] = (int)k; + } + if (!(*out = new_list(m, record))) return PURE_ALLOCATION; + PureResult result = PURE_OK; + for (size_t at = 0; result == PURE_OK && at < pure_list_count(from); ++at) { + PureCell cells[PURE_RECORD_FIELDS]; + for (unsigned f = 0; f < r->count; ++f) { + uint32_t field = r->first + f, constant = (uint32_t)m->record_field_default[field]; + cells[f] = source[f] >= 0 ? pure_list_get(from, at, (unsigned)source[f]) : + m->record_field_text[field] ? + (PureCell){0, (unsigned char *)m->constant_data + m->constant_offset[constant], + m->constant_length[constant]} : + (PureCell){m->record_field_default[field], NULL, 0}; + } + result = pure_list_insert(*out, at, cells, NULL); + } + if (result != PURE_OK) { pure_list_free(*out); *out = NULL; } + return result; +} + +/* A kept list keeps its items; with the same record it is the same list. */ +PURE_COLD static PureResult keep_list(PureList **out, PureList *from, const PureModule *old, uint32_t old_record, + const PureModule *m, uint32_t record) { + const PureRecord *r = &m->record[record], *o = &old->record[old_record]; + const char *names[PURE_RECORD_FIELDS]; + bool same = r->count == o->count; + for (unsigned k = 0; k < o->count; ++k) { + names[k] = old->record_field_names[o->first + k]; + same = same && !strcmp(names[k], m->record_field_names[r->first + k]) && + old->record_field_text[o->first + k] == m->record_field_text[r->first + k]; + } + if (same) { *out = from; return PURE_OK; } + return pure_list_migrate(out, from, names, old->record_field_text + o->first, o->count, m, record); +} + +/* Open a module in an app. States keep their values by name and kind (texts + * their content, cursors their position in it, lists their items, moved by + * field name when the record changed); every other state starts from its + * stored value, or its initial one. A list whose record changed is stored + * again, and the next event or save publishes the module's states; a state + * the module drops stays stored as it was. Starting an app opens its module + * over none. */ +/* Outputs of old that module has by name and with the same fields keep their + * sends and numbers; one it lacks or changed refuses the module while sends + * are left on it (CONFLICT), and otherwise keeps its number for later. */ +PURE_COLD static PureResult remap_outputs(PureApp *app, const PureModule *old, const PureModule *module, bool apply) { + int map[PURE_MODULE_INPUTS]; + for (uint32_t i = 0; i < old->inputs; ++i) { + map[i] = -1; + if (old->input[i].kind != PURE_KIND_OUTPUT) continue; + int to = pure_module_input(module, old->input_names[i]); + bool same = to >= 0 && module->input[to].kind == PURE_KIND_OUTPUT && + module->input[to].field_count == old->input[i].field_count; + for (uint32_t f = 0; same && f < old->input[i].field_count; ++f) + same = module->field[module->input[to].field_start + f].type == old->field[old->input[i].field_start + f].type; + map[i] = same ? to : -1; + for (size_t s = 0; !same && s < app->sent_count; ++s) + if (app->sent[s].output == i) return PURE_CONFLICT; + } + if (!apply) return PURE_OK; + uint64_t last[PURE_MODULE_INPUTS] = {0}, saved[PURE_MODULE_INPUTS] = {0}; + for (uint32_t i = 0; i < old->inputs; ++i) { + if (old->input[i].kind != PURE_KIND_OUTPUT || !app->last_sent[i]) continue; + if (map[i] >= 0) { + last[map[i]] = app->last_sent[i]; + saved[map[i]] = app->saved_sent[i]; + continue; + } + struct PureCarried *grown = realloc(app->carried, (app->carried_count + 1) * sizeof(*grown)); + if (!grown) continue; /* its numbers would start again: kept only while memory allows */ + app->carried = grown; + memcpy(grown[app->carried_count].name, old->input_names[i], PURE_MODULE_NAME); + grown[app->carried_count++].last = app->last_sent[i]; + app->links_changed = true; + } + for (unsigned c = 0; c < app->carried_count;) { + int to = pure_module_input(module, app->carried[c].name); + if (to < 0 || module->input[to].kind != PURE_KIND_OUTPUT || last[to]) { ++c; continue; } + last[to] = saved[to] = app->carried[c].last; + app->carried[c] = app->carried[--app->carried_count]; + app->links_changed = true; + } + for (size_t s = 0; s < app->sent_count; ++s) app->sent[s].output = (uint32_t)map[app->sent[s].output]; + memcpy(app->last_sent, last, sizeof(last)); + memcpy(app->saved_sent, saved, sizeof(saved)); + return PURE_OK; +} + +PURE_COLD static PureResult open_module(PureApp *app, const PureModule *module) { + const PureModule *old = app->module; + bool stored = pure_save_enabled(app); + double values[PURE_MODULE_STATES] = {0}; + PureDraft *texts[PURE_MODULE_STATES] = {0}, *list_drafts[PURE_MODULE_STATES] = {0}; + PureList *lists[PURE_MODULE_STATES] = {0}; + PureVersion saved[PURE_MODULE_STATES] = {{0, 0}}, before[PURE_MODULE_STATES] = {{0, 0}}; + int kept[PURE_MODULE_STATES]; + bool rewrite[PURE_MODULE_STATES] = {false}; + PureResult result = PURE_OK; + for (uint32_t i = 0; i < module->states; ++i) { + int previous = old ? pure_module_state(old, module->state_names[i]) : -1; + kept[i] = previous >= 0 && old->state_type[previous] == module->state_type[i] ? previous : -1; + if (kept[i] >= 0) saved[i] = app->saved[kept[i]]; + if (module->state_type[i] == PURE_STATE_TEXT) { + if (kept[i] >= 0) texts[i] = app->texts[kept[i]]; + else if (result == PURE_OK) + result = stored ? pure_save_open_text(app, module, i, &texts[i], &saved[i]) : + new_text(&texts[i], module, module->state_ref[i]); + } else if (module->state_type[i] == PURE_STATE_LIST) { + if (result != PURE_OK) continue; + if (kept[i] >= 0) { + result = keep_list(&lists[i], app->lists[kept[i]], old, old->state_ref[kept[i]], module, + module->state_ref[i]); + list_drafts[i] = app->list_drafts[kept[i]]; + rewrite[i] = result == PURE_OK && list_drafts[i] && lists[i] != app->lists[kept[i]]; + } else if (stored) { + result = pure_save_open_list(app, module, i, &lists[i], &list_drafts[i], &saved[i]); + } else if (!(lists[i] = new_list(module, module->state_ref[i]))) result = PURE_ALLOCATION; + } else values[i] = kept[i] >= 0 ? app->values[kept[i]] : module->initial[i]; + } + /* A keyed list keeps its items in key order: one that was not keyed, or + * keyed by another field, is put in order and its indices follow their + * items. Two items with one key refuse the module: nothing is dropped. */ + size_t *moved[PURE_MODULE_STATES] = {0}; + for (uint32_t i = 0; i < module->states && result == PURE_OK; ++i) { + if (module->state_type[i] != PURE_STATE_LIST || !module->state_key[i]) continue; + size_t count = pure_list_count(lists[i]); + PureList *sorted = NULL; + if (count && !(moved[i] = malloc(count * sizeof(**moved)))) result = PURE_ALLOCATION; + else result = pure_list_sorted(lists[i], module->state_key[i] - 1u, &sorted, moved[i]); + if (!sorted) { + free(moved[i]); + moved[i] = NULL; + continue; + } + if (kept[i] < 0 || lists[i] != app->lists[kept[i]]) pure_list_free(lists[i]); + lists[i] = sorted; + rewrite[i] = list_drafts[i] != NULL; + } + /* A cursor or index keeps its position only while its text or list is the + * one it belonged to. */ + for (uint32_t i = 0; i < module->states; ++i) { + if (module->state_type[i] != PURE_STATE_CURSOR && module->state_type[i] != PURE_STATE_INDEX) continue; + uint32_t owner = module->state_ref[i]; + bool same = kept[i] >= 0 && kept[owner] >= 0 && old->state_ref[kept[i]] == (unsigned)kept[owner]; + values[i] = same ? app->values[kept[i]] : 0; + } + if (result == PURE_OK && stored) result = pure_save_open_values(app, module, values, kept, texts, lists); + /* Outputs keep their sends and numbers by name. */ + if (result == PURE_OK) result = old ? remap_outputs(app, old, module, false) : stored ? pure_save_open_links(app, module) : PURE_OK; + for (uint32_t i = 0; i < module->states; ++i) { + uint32_t list = module->state_ref[i]; + if (module->state_type[i] == PURE_STATE_INDEX && moved[list] && values[i] < (double)pure_list_count(lists[list])) + values[i] = (double)moved[list][(size_t)values[i]]; + } + for (uint32_t i = 0; i < module->states; ++i) free(moved[i]); + /* Store the lists whose record or order changed last, so that a failure + * can put every draft back as it was. */ + for (uint32_t i = 0; i < module->states; ++i) + if (rewrite[i]) { + before[i] = pure_draft_version(list_drafts[i]); + pure_draft_hold(list_drafts[i], true); + } + for (uint32_t i = 0; i < module->states && result == PURE_OK; ++i) + if (rewrite[i]) result = pure_save_rewrite_list(module, i, lists[i], list_drafts[i]); + for (uint32_t i = 0; i < module->states; ++i) + if (rewrite[i]) { + if (result != PURE_OK) pure_draft_restore(list_drafts[i], before[i]); + pure_draft_hold(list_drafts[i], false); + } + if (result != PURE_OK) { + for (uint32_t i = 0; i < module->states; ++i) { + if (kept[i] >= 0) { + if (lists[i] && lists[i] != app->lists[kept[i]]) pure_list_free(lists[i]); + continue; + } + pure_draft_close(texts[i]); + pure_list_free(lists[i]); + pure_draft_close(list_drafts[i]); + } + return result; + } + for (uint32_t i = 0; old && i < old->states; ++i) { + bool reused = false, draft_reused = false; + for (uint32_t k = 0; k < module->states; ++k) { + reused = reused || (texts[k] && texts[k] == app->texts[i]) || (lists[k] && lists[k] == app->lists[i]); + draft_reused = draft_reused || (list_drafts[k] && list_drafts[k] == app->list_drafts[i]); + } + if (!reused) { + pure_draft_close(app->texts[i]); + pure_list_free(app->lists[i]); + } + if (!draft_reused) pure_draft_close(app->list_drafts[i]); + } + memcpy(app->values, values, sizeof(values)); + memcpy(app->texts, texts, sizeof(texts)); + memcpy(app->lists, lists, sizeof(lists)); + memcpy(app->list_drafts, list_drafts, sizeof(list_drafts)); + memcpy(app->saved, saved, sizeof(saved)); + if (old) remap_outputs(app, old, module, true); + app->module = module; + ++app->changes; + return PURE_OK; +} + +PURE_COLD PureResult pure_app_start(PureApp *app, const PureModule *module, PureData data) { + *app = (PureApp){.data = data, .fault_pc = UINT32_MAX}; + PureResult result = open_module(app, module); + if (result == PURE_OK) result = pure_app_save(app); + if (result != PURE_OK) pure_app_stop(app); + return result; +} + +PURE_COLD PureResult pure_app_replace(PureApp *app, const PureModule *module) { + pure_app_finish(app); + if (app->open || app->pending_count) { + PureResult saved = pure_app_save(app); /* the burst belongs to the module that made it */ + if (saved != PURE_OK) return saved; + } + return open_module(app, module); +} -- cgit v1.2.3