Read JSON messages in message-json.c, for requests and answers alike

The in-place JSON reader of pure-serve's request bodies moves into its
own file with a small interface (pure_json_message, pure_json_fixed,
pure_json_space), so the delivery client can read an API's answers
with it. It gains a lenient mode for answers: a member that names no
field is skipped, value and all. Requests read as before.

1 files changed, 26 insertions, 0 deletions

diff --git a/prototypes/connections/message-json.h b/prototypes/connections/message-json.h
new file mode 100644
index 0000000..61211d6
--- /dev/null
+++ b/prototypes/connections/message-json.h
@@ -0,0 +1,26 @@
+#ifndef PURE_MESSAGE_JSON_H
+#define PURE_MESSAGE_JSON_H
+#include "module.h"
+
+/* A message's fields from a JSON object read in place (docs/research/082-json-in-place.md):
+ * a u32 or a number for a fixed field (put into the prefix), a string for
+ * bytes or text (left where it is: an escaped one is unescaped over itself,
+ * which never makes it longer), a group's fields as an object inside. */
+typedef struct {
+    const PureModule *module;
+    const PureInputShape *shape;
+    unsigned char *payload; /* the prefix; a string's start is counted from here */
+    unsigned char *table;   /* for each field, its start and size (u32le each) */
+    const bool *given;      /* fields given elsewhere (a request's query), or NULL */
+    bool lenient;           /* a member naming no field is skipped, value and all (an API's answer) */
+    bool seen[PURE_MODULE_FIELDS];
+} PureJsonMessage;
+
+/* The object at json[*at] (its opening brace), *at moved past it: NULL, or
+ * what is wrong ("json", "json_field": unknown or given twice, "json_type"). */
+const char *pure_json_message(PureJsonMessage *, unsigned char *json, size_t size, size_t *at);
+size_t pure_json_space(const unsigned char *json, size_t at, size_t size);
+/* A fixed field's value from its text (a query value or a JSON number) into
+ * the prefix: a u32 in range, or a finite number. */
+bool pure_json_fixed(const PureField *field, const unsigned char *text, size_t size, unsigned char *prefix);
+#endif