diff options
Diffstat (limited to 'src/libmowgli/ext/json.h')
| -rw-r--r-- | src/libmowgli/ext/json.h | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/src/libmowgli/ext/json.h b/src/libmowgli/ext/json.h new file mode 100644 index 0000000..247018a --- /dev/null +++ b/src/libmowgli/ext/json.h @@ -0,0 +1,151 @@ +/* + * Copyright (C) 2012 Alex Iadicicco + * Rights to this code are as documented in COPYING. + * + * Structs and functions for interacting with JSON documents from C + */ + +/* A note about refcounting: + + Since JSON cannot represent recursive structures, it makes sense + to use refcounting. If a recursive structure is created then it's + guaranteed to be the programmer's fault, and the programmer deserves + every memory leak he gets. + + When cared for and fed daily, refcounting is a very nifty tool. Entire + structures can be destroyed cleanly by a single mowgli_json_decref. To + fully take advantage of this, know the refcounting rules: + + o JSON objects as arguments should NEVER have a reference for + the callee. If the callee wants to keep the object somewhere, + they will incref themselves. + + o When returning a JSON object, be sure to leave a single reference + for the caller. (If you tried to decref before returning, you + could potentially drop the refcount to zero.) + + o Newly created structures are the sole exception to the previous + rule. This is because it is useful to be able to use constructors + as arguments to functions as follows: + mowgli_json_object_add(obj, "sum", mowgli_json_create_integer(10)); + Note that this ONLY applies to the mowgli_json_create_* + constructors provided by mowgli.json. The typical case of + assigning a new structure to a variable name then looks like this: + my_integer = mowgli_json_incref(mowgli_json_create_integer(0)); + + Since failure to pay attention to reference counts will cause memory + problems, *always double check your reference counting*! + + --aji */ + +#ifndef MOWGLI_JSON_H +#define MOWGLI_JSON_H + +/* Types with public definitons */ +typedef enum +{ + MOWGLI_JSON_TAG_NULL, + MOWGLI_JSON_TAG_BOOLEAN, + + /* JSON does not distinguish between integers or floating points + (they are both just number types), but in C we are forced to + make the distinction */ + MOWGLI_JSON_TAG_INTEGER, + MOWGLI_JSON_TAG_FLOAT, + MOWGLI_JSON_TAG_STRING, + MOWGLI_JSON_TAG_ARRAY, + MOWGLI_JSON_TAG_OBJECT, +} mowgli_json_tag_t; +typedef struct _mowgli_json_t mowgli_json_t; + +/* Types whose definitons are kept private */ +typedef struct _mowgli_json_parse_t mowgli_json_parse_t; + +struct _mowgli_json_t +{ + mowgli_json_tag_t tag; + int refcount; + + union + { + bool v_bool; + int v_int; + double v_float; + mowgli_string_t *v_string; + mowgli_list_t *v_array; + mowgli_patricia_t *v_object; + } v; +}; + +/* Helper macros useful for cleanly interacting with mowgli_json_t + structs. These are just helpers and are not intended to provide a + consistent interface. They are as likely to change as the mowgli_json_t + struct itself. */ +#define MOWGLI_JSON_TAG(n) ((n)->tag) +#define MOWGLI_JSON_BOOLEAN(n) ((n)->v.v_bool) +#define MOWGLI_JSON_INTEGER(n) ((n)->v.v_int) +#define MOWGLI_JSON_FLOAT(n) ((n)->v.v_float) +#define MOWGLI_JSON_NUMBER(n) ((n)->tag == MOWGLI_JSON_TAG_FLOAT ? \ + (n)->v.v_float : (n)->v.v_int) +#define MOWGLI_JSON_STRING(n) ((n)->v.v_string) +#define MOWGLI_JSON_STRING_STR(n) ((n)->v.v_string->str) +#define MOWGLI_JSON_STRING_LEN(n) ((n)->v.v_string->pos) +#define MOWGLI_JSON_ARRAY(n) ((n)->v.v_array) +#define MOWGLI_JSON_OBJECT(n) ((n)->v.v_object) + +/* Users of the JSON parser/formatter are not required to use these + constants, but the parser will ALWAYS parse the symbols "null", + "true", and "false" into these constants */ +extern mowgli_json_t *mowgli_json_null; +extern mowgli_json_t *mowgli_json_true; +extern mowgli_json_t *mowgli_json_false; + +/* These simply return the node argument. If the node was destroyed, + the return value will be NULL. Note that in all other cases (invalid + refcount, unknown type, etc.) the node will be returned untouched */ +extern mowgli_json_t *mowgli_json_incref(mowgli_json_t *n); +extern mowgli_json_t *mowgli_json_decref(mowgli_json_t *n); + +extern mowgli_json_t *mowgli_json_create_integer(int v_int); +extern mowgli_json_t *mowgli_json_create_float(double v_float); + +/* #define mowgli_json_create_number(V) _Generic((V), \ + int: mowgli_json_create_integer, \ + double: mowgli_json_create_float)(V) */ +extern mowgli_json_t *mowgli_json_create_string_n(const char *str, size_t len); +extern mowgli_json_t *mowgli_json_create_string(const char *str); +extern mowgli_json_t *mowgli_json_create_array(void); +extern mowgli_json_t *mowgli_json_create_object(void); + +#include "json-inline.h" + +typedef struct _mowgli_json_output_t mowgli_json_output_t; + +struct _mowgli_json_output_t +{ + void (*append)(mowgli_json_output_t *out, const char *str, size_t len); + void (*append_char)(mowgli_json_output_t *out, const char c); + void *priv; +}; + +extern void mowgli_json_serialize(mowgli_json_t *n, mowgli_json_output_t *out, int pretty); +extern void mowgli_json_serialize_to_string(mowgli_json_t *n, mowgli_string_t *str, int pretty); + +/* extended parsing interface. The 'multidoc' parameter here indicates + whether we intend to parse multiple documents from a single data source + or not. If you are expecting exactly one complete JSON document, + indicate 'false'. */ +extern mowgli_json_parse_t *mowgli_json_parse_create(bool multidoc); +extern void mowgli_json_parse_destroy(mowgli_json_parse_t *parse); +extern void mowgli_json_parse_reset(mowgli_json_parse_t *parse, bool multidoc); +extern void mowgli_json_parse_data(mowgli_json_parse_t *parse, const char *data, size_t len); +extern char *mowgli_json_parse_error(mowgli_json_parse_t *parse); +extern bool mowgli_json_parse_more(mowgli_json_parse_t *parse); +extern mowgli_json_t *mowgli_json_parse_next(mowgli_json_parse_t *parse); + +/* Simple parsing interface. These expect the given data source to + represent exactly one complete JSON document */ +extern mowgli_json_t *mowgli_json_parse_file(const char *path); +extern mowgli_json_t *mowgli_json_parse_string(const char *data); + +#endif |