Makefile: add a hdr-check target
[git/git.git] / json-writer.h
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1#ifndef JSON_WRITER_H
2#define JSON_WRITER_H
3
4/*
5 * JSON data structures are defined at:
6 * [1] http://www.ietf.org/rfc/rfc7159.txt
7 * [2] http://json.org/
8 *
9 * The JSON-writer API allows one to build JSON data structures using a
10 * simple wrapper around a "struct strbuf" buffer. It is intended as a
11 * simple API to build output strings; it is not intended to be a general
12 * object model for JSON data. In particular, it does not re-order keys
13 * in an object (dictionary), it does not de-dup keys in an object, and
14 * it does not allow lookup or parsing of JSON data.
15 *
16 * All string values (both keys and string r-values) are properly quoted
17 * and escaped if they contain special characters.
18 *
19 * These routines create compact JSON data (with no unnecessary whitespace,
20 * newlines, or indenting). If you get an unexpected response, verify
21 * that you're not expecting a pretty JSON string.
22 *
23 * Both "JSON objects" (aka sets of k/v pairs) and "JSON array" can be
24 * constructed using a 'begin append* end' model.
25 *
26 * Nested objects and arrays can either be constructed bottom up (by
27 * creating sub object/arrays first and appending them to the super
28 * object/array) -or- by building them inline in one pass. This is a
29 * personal style and/or data shape choice.
30 *
31 * See t/helper/test-json-writer.c for various usage examples.
32 *
33 * LIMITATIONS:
34 * ============
35 *
36 * The JSON specification [1,2] defines string values as Unicode data
37 * and probably UTF-8 encoded. The current json-writer API does not
38 * enforce this and will write any string as received. However, it will
39 * properly quote and backslash-escape them as necessary. It is up to
40 * the caller to UTF-8 encode their strings *before* passing them to this
41 * API. This layer should not have to try to guess the encoding or locale
42 * of the given strings.
43 */
44
45struct json_writer
46{
47 /*
48 * Buffer of the in-progress JSON currently being composed.
49 */
50 struct strbuf json;
51
52 /*
53 * Simple stack of the currently open array and object forms.
54 * This is a string of '{' and '[' characters indicating the
55 * currently unterminated forms. This is used to ensure the
56 * properly closing character is used when popping a level and
57 * to know when the JSON is completely closed.
58 */
59 struct strbuf open_stack;
60
61 unsigned int need_comma:1;
62 unsigned int pretty:1;
63};
64
65#define JSON_WRITER_INIT { STRBUF_INIT, STRBUF_INIT, 0, 0 }
66
67void jw_init(struct json_writer *jw);
68void jw_release(struct json_writer *jw);
69
70void jw_object_begin(struct json_writer *jw, int pretty);
71void jw_array_begin(struct json_writer *jw, int pretty);
72
73void jw_object_string(struct json_writer *jw, const char *key,
74 const char *value);
75void jw_object_intmax(struct json_writer *jw, const char *key, intmax_t value);
76void jw_object_double(struct json_writer *jw, const char *key, int precision,
77 double value);
78void jw_object_true(struct json_writer *jw, const char *key);
79void jw_object_false(struct json_writer *jw, const char *key);
80void jw_object_bool(struct json_writer *jw, const char *key, int value);
81void jw_object_null(struct json_writer *jw, const char *key);
82void jw_object_sub_jw(struct json_writer *jw, const char *key,
83 const struct json_writer *value);
84
85void jw_object_inline_begin_object(struct json_writer *jw, const char *key);
86void jw_object_inline_begin_array(struct json_writer *jw, const char *key);
87
88void jw_array_string(struct json_writer *jw, const char *value);
89void jw_array_intmax(struct json_writer *jw, intmax_t value);
90void jw_array_double(struct json_writer *jw, int precision, double value);
91void jw_array_true(struct json_writer *jw);
92void jw_array_false(struct json_writer *jw);
93void jw_array_bool(struct json_writer *jw, int value);
94void jw_array_null(struct json_writer *jw);
95void jw_array_sub_jw(struct json_writer *jw, const struct json_writer *value);
96void jw_array_argc_argv(struct json_writer *jw, int argc, const char **argv);
97void jw_array_argv(struct json_writer *jw, const char **argv);
98
99void jw_array_inline_begin_object(struct json_writer *jw);
100void jw_array_inline_begin_array(struct json_writer *jw);
101
102int jw_is_terminated(const struct json_writer *jw);
103void jw_end(struct json_writer *jw);
104
105#endif /* JSON_WRITER_H */