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Diffstat (limited to 'json-writer.h')
| -rw-r--r-- | json-writer.h | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/json-writer.h b/json-writer.h new file mode 100644 index 000000000000..83906b09c173 --- /dev/null +++ b/json-writer.h @@ -0,0 +1,107 @@ +#ifndef JSON_WRITER_H +#define JSON_WRITER_H + +/* + * JSON data structures are defined at: + * [1] http://www.ietf.org/rfc/rfc7159.txt + * [2] http://json.org/ + * + * The JSON-writer API allows one to build JSON data structures using a + * simple wrapper around a "struct strbuf" buffer. It is intended as a + * simple API to build output strings; it is not intended to be a general + * object model for JSON data. In particular, it does not re-order keys + * in an object (dictionary), it does not de-dup keys in an object, and + * it does not allow lookup or parsing of JSON data. + * + * All string values (both keys and string r-values) are properly quoted + * and escaped if they contain special characters. + * + * These routines create compact JSON data (with no unnecessary whitespace, + * newlines, or indenting). If you get an unexpected response, verify + * that you're not expecting a pretty JSON string. + * + * Both "JSON objects" (aka sets of k/v pairs) and "JSON array" can be + * constructed using a 'begin append* end' model. + * + * Nested objects and arrays can either be constructed bottom up (by + * creating sub object/arrays first and appending them to the super + * object/array) -or- by building them inline in one pass. This is a + * personal style and/or data shape choice. + * + * See t/helper/test-json-writer.c for various usage examples. + * + * LIMITATIONS: + * ============ + * + * The JSON specification [1,2] defines string values as Unicode data + * and probably UTF-8 encoded. The current json-writer API does not + * enforce this and will write any string as received. However, it will + * properly quote and backslash-escape them as necessary. It is up to + * the caller to UTF-8 encode their strings *before* passing them to this + * API. This layer should not have to try to guess the encoding or locale + * of the given strings. + */ + +#include "strbuf.h" + +struct json_writer +{ + /* + * Buffer of the in-progress JSON currently being composed. + */ + struct strbuf json; + + /* + * Simple stack of the currently open array and object forms. + * This is a string of '{' and '[' characters indicating the + * currently unterminated forms. This is used to ensure the + * properly closing character is used when popping a level and + * to know when the JSON is completely closed. + */ + struct strbuf open_stack; + + unsigned int need_comma:1; + unsigned int pretty:1; +}; + +#define JSON_WRITER_INIT { STRBUF_INIT, STRBUF_INIT, 0, 0 } + +void jw_init(struct json_writer *jw); +void jw_release(struct json_writer *jw); + +void jw_object_begin(struct json_writer *jw, int pretty); +void jw_array_begin(struct json_writer *jw, int pretty); + +void jw_object_string(struct json_writer *jw, const char *key, + const char *value); +void jw_object_intmax(struct json_writer *jw, const char *key, intmax_t value); +void jw_object_double(struct json_writer *jw, const char *key, int precision, + double value); +void jw_object_true(struct json_writer *jw, const char *key); +void jw_object_false(struct json_writer *jw, const char *key); +void jw_object_bool(struct json_writer *jw, const char *key, int value); +void jw_object_null(struct json_writer *jw, const char *key); +void jw_object_sub_jw(struct json_writer *jw, const char *key, + const struct json_writer *value); + +void jw_object_inline_begin_object(struct json_writer *jw, const char *key); +void jw_object_inline_begin_array(struct json_writer *jw, const char *key); + +void jw_array_string(struct json_writer *jw, const char *value); +void jw_array_intmax(struct json_writer *jw, intmax_t value); +void jw_array_double(struct json_writer *jw, int precision, double value); +void jw_array_true(struct json_writer *jw); +void jw_array_false(struct json_writer *jw); +void jw_array_bool(struct json_writer *jw, int value); +void jw_array_null(struct json_writer *jw); +void jw_array_sub_jw(struct json_writer *jw, const struct json_writer *value); +void jw_array_argc_argv(struct json_writer *jw, int argc, const char **argv); +void jw_array_argv(struct json_writer *jw, const char **argv); + +void jw_array_inline_begin_object(struct json_writer *jw); +void jw_array_inline_begin_array(struct json_writer *jw); + +int jw_is_terminated(const struct json_writer *jw); +void jw_end(struct json_writer *jw); + +#endif /* JSON_WRITER_H */ |