diff options
Diffstat (limited to 'json-writer.c')
| -rw-r--r-- | json-writer.c | 414 |
1 files changed, 414 insertions, 0 deletions
diff --git a/json-writer.c b/json-writer.c new file mode 100644 index 0000000..aadb9db --- /dev/null +++ b/json-writer.c @@ -0,0 +1,414 @@ +#include "cache.h" +#include "json-writer.h" + +void jw_init(struct json_writer *jw) +{ + strbuf_init(&jw->json, 0); + strbuf_init(&jw->open_stack, 0); + jw->need_comma = 0; + jw->pretty = 0; +} + +void jw_release(struct json_writer *jw) +{ + strbuf_release(&jw->json); + strbuf_release(&jw->open_stack); +} + +/* + * Append JSON-quoted version of the given string to 'out'. + */ +static void append_quoted_string(struct strbuf *out, const char *in) +{ + unsigned char c; + + strbuf_addch(out, '"'); + while ((c = *in++) != '\0') { + if (c == '"') + strbuf_addstr(out, "\\\""); + else if (c == '\\') + strbuf_addstr(out, "\\\\"); + else if (c == '\n') + strbuf_addstr(out, "\\n"); + else if (c == '\r') + strbuf_addstr(out, "\\r"); + else if (c == '\t') + strbuf_addstr(out, "\\t"); + else if (c == '\f') + strbuf_addstr(out, "\\f"); + else if (c == '\b') + strbuf_addstr(out, "\\b"); + else if (c < 0x20) + strbuf_addf(out, "\\u%04x", c); + else + strbuf_addch(out, c); + } + strbuf_addch(out, '"'); +} + +static void indent_pretty(struct json_writer *jw) +{ + int k; + + for (k = 0; k < jw->open_stack.len; k++) + strbuf_addstr(&jw->json, " "); +} + +/* + * Begin an object or array (either top-level or nested within the currently + * open object or array). + */ +static void begin(struct json_writer *jw, char ch_open, int pretty) +{ + jw->pretty = pretty; + + strbuf_addch(&jw->json, ch_open); + + strbuf_addch(&jw->open_stack, ch_open); + jw->need_comma = 0; +} + +/* + * Assert that the top of the open-stack is an object. + */ +static void assert_in_object(const struct json_writer *jw, const char *key) +{ + if (!jw->open_stack.len) + BUG("json-writer: object: missing jw_object_begin(): '%s'", key); + if (jw->open_stack.buf[jw->open_stack.len - 1] != '{') + BUG("json-writer: object: not in object: '%s'", key); +} + +/* + * Assert that the top of the open-stack is an array. + */ +static void assert_in_array(const struct json_writer *jw) +{ + if (!jw->open_stack.len) + BUG("json-writer: array: missing jw_array_begin()"); + if (jw->open_stack.buf[jw->open_stack.len - 1] != '[') + BUG("json-writer: array: not in array"); +} + +/* + * Add comma if we have already seen a member at this level. + */ +static void maybe_add_comma(struct json_writer *jw) +{ + if (jw->need_comma) + strbuf_addch(&jw->json, ','); + else + jw->need_comma = 1; +} + +static void fmt_double(struct json_writer *jw, int precision, + double value) +{ + if (precision < 0) { + strbuf_addf(&jw->json, "%f", value); + } else { + struct strbuf fmt = STRBUF_INIT; + strbuf_addf(&fmt, "%%.%df", precision); + strbuf_addf(&jw->json, fmt.buf, value); + strbuf_release(&fmt); + } +} + +static void object_common(struct json_writer *jw, const char *key) +{ + assert_in_object(jw, key); + maybe_add_comma(jw); + + if (jw->pretty) { + strbuf_addch(&jw->json, '\n'); + indent_pretty(jw); + } + + append_quoted_string(&jw->json, key); + strbuf_addch(&jw->json, ':'); + if (jw->pretty) + strbuf_addch(&jw->json, ' '); +} + +static void array_common(struct json_writer *jw) +{ + assert_in_array(jw); + maybe_add_comma(jw); + + if (jw->pretty) { + strbuf_addch(&jw->json, '\n'); + indent_pretty(jw); + } +} + +/* + * Assert that the given JSON object or JSON array has been properly + * terminated. (Has closing bracket.) + */ +static void assert_is_terminated(const struct json_writer *jw) +{ + if (jw->open_stack.len) + BUG("json-writer: object: missing jw_end(): '%s'", + jw->json.buf); +} + +void jw_object_begin(struct json_writer *jw, int pretty) +{ + begin(jw, '{', pretty); +} + +void jw_object_string(struct json_writer *jw, const char *key, const char *value) +{ + object_common(jw, key); + append_quoted_string(&jw->json, value); +} + +void jw_object_intmax(struct json_writer *jw, const char *key, intmax_t value) +{ + object_common(jw, key); + strbuf_addf(&jw->json, "%"PRIdMAX, value); +} + +void jw_object_double(struct json_writer *jw, const char *key, int precision, + double value) +{ + object_common(jw, key); + fmt_double(jw, precision, value); +} + +void jw_object_true(struct json_writer *jw, const char *key) +{ + object_common(jw, key); + strbuf_addstr(&jw->json, "true"); +} + +void jw_object_false(struct json_writer *jw, const char *key) +{ + object_common(jw, key); + strbuf_addstr(&jw->json, "false"); +} + +void jw_object_bool(struct json_writer *jw, const char *key, int value) +{ + if (value) + jw_object_true(jw, key); + else + jw_object_false(jw, key); +} + +void jw_object_null(struct json_writer *jw, const char *key) +{ + object_common(jw, key); + strbuf_addstr(&jw->json, "null"); +} + +static void increase_indent(struct strbuf *sb, + const struct json_writer *jw, + int indent) +{ + int k; + + strbuf_reset(sb); + for (k = 0; k < jw->json.len; k++) { + char ch = jw->json.buf[k]; + strbuf_addch(sb, ch); + if (ch == '\n') + strbuf_addchars(sb, ' ', indent); + } +} + +static void kill_indent(struct strbuf *sb, + const struct json_writer *jw) +{ + int k; + int eat_it = 0; + + strbuf_reset(sb); + for (k = 0; k < jw->json.len; k++) { + char ch = jw->json.buf[k]; + if (eat_it && ch == ' ') + continue; + if (ch == '\n') { + eat_it = 1; + continue; + } + eat_it = 0; + strbuf_addch(sb, ch); + } +} + +static void append_sub_jw(struct json_writer *jw, + const struct json_writer *value) +{ + /* + * If both are pretty, increase the indentation of the sub_jw + * to better fit under the super. + * + * If the super is pretty, but the sub_jw is compact, leave the + * sub_jw compact. (We don't want to parse and rebuild the sub_jw + * for this debug-ish feature.) + * + * If the super is compact, and the sub_jw is pretty, convert + * the sub_jw to compact. + * + * If both are compact, keep the sub_jw compact. + */ + if (jw->pretty && jw->open_stack.len && value->pretty) { + struct strbuf sb = STRBUF_INIT; + increase_indent(&sb, value, jw->open_stack.len * 2); + strbuf_addbuf(&jw->json, &sb); + strbuf_release(&sb); + return; + } + if (!jw->pretty && value->pretty) { + struct strbuf sb = STRBUF_INIT; + kill_indent(&sb, value); + strbuf_addbuf(&jw->json, &sb); + strbuf_release(&sb); + return; + } + + strbuf_addbuf(&jw->json, &value->json); +} + +/* + * Append existing (properly terminated) JSON sub-data (object or array) + * as-is onto the given JSON data. + */ +void jw_object_sub_jw(struct json_writer *jw, const char *key, + const struct json_writer *value) +{ + assert_is_terminated(value); + + object_common(jw, key); + append_sub_jw(jw, value); +} + +void jw_object_inline_begin_object(struct json_writer *jw, const char *key) +{ + object_common(jw, key); + + jw_object_begin(jw, jw->pretty); +} + +void jw_object_inline_begin_array(struct json_writer *jw, const char *key) +{ + object_common(jw, key); + + jw_array_begin(jw, jw->pretty); +} + +void jw_array_begin(struct json_writer *jw, int pretty) +{ + begin(jw, '[', pretty); +} + +void jw_array_string(struct json_writer *jw, const char *value) +{ + array_common(jw); + append_quoted_string(&jw->json, value); +} + +void jw_array_intmax(struct json_writer *jw, intmax_t value) +{ + array_common(jw); + strbuf_addf(&jw->json, "%"PRIdMAX, value); +} + +void jw_array_double(struct json_writer *jw, int precision, double value) +{ + array_common(jw); + fmt_double(jw, precision, value); +} + +void jw_array_true(struct json_writer *jw) +{ + array_common(jw); + strbuf_addstr(&jw->json, "true"); +} + +void jw_array_false(struct json_writer *jw) +{ + array_common(jw); + strbuf_addstr(&jw->json, "false"); +} + +void jw_array_bool(struct json_writer *jw, int value) +{ + if (value) + jw_array_true(jw); + else + jw_array_false(jw); +} + +void jw_array_null(struct json_writer *jw) +{ + array_common(jw); + strbuf_addstr(&jw->json, "null"); +} + +void jw_array_sub_jw(struct json_writer *jw, const struct json_writer *value) +{ + assert_is_terminated(value); + + array_common(jw); + append_sub_jw(jw, value); +} + +void jw_array_argc_argv(struct json_writer *jw, int argc, const char **argv) +{ + int k; + + for (k = 0; k < argc; k++) + jw_array_string(jw, argv[k]); +} + +void jw_array_argv(struct json_writer *jw, const char **argv) +{ + while (*argv) + jw_array_string(jw, *argv++); +} + +void jw_array_inline_begin_object(struct json_writer *jw) +{ + array_common(jw); + + jw_object_begin(jw, jw->pretty); +} + +void jw_array_inline_begin_array(struct json_writer *jw) +{ + array_common(jw); + + jw_array_begin(jw, jw->pretty); +} + +int jw_is_terminated(const struct json_writer *jw) +{ + return !jw->open_stack.len; +} + +void jw_end(struct json_writer *jw) +{ + char ch_open; + int len; + + if (!jw->open_stack.len) + BUG("json-writer: too many jw_end(): '%s'", jw->json.buf); + + len = jw->open_stack.len - 1; + ch_open = jw->open_stack.buf[len]; + + strbuf_setlen(&jw->open_stack, len); + jw->need_comma = 1; + + if (jw->pretty) { + strbuf_addch(&jw->json, '\n'); + indent_pretty(jw); + } + + if (ch_open == '{') + strbuf_addch(&jw->json, '}'); + else + strbuf_addch(&jw->json, ']'); +} |