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1 | /* | |
2 | * A simple JSON writer | |
3 | * | |
4 | * Copyright Alexander Graf | |
5 | * | |
6 | * Authors: | |
7 | * Alexander Graf <[email protected]> | |
8 | * | |
9 | * This work is licensed under the terms of the GNU LGPL, version 2.1 or later. | |
10 | * See the COPYING.LIB file in the top-level directory. | |
11 | * | |
12 | */ | |
13 | ||
14 | /* | |
15 | * Type QJSON lets you build JSON text. Its interface mirrors (a | |
16 | * subset of) abstract JSON syntax. | |
17 | * | |
18 | * It does *not* detect incorrect use. It happily produces invalid | |
19 | * JSON then. This is what migration wants. | |
20 | * | |
21 | * QAPI output visitors also produce JSON text. However, they do | |
22 | * assert their preconditions and invariants, and therefore abort on | |
23 | * incorrect use. | |
24 | */ | |
25 | ||
26 | #include "qemu/osdep.h" | |
27 | #include "qapi/qmp/qstring.h" | |
28 | #include "qjson.h" | |
29 | ||
30 | struct QJSON { | |
31 | QString *str; | |
32 | bool omit_comma; | |
33 | }; | |
34 | ||
35 | static void json_emit_element(QJSON *json, const char *name) | |
36 | { | |
37 | /* Check whether we need to print a , before an element */ | |
38 | if (json->omit_comma) { | |
39 | json->omit_comma = false; | |
40 | } else { | |
41 | qstring_append(json->str, ", "); | |
42 | } | |
43 | ||
44 | if (name) { | |
45 | qstring_append(json->str, "\""); | |
46 | qstring_append(json->str, name); | |
47 | qstring_append(json->str, "\" : "); | |
48 | } | |
49 | } | |
50 | ||
51 | void json_start_object(QJSON *json, const char *name) | |
52 | { | |
53 | json_emit_element(json, name); | |
54 | qstring_append(json->str, "{ "); | |
55 | json->omit_comma = true; | |
56 | } | |
57 | ||
58 | void json_end_object(QJSON *json) | |
59 | { | |
60 | qstring_append(json->str, " }"); | |
61 | json->omit_comma = false; | |
62 | } | |
63 | ||
64 | void json_start_array(QJSON *json, const char *name) | |
65 | { | |
66 | json_emit_element(json, name); | |
67 | qstring_append(json->str, "[ "); | |
68 | json->omit_comma = true; | |
69 | } | |
70 | ||
71 | void json_end_array(QJSON *json) | |
72 | { | |
73 | qstring_append(json->str, " ]"); | |
74 | json->omit_comma = false; | |
75 | } | |
76 | ||
77 | void json_prop_int(QJSON *json, const char *name, int64_t val) | |
78 | { | |
79 | json_emit_element(json, name); | |
80 | qstring_append_int(json->str, val); | |
81 | } | |
82 | ||
83 | void json_prop_str(QJSON *json, const char *name, const char *str) | |
84 | { | |
85 | json_emit_element(json, name); | |
86 | qstring_append_chr(json->str, '"'); | |
87 | qstring_append(json->str, str); | |
88 | qstring_append_chr(json->str, '"'); | |
89 | } | |
90 | ||
91 | const char *qjson_get_str(QJSON *json) | |
92 | { | |
93 | return qstring_get_str(json->str); | |
94 | } | |
95 | ||
96 | QJSON *qjson_new(void) | |
97 | { | |
98 | QJSON *json = g_new0(QJSON, 1); | |
99 | ||
100 | json->str = qstring_from_str("{ "); | |
101 | json->omit_comma = true; | |
102 | return json; | |
103 | } | |
104 | ||
105 | void qjson_finish(QJSON *json) | |
106 | { | |
107 | json_end_object(json); | |
108 | } | |
109 | ||
110 | void qjson_destroy(QJSON *json) | |
111 | { | |
112 | qobject_unref(json->str); | |
113 | g_free(json); | |
114 | } |