1 | /* |
2 | * A simple JSON writer |
3 | * |
4 | * Copyright Alexander Graf |
5 | * |
6 | * Authors: |
7 | * Alexander Graf <agraf@suse.de> |
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 | } |
115 | |