jshn: properly support JSON "null" type
[project/libubox.git] / json_script.h
1 /*
2 * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
3 *
4 * Permission to use, copy, modify, and/or distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16 #ifndef __JSON_SCRIPT_H
17 #define __JSON_SCRIPT_H
18
19 #include "avl.h"
20 #include "blob.h"
21 #include "blobmsg.h"
22 #include "utils.h"
23
24 struct json_script_file;
25
26 struct json_script_ctx {
27 struct avl_tree files;
28 struct blob_buf buf;
29
30 uint32_t run_seq;
31 bool abort;
32
33 /*
34 * handle_command: handle a command that was not recognized by the
35 * json_script core (required)
36 *
37 * @cmd: blobmsg container of the processed command
38 * @vars: blobmsg container of current run variables
39 */
40 void (*handle_command)(struct json_script_ctx *ctx, const char *name,
41 struct blob_attr *cmd, struct blob_attr *vars);
42
43 /*
44 * handle_expr: handle an expression that was not recognized by the
45 * json_script core (optional)
46 *
47 * @expr: blobmsg container of the processed expression
48 * @vars: blobmsg container of current runtime variables
49 */
50 int (*handle_expr)(struct json_script_ctx *ctx, const char *name,
51 struct blob_attr *expr, struct blob_attr *vars);
52
53 /*
54 * handle_var - look up a variable that's not part of the runtime
55 * variable set (optional)
56 */
57 const char *(*handle_var)(struct json_script_ctx *ctx, const char *name,
58 struct blob_attr *vars);
59
60 /*
61 * handle_file - load a file by filename (optional)
62 *
63 * in case of wildcards, it can return a chain of json_script files
64 * linked via the ::next pointer. Only the first json_script file is
65 * added to the tree.
66 */
67 struct json_script_file *(*handle_file)(struct json_script_ctx *ctx,
68 const char *name);
69
70 /*
71 * handle_error - handle a processing error in a command or expression
72 * (optional)
73 *
74 * @msg: error message
75 * @context: source file context of the error (blobmsg container)
76 */
77 void (*handle_error)(struct json_script_ctx *ctx, const char *msg,
78 struct blob_attr *context);
79 };
80
81 struct json_script_file {
82 struct avl_node avl;
83 struct json_script_file *next;
84
85 unsigned int seq;
86 struct blob_attr data[];
87 };
88
89 void json_script_init(struct json_script_ctx *ctx);
90 void json_script_free(struct json_script_ctx *ctx);
91
92 /*
93 * json_script_run - run a json script with a set of runtime variables
94 *
95 * @filename: initial filename to run
96 * @vars: blobmsg container of the current runtime variables
97 */
98 void json_script_run(struct json_script_ctx *ctx, const char *filename,
99 struct blob_attr *vars);
100
101 void json_script_run_file(struct json_script_ctx *ctx, struct json_script_file *file,
102 struct blob_attr *vars);
103
104 /*
105 * json_script_abort - abort current json script run
106 *
107 * to be called from a script context callback
108 */
109 static inline void
110 json_script_abort(struct json_script_ctx *ctx)
111 {
112 ctx->abort = true;
113 }
114
115 /*
116 * json_script_eval_string - evaluate a string and store the result
117 *
118 * Can be used to process variable references outside of a script
119 * in a same way that they would be interpreted in the script context.
120 */
121 int json_script_eval_string(struct json_script_ctx *ctx, struct blob_attr *vars,
122 struct blob_buf *buf, const char *name,
123 const char *pattern);
124
125 struct json_script_file *
126 json_script_file_from_blobmsg(const char *name, void *data, int len);
127
128 /*
129 * json_script_find_var - helper function to find a runtime variable from
130 * the list passed by json_script user.
131 * It is intended to be used by the .handle_var callback
132 */
133 const char *json_script_find_var(struct json_script_ctx *ctx, struct blob_attr *vars,
134 const char *name);
135
136 #endif