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