json_script.h

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/*
 * Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#ifndef __JSON_SCRIPT_H
#define __JSON_SCRIPT_H
 
#include "avl.h"
#include "blob.h"
#include "blobmsg.h"
#include "utils.h"
 
struct json_script_file;
 
struct json_script_ctx {
        struct avl_tree files;
        struct blob_buf buf;
 
        uint32_t run_seq;
        bool abort;
 
        /*
         * handle_command: handle a command that was not recognized by the
         * json_script core (required)
         *
         * @cmd: blobmsg container of the processed command
         * @vars: blobmsg container of current run variables
         */
        void (*handle_command)(struct json_script_ctx *ctx, const char *name,
                               struct blob_attr *cmd, struct blob_attr *vars);
 
        /*
         * handle_expr: handle an expression that was not recognized by the
         * json_script core (optional)
         *
         * @expr: blobmsg container of the processed expression
         * @vars: blobmsg container of current runtime variables
         */
        int (*handle_expr)(struct json_script_ctx *ctx, const char *name,
                           struct blob_attr *expr, struct blob_attr *vars);
 
        /*
         * handle_var - look up a variable that's not part of the runtime
         * variable set (optional)
         */
        const char *(*handle_var)(struct json_script_ctx *ctx, const char *name,
                                  struct blob_attr *vars);
 
        /*
         * handle_file - load a file by filename (optional)
         *
         * in case of wildcards, it can return a chain of json_script files
         * linked via the ::next pointer. Only the first json_script file is
         * added to the tree.
         */
        struct json_script_file *(*handle_file)(struct json_script_ctx *ctx,
                                                const char *name);
 
        /*
         * handle_error - handle a processing error in a command or expression
         * (optional)
         * 
         * @msg: error message
         * @context: source file context of the error (blobmsg container)
         */
        void (*handle_error)(struct json_script_ctx *ctx, const char *msg,
                             struct blob_attr *context);
};
 
struct json_script_file {
        struct avl_node avl;
        struct json_script_file *next;
 
        unsigned int seq;
        struct blob_attr data[];
};
 
void json_script_init(struct json_script_ctx *ctx);
void json_script_free(struct json_script_ctx *ctx);
 
/*
 * json_script_run - run a json script with a set of runtime variables
 *
 * @filename: initial filename to run
 * @vars: blobmsg container of the current runtime variables
 */
void json_script_run(struct json_script_ctx *ctx, const char *filename,
                     struct blob_attr *vars);
 
void json_script_run_file(struct json_script_ctx *ctx, struct json_script_file *file,
                          struct blob_attr *vars);
 
/*
 * json_script_abort - abort current json script run
 *
 * to be called from a script context callback
 */
static inline void
json_script_abort(struct json_script_ctx *ctx)
{
        ctx->abort = true;
}
 
/*
 * json_script_eval_string - evaluate a string and store the result
 *
 * Can be used to process variable references outside of a script
 * in a same way that they would be interpreted in the script context.
 */
int json_script_eval_string(struct json_script_ctx *ctx, struct blob_attr *vars,
                            struct blob_buf *buf, const char *name,
                            const char *pattern);
 
struct json_script_file *
json_script_file_from_blobmsg(const char *name, void *data, int len);
 
/*
 * json_script_find_var - helper function to find a runtime variable from
 * the list passed by json_script user.
 * It is intended to be used by the .handle_var callback
 */
const char *json_script_find_var(struct json_script_ctx *ctx, struct blob_attr *vars,
                                 const char *name);
 
#endif