blobmsg_json.c

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/*
 * Copyright (C) 2010-2012 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.
 */
#include <inttypes.h>
#include "blobmsg.h"
#include "blobmsg_json.h"
 
#ifdef JSONC
        #include <json.h>
#else
        #include <json/json.h>
#endif
 
bool blobmsg_add_object(struct blob_buf *b, json_object *obj)
{
        json_object_object_foreach(obj, key, val) {
                if (!blobmsg_add_json_element(b, key, val))
                        return false;
        }
        return true;
}
 
static bool blobmsg_add_array(struct blob_buf *b, struct array_list *a)
{
        int i, len;
 
        for (i = 0, len = array_list_length(a); i < len; i++) {
                if (!blobmsg_add_json_element(b, NULL, array_list_get_idx(a, i)))
                        return false;
        }
 
        return true;
}
 
bool blobmsg_add_json_element(struct blob_buf *b, const char *name, json_object *obj)
{
        bool ret = true;
        void *c;
 
        switch (json_object_get_type(obj)) {
        case json_type_object:
                c = blobmsg_open_table(b, name);
                ret = blobmsg_add_object(b, obj);
                blobmsg_close_table(b, c);
                break;
        case json_type_array:
                c = blobmsg_open_array(b, name);
                ret = blobmsg_add_array(b, json_object_get_array(obj));
                blobmsg_close_array(b, c);
                break;
        case json_type_string:
                blobmsg_add_string(b, name, json_object_get_string(obj));
                break;
        case json_type_boolean:
                blobmsg_add_u8(b, name, json_object_get_boolean(obj));
                break;
        case json_type_int: {
                int64_t i64 = json_object_get_int64(obj);
                if (i64 >= INT32_MIN && i64 <= INT32_MAX) {
                        blobmsg_add_u32(b, name, (uint32_t)i64);
                } else {
                        blobmsg_add_u64(b, name, (uint64_t)i64);
                }
                break;
        }
        case json_type_double:
                blobmsg_add_double(b, name, json_object_get_double(obj));
                break;
        case json_type_null:
                blobmsg_add_field(b, BLOBMSG_TYPE_UNSPEC, name, NULL, 0);
                break;
        default:
                return false;
        }
        return ret;
}
 
static bool __blobmsg_add_json(struct blob_buf *b, json_object *obj)
{
        bool ret = false;
 
        if (!obj)
                return false;
 
        if (json_object_get_type(obj) != json_type_object)
                goto out;
 
        ret = blobmsg_add_object(b, obj);
 
out:
        json_object_put(obj);
        return ret;
}
 
bool blobmsg_add_json_from_file(struct blob_buf *b, const char *file)
{
        return __blobmsg_add_json(b, json_object_from_file(file));
}
 
bool blobmsg_add_json_from_string(struct blob_buf *b, const char *str)
{
        return __blobmsg_add_json(b, json_tokener_parse(str));
}
 
 
struct strbuf {
        int len;
        int pos;
        char *buf;
 
        blobmsg_json_format_t custom_format;
        void *priv;
        bool indent;
        int indent_level;
};
 
static bool blobmsg_puts(struct strbuf *s, const char *c, int len)
{
        size_t new_len;
        char *new_buf;
 
        if (len <= 0)
                return true;
 
        if (s->pos + len >= s->len) {
                new_len = s->len + 16 + len;
                new_buf = realloc(s->buf, new_len);
                if (!new_buf)
                        return false;
 
                s->len = new_len;
                s->buf = new_buf;
        }
 
        memcpy(s->buf + s->pos, c, len);
        s->pos += len;
        return true;
}
 
static void add_separator(struct strbuf *s)
{
        const char indent_chars[] = "\n\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t\t";
        size_t len;
 
        if (!s->indent)
                return;
 
        len = s->indent_level + 1;
        if (len > sizeof(indent_chars) - 1)
                len = sizeof(indent_chars) - 1;
 
        blobmsg_puts(s, indent_chars, len);
}
 
 
static void blobmsg_format_string(struct strbuf *s, const char *str)
{
        const unsigned char *p, *last, *end;
        char buf[8] = "\\u00";
 
        end = (unsigned char *) str + strlen(str);
        blobmsg_puts(s, "\"", 1);
        for (p = (unsigned char *) str, last = p; *p; p++) {
                char escape = '\0';
                int len;
 
                switch(*p) {
                case '\b':
                        escape = 'b';
                        break;
                case '\n':
                        escape = 'n';
                        break;
                case '\t':
                        escape = 't';
                        break;
                case '\r':
                        escape = 'r';
                        break;
                case '"':
                case '\\':
                        escape = *p;
                        break;
                default:
                        if (*p < ' ')
                                escape = 'u';
                        break;
                }
 
                if (!escape)
                        continue;
 
                if (p > last)
                        blobmsg_puts(s, (char *) last, p - last);
                last = p + 1;
                buf[1] = escape;
 
                if (escape == 'u') {
                        snprintf(buf + 4, sizeof(buf) - 4, "%02x", (unsigned char) *p);
                        len = 6;
                } else {
                        len = 2;
                }
                blobmsg_puts(s, buf, len);
        }
 
        blobmsg_puts(s, (char *) last, end - last);
        blobmsg_puts(s, "\"", 1);
}
 
static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array);
 
static void blobmsg_format_element(struct strbuf *s, struct blob_attr *attr, bool without_name, bool head)
{
        const char *data_str;
        char buf[317];
        void *data;
        int len;
 
        if (!blobmsg_check_attr(attr, false))
                return;
 
        if (!without_name && blobmsg_name(attr)[0]) {
                blobmsg_format_string(s, blobmsg_name(attr));
                blobmsg_puts(s, ": ", s->indent ? 2 : 1);
        }
 
        data = blobmsg_data(attr);
        len = blobmsg_data_len(attr);
 
        if (!head && s->custom_format) {
                data_str = s->custom_format(s->priv, attr);
                if (data_str)
                        goto out;
        }
 
        data_str = buf;
        switch(blob_id(attr)) {
        case BLOBMSG_TYPE_UNSPEC:
                snprintf(buf, sizeof(buf), "null");
                break;
        case BLOBMSG_TYPE_BOOL:
                snprintf(buf, sizeof(buf), "%s", *(uint8_t *)data ? "true" : "false");
                break;
        case BLOBMSG_TYPE_INT16:
                snprintf(buf, sizeof(buf), "%" PRId16, (int16_t) be16_to_cpu(*(uint16_t *)data));
                break;
        case BLOBMSG_TYPE_INT32:
                snprintf(buf, sizeof(buf), "%" PRId32, (int32_t) be32_to_cpu(*(uint32_t *)data));
                break;
        case BLOBMSG_TYPE_INT64:
                snprintf(buf, sizeof(buf), "%" PRId64, (int64_t) be64_to_cpu(*(uint64_t *)data));
                break;
        case BLOBMSG_TYPE_DOUBLE:
                snprintf(buf, sizeof(buf), "%lf", blobmsg_get_double(attr));
                break;
        case BLOBMSG_TYPE_STRING:
                blobmsg_format_string(s, data);
                return;
        case BLOBMSG_TYPE_ARRAY:
                blobmsg_format_json_list(s, data, len, true);
                return;
        case BLOBMSG_TYPE_TABLE:
                blobmsg_format_json_list(s, data, len, false);
                return;
        }
 
out:
        blobmsg_puts(s, data_str, strlen(data_str));
}
 
static void blobmsg_format_json_list(struct strbuf *s, struct blob_attr *attr, int len, bool array)
{
        struct blob_attr *pos;
        bool first = true;
        size_t rem = len;
 
        blobmsg_puts(s, (array ? "[" : "{" ), 1);
        s->indent_level++;
        add_separator(s);
        __blob_for_each_attr(pos, attr, rem) {
                if (!first) {
                        blobmsg_puts(s, ",", 1);
                        add_separator(s);
                }
 
                blobmsg_format_element(s, pos, array, false);
                first = false;
        }
        s->indent_level--;
        add_separator(s);
        blobmsg_puts(s, (array ? "]" : "}"), 1);
}
 
static void setup_strbuf(struct strbuf *s, struct blob_attr *attr, blobmsg_json_format_t cb, void *priv, int indent)
{
        s->len = blob_len(attr);
        s->buf = malloc(s->len);
        s->pos = 0;
        s->custom_format = cb;
        s->priv = priv;
        s->indent = false;
 
        if (indent >= 0) {
                s->indent = true;
                s->indent_level = indent;
        }
}
 
char *blobmsg_format_json_with_cb(struct blob_attr *attr, bool list, blobmsg_json_format_t cb, void *priv, int indent)
{
        struct strbuf s = {0};
        bool array;
        char *ret;
 
        setup_strbuf(&s, attr, cb, priv, indent);
        if (!s.buf)
                return NULL;
 
        array = blob_is_extended(attr) &&
                blobmsg_type(attr) == BLOBMSG_TYPE_ARRAY;
 
        if (list)
                blobmsg_format_json_list(&s, blobmsg_data(attr), blobmsg_data_len(attr), array);
        else
                blobmsg_format_element(&s, attr, false, false);
 
        if (!s.len) {
                free(s.buf);
                return NULL;
        }
 
        ret = realloc(s.buf, s.pos + 1);
        if (!ret) {
                free(s.buf);
                return NULL;
        }
 
        ret[s.pos] = 0;
 
        return ret;
}
 
char *blobmsg_format_json_value_with_cb(struct blob_attr *attr, blobmsg_json_format_t cb, void *priv, int indent)
{
        struct strbuf s = {0};
        char *ret;
 
        setup_strbuf(&s, attr, cb, priv, indent);
        if (!s.buf)
                return NULL;
 
        blobmsg_format_element(&s, attr, true, false);
 
        if (!s.len) {
                free(s.buf);
                return NULL;
        }
 
        ret = realloc(s.buf, s.pos + 1);
        if (!ret) {
                free(s.buf);
                return NULL;
        }
 
        ret[s.pos] = 0;
 
        return ret;
}