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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <string.h>
#include <stdlib.h>
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include "src/core/json/json.h"
#include "src/core/json/json_reader.h"
#include "src/core/json/json_writer.h"
/* The json reader will construct a bunch of grpc_json objects and
* link them all up together in a tree-like structure that will represent
* the json data in memory.
*
* It also uses its own input as a scratchpad to store all of the decoded,
* unescaped strings. So we need to keep track of all these pointers in
* that opaque structure the reader will carry for us.
*
* Note that this works because the act of parsing json always reduces its
* input size, and never expands it.
*/
typedef struct {
grpc_json *top;
grpc_json *current_container;
grpc_json *current_value;
gpr_uint8 *input;
gpr_uint8 *key;
gpr_uint8 *string;
gpr_uint8 *string_ptr;
size_t remaining_input;
} json_reader_userdata;
/* This json writer will put everything in a big string.
* The point is that we allocate that string in chunks of 256 bytes.
*/
typedef struct {
char *output;
size_t free_space;
size_t string_len;
size_t allocated;
} json_writer_userdata;
/* This function checks if there's enough space left in the output buffer,
* and will enlarge it if necessary. We're only allocating chunks of 256
* bytes at a time (or multiples thereof).
*/
static void json_writer_output_check(void *userdata, size_t needed) {
json_writer_userdata *state = userdata;
if (state->free_space >= needed) return;
needed -= state->free_space;
/* Round up by 256 bytes. */
needed = (needed + 0xff) & ~0xffU;
state->output = gpr_realloc(state->output, state->allocated + needed);
state->free_space += needed;
state->allocated += needed;
}
/* These are needed by the writer's implementation. */
static void json_writer_output_char(void *userdata, char c) {
json_writer_userdata *state = userdata;
json_writer_output_check(userdata, 1);
state->output[state->string_len++] = c;
state->free_space--;
}
static void json_writer_output_string_with_len(void *userdata, const char *str,
size_t len) {
json_writer_userdata *state = userdata;
json_writer_output_check(userdata, len);
memcpy(state->output + state->string_len, str, len);
state->string_len += len;
state->free_space -= len;
}
static void json_writer_output_string(void *userdata, const char *str) {
size_t len = strlen(str);
json_writer_output_string_with_len(userdata, str, len);
}
/* The reader asks us to clear our scratchpad. In our case, we'll simply mark
* the end of the current string, and advance our output pointer.
*/
static void json_reader_string_clear(void *userdata) {
json_reader_userdata *state = userdata;
if (state->string) {
GPR_ASSERT(state->string_ptr < state->input);
*state->string_ptr++ = 0;
}
state->string = state->string_ptr;
}
static void json_reader_string_add_char(void *userdata, gpr_uint32 c) {
json_reader_userdata *state = userdata;
GPR_ASSERT(state->string_ptr < state->input);
GPR_ASSERT(c <= 0xff);
*state->string_ptr++ = (gpr_uint8)c;
}
/* We are converting a UTF-32 character into UTF-8 here,
* as described by RFC3629.
*/
static void json_reader_string_add_utf32(void *userdata, gpr_uint32 c) {
if (c <= 0x7f) {
json_reader_string_add_char(userdata, c);
} else if (c <= 0x7ff) {
gpr_uint32 b1 = 0xc0 | ((c >> 6) & 0x1f);
gpr_uint32 b2 = 0x80 | (c & 0x3f);
json_reader_string_add_char(userdata, b1);
json_reader_string_add_char(userdata, b2);
} else if (c <= 0xffff) {
gpr_uint32 b1 = 0xe0 | ((c >> 12) & 0x0f);
gpr_uint32 b2 = 0x80 | ((c >> 6) & 0x3f);
gpr_uint32 b3 = 0x80 | (c & 0x3f);
json_reader_string_add_char(userdata, b1);
json_reader_string_add_char(userdata, b2);
json_reader_string_add_char(userdata, b3);
} else if (c <= 0x1fffff) {
gpr_uint32 b1 = 0xf0 | ((c >> 18) & 0x07);
gpr_uint32 b2 = 0x80 | ((c >> 12) & 0x3f);
gpr_uint32 b3 = 0x80 | ((c >> 6) & 0x3f);
gpr_uint32 b4 = 0x80 | (c & 0x3f);
json_reader_string_add_char(userdata, b1);
json_reader_string_add_char(userdata, b2);
json_reader_string_add_char(userdata, b3);
json_reader_string_add_char(userdata, b4);
}
}
/* We consider that the input may be a zero-terminated string. So we
* can end up hitting eof before the end of the alleged string length.
*/
static gpr_uint32 json_reader_read_char(void *userdata) {
gpr_uint32 r;
json_reader_userdata *state = userdata;
if (state->remaining_input == 0) return GRPC_JSON_READ_CHAR_EOF;
r = *state->input++;
state->remaining_input--;
if (r == 0) {
state->remaining_input = 0;
return GRPC_JSON_READ_CHAR_EOF;
}
return r;
}
/* Helper function to create a new grpc_json object and link it into
* our tree-in-progress inside our opaque structure.
*/
static grpc_json *json_create_and_link(void *userdata, grpc_json_type type) {
json_reader_userdata *state = userdata;
grpc_json *json = grpc_json_create(type);
json->parent = state->current_container;
json->prev = state->current_value;
state->current_value = json;
if (json->prev) {
json->prev->next = json;
}
if (json->parent) {
if (!json->parent->child) {
json->parent->child = json;
}
if (json->parent->type == GRPC_JSON_OBJECT) {
json->key = (char *)state->key;
}
}
if (!state->top) {
state->top = json;
}
return json;
}
static void json_reader_container_begins(void *userdata, grpc_json_type type) {
json_reader_userdata *state = userdata;
grpc_json *container;
GPR_ASSERT(type == GRPC_JSON_ARRAY || type == GRPC_JSON_OBJECT);
container = json_create_and_link(userdata, type);
state->current_container = container;
state->current_value = NULL;
}
/* It's important to remember that the reader is mostly stateless, so it
* isn't trying to remember what the container was prior the one that just
* ends. Since we're keeping track of these for our own purpose, we are
* able to return that information back, which is useful for it to validate
* the input json stream.
*
* Also note that if we're at the top of the tree, and the last container
* ends, we have to return GRPC_JSON_TOP_LEVEL.
*/
static grpc_json_type json_reader_container_ends(void *userdata) {
grpc_json_type container_type = GRPC_JSON_TOP_LEVEL;
json_reader_userdata *state = userdata;
GPR_ASSERT(state->current_container);
state->current_value = state->current_container;
state->current_container = state->current_container->parent;
if (state->current_container) {
container_type = state->current_container->type;
}
return container_type;
}
/* The next 3 functions basically are the reader asking us to use our string
* scratchpad for one of these 3 purposes.
*
* Note that in the set_number case, we're not going to try interpreting it.
* We'll keep it as a string, and leave it to the caller to evaluate it.
*/
static void json_reader_set_key(void *userdata) {
json_reader_userdata *state = userdata;
state->key = state->string;
}
static void json_reader_set_string(void *userdata) {
json_reader_userdata *state = userdata;
grpc_json *json = json_create_and_link(userdata, GRPC_JSON_STRING);
json->value = (char *)state->string;
}
static int json_reader_set_number(void *userdata) {
json_reader_userdata *state = userdata;
grpc_json *json = json_create_and_link(userdata, GRPC_JSON_NUMBER);
json->value = (char *)state->string;
return 1;
}
/* The object types true, false and null are self-sufficient, and don't need
* any more information beside their type.
*/
static void json_reader_set_true(void *userdata) {
json_create_and_link(userdata, GRPC_JSON_TRUE);
}
static void json_reader_set_false(void *userdata) {
json_create_and_link(userdata, GRPC_JSON_FALSE);
}
static void json_reader_set_null(void *userdata) {
json_create_and_link(userdata, GRPC_JSON_NULL);
}
static grpc_json_reader_vtable reader_vtable = {
json_reader_string_clear, json_reader_string_add_char,
json_reader_string_add_utf32, json_reader_read_char,
json_reader_container_begins, json_reader_container_ends,
json_reader_set_key, json_reader_set_string,
json_reader_set_number, json_reader_set_true,
json_reader_set_false, json_reader_set_null};
/* And finally, let's define our public API. */
grpc_json *grpc_json_parse_string_with_len(char *input, size_t size) {
grpc_json_reader reader;
json_reader_userdata state;
grpc_json *json = NULL;
grpc_json_reader_status status;
if (!input) return NULL;
state.top = state.current_container = state.current_value = NULL;
state.string = state.key = NULL;
state.string_ptr = state.input = (gpr_uint8 *)input;
state.remaining_input = size;
grpc_json_reader_init(&reader, &reader_vtable, &state);
status = grpc_json_reader_run(&reader);
json = state.top;
if ((status != GRPC_JSON_DONE) && json) {
grpc_json_destroy(json);
json = NULL;
}
return json;
}
#define UNBOUND_JSON_STRING_LENGTH 0x7fffffff
grpc_json *grpc_json_parse_string(char *input) {
return grpc_json_parse_string_with_len(input, UNBOUND_JSON_STRING_LENGTH);
}
static void json_dump_recursive(grpc_json_writer *writer, grpc_json *json,
int in_object) {
while (json) {
if (in_object) grpc_json_writer_object_key(writer, json->key);
switch (json->type) {
case GRPC_JSON_OBJECT:
case GRPC_JSON_ARRAY:
grpc_json_writer_container_begins(writer, json->type);
if (json->child)
json_dump_recursive(writer, json->child,
json->type == GRPC_JSON_OBJECT);
grpc_json_writer_container_ends(writer, json->type);
break;
case GRPC_JSON_STRING:
grpc_json_writer_value_string(writer, json->value);
break;
case GRPC_JSON_NUMBER:
grpc_json_writer_value_raw(writer, json->value);
break;
case GRPC_JSON_TRUE:
grpc_json_writer_value_raw_with_len(writer, "true", 4);
break;
case GRPC_JSON_FALSE:
grpc_json_writer_value_raw_with_len(writer, "false", 5);
break;
case GRPC_JSON_NULL:
grpc_json_writer_value_raw_with_len(writer, "null", 4);
break;
default:
GPR_UNREACHABLE_CODE(abort());
}
json = json->next;
}
}
static grpc_json_writer_vtable writer_vtable = {
json_writer_output_char, json_writer_output_string,
json_writer_output_string_with_len};
char *grpc_json_dump_to_string(grpc_json *json, int indent) {
grpc_json_writer writer;
json_writer_userdata state;
state.output = NULL;
state.free_space = state.string_len = state.allocated = 0;
grpc_json_writer_init(&writer, indent, &writer_vtable, &state);
json_dump_recursive(&writer, json, 0);
json_writer_output_char(&state, 0);
return state.output;
}
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