grpc/test/core/json/json_rewrite.cc

/*
 *
 * Copyright 2015 gRPC authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

#include <stdio.h>
#include <stdlib.h>

#include <grpc/support/alloc.h>
#include <grpc/support/cmdline.h>
#include <grpc/support/log.h>

#include "src/core/lib/json/json_reader.h"
#include "src/core/lib/json/json_writer.h"

typedef struct json_writer_userdata {
  FILE* out;
} json_writer_userdata;

typedef struct stacked_container {
  grpc_json_type type;
  struct stacked_container* next;
} stacked_container;

typedef struct json_reader_userdata {
  FILE* in;
  grpc_json_writer* writer;
  char* scratchpad;
  char* ptr;
  size_t free_space;
  size_t allocated;
  size_t string_len;
  stacked_container* top;
} json_reader_userdata;

static void json_writer_output_char(void* userdata, char c) {
  json_writer_userdata* state = static_cast<json_writer_userdata*>(userdata);
  fputc(c, state->out);
}

static void json_writer_output_string(void* userdata, const char* str) {
  json_writer_userdata* state = static_cast<json_writer_userdata*>(userdata);
  fputs(str, state->out);
}

static void json_writer_output_string_with_len(void* userdata, const char* str,
                                               size_t len) {
  json_writer_userdata* state = static_cast<json_writer_userdata*>(userdata);
  fwrite(str, len, 1, state->out);
}

grpc_json_writer_vtable writer_vtable = {json_writer_output_char,
                                         json_writer_output_string,
                                         json_writer_output_string_with_len};

static void check_string(json_reader_userdata* state, size_t needed) {
  if (state->free_space >= needed) return;
  needed -= state->free_space;
  needed = (needed + 0xffu) & ~0xffu;
  state->scratchpad = static_cast<char*>(
      gpr_realloc(state->scratchpad, state->allocated + needed));
  state->free_space += needed;
  state->allocated += needed;
}

static void json_reader_string_clear(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);
  state->free_space = state->allocated;
  state->string_len = 0;
}

static void json_reader_string_add_char(void* userdata, uint32_t c) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);
  check_string(state, 1);
  GPR_ASSERT(c < 256);
  state->scratchpad[state->string_len++] = (char)c;
}

static void json_reader_string_add_utf32(void* userdata, uint32_t c) {
  if (c <= 0x7f) {
    json_reader_string_add_char(userdata, c);
  } else if (c <= 0x7ff) {
    uint32_t b1 = 0xc0u | ((c >> 6u) & 0x1fu);
    uint32_t b2 = 0x80u | (c & 0x3fu);
    json_reader_string_add_char(userdata, b1);
    json_reader_string_add_char(userdata, b2);
  } else if (c <= 0xffffu) {
    uint32_t b1 = 0xe0u | ((c >> 12u) & 0x0fu);
    uint32_t b2 = 0x80u | ((c >> 6u) & 0x3fu);
    uint32_t b3 = 0x80u | (c & 0x3fu);
    json_reader_string_add_char(userdata, b1);
    json_reader_string_add_char(userdata, b2);
    json_reader_string_add_char(userdata, b3);
  } else if (c <= 0x1fffffu) {
    uint32_t b1 = 0xf0u | ((c >> 18u) & 0x07u);
    uint32_t b2 = 0x80u | ((c >> 12u) & 0x3fu);
    uint32_t b3 = 0x80u | ((c >> 6u) & 0x3fu);
    uint32_t b4 = 0x80u | (c & 0x3fu);
    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);
  }
}

static uint32_t json_reader_read_char(void* userdata) {
  int r;
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);

  r = fgetc(state->in);
  if (r == EOF) r = GRPC_JSON_READ_CHAR_EOF;
  return (uint32_t)r;
}

static void json_reader_container_begins(void* userdata, grpc_json_type type) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);
  stacked_container* container =
      static_cast<stacked_container*>(gpr_malloc(sizeof(stacked_container)));

  container->type = type;
  container->next = state->top;
  state->top = container;

  grpc_json_writer_container_begins(state->writer, type);
}

static grpc_json_type json_reader_container_ends(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);
  stacked_container* container = state->top;

  grpc_json_writer_container_ends(state->writer, container->type);
  state->top = container->next;
  gpr_free(container);
  return state->top ? state->top->type : GRPC_JSON_TOP_LEVEL;
}

static void json_reader_set_key(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);
  json_reader_string_add_char(userdata, 0);

  grpc_json_writer_object_key(state->writer, state->scratchpad);
}

static void json_reader_set_string(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);
  json_reader_string_add_char(userdata, 0);

  grpc_json_writer_value_string(state->writer, state->scratchpad);
}

static int json_reader_set_number(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);

  grpc_json_writer_value_raw_with_len(state->writer, state->scratchpad,
                                      state->string_len);

  return 1;
}

static void json_reader_set_true(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);

  grpc_json_writer_value_raw_with_len(state->writer, "true", 4);
}

static void json_reader_set_false(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);

  grpc_json_writer_value_raw_with_len(state->writer, "false", 5);
}

static void json_reader_set_null(void* userdata) {
  json_reader_userdata* state = static_cast<json_reader_userdata*>(userdata);

  grpc_json_writer_value_raw_with_len(state->writer, "null", 4);
}

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};

int rewrite(FILE* in, FILE* out, int indent) {
  grpc_json_writer writer;
  grpc_json_reader reader;
  grpc_json_reader_status status;
  json_writer_userdata writer_user;
  json_reader_userdata reader_user;

  reader_user.writer = &writer;
  reader_user.in = in;
  reader_user.top = nullptr;
  reader_user.scratchpad = nullptr;
  reader_user.string_len = 0;
  reader_user.free_space = 0;
  reader_user.allocated = 0;

  writer_user.out = out;

  grpc_json_writer_init(&writer, indent, &writer_vtable, &writer_user);
  grpc_json_reader_init(&reader, &reader_vtable, &reader_user);

  status = grpc_json_reader_run(&reader);

  free(reader_user.scratchpad);
  while (reader_user.top) {
    stacked_container* container = reader_user.top;
    reader_user.top = container->next;
    free(container);
  }

  return status == GRPC_JSON_DONE;
}

int main(int argc, char** argv) {
  int indent = 2;
  gpr_cmdline* cl;

  cl = gpr_cmdline_create(nullptr);
  gpr_cmdline_add_int(cl, "indent", nullptr, &indent);
  gpr_cmdline_parse(cl, argc, argv);
  gpr_cmdline_destroy(cl);

  return rewrite(stdin, stdout, indent) ? 0 : 1;
}