Initial checkin of gRPC to third_party/

third_party/grpc/src/core/json/json_string.c

+/*
+ *
+ * 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;
+  uint8_t *input;
+  uint8_t *key;
+  uint8_t *string;
+  uint8_t *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, uint32_t c) {
+  json_reader_userdata *state = userdata;
+  GPR_ASSERT(state->string_ptr < state->input);
+  GPR_ASSERT(c <= 0xff);
+  *state->string_ptr++ = (uint8_t)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, uint32_t c) {
+  if (c <= 0x7f) {
+    json_reader_string_add_char(userdata, c);
+  } else if (c <= 0x7ff) {
+    uint32_t b1 = 0xc0 | ((c >> 6) & 0x1f);
+    uint32_t b2 = 0x80 | (c & 0x3f);
+    json_reader_string_add_char(userdata, b1);
+    json_reader_string_add_char(userdata, b2);
+  } else if (c <= 0xffff) {
+    uint32_t b1 = 0xe0 | ((c >> 12) & 0x0f);
+    uint32_t b2 = 0x80 | ((c >> 6) & 0x3f);
+    uint32_t 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) {
+    uint32_t b1 = 0xf0 | ((c >> 18) & 0x07);
+    uint32_t b2 = 0x80 | ((c >> 12) & 0x3f);
+    uint32_t b3 = 0x80 | ((c >> 6) & 0x3f);
+    uint32_t 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 uint32_t json_reader_read_char(void *userdata) {
+  uint32_t 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 = (uint8_t *)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;
+}