Move json_value_serializer from content/common to base.

R=darin@chromium.org
BUG=92044
TEST=

Review URL: http://codereview.chromium.org/8165009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@104527 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 237 insertions, 0 deletions

diff --git a/base/json/json_value_serializer.cc b/base/json/json_value_serializer.cc
new file mode 100644
index 0000000..d667bc1
--- /dev/null
+++ b/base/json/json_value_serializer.cc
@@ -0,0 +1,108 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/json/json_value_serializer.h"
+
+#include "base/file_util.h"
+#include "base/json/json_reader.h"
+#include "base/json/json_writer.h"
+#include "base/string_util.h"
+
+const char* JSONFileValueSerializer::kAccessDenied = "Access denied.";
+const char* JSONFileValueSerializer::kCannotReadFile = "Can't read file.";
+const char* JSONFileValueSerializer::kFileLocked = "File locked.";
+const char* JSONFileValueSerializer::kNoSuchFile = "File doesn't exist.";
+
+JSONStringValueSerializer::~JSONStringValueSerializer() {}
+
+bool JSONStringValueSerializer::Serialize(const Value& root) {
+  if (!json_string_ || initialized_with_const_string_)
+    return false;
+
+  base::JSONWriter::Write(&root, pretty_print_, json_string_);
+  return true;
+}
+
+Value* JSONStringValueSerializer::Deserialize(int* error_code,
+                                              std::string* error_str) {
+  if (!json_string_)
+    return NULL;
+
+  return base::JSONReader::ReadAndReturnError(*json_string_,
+                                              allow_trailing_comma_,
+                                              error_code,
+                                              error_str);
+}
+
+/******* File Serializer *******/
+
+bool JSONFileValueSerializer::Serialize(const Value& root) {
+  std::string json_string;
+  JSONStringValueSerializer serializer(&json_string);
+  serializer.set_pretty_print(true);
+  bool result = serializer.Serialize(root);
+  if (!result)
+    return false;
+
+  int data_size = static_cast<int>(json_string.size());
+  if (file_util::WriteFile(json_file_path_,
+                           json_string.data(),
+                           data_size) != data_size)
+    return false;
+
+  return true;
+}
+
+int JSONFileValueSerializer::ReadFileToString(std::string* json_string) {
+  DCHECK(json_string);
+  if (!file_util::ReadFileToString(json_file_path_, json_string)) {
+#if defined(OS_WIN)
+    int error = ::GetLastError();
+    if (error == ERROR_SHARING_VIOLATION || error == ERROR_LOCK_VIOLATION) {
+      return JSON_FILE_LOCKED;
+    } else if (error == ERROR_ACCESS_DENIED) {
+      return JSON_ACCESS_DENIED;
+    }
+#endif
+    if (!file_util::PathExists(json_file_path_))
+      return JSON_NO_SUCH_FILE;
+    else
+      return JSON_CANNOT_READ_FILE;
+  }
+  return JSON_NO_ERROR;
+}
+
+const char* JSONFileValueSerializer::GetErrorMessageForCode(int error_code) {
+  switch (error_code) {
+    case JSON_NO_ERROR:
+      return "";
+    case JSON_ACCESS_DENIED:
+      return kAccessDenied;
+    case JSON_CANNOT_READ_FILE:
+      return kCannotReadFile;
+    case JSON_FILE_LOCKED:
+      return kFileLocked;
+    case JSON_NO_SUCH_FILE:
+      return kNoSuchFile;
+    default:
+      NOTREACHED();
+      return "";
+  }
+}
+
+Value* JSONFileValueSerializer::Deserialize(int* error_code,
+                                            std::string* error_str) {
+  std::string json_string;
+  int error = ReadFileToString(&json_string);
+  if (error != JSON_NO_ERROR) {
+    if (error_code)
+      *error_code = error;
+    if (error_str)
+      *error_str = GetErrorMessageForCode(error);
+    return NULL;
+  }
+
+  JSONStringValueSerializer serializer(json_string);
+  return serializer.Deserialize(error_code, error_str);
+}
diff --git a/base/json/json_value_serializer.h b/base/json/json_value_serializer.h
new file mode 100644
index 0000000..650008e
--- /dev/null
+++ b/base/json/json_value_serializer.h
@@ -0,0 +1,129 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_JSON_JSON_VALUE_SERIALIZER_H_
+#define BASE_JSON_JSON_VALUE_SERIALIZER_H_
+#pragma once
+
+#include <string>
+
+#include "base/base_export.h"
+#include "base/basictypes.h"
+#include "base/file_path.h"
+#include "base/values.h"
+
+class BASE_EXPORT JSONStringValueSerializer : public base::ValueSerializer {
+ public:
+  // json_string is the string that will be source of the deserialization
+  // or the destination of the serialization.  The caller of the constructor
+  // retains ownership of the string.
+  explicit JSONStringValueSerializer(std::string* json_string)
+      : json_string_(json_string),
+        initialized_with_const_string_(false),
+        pretty_print_(false),
+        allow_trailing_comma_(false) {
+  }
+
+  // This version allows initialization with a const string reference for
+  // deserialization only.
+  explicit JSONStringValueSerializer(const std::string& json_string)
+      : json_string_(&const_cast<std::string&>(json_string)),
+        initialized_with_const_string_(true),
+        pretty_print_(false),
+        allow_trailing_comma_(false) {
+  }
+
+  virtual ~JSONStringValueSerializer();
+
+  // Attempt to serialize the data structure represented by Value into
+  // JSON.  If the return value is true, the result will have been written
+  // into the string passed into the constructor.
+  virtual bool Serialize(const Value& root);
+
+  // Attempt to deserialize the data structure encoded in the string passed
+  // in to the constructor into a structure of Value objects.  If the return
+  // value is NULL, and if |error_code| is non-null, |error_code| will
+  // contain an integer error code (either JsonFileError or JsonParseError).
+  // If |error_message| is non-null, it will be filled in with a formatted
+  // error message including the location of the error if appropriate.
+  // The caller takes ownership of the returned value.
+  virtual Value* Deserialize(int* error_code, std::string* error_message);
+
+  void set_pretty_print(bool new_value) { pretty_print_ = new_value; }
+  bool pretty_print() { return pretty_print_; }
+
+  void set_allow_trailing_comma(bool new_value) {
+    allow_trailing_comma_ = new_value;
+  }
+
+ private:
+  std::string* json_string_;
+  bool initialized_with_const_string_;
+  bool pretty_print_;  // If true, serialization will span multiple lines.
+  // If true, deserialization will allow trailing commas.
+  bool allow_trailing_comma_;
+
+  DISALLOW_COPY_AND_ASSIGN(JSONStringValueSerializer);
+};
+
+class BASE_EXPORT JSONFileValueSerializer : public base::ValueSerializer {
+ public:
+  // json_file_patch is the path of a file that will be source of the
+  // deserialization or the destination of the serialization.
+  // When deserializing, the file should exist, but when serializing, the
+  // serializer will attempt to create the file at the specified location.
+  explicit JSONFileValueSerializer(const FilePath& json_file_path)
+    : json_file_path_(json_file_path) {}
+
+  virtual ~JSONFileValueSerializer() {}
+
+  // DO NOT USE except in unit tests to verify the file was written properly.
+  // We should never serialize directly to a file since this will block the
+  // thread. Instead, serialize to a string and write to the file you want on
+  // the file thread.
+  //
+  // Attempt to serialize the data structure represented by Value into
+  // JSON.  If the return value is true, the result will have been written
+  // into the file whose name was passed into the constructor.
+  virtual bool Serialize(const Value& root);
+
+  // Attempt to deserialize the data structure encoded in the file passed
+  // in to the constructor into a structure of Value objects.  If the return
+  // value is NULL, and if |error_code| is non-null, |error_code| will
+  // contain an integer error code (either JsonFileError or JsonParseError).
+  // If |error_message| is non-null, it will be filled in with a formatted
+  // error message including the location of the error if appropriate.
+  // The caller takes ownership of the returned value.
+  virtual Value* Deserialize(int* error_code, std::string* error_message);
+
+  // This enum is designed to safely overlap with JSONReader::JsonParseError.
+  enum JsonFileError {
+    JSON_NO_ERROR = 0,
+    JSON_ACCESS_DENIED = 1000,
+    JSON_CANNOT_READ_FILE,
+    JSON_FILE_LOCKED,
+    JSON_NO_SUCH_FILE
+  };
+
+  // File-specific error messages that can be returned.
+  static const char* kAccessDenied;
+  static const char* kCannotReadFile;
+  static const char* kFileLocked;
+  static const char* kNoSuchFile;
+
+  // Convert an error code into an error message.  |error_code| is assumed to
+  // be a JsonFileError.
+  static const char* GetErrorMessageForCode(int error_code);
+
+ private:
+  FilePath json_file_path_;
+
+  // A wrapper for file_util::ReadFileToString which returns a non-zero
+  // JsonFileError if there were file errors.
+  int ReadFileToString(std::string* json_string);
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(JSONFileValueSerializer);
+};
+
+#endif  // BASE_JSON_JSON_VALUE_SERIALIZER_H_