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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/json/json_file_value_serializer.h"
      6 
      7 #include "base/files/file_util.h"
      8 #include "base/json/json_string_value_serializer.h"
      9 #include "base/logging.h"
     10 #include "build/build_config.h"
     11 
     12 using base::FilePath;
     13 
     14 const char JSONFileValueDeserializer::kAccessDenied[] = "Access denied.";
     15 const char JSONFileValueDeserializer::kCannotReadFile[] = "Can't read file.";
     16 const char JSONFileValueDeserializer::kFileLocked[] = "File locked.";
     17 const char JSONFileValueDeserializer::kNoSuchFile[] = "File doesn't exist.";
     18 
     19 JSONFileValueSerializer::JSONFileValueSerializer(
     20     const base::FilePath& json_file_path)
     21     : json_file_path_(json_file_path) {
     22 }
     23 
     24 JSONFileValueSerializer::~JSONFileValueSerializer() {
     25 }
     26 
     27 bool JSONFileValueSerializer::Serialize(const base::Value& root) {
     28   return SerializeInternal(root, false);
     29 }
     30 
     31 bool JSONFileValueSerializer::SerializeAndOmitBinaryValues(
     32     const base::Value& root) {
     33   return SerializeInternal(root, true);
     34 }
     35 
     36 bool JSONFileValueSerializer::SerializeInternal(const base::Value& root,
     37                                                 bool omit_binary_values) {
     38   std::string json_string;
     39   JSONStringValueSerializer serializer(&json_string);
     40   serializer.set_pretty_print(true);
     41   bool result = omit_binary_values ?
     42       serializer.SerializeAndOmitBinaryValues(root) :
     43       serializer.Serialize(root);
     44   if (!result)
     45     return false;
     46 
     47   int data_size = static_cast<int>(json_string.size());
     48   if (base::WriteFile(json_file_path_, json_string.data(), data_size) !=
     49       data_size)
     50     return false;
     51 
     52   return true;
     53 }
     54 
     55 JSONFileValueDeserializer::JSONFileValueDeserializer(
     56     const base::FilePath& json_file_path)
     57     : json_file_path_(json_file_path),
     58       allow_trailing_comma_(false),
     59       last_read_size_(0U) {
     60 }
     61 
     62 JSONFileValueDeserializer::~JSONFileValueDeserializer() {
     63 }
     64 
     65 int JSONFileValueDeserializer::ReadFileToString(std::string* json_string) {
     66   DCHECK(json_string);
     67   if (!base::ReadFileToString(json_file_path_, json_string)) {
     68 #if defined(OS_WIN)
     69     int error = ::GetLastError();
     70     if (error == ERROR_SHARING_VIOLATION || error == ERROR_LOCK_VIOLATION) {
     71       return JSON_FILE_LOCKED;
     72     } else if (error == ERROR_ACCESS_DENIED) {
     73       return JSON_ACCESS_DENIED;
     74     }
     75 #endif
     76     if (!base::PathExists(json_file_path_))
     77       return JSON_NO_SUCH_FILE;
     78     else
     79       return JSON_CANNOT_READ_FILE;
     80   }
     81 
     82   last_read_size_ = json_string->size();
     83   return JSON_NO_ERROR;
     84 }
     85 
     86 const char* JSONFileValueDeserializer::GetErrorMessageForCode(int error_code) {
     87   switch (error_code) {
     88     case JSON_NO_ERROR:
     89       return "";
     90     case JSON_ACCESS_DENIED:
     91       return kAccessDenied;
     92     case JSON_CANNOT_READ_FILE:
     93       return kCannotReadFile;
     94     case JSON_FILE_LOCKED:
     95       return kFileLocked;
     96     case JSON_NO_SUCH_FILE:
     97       return kNoSuchFile;
     98     default:
     99       NOTREACHED();
    100       return "";
    101   }
    102 }
    103 
    104 std::unique_ptr<base::Value> JSONFileValueDeserializer::Deserialize(
    105     int* error_code,
    106     std::string* error_str) {
    107   std::string json_string;
    108   int error = ReadFileToString(&json_string);
    109   if (error != JSON_NO_ERROR) {
    110     if (error_code)
    111       *error_code = error;
    112     if (error_str)
    113       *error_str = GetErrorMessageForCode(error);
    114     return NULL;
    115   }
    116 
    117   JSONStringValueDeserializer deserializer(json_string);
    118   deserializer.set_allow_trailing_comma(allow_trailing_comma_);
    119   return deserializer.Deserialize(error_code, error_str);
    120 }
    121