base/files/file_util.cc

   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/files/file_util.h"
   6
   7 #if defined(OS_WIN)
   8 #include <io.h>
   9 #endif
  10 #include <stdio.h>
  11
  12 #include <fstream>
  13 #include <limits>
  14
  15 #include "base/files/file_enumerator.h"
  16 #include "base/files/file_path.h"
  17 #include "base/logging.h"
  18 #include "base/strings/string_piece.h"
  19 #include "base/strings/string_util.h"
  20 #include "base/strings/stringprintf.h"
  21 #include "base/strings/utf_string_conversions.h"
  22
  23 namespace base {
  24
  25 namespace {
  26
  27 // The maximum number of 'uniquified' files we will try to create.
  28 // This is used when the filename we're trying to download is already in use,
  29 // so we create a new unique filename by appending " (nnn)" before the
  30 // extension, where 1 <= nnn <= kMaxUniqueFiles.
  31 // Also used by code that cleans up said files.
  32 static const int kMaxUniqueFiles = 100;
  33
  34 }  // namespace
  35
  36 int64 ComputeDirectorySize(const FilePath& root_path) {
  37   int64 running_size = 0;
  38   FileEnumerator file_iter(root_path, true, FileEnumerator::FILES);
  39   while (!file_iter.Next().empty())
  40     running_size += file_iter.GetInfo().GetSize();
  41   return running_size;
  42 }
  43
  44 bool Move(const FilePath& from_path, const FilePath& to_path) {
  45   if (from_path.ReferencesParent() || to_path.ReferencesParent())
  46     return false;
  47   return internal::MoveUnsafe(from_path, to_path);
  48 }
  49
  50 bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
  51   if (from_path.ReferencesParent() || to_path.ReferencesParent())
  52     return false;
  53   return internal::CopyFileUnsafe(from_path, to_path);
  54 }
  55
  56 bool ContentsEqual(const FilePath& filename1, const FilePath& filename2) {
  57   // We open the file in binary format even if they are text files because
  58   // we are just comparing that bytes are exactly same in both files and not
  59   // doing anything smart with text formatting.
  60   std::ifstream file1(filename1.value().c_str(),
  61                       std::ios::in | std::ios::binary);
  62   std::ifstream file2(filename2.value().c_str(),
  63                       std::ios::in | std::ios::binary);
  64
  65   // Even if both files aren't openable (and thus, in some sense, "equal"),
  66   // any unusable file yields a result of "false".
  67   if (!file1.is_open() || !file2.is_open())
  68     return false;
  69
  70   const int BUFFER_SIZE = 2056;
  71   char buffer1[BUFFER_SIZE], buffer2[BUFFER_SIZE];
  72   do {
  73     file1.read(buffer1, BUFFER_SIZE);
  74     file2.read(buffer2, BUFFER_SIZE);
  75
  76     if ((file1.eof() != file2.eof()) ||
  77         (file1.gcount() != file2.gcount()) ||
  78         (memcmp(buffer1, buffer2, file1.gcount()))) {
  79       file1.close();
  80       file2.close();
  81       return false;
  82     }
  83   } while (!file1.eof() || !file2.eof());
  84
  85   file1.close();
  86   file2.close();
  87   return true;
  88 }
  89
  90 bool TextContentsEqual(const FilePath& filename1, const FilePath& filename2) {
  91   std::ifstream file1(filename1.value().c_str(), std::ios::in);
  92   std::ifstream file2(filename2.value().c_str(), std::ios::in);
  93
  94   // Even if both files aren't openable (and thus, in some sense, "equal"),
  95   // any unusable file yields a result of "false".
  96   if (!file1.is_open() || !file2.is_open())
  97     return false;
  98
  99   do {
 100     std::string line1, line2;
 101     getline(file1, line1);
 102     getline(file2, line2);
 103
 104     // Check for mismatched EOF states, or any error state.
 105     if ((file1.eof() != file2.eof()) ||
 106         file1.bad() || file2.bad()) {
 107       return false;
 108     }
 109
 110     // Trim all '\r' and '\n' characters from the end of the line.
 111     std::string::size_type end1 = line1.find_last_not_of("\r\n");
 112     if (end1 == std::string::npos)
 113       line1.clear();
 114     else if (end1 + 1 < line1.length())
 115       line1.erase(end1 + 1);
 116
 117     std::string::size_type end2 = line2.find_last_not_of("\r\n");
 118     if (end2 == std::string::npos)
 119       line2.clear();
 120     else if (end2 + 1 < line2.length())
 121       line2.erase(end2 + 1);
 122
 123     if (line1 != line2)
 124       return false;
 125   } while (!file1.eof() || !file2.eof());
 126
 127   return true;
 128 }
 129
 130 bool ReadFileToString(const FilePath& path,
 131                       std::string* contents,
 132                       size_t max_size) {
 133   if (contents)
 134     contents->clear();
 135   if (path.ReferencesParent())
 136     return false;
 137   FILE* file = OpenFile(path, "rb");
 138   if (!file) {
 139     return false;
 140   }
 141
 142   char buf[1 << 16];
 143   size_t len;
 144   size_t size = 0;
 145   bool read_status = true;
 146
 147   // Many files supplied in |path| have incorrect size (proc files etc).
 148   // Hence, the file is read sequentially as opposed to a one-shot read.
 149   while ((len = fread(buf, 1, sizeof(buf), file)) > 0) {
 150     if (contents)
 151       contents->append(buf, std::min(len, max_size - size));
 152
 153     if ((max_size - size) < len) {
 154       read_status = false;
 155       break;
 156     }
 157
 158     size += len;
 159   }
 160   read_status = read_status && !ferror(file);
 161   CloseFile(file);
 162
 163   return read_status;
 164 }
 165
 166 bool ReadFileToString(const FilePath& path, std::string* contents) {
 167   return ReadFileToString(path, contents, std::numeric_limits<size_t>::max());
 168 }
 169
 170 bool IsDirectoryEmpty(const FilePath& dir_path) {
 171   FileEnumerator files(dir_path, false,
 172       FileEnumerator::FILES | FileEnumerator::DIRECTORIES);
 173   if (files.Next().empty())
 174     return true;
 175   return false;
 176 }
 177
 178 FILE* CreateAndOpenTemporaryFile(FilePath* path) {
 179   FilePath directory;
 180   if (!GetTempDir(&directory))
 181     return NULL;
 182
 183   return CreateAndOpenTemporaryFileInDir(directory, path);
 184 }
 185
 186 bool CreateDirectory(const FilePath& full_path) {
 187   return CreateDirectoryAndGetError(full_path, NULL);
 188 }
 189
 190 bool GetFileSize(const FilePath& file_path, int64* file_size) {
 191   File::Info info;
 192   if (!GetFileInfo(file_path, &info))
 193     return false;
 194   *file_size = info.size;
 195   return true;
 196 }
 197
 198 bool TouchFile(const FilePath& path,
 199                const Time& last_accessed,
 200                const Time& last_modified) {
 201   int flags = File::FLAG_OPEN | File::FLAG_WRITE_ATTRIBUTES;
 202
 203 #if defined(OS_WIN)
 204   // On Windows, FILE_FLAG_BACKUP_SEMANTICS is needed to open a directory.
 205   if (DirectoryExists(path))
 206     flags |= File::FLAG_BACKUP_SEMANTICS;
 207 #endif  // OS_WIN
 208
 209   File file(path, flags);
 210   if (!file.IsValid())
 211     return false;
 212
 213   return file.SetTimes(last_accessed, last_modified);
 214 }
 215
 216 bool CloseFile(FILE* file) {
 217   if (file == NULL)
 218     return true;
 219   return fclose(file) == 0;
 220 }
 221
 222 bool TruncateFile(FILE* file) {
 223   if (file == NULL)
 224     return false;
 225   long current_offset = ftell(file);
 226   if (current_offset == -1)
 227     return false;
 228 #if defined(OS_WIN)
 229   int fd = _fileno(file);
 230   if (_chsize(fd, current_offset) != 0)
 231     return false;
 232 #else
 233   int fd = fileno(file);
 234   if (ftruncate(fd, current_offset) != 0)
 235     return false;
 236 #endif
 237   return true;
 238 }
 239
 240 int GetUniquePathNumber(const FilePath& path,
 241                         const FilePath::StringType& suffix) {
 242   bool have_suffix = !suffix.empty();
 243   if (!PathExists(path) &&
 244       (!have_suffix || !PathExists(FilePath(path.value() + suffix)))) {
 245     return 0;
 246   }
 247
 248   FilePath new_path;
 249   for (int count = 1; count <= kMaxUniqueFiles; ++count) {
 250     new_path = path.InsertBeforeExtensionASCII(StringPrintf(" (%d)", count));
 251     if (!PathExists(new_path) &&
 252         (!have_suffix || !PathExists(FilePath(new_path.value() + suffix)))) {
 253       return count;
 254     }
 255   }
 256
 257   return -1;
 258 }
 259
 260 }  // namespace base