Updating trunk VERSION from 2139.0 to 2140.0
[chromium-blink-merge.git] / base / files / file_util.h
blobfeebeed919697e3ec12c231f63a60868eb1b0a7a
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.
5 // This file contains utility functions for dealing with the local
6 // filesystem.
8 #ifndef BASE_FILES_FILE_UTIL_H_
9 #define BASE_FILES_FILE_UTIL_H_
11 #include "build/build_config.h"
13 #if defined(OS_WIN)
14 #include <windows.h>
15 #elif defined(OS_POSIX)
16 #include <sys/stat.h>
17 #include <unistd.h>
18 #endif
20 #include <stdio.h>
22 #include <set>
23 #include <string>
24 #include <vector>
26 #include "base/base_export.h"
27 #include "base/basictypes.h"
28 #include "base/files/file.h"
29 #include "base/files/file_path.h"
30 #include "base/memory/scoped_ptr.h"
31 #include "base/strings/string16.h"
33 #if defined(OS_POSIX)
34 #include "base/file_descriptor_posix.h"
35 #include "base/logging.h"
36 #include "base/posix/eintr_wrapper.h"
37 #endif
39 namespace base {
41 class Time;
43 //-----------------------------------------------------------------------------
44 // Functions that involve filesystem access or modification:
46 // Returns an absolute version of a relative path. Returns an empty path on
47 // error. On POSIX, this function fails if the path does not exist. This
48 // function can result in I/O so it can be slow.
49 BASE_EXPORT FilePath MakeAbsoluteFilePath(const FilePath& input);
51 // Returns the total number of bytes used by all the files under |root_path|.
52 // If the path does not exist the function returns 0.
54 // This function is implemented using the FileEnumerator class so it is not
55 // particularly speedy in any platform.
56 BASE_EXPORT int64 ComputeDirectorySize(const FilePath& root_path);
58 // Deletes the given path, whether it's a file or a directory.
59 // If it's a directory, it's perfectly happy to delete all of the
60 // directory's contents. Passing true to recursive deletes
61 // subdirectories and their contents as well.
62 // Returns true if successful, false otherwise. It is considered successful
63 // to attempt to delete a file that does not exist.
65 // In posix environment and if |path| is a symbolic link, this deletes only
66 // the symlink. (even if the symlink points to a non-existent file)
68 // WARNING: USING THIS WITH recursive==true IS EQUIVALENT
69 // TO "rm -rf", SO USE WITH CAUTION.
70 BASE_EXPORT bool DeleteFile(const FilePath& path, bool recursive);
72 #if defined(OS_WIN)
73 // Schedules to delete the given path, whether it's a file or a directory, until
74 // the operating system is restarted.
75 // Note:
76 // 1) The file/directory to be deleted should exist in a temp folder.
77 // 2) The directory to be deleted must be empty.
78 BASE_EXPORT bool DeleteFileAfterReboot(const FilePath& path);
79 #endif
81 // Moves the given path, whether it's a file or a directory.
82 // If a simple rename is not possible, such as in the case where the paths are
83 // on different volumes, this will attempt to copy and delete. Returns
84 // true for success.
85 // This function fails if either path contains traversal components ('..').
86 BASE_EXPORT bool Move(const FilePath& from_path, const FilePath& to_path);
88 // Renames file |from_path| to |to_path|. Both paths must be on the same
89 // volume, or the function will fail. Destination file will be created
90 // if it doesn't exist. Prefer this function over Move when dealing with
91 // temporary files. On Windows it preserves attributes of the target file.
92 // Returns true on success, leaving *error unchanged.
93 // Returns false on failure and sets *error appropriately, if it is non-NULL.
94 BASE_EXPORT bool ReplaceFile(const FilePath& from_path,
95 const FilePath& to_path,
96 File::Error* error);
98 // Copies a single file. Use CopyDirectory to copy directories.
99 // This function fails if either path contains traversal components ('..').
101 // This function keeps the metadata on Windows. The read only bit on Windows is
102 // not kept.
103 BASE_EXPORT bool CopyFile(const FilePath& from_path, const FilePath& to_path);
105 // Copies the given path, and optionally all subdirectories and their contents
106 // as well.
108 // If there are files existing under to_path, always overwrite. Returns true
109 // if successful, false otherwise. Wildcards on the names are not supported.
111 // This function calls into CopyFile() so the same behavior w.r.t. metadata
112 // applies.
114 // If you only need to copy a file use CopyFile, it's faster.
115 BASE_EXPORT bool CopyDirectory(const FilePath& from_path,
116 const FilePath& to_path,
117 bool recursive);
119 // Returns true if the given path exists on the local filesystem,
120 // false otherwise.
121 BASE_EXPORT bool PathExists(const FilePath& path);
123 // Returns true if the given path is writable by the user, false otherwise.
124 BASE_EXPORT bool PathIsWritable(const FilePath& path);
126 // Returns true if the given path exists and is a directory, false otherwise.
127 BASE_EXPORT bool DirectoryExists(const FilePath& path);
129 // Returns true if the contents of the two files given are equal, false
130 // otherwise. If either file can't be read, returns false.
131 BASE_EXPORT bool ContentsEqual(const FilePath& filename1,
132 const FilePath& filename2);
134 // Returns true if the contents of the two text files given are equal, false
135 // otherwise. This routine treats "\r\n" and "\n" as equivalent.
136 BASE_EXPORT bool TextContentsEqual(const FilePath& filename1,
137 const FilePath& filename2);
139 // Reads the file at |path| into |contents| and returns true on success and
140 // false on error. For security reasons, a |path| containing path traversal
141 // components ('..') is treated as a read error and |contents| is set to empty.
142 // In case of I/O error, |contents| holds the data that could be read from the
143 // file before the error occurred.
144 // |contents| may be NULL, in which case this function is useful for its side
145 // effect of priming the disk cache (could be used for unit tests).
146 BASE_EXPORT bool ReadFileToString(const FilePath& path, std::string* contents);
148 // Reads the file at |path| into |contents| and returns true on success and
149 // false on error. For security reasons, a |path| containing path traversal
150 // components ('..') is treated as a read error and |contents| is set to empty.
151 // In case of I/O error, |contents| holds the data that could be read from the
152 // file before the error occurred. When the file size exceeds |max_size|, the
153 // function returns false with |contents| holding the file truncated to
154 // |max_size|.
155 // |contents| may be NULL, in which case this function is useful for its side
156 // effect of priming the disk cache (could be used for unit tests).
157 BASE_EXPORT bool ReadFileToString(const FilePath& path,
158 std::string* contents,
159 size_t max_size);
161 #if defined(OS_POSIX)
163 // Read exactly |bytes| bytes from file descriptor |fd|, storing the result
164 // in |buffer|. This function is protected against EINTR and partial reads.
165 // Returns true iff |bytes| bytes have been successfully read from |fd|.
166 BASE_EXPORT bool ReadFromFD(int fd, char* buffer, size_t bytes);
168 // Creates a symbolic link at |symlink| pointing to |target|. Returns
169 // false on failure.
170 BASE_EXPORT bool CreateSymbolicLink(const FilePath& target,
171 const FilePath& symlink);
173 // Reads the given |symlink| and returns where it points to in |target|.
174 // Returns false upon failure.
175 BASE_EXPORT bool ReadSymbolicLink(const FilePath& symlink, FilePath* target);
177 // Bits and masks of the file permission.
178 enum FilePermissionBits {
179 FILE_PERMISSION_MASK = S_IRWXU | S_IRWXG | S_IRWXO,
180 FILE_PERMISSION_USER_MASK = S_IRWXU,
181 FILE_PERMISSION_GROUP_MASK = S_IRWXG,
182 FILE_PERMISSION_OTHERS_MASK = S_IRWXO,
184 FILE_PERMISSION_READ_BY_USER = S_IRUSR,
185 FILE_PERMISSION_WRITE_BY_USER = S_IWUSR,
186 FILE_PERMISSION_EXECUTE_BY_USER = S_IXUSR,
187 FILE_PERMISSION_READ_BY_GROUP = S_IRGRP,
188 FILE_PERMISSION_WRITE_BY_GROUP = S_IWGRP,
189 FILE_PERMISSION_EXECUTE_BY_GROUP = S_IXGRP,
190 FILE_PERMISSION_READ_BY_OTHERS = S_IROTH,
191 FILE_PERMISSION_WRITE_BY_OTHERS = S_IWOTH,
192 FILE_PERMISSION_EXECUTE_BY_OTHERS = S_IXOTH,
195 // Reads the permission of the given |path|, storing the file permission
196 // bits in |mode|. If |path| is symbolic link, |mode| is the permission of
197 // a file which the symlink points to.
198 BASE_EXPORT bool GetPosixFilePermissions(const FilePath& path, int* mode);
199 // Sets the permission of the given |path|. If |path| is symbolic link, sets
200 // the permission of a file which the symlink points to.
201 BASE_EXPORT bool SetPosixFilePermissions(const FilePath& path, int mode);
203 #endif // OS_POSIX
205 // Returns true if the given directory is empty
206 BASE_EXPORT bool IsDirectoryEmpty(const FilePath& dir_path);
208 // Get the temporary directory provided by the system.
210 // WARNING: In general, you should use CreateTemporaryFile variants below
211 // instead of this function. Those variants will ensure that the proper
212 // permissions are set so that other users on the system can't edit them while
213 // they're open (which can lead to security issues).
214 BASE_EXPORT bool GetTempDir(FilePath* path);
216 // Get the home directory. This is more complicated than just getenv("HOME")
217 // as it knows to fall back on getpwent() etc.
219 // You should not generally call this directly. Instead use DIR_HOME with the
220 // path service which will use this function but cache the value.
221 // Path service may also override DIR_HOME.
222 BASE_EXPORT FilePath GetHomeDir();
224 // Creates a temporary file. The full path is placed in |path|, and the
225 // function returns true if was successful in creating the file. The file will
226 // be empty and all handles closed after this function returns.
227 BASE_EXPORT bool CreateTemporaryFile(FilePath* path);
229 // Same as CreateTemporaryFile but the file is created in |dir|.
230 BASE_EXPORT bool CreateTemporaryFileInDir(const FilePath& dir,
231 FilePath* temp_file);
233 // Create and open a temporary file. File is opened for read/write.
234 // The full path is placed in |path|.
235 // Returns a handle to the opened file or NULL if an error occurred.
236 BASE_EXPORT FILE* CreateAndOpenTemporaryFile(FilePath* path);
238 // Similar to CreateAndOpenTemporaryFile, but the file is created in |dir|.
239 BASE_EXPORT FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir,
240 FilePath* path);
242 // Create a new directory. If prefix is provided, the new directory name is in
243 // the format of prefixyyyy.
244 // NOTE: prefix is ignored in the POSIX implementation.
245 // If success, return true and output the full path of the directory created.
246 BASE_EXPORT bool CreateNewTempDirectory(const FilePath::StringType& prefix,
247 FilePath* new_temp_path);
249 // Create a directory within another directory.
250 // Extra characters will be appended to |prefix| to ensure that the
251 // new directory does not have the same name as an existing directory.
252 BASE_EXPORT bool CreateTemporaryDirInDir(const FilePath& base_dir,
253 const FilePath::StringType& prefix,
254 FilePath* new_dir);
256 // Creates a directory, as well as creating any parent directories, if they
257 // don't exist. Returns 'true' on successful creation, or if the directory
258 // already exists. The directory is only readable by the current user.
259 // Returns true on success, leaving *error unchanged.
260 // Returns false on failure and sets *error appropriately, if it is non-NULL.
261 BASE_EXPORT bool CreateDirectoryAndGetError(const FilePath& full_path,
262 File::Error* error);
264 // Backward-compatible convenience method for the above.
265 BASE_EXPORT bool CreateDirectory(const FilePath& full_path);
267 // Returns the file size. Returns true on success.
268 BASE_EXPORT bool GetFileSize(const FilePath& file_path, int64* file_size);
270 // Sets |real_path| to |path| with symbolic links and junctions expanded.
271 // On windows, make sure the path starts with a lettered drive.
272 // |path| must reference a file. Function will fail if |path| points to
273 // a directory or to a nonexistent path. On windows, this function will
274 // fail if |path| is a junction or symlink that points to an empty file,
275 // or if |real_path| would be longer than MAX_PATH characters.
276 BASE_EXPORT bool NormalizeFilePath(const FilePath& path, FilePath* real_path);
278 #if defined(OS_WIN)
280 // Given a path in NT native form ("\Device\HarddiskVolumeXX\..."),
281 // return in |drive_letter_path| the equivalent path that starts with
282 // a drive letter ("C:\..."). Return false if no such path exists.
283 BASE_EXPORT bool DevicePathToDriveLetterPath(const FilePath& device_path,
284 FilePath* drive_letter_path);
286 // Given an existing file in |path|, set |real_path| to the path
287 // in native NT format, of the form "\Device\HarddiskVolumeXX\..".
288 // Returns false if the path can not be found. Empty files cannot
289 // be resolved with this function.
290 BASE_EXPORT bool NormalizeToNativeFilePath(const FilePath& path,
291 FilePath* nt_path);
292 #endif
294 // This function will return if the given file is a symlink or not.
295 BASE_EXPORT bool IsLink(const FilePath& file_path);
297 // Returns information about the given file path.
298 BASE_EXPORT bool GetFileInfo(const FilePath& file_path, File::Info* info);
300 // Sets the time of the last access and the time of the last modification.
301 BASE_EXPORT bool TouchFile(const FilePath& path,
302 const Time& last_accessed,
303 const Time& last_modified);
305 // Wrapper for fopen-like calls. Returns non-NULL FILE* on success.
306 BASE_EXPORT FILE* OpenFile(const FilePath& filename, const char* mode);
308 // Closes file opened by OpenFile. Returns true on success.
309 BASE_EXPORT bool CloseFile(FILE* file);
311 // Associates a standard FILE stream with an existing File. Note that this
312 // functions take ownership of the existing File.
313 BASE_EXPORT FILE* FileToFILE(File file, const char* mode);
315 // Truncates an open file to end at the location of the current file pointer.
316 // This is a cross-platform analog to Windows' SetEndOfFile() function.
317 BASE_EXPORT bool TruncateFile(FILE* file);
319 // Reads at most the given number of bytes from the file into the buffer.
320 // Returns the number of read bytes, or -1 on error.
321 BASE_EXPORT int ReadFile(const FilePath& filename, char* data, int max_size);
323 // Writes the given buffer into the file, overwriting any data that was
324 // previously there. Returns the number of bytes written, or -1 on error.
325 BASE_EXPORT int WriteFile(const FilePath& filename, const char* data,
326 int size);
328 #if defined(OS_POSIX)
329 // Append the data to |fd|. Does not close |fd| when done.
330 BASE_EXPORT int WriteFileDescriptor(const int fd, const char* data, int size);
331 #endif
333 // Append the given buffer into the file. Returns the number of bytes written,
334 // or -1 on error.
335 BASE_EXPORT int AppendToFile(const FilePath& filename,
336 const char* data, int size);
338 // Gets the current working directory for the process.
339 BASE_EXPORT bool GetCurrentDirectory(FilePath* path);
341 // Sets the current working directory for the process.
342 BASE_EXPORT bool SetCurrentDirectory(const FilePath& path);
344 // Attempts to find a number that can be appended to the |path| to make it
345 // unique. If |path| does not exist, 0 is returned. If it fails to find such
346 // a number, -1 is returned. If |suffix| is not empty, also checks the
347 // existence of it with the given suffix.
348 BASE_EXPORT int GetUniquePathNumber(const FilePath& path,
349 const FilePath::StringType& suffix);
351 #if defined(OS_POSIX)
352 // Test that |path| can only be changed by a given user and members of
353 // a given set of groups.
354 // Specifically, test that all parts of |path| under (and including) |base|:
355 // * Exist.
356 // * Are owned by a specific user.
357 // * Are not writable by all users.
358 // * Are owned by a member of a given set of groups, or are not writable by
359 // their group.
360 // * Are not symbolic links.
361 // This is useful for checking that a config file is administrator-controlled.
362 // |base| must contain |path|.
363 BASE_EXPORT bool VerifyPathControlledByUser(const base::FilePath& base,
364 const base::FilePath& path,
365 uid_t owner_uid,
366 const std::set<gid_t>& group_gids);
367 #endif // defined(OS_POSIX)
369 #if defined(OS_MACOSX) && !defined(OS_IOS)
370 // Is |path| writable only by a user with administrator privileges?
371 // This function uses Mac OS conventions. The super user is assumed to have
372 // uid 0, and the administrator group is assumed to be named "admin".
373 // Testing that |path|, and every parent directory including the root of
374 // the filesystem, are owned by the superuser, controlled by the group
375 // "admin", are not writable by all users, and contain no symbolic links.
376 // Will return false if |path| does not exist.
377 BASE_EXPORT bool VerifyPathControlledByAdmin(const base::FilePath& path);
378 #endif // defined(OS_MACOSX) && !defined(OS_IOS)
380 // Returns the maximum length of path component on the volume containing
381 // the directory |path|, in the number of FilePath::CharType, or -1 on failure.
382 BASE_EXPORT int GetMaximumPathComponentLength(const base::FilePath& path);
384 #if defined(OS_LINUX)
385 // Broad categories of file systems as returned by statfs() on Linux.
386 enum FileSystemType {
387 FILE_SYSTEM_UNKNOWN, // statfs failed.
388 FILE_SYSTEM_0, // statfs.f_type == 0 means unknown, may indicate AFS.
389 FILE_SYSTEM_ORDINARY, // on-disk filesystem like ext2
390 FILE_SYSTEM_NFS,
391 FILE_SYSTEM_SMB,
392 FILE_SYSTEM_CODA,
393 FILE_SYSTEM_MEMORY, // in-memory file system
394 FILE_SYSTEM_CGROUP, // cgroup control.
395 FILE_SYSTEM_OTHER, // any other value.
396 FILE_SYSTEM_TYPE_COUNT
399 // Attempts determine the FileSystemType for |path|.
400 // Returns false if |path| doesn't exist.
401 BASE_EXPORT bool GetFileSystemType(const FilePath& path, FileSystemType* type);
402 #endif
404 #if defined(OS_POSIX)
405 // Get a temporary directory for shared memory files. The directory may depend
406 // on whether the destination is intended for executable files, which in turn
407 // depends on how /dev/shmem was mounted. As a result, you must supply whether
408 // you intend to create executable shmem segments so this function can find
409 // an appropriate location.
410 BASE_EXPORT bool GetShmemTempDir(bool executable, FilePath* path);
411 #endif
413 // Internal --------------------------------------------------------------------
415 namespace internal {
417 // Same as Move but allows paths with traversal components.
418 // Use only with extreme care.
419 BASE_EXPORT bool MoveUnsafe(const FilePath& from_path,
420 const FilePath& to_path);
422 // Same as CopyFile but allows paths with traversal components.
423 // Use only with extreme care.
424 BASE_EXPORT bool CopyFileUnsafe(const FilePath& from_path,
425 const FilePath& to_path);
427 #if defined(OS_WIN)
428 // Copy from_path to to_path recursively and then delete from_path recursively.
429 // Returns true if all operations succeed.
430 // This function simulates Move(), but unlike Move() it works across volumes.
431 // This function is not transactional.
432 BASE_EXPORT bool CopyAndDeleteDirectory(const FilePath& from_path,
433 const FilePath& to_path);
434 #endif // defined(OS_WIN)
436 } // namespace internal
437 } // namespace base
439 #endif // BASE_FILES_FILE_UTIL_H_