Move base to DEPS

base/files/file.h

-// Copyright (c) 2012 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_FILES_FILE_H_
-#define BASE_FILES_FILE_H_
-
-#include "build/build_config.h"
-#if defined(OS_WIN)
-#include <windows.h>
-#endif
-
-#if defined(OS_POSIX)
-#include <sys/stat.h>
-#endif
-
-#include <string>
-
-#include "base/base_export.h"
-#include "base/basictypes.h"
-#include "base/files/file_path.h"
-#include "base/files/file_tracing.h"
-#include "base/files/scoped_file.h"
-#include "base/gtest_prod_util.h"
-#include "base/move.h"
-#include "base/time/time.h"
-
-#if defined(OS_WIN)
-#include "base/win/scoped_handle.h"
-#endif
-
-FORWARD_DECLARE_TEST(FileTest, MemoryCorruption);
-
-namespace base {
-
-#if defined(OS_WIN)
-typedef HANDLE PlatformFile;
-#elif defined(OS_POSIX)
-typedef int PlatformFile;
-
-#if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)
-typedef struct stat stat_wrapper_t;
-#else
-typedef struct stat64 stat_wrapper_t;
-#endif
-#endif  // defined(OS_POSIX)
-
-// Thin wrapper around an OS-level file.
-// Note that this class does not provide any support for asynchronous IO, other
-// than the ability to create asynchronous handles on Windows.
-//
-// Note about const: this class does not attempt to determine if the underlying
-// file system object is affected by a particular method in order to consider
-// that method const or not. Only methods that deal with member variables in an
-// obvious non-modifying way are marked as const. Any method that forward calls
-// to the OS is not considered const, even if there is no apparent change to
-// member variables.
-class BASE_EXPORT File {
-  MOVE_ONLY_TYPE_FOR_CPP_03(File, RValue)
-
- public:
-  // FLAG_(OPEN|CREATE).* are mutually exclusive. You should specify exactly one
-  // of the five (possibly combining with other flags) when opening or creating
-  // a file.
-  // FLAG_(WRITE|APPEND) are mutually exclusive. This is so that APPEND behavior
-  // will be consistent with O_APPEND on POSIX.
-  // FLAG_EXCLUSIVE_(READ|WRITE) only grant exclusive access to the file on
-  // creation on POSIX; for existing files, consider using Lock().
-  enum Flags {
-    FLAG_OPEN = 1 << 0,             // Opens a file, only if it exists.
-    FLAG_CREATE = 1 << 1,           // Creates a new file, only if it does not
-                                    // already exist.
-    FLAG_OPEN_ALWAYS = 1 << 2,      // May create a new file.
-    FLAG_CREATE_ALWAYS = 1 << 3,    // May overwrite an old file.
-    FLAG_OPEN_TRUNCATED = 1 << 4,   // Opens a file and truncates it, only if it
-                                    // exists.
-    FLAG_READ = 1 << 5,
-    FLAG_WRITE = 1 << 6,
-    FLAG_APPEND = 1 << 7,
-    FLAG_EXCLUSIVE_READ = 1 << 8,   // EXCLUSIVE is opposite of Windows SHARE.
-    FLAG_EXCLUSIVE_WRITE = 1 << 9,
-    FLAG_ASYNC = 1 << 10,
-    FLAG_TEMPORARY = 1 << 11,       // Used on Windows only.
-    FLAG_HIDDEN = 1 << 12,          // Used on Windows only.
-    FLAG_DELETE_ON_CLOSE = 1 << 13,
-    FLAG_WRITE_ATTRIBUTES = 1 << 14,  // Used on Windows only.
-    FLAG_SHARE_DELETE = 1 << 15,      // Used on Windows only.
-    FLAG_TERMINAL_DEVICE = 1 << 16,   // Serial port flags.
-    FLAG_BACKUP_SEMANTICS = 1 << 17,  // Used on Windows only.
-    FLAG_EXECUTE = 1 << 18,           // Used on Windows only.
-  };
-
-  // This enum has been recorded in multiple histograms. If the order of the
-  // fields needs to change, please ensure that those histograms are obsolete or
-  // have been moved to a different enum.
-  //
-  // FILE_ERROR_ACCESS_DENIED is returned when a call fails because of a
-  // filesystem restriction. FILE_ERROR_SECURITY is returned when a browser
-  // policy doesn't allow the operation to be executed.
-  enum Error {
-    FILE_OK = 0,
-    FILE_ERROR_FAILED = -1,
-    FILE_ERROR_IN_USE = -2,
-    FILE_ERROR_EXISTS = -3,
-    FILE_ERROR_NOT_FOUND = -4,
-    FILE_ERROR_ACCESS_DENIED = -5,
-    FILE_ERROR_TOO_MANY_OPENED = -6,
-    FILE_ERROR_NO_MEMORY = -7,
-    FILE_ERROR_NO_SPACE = -8,
-    FILE_ERROR_NOT_A_DIRECTORY = -9,
-    FILE_ERROR_INVALID_OPERATION = -10,
-    FILE_ERROR_SECURITY = -11,
-    FILE_ERROR_ABORT = -12,
-    FILE_ERROR_NOT_A_FILE = -13,
-    FILE_ERROR_NOT_EMPTY = -14,
-    FILE_ERROR_INVALID_URL = -15,
-    FILE_ERROR_IO = -16,
-    // Put new entries here and increment FILE_ERROR_MAX.
-    FILE_ERROR_MAX = -17
-  };
-
-  // This explicit mapping matches both FILE_ on Windows and SEEK_ on Linux.
-  enum Whence {
-    FROM_BEGIN   = 0,
-    FROM_CURRENT = 1,
-    FROM_END     = 2
-  };
-
-  // Used to hold information about a given file.
-  // If you add more fields to this structure (platform-specific fields are OK),
-  // make sure to update all functions that use it in file_util_{win|posix}.cc,
-  // too, and the ParamTraits<base::File::Info> implementation in
-  // ipc/ipc_message_utils.cc.
-  struct BASE_EXPORT Info {
-    Info();
-    ~Info();
-#if defined(OS_POSIX)
-    // Fills this struct with values from |stat_info|.
-    void FromStat(const stat_wrapper_t& stat_info);
-#endif
-
-    // The size of the file in bytes.  Undefined when is_directory is true.
-    int64 size;
-
-    // True if the file corresponds to a directory.
-    bool is_directory;
-
-    // True if the file corresponds to a symbolic link.  For Windows currently
-    // not supported and thus always false.
-    bool is_symbolic_link;
-
-    // The last modified time of a file.
-    Time last_modified;
-
-    // The last accessed time of a file.
-    Time last_accessed;
-
-    // The creation time of a file.
-    Time creation_time;
-  };
-
-  File();
-
-  // Creates or opens the given file. This will fail with 'access denied' if the
-  // |path| contains path traversal ('..') components.
-  File(const FilePath& path, uint32 flags);
-
-  // Takes ownership of |platform_file|.
-  explicit File(PlatformFile platform_file);
-
-  // Creates an object with a specific error_details code.
-  explicit File(Error error_details);
-
-  // Move constructor for C++03 move emulation of this type.
-  File(RValue other);
-
-  ~File();
-
-  // Takes ownership of |platform_file|.
-  static File CreateForAsyncHandle(PlatformFile platform_file);
-
-  // Move operator= for C++03 move emulation of this type.
-  File& operator=(RValue other);
-
-  // Creates or opens the given file.
-  void Initialize(const FilePath& path, uint32 flags);
-
-  bool IsValid() const;
-
-  // Returns true if a new file was created (or an old one truncated to zero
-  // length to simulate a new file, which can happen with
-  // FLAG_CREATE_ALWAYS), and false otherwise.
-  bool created() const { return created_; }
-
-  // Returns the OS result of opening this file. Note that the way to verify
-  // the success of the operation is to use IsValid(), not this method:
-  //   File file(path, flags);
-  //   if (!file.IsValid())
-  //     return;
-  Error error_details() const { return error_details_; }
-
-  PlatformFile GetPlatformFile() const;
-  PlatformFile TakePlatformFile();
-
-  // Destroying this object closes the file automatically.
-  void Close();
-
-  // Changes current position in the file to an |offset| relative to an origin
-  // defined by |whence|. Returns the resultant current position in the file
-  // (relative to the start) or -1 in case of error.
-  int64 Seek(Whence whence, int64 offset);
-
-  // Reads the given number of bytes (or until EOF is reached) starting with the
-  // given offset. Returns the number of bytes read, or -1 on error. Note that
-  // this function makes a best effort to read all data on all platforms, so it
-  // is not intended for stream oriented files but instead for cases when the
-  // normal expectation is that actually |size| bytes are read unless there is
-  // an error.
-  int Read(int64 offset, char* data, int size);
-
-  // Same as above but without seek.
-  int ReadAtCurrentPos(char* data, int size);
-
-  // Reads the given number of bytes (or until EOF is reached) starting with the
-  // given offset, but does not make any effort to read all data on all
-  // platforms. Returns the number of bytes read, or -1 on error.
-  int ReadNoBestEffort(int64 offset, char* data, int size);
-
-  // Same as above but without seek.
-  int ReadAtCurrentPosNoBestEffort(char* data, int size);
-
-  // Writes the given buffer into the file at the given offset, overwritting any
-  // data that was previously there. Returns the number of bytes written, or -1
-  // on error. Note that this function makes a best effort to write all data on
-  // all platforms.
-  // Ignores the offset and writes to the end of the file if the file was opened
-  // with FLAG_APPEND.
-  int Write(int64 offset, const char* data, int size);
-
-  // Save as above but without seek.
-  int WriteAtCurrentPos(const char* data, int size);
-
-  // Save as above but does not make any effort to write all data on all
-  // platforms. Returns the number of bytes written, or -1 on error.
-  int WriteAtCurrentPosNoBestEffort(const char* data, int size);
-
-  // Returns the current size of this file, or a negative number on failure.
-  int64 GetLength();
-
-  // Truncates the file to the given length. If |length| is greater than the
-  // current size of the file, the file is extended with zeros. If the file
-  // doesn't exist, |false| is returned.
-  bool SetLength(int64 length);
-
-  // Instructs the filesystem to flush the file to disk. (POSIX: fsync, Windows:
-  // FlushFileBuffers).
-  bool Flush();
-
-  // Updates the file times.
-  bool SetTimes(Time last_access_time, Time last_modified_time);
-
-  // Returns some basic information for the given file.
-  bool GetInfo(Info* info);
-
-  // Attempts to take an exclusive write lock on the file. Returns immediately
-  // (i.e. does not wait for another process to unlock the file). If the lock
-  // was obtained, the result will be FILE_OK. A lock only guarantees
-  // that other processes may not also take a lock on the same file with the
-  // same API - it may still be opened, renamed, unlinked, etc.
-  //
-  // Common semantics:
-  //  * Locks are held by processes, but not inherited by child processes.
-  //  * Locks are released by the OS on file close or process termination.
-  //  * Locks are reliable only on local filesystems.
-  //  * Duplicated file handles may also write to locked files.
-  // Windows-specific semantics:
-  //  * Locks are mandatory for read/write APIs, advisory for mapping APIs.
-  //  * Within a process, locking the same file (by the same or new handle)
-  //    will fail.
-  // POSIX-specific semantics:
-  //  * Locks are advisory only.
-  //  * Within a process, locking the same file (by the same or new handle)
-  //    will succeed.
-  //  * Closing any descriptor on a given file releases the lock.
-  Error Lock();
-
-  // Unlock a file previously locked.
-  Error Unlock();
-
-  // Returns a new object referencing this file for use within the current
-  // process. Handling of FLAG_DELETE_ON_CLOSE varies by OS. On POSIX, the File
-  // object that was created or initialized with this flag will have unlinked
-  // the underlying file when it was created or opened. On Windows, the
-  // underlying file is deleted when the last handle to it is closed.
-  File Duplicate();
-
-  bool async() const { return async_; }
-
-#if defined(OS_WIN)
-  static Error OSErrorToFileError(DWORD last_error);
-#elif defined(OS_POSIX)
-  static Error OSErrorToFileError(int saved_errno);
-#endif
-
-  // Converts an error value to a human-readable form. Used for logging.
-  static std::string ErrorToString(Error error);
-
- private:
-  FRIEND_TEST_ALL_PREFIXES(::FileTest, MemoryCorruption);
-
-  friend class FileTracing::ScopedTrace;
-
-#if defined(OS_POSIX)
-  // Encloses a single ScopedFD, saving a cheap tamper resistent memory checksum
-  // alongside it. This checksum is validated at every access, allowing early
-  // detection of memory corruption.
-
-  // TODO(gavinp): This is in place temporarily to help us debug
-  // https://crbug.com/424562 , which can't be reproduced in valgrind. Remove
-  // this code after we have fixed this issue.
-  class MemoryCheckingScopedFD {
-   public:
-    MemoryCheckingScopedFD();
-    MemoryCheckingScopedFD(int fd);
-    ~MemoryCheckingScopedFD();
-
-    bool is_valid() const { Check(); return file_.is_valid(); }
-    int get() const { Check(); return file_.get(); }
-
-    void reset() { Check(); file_.reset(); UpdateChecksum(); }
-    void reset(int fd) { Check(); file_.reset(fd); UpdateChecksum(); }
-    int release() {
-      Check();
-      int fd = file_.release();
-      UpdateChecksum();
-      return fd;
-    }
-
-   private:
-    FRIEND_TEST_ALL_PREFIXES(::FileTest, MemoryCorruption);
-
-    // Computes the checksum for the current value of |file_|. Returns via an
-    // out parameter to guard against implicit conversions of unsigned integral
-    // types.
-    void ComputeMemoryChecksum(unsigned int* out_checksum) const;
-
-    // Confirms that the current |file_| and |file_memory_checksum_| agree,
-    // failing a CHECK if they do not.
-    void Check() const;
-
-    void UpdateChecksum();
-
-    ScopedFD file_;
-    unsigned int file_memory_checksum_;
-  };
-#endif
-
-  // Creates or opens the given file. Only called if |path| has no
-  // traversal ('..') components.
-  void DoInitialize(const FilePath& path, uint32 flags);
-
-  // TODO(tnagel): Reintegrate into Flush() once histogram isn't needed anymore,
-  // cf. issue 473337.
-  bool DoFlush();
-
-  void SetPlatformFile(PlatformFile file);
-
-#if defined(OS_WIN)
-  win::ScopedHandle file_;
-#elif defined(OS_POSIX)
-  MemoryCheckingScopedFD file_;
-#endif
-
-  // A path to use for tracing purposes. Set if file tracing is enabled during
-  // |Initialize()|.
-  FilePath tracing_path_;
-
-  // Object tied to the lifetime of |this| that enables/disables tracing.
-  FileTracing::ScopedEnabler trace_enabler_;
-
-  Error error_details_;
-  bool created_;
-  bool async_;
-};
-
-}  // namespace base
-
-#endif  // BASE_FILES_FILE_H_