net: Implement canceling of all async operations in FileStream.

base/platform_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_PLATFORM_FILE_H_
 #define BASE_PLATFORM_FILE_H_
 
 #include "build/build_config.h"
 #if defined(OS_WIN)
 #include <windows.h>
@@ skipping 60 matching lines @@
   PLATFORM_FILE_ERROR_NO_SPACE = -8,
   PLATFORM_FILE_ERROR_NOT_A_DIRECTORY = -9,
   PLATFORM_FILE_ERROR_INVALID_OPERATION = -10,
   PLATFORM_FILE_ERROR_SECURITY = -11,
   PLATFORM_FILE_ERROR_ABORT = -12,
   PLATFORM_FILE_ERROR_NOT_A_FILE = -13,
   PLATFORM_FILE_ERROR_NOT_EMPTY = -14,
   PLATFORM_FILE_ERROR_INVALID_URL = -15,
 };
 
+// This explicit mapping matches both FILE_ on Windows and SEEK_ on Linux.
+enum PlatformFileWhence {
+  PLATFORM_FILE_FROM_BEGIN   = 0,
+  PLATFORM_FILE_FROM_CURRENT = 1,
+  PLATFORM_FILE_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::PlatformFileInfo> implementation in
 // chrome/common/common_param_traits.cc.
 struct BASE_EXPORT PlatformFileInfo {
   PlatformFileInfo();
   ~PlatformFileInfo();
 
   // The size of the file in bytes.  Undefined when is_directory is true.
@@ skipping 20 matching lines @@
 // simulate a new file, which can happen with PLATFORM_FILE_CREATE_ALWAYS], and
 // false otherwise.  |error_code| can be NULL.
 BASE_EXPORT PlatformFile CreatePlatformFile(const FilePath& name,
                                             int flags,
                                             bool* created,
                                             PlatformFileError* error_code);
 
 // Closes a file handle. Returns |true| on success and |false| otherwise.
 BASE_EXPORT bool ClosePlatformFile(PlatformFile file);
 
+// 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.
+BASE_EXPORT int64 SeekPlatformFile(PlatformFile file,
+                                   PlatformFileWhence 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.
 BASE_EXPORT int ReadPlatformFile(PlatformFile file, int64 offset,
                                  char* data, int size);
 
 // Same as above but without seek.
 BASE_EXPORT int ReadPlatformFileAtCurrentPos(PlatformFile file,
                                              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.
 BASE_EXPORT int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
                                              char* data, int size);
 
+// Same as above but without seek.
+BASE_EXPORT int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
+                                                   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.
 BASE_EXPORT int WritePlatformFile(PlatformFile file, int64 offset,
                                   const char* data, int size);
 
 // Save as above but without seek.
 BASE_EXPORT int WritePlatformFileAtCurrentPos(PlatformFile file,
                                               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.
+BASE_EXPORT int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
+                                                    const char* data, int size);
+
 // Truncates the given 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.
 BASE_EXPORT bool TruncatePlatformFile(PlatformFile file, int64 length);
 
 // Flushes the buffers of the given file.
 BASE_EXPORT bool FlushPlatformFile(PlatformFile file);
 
 // Touches the given file.
 BASE_EXPORT bool TouchPlatformFile(PlatformFile file,
@@ skipping 37 matching lines @@
     return temp;
   }
 
  private:
   PlatformFile* value_;
 };
 
 }  // namespace base
 
 #endif  // BASE_PLATFORM_FILE_H_