Adding some functions that operate on file handles.

TEST=platform_file_unittest.cc
BUG=none
TBR=darin

Review URL: http://codereview.chromium.org/3354020

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@59041 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 27 insertions, 1 deletions

diff --git a/base/platform_file.h b/base/platform_file.h
index 802102c..abe5cdd 100644
--- a/base/platform_file.h
+++ b/base/platform_file.h
@@ -40,7 +40,8 @@ enum PlatformFileFlags {
   PLATFORM_FILE_TEMPORARY = 512,        // Used on Windows only
   PLATFORM_FILE_HIDDEN = 1024,          // Used on Windows only
   PLATFORM_FILE_DELETE_ON_CLOSE = 2048,
-  PLATFORM_FILE_TRUNCATE = 4096
+  PLATFORM_FILE_TRUNCATE = 4096,
+  PLATFORM_FILE_WRITE_ATTRIBUTES = 8192 // Used on Windows only
 };
 
 enum PlatformFileError {
@@ -94,6 +95,31 @@ PlatformFile CreatePlatformFile(const std::wstring& name,
 // Closes a file handle
 bool ClosePlatformFile(PlatformFile file);
 
+// 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.
+int ReadPlatformFile(PlatformFile file, int64 offset, 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.
+int WritePlatformFile(PlatformFile file, int64 offset,
+                      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.
+bool TruncatePlatformFile(PlatformFile file, int64 length);
+
+// Flushes the buffers of the given file.
+bool FlushPlatformFile(PlatformFile file);
+
+// Touches the given file.
+bool TouchPlatformFile(PlatformFile file, const Time& last_access_time,
+                       const Time& last_modified_time);
+
+// Returns some information for the given file.
+bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info);
+
 // Use this class to pass ownership of a PlatformFile to a receiver that may or
 // may not want to accept it.  This class does not own the storage for the
 // PlatformFile.