Record UMA statistics for file_stream operations.

net/base/file_stream.h

Index: net/base/file_stream.h
diff --git a/net/base/file_stream.h b/net/base/file_stream.h
index 5e07adcf6a703714a5919dfd2ad0689bc7b92e35..60b33bce752cd3fa67ee5fc9f910d474c878e212 100644
--- a/net/base/file_stream.h
+++ b/net/base/file_stream.h
@@ -20,6 +20,29 @@ class FilePath;
 
 namespace net {
 
+enum RecordingClass {

[cbentzel, 2011/08/15 19:49:11]

This CL would be a lot easier without the RecordingClass. It doesn't seem to add
much, and I'd strongly recommend removing it. I definitely want to see the
global removed.

[ahendrickson, 2011/08/15 23:42:26]

Done.

+  RECORDING_CLASS_NONE = 0,
+  RECORDING_CLASS_DOWNLOADS = 1,
+  // Add more flags here as necessary.  Max 31.
+  RECORDING_CLASS_MAX,
+};
+
+enum FileErrorTypes {

[cbentzel, 2011/08/15 19:49:11]

This doesn't need to be exposed in this header - it's internal to the
implementation of file_stream. If you want it to be shared, move it to a
file_stream_metrics.h header which only file_stream_posix and file_stream_win
include.

[cbentzel, 2011/08/15 19:49:11]

Nit: maybe FileError rather than FileErrorTypes

[ahendrickson, 2011/08/15 23:42:26]

Renamed to FileErrorSource.

[ahendrickson, 2011/08/15 23:42:26]

Done.

+  FILE_ERROR_TYPES_IS_NOT_OPEN = 0,
+  FILE_ERROR_TYPES_OPEN,
+  FILE_ERROR_TYPES_WRITE,
+  FILE_ERROR_TYPES_READ,
+  FILE_ERROR_TYPES_SEEK,
+  FILE_ERROR_TYPES_FLUSH,
+  FILE_ERROR_TYPES_SET_EOF,
+  FILE_ERROR_TYPES_GET_SIZE,
+  FILE_ERROR_TYPES_COUNT,
+};
+
+void EnableRecordingForClass(int class_flags);
+
+void RecordFileError(int error, FileErrorTypes type, int class_flags);

[cbentzel, 2011/08/15 19:49:11]

This would also move to the new header.

[ahendrickson, 2011/08/15 23:42:26]

Done.

+
 // TODO(darin): Move this to a more generic location.
 // This explicit mapping matches both FILE_ on Windows and SEEK_ on Linux.
 enum Whence {
@@ -31,6 +54,7 @@ enum Whence {
 class NET_API FileStream {
  public:
   FileStream();
+  explicit FileStream(int class_flags);

[cbentzel, 2011/08/15 19:49:11]

Remove the new constructors and just use EnableRecording. 

[ahendrickson, 2011/08/15 23:42:26]

Done.

 
   // Construct a FileStream with an existing file handle and opening flags.
   // |file| is valid file handle.
@@ -40,6 +64,14 @@ class NET_API FileStream {
   // is destructed.
   FileStream(base::PlatformFile file, int flags);
 
+  // Construct a FileStream with an existing file handle and opening flags.

[cbentzel, 2011/08/15 19:49:11]

Ditto. 

[ahendrickson, 2011/08/15 23:42:26]

Done.

+  // |file| is valid file handle.
+  // |flags| is a bitfield of base::PlatformFileFlags when the file handle was
+  // opened.
+  // The already opened file will not be automatically closed when FileStream
+  // is destructed.
+  FileStream(base::PlatformFile file, int flags, int class_flags);
+
   ~FileStream();
 
   // Call this method to close the FileStream.  It is OK to call Close
@@ -132,6 +164,8 @@ class NET_API FileStream {
   // This method should not be called if the stream was opened READ_ONLY.
   int Flush();
 
+  void EnableRecording(bool enable, int class_flags);

[cbentzel, 2011/08/15 19:49:11]

Just make this 

void EnableRecording();

enable is never non-true by callers. If you really want to include |class_flags|
you can.

Also, document this method.

[ahendrickson, 2011/08/15 23:42:26]

Done.

+
  private:
   class AsyncContext;
   friend class AsyncContext;
@@ -143,6 +177,7 @@ class NET_API FileStream {
   base::PlatformFile file_;
   int open_flags_;
   bool auto_closed_;
+  int class_flags_;
 
   DISALLOW_COPY_AND_ASSIGN(FileStream);
 };