Implementing preload=metadata for video

webkit/glue/media/buffered_resource_loader.h

Index: webkit/glue/media/buffered_resource_loader.h
diff --git a/webkit/glue/media/buffered_resource_loader.h b/webkit/glue/media/buffered_resource_loader.h
index fe01fb4d3cfa88be1f84f7b73cfc9b1f077fff97..d03e9d03858f9f0680bc873e9229cfca888dc36d 100644
--- a/webkit/glue/media/buffered_resource_loader.h
+++ b/webkit/glue/media/buffered_resource_loader.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2010 The Chromium Authors. All rights reserved.
+// Copyright (c) 2011 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.
 
@@ -28,6 +28,7 @@ const char kHttpScheme[] = "http";
 const char kHttpsScheme[] = "https";
 const char kDataScheme[] = "data";
 
+class BufferedDataSource;

[acolwell GONE FROM CHROMIUM, 2011/03/25 23:08:14]

No longer necessary.

[vrk (LEFT CHROMIUM), 2011/03/29 00:53:00]

Done.

 // This class works inside demuxer thread and render thread. It contains a
 // WebURLLoader and does the actual resource loading. This object does
 // buffering internally, it defers the resource loading if buffer is full
@@ -36,6 +37,12 @@ class BufferedResourceLoader :
     public base::RefCountedThreadSafe<BufferedResourceLoader>,
     public WebKit::WebURLLoaderClient {
  public:
+  enum DeferStrategy {

[acolwell GONE FROM CHROMIUM, 2011/03/25 23:08:14]

Brief comments about each of these.

[vrk (LEFT CHROMIUM), 2011/03/29 00:53:00]

Done.

I also changed the naming style to match the style of the State enum in
pipeline_impl.h, but the convention is different in pipeline_status.h? Style
guide is a little ambiguous; I could read it saying we only use MACRO_STYLE or
either is OK based on what existing code was doing?

[acolwell GONE FROM CHROMIUM, 2011/03/29 05:52:03]

I think the kXXX style is good here. I think PipelineStatus is MACRO_STYLE
because it looks more like error code macros  in Unix & Windows. I don't know
the history, but that would be my guess.
On 2011/03/29 00:53:00, Victoria Kirst wrote:

+    NeverDefer,
+    ReadThenDefer,
+    ThresholdDefer
+  };
+
   typedef Callback0::Type NetworkEventCallback;
 
   // |url| - URL for the resource to be loaded.
@@ -85,9 +92,6 @@ class BufferedResourceLoader :
   // |kPositionNotSpecified| if such value is not available.
   virtual int64 GetBufferedPosition();
 
-  // Sets whether deferring data is allowed or disallowed.
-  virtual void SetAllowDefer(bool is_allowed);
-
   // Gets the content length in bytes of the instance after this loader has been
   // started. If this value is |kPositionNotSpecified|, then content length is
   // unknown.
@@ -141,19 +145,30 @@ class BufferedResourceLoader :
 
   bool HasSingleOrigin() const;
 
+  void SetDeferStrategy(DeferStrategy strategy);
+
+  // Updates deferring behavior based on current buffering scheme.
+  void UpdateDeferBehavior();

[acolwell GONE FROM CHROMIUM, 2011/03/25 23:08:14]

I believe this can become private once the one call in BufferedDataSource gets
moved to SetDeferStrategy().

[vrk (LEFT CHROMIUM), 2011/03/29 00:53:00]

Done.

+
  protected:
   friend class base::RefCountedThreadSafe<BufferedResourceLoader>;
-
   virtual ~BufferedResourceLoader();
 
  private:
+

[acolwell GONE FROM CHROMIUM, 2011/03/25 23:08:14]

Remove blank line

[vrk (LEFT CHROMIUM), 2011/03/29 00:53:00]

Done.

   friend class BufferedResourceLoaderTest;
 
-  // Defer the resource loading if the buffer is full.
-  void EnableDeferIfNeeded();
+  // Toggles whether the resource loading is deferred or not.
+  // Returns true if a network event was fired.
+  bool ToggleDeferring();
+
+  // Returns true if we should defer resource loading, based
+  // on current buffering scheme.
+  bool ShouldEnableDefer();
 
-  // Disable defer loading if we are under-buffered.
-  void DisableDeferIfNeeded();
+  // Returns true if we should enable resource loading, based
+  // on current buffering scheme.
+  bool ShouldDisableDefer();
 
   // Returns true if the current read request can be fulfilled by what is in
   // the buffer.
@@ -196,8 +211,7 @@ class BufferedResourceLoader :
   // True if resource loading was deferred.
   bool deferred_;
 
-  // True if resource loader is allowed to defer, false otherwise.
-  bool defer_allowed_;
+  DeferStrategy defer_strategy_;
 
   // True if resource loading has completed.
   bool completed_;