DuplicateContentResourceHandler to monitor resources and track how many times th…

content/browser/renderer_host/duplicate_resource_handler.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 CONTENT_BROWSER_RENDERER_HOST_DUPLICATE_RESOURCE_HANDLER_H_
+#define CONTENT_BROWSER_RENDERER_HOST_DUPLICATE_RESOURCE_HANDLER_H_
+#pragma once
+
+#include <set>
+
+#include "base/memory/ref_counted.h"
+#include "content/browser/renderer_host/layered_resource_handler.h"
+
+namespace net {
+class IOBuffer;
+class URLRequest;
+}
+
+namespace content {
+
+class DuplicateResourceHandler: public LayeredResourceHandler {
+
+ public:
+  DuplicateResourceHandler(scoped_ptr<ResourceHandler> next_handler,
+                           net::URLRequest* request);
+  virtual ~DuplicateResourceHandler();
+
+ private:
+  enum { kReadBufSize = 4000 };

[frankwang, 2012/07/12 21:50:36]

I set the buffer size to be 4000. In other handlers, the buffer sizes seem to
vary. I don't know what the best one to use is. I think only look at the first
4000 bytes of a resource might actually be fine. 

+
+  // ResourceHandler implementation
+  virtual bool OnWillStart(int request_id, const GURL& url, 
+                           bool* defer) OVERRIDE;
+  virtual bool OnWillRead(int request_id,
+                          net::IOBuffer** buf,
+                          int* buf_size,
+                          int min_size) OVERRIDE;
+  virtual bool OnReadCompleted(int request_id, int bytes_read,
+                               bool* defer) OVERRIDE;
+
+  int bytes_hit_; // bytes that hit element in cache
+  int bytes_miss_; // bytes that miss element in cache
+  int read_buffer_size_;
+  scoped_refptr<net::IOBuffer> read_buffer_;
+  net::URLRequest* request_;
+
+  DISALLOW_COPY_AND_ASSIGN(DuplicateResourceHandler);
+};  // class DuplicateResourceHandler
+
+}  // namespace content
+
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_DUPLICATE_RESOURCE_HANDLER_H_