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_
+
+#include <string>
+
+#include "base/memory/ref_counted.h"
+#include "content/browser/renderer_host/layered_resource_handler.h"
+#include "third_party/smhasher/src/PMurHash.h"
+#include "webkit/glue/resource_type.h"
+
+namespace net {
+class IOBuffer;
+class URLRequest;
+class URLRequestStatus;
+}
+
+namespace content {
+
+class DuplicateResourceHandler: public LayeredResourceHandler {
+  public:
+  DuplicateResourceHandler(scoped_ptr<ResourceHandler> next_handler,
+                           ResourceType::Type resource_type,
+                           net::URLRequest* request);
+  virtual ~DuplicateResourceHandler();
+
+ private:
+  // ResourceHandler implementation
+  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;
+  virtual bool OnResponseCompleted(int request_id,
+                                   const net::URLRequestStatus& status,
+                                   const std::string& security_info) OVERRIDE;
+
+  ResourceType::Type resource_type_;
+  int bytes_read_;
+  scoped_refptr<net::IOBuffer> read_buffer_;
+  net::URLRequest* request_;
+
+  // These values are temporary values that are used in each digest of the
+  // inputs for the incremental hash (PMurHash).
+  MH_UINT32 pmurhash_ph1_;
+  MH_UINT32 pmurhash_pcarry_;
+
+  DISALLOW_COPY_AND_ASSIGN(DuplicateResourceHandler);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_RENDERER_HOST_DUPLICATE_RESOURCE_HANDLER_H_
+