Seculative resource prefetching for URLs CL.

chrome/browser/net/resource_prefetch_interceptor.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 CHROME_BROWSER_NET_RESOURCE_PREFETCH_INTERCEPTOR_H_
+#define CHROME_BROWSER_NET_RESOURCE_PREFETCH_INTERCEPTOR_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "chrome/browser/predictors/resource_prefetch_predictor.h"
+#include "net/url_request/url_request_job_factory.h"

[dominich, 2012/05/21 16:16:53]

nit: this include should be first as it defines the base class.

[Shishir, 2012/05/23 01:46:46]

No longer required.

+
+namespace predictors {
+class URLRequestSummary;
+}
+
+namespace chrome_browser_net {
+
+class ResourcePrefetchInterceptor
+    : public net::URLRequestJobFactory::Interceptor {

[willchan no longer on Chromium, 2012/05/21 20:20:18]

No, do not use this interface. You're not intercepting the URLRequest job
creation in order to replace it with another URLRequestJob. You just want
callbacks at different stages of URLRequest processing so you can record the
data. You should use the NetworkDelegate for this. Do not inherit from this
interface. Instead, write your class to have the appropriate public non-virtual
member functions and add an instance of this class as a member variable in
ChromeNetworkDelegate. In ChromeNetworkDelegate, at the appropriate points,
forward the calls to this class here.

[Shishir, 2012/05/23 01:46:46]

Done,

+ public:
+  explicit ResourcePrefetchInterceptor(
+      scoped_refptr<predictors::ResourcePrefetchPredictor> predictor);
+  virtual ~ResourcePrefetchInterceptor();
+
+ protected:
+  virtual net::URLRequestJob* MaybeIntercept(
+      net::URLRequest* request) const OVERRIDE;
+  virtual net::URLRequestJob* MaybeInterceptResponse(
+      net::URLRequest* request) const OVERRIDE;
+  virtual net::URLRequestJob* MaybeInterceptRedirect(
+      const GURL& location, net::URLRequest* request) const OVERRIDE;
+
+ private:
+  void Intercept(
+      net::URLRequest* request,
+      bool is_response,
+      void(predictors::ResourcePrefetchPredictor::*InterceptFunction)
+      (const predictors::ResourcePrefetchPredictor::URLRequestSummary&)) const;
+
+  scoped_refptr<predictors::ResourcePrefetchPredictor> predictor_;

[willchan no longer on Chromium, 2012/05/21 20:20:18]

Does ResourcePrefetchInterceptor own predictors::ResourcePrefetchPredictor? I
assume so, since it's holding a reference to ResourcePrefetchPredictor. This
confuses me, because ResourcePrefetchPredictor looks like it's owned by the
Profile. Do you have a ownership reference cycle?

[Shishir, 2012/05/23 01:46:46]

ResourcePrefetchPredictor is refcounted as it needs to be accessed both in the
UI and in the IO threads. Most of its functions need to be called in the UI
thread, but I need to have a pointer to it in the IO thread from where I post
tasks to it.

I don't think there is a cycle here as the predictor itself does not hold a
refcounted reference to anything.

+
+  DISALLOW_COPY_AND_ASSIGN(ResourcePrefetchInterceptor);
+};
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_RESOURCE_PREFETCH_INTERCEPTOR_H_