Precache tracking database

components/precache/content/precache_manager.h

+// Copyright 2013 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 COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_
+#define COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_
+
+#include <list>
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/synchronization/lock.h"
+#include "components/browser_context_keyed_service/browser_context_keyed_service.h"
+#include "components/precache/core/precache_fetcher.h"
+#include "url/gurl.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace precache {
+
+class PrecacheDatabase;
+class URLListProvider;
+
+// Class that manages all precaching-related activities. Owned by the
+// BrowserContext that it is constructed for. Use
+// PrecacheManagerFactory::GetForBrowserContext to get an instance of this
+// class.
+// TODO(sclittle): Delete precache history when browsing history is deleted.
+class PrecacheManager : public BrowserContextKeyedService,
+                        PrecacheFetcher::PrecacheDelegate {
+ public:
+  explicit PrecacheManager(content::BrowserContext* browser_context);
+  virtual ~PrecacheManager();
+
+  // Returns true if precaching is enabled by either Finch or the command line
+  // flag.
+  static bool IsPrecachingEnabled();
+
+  // From BrowserContextKeyedService.
+  virtual void Shutdown() OVERRIDE;
+
+  // From PrecacheFetcher::PrecacheDelegate.
+  virtual void OnDone() OVERRIDE;
+
+  // Starts precaching resources that the user is predicted to fetch in the
+  // future. If precaching is already currently in progress, then this method
+  // does nothing. Must be called on the UI thread.
+  void StartPrecaching(URLListProvider* url_list_provider);
+
+  // Cancels precaching if it is in progress. Must be called on the UI thread.
+  void CancelPrecaching();
+
+  // Returns true if precaching is currently in progress, or false otherwise.
+  // May be called from any thread.
+  bool IsPrecaching();
+
+  // Returns the PrecacheDatabase used for tracking precache metrics. This
+  // method can be called on any thread, but methods on the PrecacheDatabase
+  // should only be used on the DB thread.
+  scoped_refptr<PrecacheDatabase> precache_database();
+
+ private:
+  void OnURLsReceived(const std::list<GURL>& urls);
+
+  // The browser context that owns this PrecacheManager.
+  content::BrowserContext* browser_context_;
+
+  // The PrecacheFetcher used to precache resources. Should only be used on the
+  // UI thread.
+  scoped_ptr<PrecacheFetcher> precache_fetcher_;
+
+  // The PrecacheDatabase for tracking precache metrics. Should only be used on
+  // the DB thread.
+  scoped_refptr<PrecacheDatabase> precache_database_;
+
+  // Flag indicating whether or not precaching is currently in progress.
+  bool is_precaching_;
+
+  // Lock for |is_precaching_|.
+  base::Lock lock_;
+
+  DISALLOW_COPY_AND_ASSIGN(PrecacheManager);
+};
+
+}  // namespace precache
+
+#endif  // COMPONENTS_PRECACHE_CONTENT_PRECACHE_MANAGER_H_