navigation_entry_screenshot_manager.h revision f2477e01787aa58f445919b809d89e252beef54f
1// Copyright 2013 The Chromium Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style license that can be 3// found in the LICENSE file. 4 5#ifndef CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_SCREENSHOT_MANAGER_H_ 6#define CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_SCREENSHOT_MANAGER_H_ 7 8#include "base/compiler_specific.h" 9#include "base/memory/weak_ptr.h" 10#include "base/time/time.h" 11#include "content/common/content_export.h" 12 13class SkBitmap; 14 15namespace content { 16 17class NavigationControllerImpl; 18class NavigationEntryImpl; 19class RenderViewHost; 20class ScreenshotData; 21 22// NavigationEntryScreenshotManager takes care of taking image-captures for the 23// current navigation entry of a NavigationControllerImpl, and managing these 24// captured images. These image-captures are used for history navigation using 25// overscroll gestures. 26class CONTENT_EXPORT NavigationEntryScreenshotManager { 27 public: 28 explicit NavigationEntryScreenshotManager( 29 NavigationControllerImpl* controller); 30 virtual ~NavigationEntryScreenshotManager(); 31 32 // Takes a screenshot of the last-committed entry of the controller. 33 void TakeScreenshot(); 34 35 // Clears screenshots of all navigation entries. 36 void ClearAllScreenshots(); 37 38 protected: 39 virtual void TakeScreenshotImpl(RenderViewHost* host, 40 NavigationEntryImpl* entry); 41 42 // Called after a screenshot has been set on an NavigationEntryImpl. 43 // Overridden in tests to get notified of when a screenshot is set. 44 virtual void OnScreenshotSet(NavigationEntryImpl* entry); 45 46 NavigationControllerImpl* owner() { return owner_; } 47 48 void SetMinScreenshotIntervalMS(int interval_ms); 49 50 // The callback invoked when taking the screenshot of the page is complete. 51 // This sets the screenshot on the navigation entry. 52 void OnScreenshotTaken(int unique_id, 53 bool success, 54 const SkBitmap& bitmap); 55 56 // Returns the number of entries with screenshots. 57 int GetScreenshotCount() const; 58 59 private: 60 // This is called when the screenshot data has beene encoded to PNG in a 61 // worker thread. 62 void OnScreenshotEncodeComplete(int unique_id, 63 scoped_refptr<ScreenshotData> data); 64 65 // Removes the screenshot for the entry, returning true if the entry had a 66 // screenshot. 67 bool ClearScreenshot(NavigationEntryImpl* entry); 68 69 // The screenshots in the NavigationEntryImpls can accumulate and consume a 70 // large amount of memory. This function makes sure that the memory 71 // consumption is within a certain limit. 72 void PurgeScreenshotsIfNecessary(); 73 74 // The navigation controller that owns this screenshot-manager. 75 NavigationControllerImpl* owner_; 76 77 // Taking a screenshot and encoding them can be async. So use a weakptr for 78 // the callback to make sure that the screenshot/encoding completion callback 79 // does not trigger on a destroyed NavigationEntryScreenshotManager. 80 base::WeakPtrFactory<NavigationEntryScreenshotManager> screenshot_factory_; 81 82 base::Time last_screenshot_time_; 83 int min_screenshot_interval_ms_; 84 85 DISALLOW_COPY_AND_ASSIGN(NavigationEntryScreenshotManager); 86}; 87 88} // namespace content 89 90#endif // CONTENT_BROWSER_FRAME_HOST_NAVIGATION_ENTRY_SCREENSHOT_MANAGER_H_ 91