1 // Copyright (c) 2011 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 CHROME_BROWSER_INSTANT_INSTANT_LOADER_MANAGER_H_ 6 #define CHROME_BROWSER_INSTANT_INSTANT_LOADER_MANAGER_H_ 7 #pragma once 8 9 #include <map> 10 11 #include "base/memory/scoped_ptr.h" 12 #include "chrome/browser/search_engines/template_url_id.h" 13 14 class InstantLoader; 15 class InstantLoaderDelegate; 16 17 // InstantLoaderManager is responsible for maintaining the InstantLoaders for 18 // InstantController. InstantLoaderManager keeps track of one loader for loading 19 // non-instant urls, and a loader per TemplateURLID for loading instant urls. A 20 // loader per TemplateURLID is necessitated due to not knowing in advance if a 21 // site really supports instant (for example, the user might have opted out even 22 // though it's supported). 23 // 24 // Users of InstantLoaderManager need only concern themselves with the current 25 // and pending loaders. The current loader is the loader that if ready is shown 26 // by InstantController. The pending loader is used if the current loader is 27 // ready and update is invoked with a different id. In this case the current 28 // loader is left as current (and it's preview contents stopped) and the newly 29 // created loader is set to pending. Once the pending loader is ready 30 // MakePendingCurrent should be invoked to make the pending the current loader. 31 // 32 // InstantLoader owns all the InstantLoaders returned. You can take 33 // ownership of the current loader by invoking ReleaseCurrentLoader. 34 class InstantLoaderManager { 35 public: 36 explicit InstantLoaderManager(InstantLoaderDelegate* loader_delegate); 37 ~InstantLoaderManager(); 38 39 // Updates the current loader. If the current loader is replaced and should be 40 // deleted it is set in |old_loader|. This is done to allow the caller to 41 // notify delegates before the old loader is destroyed. This returns the 42 // active InstantLoader that should be used. 43 InstantLoader* UpdateLoader(TemplateURLID instant_id, 44 scoped_ptr<InstantLoader>* old_loader); 45 46 // Returns true if invoking |UpdateLoader| with |instant_id| would change the 47 // active loader. 48 bool WillUpateChangeActiveLoader(TemplateURLID instant_id); 49 50 // Makes the pending loader the current loader. If ownership of the old 51 // loader is to pass to the caller |old_loader| is set appropriately. 52 void MakePendingCurrent(scoped_ptr<InstantLoader>* old_loader); 53 54 // Returns the current loader and clears internal references to it. This 55 // should be used prior to destroying the InstantLoaderManager when the owner 56 // of InstantLoaderManager wants to take ownership of the loader. 57 InstantLoader* ReleaseCurrentLoader(); 58 59 // Destroys the specified loader. 60 void DestroyLoader(InstantLoader* loader); 61 62 // Removes references to loader. 63 InstantLoader* ReleaseLoader(InstantLoader* loader); 64 65 // If |loader| is in |instant_loaders_| it is removed. 66 void RemoveLoaderFromInstant(InstantLoader* loader); 67 68 // Returns the current loader, may be null. 69 InstantLoader* current_loader() const { return current_loader_; } 70 71 // Returns the pending loader, may be null. 72 InstantLoader* pending_loader() const { return pending_loader_; } 73 74 // The active loader is the loader that should be used for new loads. It is 75 // either the pending loader or the current loader. 76 InstantLoader* active_loader() const { 77 return pending_loader_ ? pending_loader_ : current_loader_; 78 } 79 80 // Returns the number of instant loaders. 81 // This is exposed for tests. 82 size_t num_instant_loaders() const { return instant_loaders_.size(); } 83 84 private: 85 typedef std::map<TemplateURLID, InstantLoader*> Loaders; 86 87 // Creates a loader and if |id| is non-zero registers it in instant_loaders_. 88 InstantLoader* CreateLoader(TemplateURLID id); 89 90 // Returns the loader for loading instant results with the specified id. If 91 // there is no loader for the specified id a new one is created. 92 InstantLoader* GetInstantLoader(TemplateURLID id); 93 94 InstantLoaderDelegate* loader_delegate_; 95 96 // The current loader. 97 InstantLoader* current_loader_; 98 99 // Loader we want to use as soon as ready. This is only non-null if 100 // current_loader_ is ready and Update is invoked with a different template 101 // url id. 102 InstantLoader* pending_loader_; 103 104 // Maps for template url id to loader used for that template url id. 105 Loaders instant_loaders_; 106 107 DISALLOW_COPY_AND_ASSIGN(InstantLoaderManager); 108 }; 109 110 #endif // CHROME_BROWSER_INSTANT_INSTANT_LOADER_MANAGER_H_ 111
