AppCacheHost cache selection algorithm

webkit/appcache/appcache_host.h

Index: webkit/appcache/appcache_host.h
===================================================================
--- webkit/appcache/appcache_host.h	(revision 26254)
+++ webkit/appcache/appcache_host.h	(working copy)
@@ -6,42 +6,126 @@
 #define WEBKIT_APPCACHE_APPCACHE_HOST_H_
 
 #include "base/ref_counted.h"
+#include "base/task.h"
+#include "base/weak_ptr.h"
+#include "googleurl/src/gurl.h"
+#include "testing/gtest/include/gtest/gtest_prod.h"
+#include "webkit/appcache/appcache.h"
+#include "webkit/appcache/appcache_interfaces.h"
+#include "webkit/appcache/appcache_service.h"
 
+class URLRequest;
+
 namespace appcache {
 
 class AppCache;
 class AppCacheFrontend;
 class AppCacheGroup;
+class AppCacheRequestHandler;
 
+typedef Callback2<Status, void*>::Type GetStatusCallback;
+typedef Callback2<bool, void*>::Type StartUpdateCallback;
+typedef Callback2<bool, void*>::Type SwapCacheCallback;
+
 // Server-side representation of an application cache host.
-class AppCacheHost {
+class AppCacheHost : public base::SupportsWeakPtr<AppCacheHost>,
+                     public AppCacheService::LoadClient {
  public:
-  AppCacheHost(int host_id, AppCacheFrontend* frontend);
+  AppCacheHost(int host_id, AppCacheFrontend* frontend,
+               AppCacheService* service);
   ~AppCacheHost();
 
-  int host_id() { return host_id_; }
-  AppCacheFrontend* frontend() { return frontend_; }
+  // Support for cache selection and scriptable method calls.
+  void SelectCache(const GURL& document_url,
+                   const int64 cache_document_was_loaded_from,
+                   const GURL& manifest_url);
+  void MarkAsForeignEntry(const GURL& document_url,
+                          int64 cache_document_was_loaded_from);
+  void GetStatusWithCallback(GetStatusCallback* callback,
+                             void* callback_param);
+  void StartUpdateWithCallback(StartUpdateCallback* callback,
+                               void* callback_param);
+  void SwapCacheWithCallback(SwapCacheCallback* callback,
+                             void* callback_param);
 
-  AppCache* selected_cache() { return selected_cache_; }
-  void set_selected_cache(AppCache* cache);
+  // Support for loading resources out of the appcache.
+  // Returns NULL if the host is not associated with a complete cache.
+  AppCacheRequestHandler* CreateRequestHandler(URLRequest* request,
+                                               bool is_main_request);
 
-  bool is_selection_pending() {
-    return false;  // TODO(michaeln)
+  // Establishes an association between this host and a cache. 'cache' may be
+  // NULL to break any existing association. Associations are established
+  // either thru the cache selection algorithm implemented (in this class),
+  // or by the update algorithm (see AppCacheUpdateJob).
+  void AssociateCache(AppCache* cache);
+
+  int host_id() const { return host_id_; }
+  AppCacheService* service() const { return service_; }
+  AppCacheFrontend* frontend() const { return frontend_; }
+  AppCache* associated_cache() const { return associated_cache_.get(); }
+
+ private:
+  bool is_selection_pending() const {
+    return pending_selected_cache_id_ != kNoCacheId ||
+           !pending_selected_manifest_url_.is_empty();
   }
+  Status GetStatus();
+  void LoadCache(int64 cache_id);
+  void LoadOrCreateGroup(const GURL& manifest_url);
 
- private:
-  // identifies the corresponding appcache host in the child process
+  // LoadClient impl
+  virtual void CacheLoadedCallback(AppCache* cache, int64 cache_id);
+  virtual void GroupLoadedCallback(AppCacheGroup* group,
+                                   const GURL& manifest_url);
+
+  void FinishCacheSelection(AppCache* cache, AppCacheGroup* group);
+  void DoPendingGetStatus();
+  void DoPendingStartUpdate();
+  void DoPendingSwapCache();
+
+  // Identifies the corresponding appcache host in the child process.
   int host_id_;
 
-  // application cache associated with this host, if any
-  scoped_refptr<AppCache> selected_cache_;
+  // The cache associated with this host, if any.
+  scoped_refptr<AppCache> associated_cache_;
 
-  // The reference to the appcache group ensures the group exists as long
-  // as there is a host using a cache belonging to that group.
+  // The reference to the group ensures the group exists
+  // while we have an association with a cache in the group.
   scoped_refptr<AppCacheGroup> group_;
 
-  // frontend to deliver notifications about this host to child process
+  // Cache loading is async, if we're loading a specific cache or group
+  // for the purposes of cache selection, one or the other of these will
+  // indicate which cache or group is being loaded.
+  int64 pending_selected_cache_id_;
+  GURL pending_selected_manifest_url_;
+
+  // A new master entry to be added to the cache, may be empty.
+  GURL new_master_entry_url_;
+
+  // The frontend proxy to deliver notifications to the child process.
   AppCacheFrontend* frontend_;
+
+  // Our central service object.
+  AppCacheService* service_;
+
+  // Since these are synchronous scriptable api calls in the client,
+  // there can only be one type of callback pending.
+  // Also, we have to wait until we have a cache selection prior
+  // to responding to these calls, as cache selection involves
+  // async loading of a cache or a group from storage.
+  GetStatusCallback* pending_get_status_callback_;
+  StartUpdateCallback* pending_start_update_callback_;
+  SwapCacheCallback* pending_swap_cache_callback_;
+  void* pending_callback_param_;
+
+  FRIEND_TEST(AppCacheTest, CleanupUnusedCache);
+  FRIEND_TEST(AppCacheGroupTest, CleanupUnusedGroup);
+  FRIEND_TEST(AppCacheHostTest, Basic);
+  FRIEND_TEST(AppCacheHostTest, SelectNoCache);
+  FRIEND_TEST(AppCacheHostTest, ForeignEntry);
+  FRIEND_TEST(AppCacheHostTest, FailedCacheLoad);
+  FRIEND_TEST(AppCacheHostTest, FailedGroupLoad);
+  DISALLOW_COPY_AND_ASSIGN(AppCacheHost);
 };
 
 }  // namespace appcache