michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef nsCategoryCache_h_
michael@0: #define nsCategoryCache_h_
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: 
michael@0: #include "nsICategoryManager.h"
michael@0: #include "nsIObserver.h"
michael@0: #include "nsISimpleEnumerator.h"
michael@0: #include "nsISupportsPrimitives.h"
michael@0: 
michael@0: #include "nsServiceManagerUtils.h"
michael@0: 
michael@0: #include "nsAutoPtr.h"
michael@0: #include "nsCOMArray.h"
michael@0: #include "nsInterfaceHashtable.h"
michael@0: 
michael@0: #include "nsXPCOM.h"
michael@0: 
michael@0: class NS_COM_GLUE nsCategoryObserver MOZ_FINAL : public nsIObserver
michael@0: {
michael@0:   public:
michael@0:     nsCategoryObserver(const char* aCategory);
michael@0:     ~nsCategoryObserver();
michael@0: 
michael@0:     void ListenerDied();
michael@0:     nsInterfaceHashtable<nsCStringHashKey, nsISupports>& GetHash()
michael@0:     {
michael@0:       return mHash;
michael@0:     }
michael@0: 
michael@0:     NS_DECL_ISUPPORTS
michael@0:     NS_DECL_NSIOBSERVER
michael@0:   private:
michael@0:     void RemoveObservers();
michael@0: 
michael@0:     nsInterfaceHashtable<nsCStringHashKey, nsISupports> mHash;
michael@0:     nsCString mCategory;
michael@0:     bool mObserversRemoved;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * This is a helper class that caches services that are registered in a certain
michael@0:  * category. The intended usage is that a service stores a variable of type
michael@0:  * nsCategoryCache<nsIFoo> in a member variable, where nsIFoo is the interface
michael@0:  * that these services should implement. The constructor of this class should
michael@0:  * then get the name of the category.
michael@0:  */
michael@0: template<class T>
michael@0: class nsCategoryCache MOZ_FINAL
michael@0: {
michael@0:   public:
michael@0:     explicit nsCategoryCache(const char* aCategory)
michael@0:       : mCategoryName(aCategory)
michael@0:     {
michael@0:     }
michael@0:     ~nsCategoryCache() {
michael@0:       if (mObserver)
michael@0: 	mObserver->ListenerDied();
michael@0:     }
michael@0: 
michael@0:     void GetEntries(nsCOMArray<T>& result) {
michael@0:       // Lazy initialization, so that services in this category can't
michael@0:       // cause reentrant getService (bug 386376)
michael@0:       if (!mObserver)
michael@0:         mObserver = new nsCategoryObserver(mCategoryName.get());
michael@0: 
michael@0:       mObserver->GetHash().EnumerateRead(EntriesToArray, &result);
michael@0:     }
michael@0: 
michael@0:   private:
michael@0:     // Not to be implemented
michael@0:     nsCategoryCache(const nsCategoryCache<T>&);
michael@0: 
michael@0:     static PLDHashOperator EntriesToArray(const nsACString& key,
michael@0: 					  nsISupports* entry, void* arg)
michael@0:     {
michael@0:       nsCOMArray<T>& entries = *static_cast<nsCOMArray<T>*>(arg);
michael@0: 
michael@0:       nsCOMPtr<T> service = do_QueryInterface(entry);
michael@0:       if (service) {
michael@0: 	entries.AppendObject(service);
michael@0:       }
michael@0:       return PL_DHASH_NEXT;
michael@0:     }
michael@0: 
michael@0:     nsCString mCategoryName;
michael@0:     nsRefPtr<nsCategoryObserver> mObserver;
michael@0: 
michael@0: };
michael@0: 
michael@0: #endif