1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/nsCategoryCache.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,95 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.6 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#ifndef nsCategoryCache_h_
1.9 +#define nsCategoryCache_h_
1.10 +
1.11 +#include "mozilla/Attributes.h"
1.12 +
1.13 +#include "nsICategoryManager.h"
1.14 +#include "nsIObserver.h"
1.15 +#include "nsISimpleEnumerator.h"
1.16 +#include "nsISupportsPrimitives.h"
1.17 +
1.18 +#include "nsServiceManagerUtils.h"
1.19 +
1.20 +#include "nsAutoPtr.h"
1.21 +#include "nsCOMArray.h"
1.22 +#include "nsInterfaceHashtable.h"
1.23 +
1.24 +#include "nsXPCOM.h"
1.25 +
1.26 +class NS_COM_GLUE nsCategoryObserver MOZ_FINAL : public nsIObserver
1.27 +{
1.28 + public:
1.29 + nsCategoryObserver(const char* aCategory);
1.30 + ~nsCategoryObserver();
1.31 +
1.32 + void ListenerDied();
1.33 + nsInterfaceHashtable<nsCStringHashKey, nsISupports>& GetHash()
1.34 + {
1.35 + return mHash;
1.36 + }
1.37 +
1.38 + NS_DECL_ISUPPORTS
1.39 + NS_DECL_NSIOBSERVER
1.40 + private:
1.41 + void RemoveObservers();
1.42 +
1.43 + nsInterfaceHashtable<nsCStringHashKey, nsISupports> mHash;
1.44 + nsCString mCategory;
1.45 + bool mObserversRemoved;
1.46 +};
1.47 +
1.48 +/**
1.49 + * This is a helper class that caches services that are registered in a certain
1.50 + * category. The intended usage is that a service stores a variable of type
1.51 + * nsCategoryCache<nsIFoo> in a member variable, where nsIFoo is the interface
1.52 + * that these services should implement. The constructor of this class should
1.53 + * then get the name of the category.
1.54 + */
1.55 +template<class T>
1.56 +class nsCategoryCache MOZ_FINAL
1.57 +{
1.58 + public:
1.59 + explicit nsCategoryCache(const char* aCategory)
1.60 + : mCategoryName(aCategory)
1.61 + {
1.62 + }
1.63 + ~nsCategoryCache() {
1.64 + if (mObserver)
1.65 + mObserver->ListenerDied();
1.66 + }
1.67 +
1.68 + void GetEntries(nsCOMArray<T>& result) {
1.69 + // Lazy initialization, so that services in this category can't
1.70 + // cause reentrant getService (bug 386376)
1.71 + if (!mObserver)
1.72 + mObserver = new nsCategoryObserver(mCategoryName.get());
1.73 +
1.74 + mObserver->GetHash().EnumerateRead(EntriesToArray, &result);
1.75 + }
1.76 +
1.77 + private:
1.78 + // Not to be implemented
1.79 + nsCategoryCache(const nsCategoryCache<T>&);
1.80 +
1.81 + static PLDHashOperator EntriesToArray(const nsACString& key,
1.82 + nsISupports* entry, void* arg)
1.83 + {
1.84 + nsCOMArray<T>& entries = *static_cast<nsCOMArray<T>*>(arg);
1.85 +
1.86 + nsCOMPtr<T> service = do_QueryInterface(entry);
1.87 + if (service) {
1.88 + entries.AppendObject(service);
1.89 + }
1.90 + return PL_DHASH_NEXT;
1.91 + }
1.92 +
1.93 + nsCString mCategoryName;
1.94 + nsRefPtr<nsCategoryObserver> mObserver;
1.95 +
1.96 +};
1.97 +
1.98 +#endif
