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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef nsCategoryCache_h_
#define nsCategoryCache_h_
#include "mozilla/Attributes.h"
#include "nsICategoryManager.h"
#include "nsIObserver.h"
#include "nsISimpleEnumerator.h"
#include "nsISupportsPrimitives.h"
#include "nsServiceManagerUtils.h"
#include "nsAutoPtr.h"
#include "nsCOMArray.h"
#include "nsDataHashtable.h"
#include "nsXPCOM.h"
class NS_NO_VTABLE nsCategoryListener {
protected:
// no virtual destructor (people shouldn't delete through an
// nsCategoryListener pointer)
~nsCategoryListener() {}
public:
virtual void EntryAdded(const nsCString& aValue) = 0;
virtual void EntryRemoved(const nsCString& aValue) = 0;
virtual void CategoryCleared() = 0;
};
class NS_COM_GLUE nsCategoryObserver MOZ_FINAL : public nsIObserver {
public:
nsCategoryObserver(const char* aCategory,
nsCategoryListener* aCategoryListener);
~nsCategoryObserver();
void ListenerDied();
NS_DECL_ISUPPORTS
NS_DECL_NSIOBSERVER
private:
NS_HIDDEN_(void) RemoveObservers();
nsDataHashtable<nsCStringHashKey, nsCString> mHash;
nsCategoryListener* mListener;
nsCString mCategory;
bool mObserversRemoved;
};
/**
* This is a helper class that caches services that are registered in a certain
* category. The intended usage is that a service stores a variable of type
* nsCategoryCache<nsIFoo> in a member variable, where nsIFoo is the interface
* that these services should implement. The constructor of this class should
* then get the name of the category.
*/
template<class T>
class nsCategoryCache : protected nsCategoryListener {
public:
explicit nsCategoryCache(const char* aCategory);
~nsCategoryCache() { if (mObserver) mObserver->ListenerDied(); }
const nsCOMArray<T>& GetEntries() {
// Lazy initialization, so that services in this category can't
// cause reentrant getService (bug 386376)
if (!mObserver)
mObserver = new nsCategoryObserver(mCategoryName.get(), this);
return mEntries;
}
protected:
virtual void EntryAdded(const nsCString& aValue);
virtual void EntryRemoved(const nsCString& aValue);
virtual void CategoryCleared();
private:
friend class CategoryObserver;
// Not to be implemented
nsCategoryCache(const nsCategoryCache<T>&);
nsCString mCategoryName;
nsCOMArray<T> mEntries;
nsRefPtr<nsCategoryObserver> mObserver;
};
// -----------------------------------
// Implementation
template<class T>
nsCategoryCache<T>::nsCategoryCache(const char* aCategory)
: mCategoryName(aCategory)
{
}
template<class T>
void nsCategoryCache<T>::EntryAdded(const nsCString& aValue) {
nsCOMPtr<T> catEntry = do_GetService(aValue.get());
if (catEntry)
mEntries.AppendObject(catEntry);
}
template<class T>
void nsCategoryCache<T>::EntryRemoved(const nsCString& aValue) {
nsCOMPtr<T> catEntry = do_GetService(aValue.get());
if (catEntry)
mEntries.RemoveObject(catEntry);
}
template<class T>
void nsCategoryCache<T>::CategoryCleared() {
mEntries.Clear();
}
#endif
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