content/media/SharedThreadPool.h@44a2da4a2ab2 (annotated)
content/media/SharedThreadPool.h
Fri, 16 Jan 2015 04:50:19 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Fri, 16 Jan 2015 04:50:19 +0100
- branch
- TOR_BUG_9701
- changeset 13
- 44a2da4a2ab2
- permissions
- -rw-r--r--
Replace accessor implementation with direct member state manipulation, by
request https://trac.torproject.org/projects/tor/ticket/9701#comment:32
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* vim:set ts=2 sw=2 sts=2 et cindent: */ |
| michael@0 | 3 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | #ifndef SharedThreadPool_h_ |
| michael@0 | 8 | #define SharedThreadPool_h_ |
| michael@0 | 9 | |
| michael@0 | 10 | #include <queue> |
| michael@0 | 11 | #include "mozilla/RefPtr.h" |
| michael@0 | 12 | #include "nsThreadUtils.h" |
| michael@0 | 13 | #include "nsIThreadPool.h" |
| michael@0 | 14 | #include "nsISupports.h" |
| michael@0 | 15 | #include "nsISupportsImpl.h" |
| michael@0 | 16 | #include "nsCOMPtr.h" |
| michael@0 | 17 | |
| michael@0 | 18 | namespace mozilla { |
| michael@0 | 19 | |
| michael@0 | 20 | // Wrapper that makes an nsIThreadPool a singleton, and provides a |
| michael@0 | 21 | // consistent threadsafe interface to get instances. Callers simply get a |
| michael@0 | 22 | // SharedThreadPool by the name of its nsIThreadPool. All get requests of |
| michael@0 | 23 | // the same name get the same SharedThreadPool. Users must store a reference |
| michael@0 | 24 | // to the pool, and when the last reference to a SharedThreadPool is dropped |
| michael@0 | 25 | // the pool is shutdown and deleted. Users aren't required to manually |
| michael@0 | 26 | // shutdown the pool, and can release references on any thread. On Windows |
| michael@0 | 27 | // all threads in the pool have MSCOM initialized with COINIT_MULTITHREADED. |
| michael@0 | 28 | class SharedThreadPool : public nsIThreadPool |
| michael@0 | 29 | { |
| michael@0 | 30 | public: |
| michael@0 | 31 | |
| michael@0 | 32 | // Gets (possibly creating) the shared thread pool singleton instance with |
| michael@0 | 33 | // thread pool named aName. |
| michael@0 | 34 | // *Must* be called on the main thread. |
| michael@0 | 35 | static TemporaryRef<SharedThreadPool> Get(const nsCString& aName, |
| michael@0 | 36 | uint32_t aThreadLimit = 4); |
| michael@0 | 37 | |
| michael@0 | 38 | // Spins the event loop until all thread pools are shutdown. |
| michael@0 | 39 | // *Must* be called on the main thread. |
| michael@0 | 40 | static void SpinUntilShutdown(); |
| michael@0 | 41 | |
| michael@0 | 42 | // We implement custom threadsafe AddRef/Release pair, that destroys the |
| michael@0 | 43 | // the shared pool singleton when the refcount drops to 0. The addref/release |
| michael@0 | 44 | // are implemented using locking, so it's not recommended that you use them |
| michael@0 | 45 | // in a tight loop. |
| michael@0 | 46 | NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr); |
| michael@0 | 47 | NS_IMETHOD_(MozExternalRefCountType) AddRef(void); |
| michael@0 | 48 | NS_IMETHOD_(MozExternalRefCountType) Release(void); |
| michael@0 | 49 | |
| michael@0 | 50 | // Forward behaviour to wrapped thread pool implementation. |
| michael@0 | 51 | NS_FORWARD_SAFE_NSITHREADPOOL(mPool); |
| michael@0 | 52 | NS_FORWARD_SAFE_NSIEVENTTARGET(GetEventTarget()); |
| michael@0 | 53 | |
| michael@0 | 54 | nsIEventTarget* GetEventTarget() { |
| michael@0 | 55 | return mEventTarget; |
| michael@0 | 56 | } |
| michael@0 | 57 | |
| michael@0 | 58 | private: |
| michael@0 | 59 | |
| michael@0 | 60 | // Creates necessary statics. |
| michael@0 | 61 | // Main thread only. |
| michael@0 | 62 | static void EnsureInitialized(); |
| michael@0 | 63 | |
| michael@0 | 64 | // Creates a singleton SharedThreadPool wrapper around aPool. |
| michael@0 | 65 | // aName is the name of the aPool, and is used to lookup the |
| michael@0 | 66 | // SharedThreadPool in the hash table of all created pools. |
| michael@0 | 67 | SharedThreadPool(const nsCString& aName, |
| michael@0 | 68 | nsIThreadPool* aPool); |
| michael@0 | 69 | virtual ~SharedThreadPool(); |
| michael@0 | 70 | |
| michael@0 | 71 | nsresult EnsureThreadLimitIsAtLeast(uint32_t aThreadLimit); |
| michael@0 | 72 | |
| michael@0 | 73 | // Name of mPool. |
| michael@0 | 74 | const nsCString mName; |
| michael@0 | 75 | |
| michael@0 | 76 | // Thread pool being wrapped. |
| michael@0 | 77 | nsCOMPtr<nsIThreadPool> mPool; |
| michael@0 | 78 | |
| michael@0 | 79 | // Refcount. We implement custom ref counting so that the thread pool is |
| michael@0 | 80 | // shutdown in a threadsafe manner and singletonness is preserved. |
| michael@0 | 81 | nsrefcnt mRefCnt; |
| michael@0 | 82 | |
| michael@0 | 83 | // mPool QI'd to nsIEventTarget. We cache this, so that we can use |
| michael@0 | 84 | // NS_FORWARD_SAFE_NSIEVENTTARGET above. |
| michael@0 | 85 | nsCOMPtr<nsIEventTarget> mEventTarget; |
| michael@0 | 86 | }; |
| michael@0 | 87 | |
| michael@0 | 88 | } // namespace mozilla |
| michael@0 | 89 | |
| michael@0 | 90 | #endif // SharedThreadPool_h_ |
