gecko-dev/xpcom/threads/nsThread.h

194 lines
5.6 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is Mozilla code.
*
* The Initial Developer of the Original Code is Google Inc.
* Portions created by the Initial Developer are Copyright (C) 2006
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Darin Fisher <darin@meer.net>
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
#ifndef nsThread_h__
#define nsThread_h__
#include "mozilla/Mutex.h"
#include "nsIThreadInternal.h"
#include "nsISupportsPriority.h"
#include "nsEventQueue.h"
#include "nsThreadUtils.h"
#include "nsString.h"
#include "nsTObserverArray.h"
// A native thread
class nsThread : public nsIThreadInternal, public nsISupportsPriority
{
public:
NS_DECL_ISUPPORTS
NS_DECL_NSIEVENTTARGET
NS_DECL_NSITHREAD
NS_DECL_NSITHREADINTERNAL
NS_DECL_NSISUPPORTSPRIORITY
enum MainThreadFlag {
MAIN_THREAD,
NOT_MAIN_THREAD
};
nsThread(MainThreadFlag aMainThread, PRUint32 aStackSize);
// Initialize this as a wrapper for a new PRThread.
nsresult Init();
// Initialize this as a wrapper for the current PRThread.
nsresult InitCurrentThread();
// The PRThread corresponding to this thread.
PRThread *GetPRThread() { return mThread; }
// If this flag is true, then the nsThread was created using
// nsIThreadManager::NewThread.
bool ShutdownRequired() { return mShutdownRequired; }
// Clear the observer list.
void ClearObservers() { mEventObservers.Clear(); }
private:
friend class nsThreadShutdownEvent;
~nsThread();
bool ShuttingDown() { return mShutdownContext != nsnull; }
static void ThreadFunc(void *arg);
// Helper
already_AddRefed<nsIThreadObserver> GetObserver() {
nsIThreadObserver *obs;
nsThread::GetObserver(&obs);
return already_AddRefed<nsIThreadObserver>(obs);
}
// Wrappers for event queue methods:
bool GetEvent(bool mayWait, nsIRunnable **event) {
return mEvents->GetEvent(mayWait, event);
}
nsresult PutEvent(nsIRunnable *event);
// Wrapper for nsEventQueue that supports chaining.
class nsChainedEventQueue {
public:
nsChainedEventQueue(nsIThreadEventFilter *filter = nsnull)
: mNext(nsnull), mFilter(filter) {
}
bool GetEvent(bool mayWait, nsIRunnable **event) {
return mQueue.GetEvent(mayWait, event);
}
bool PutEvent(nsIRunnable *event);
bool HasPendingEvent() {
return mQueue.HasPendingEvent();
}
class nsChainedEventQueue *mNext;
private:
nsCOMPtr<nsIThreadEventFilter> mFilter;
nsEventQueue mQueue;
};
// This lock protects access to mObserver, mEvents and mEventsAreDoomed.
// All of those fields are only modified on the thread itself (never from
// another thread). This means that we can avoid holding the lock while
// using mObserver and mEvents on the thread itself. When calling PutEvent
// on mEvents, we have to hold the lock to synchronize with PopEventQueue.
mozilla::Mutex mLock;
nsCOMPtr<nsIThreadObserver> mObserver;
// Only accessed on the target thread.
nsAutoTObserverArray<nsCOMPtr<nsIThreadObserver>, 2> mEventObservers;
nsChainedEventQueue *mEvents; // never null
nsChainedEventQueue mEventsRoot;
PRInt32 mPriority;
PRThread *mThread;
PRUint32 mRunningEvent; // counter
PRUint32 mStackSize;
struct nsThreadShutdownContext *mShutdownContext;
bool mShutdownRequired;
bool mShutdownPending;
// Set to true when events posted to this thread will never run.
bool mEventsAreDoomed;
MainThreadFlag mIsMainThread;
};
//-----------------------------------------------------------------------------
class nsThreadSyncDispatch : public nsRunnable {
public:
nsThreadSyncDispatch(nsIThread *origin, nsIRunnable *task)
: mOrigin(origin), mSyncTask(task), mResult(NS_ERROR_NOT_INITIALIZED) {
}
bool IsPending() {
return mSyncTask != nsnull;
}
nsresult Result() {
return mResult;
}
private:
NS_DECL_NSIRUNNABLE
nsCOMPtr<nsIThread> mOrigin;
nsCOMPtr<nsIRunnable> mSyncTask;
nsresult mResult;
};
namespace mozilla {
/**
* This function causes the main thread to fire a memory pressure event at its
* next available opportunity.
*
* You may call this function from any thread.
*/
void ScheduleMemoryPressureEvent();
} // namespace mozilla
#endif // nsThread_h__