gecko-dev/xpcom/threads/nsEventQueueService.cpp

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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** 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 Communicator client code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Rick Potts <rpotts@netscape.com>
* Ramiro Estrugo <ramiro@netscape.com>
* Warren Harris <warren@netscape.com>
* Leaf Nunes <leaf@mozilla.org>
* David Matiskella <davidm@netscape.com>
* David Hyatt <hyatt@netscape.com>
* Seth Spitzer <sspitzer@netscape.com>
* Suresh Duddi <dp@netscape.com>
* Bruce Mitchener <bruce@cybersight.com>
* Scott Collins <scc@netscape.com>
* Daniel Matejka <danm@netscape.com>
* Doug Turner <dougt@netscape.com>
* Stuart Parmenter <pavlov@netscape.com>
* Mike Kaply <mkaply@us.ibm.com>
* Dan Mosedale <dmose@mozilla.org>
*
* Alternatively, the contents of this file may be used under the terms of
* either of 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 ***** */
#include "nsEventQueueService.h"
#include "prmon.h"
#include "nsIComponentManager.h"
#include "nsIThread.h"
#include "nsPIEventQueueChain.h"
#include "prlog.h"
#if defined(PR_LOGGING) || defined(DEBUG_danm)
extern PRLogModuleInfo* gEventQueueLog;
extern PRUint32 gEventQueueLogCount;
#endif
static NS_DEFINE_CID(kEventQueueCID, NS_EVENTQUEUE_CID);
nsEventQueueServiceImpl::nsEventQueueServiceImpl()
{
mEventQMonitor = PR_NewMonitor();
#if defined(PR_LOGGING) && defined(DEBUG_danm)
if (!gEventQueueLog)
gEventQueueLog = PR_NewLogModule("nseventqueue");
#endif
}
PR_STATIC_CALLBACK(PLDHashOperator)
hash_enum_remove_queues(const void *aThread_ptr,
nsCOMPtr<nsIEventQueue>& aEldestQueue,
void* closure)
{
// 'aQueue' should be the eldest queue.
nsCOMPtr<nsPIEventQueueChain> pie(do_QueryInterface(aEldestQueue));
nsCOMPtr<nsIEventQueue> q;
// stop accepting events for youngest to oldest
pie->GetYoungest(getter_AddRefs(q));
while (q) {
q->StopAcceptingEvents();
nsCOMPtr<nsPIEventQueueChain> pq(do_QueryInterface(q));
pq->GetElder(getter_AddRefs(q));
}
return PL_DHASH_REMOVE;
}
nsEventQueueServiceImpl::~nsEventQueueServiceImpl()
{
// XXX make it so we only enum over this once
mEventQTable.Enumerate(hash_enum_remove_queues, nsnull); // call StopAcceptingEvents on everything and clear out the hashtable
PR_DestroyMonitor(mEventQMonitor);
}
nsresult
nsEventQueueServiceImpl::Init()
{
NS_ENSURE_TRUE(mEventQMonitor, NS_ERROR_OUT_OF_MEMORY);
// This will only be called once on the main thread, so it's safe to
// not enter the monitor here.
if (!mEventQTable.Init()) {
return NS_ERROR_OUT_OF_MEMORY;
}
// ensure that a main thread event queue exists!
nsresult rv;
nsCOMPtr<nsIThread> mainThread;
rv = nsIThread::GetMainThread(getter_AddRefs(mainThread));
if (NS_SUCCEEDED(rv)) {
PRThread *thr;
rv = mainThread->GetPRThread(&thr);
if (NS_SUCCEEDED(rv))
rv = CreateEventQueue(thr, PR_TRUE);
}
return rv;
}
/* nsISupports interface implementation... */
NS_IMPL_THREADSAFE_ISUPPORTS1(nsEventQueueServiceImpl, nsIEventQueueService)
/* nsIEventQueueService interface implementation... */
NS_IMETHODIMP
nsEventQueueServiceImpl::CreateThreadEventQueue()
{
return CreateEventQueue(PR_GetCurrentThread(), PR_TRUE);
}
NS_IMETHODIMP
nsEventQueueServiceImpl::CreateMonitoredThreadEventQueue()
{
return CreateEventQueue(PR_GetCurrentThread(), PR_FALSE);
}
NS_IMETHODIMP
nsEventQueueServiceImpl::CreateFromIThread(nsIThread *aThread, PRBool aNative,
nsIEventQueue **aResult)
{
nsresult rv;
PRThread *prThread;
rv = aThread->GetPRThread(&prThread);
if (NS_SUCCEEDED(rv)) {
rv = CreateEventQueue(prThread, aNative); // addrefs
if (NS_SUCCEEDED(rv))
rv = GetThreadEventQueue(prThread, aResult); // addrefs
}
return rv;
}
// private method
NS_IMETHODIMP
nsEventQueueServiceImpl::MakeNewQueue(PRThread* thread,
PRBool aNative,
nsIEventQueue **aQueue)
{
nsresult rv;
nsCOMPtr<nsIEventQueue> queue = do_CreateInstance(kEventQueueCID, &rv);
if (NS_SUCCEEDED(rv)) {
rv = queue->InitFromPRThread(thread, aNative);
}
*aQueue = queue;
NS_IF_ADDREF(*aQueue);
return rv;
}
// private method
NS_IMETHODIMP
nsEventQueueServiceImpl::CreateEventQueue(PRThread *aThread, PRBool aNative)
{
nsresult rv = NS_OK;
/* Enter the lock that protects the EventQ hashtable... */
PR_EnterMonitor(mEventQMonitor);
/* create only one event queue chain per thread... */
if (!mEventQTable.GetWeak(aThread)) {
nsCOMPtr<nsIEventQueue> queue;
// we don't have one in the table
rv = MakeNewQueue(aThread, aNative, getter_AddRefs(queue)); // create new queue
mEventQTable.Put(aThread, queue); // add to the table (initial addref)
}
// Release the EventQ lock...
PR_ExitMonitor(mEventQMonitor);
return rv;
}
NS_IMETHODIMP
nsEventQueueServiceImpl::DestroyThreadEventQueue(void)
{
nsresult rv = NS_OK;
/* Enter the lock that protects the EventQ hashtable... */
PR_EnterMonitor(mEventQMonitor);
PRThread* currentThread = PR_GetCurrentThread();
nsIEventQueue* queue = mEventQTable.GetWeak(currentThread);
if (queue) {
queue->StopAcceptingEvents(); // tell the queue to stop accepting events
queue = nsnull; // Queue may die on the next line
mEventQTable.Remove(currentThread); // remove nsIEventQueue from hash table (releases)
}
// Release the EventQ lock...
PR_ExitMonitor(mEventQMonitor);
return rv;
}
NS_IMETHODIMP
nsEventQueueServiceImpl::CreateFromPLEventQueue(PLEventQueue* aPLEventQueue, nsIEventQueue** aResult)
{
// Create our thread queue using the component manager
nsresult rv;
nsCOMPtr<nsIEventQueue> queue = do_CreateInstance(kEventQueueCID, &rv);
if (NS_FAILED(rv)) return rv;
rv = queue->InitFromPLQueue(aPLEventQueue);
if (NS_FAILED(rv)) return rv;
*aResult = queue;
NS_IF_ADDREF(*aResult);
return NS_OK;
}
// Return the active event queue on our chain
/* inline */
nsresult nsEventQueueServiceImpl::GetYoungestEventQueue(nsIEventQueue *queue, nsIEventQueue **aResult)
{
nsCOMPtr<nsIEventQueue> answer;
if (queue) {
nsCOMPtr<nsPIEventQueueChain> ourChain(do_QueryInterface(queue));
if (ourChain)
ourChain->GetYoungestActive(getter_AddRefs(answer));
else
answer = queue;
}
*aResult = answer;
NS_IF_ADDREF(*aResult);
return NS_OK;
}
// create new event queue, append it to the current thread's chain of event queues.
// return it, addrefed.
NS_IMETHODIMP
nsEventQueueServiceImpl::PushThreadEventQueue(nsIEventQueue **aNewQueue)
{
nsresult rv = NS_OK;
PRThread* currentThread = PR_GetCurrentThread();
PRBool native = PR_TRUE; // native by default as per old comment
NS_ASSERTION(aNewQueue, "PushThreadEventQueue called with null param");
/* Enter the lock that protects the EventQ hashtable... */
PR_EnterMonitor(mEventQMonitor);
nsIEventQueue* queue = mEventQTable.GetWeak(currentThread);
NS_ASSERTION(queue, "pushed event queue on top of nothing");
if (queue) { // find out what kind of queue our relatives are
nsCOMPtr<nsIEventQueue> youngQueue;
GetYoungestEventQueue(queue, getter_AddRefs(youngQueue));
if (youngQueue) {
youngQueue->IsQueueNative(&native);
}
}
nsIEventQueue* newQueue = nsnull;
MakeNewQueue(currentThread, native, &newQueue); // create new queue; addrefs
if (!queue) {
// shouldn't happen. as a fallback, we guess you wanted a native queue
mEventQTable.Put(currentThread, newQueue);
}
// append to the event queue chain
nsCOMPtr<nsPIEventQueueChain> ourChain(do_QueryInterface(queue)); // QI the queue in the hash table
if (ourChain)
ourChain->AppendQueue(newQueue); // append new queue to it
*aNewQueue = newQueue;
#if defined(PR_LOGGING) && defined(DEBUG_danm)
PLEventQueue *equeue;
(*aNewQueue)->GetPLEventQueue(&equeue);
PR_LOG(gEventQueueLog, PR_LOG_DEBUG,
("EventQueue: Service push queue [queue=%lx]",(long)equeue));
++gEventQueueLogCount;
#endif
// Release the EventQ lock...
PR_ExitMonitor(mEventQMonitor);
return rv;
}
// disable and release the given queue (though the last one won't be released)
NS_IMETHODIMP
nsEventQueueServiceImpl::PopThreadEventQueue(nsIEventQueue *aQueue)
{
PRThread* currentThread = PR_GetCurrentThread();
/* Enter the lock that protects the EventQ hashtable... */
PR_EnterMonitor(mEventQMonitor);
nsCOMPtr<nsIEventQueue> eldestQueue;
mEventQTable.Get(currentThread, getter_AddRefs(eldestQueue));
// If we are popping the eldest queue, remove its mEventQTable entry.
if (aQueue == eldestQueue)
mEventQTable.Remove(currentThread);
// Exit the monitor before processing pending events to avoid deadlock.
// Our reference from the eldestQueue nsCOMPtr will keep that object alive.
// Since it is thread-private, no one else can race with us here.
PR_ExitMonitor(mEventQMonitor);
if (!eldestQueue)
return NS_ERROR_FAILURE;
#if defined(PR_LOGGING) && defined(DEBUG_danm)
PLEventQueue *equeue;
aQueue->GetPLEventQueue(&equeue);
PR_LOG(gEventQueueLog, PR_LOG_DEBUG,
("EventQueue: Service pop queue [queue=%lx]",(long)equeue));
++gEventQueueLogCount;
#endif
aQueue->StopAcceptingEvents();
aQueue->ProcessPendingEvents(); // make sure we don't orphan any events
return NS_OK;
}
NS_IMETHODIMP
nsEventQueueServiceImpl::GetThreadEventQueue(PRThread* aThread, nsIEventQueue** aResult)
{
/* Parameter validation... */
if (NULL == aResult) return NS_ERROR_NULL_POINTER;
PRThread* keyThread = aThread;
if (keyThread == NS_CURRENT_THREAD)
{
keyThread = PR_GetCurrentThread();
}
else if (keyThread == NS_UI_THREAD)
{
nsCOMPtr<nsIThread> mainIThread;
// Get the primordial thread
nsresult rv = nsIThread::GetMainThread(getter_AddRefs(mainIThread));
if (NS_FAILED(rv)) return rv;
rv = mainIThread->GetPRThread(&keyThread);
if (NS_FAILED(rv)) return rv;
}
/* Enter the lock that protects the EventQ hashtable... */
PR_EnterMonitor(mEventQMonitor);
nsCOMPtr<nsIEventQueue> queue;
mEventQTable.Get(keyThread, getter_AddRefs(queue));
PR_ExitMonitor(mEventQMonitor);
if (queue) {
GetYoungestEventQueue(queue, aResult); // get the youngest active queue
} else {
*aResult = nsnull;
}
// XXX: Need error code for requesting an event queue when none exists...
if (!*aResult) {
return NS_ERROR_NOT_AVAILABLE;
}
return NS_OK;
}
NS_IMETHODIMP
nsEventQueueServiceImpl::ResolveEventQueue(nsIEventQueue* queueOrConstant, nsIEventQueue* *resultQueue)
{
if (queueOrConstant == NS_CURRENT_EVENTQ) {
return GetThreadEventQueue(NS_CURRENT_THREAD, resultQueue);
}
else if (queueOrConstant == NS_UI_THREAD_EVENTQ) {
return GetThreadEventQueue(NS_UI_THREAD, resultQueue);
}
*resultQueue = queueOrConstant;
NS_ADDREF(*resultQueue);
return NS_OK;
}
NS_IMETHODIMP
nsEventQueueServiceImpl::GetSpecialEventQueue(PRInt32 aQueue,
nsIEventQueue* *_retval)
{
nsresult rv;
// barf if someone gave us a zero pointer
//
if (!_retval) {
return NS_ERROR_NULL_POINTER;
}
// try and get the requested event queue, returning NS_ERROR_FAILURE if there
// is a problem. GetThreadEventQueue() does the AddRef() for us.
//
switch (aQueue) {
case CURRENT_THREAD_EVENT_QUEUE:
rv = GetThreadEventQueue(NS_CURRENT_THREAD, _retval);
if (NS_FAILED(rv)) {
return NS_ERROR_FAILURE;
}
break;
case UI_THREAD_EVENT_QUEUE:
rv = GetThreadEventQueue(NS_UI_THREAD, _retval);
if (NS_FAILED(rv)) {
return NS_ERROR_FAILURE;
}
break;
// somebody handed us a bogus constant
//
default:
return NS_ERROR_ILLEGAL_VALUE;
}
return NS_OK;
}