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* replaced use of semaphores in Unix version of TThread for suspend/resume

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functionality with RTLEvent:
   o the thread manager semaphore functionality isn't used for anything else,
     and the main difference between mutex/condvar and semaphores is that the
     latter can be used for IPC (while the thread manager is always used
     within a single process) and that they are counting (but since a thread
     can only suspend itself nowadays, it cannot be suspended recursively)
   o OS X sandboxing does not support the use of semaphores (or rather: Apple
     does not allow sandboxing rules that enable the use of IPC semaphores in
     the appstore)

git-svn-id: trunk@28965 -
This commit is contained in:
Jonas Maebe 2014-11-02 15:00:24 +00:00
parent 35a313d98c
commit 77c1364713
2 changed files with 14 additions and 16 deletions
rtl
objpas/classes
classesh.inc
unix
tthread.inc

2
rtl/objpas/classes/classesh.inc
View File

@ -1609,7 +1609,7 @@ type
{$ifdef Unix}
private
// see tthread.inc, ThreadFunc and TThread.Resume
FSem: Pointer;
FSuspendEvent: PRTLEvent;
FInitialSuspended: boolean;
FSuspendedInternal: longbool;
FThreadReaped: boolean;

28
rtl/unix/tthread.inc
View File

@ -29,9 +29,9 @@
control. Therefore, I didn't implement .Suspend() if its called from
outside the threads execution flow (except on Linux _without_ NPTL).
The implementation for .suspend uses a semaphore, which is initialized
The implementation for .suspend uses an RTLEvent, which is initialized
at thread creation. If the thread tries to suspend itself, we simply
let it wait on the semaphore until it is unblocked by someone else
let it wait on the Event until it is unblocked by someone else
who calls .Resume.
@ -82,8 +82,8 @@ begin
WRITE_DEBUG('AfterConstruction should have been called for ',ptruint(lthread));
if LThread.FInitialSuspended then
begin
WRITE_DEBUG('thread ', ptruint(LThread), ' waiting for semaphore ', ptruint(LThread.FSem));
SemaphoreWait(LThread.FSem);
WRITE_DEBUG('thread ', ptruint(LThread), ' waiting for RTLEvent ', ptruint(LThread.FSuspendEvent));
RtlEventWaitFor(LThread.FSuspendEvent);
if not(LThread.FTerminated) then
begin
if not LThread.FSuspended then
@ -103,7 +103,7 @@ begin
begin
LThread.FSuspendedInternal := true;
WRITE_DEBUG('waiting for SuspendedInternal - ', LThread.ClassName);
SemaphoreWait(LThread.FSem);
RtlEventWaitFor(LThread.FSuspendEvent);
CurrentThreadVar := LThread;
WRITE_DEBUG('going into LThread.Execute - ', LThread.ClassName);
LThread.Execute;
@ -148,10 +148,8 @@ end;
procedure TThread.SysCreate(CreateSuspended: Boolean;
const StackSize: SizeUInt);
begin
FSem := SemaphoreInit();
if FSem = pointer(-1) then
raise EThread.create('Semaphore init failed (possibly too many concurrent threads)');
WRITE_DEBUG('thread ', ptruint(self), ' created semaphore ', ptruint(FSem));
FSuspendEvent := RtlEventCreate;
WRITE_DEBUG('thread ', ptruint(self), ' created RTLEvent ', ptruint(FSuspendEvent));
FSuspended := CreateSuspended;
FThreadReaped := false;
FInitialSuspended := CreateSuspended;
@ -167,13 +165,13 @@ end;
procedure TThread.SysDestroy;
begin
if (FSem = nil) then
if not assigned(FSuspendEvent) then
{ exception in constructor }
exit;
if (FHandle = TThreadID(0)) then
{ another exception in constructor }
begin
SemaphoreDestroy(FSem);
RtlEventDestroy(FSuspendEvent);
exit;
end;
if (FThreadID = GetCurrentThreadID) then
@ -199,7 +197,7 @@ begin
WaitFor;
end;
end;
SemaphoreDestroy(FSem);
RtlEventDestroy(FSuspendEvent);
FFatalException.Free;
FFatalException := nil;
{ threadvars have been released by cthreads.ThreadMain -> DoneThread, or }
@ -222,7 +220,7 @@ begin
begin
if not FSuspended and
(InterLockedExchange(longint(FSuspended),longint(longbool(true))) = longint(longbool(false))) then
SemaphoreWait(FSem)
RtlEventWaitFor(FSuspendEvent)
end
else
begin
@ -236,7 +234,7 @@ begin
if FSuspendedInternal and (InterLockedExchange(longint(FSuspendedInternal),ord(false)) = longint(longbool(true))) then
begin
WRITE_DEBUG('resuming thread after TThread construction',ptruint(self));
SemaphorePost(FSem);
RtlEventSetEvent(FSuspendEvent);
end
else
begin
@ -246,7 +244,7 @@ begin
(InterLockedExchange(longint(FSuspended),longint(false)) <> longint(longbool(false))) then
begin
WRITE_DEBUG('resuming ',ptruint(self));
SemaphorePost(FSem);
RtlEventSetEvent(FSuspendEvent);
end
end
end;