office-gobmx/cppu/source/threadpool/threadpool.hxx
Stephan Bergmann ad0779ed5e Handle uno_threadpool_dispose in parallel with uno_threadpool_putJob
While tracking down the issue discussed in the commit message of
78dc7d982b "Remove a potentially already enqueued
response when a bridge is disposed", it occurred to me that there should be a
race in those

  uno_threadpool_putJob(
    bridge_->getThreadPool(), ...);

calls in binaryurp/source/reader.cxx, when the bridge gets disposed (through
some other thread) between the time the bridge_->getThreadPool() call checks for
the bridge being disposed (in which case it would throw a DisposedException) and
the actual uno_threadpool_putJob call.

I tried to catch that with a previous incarnation of this change
(<https://gerrit.libreoffice.org/c/core/+/96120/1> "Jenkins Slides Through the
Tiny Window"), but couldn't---presumably because this race would be very rare
after all, and the issue I was chasing turned out to be caused by something
different anyway.  Nevertheless, I wanted to address this potential race now.

We can only reliably check for disposed'ness after having locked ThreadPool's
m_mutex in uno_threadpool_putJob -> ThreadPool::addJob, but at which time we can
no longer indicate this condition to the caller---uno_threapool_putJob is part
of the stable URE interface, has a void return type, and should not throw any
exceptions as it is a C function.  However, if the bridge gets disposed, any
threads that would wait for this job (in cppu_threadpool::JobQueue::enter,
either from cppu_threadpool::ORequestThread::run waiting to process new incoming
calls, or from a bridge's call to uno_threadpool_enter waiting for a respose to
an outgoing call) should already learn about the bridge being disposed by
falling out of cppu_threadpool::JobQueue::enter with a null return value.  So it
should be OK if uno_threadpool_putJob silently discards the job in that case.

Change-Id: I36fe996436f55a93d84d66cc0b164e2e45a37e81
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/96120
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>
2020-06-26 10:43:40 +02:00

164 lines
4.7 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* This file is part of the LibreOffice project.
*
* 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/.
*
* This file incorporates work covered by the following license notice:
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed
* with this work for additional information regarding copyright
* ownership. The ASF licenses this file to you under the Apache
* License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0 .
*/
#ifndef INCLUDED_CPPU_SOURCE_THREADPOOL_THREADPOOL_HXX
#define INCLUDED_CPPU_SOURCE_THREADPOOL_THREADPOOL_HXX
#include <vector>
#include <unordered_map>
#include <osl/conditn.hxx>
#include <osl/mutex.hxx>
#include <rtl/byteseq.hxx>
#include <rtl/ref.hxx>
#include <salhelper/simplereferenceobject.hxx>
#include "jobqueue.hxx"
namespace cppu_threadpool {
class ORequestThread;
struct EqualThreadId
{
bool operator () ( const ::rtl::ByteSequence &a , const ::rtl::ByteSequence &b ) const
{
return a == b;
}
};
struct HashThreadId
{
sal_Int32 operator () ( const ::rtl::ByteSequence &a ) const
{
if( a.getLength() >= 4 )
{
return *reinterpret_cast<sal_Int32 const *>(a.getConstArray());
}
return 0;
}
};
typedef std::unordered_map
<
::rtl::ByteSequence, // ThreadID
std::pair < JobQueue * , JobQueue * >,
HashThreadId,
EqualThreadId
> ThreadIdHashMap;
struct WaitingThread
{
osl::Condition condition;
rtl::Reference< ORequestThread > thread;
explicit WaitingThread(
rtl::Reference<ORequestThread> const & theThread);
};
typedef std::deque< struct ::cppu_threadpool::WaitingThread * > WaitingThreadDeque;
class DisposedCallerAdmin;
typedef std::shared_ptr<DisposedCallerAdmin> DisposedCallerAdminHolder;
class DisposedCallerAdmin
{
public:
~DisposedCallerAdmin();
static DisposedCallerAdminHolder const & getInstance();
void dispose( void const * nDisposeId );
void destroy( void const * nDisposeId );
bool isDisposed( void const * nDisposeId );
private:
::osl::Mutex m_mutex;
std::vector< void const * > m_vector;
};
class ThreadAdmin
{
public:
ThreadAdmin();
~ThreadAdmin ();
bool add( rtl::Reference< ORequestThread > const & );
void remove( rtl::Reference< ORequestThread > const & );
void join();
void remove_locked( rtl::Reference< ORequestThread > const & );
::osl::Mutex m_mutex;
private:
std::deque< rtl::Reference< ORequestThread > > m_deque;
bool m_disposed;
};
class ThreadPool;
typedef rtl::Reference<ThreadPool> ThreadPoolHolder;
class ThreadPool: public salhelper::SimpleReferenceObject
{
public:
ThreadPool();
virtual ~ThreadPool() override;
void dispose( void const * nDisposeId );
void destroy( void const * nDisposeId );
bool addJob( const ::rtl::ByteSequence &aThreadId,
bool bAsynchron,
void *pThreadSpecificData,
RequestFun * doRequest,
void const * disposeId );
void prepare( const ::rtl::ByteSequence &aThreadId );
void * enter( const ::rtl::ByteSequence &aThreadId, void const * nDisposeId );
/********
* @return true, if queue could be successfully revoked.
********/
bool revokeQueue( const ::rtl::ByteSequence & aThreadId , bool bAsynchron );
void waitInPool( rtl::Reference< ORequestThread > const & pThread );
void joinWorkers();
ThreadAdmin & getThreadAdmin() { return m_aThreadAdmin; }
private:
bool createThread( JobQueue *pQueue, const ::rtl::ByteSequence &aThreadId, bool bAsynchron);
ThreadIdHashMap m_mapQueue;
::osl::Mutex m_mutex;
::osl::Mutex m_mutexWaitingThreadList;
WaitingThreadDeque m_dequeThreads;
DisposedCallerAdminHolder m_DisposedCallerAdmin;
ThreadAdmin m_aThreadAdmin;
};
} // end namespace cppu_threadpool
#endif
/* vim:set shiftwidth=4 softtabstop=4 expandtab: */