diff options
Diffstat (limited to 'cpp/src/IceUtil/RWRecMutex.cpp')
| -rw-r--r-- | cpp/src/IceUtil/RWRecMutex.cpp | 710 |
1 files changed, 355 insertions, 355 deletions
diff --git a/cpp/src/IceUtil/RWRecMutex.cpp b/cpp/src/IceUtil/RWRecMutex.cpp index b8275b2b9f8..ef632a347ec 100644 --- a/cpp/src/IceUtil/RWRecMutex.cpp +++ b/cpp/src/IceUtil/RWRecMutex.cpp @@ -1,355 +1,355 @@ -// ********************************************************************** -// -// Copyright (c) 2001 -// Mutable Realms, Inc. -// Huntsville, AL, USA -// -// All Rights Reserved -// -// ********************************************************************** - -#include <IceUtil/RWRecMutex.h> -#include <IceUtil/Exception.h> -#include <IceUtil/Time.h> - -#include <assert.h> - -IceUtil::RWRecMutex::RWRecMutex() : - _count(0), - _waitingWriters(0) -{ -} - -IceUtil::RWRecMutex::~RWRecMutex() -{ -} - -void -IceUtil::RWRecMutex::readlock() const -{ - Mutex::Lock lock(_mutex); - - // - // Wait while a writer holds the lock or while writers are waiting - // to get the lock. - // - while(_count < 0 || _waitingWriters != 0) - { - _readers.wait(lock); - } - _count++; -} - -void -IceUtil::RWRecMutex::tryReadlock() const -{ - Mutex::Lock lock(_mutex); - - // - // Would block if a writer holds the lock or if writers are - // waiting to get the lock. - // - if(_count < 0 || _waitingWriters != 0) - { - throw LockedException(__FILE__, __LINE__); - } - _count++; -} - -void -IceUtil::RWRecMutex::timedTryReadlock(const Time& timeout) const -{ - Mutex::Lock lock(_mutex); - - // - // Wait while a writer holds the lock or while writers are waiting - // to get the lock. - // - Time end = Time::now() + timeout; - while(_count < 0 || _waitingWriters != 0) - { - Time remainder = end - Time::now(); - if(remainder > Time()) - { - _readers.timedWait(lock, remainder); - } - else - { - throw LockedException(__FILE__, __LINE__); - } - } - - _count++; -} - -void -IceUtil::RWRecMutex::writelock() const -{ - Mutex::Lock lock(_mutex); - - // - // If the mutex is already write locked by this writer then - // decrement _count, and return. - // - if(_count < 0 && _writerControl == ThreadControl()) - { - --_count; - return; - } - - // - // Wait for the lock to become available and increment the number - // of waiting writers. - // - while(_count != 0) - { - _waitingWriters++; - try - { - _writers.wait(lock); - } - catch(...) - { - --_waitingWriters; - throw; - } - _waitingWriters--; - } - - // - // Got the lock, indicate it's held by a writer. - // - _count = -1; -} - -void -IceUtil::RWRecMutex::tryWritelock() const -{ - Mutex::Lock lock(_mutex); - - // - // If the mutex is already write locked by this writer then - // decrement _count, and return. - // - if(_count < 0 && _writerControl == ThreadControl()) - { - --_count; - return; - } - - // - // If there are readers or other writers then the call would block. - // - if(_count != 0) - { - throw LockedException(__FILE__, __LINE__); - } - - // - // Got the lock, indicate it's held by a writer. - // - _count = -1; -} - -void -IceUtil::RWRecMutex::timedTryWritelock(const Time& timeout) const -{ - Mutex::Lock lock(_mutex); - - // - // If the mutex is already write locked by this writer then - // decrement _count, and return. - // - if(_count < 0 && _writerControl == ThreadControl()) - { - --_count; - return; - } - - // - // Wait for the lock to become available and increment the number - // of waiting writers. - // - Time end = Time::now() + timeout; - while(_count != 0) - { - Time remainder = end - Time::now(); - if(remainder > Time()) - { - _waitingWriters++; - try - { - _writers.timedWait(lock, remainder); - } - catch(...) - { - --_waitingWriters; - throw; - } - _waitingWriters--; - } - else - { - throw LockedException(__FILE__, __LINE__); - } - } - - // - // Got the lock, indicate it's held by a writer. - // - _count = -1; -} - -void -IceUtil::RWRecMutex::unlock() const -{ - bool ww; - bool wr; - { - Mutex::Lock lock(_mutex); - - assert(_count != 0); - - // - // If _count < 0, the calling thread is a writer that holds the - // lock, so release the lock. Otherwise, _count is guaranteed to - // be > 0, so the calling thread is a reader releasing the lock. - // - if(_count < 0) - { - // - // Writer called unlock - // - ++_count; - - // - // If the write lock wasn't totally released we're done. - // - if(_count != 0) - { - return; - } - } - else - { - // - // Reader called unlock - // - --_count; - } - - // - // Writers are waiting (ww) if _waitingWriters > 0. In that - // case, it's OK to let another writer into the region once there - // are no more readers (_count == 0). Otherwise, no writers are - // waiting but readers may be waiting (wr). - // - ww = (_waitingWriters != 0 && _count == 0); - wr = (_waitingWriters == 0); - } - - // - // Wake up a waiting writer if there is one. If not, wake up all - // readers (just in case -- there may be none). - // - if(ww) - { - // - // Wake writer - // - _writers.signal(); - } - else if(wr) - { - // - // Wake readers - // - _readers.broadcast(); - } -} - -void -IceUtil::RWRecMutex::upgrade() const -{ - Mutex::Lock lock(_mutex); - - // - // Reader called unlock - // - assert(_count > 0); - --_count; - - // - // Wait to acquire the write lock. - // - while(_count != 0) - { - _waitingWriters++; - try - { - _writers.wait(lock); - } - catch(...) - { - --_waitingWriters; - throw; - } - _waitingWriters--; - - - } - - // - // Got the lock, indicate it's held by a writer. - // - _count = -1; -} - -void -IceUtil::RWRecMutex::timedUpgrade(const Time& timeout) const -{ - Mutex::Lock lock(_mutex); - - // - // Reader called unlock - // - assert(_count > 0); - --_count; - - // - // Wait to acquire the write lock. - // - Time end = Time::now() + timeout; - while(_count != 0) - { - Time remainder = end - Time::now(); - if(remainder > Time()) - { - _waitingWriters++; - try - { - _writers.timedWait(lock, remainder); - } - catch(...) - { - --_waitingWriters; - throw; - } - _waitingWriters--; - } - else - { - // - // If a timeout occurred then the lock wasn't acquired. Ensure - // that the _count is increased again before returning. - // - ++_count; - throw LockedException(__FILE__, __LINE__); - } - } - - // - // Got the lock, indicate it's held by a writer. - // - _count = -1; -} +// **********************************************************************
+//
+// Copyright (c) 2001
+// Mutable Realms, Inc.
+// Huntsville, AL, USA
+//
+// All Rights Reserved
+//
+// **********************************************************************
+
+#include <IceUtil/RWRecMutex.h>
+#include <IceUtil/Exception.h>
+#include <IceUtil/Time.h>
+
+#include <assert.h>
+
+IceUtil::RWRecMutex::RWRecMutex() :
+ _count(0),
+ _waitingWriters(0)
+{
+}
+
+IceUtil::RWRecMutex::~RWRecMutex()
+{
+}
+
+void
+IceUtil::RWRecMutex::readlock() const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // Wait while a writer holds the lock or while writers are waiting
+ // to get the lock.
+ //
+ while(_count < 0 || _waitingWriters != 0)
+ {
+ _readers.wait(lock);
+ }
+ _count++;
+}
+
+void
+IceUtil::RWRecMutex::tryReadlock() const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // Would block if a writer holds the lock or if writers are
+ // waiting to get the lock.
+ //
+ if(_count < 0 || _waitingWriters != 0)
+ {
+ throw ThreadLockedException(__FILE__, __LINE__);
+ }
+ _count++;
+}
+
+void
+IceUtil::RWRecMutex::timedTryReadlock(const Time& timeout) const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // Wait while a writer holds the lock or while writers are waiting
+ // to get the lock.
+ //
+ Time end = Time::now() + timeout;
+ while(_count < 0 || _waitingWriters != 0)
+ {
+ Time remainder = end - Time::now();
+ if(remainder > Time())
+ {
+ _readers.timedWait(lock, remainder);
+ }
+ else
+ {
+ throw ThreadLockedException(__FILE__, __LINE__);
+ }
+ }
+
+ _count++;
+}
+
+void
+IceUtil::RWRecMutex::writelock() const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // If the mutex is already write locked by this writer then
+ // decrement _count, and return.
+ //
+ if(_count < 0 && _writerControl == ThreadControl())
+ {
+ --_count;
+ return;
+ }
+
+ //
+ // Wait for the lock to become available and increment the number
+ // of waiting writers.
+ //
+ while(_count != 0)
+ {
+ _waitingWriters++;
+ try
+ {
+ _writers.wait(lock);
+ }
+ catch(...)
+ {
+ --_waitingWriters;
+ throw;
+ }
+ _waitingWriters--;
+ }
+
+ //
+ // Got the lock, indicate it's held by a writer.
+ //
+ _count = -1;
+}
+
+void
+IceUtil::RWRecMutex::tryWritelock() const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // If the mutex is already write locked by this writer then
+ // decrement _count, and return.
+ //
+ if(_count < 0 && _writerControl == ThreadControl())
+ {
+ --_count;
+ return;
+ }
+
+ //
+ // If there are readers or other writers then the call would block.
+ //
+ if(_count != 0)
+ {
+ throw ThreadLockedException(__FILE__, __LINE__);
+ }
+
+ //
+ // Got the lock, indicate it's held by a writer.
+ //
+ _count = -1;
+}
+
+void
+IceUtil::RWRecMutex::timedTryWritelock(const Time& timeout) const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // If the mutex is already write locked by this writer then
+ // decrement _count, and return.
+ //
+ if(_count < 0 && _writerControl == ThreadControl())
+ {
+ --_count;
+ return;
+ }
+
+ //
+ // Wait for the lock to become available and increment the number
+ // of waiting writers.
+ //
+ Time end = Time::now() + timeout;
+ while(_count != 0)
+ {
+ Time remainder = end - Time::now();
+ if(remainder > Time())
+ {
+ _waitingWriters++;
+ try
+ {
+ _writers.timedWait(lock, remainder);
+ }
+ catch(...)
+ {
+ --_waitingWriters;
+ throw;
+ }
+ _waitingWriters--;
+ }
+ else
+ {
+ throw ThreadLockedException(__FILE__, __LINE__);
+ }
+ }
+
+ //
+ // Got the lock, indicate it's held by a writer.
+ //
+ _count = -1;
+}
+
+void
+IceUtil::RWRecMutex::unlock() const
+{
+ bool ww;
+ bool wr;
+ {
+ Mutex::Lock lock(_mutex);
+
+ assert(_count != 0);
+
+ //
+ // If _count < 0, the calling thread is a writer that holds the
+ // lock, so release the lock. Otherwise, _count is guaranteed to
+ // be > 0, so the calling thread is a reader releasing the lock.
+ //
+ if(_count < 0)
+ {
+ //
+ // Writer called unlock
+ //
+ ++_count;
+
+ //
+ // If the write lock wasn't totally released we're done.
+ //
+ if(_count != 0)
+ {
+ return;
+ }
+ }
+ else
+ {
+ //
+ // Reader called unlock
+ //
+ --_count;
+ }
+
+ //
+ // Writers are waiting (ww) if _waitingWriters > 0. In that
+ // case, it's OK to let another writer into the region once there
+ // are no more readers (_count == 0). Otherwise, no writers are
+ // waiting but readers may be waiting (wr).
+ //
+ ww = (_waitingWriters != 0 && _count == 0);
+ wr = (_waitingWriters == 0);
+ }
+
+ //
+ // Wake up a waiting writer if there is one. If not, wake up all
+ // readers (just in case -- there may be none).
+ //
+ if(ww)
+ {
+ //
+ // Wake writer
+ //
+ _writers.signal();
+ }
+ else if(wr)
+ {
+ //
+ // Wake readers
+ //
+ _readers.broadcast();
+ }
+}
+
+void
+IceUtil::RWRecMutex::upgrade() const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // Reader called unlock
+ //
+ assert(_count > 0);
+ --_count;
+
+ //
+ // Wait to acquire the write lock.
+ //
+ while(_count != 0)
+ {
+ _waitingWriters++;
+ try
+ {
+ _writers.wait(lock);
+ }
+ catch(...)
+ {
+ --_waitingWriters;
+ throw;
+ }
+ _waitingWriters--;
+
+
+ }
+
+ //
+ // Got the lock, indicate it's held by a writer.
+ //
+ _count = -1;
+}
+
+void
+IceUtil::RWRecMutex::timedUpgrade(const Time& timeout) const
+{
+ Mutex::Lock lock(_mutex);
+
+ //
+ // Reader called unlock
+ //
+ assert(_count > 0);
+ --_count;
+
+ //
+ // Wait to acquire the write lock.
+ //
+ Time end = Time::now() + timeout;
+ while(_count != 0)
+ {
+ Time remainder = end - Time::now();
+ if(remainder > Time())
+ {
+ _waitingWriters++;
+ try
+ {
+ _writers.timedWait(lock, remainder);
+ }
+ catch(...)
+ {
+ --_waitingWriters;
+ throw;
+ }
+ _waitingWriters--;
+ }
+ else
+ {
+ //
+ // If a timeout occurred then the lock wasn't acquired. Ensure
+ // that the _count is increased again before returning.
+ //
+ ++_count;
+ throw ThreadLockedException(__FILE__, __LINE__);
+ }
+ }
+
+ //
+ // Got the lock, indicate it's held by a writer.
+ //
+ _count = -1;
+}
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