1 files changed, 170 insertions, 0 deletions
diff --git a/src/mongo/util/concurrency/rwlockimpl.h b/src/mongo/util/concurrency/rwlockimpl.h
new file mode 100644
index 00000000000..4e07231447b
--- /dev/null
+++ b/src/mongo/util/concurrency/rwlockimpl.h
@@ -0,0 +1,170 @@
+// @file rwlockimpl.h
+
+#pragma once
+
+#if defined(MONGO_USE_SRW_ON_WINDOWS) && defined(_WIN32)
+
+// windows slimreaderwriter version.  newer windows versions only
+
+namespace mongo { 
+    class RWLockBase : boost::noncopyable {
+        SRWLOCK _lock;
+    protected:
+        RWLockBase() { InitializeSRWLock(&_lock); }
+        ~RWLockBase() {
+            // no special action needed to destroy a SRWLOCK
+        }
+        void lock()          { AcquireSRWLockExclusive(&_lock); }
+        void unlock()        { ReleaseSRWLockExclusive(&_lock); }
+        void lock_shared()   { AcquireSRWLockShared(&_lock); }
+        void unlock_shared() { ReleaseSRWLockShared(&_lock); }
+        bool lock_shared_try( int millis ) {
+            if( TryAcquireSRWLockShared(&_lock) )
+                return true;
+            if( millis == 0 )
+                return false;
+            unsigned long long end = curTimeMicros64() + millis*1000;
+            while( 1 ) {
+                Sleep(1);
+                if( TryAcquireSRWLockShared(&_lock) )
+                    return true;
+                if( curTimeMicros64() >= end )
+                    break;
+            }
+            return false;
+        }
+        bool lock_try( int millis = 0 ) {
+            if( TryAcquireSRWLockExclusive(&_lock) ) // quick check to optimistically avoid calling curTimeMicros64
+                return true;
+            if( millis == 0 )
+                return false;
+            unsigned long long end = curTimeMicros64() + millis*1000;
+            do {
+                Sleep(1);
+                if( TryAcquireSRWLockExclusive(&_lock) )
+                    return true;
+            } while( curTimeMicros64() < end );
+            return false;
+        }
+        // no upgradable for this impl
+        void lockAsUpgradable() { lock(); }
+        void unlockFromUpgradable() { unlock(); }
+        void upgrade() { }
+    public:
+        const char * implType() const { return "WINSRW"; }
+    };
+}
+
+#elif( BOOST_VERSION < 103500 ) 
+
+# if defined(_WIN32)
+#  error need boost >= 1.35 for windows
+# endif
+
+// pthreads version
+
+# include <pthread.h>
+
+namespace mongo { 
+    class RWLockBase : boost::noncopyable {
+        pthread_rwlock_t _lock;
+        static void check( int x ) {
+            if( x == 0 ) return;
+            log() << "pthread rwlock failed: " << x << endl;
+            assert( x == 0 );
+        }        
+
+        ~RWLockBase() {
+            if ( ! StaticObserver::_destroyingStatics ) {
+                wassert( pthread_rwlock_destroy( &_lock ) == 0 ); // wassert as don't want to throw from a destructor
+            }
+        }
+
+    protected:
+        RWLockBase() {
+            check( pthread_rwlock_init( &_lock , 0 ) );
+        }
+
+        void lock() { check( pthread_rwlock_wrlock( &_lock ) ); }
+        void unlock() { check( pthread_rwlock_unlock( &_lock ) ); }
+        void lock_shared() { check( pthread_rwlock_rdlock( &_lock ) ); }
+        void unlock_shared() { check( pthread_rwlock_unlock( &_lock ) ); }
+        bool lock_shared_try( int millis ) { return _try( millis , false ); }
+        bool lock_try( int millis = 0 ) { return _try( millis , true ); }
+        bool _try( int millis , bool write ) {
+            while ( true ) {
+                int x = write ?
+                        pthread_rwlock_trywrlock( &_lock ) :
+                        pthread_rwlock_tryrdlock( &_lock );
+                if ( x <= 0 )
+                    return true;
+                if ( millis-- <= 0 )
+                    return false;
+                if ( x == EBUSY ) {
+                    sleepmillis(1);
+                    continue;
+                }
+                check(x);
+            }
+            return false;
+        }
+        // no upgradable for this impl
+        void lockAsUpgradable() { lock(); }
+        void unlockFromUpgradable() { unlock(); }
+        void upgrade() { }
+    public:
+        const char * implType() const { return "posix"; }
+    };
+}
+
+#else
+
+// Boost version
+
+# if defined(_WIN32)
+#  include "shared_mutex_win.hpp"
+namespace mongo { typedef boost::modified_shared_mutex shared_mutex; }
+# else
+#  include <boost/thread/shared_mutex.hpp>
+namespace mongo { using boost::shared_mutex; }
+# endif
+# undef assert
+# define assert MONGO_assert
+
+namespace mongo { 
+    class RWLockBase : boost::noncopyable {
+        shared_mutex _m;
+    protected:
+        void lock() {
+             _m.lock();
+        }
+        void unlock() {
+            _m.unlock();
+        }
+        void lockAsUpgradable() { 
+            _m.lock_upgrade();
+        }
+        void unlockFromUpgradable() { // upgradable -> unlocked
+            _m.unlock_upgrade();
+        }
+        void upgrade() { // upgradable -> exclusive lock
+            _m.unlock_upgrade_and_lock();
+        }
+        void lock_shared() {
+            _m.lock_shared();
+        }
+        void unlock_shared() {
+            _m.unlock_shared();
+        }
+        bool lock_shared_try( int millis ) {
+            return _m.timed_lock_shared( boost::posix_time::milliseconds(millis) );
+        }
+        bool lock_try( int millis = 0 ) {
+            return _m.timed_lock( boost::posix_time::milliseconds(millis) );
+        }
+    public:
+        const char * implType() const { return "boost"; }
+    };
+}
+
+#endif