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Diffstat (limited to 'gcc-4.8.1/libgo/go/sync/rwmutex.go')
-rw-r--r--gcc-4.8.1/libgo/go/sync/rwmutex.go124
1 files changed, 0 insertions, 124 deletions
diff --git a/gcc-4.8.1/libgo/go/sync/rwmutex.go b/gcc-4.8.1/libgo/go/sync/rwmutex.go
deleted file mode 100644
index b494c6435..000000000
--- a/gcc-4.8.1/libgo/go/sync/rwmutex.go
+++ /dev/null
@@ -1,124 +0,0 @@
-// Copyright 2009 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package sync
-
-import (
- "sync/atomic"
- "unsafe"
-)
-
-// An RWMutex is a reader/writer mutual exclusion lock.
-// The lock can be held by an arbitrary number of readers
-// or a single writer.
-// RWMutexes can be created as part of other
-// structures; the zero value for a RWMutex is
-// an unlocked mutex.
-type RWMutex struct {
- w Mutex // held if there are pending writers
- writerSem uint32 // semaphore for writers to wait for completing readers
- readerSem uint32 // semaphore for readers to wait for completing writers
- readerCount int32 // number of pending readers
- readerWait int32 // number of departing readers
-}
-
-const rwmutexMaxReaders = 1 << 30
-
-// RLock locks rw for reading.
-func (rw *RWMutex) RLock() {
- if raceenabled {
- raceDisable()
- }
- if atomic.AddInt32(&rw.readerCount, 1) < 0 {
- // A writer is pending, wait for it.
- runtime_Semacquire(&rw.readerSem)
- }
- if raceenabled {
- raceEnable()
- raceAcquire(unsafe.Pointer(&rw.readerSem))
- }
-}
-
-// RUnlock undoes a single RLock call;
-// it does not affect other simultaneous readers.
-// It is a run-time error if rw is not locked for reading
-// on entry to RUnlock.
-func (rw *RWMutex) RUnlock() {
- if raceenabled {
- raceReleaseMerge(unsafe.Pointer(&rw.writerSem))
- raceDisable()
- }
- if atomic.AddInt32(&rw.readerCount, -1) < 0 {
- // A writer is pending.
- if atomic.AddInt32(&rw.readerWait, -1) == 0 {
- // The last reader unblocks the writer.
- runtime_Semrelease(&rw.writerSem)
- }
- }
- if raceenabled {
- raceEnable()
- }
-}
-
-// Lock locks rw for writing.
-// If the lock is already locked for reading or writing,
-// Lock blocks until the lock is available.
-// To ensure that the lock eventually becomes available,
-// a blocked Lock call excludes new readers from acquiring
-// the lock.
-func (rw *RWMutex) Lock() {
- if raceenabled {
- raceDisable()
- }
- // First, resolve competition with other writers.
- rw.w.Lock()
- // Announce to readers there is a pending writer.
- r := atomic.AddInt32(&rw.readerCount, -rwmutexMaxReaders) + rwmutexMaxReaders
- // Wait for active readers.
- if r != 0 && atomic.AddInt32(&rw.readerWait, r) != 0 {
- runtime_Semacquire(&rw.writerSem)
- }
- if raceenabled {
- raceEnable()
- raceAcquire(unsafe.Pointer(&rw.readerSem))
- raceAcquire(unsafe.Pointer(&rw.writerSem))
- }
-}
-
-// Unlock unlocks rw for writing. It is a run-time error if rw is
-// not locked for writing on entry to Unlock.
-//
-// As with Mutexes, a locked RWMutex is not associated with a particular
-// goroutine. One goroutine may RLock (Lock) an RWMutex and then
-// arrange for another goroutine to RUnlock (Unlock) it.
-func (rw *RWMutex) Unlock() {
- if raceenabled {
- raceRelease(unsafe.Pointer(&rw.readerSem))
- raceRelease(unsafe.Pointer(&rw.writerSem))
- raceDisable()
- }
-
- // Announce to readers there is no active writer.
- r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders)
- // Unblock blocked readers, if any.
- for i := 0; i < int(r); i++ {
- runtime_Semrelease(&rw.readerSem)
- }
- // Allow other writers to proceed.
- rw.w.Unlock()
- if raceenabled {
- raceEnable()
- }
-}
-
-// RLocker returns a Locker interface that implements
-// the Lock and Unlock methods by calling rw.RLock and rw.RUnlock.
-func (rw *RWMutex) RLocker() Locker {
- return (*rlocker)(rw)
-}
-
-type rlocker RWMutex
-
-func (r *rlocker) Lock() { (*RWMutex)(r).RLock() }
-func (r *rlocker) Unlock() { (*RWMutex)(r).RUnlock() }