// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package sync

// Export for testing.
var Runtime_Semacquire = runtime_Semacquire
var Runtime_Semrelease = runtime_Semrelease
var Runtime_procPin = runtime_procPin
var Runtime_procUnpin = runtime_procUnpin

// poolDequeue testing.
type PoolDequeue interface {
	PushHead(val any) bool
	PopHead() (any, bool)

		race.Enable()
		fatal("sync: RUnlock of unlocked RWMutex")
	}
	// A writer is pending.
	if rw.readerWait.Add(-1) == 0 {
		// The last reader unblocks the writer.
		runtime_Semrelease(&rw.writerSem, false, 1)
	}
}

// Lock locks rw for writing.
// If the lock is already locked for reading or writing,
// Lock blocks until the lock is available.
func (rw *RWMutex) Lock() {

				return
			}
			// Grab the right to wake someone.
			new = (old - 1<<mutexWaiterShift) | mutexWoken
			if atomic.CompareAndSwapInt32(&m.state, old, new) {
				runtime_Semrelease(&m.sema, false, 1)
				return
			}
			old = m.state
		}
	} else {
		// Starving mode: handoff mutex ownership to the next waiter, and yield

	if wg.state.Load() != state {
		panic("sync: WaitGroup misuse: Add called concurrently with Wait")
	}
	// Reset waiters count to 0.
	wg.state.Store(0)
	for ; w != 0; w-- {
		runtime_Semrelease(&wg.sema, false, 0)
	}
}

// Done decrements the [WaitGroup] counter by one.
func (wg *WaitGroup) Done() {
	wg.Add(-1)
}

// Wait blocks until the [WaitGroup] counter is zero.

//   - gvisor.dev/gvisor
//   - github.com/sagernet/gvisor
//
// Do not remove or change the type signature.
// See go.dev/issue/67401.
//
//go:linkname sync_runtime_Semrelease sync.runtime_Semrelease
func sync_runtime_Semrelease(addr *uint32, handoff bool, skipframes int) {
	semrelease1(addr, handoff, skipframes)
}

//go:linkname sync_runtime_SemacquireMutex sync.runtime_SemacquireMutex

	// Poller may want to unregister fd in readiness notification mechanism,
	// so this must be executed before CloseFunc.
	fd.pd.close()

	err := fd.SysFile.destroy(fd.Sysfd)

	fd.Sysfd = -1
	runtime_Semrelease(&fd.csema)
	return err
}

// Close closes the FD. The underlying file descriptor is closed by the
// destroy method when there are no remaining references.
func (fd *FD) Close() error {

	case kindNet:
		// The net package uses the CloseFunc variable for testing.
		err = CloseFunc(fd.Sysfd)
	default:
		err = syscall.CloseHandle(fd.Sysfd)
	}
	fd.Sysfd = syscall.InvalidHandle
	runtime_Semrelease(&fd.csema)
	return err
}

// Close closes the FD. The underlying file descriptor is closed by
// the destroy method when there are no remaining references.
func (fd *FD) Close() error {