1 files changed, 0 insertions, 160 deletions
diff --git a/vendor/golang.org/x/sync/semaphore/semaphore.go b/vendor/golang.org/x/sync/semaphore/semaphore.go
deleted file mode 100644
index b618162aa..000000000
--- a/vendor/golang.org/x/sync/semaphore/semaphore.go
+++ /dev/null
@@ -1,160 +0,0 @@
-// Copyright 2017 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 semaphore provides a weighted semaphore implementation.
-package semaphore // import "golang.org/x/sync/semaphore"
-
-import (
-	"container/list"
-	"context"
-	"sync"
-)
-
-type waiter struct {
-	n     int64
-	ready chan<- struct{} // Closed when semaphore acquired.
-}
-
-// NewWeighted creates a new weighted semaphore with the given
-// maximum combined weight for concurrent access.
-func NewWeighted(n int64) *Weighted {
-	w := &Weighted{size: n}
-	return w
-}
-
-// Weighted provides a way to bound concurrent access to a resource.
-// The callers can request access with a given weight.
-type Weighted struct {
-	size    int64
-	cur     int64
-	mu      sync.Mutex
-	waiters list.List
-}
-
-// Acquire acquires the semaphore with a weight of n, blocking until resources
-// are available or ctx is done. On success, returns nil. On failure, returns
-// ctx.Err() and leaves the semaphore unchanged.
-func (s *Weighted) Acquire(ctx context.Context, n int64) error {
-	done := ctx.Done()
-
-	s.mu.Lock()
-	select {
-	case <-done:
-		// ctx becoming done has "happened before" acquiring the semaphore,
-		// whether it became done before the call began or while we were
-		// waiting for the mutex. We prefer to fail even if we could acquire
-		// the mutex without blocking.
-		s.mu.Unlock()
-		return ctx.Err()
-	default:
-	}
-	if s.size-s.cur >= n && s.waiters.Len() == 0 {
-		// Since we hold s.mu and haven't synchronized since checking done, if
-		// ctx becomes done before we return here, it becoming done must have
-		// "happened concurrently" with this call - it cannot "happen before"
-		// we return in this branch. So, we're ok to always acquire here.
-		s.cur += n
-		s.mu.Unlock()
-		return nil
-	}
-
-	if n > s.size {
-		// Don't make other Acquire calls block on one that's doomed to fail.
-		s.mu.Unlock()
-		<-done
-		return ctx.Err()
-	}
-
-	ready := make(chan struct{})
-	w := waiter{n: n, ready: ready}
-	elem := s.waiters.PushBack(w)
-	s.mu.Unlock()
-
-	select {
-	case <-done:
-		s.mu.Lock()
-		select {
-		case <-ready:
-			// Acquired the semaphore after we were canceled.
-			// Pretend we didn't and put the tokens back.
-			s.cur -= n
-			s.notifyWaiters()
-		default:
-			isFront := s.waiters.Front() == elem
-			s.waiters.Remove(elem)
-			// If we're at the front and there're extra tokens left, notify other waiters.
-			if isFront && s.size > s.cur {
-				s.notifyWaiters()
-			}
-		}
-		s.mu.Unlock()
-		return ctx.Err()
-
-	case <-ready:
-		// Acquired the semaphore. Check that ctx isn't already done.
-		// We check the done channel instead of calling ctx.Err because we
-		// already have the channel, and ctx.Err is O(n) with the nesting
-		// depth of ctx.
-		select {
-		case <-done:
-			s.Release(n)
-			return ctx.Err()
-		default:
-		}
-		return nil
-	}
-}
-
-// TryAcquire acquires the semaphore with a weight of n without blocking.
-// On success, returns true. On failure, returns false and leaves the semaphore unchanged.
-func (s *Weighted) TryAcquire(n int64) bool {
-	s.mu.Lock()
-	success := s.size-s.cur >= n && s.waiters.Len() == 0
-	if success {
-		s.cur += n
-	}
-	s.mu.Unlock()
-	return success
-}
-
-// Release releases the semaphore with a weight of n.
-func (s *Weighted) Release(n int64) {
-	s.mu.Lock()
-	s.cur -= n
-	if s.cur < 0 {
-		s.mu.Unlock()
-		panic("semaphore: released more than held")
-	}
-	s.notifyWaiters()
-	s.mu.Unlock()
-}
-
-func (s *Weighted) notifyWaiters() {
-	for {
-		next := s.waiters.Front()
-		if next == nil {
-			break // No more waiters blocked.
-		}
-
-		w := next.Value.(waiter)
-		if s.size-s.cur < w.n {
-			// Not enough tokens for the next waiter.  We could keep going (to try to
-			// find a waiter with a smaller request), but under load that could cause
-			// starvation for large requests; instead, we leave all remaining waiters
-			// blocked.
-			//
-			// Consider a semaphore used as a read-write lock, with N tokens, N
-			// readers, and one writer.  Each reader can Acquire(1) to obtain a read
-			// lock.  The writer can Acquire(N) to obtain a write lock, excluding all
-			// of the readers.  If we allow the readers to jump ahead in the queue,
-			// the writer will starve — there is always one token available for every
-			// reader.
-			break
-		}
-
-		s.cur += w.n
-		s.waiters.Remove(next)
-		close(w.ready)
-	}
-}