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63 lines
1.4 KiB
Go
63 lines
1.4 KiB
Go
/*
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Copyright The containerd Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package local
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import (
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"sync"
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"time"
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"github.com/containerd/containerd/errdefs"
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"github.com/pkg/errors"
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)
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// Handles locking references
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type lock struct {
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since time.Time
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}
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var (
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// locks lets us lock in process
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locks = make(map[string]*lock)
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locksMu sync.Mutex
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)
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func tryLock(ref string) error {
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locksMu.Lock()
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defer locksMu.Unlock()
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if v, ok := locks[ref]; ok {
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// Returning the duration may help developers distinguish dead locks (long duration) from
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// lock contentions (short duration).
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now := time.Now()
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return errors.Wrapf(
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errdefs.ErrUnavailable,
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"ref %s locked for %s (since %s)", ref, now.Sub(v.since), v.since,
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)
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}
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locks[ref] = &lock{time.Now()}
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return nil
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}
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func unlock(ref string) {
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locksMu.Lock()
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defer locksMu.Unlock()
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delete(locks, ref)
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}
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