96 lines
3.0 KiB
Go
96 lines
3.0 KiB
Go
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// Copyright 2020-2021 Buf Technologies, Inc.
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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package filelock
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import (
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"context"
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"time"
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)
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const (
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// DefaultLockTimeout is the default lock timeout.
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DefaultLockTimeout = 3 * time.Second
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// DefaultLockRetryDelay is the default lock retry delay.
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DefaultLockRetryDelay = 200 * time.Millisecond
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)
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// Unlocker unlocks a file lock.
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type Unlocker interface {
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Unlock() error
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}
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// Lock locks a file lock.
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//
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// Use in cases where you need a lock for a specific system file, such as in testing,
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// otherwise use a Locker to manage your file locks.
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func Lock(ctx context.Context, filePath string, options ...LockOption) (Unlocker, error) {
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return lock(ctx, filePath, options...)
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}
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// RLock read-locks a file lock.
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//
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// Use in cases where you need a lock for a specific system file, such as in testing,
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// otherwise use a Locker to manage your file locks.
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func RLock(ctx context.Context, filePath string, options ...LockOption) (Unlocker, error) {
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return rlock(ctx, filePath, options...)
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}
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// Locker provides file locks.
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type Locker interface {
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// Lock locks a file lock within the root directory of the Locker.
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//
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// The given path must be normalized and relative.
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Lock(ctx context.Context, path string, options ...LockOption) (Unlocker, error)
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// RLock read-locks a file lock within the root directory of the Locker.
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//
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// The given path must be normalized and relative.
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RLock(ctx context.Context, path string, options ...LockOption) (Unlocker, error)
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}
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// NewLocker returns a new Locker for the given root directory path.
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//
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// The root directory path should generally be a data directory path.
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// The root directory must exist.
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func NewLocker(rootDirPath string) (Locker, error) {
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return newLocker(rootDirPath)
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}
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// LockOption is an option for lock.
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type LockOption func(*lockOptions)
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// LockWithTimeout returns a new LockOption that sets the lock timeout.
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//
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// Lock returns error if the lock cannot be acquired after this amount of time.
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// If this is set to 0, the lock will never timeout.
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func LockWithTimeout(timeout time.Duration) LockOption {
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return func(lockOptions *lockOptions) {
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lockOptions.timeout = timeout
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}
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}
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// LockWithRetryDelay returns a new LockOption that sets the lock retry delay.
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//
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// Lock will try to lock on this delay up until the lock timeout.
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func LockWithRetryDelay(retryDelay time.Duration) LockOption {
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return func(lockOptions *lockOptions) {
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lockOptions.retryDelay = retryDelay
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}
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}
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// NewNopLocker returns a new no-op Locker.
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func NewNopLocker() Locker {
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return newNopLocker()
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}
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