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78 lines
2.1 KiB
Go
78 lines
2.1 KiB
Go
// Copyright (c) 2015-2023 MinIO, Inc.
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//
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// This file is part of MinIO Object Storage stack
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//
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// This program is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Affero General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// This program is distributed in the hope that it will be useful
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Affero General Public License for more details.
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//
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// You should have received a copy of the GNU Affero General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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package once
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import (
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"context"
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"sync"
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"sync/atomic"
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)
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// Inspired from Golang sync.Once but it is only marked
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// initialized when the provided function returns nil.
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// Init represents the structure.
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type Init struct {
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done uint32
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m sync.Mutex
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}
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// Do is similar to sync.Once.Do - makes one successful
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// call to the function. ie, it invokes the function
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// if it is not successful yet.
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func (l *Init) Do(f func() error) error {
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if atomic.LoadUint32(&l.done) == 0 {
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return l.do(f)
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}
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return nil
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}
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func (l *Init) do(f func() error) error {
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l.m.Lock()
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defer l.m.Unlock()
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if atomic.LoadUint32(&l.done) == 0 {
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if err := f(); err != nil {
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return err
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}
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// Mark as done only when f() is successful
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atomic.StoreUint32(&l.done, 1)
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}
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return nil
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}
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// DoWithContext is similar to Do except that it accepts a context as an argument to be passed.
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func (l *Init) DoWithContext(ctx context.Context, f func(context.Context) error) error {
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if atomic.LoadUint32(&l.done) == 0 {
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return l.doWithContext(ctx, f)
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}
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return nil
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}
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func (l *Init) doWithContext(ctx context.Context, f func(context.Context) error) error {
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l.m.Lock()
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defer l.m.Unlock()
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if atomic.LoadUint32(&l.done) == 0 {
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if err := f(ctx); err != nil {
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return err
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}
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// Mark as done only when f() is successful
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atomic.StoreUint32(&l.done, 1)
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}
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return nil
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}
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