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https://gitlab.com/pulsechaincom/go-pulse.git
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edb1937cf7
This change removes misuses of sync.WaitGroup in BlockChain. Before this change, block insertion modified the WaitGroup counter in order to ensure that Stop would wait for pending operations to complete. This was racy and could even lead to crashes if Stop was called at an unfortunate time. The issue is resolved by adding a specialized 'closable' mutex, which prevents chain modifications after stopping while also synchronizing writers with each other. Co-authored-by: Felix Lange <fjl@twurst.com>
65 lines
1.7 KiB
Go
65 lines
1.7 KiB
Go
// Copyright 2021 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser 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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// The go-ethereum library 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 Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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// Package syncx contains exotic synchronization primitives.
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package syncx
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// ClosableMutex is a mutex that can also be closed.
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// Once closed, it can never be taken again.
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type ClosableMutex struct {
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ch chan struct{}
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}
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func NewClosableMutex() *ClosableMutex {
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ch := make(chan struct{}, 1)
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ch <- struct{}{}
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return &ClosableMutex{ch}
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}
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// TryLock attempts to lock cm.
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// If the mutex is closed, TryLock returns false.
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func (cm *ClosableMutex) TryLock() bool {
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_, ok := <-cm.ch
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return ok
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}
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// MustLock locks cm.
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// If the mutex is closed, MustLock panics.
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func (cm *ClosableMutex) MustLock() {
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_, ok := <-cm.ch
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if !ok {
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panic("mutex closed")
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}
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}
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// Unlock unlocks cm.
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func (cm *ClosableMutex) Unlock() {
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select {
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case cm.ch <- struct{}{}:
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default:
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panic("Unlock of already-unlocked ClosableMutex")
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}
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}
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// Close locks the mutex, then closes it.
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func (cm *ClosableMutex) Close() {
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_, ok := <-cm.ch
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if !ok {
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panic("Close of already-closed ClosableMutex")
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}
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close(cm.ch)
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}
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