50 lines
976 B
Go
50 lines
976 B
Go
// +build !plan9
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package sftp
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import "sync"
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// stringLock locks for string IDs passed in
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type stringLock struct {
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mu sync.Mutex // mutex to protect below
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locks map[string]chan struct{} // map of locks
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}
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// newStringLock creates a stringLock
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func newStringLock() *stringLock {
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return &stringLock{
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locks: make(map[string]chan struct{}),
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}
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}
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// Lock locks on the id passed in
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func (l *stringLock) Lock(ID string) {
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l.mu.Lock()
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for {
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ch, ok := l.locks[ID]
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if !ok {
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break
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}
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// Wait for the channel to be closed
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l.mu.Unlock()
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// fs.Logf(nil, "Waiting for stringLock on %q", ID)
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<-ch
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l.mu.Lock()
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}
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l.locks[ID] = make(chan struct{})
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l.mu.Unlock()
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}
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// Unlock unlocks on the id passed in. Will panic if Lock with the
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// given id wasn't called first.
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func (l *stringLock) Unlock(ID string) {
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l.mu.Lock()
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ch, ok := l.locks[ID]
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if !ok {
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panic("stringLock: Unlock before Lock")
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}
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close(ch)
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delete(l.locks, ID)
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l.mu.Unlock()
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}
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