mirror of https://github.com/restic/restic.git
29 lines
558 B
Go
29 lines
558 B
Go
package backend
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import "restic/errors"
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// Semaphore limits access to a restricted resource.
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type Semaphore struct {
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ch chan struct{}
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}
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// NewSemaphore returns a new semaphore with capacity n.
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func NewSemaphore(n uint) (*Semaphore, error) {
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if n <= 0 {
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return nil, errors.New("must be a positive number")
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}
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return &Semaphore{
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ch: make(chan struct{}, n),
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}, nil
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}
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// GetToken blocks until a Token is available.
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func (s *Semaphore) GetToken() {
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s.ch <- struct{}{}
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}
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// ReleaseToken returns a token.
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func (s *Semaphore) ReleaseToken() {
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<-s.ch
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}
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