47 lines
1.1 KiB
Go
47 lines
1.1 KiB
Go
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// Package limiter provides concurrency limiters.
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package limiter
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// Fixed is a simple channel-based concurrency limiter. It uses a fixed
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// size channel to limit callers from proceeding until there is a value available
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// in the channel. If all are in-use, the caller blocks until one is freed.
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type Fixed chan struct{}
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func NewFixed(limit int) Fixed {
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return make(Fixed, limit)
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}
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// Idle returns true if the limiter has all its capacity is available.
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func (t Fixed) Idle() bool {
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return len(t) == cap(t)
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}
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// Available returns the number of available tokens that may be taken.
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func (t Fixed) Available() int {
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return cap(t) - len(t)
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}
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// Capacity returns the number of tokens can be taken.
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func (t Fixed) Capacity() int {
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return cap(t)
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}
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// TryTake attempts to take a token and return true if successful, otherwise returns false.
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func (t Fixed) TryTake() bool {
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select {
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case t <- struct{}{}:
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return true
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default:
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return false
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}
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}
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// Take attempts to take a token and blocks until one is available.
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func (t Fixed) Take() {
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t <- struct{}{}
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}
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// Release releases a token back to the limiter.
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func (t Fixed) Release() {
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<-t
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}
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