48 lines
946 B
Go
48 lines
946 B
Go
package errors
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import (
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"sync/atomic"
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"unsafe"
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)
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// OnceError is an error structure that supports safe multi
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// threaded usage and setting only once (until reset).
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type OnceError struct{ err unsafe.Pointer }
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// NewOnce returns a new OnceError instance.
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func NewOnce() OnceError {
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return OnceError{
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err: nil,
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}
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}
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// Store will safely set the OnceError to value, no-op if nil.
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func (e *OnceError) Store(err error) {
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// Nothing to do
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if err == nil {
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return
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}
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// Only set if not already
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atomic.CompareAndSwapPointer(
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&e.err,
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nil,
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unsafe.Pointer(&err),
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)
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}
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// Load will load the currently stored error.
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func (e *OnceError) Load() error {
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return *(*error)(atomic.LoadPointer(&e.err))
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}
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// IsSet returns whether OnceError has been set.
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func (e *OnceError) IsSet() bool {
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return (atomic.LoadPointer(&e.err) != nil)
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}
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// Reset will reset the OnceError value.
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func (e *OnceError) Reset() {
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atomic.StorePointer(&e.err, nil)
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}
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