65 lines
1.1 KiB
Go
65 lines
1.1 KiB
Go
package runners
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import (
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"context"
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"time"
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)
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// closedctx is an always closed context.
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var closedctx = func() context.Context {
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ctx := make(chan struct{})
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close(ctx)
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return CancelCtx(ctx)
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}()
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// Closed returns an always closed context.
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func Closed() context.Context {
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return closedctx
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}
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// CtxWithCancel returns a new context.Context impl with cancel.
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func CtxWithCancel() (context.Context, context.CancelFunc) {
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ctx := make(chan struct{})
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cncl := func() { close(ctx) }
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return CancelCtx(ctx), cncl
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}
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// CancelCtx is the simplest possible cancellable context.
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type CancelCtx (<-chan struct{})
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func (CancelCtx) Deadline() (time.Time, bool) {
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return time.Time{}, false
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}
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func (ctx CancelCtx) Done() <-chan struct{} {
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return ctx
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}
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func (ctx CancelCtx) Err() error {
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select {
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case <-ctx:
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return context.Canceled
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default:
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return nil
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}
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}
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func (CancelCtx) Value(key interface{}) interface{} {
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return nil
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}
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func (ctx CancelCtx) String() string {
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var state string
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select {
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case <-ctx:
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state = "closed"
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default:
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state = "open"
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}
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return "CancelCtx{state:" + state + "}"
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}
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func (ctx CancelCtx) GoString() string {
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return "runners." + ctx.String()
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}
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