52 lines
926 B
Go
52 lines
926 B
Go
package locker
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import (
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"context"
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"github.com/sour-is/ev/internal/lg"
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)
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type Locked[T any] struct {
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state chan *T
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}
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// New creates a new locker for the given value.
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func New[T any](initial *T) *Locked[T] {
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s := &Locked[T]{}
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s.state = make(chan *T, 1)
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s.state <- initial
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return s
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}
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// Modify will call the function with the locked value
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func (s *Locked[T]) Modify(ctx context.Context, fn func(context.Context, *T) error) error {
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_, span := lg.Span(ctx)
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defer span.End()
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if ctx.Err() != nil {
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return ctx.Err()
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}
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select {
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case state := <-s.state:
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defer func() { s.state <- state }()
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return fn(ctx, state)
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case <-ctx.Done():
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return ctx.Err()
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}
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}
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// Copy will return a shallow copy of the locked object.
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func (s *Locked[T]) Copy(ctx context.Context) (T, error) {
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var t T
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err := s.Modify(ctx, func(ctx context.Context, c *T) error {
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if c != nil {
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t = *c
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}
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return nil
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})
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return t, err
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}
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