Ilia Denisov
45 lines
1.4 KiB
Go
45 lines
1.4 KiB
Go
package game
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import (
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"errors"
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"fmt"
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)
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// ErrNotFound reports that a game record was requested but does not exist
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// in the store.
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var ErrNotFound = errors.New("game not found")
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// ErrConflict reports that a game mutation could not be applied because the
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// record changed concurrently or failed a compare-and-swap guard.
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var ErrConflict = errors.New("game conflict")
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// ErrInvalidTransition is the sentinel returned when Transition rejects a
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// `(from, to, trigger)` triplet.
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var ErrInvalidTransition = errors.New("invalid game status transition")
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// InvalidTransitionError stores the rejected `(from, to, trigger)` triplet
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// and wraps ErrInvalidTransition so callers can match it with errors.Is.
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type InvalidTransitionError struct {
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// From stores the source status that was attempted to leave.
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From Status
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// To stores the destination status that was attempted to enter.
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To Status
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// Trigger stores the transition trigger that was attempted.
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Trigger Trigger
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}
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// Error reports a human-readable summary of the rejected triplet.
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func (err *InvalidTransitionError) Error() string {
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return fmt.Sprintf(
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"invalid game status transition from %q to %q with trigger %q",
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err.From, err.To, err.Trigger,
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)
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}
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// Unwrap returns ErrInvalidTransition so errors.Is recognizes the sentinel.
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func (err *InvalidTransitionError) Unwrap() error {
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return ErrInvalidTransition
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}
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