mutex

type AcquireOpts struct {
	TTL    time.Duration
	Agent  string
	PID    int
	Host   string
	Reason string
	// WaiterID is this caller's queue identity (see Waiter.ID). When set,
	// FIFO fairness lets us take the lease only if we are the fresh queue
	// head, and our queue entry is removed on success.
	WaiterID string
	// Enqueued indicates we have a queue entry that should be removed if
	// the acquire succeeds.
	Enqueued bool
	// Reclaim skips the FIFO queue-head check: use it to re-establish a
	// lease you were actively holding (e.g. `run` re-taking a key that was
	// force-released or pruned out from under an in-flight command). It
	// still refuses a key currently held by a different live holder.
	Reclaim bool
}

type AcquireResult struct {
	Acquired bool
	// Holder is our new lease when Acquired, otherwise the current
	// unexpired holder blocking us (nil if the key is free).
	Holder *Holder
	// Blocker is the fresh queue head ahead of us, when the key is free
	// (or expired) but FIFO order says it is not our turn.
	Blocker *Waiter
}

type CorruptError struct {
	Path string
	Err  error
}

type Holder struct {
	Key        string     `json:"key"`
	Token      string     `json:"token,omitempty"`
	Agent      string     `json:"agent"`
	PID        int        `json:"pid"`
	Host       string     `json:"host"`
	Reason     string     `json:"reason,omitempty"`
	AcquiredAt time.Time  `json:"acquired_at"`
	ExpiresAt  time.Time  `json:"expires_at"`
	RenewedAt  *time.Time `json:"renewed_at,omitempty"`
}

type KeyStatus struct {
	Key string `json:"key"`
	// State is "held", "expired", "free", "corrupt" (holder.json is
	// unparseable) or "unreadable" (an I/O error prevented reading it).
	State   string   `json:"state"`
	Holder  *Holder  `json:"holder,omitempty"`
	Waiters []Waiter `json:"waiters"`
	// Error carries the underlying message when State is "unreadable".
	Error string `json:"error,omitempty"`
}

type NotHolderError struct{ Holder *Holder }

type PruneResult struct {
	ExpiredLeases []string `json:"expired_leases"`
	StaleWaiters  int      `json:"stale_waiters"`
	// Errors holds per-key failures; Prune keeps going past them so one
	// wedged key cannot hide cleanup of all the others.
	Errors []string `json:"errors,omitempty"`
}

type Store struct {
	Root             string
	WaiterStaleAfter time.Duration
	WaiterPIDGrace   time.Duration
	// contains filtered or unexported fields
}

type Waiter struct {
	ID         string    `json:"id"`
	Agent      string    `json:"agent"`
	PID        int       `json:"pid"`
	Host       string    `json:"host"`
	Reason     string    `json:"reason,omitempty"`
	EnqueuedAt time.Time `json:"enqueued_at"`

	// Fresh and LastSeen are computed from the entry's mtime on read; the
	// on-disk "fresh" field is written true and ignored when reading.
	Fresh    bool      `json:"fresh"`
	LastSeen time.Time `json:"last_seen,omitzero"`
}