Merge pull request #214 from NyaaaWhatsUpDoc/improvement/update-storage-library

add git.iim.gay/grufwub/go-store for storage backend, replacing blob.Storage

1 files changed, 111 insertions, 0 deletions

diff --git a/vendor/git.iim.gay/grufwub/go-nowish/timeout.go b/vendor/git.iim.gay/grufwub/go-nowish/timeout.go
new file mode 100644
index 000000000..15222281a
--- /dev/null
+++ b/vendor/git.iim.gay/grufwub/go-nowish/timeout.go
@@ -0,0 +1,111 @@
+package nowish
+
+import (
+	"errors"
+	"sync/atomic"
+	"time"
+)
+
+// ErrTimeoutStarted is returned if a Timeout interface is attempted to be reused while still in operation
+var ErrTimeoutStarted = errors.New("nowish: timeout already started")
+
+// timeoutState provides a thread-safe timeout state mechanism
+type timeoutState uint32
+
+// start attempts to start the state, must be already reset, returns success
+func (t *timeoutState) start() bool {
+	return atomic.CompareAndSwapUint32((*uint32)(t), 0, 1)
+}
+
+// stop attempts to stop the state, must already be started, returns success
+func (t *timeoutState) stop() bool {
+	return atomic.CompareAndSwapUint32((*uint32)(t), 1, 2)
+}
+
+// reset is fairly self explanatory
+func (t *timeoutState) reset() {
+	atomic.StoreUint32((*uint32)(t), 0)
+}
+
+// Timeout provides a reusable structure for enforcing timeouts with a cancel
+type Timeout interface {
+	// Start starts the timer with supplied timeout. If timeout is reached before
+	// cancel then supplied timeout hook will be called. Error may be called if
+	// Timeout is already running when this function is called
+	Start(time.Duration, func()) error
+
+	// Cancel cancels the currently running timer. If a cancel is achieved, then
+	// this function will return after the timeout goroutine is finished
+	Cancel()
+}
+
+// NewTimeout returns a new Timeout instance
+func NewTimeout() Timeout {
+	t := &timeout{
+		tk: time.NewTicker(time.Minute),
+		ch: make(chan struct{}),
+	}
+	t.tk.Stop() // don't keep it running
+	return t
+}
+
+// timeout is the Timeout implementation that we force
+// initialization on via NewTimeout by unexporting it
+type timeout struct {
+	noCopy noCopy //nolint noCopy because a copy will mess with atomics
+
+	tk *time.Ticker  // tk is the underlying timeout-timer
+	ch chan struct{} // ch is the cancel propagation channel
+	st timeoutState  // st stores the current timeout state (and protects concurrent use)
+}
+
+func (t *timeout) Start(d time.Duration, hook func()) error {
+	// Attempt to acquire start
+	if !t.st.start() {
+		return ErrTimeoutStarted
+	}
+
+	// Start the ticker
+	t.tk.Reset(d)
+
+	go func() {
+		cancelled := false
+
+		select {
+		// Timeout reached
+		case <-t.tk.C:
+			if !t.st.stop() {
+				// cancel was called in the nick of time
+				<-t.ch
+				cancelled = true
+			}
+
+		// Cancel called
+		case <-t.ch:
+			cancelled = true
+		}
+
+		// Stop ticker
+		t.tk.Stop()
+
+		// If timed out call hook
+		if !cancelled {
+			hook()
+		}
+
+		// Finally, reset state
+		t.st.reset()
+	}()
+
+	return nil
+}
+
+func (t *timeout) Cancel() {
+	// Attempt to acquire stop
+	if !t.st.stop() {
+		return
+	}
+
+	// Send a cancel signal
+	t.ch <- struct{}{}
+}