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

Signed-off-by: kim (grufwub) <grufwub@gmail.com>

vendor/git.iim.gay/grufwub/go-mutexes/mutex_safe.go

@@ -0,0 +1,39 @@
+package mutexes
+
+import "sync"
+
+// WithSafety wrapps the supplied Mutex to protect unlock fns
+// from being called multiple times
+func WithSafety(mu Mutex) Mutex {
+	return &safeMutex{mu: mu}
+}
+
+// WithSafetyRW wrapps the supplied RWMutex to protect unlock
+// fns from being called multiple times
+func WithSafetyRW(mu RWMutex) RWMutex {
+	return &safeRWMutex{mu: mu}
+}
+
+// safeMutex simply wraps a Mutex to add multi-unlock safety
+type safeMutex struct{ mu Mutex }
+
+func (mu *safeMutex) Lock() func() {
+	unlock := mu.mu.Lock()
+	once := sync.Once{}
+	return func() { once.Do(unlock) }
+}
+
+// safeRWMutex simply wraps a RWMutex to add multi-unlock safety
+type safeRWMutex struct{ mu RWMutex }
+
+func (mu *safeRWMutex) Lock() func() {
+	unlock := mu.mu.Lock()
+	once := sync.Once{}
+	return func() { once.Do(unlock) }
+}
+
+func (mu *safeRWMutex) RLock() func() {
+	unlock := mu.mu.RLock()
+	once := sync.Once{}
+	return func() { once.Do(unlock) }
+}