X-Git-Url: https://git.lizzy.rs/?a=blobdiff_plain;f=intent.go;h=56900a437ef44a08feb2dcaf5718a830473c0f53;hb=e6b6a718a328e339e022cc05f5c79940cca6dec5;hp=853d8270902be287bd95bb4b67b171d4a5df0509;hpb=e54415863fb1aaa9a12d4a351557667f2d668c30;p=go-anidb.git

diff --git a/intent.go b/intent.go
index 853d827..56900a4 100644
--- a/intent.go
+++ b/intent.go
@@ -9,6 +9,8 @@ type intentStruct struct {
 
 type intentMapStruct struct {
 	sync.Mutex
+	intentLock sync.Mutex // used by the Intent function
+
 	m map[string]*intentStruct
 }
 
@@ -17,6 +19,8 @@ var intentMap = &intentMapStruct{
 }
 
 // Register a channel to be notified when the specified keys are notified.
+// Returns whether the caller was the first to register intent for the given
+// keys.
 //
 // Cache checks should be done after registering intent, since it's possible to
 // register Intent while a Notify is running, and the Notify is done after
@@ -24,11 +28,13 @@ var intentMap = &intentMapStruct{
 func (m *intentMapStruct) Intent(ch chan Cacheable, keys ...cacheKey) bool {
 	key := cachePath(keys...)
 
+	m.intentLock.Lock()
+	defer m.intentLock.Unlock()
+
 	m.Lock()
 	s, ok := m.m[key]
 	if !ok {
 		s = &intentStruct{}
-		m.m[key] = s
 	}
 	m.Unlock()
 
@@ -36,28 +42,109 @@ func (m *intentMapStruct) Intent(ch chan Cacheable, keys ...cacheKey) bool {
 	s.chs = append(s.chs, ch)
 	s.Unlock()
 
+	m.Lock()
+	// key might have been deleted while only the struct itself was locked -- recheck
+	_, ok = m.m[key]
+	m.m[key] = s
+	m.Unlock()
+
 	return ok
 }
 
-// Notify all channels that are listening for the specified keys.
+// Locks the requested keys and return the locked intentStruct.
 //
-// Should be called after setting the cache.
-func (m *intentMapStruct) Notify(v Cacheable, keys ...cacheKey) {
-	key := cachePath(keys...)
-
+// The intentStruct can be directly unlocked, or given to Free to also
+// remove it from the intent map.
+func (m *intentMapStruct) LockIntent(keys ...cacheKey) *intentStruct {
 	m.Lock()
 	defer m.Unlock()
-	s, ok := m.m[key]
+
+	return m._lockIntent(keys...)
+}
+
+func (m *intentMapStruct) _lockIntent(keys ...cacheKey) *intentStruct {
+	s, ok := m.m[cachePath(keys...)]
 	if !ok {
-		return
+		return nil
 	}
 
 	s.Lock()
-	defer s.Unlock()
+	return s
+}
+
+// Removes the given intent from the intent map and unlocks the intentStruct.
+func (m *intentMapStruct) Free(is *intentStruct, keys ...cacheKey) {
+	m.Lock()
+	defer m.Unlock()
+
+	m._free(is, keys...)
+}
 
+func (m *intentMapStruct) _free(is *intentStruct, keys ...cacheKey) {
+	// deletes the key before unlocking, Intent needs to recheck key status
+	delete(m.m, cachePath(keys...))
+	// better than unlocking then deleting -- could delete a "brand new" entry
+	is.Unlock()
+}
+
+// Notifies and closes all channels that are listening for the specified keys;
+// also removes them from the intent map.
+//
+// Should be called after setting the cache.
+func (m *intentMapStruct) NotifyClose(v Cacheable, keys ...cacheKey) {
+	m.Lock()
+	defer m.Unlock()
+
+	is := m._lockIntent(keys...)
+	defer m._free(is, keys...)
+
+	is.NotifyClose(v)
+}
+
+// Closes all channels that are listening for the specified keys
+// and removes them from the intent map.
+func (m *intentMapStruct) Close(keys ...cacheKey) {
+	m.Lock()
+	defer m.Unlock()
+
+	is := m._lockIntent(keys...)
+	defer m._free(is, keys...)
+
+	is.Close()
+}
+
+// Notifies all channels that are listening for the specified keys,
+// but doesn't close or remove them from the intent map.
+func (m *intentMapStruct) Notify(v Cacheable, keys ...cacheKey) {
+	m.Lock()
+	defer m.Unlock()
+
+	is := m._lockIntent(keys...)
+	defer is.Unlock()
+
+	is.Notify(v)
+}
+
+// NOTE: does not lock the stuct
+func (s *intentStruct) Notify(v Cacheable) {
+	for _, ch := range s.chs {
+		ch <- v
+	}
+}
+
+// NOTE: does not lock the struct
+func (s *intentStruct) Close() {
 	for _, ch := range s.chs {
-		go func(c chan Cacheable) { c <- v }(ch)
+		close(ch)
 	}
+	s.chs = nil
+}
 
-	delete(m.m, key)
+// NOTE: does not lock the struct
+func (s *intentStruct) NotifyClose(v Cacheable) {
+	for _, ch := range s.chs {
+		ch <- v
+		close(ch)
+	}
+	s.chs = nil
 }