chore: vendor

vendor/google.golang.org/grpc/internal/grpcsync/callback_serializer.go

@@ -0,0 +1,100 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpcsync
+
+import (
+	"context"
+
+	"google.golang.org/grpc/internal/buffer"
+)
+
+// CallbackSerializer provides a mechanism to schedule callbacks in a
+// synchronized manner. It provides a FIFO guarantee on the order of execution
+// of scheduled callbacks. New callbacks can be scheduled by invoking the
+// Schedule() method.
+//
+// This type is safe for concurrent access.
+type CallbackSerializer struct {
+	// done is closed once the serializer is shut down completely, i.e all
+	// scheduled callbacks are executed and the serializer has deallocated all
+	// its resources.
+	done chan struct{}
+
+	callbacks *buffer.Unbounded
+}
+
+// NewCallbackSerializer returns a new CallbackSerializer instance. The provided
+// context will be passed to the scheduled callbacks. Users should cancel the
+// provided context to shutdown the CallbackSerializer. It is guaranteed that no
+// callbacks will be added once this context is canceled, and any pending un-run
+// callbacks will be executed before the serializer is shut down.
+func NewCallbackSerializer(ctx context.Context) *CallbackSerializer {
+	cs := &CallbackSerializer{
+		done:      make(chan struct{}),
+		callbacks: buffer.NewUnbounded(),
+	}
+	go cs.run(ctx)
+	return cs
+}
+
+// Schedule adds a callback to be scheduled after existing callbacks are run.
+//
+// Callbacks are expected to honor the context when performing any blocking
+// operations, and should return early when the context is canceled.
+//
+// Return value indicates if the callback was successfully added to the list of
+// callbacks to be executed by the serializer. It is not possible to add
+// callbacks once the context passed to NewCallbackSerializer is cancelled.
+func (cs *CallbackSerializer) Schedule(f func(ctx context.Context)) bool {
+	return cs.callbacks.Put(f) == nil
+}
+
+func (cs *CallbackSerializer) run(ctx context.Context) {
+	defer close(cs.done)
+
+	// TODO: when Go 1.21 is the oldest supported version, this loop and Close
+	// can be replaced with:
+	//
+	// context.AfterFunc(ctx, cs.callbacks.Close)
+	for ctx.Err() == nil {
+		select {
+		case <-ctx.Done():
+			// Do nothing here. Next iteration of the for loop will not happen,
+			// since ctx.Err() would be non-nil.
+		case cb := <-cs.callbacks.Get():
+			cs.callbacks.Load()
+			cb.(func(context.Context))(ctx)
+		}
+	}
+
+	// Close the buffer to prevent new callbacks from being added.
+	cs.callbacks.Close()
+
+	// Run all pending callbacks.
+	for cb := range cs.callbacks.Get() {
+		cs.callbacks.Load()
+		cb.(func(context.Context))(ctx)
+	}
+}
+
+// Done returns a channel that is closed after the context passed to
+// NewCallbackSerializer is canceled and all callbacks have been executed.
+func (cs *CallbackSerializer) Done() <-chan struct{} {
+	return cs.done
+}

vendor/google.golang.org/grpc/internal/grpcsync/event.go

@@ -0,0 +1,61 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+// Package grpcsync implements additional synchronization primitives built upon
+// the sync package.
+package grpcsync
+
+import (
+	"sync"
+	"sync/atomic"
+)
+
+// Event represents a one-time event that may occur in the future.
+type Event struct {
+	fired int32
+	c     chan struct{}
+	o     sync.Once
+}
+
+// Fire causes e to complete.  It is safe to call multiple times, and
+// concurrently.  It returns true iff this call to Fire caused the signaling
+// channel returned by Done to close.
+func (e *Event) Fire() bool {
+	ret := false
+	e.o.Do(func() {
+		atomic.StoreInt32(&e.fired, 1)
+		close(e.c)
+		ret = true
+	})
+	return ret
+}
+
+// Done returns a channel that will be closed when Fire is called.
+func (e *Event) Done() <-chan struct{} {
+	return e.c
+}
+
+// HasFired returns true if Fire has been called.
+func (e *Event) HasFired() bool {
+	return atomic.LoadInt32(&e.fired) == 1
+}
+
+// NewEvent returns a new, ready-to-use Event.
+func NewEvent() *Event {
+	return &Event{c: make(chan struct{})}
+}

vendor/google.golang.org/grpc/internal/grpcsync/oncefunc.go

@@ -0,0 +1,32 @@
+/*
+ *
+ * Copyright 2022 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpcsync
+
+import (
+	"sync"
+)
+
+// OnceFunc returns a function wrapping f which ensures f is only executed
+// once even if the returned function is executed multiple times.
+func OnceFunc(f func()) func() {
+	var once sync.Once
+	return func() {
+		once.Do(f)
+	}
+}

vendor/google.golang.org/grpc/internal/grpcsync/pubsub.go

@@ -0,0 +1,121 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpcsync
+
+import (
+	"context"
+	"sync"
+)
+
+// Subscriber represents an entity that is subscribed to messages published on
+// a PubSub. It wraps the callback to be invoked by the PubSub when a new
+// message is published.
+type Subscriber interface {
+	// OnMessage is invoked when a new message is published. Implementations
+	// must not block in this method.
+	OnMessage(msg any)
+}
+
+// PubSub is a simple one-to-many publish-subscribe system that supports
+// messages of arbitrary type. It guarantees that messages are delivered in
+// the same order in which they were published.
+//
+// Publisher invokes the Publish() method to publish new messages, while
+// subscribers interested in receiving these messages register a callback
+// via the Subscribe() method.
+//
+// Once a PubSub is stopped, no more messages can be published, but any pending
+// published messages will be delivered to the subscribers.  Done may be used
+// to determine when all published messages have been delivered.
+type PubSub struct {
+	cs *CallbackSerializer
+
+	// Access to the below fields are guarded by this mutex.
+	mu          sync.Mutex
+	msg         any
+	subscribers map[Subscriber]bool
+}
+
+// NewPubSub returns a new PubSub instance.  Users should cancel the
+// provided context to shutdown the PubSub.
+func NewPubSub(ctx context.Context) *PubSub {
+	return &PubSub{
+		cs:          NewCallbackSerializer(ctx),
+		subscribers: map[Subscriber]bool{},
+	}
+}
+
+// Subscribe registers the provided Subscriber to the PubSub.
+//
+// If the PubSub contains a previously published message, the Subscriber's
+// OnMessage() callback will be invoked asynchronously with the existing
+// message to begin with, and subsequently for every newly published message.
+//
+// The caller is responsible for invoking the returned cancel function to
+// unsubscribe itself from the PubSub.
+func (ps *PubSub) Subscribe(sub Subscriber) (cancel func()) {
+	ps.mu.Lock()
+	defer ps.mu.Unlock()
+
+	ps.subscribers[sub] = true
+
+	if ps.msg != nil {
+		msg := ps.msg
+		ps.cs.Schedule(func(context.Context) {
+			ps.mu.Lock()
+			defer ps.mu.Unlock()
+			if !ps.subscribers[sub] {
+				return
+			}
+			sub.OnMessage(msg)
+		})
+	}
+
+	return func() {
+		ps.mu.Lock()
+		defer ps.mu.Unlock()
+		delete(ps.subscribers, sub)
+	}
+}
+
+// Publish publishes the provided message to the PubSub, and invokes
+// callbacks registered by subscribers asynchronously.
+func (ps *PubSub) Publish(msg any) {
+	ps.mu.Lock()
+	defer ps.mu.Unlock()
+
+	ps.msg = msg
+	for sub := range ps.subscribers {
+		s := sub
+		ps.cs.Schedule(func(context.Context) {
+			ps.mu.Lock()
+			defer ps.mu.Unlock()
+			if !ps.subscribers[s] {
+				return
+			}
+			s.OnMessage(msg)
+		})
+	}
+}
+
+// Done returns a channel that is closed after the context passed to NewPubSub
+// is canceled and all updates have been sent to subscribers.
+func (ps *PubSub) Done() <-chan struct{} {
+	return ps.cs.Done()
+}