rebase: bump google.golang.org/grpc from 1.62.1 to 1.63.2

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.62.1 to 1.63.2.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.62.1...v1.63.2)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/google.golang.org/grpc/internal/channelz/channel.go

@@ -0,0 +1,255 @@
+/*
+ *
+ * Copyright 2024 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 channelz
+
+import (
+	"fmt"
+	"sync/atomic"
+
+	"google.golang.org/grpc/connectivity"
+)
+
+// Channel represents a channel within channelz, which includes metrics and
+// internal channelz data, such as channelz id, child list, etc.
+type Channel struct {
+	Entity
+	// ID is the channelz id of this channel.
+	ID int64
+	// RefName is the human readable reference string of this channel.
+	RefName string
+
+	closeCalled bool
+	nestedChans map[int64]string
+	subChans    map[int64]string
+	Parent      *Channel
+	trace       *ChannelTrace
+	// traceRefCount is the number of trace events that reference this channel.
+	// Non-zero traceRefCount means the trace of this channel cannot be deleted.
+	traceRefCount int32
+
+	ChannelMetrics ChannelMetrics
+}
+
+// Implemented to make Channel implement the Identifier interface used for
+// nesting.
+func (c *Channel) channelzIdentifier() {}
+
+func (c *Channel) String() string {
+	if c.Parent == nil {
+		return fmt.Sprintf("Channel #%d", c.ID)
+	}
+	return fmt.Sprintf("%s Channel #%d", c.Parent, c.ID)
+}
+
+func (c *Channel) id() int64 {
+	return c.ID
+}
+
+func (c *Channel) SubChans() map[int64]string {
+	db.mu.RLock()
+	defer db.mu.RUnlock()
+	return copyMap(c.subChans)
+}
+
+func (c *Channel) NestedChans() map[int64]string {
+	db.mu.RLock()
+	defer db.mu.RUnlock()
+	return copyMap(c.nestedChans)
+}
+
+func (c *Channel) Trace() *ChannelTrace {
+	db.mu.RLock()
+	defer db.mu.RUnlock()
+	return c.trace.copy()
+}
+
+type ChannelMetrics struct {
+	// The current connectivity state of the channel.
+	State atomic.Pointer[connectivity.State]
+	// The target this channel originally tried to connect to.  May be absent
+	Target atomic.Pointer[string]
+	// The number of calls started on the channel.
+	CallsStarted atomic.Int64
+	// The number of calls that have completed with an OK status.
+	CallsSucceeded atomic.Int64
+	// The number of calls that have a completed with a non-OK status.
+	CallsFailed atomic.Int64
+	// The last time a call was started on the channel.
+	LastCallStartedTimestamp atomic.Int64
+}
+
+// CopyFrom copies the metrics in o to c.  For testing only.
+func (c *ChannelMetrics) CopyFrom(o *ChannelMetrics) {
+	c.State.Store(o.State.Load())
+	c.Target.Store(o.Target.Load())
+	c.CallsStarted.Store(o.CallsStarted.Load())
+	c.CallsSucceeded.Store(o.CallsSucceeded.Load())
+	c.CallsFailed.Store(o.CallsFailed.Load())
+	c.LastCallStartedTimestamp.Store(o.LastCallStartedTimestamp.Load())
+}
+
+// Equal returns true iff the metrics of c are the same as the metrics of o.
+// For testing only.
+func (c *ChannelMetrics) Equal(o any) bool {
+	oc, ok := o.(*ChannelMetrics)
+	if !ok {
+		return false
+	}
+	if (c.State.Load() == nil) != (oc.State.Load() == nil) {
+		return false
+	}
+	if c.State.Load() != nil && *c.State.Load() != *oc.State.Load() {
+		return false
+	}
+	if (c.Target.Load() == nil) != (oc.Target.Load() == nil) {
+		return false
+	}
+	if c.Target.Load() != nil && *c.Target.Load() != *oc.Target.Load() {
+		return false
+	}
+	return c.CallsStarted.Load() == oc.CallsStarted.Load() &&
+		c.CallsFailed.Load() == oc.CallsFailed.Load() &&
+		c.CallsSucceeded.Load() == oc.CallsSucceeded.Load() &&
+		c.LastCallStartedTimestamp.Load() == oc.LastCallStartedTimestamp.Load()
+}
+
+func strFromPointer(s *string) string {
+	if s == nil {
+		return ""
+	}
+	return *s
+}
+
+func (c *ChannelMetrics) String() string {
+	return fmt.Sprintf("State: %v, Target: %s, CallsStarted: %v, CallsSucceeded: %v, CallsFailed: %v, LastCallStartedTimestamp: %v",
+		c.State.Load(), strFromPointer(c.Target.Load()), c.CallsStarted.Load(), c.CallsSucceeded.Load(), c.CallsFailed.Load(), c.LastCallStartedTimestamp.Load(),
+	)
+}
+
+func NewChannelMetricForTesting(state connectivity.State, target string, started, succeeded, failed, timestamp int64) *ChannelMetrics {
+	c := &ChannelMetrics{}
+	c.State.Store(&state)
+	c.Target.Store(&target)
+	c.CallsStarted.Store(started)
+	c.CallsSucceeded.Store(succeeded)
+	c.CallsFailed.Store(failed)
+	c.LastCallStartedTimestamp.Store(timestamp)
+	return c
+}
+
+func (c *Channel) addChild(id int64, e entry) {
+	switch v := e.(type) {
+	case *SubChannel:
+		c.subChans[id] = v.RefName
+	case *Channel:
+		c.nestedChans[id] = v.RefName
+	default:
+		logger.Errorf("cannot add a child (id = %d) of type %T to a channel", id, e)
+	}
+}
+
+func (c *Channel) deleteChild(id int64) {
+	delete(c.subChans, id)
+	delete(c.nestedChans, id)
+	c.deleteSelfIfReady()
+}
+
+func (c *Channel) triggerDelete() {
+	c.closeCalled = true
+	c.deleteSelfIfReady()
+}
+
+func (c *Channel) getParentID() int64 {
+	if c.Parent == nil {
+		return -1
+	}
+	return c.Parent.ID
+}
+
+// deleteSelfFromTree tries to delete the channel from the channelz entry relation tree, which means
+// deleting the channel reference from its parent's child list.
+//
+// In order for a channel to be deleted from the tree, it must meet the criteria that, removal of the
+// corresponding grpc object has been invoked, and the channel does not have any children left.
+//
+// The returned boolean value indicates whether the channel has been successfully deleted from tree.
+func (c *Channel) deleteSelfFromTree() (deleted bool) {
+	if !c.closeCalled || len(c.subChans)+len(c.nestedChans) != 0 {
+		return false
+	}
+	// not top channel
+	if c.Parent != nil {
+		c.Parent.deleteChild(c.ID)
+	}
+	return true
+}
+
+// deleteSelfFromMap checks whether it is valid to delete the channel from the map, which means
+// deleting the channel from channelz's tracking entirely. Users can no longer use id to query the
+// channel, and its memory will be garbage collected.
+//
+// The trace reference count of the channel must be 0 in order to be deleted from the map. This is
+// specified in the channel tracing gRFC that as long as some other trace has reference to an entity,
+// the trace of the referenced entity must not be deleted. In order to release the resource allocated
+// by grpc, the reference to the grpc object is reset to a dummy object.
+//
+// deleteSelfFromMap must be called after deleteSelfFromTree returns true.
+//
+// It returns a bool to indicate whether the channel can be safely deleted from map.
+func (c *Channel) deleteSelfFromMap() (delete bool) {
+	return c.getTraceRefCount() == 0
+}
+
+// deleteSelfIfReady tries to delete the channel itself from the channelz database.
+// The delete process includes two steps:
+//  1. delete the channel from the entry relation tree, i.e. delete the channel reference from its
+//     parent's child list.
+//  2. delete the channel from the map, i.e. delete the channel entirely from channelz. Lookup by id
+//     will return entry not found error.
+func (c *Channel) deleteSelfIfReady() {
+	if !c.deleteSelfFromTree() {
+		return
+	}
+	if !c.deleteSelfFromMap() {
+		return
+	}
+	db.deleteEntry(c.ID)
+	c.trace.clear()
+}
+
+func (c *Channel) getChannelTrace() *ChannelTrace {
+	return c.trace
+}
+
+func (c *Channel) incrTraceRefCount() {
+	atomic.AddInt32(&c.traceRefCount, 1)
+}
+
+func (c *Channel) decrTraceRefCount() {
+	atomic.AddInt32(&c.traceRefCount, -1)
+}
+
+func (c *Channel) getTraceRefCount() int {
+	i := atomic.LoadInt32(&c.traceRefCount)
+	return int(i)
+}
+
+func (c *Channel) getRefName() string {
+	return c.RefName
+}