feat: gitea client

vendor/cloud.google.com/go/auth/grpctransport/pool.go

@@ -0,0 +1,119 @@
+// Copyright 2023 Google LLC
+//
+// 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 grpctransport
+
+import (
+	"context"
+	"fmt"
+	"sync/atomic"
+
+	"google.golang.org/grpc"
+)
+
+// GRPCClientConnPool is an interface that satisfies
+// [google.golang.org/grpc.ClientConnInterface] and has some utility functions
+// that are needed for connection lifecycle when using in a client library. It
+// may be a pool or a single connection. This interface is not intended to, and
+// can't be, implemented by others.
+type GRPCClientConnPool interface {
+	// Connection returns a [google.golang.org/grpc.ClientConn] from the pool.
+	//
+	// ClientConn aren't returned to the pool and should not be closed directly.
+	Connection() *grpc.ClientConn
+
+	// Len returns the number of connections in the pool. It will always return
+	// the same value.
+	Len() int
+
+	// Close closes every ClientConn in the pool. The error returned by Close
+	// may be a single error or multiple errors.
+	Close() error
+
+	grpc.ClientConnInterface
+
+	// private ensure others outside this package can't implement this type
+	private()
+}
+
+// singleConnPool is a special case for a single connection.
+type singleConnPool struct {
+	*grpc.ClientConn
+}
+
+func (p *singleConnPool) Connection() *grpc.ClientConn { return p.ClientConn }
+func (p *singleConnPool) Len() int                     { return 1 }
+func (p *singleConnPool) private()                     {}
+
+type roundRobinConnPool struct {
+	conns []*grpc.ClientConn
+
+	idx uint32 // access via sync/atomic
+}
+
+func (p *roundRobinConnPool) Len() int {
+	return len(p.conns)
+}
+
+func (p *roundRobinConnPool) Connection() *grpc.ClientConn {
+	i := atomic.AddUint32(&p.idx, 1)
+	return p.conns[i%uint32(len(p.conns))]
+}
+
+func (p *roundRobinConnPool) Close() error {
+	var errs multiError
+	for _, conn := range p.conns {
+		if err := conn.Close(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+	if len(errs) == 0 {
+		return nil
+	}
+	return errs
+}
+
+func (p *roundRobinConnPool) Invoke(ctx context.Context, method string, args interface{}, reply interface{}, opts ...grpc.CallOption) error {
+	return p.Connection().Invoke(ctx, method, args, reply, opts...)
+}
+
+func (p *roundRobinConnPool) NewStream(ctx context.Context, desc *grpc.StreamDesc, method string, opts ...grpc.CallOption) (grpc.ClientStream, error) {
+	return p.Connection().NewStream(ctx, desc, method, opts...)
+}
+
+func (p *roundRobinConnPool) private() {}
+
+// multiError represents errors from multiple conns in the group.
+type multiError []error
+
+func (m multiError) Error() string {
+	s, n := "", 0
+	for _, e := range m {
+		if e != nil {
+			if n == 0 {
+				s = e.Error()
+			}
+			n++
+		}
+	}
+	switch n {
+	case 0:
+		return "(0 errors)"
+	case 1:
+		return s
+	case 2:
+		return s + " (and 1 other error)"
+	}
+	return fmt.Sprintf("%s (and %d other errors)", s, n-1)
+}