LogDog: Add Butler stream server package.

client/internal/logdog/butler/streamserver/npipe_posix.go

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd
+
+package streamserver
+
+import (
+        "fmt"
+        "net"
+        "os"
+
+        log "github.com/luci/luci-go/common/logging"
+        "golang.org/x/net/context"
+)
+
+type namedPipeServer struct {
+        namedPipeServerBase
+
+        path string // The path on the filesystem of the UNIX domain named socket
+}
+
+func (s *namedPipeServer) GoString() string {
+        return fmt.Sprintf("namedPipeServer[%s]", s.path)
+}
+
+// Wrapper around the "unix"-type Listener that cleans up the named pipe on
+// creation and 'Close()'
+type selfCleaningUNIXListener struct {
+        path     string
+        listener net.Listener
+}
+
+// NewNamedPipeServer instantiates a new POSIX named pipe server instance.
+func NewNamedPipeServer(ctx context.Context, path string) StreamServer {
+        s := &namedPipeServer{
+                path: path,
+        }
+        s.initBase(ctx)
+        return s
+}
+
+// OS-specific override to create a UNIX named socket listener
+func (s *namedPipeServer) createListener() (net.Listener, error) {
+        log.Fields{
+                "path": s.path,
+        }.Infof(s.ctx, "Creating POSIX server socket Listener.")
+        return newSelfCleaningUNIXListener(s.path)
+}
+
+//
+// selfCleaningUNIXListener
+//
+
+func newSelfCleaningUNIXListener(path string) (net.Listener, error) {
+        // Cleanup any previous entry
+        os.Remove(path)
+
+        // Create a UNIX listener
+        listener, err := net.Listen("unix", path)
+        if err != nil {
+                return nil, err
+        }
+
+        l := selfCleaningUNIXListener{
+                path:     path,
+                listener: listener,
+        }
+        return &l, nil
+}
+
+// Implements net.Listner.Accept
+func (l *selfCleaningUNIXListener) Accept() (c net.Conn, err error) {
+        return l.listener.Accept()
+}
+
+// Implements net.Listener.Close
+func (l *selfCleaningUNIXListener) Close() error {
+        if err := l.listener.Close(); err != nil {
+                return err
+        }
+
+        os.Remove(l.path)
+        return nil
+}
+
+// Implements net.Listener.Addr
+func (l *selfCleaningUNIXListener) Addr() net.Addr {
+        return l.listener.Addr()
+}