Mutex style change.

For structs protected by a single mutex, embed the mutex for more
concise usage.

Also use a sync.Mutex directly, rather than a pointer, to avoid the
need for initialization (because a Mutex's zero-value is valid and
ready to be used).

buildfile_test.go

@@ -3,7 +3,6 @@ package docker
 import (
 	"fmt"
 	"io/ioutil"
-	"sync"
 	"testing"
 )
 
@@ -105,7 +104,6 @@ func TestBuild(t *testing.T) {
 
 		srv := &Server{
 			runtime:     runtime,
-			lock:        &sync.Mutex{},
 			pullingPool: make(map[string]struct{}),
 			pushingPool: make(map[string]struct{}),
 		}

container.go

@@ -466,8 +466,8 @@ func (container *Container) Attach(stdin io.ReadCloser, stdinCloser io.Closer, s
 }
 
 func (container *Container) Start(hostConfig *HostConfig) error {
-	container.State.lock()
+	container.State.Lock()
-	defer container.State.unlock()
+	defer container.State.Unlock()
 
 	if container.State.Running {
 		return fmt.Errorf("The container %s is already running.", container.ID)
@@ -821,8 +821,8 @@ func (container *Container) kill() error {
 }
 
 func (container *Container) Kill() error {
-	container.State.lock()
+	container.State.Lock()
-	defer container.State.unlock()
+	defer container.State.Unlock()
 	if !container.State.Running {
 		return nil
 	}
@@ -830,8 +830,8 @@ func (container *Container) Kill() error {
 }
 
 func (container *Container) Stop(seconds int) error {
-	container.State.lock()
+	container.State.Lock()
-	defer container.State.unlock()
+	defer container.State.Unlock()
 	if !container.State.Running {
 		return nil
 	}

network.go

@@ -301,9 +301,9 @@ func newPortMapper() (*PortMapper, error) {
 
 // Port allocator: Atomatically allocate and release networking ports
 type PortAllocator struct {
+	sync.Mutex
 	inUse    map[int]struct{}
 	fountain chan (int)
-	lock     sync.Mutex
 }
 
 func (alloc *PortAllocator) runFountain() {
@@ -317,9 +317,9 @@ func (alloc *PortAllocator) runFountain() {
 // FIXME: Release can no longer fail, change its prototype to reflect that.
 func (alloc *PortAllocator) Release(port int) error {
 	utils.Debugf("Releasing %d", port)
-	alloc.lock.Lock()
+	alloc.Lock()
 	delete(alloc.inUse, port)
-	alloc.lock.Unlock()
+	alloc.Unlock()
 	return nil
 }
 
@@ -334,8 +334,8 @@ func (alloc *PortAllocator) Acquire(port int) (int, error) {
 		}
 		return -1, fmt.Errorf("Port generator ended unexpectedly")
 	}
-	alloc.lock.Lock()
+	alloc.Lock()
-	defer alloc.lock.Unlock()
+	defer alloc.Unlock()
 	if _, inUse := alloc.inUse[port]; inUse {
 		return -1, fmt.Errorf("Port already in use: %d", port)
 	}

runtime.go

@@ -108,9 +108,6 @@ func (runtime *Runtime) Register(container *Container) error {
 	// init the wait lock
 	container.waitLock = make(chan struct{})
 
-	// Even if not running, we init the lock (prevents races in start/stop/kill)
-	container.State.initLock()
-
 	container.runtime = runtime
 
 	// Attach to stdout and stderr

runtime_test.go

@@ -89,7 +89,6 @@ func init() {
 	srv := &Server{
 		runtime:     runtime,
 		enableCors:  false,
-		lock:        &sync.Mutex{},
 		pullingPool: make(map[string]struct{}),
 		pushingPool: make(map[string]struct{}),
 	}

server.go

@@ -450,8 +450,8 @@ func (srv *Server) pullRepository(r *registry.Registry, out io.Writer, local, re
 }
 
 func (srv *Server) poolAdd(kind, key string) error {
-	srv.lock.Lock()
+	srv.Lock()
-	defer srv.lock.Unlock()
+	defer srv.Unlock()
 
 	if _, exists := srv.pullingPool[key]; exists {
 		return fmt.Errorf("%s %s is already in progress", key, kind)
@@ -1119,7 +1119,6 @@ func NewServer(flGraphPath string, autoRestart, enableCors bool, dns ListOpts) (
 	srv := &Server{
 		runtime:     runtime,
 		enableCors:  enableCors,
-		lock:        &sync.Mutex{},
 		pullingPool: make(map[string]struct{}),
 		pushingPool: make(map[string]struct{}),
 	}
@@ -1128,9 +1127,9 @@ func NewServer(flGraphPath string, autoRestart, enableCors bool, dns ListOpts) (
 }
 
 type Server struct {
+	sync.Mutex
 	runtime     *Runtime
 	enableCors  bool
-	lock        *sync.Mutex
 	pullingPool map[string]struct{}
 	pushingPool map[string]struct{}
 }

state.go

@@ -8,11 +8,11 @@ import (
 )
 
 type State struct {
+	sync.Mutex
 	Running   bool
 	Pid       int
 	ExitCode  int
 	StartedAt time.Time
-	l         *sync.Mutex
 	Ghost     bool
 }
 
@@ -39,15 +39,3 @@ func (s *State) setStopped(exitCode int) {
 	s.Pid = 0
 	s.ExitCode = exitCode
 }
-
-func (s *State) initLock() {
-	s.l = &sync.Mutex{}
-}
-
-func (s *State) lock() {
-	s.l.Lock()
-}
-
-func (s *State) unlock() {
-	s.l.Unlock()
-}

utils/utils.go

@@ -188,10 +188,10 @@ func NopWriteCloser(w io.Writer) io.WriteCloser {
 }
 
 type bufReader struct {
+	sync.Mutex
 	buf    *bytes.Buffer
 	reader io.Reader
 	err    error
-	l      sync.Mutex
 	wait   sync.Cond
 }
 
@@ -200,7 +200,7 @@ func NewBufReader(r io.Reader) *bufReader {
 		buf:    &bytes.Buffer{},
 		reader: r,
 	}
-	reader.wait.L = &reader.l
+	reader.wait.L = &reader.Mutex
 	go reader.drain()
 	return reader
 }
@@ -209,14 +209,14 @@ func (r *bufReader) drain() {
 	buf := make([]byte, 1024)
 	for {
 		n, err := r.reader.Read(buf)
-		r.l.Lock()
+		r.Lock()
 		if err != nil {
 			r.err = err
 		} else {
 			r.buf.Write(buf[0:n])
 		}
 		r.wait.Signal()
-		r.l.Unlock()
+		r.Unlock()
 		if err != nil {
 			break
 		}
@@ -224,8 +224,8 @@ func (r *bufReader) drain() {
 }
 
 func (r *bufReader) Read(p []byte) (n int, err error) {
-	r.l.Lock()
+	r.Lock()
-	defer r.l.Unlock()
+	defer r.Unlock()
 	for {
 		n, err = r.buf.Read(p)
 		if n > 0 {
@@ -247,27 +247,27 @@ func (r *bufReader) Close() error {
 }
 
 type WriteBroadcaster struct {
-	mu      sync.Mutex
+	sync.Mutex
 	writers map[io.WriteCloser]struct{}
 }
 
 func (w *WriteBroadcaster) AddWriter(writer io.WriteCloser) {
-	w.mu.Lock()
+	w.Lock()
 	w.writers[writer] = struct{}{}
-	w.mu.Unlock()
+	w.Unlock()
 }
 
 // FIXME: Is that function used?
 // FIXME: This relies on the concrete writer type used having equality operator
 func (w *WriteBroadcaster) RemoveWriter(writer io.WriteCloser) {
-	w.mu.Lock()
+	w.Lock()
 	delete(w.writers, writer)
-	w.mu.Unlock()
+	w.Unlock()
 }
 
 func (w *WriteBroadcaster) Write(p []byte) (n int, err error) {
-	w.mu.Lock()
+	w.Lock()
-	defer w.mu.Unlock()
+	defer w.Unlock()
 	for writer := range w.writers {
 		if n, err := writer.Write(p); err != nil || n != len(p) {
 			// On error, evict the writer
@@ -278,8 +278,8 @@ func (w *WriteBroadcaster) Write(p []byte) (n int, err error) {
 }
 
 func (w *WriteBroadcaster) CloseWriters() error {
-	w.mu.Lock()
+	w.Lock()
-	defer w.mu.Unlock()
+	defer w.Unlock()
 	for writer := range w.writers {
 		writer.Close()
 	}