pkg/fileutil: clean up interface, comments

pkg/fileutil/lock.go

@@ -0,0 +1,29 @@
+// Copyright 2016 CoreOS, Inc.
+//
+// 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 fileutil
+
+type Lock interface {
+	// Name returns the name of the file.
+	Name() string
+	// TryLock acquires exclusivity on the lock without blocking.
+	TryLock() error
+	// Lock acquires exclusivity on the lock.
+	Lock() error
+	// Unlock unlocks the lock.
+	Unlock() error
+	// Destroy should be called after Unlock to clean up
+	// the resources.
+	Destroy() error
+}

pkg/fileutil/lock_plan9.go

@@ -25,14 +25,6 @@ var (
 	ErrLocked = errors.New("file already locked")
 )
 
-type Lock interface {
-	Name() string
-	TryLock() error
-	Lock() error
-	Unlock() error
-	Destroy() error
-}
-
 type lock struct {
 	fname string
 	file  *os.File
@@ -42,7 +34,6 @@ func (l *lock) Name() string {
 	return l.fname
 }
 
-// TryLock acquires exclusivity on the lock without blocking
 func (l *lock) TryLock() error {
 	err := os.Chmod(l.fname, syscall.DMEXCL|0600)
 	if err != nil {
@@ -58,7 +49,6 @@ func (l *lock) TryLock() error {
 	return nil
 }
 
-// Lock acquires exclusivity on the lock with blocking
 func (l *lock) Lock() error {
 	err := os.Chmod(l.fname, syscall.DMEXCL|0600)
 	if err != nil {
@@ -75,7 +65,6 @@ func (l *lock) Lock() error {
 	}
 }
 
-// Unlock unlocks the lock
 func (l *lock) Unlock() error {
 	return l.file.Close()
 }

pkg/fileutil/lock_solaris.go

@@ -26,14 +26,6 @@ var (
 	ErrLocked = errors.New("file already locked")
 )
 
-type Lock interface {
-	Name() string
-	TryLock() error
-	Lock() error
-	Unlock() error
-	Destroy() error
-}
-
 type lock struct {
 	fd   int
 	file *os.File
@@ -43,7 +35,6 @@ func (l *lock) Name() string {
 	return l.file.Name()
 }
 
-// TryLock acquires exclusivity on the lock without blocking
 func (l *lock) TryLock() error {
 	var lock syscall.Flock_t
 	lock.Start = 0
@@ -59,7 +50,6 @@ func (l *lock) TryLock() error {
 	return err
 }
 
-// Lock acquires exclusivity on the lock without blocking
 func (l *lock) Lock() error {
 	var lock syscall.Flock_t
 	lock.Start = 0
@@ -70,7 +60,6 @@ func (l *lock) Lock() error {
 	return syscall.FcntlFlock(uintptr(l.fd), syscall.F_SETLK, &lock)
 }
 
-// Unlock unlocks the lock
 func (l *lock) Unlock() error {
 	var lock syscall.Flock_t
 	lock.Start = 0

pkg/fileutil/lock_unix.go

@@ -26,14 +26,6 @@ var (
 	ErrLocked = errors.New("file already locked")
 )
 
-type Lock interface {
-	Name() string
-	TryLock() error
-	Lock() error
-	Unlock() error
-	Destroy() error
-}
-
 type lock struct {
 	fd   int
 	file *os.File
@@ -43,7 +35,6 @@ func (l *lock) Name() string {
 	return l.file.Name()
 }
 
-// TryLock acquires exclusivity on the lock without blocking
 func (l *lock) TryLock() error {
 	err := syscall.Flock(l.fd, syscall.LOCK_EX|syscall.LOCK_NB)
 	if err != nil && err == syscall.EWOULDBLOCK {
@@ -52,12 +43,10 @@ func (l *lock) TryLock() error {
 	return err
 }
 
-// Lock acquires exclusivity on the lock without blocking
 func (l *lock) Lock() error {
 	return syscall.Flock(l.fd, syscall.LOCK_EX)
 }
 
-// Unlock unlocks the lock
 func (l *lock) Unlock() error {
 	return syscall.Flock(l.fd, syscall.LOCK_UN)
 }

pkg/fileutil/lock_windows.go

@@ -25,14 +25,6 @@ var (
 	ErrLocked = errors.New("file already locked")
 )
 
-type Lock interface {
-	Name() string
-	TryLock() error
-	Lock() error
-	Unlock() error
-	Destroy() error
-}
-
 type lock struct {
 	fd   int
 	file *os.File
@@ -42,17 +34,14 @@ func (l *lock) Name() string {
 	return l.file.Name()
 }
 
-// TryLock acquires exclusivity on the lock without blocking
 func (l *lock) TryLock() error {
 	return nil
 }
 
-// Lock acquires exclusivity on the lock without blocking
 func (l *lock) Lock() error {
 	return nil
 }
 
-// Unlock unlocks the lock
 func (l *lock) Unlock() error {
 	return nil
 }