From 44b9cb77ec1cffdb8da42ced29b2a4b96fbf00e6 Mon Sep 17 00:00:00 2001 From: John Date: Thu, 10 May 2018 12:04:41 +0800 Subject: [PATCH] =?UTF-8?q?gflock=E5=BC=80=E5=8F=91=E4=B8=AD?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- g/os/gflock/internals/flock/LICENSE | 27 ++++ g/os/gflock/internals/flock/flock.go | 109 +++++++++++++ g/os/gflock/internals/flock/flock_unix.go | 159 +++++++++++++++++++ g/os/gflock/internals/flock/flock_winapi.go | 76 +++++++++ g/os/gflock/internals/flock/flock_windows.go | 140 ++++++++++++++++ geg/os/gflock/gflock.go | 8 +- 6 files changed, 515 insertions(+), 4 deletions(-) create mode 100644 g/os/gflock/internals/flock/LICENSE create mode 100644 g/os/gflock/internals/flock/flock.go create mode 100644 g/os/gflock/internals/flock/flock_unix.go create mode 100644 g/os/gflock/internals/flock/flock_winapi.go create mode 100644 g/os/gflock/internals/flock/flock_windows.go diff --git a/g/os/gflock/internals/flock/LICENSE b/g/os/gflock/internals/flock/LICENSE new file mode 100644 index 000000000..aff7d358e --- /dev/null +++ b/g/os/gflock/internals/flock/LICENSE @@ -0,0 +1,27 @@ +Copyright (c) 2015, Tim Heckman +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + +* Redistributions of source code must retain the above copyright notice, this + list of conditions and the following disclaimer. + +* Redistributions in binary form must reproduce the above copyright notice, + this list of conditions and the following disclaimer in the documentation + and/or other materials provided with the distribution. + +* Neither the name of linode-netint nor the names of its + contributors may be used to endorse or promote products derived from + this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" +AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE +DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE +FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR +SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, +OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/g/os/gflock/internals/flock/flock.go b/g/os/gflock/internals/flock/flock.go new file mode 100644 index 000000000..d04059748 --- /dev/null +++ b/g/os/gflock/internals/flock/flock.go @@ -0,0 +1,109 @@ +// From & Thanks: https://github.com/theckman/go-flock +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +// Package flock implements a thread-safe sync.Locker interface for file locking. +// It also includes a non-blocking TryLock() function to allow locking +// without blocking execution. +// +// Package flock is released under the BSD 3-Clause License. See the LICENSE file +// for more details. +// +// While using this library, remember that the locking behaviors are not +// guaranteed to be the same on each platform. For example, some UNIX-like +// operating systems will transparently convert a shared lock to an exclusive +// lock. If you Unlock() the flock from a location where you believe that you +// have the shared lock, you may accidently drop the exclusive lock. +package flock + +import ( + "context" + "os" + "sync" + "time" +) + +// Flock is the struct type to handle file locking. All fields are unexported, +// with access to some of the fields provided by getter methods (Path() and Locked()). +type Flock struct { + mu sync.RWMutex // 用于接口层的阻塞互斥锁 + path string + m sync.RWMutex + fh *os.File + l bool + r bool +} + +// NewFlock is a function to return a new instance of *Flock. The only parameter +// it takes is the path to the desired lockfile. +func NewFlock(path string) *Flock { + return &Flock{path: path} +} + +// Path is a function to return the path as provided in NewFlock(). +func (f *Flock) Path() string { + return f.path +} + +// Locked is a function to return the current lock state (locked: true, unlocked: false). +func (f *Flock) Locked() bool { + f.m.RLock() + defer f.m.RUnlock() + return f.l +} + +// RLocked is a function to return the current read lock state (locked: true, unlocked: false). +func (f *Flock) RLocked() bool { + f.m.RLock() + defer f.m.RUnlock() + return f.r +} + +func (f *Flock) String() string { + return f.path +} + +// TryLockContext repeatedly tries to take an exclusive lock until one of the +// conditions is met: TryLock succeeds, TryLock fails with error, or Context +// Done channel is closed. +func (f *Flock) TryLockContext(ctx context.Context, retryDelay time.Duration) (bool, error) { + return tryCtx(f.TryLock, ctx, retryDelay) +} + +// TryRLockContext repeatedly tries to take a shared lock until one of the +// conditions is met: TryRLock succeeds, TryRLock fails with error, or Context +// Done channel is closed. +func (f *Flock) TryRLockContext(ctx context.Context, retryDelay time.Duration) (bool, error) { + return tryCtx(f.TryRLock, ctx, retryDelay) +} + +func tryCtx(fn func() (bool, error), ctx context.Context, retryDelay time.Duration) (bool, error) { + if ctx.Err() != nil { + return false, ctx.Err() + } + for { + if ok, err := fn(); ok || err != nil { + return ok, err + } + select { + case <-ctx.Done(): + return false, ctx.Err() + case <-time.After(retryDelay): + // try again + } + } +} + +func (f *Flock) setFh() error { + // open a new os.File instance + // create it if it doesn't exist, and open the file read-only. + fh, err := os.OpenFile(f.path, os.O_CREATE|os.O_RDONLY, os.FileMode(0600)) + if err != nil { + return err + } + + // set the filehandle on the struct + f.fh = fh + return nil +} diff --git a/g/os/gflock/internals/flock/flock_unix.go b/g/os/gflock/internals/flock/flock_unix.go new file mode 100644 index 000000000..8aa896f80 --- /dev/null +++ b/g/os/gflock/internals/flock/flock_unix.go @@ -0,0 +1,159 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +// +build !windows + +package flock + +import ( + "syscall" +) + +// Lock is a blocking call to try and take an exclusive file lock. It will wait +// until it is able to obtain the exclusive file lock. It's recommended that +// TryLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already exclusive-locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +// +// If the *Flock has a shared lock (RLock), this may transparently replace the +// shared lock with an exclusive lock on some UNIX-like operating systems. Be +// careful when using exclusive locks in conjunction with shared locks +// (RLock()), because calling Unlock() may accidentally release the exclusive +// lock that was once a shared lock. +func (f *Flock) Lock() error { + f.mu.Lock() + err := f.lock(&f.l, syscall.LOCK_EX) + if err != nil { + f.mu.Unlock() + return err + } + return nil +} + +// RLock is a blocking call to try and take a ahred file lock. It will wait +// until it is able to obtain the shared file lock. It's recommended that +// TryRLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already shared-locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) RLock() error { + f.mu.RLock() + err := f.lock(&f.r, syscall.LOCK_SH) + if err != nil { + f.mu.RUnlock() + return err + } + return nil +} + +func (f *Flock) lock(locked *bool, flag int) error { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return err + } + } + + if err := syscall.Flock(int(f.fh.Fd()), flag); err != nil { + return err + } + + *locked = true + return nil +} + +// Unlock is a function to unlock the file. This file takes a RW-mutex lock, so +// while it is running the Locked() and RLocked() functions will be blocked. +// +// This function short-circuits if we are unlocked already. If not, it calls +// syscall.LOCK_UN on the file and closes the file descriptor. It does not +// remove the file from disk. It's up to your application to do. +// +// Please note, if your shared lock became an exclusive lock this may +// unintentionally drop the exclusive lock if called by the consumer that +// believes they have a shared lock. Please see Lock() for more details. +func (f *Flock) Unlock() error { + f.m.Lock() + defer f.m.Unlock() + + // if we aren't locked or if the lockfile instance is nil + // just return a nil error because we are unlocked + if (!f.l && !f.r) || f.fh == nil { + return nil + } + + // mark the file as unlocked + if err := syscall.Flock(int(f.fh.Fd()), syscall.LOCK_UN); err != nil { + return err + } + + f.fh.Close() + + f.l = false + f.r = false + f.fh = nil + + f.mu.Unlock() + return nil +} + +// TryLock is the preferred function for taking an exclusive file lock. This +// function takes an RW-mutex lock before it tries to lock the file, so there is +// the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the exclusive +// file lock, the function will return false instead of waiting for the lock. If +// we get the lock, we also set the *Flock instance as being exclusive-locked. +func (f *Flock) TryLock() (bool, error) { + return f.try(&f.l, syscall.LOCK_EX) +} + +// TryRLock is the preferred function for taking a shared file lock. This +// function takes an RW-mutex lock before it tries to lock the file, so there is +// the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the shared file +// lock, the function will return false instead of waiting for the lock. If we +// get the lock, we also set the *Flock instance as being share-locked. +func (f *Flock) TryRLock() (bool, error) { + return f.try(&f.r, syscall.LOCK_SH) +} + +func (f *Flock) try(locked *bool, flag int) (bool, error) { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return true, nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return false, err + } + } + + err := syscall.Flock(int(f.fh.Fd()), flag|syscall.LOCK_NB) + + switch err { + case syscall.EWOULDBLOCK: + return false, nil + case nil: + *locked = true + return true, nil + } + + return false, err +} diff --git a/g/os/gflock/internals/flock/flock_winapi.go b/g/os/gflock/internals/flock/flock_winapi.go new file mode 100644 index 000000000..fe405a255 --- /dev/null +++ b/g/os/gflock/internals/flock/flock_winapi.go @@ -0,0 +1,76 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +// +build windows + +package flock + +import ( + "syscall" + "unsafe" +) + +var ( + kernel32, _ = syscall.LoadLibrary("kernel32.dll") + procLockFileEx, _ = syscall.GetProcAddress(kernel32, "LockFileEx") + procUnlockFileEx, _ = syscall.GetProcAddress(kernel32, "UnlockFileEx") +) + +const ( + winLockfileFailImmediately = 0x00000001 + winLockfileExclusiveLock = 0x00000002 + winLockfileSharedLock = 0x00000000 +) + +// Use of 0x00000000 for the shared lock is a guess based on some the MS Windows +// `LockFileEX` docs, which document the `LOCKFILE_EXCLUSIVE_LOCK` flag as: +// +// > The function requests an exclusive lock. Otherwise, it requests a shared +// > lock. +// +// https://msdn.microsoft.com/en-us/library/windows/desktop/aa365203(v=vs.85).aspx + +func lockFileEx(handle syscall.Handle, flags uint32, reserved uint32, numberOfBytesToLockLow uint32, numberOfBytesToLockHigh uint32, offset *syscall.Overlapped) (bool, syscall.Errno) { + r1, _, errNo := syscall.Syscall6( + uintptr(procLockFileEx), + 6, + uintptr(handle), + uintptr(flags), + uintptr(reserved), + uintptr(numberOfBytesToLockLow), + uintptr(numberOfBytesToLockHigh), + uintptr(unsafe.Pointer(offset))) + + if r1 != 1 { + if errNo == 0 { + return false, syscall.EINVAL + } + + return false, errNo + } + + return true, 0 +} + +func unlockFileEx(handle syscall.Handle, reserved uint32, numberOfBytesToLockLow uint32, numberOfBytesToLockHigh uint32, offset *syscall.Overlapped) (bool, syscall.Errno) { + r1, _, errNo := syscall.Syscall6( + uintptr(procUnlockFileEx), + 5, + uintptr(handle), + uintptr(reserved), + uintptr(numberOfBytesToLockLow), + uintptr(numberOfBytesToLockHigh), + uintptr(unsafe.Pointer(offset)), + 0) + + if r1 != 1 { + if errNo == 0 { + return false, syscall.EINVAL + } + + return false, errNo + } + + return true, 0 +} diff --git a/g/os/gflock/internals/flock/flock_windows.go b/g/os/gflock/internals/flock/flock_windows.go new file mode 100644 index 000000000..a0103f6da --- /dev/null +++ b/g/os/gflock/internals/flock/flock_windows.go @@ -0,0 +1,140 @@ +// Copyright 2015 Tim Heckman. All rights reserved. +// Use of this source code is governed by the BSD 3-Clause +// license that can be found in the LICENSE file. + +package flock + +import ( + "syscall" +) + +// ErrorLockViolation is the error code returned from the Windows syscall when a +// lock would block and you ask to fail immediately. +const ErrorLockViolation syscall.Errno = 0x21 // 33 + +// Lock is a blocking call to try and take an exclusive file lock. It will wait +// until it is able to obtain the exclusive file lock. It's recommended that +// TryLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) Lock() error { + return f.lock(&f.l, winLockfileExclusiveLock) +} + +// RLock is a blocking call to try and take a sahred file lock. It will wait +// until it is able to obtain the shared file lock. It's recommended that +// TryRLock() be used over this function. This function may block the ability to +// query the current Locked() or RLocked() status due to a RW-mutex lock. +// +// If we are already locked, this function short-circuits and returns +// immediately assuming it can take the mutex lock. +func (f *Flock) RLock() error { + return f.lock(&f.r, winLockfileSharedLock) +} + +func (f *Flock) lock(locked *bool, flag uint32) error { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return err + } + } + + if _, errNo := lockFileEx(syscall.Handle(f.fh.Fd()), flag, 0, 1, 0, &syscall.Overlapped{}); errNo > 0 { + return errNo + } + + *locked = true + return nil +} + +// Unlock is a function to unlock the file. This file takes a RW-mutex lock, so +// while it is running the Locked() and RLocked() functions will be blocked. +// +// This function short-circuits if we are unlocked already. If not, it calls +// UnlockFileEx() on the file and closes the file descriptor. It does not remove +// the file from disk. It's up to your application to do. +func (f *Flock) Unlock() error { + f.m.Lock() + defer f.m.Unlock() + + // if we aren't locked or if the lockfile instance is nil + // just return a nil error because we are unlocked + if (!f.l && !f.r) || f.fh == nil { + return nil + } + + // mark the file as unlocked + if _, errNo := unlockFileEx(syscall.Handle(f.fh.Fd()), 0, 1, 0, &syscall.Overlapped{}); errNo > 0 { + return errNo + } + + f.fh.Close() + + f.l = false + f.r = false + f.fh = nil + + return nil +} + +// TryLock is the preferred function for taking an exlusive file lock. This +// function does take a RW-mutex lock before it tries to lock the file, so there +// is the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the exclusive +// file lock, the function will return false instead of waiting for the lock. If +// we get the lock, we also set the *Flock instance as being exclusive-locked. +func (f *Flock) TryLock() (bool, error) { + return f.try(&f.l, winLockfileExclusiveLock) +} + +// TryRLock is the preferred function for taking a shared file lock. This +// function does take a RW-mutex lock before it tries to lock the file, so there +// is the possibility that this function may block for a short time if another +// goroutine is trying to take any action. +// +// The actual file lock is non-blocking. If we are unable to get the shared file +// lock, the function will return false instead of waiting for the lock. If we +// get the lock, we also set the *Flock instance as being shared-locked. +func (f *Flock) TryRLock() (bool, error) { + return f.try(&f.r, winLockfileSharedLock) +} + +func (f *Flock) try(locked *bool, flag uint32) (bool, error) { + f.m.Lock() + defer f.m.Unlock() + + if *locked { + return true, nil + } + + if f.fh == nil { + if err := f.setFh(); err != nil { + return false, err + } + } + + _, errNo := lockFileEx(syscall.Handle(f.fh.Fd()), flag|winLockfileFailImmediately, 0, 1, 0, &syscall.Overlapped{}) + + if errNo > 0 { + if errNo == ErrorLockViolation || errNo == syscall.ERROR_IO_PENDING { + return false, nil + } + + return false, errNo + } + + *locked = true + + return true, nil +} diff --git a/geg/os/gflock/gflock.go b/geg/os/gflock/gflock.go index 4a936a715..2fc22fc97 100644 --- a/geg/os/gflock/gflock.go +++ b/geg/os/gflock/gflock.go @@ -3,14 +3,14 @@ package main import ( "github.com/theckman/go-flock" "fmt" - "time" ) func main() { fileLock := flock.NewFlock("/var/lock/go-lock.lock") - fmt.Println(fileLock.Lock()) - fmt.Println(fileLock.Lock()) - time.Sleep(1000*time.Second) + + fmt.Println(fileLock.TryLock()) + fmt.Println(fileLock.TryRLock()) + //time.Sleep(1000*time.Second) //fmt.Println(locked) // fmt.Println(fileLock.Locked()) //fmt.Println(err)