mirror of https://github.com/siddontang/go.git
78 lines
2.0 KiB
Go
78 lines
2.0 KiB
Go
// Copyright 2014 The LevelDB-Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package filelock
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import (
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"bytes"
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"flag"
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"io/ioutil"
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"os"
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"os/exec"
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"testing"
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)
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var lockFilename = flag.String("lockfile", "", "File to lock. Non-empty value pimples child process.")
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func spawn(prog, filename string) ([]byte, error) {
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return exec.Command(prog, "-lockfile", filename, "-test.v",
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"-test.run=TestLock$").CombinedOutput()
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}
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// TestLock locks a file, spawns a second process that attempts to grab the
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// lock to verify it fails.
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// Then it closes the lock, and spawns a third copy to verify it can be
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// relocked.
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func TestLock(t *testing.T) {
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child := *lockFilename != ""
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var filename string
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if child {
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filename = *lockFilename
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} else {
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f, err := ioutil.TempFile("", "")
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if err != nil {
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t.Fatal(err)
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}
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filename = f.Name()
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defer os.Remove(filename)
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}
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// Avoid truncating an existing, non-empty file.
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fi, err := os.Stat(filename)
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if err == nil && fi.Size() != 0 {
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t.Fatalf("The file %s is not empty", filename)
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}
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t.Logf("Locking %s\n", filename)
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lock, err := Lock(filename)
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if err != nil {
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t.Fatalf("Could not lock %s: %v", filename, err)
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}
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if !child {
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t.Logf("Spawning child, should fail to grab lock.")
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out, err := spawn(os.Args[0], filename)
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if err == nil {
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t.Fatalf("Attempt to grab open lock should have failed.\n%s", out)
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}
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if !bytes.Contains(out, []byte("Could not lock")) {
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t.Fatalf("Child failed with unexpected output: %s\n", out)
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}
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t.Logf("Child failed to grab lock as expected.")
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}
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t.Logf("Unlocking %s", filename)
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if err := lock.Close(); err != nil {
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t.Fatalf("Could not unlock %s: %v", filename, err)
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}
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if !child {
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t.Logf("Spawning child, should successfully grab lock.")
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if out, err := spawn(os.Args[0], filename); err != nil {
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t.Fatalf("Attempt to re-open lock should have succeeded: %v\n%s",
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err, out)
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}
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t.Logf("Child grabbed lock.")
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}
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}
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