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os: drop the Wait function and the options to Process.Wait

They are portability problems and the options are almost always zero in practice anyway.

R=golang-dev, dsymonds, r, bradfitz
CC=golang-dev
https://golang.org/cl/5688046
This commit is contained in:
Rob Pike 2012-02-20 15:36:08 +11:00
parent a9e57f743d
commit b5a3bd5ff6
12 changed files with 137 additions and 67 deletions

View File

@ -8,7 +8,7 @@
<!-- Center the tables, and disable the 1995-era 3D borders --> <!-- Center the tables, and disable the 1995-era 3D borders -->
<style> <style type="text/css">
table { margin-left: auto; margin-right: auto; border-style: none; } table { margin-left: auto; margin-right: auto; border-style: none; }
hr { border-style: none; border-top: 1px solid black; } hr { border-style: none; border-top: 1px solid black; }
</style> </style>
@ -1460,9 +1460,20 @@ use <a href="/pkg/os/#Environ"><code>os.Environ</code></a> or
<a href="/pkg/syscall/#Getenv"><code>syscall.Getenv</code></a>. <a href="/pkg/syscall/#Getenv"><code>syscall.Getenv</code></a>.
</p> </p>
<p>
The <a href="/pkg/os/#Process.Wait"><code>Process.Wait</code></a> method has
dropped its option argument and the associated constants are gone
from the package.
Also, the function <code>Wait</code> is gone; only the method of
the <code>Process</code> type persists.
</p>
<p> <p>
<em>Updating</em>: <em>Updating</em>:
Affected code will be caught by the compiler and must be updated by hand. Gofix will rewrite calls to <code>os.Wait</code> with an explicit zero
argument, dropping the argument.
All other changes will be caught by the compiler and must be updated by hand.
</p> </p>
<h4 id="os_fileinfo">The os.FileInfo type</h4> <h4 id="os_fileinfo">The os.FileInfo type</h4>
@ -1915,7 +1926,7 @@ so that exported function definitions can use types defined there.
This has the effect of compiling the preamble multiple times, so a This has the effect of compiling the preamble multiple times, so a
package using <code>//export</code> must not put function definitions package using <code>//export</code> must not put function definitions
or variable initializations in the C preamble. or variable initializations in the C preamble.
</p </p>
<h2 id="releases">Packaged releases</h2> <h2 id="releases">Packaged releases</h2>

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@ -4,7 +4,7 @@
{{donotedit}} {{donotedit}}
<!-- Center the tables, and disable the 1995-era 3D borders --> <!-- Center the tables, and disable the 1995-era 3D borders -->
<style> <style type="text/css">
table { margin-left: auto; margin-right: auto; border-style: none; } table { margin-left: auto; margin-right: auto; border-style: none; }
hr { border-style: none; border-top: 1px solid black; } hr { border-style: none; border-top: 1px solid black; }
</style> </style>
@ -1363,9 +1363,20 @@ use <a href="/pkg/os/#Environ"><code>os.Environ</code></a> or
<a href="/pkg/syscall/#Getenv"><code>syscall.Getenv</code></a>. <a href="/pkg/syscall/#Getenv"><code>syscall.Getenv</code></a>.
</p> </p>
<p>
The <a href="/pkg/os/#Process.Wait"><code>Process.Wait</code></a> method has
dropped its option argument and the associated constants are gone
from the package.
Also, the function <code>Wait</code> is gone; only the method of
the <code>Process</code> type persists.
</p>
<p> <p>
<em>Updating</em>: <em>Updating</em>:
Affected code will be caught by the compiler and must be updated by hand. Gofix will rewrite calls to <code>os.Wait</code> with an explicit zero
argument, dropping the argument.
All other changes will be caught by the compiler and must be updated by hand.
</p> </p>
<h4 id="os_fileinfo">The os.FileInfo type</h4> <h4 id="os_fileinfo">The os.FileInfo type</h4>
@ -1787,7 +1798,7 @@ so that exported function definitions can use types defined there.
This has the effect of compiling the preamble multiple times, so a This has the effect of compiling the preamble multiple times, so a
package using <code>//export</code> must not put function definitions package using <code>//export</code> must not put function definitions
or variable initializations in the C preamble. or variable initializations in the C preamble.
</p </p>
<h2 id="releases">Packaged releases</h2> <h2 id="releases">Packaged releases</h2>

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@ -56,7 +56,7 @@ func run(stdin []byte, argv []string) (stdout, stderr []byte, ok bool) {
<-c <-c
<-c <-c
w, err := p.Wait(0) w, err := p.Wait()
if err != nil { if err != nil {
fatalf("%s", err) fatalf("%s", err)
} }

56
src/cmd/fix/oswait.go Normal file
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@ -0,0 +1,56 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
import (
"go/ast"
)
func init() {
register(oswaitFix)
}
var oswaitFix = fix{
"oswait",
"2012-02-20",
oswait,
`Delete options from os.Wait. If the option is the literal 0, rewrite the call.
http://codereview.appspot.com/5688046
`,
}
func oswait(f *ast.File) bool {
if !imports(f, "os") {
return false
}
fixed := false
walk(f, func(n interface{}) {
call, ok := n.(*ast.CallExpr)
if !ok {
return
}
if !isPkgDot(call.Fun, "os", "Wait") {
return
}
args := call.Args
const warning = "call to Process.Wait must be fixed manually"
if len(args) != 1 {
// Shouldn't happen, but check.
warn(call.Pos(), warning)
return
}
if basicLit, ok := args[0].(*ast.BasicLit); !ok || basicLit.Value != "0" {
warn(call.Pos(), warning)
return
}
call.Args = nil
fixed = true
})
return fixed
}

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@ -0,0 +1,41 @@
// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package main
func init() {
addTestCases(oswaitTests, oswait)
}
var oswaitTests = []testCase{
{
Name: "oswait.0",
In: `package main
import (
"os"
)
func f() {
os.Wait()
os.Wait(0)
os.Wait(1)
os.Wait(A | B)
}
`,
Out: `package main
import (
"os"
)
func f() {
os.Wait()
os.Wait()
os.Wait(1)
os.Wait(A | B)
}
`,
},
}

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@ -103,7 +103,7 @@ func exec(rw http.ResponseWriter, args []string) (status int) {
var buf bytes.Buffer var buf bytes.Buffer
io.Copy(&buf, r) io.Copy(&buf, r)
wait, err := p.Wait(0) wait, err := p.Wait()
if err != nil { if err != nil {
os.Stderr.Write(buf.Bytes()) os.Stderr.Write(buf.Bytes())
log.Printf("os.Wait(%d, 0): %v", p.Pid, err) log.Printf("os.Wait(%d, 0): %v", p.Pid, err)

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@ -291,7 +291,7 @@ func (c *Cmd) Wait() error {
return errors.New("exec: Wait was already called") return errors.New("exec: Wait was already called")
} }
c.finished = true c.finished = true
msg, err := c.Process.Wait(0) msg, err := c.Process.Wait()
c.Waitmsg = msg c.Waitmsg = msg
var copyError error var copyError error

View File

@ -70,9 +70,8 @@ type Waitmsg struct {
} }
// Wait waits for the Process to exit or stop, and then returns a // Wait waits for the Process to exit or stop, and then returns a
// Waitmsg describing its status and an error, if any. The options // Waitmsg describing its status and an error, if any.
// (WNOHANG etc.) affect the behavior of the Wait call. func (p *Process) Wait() (w *Waitmsg, err error) {
func (p *Process) Wait(options int) (w *Waitmsg, err error) {
var waitmsg syscall.Waitmsg var waitmsg syscall.Waitmsg
if p.Pid == -1 { if p.Pid == -1 {
@ -95,20 +94,6 @@ func (p *Process) Wait(options int) (w *Waitmsg, err error) {
return &Waitmsg{waitmsg}, nil return &Waitmsg{waitmsg}, nil
} }
// Wait waits for process pid to exit or stop, and then returns a
// Waitmsg describing its status and an error, if any. The options
// (WNOHANG etc.) affect the behavior of the Wait call.
// Wait is equivalent to calling FindProcess and then Wait
// and Release on the result.
func Wait(pid int, options int) (w *Waitmsg, err error) {
p, e := FindProcess(pid)
if e != nil {
return nil, e
}
defer p.Release()
return p.Wait(options)
}
// Release releases any resources associated with the Process. // Release releases any resources associated with the Process.
func (p *Process) Release() error { func (p *Process) Release() error {
// NOOP for Plan 9. // NOOP for Plan 9.

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@ -56,20 +56,6 @@ type Waitmsg struct {
Rusage *syscall.Rusage // System-dependent resource usage info. Rusage *syscall.Rusage // System-dependent resource usage info.
} }
// Wait waits for process pid to exit or stop, and then returns a
// Waitmsg describing its status and an error, if any. The options
// (WNOHANG etc.) affect the behavior of the Wait call.
// Wait is equivalent to calling FindProcess and then Wait
// and Release on the result.
func Wait(pid int, options int) (w *Waitmsg, err error) {
p, e := FindProcess(pid)
if e != nil {
return nil, e
}
defer p.Release()
return p.Wait(options)
}
// Convert i to decimal string. // Convert i to decimal string.
func itod(i int) string { func itod(i int) string {
if i == 0 { if i == 0 {

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@ -12,43 +12,23 @@ import (
"syscall" "syscall"
) )
// Options for Wait.
const (
WNOHANG = syscall.WNOHANG // Don't wait if no process has exited.
WSTOPPED = syscall.WSTOPPED // If set, status of stopped subprocesses is also reported.
WUNTRACED = syscall.WUNTRACED // Usually an alias for WSTOPPED.
WRUSAGE = 1 << 20 // Record resource usage.
)
// WRUSAGE must not be too high a bit, to avoid clashing with Linux's
// WCLONE, WALL, and WNOTHREAD flags, which sit in the top few bits of
// the options
// Wait waits for the Process to exit or stop, and then returns a // Wait waits for the Process to exit or stop, and then returns a
// Waitmsg describing its status and an error, if any. The options // Waitmsg describing its status and an error, if any.
// (WNOHANG etc.) affect the behavior of the Wait call. func (p *Process) Wait() (w *Waitmsg, err error) {
func (p *Process) Wait(options int) (w *Waitmsg, err error) {
if p.Pid == -1 { if p.Pid == -1 {
return nil, syscall.EINVAL return nil, syscall.EINVAL
} }
var status syscall.WaitStatus var status syscall.WaitStatus
var rusage *syscall.Rusage pid1, e := syscall.Wait4(p.Pid, &status, 0, nil)
if options&WRUSAGE != 0 {
rusage = new(syscall.Rusage)
options ^= WRUSAGE
}
pid1, e := syscall.Wait4(p.Pid, &status, options, rusage)
if e != nil { if e != nil {
return nil, NewSyscallError("wait", e) return nil, NewSyscallError("wait", e)
} }
// With WNOHANG pid is 0 if child has not exited. if pid1 != 0 {
if pid1 != 0 && options&WSTOPPED == 0 {
p.done = true p.done = true
} }
w = new(Waitmsg) w = new(Waitmsg)
w.Pid = pid1 w.Pid = pid1
w.WaitStatus = status w.WaitStatus = status
w.Rusage = rusage
return w, nil return w, nil
} }

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@ -13,7 +13,7 @@ import (
// Wait waits for the Process to exit or stop, and then returns a // Wait waits for the Process to exit or stop, and then returns a
// Waitmsg describing its status and an error, if any. // Waitmsg describing its status and an error, if any.
func (p *Process) Wait(options int) (w *Waitmsg, err error) { func (p *Process) Wait() (w *Waitmsg, err error) {
s, e := syscall.WaitForSingleObject(syscall.Handle(p.handle), syscall.INFINITE) s, e := syscall.WaitForSingleObject(syscall.Handle(p.handle), syscall.INFINITE)
switch s { switch s {
case syscall.WAIT_OBJECT_0: case syscall.WAIT_OBJECT_0:

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@ -541,7 +541,7 @@ func exec(t *testing.T, dir, cmd string, args []string, expect string) {
t.Errorf("exec %q returned %q wanted %q", t.Errorf("exec %q returned %q wanted %q",
strings.Join(append([]string{cmd}, args...), " "), output, expect) strings.Join(append([]string{cmd}, args...), " "), output, expect)
} }
p.Wait(0) p.Wait()
} }
func TestStartProcess(t *testing.T) { func TestStartProcess(t *testing.T) {
@ -853,7 +853,7 @@ func run(t *testing.T, cmd []string) string {
var b bytes.Buffer var b bytes.Buffer
io.Copy(&b, r) io.Copy(&b, r)
_, err = p.Wait(0) _, err = p.Wait()
if err != nil { if err != nil {
t.Fatalf("run hostname Wait: %v", err) t.Fatalf("run hostname Wait: %v", err)
} }