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Publish types PipeReader and PipeWriter

Browse Source 
to expose new CloseWithError methods.

R=r
DELTA=161  (72 added, 15 deleted, 74 changed)
OCL=29980
CL=30003
This commit is contained in:
Russ Cox 2009-06-06 21:51:05 -07:00
parent 3c06bd6201
commit 6defc25c83
2 changed files with 140 additions and 83 deletions
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87
src/lib/io/pipe.go
View File

@ -21,7 +21,9 @@ type pipeReturn struct {
// Shared pipe structure.
type pipe struct {
rclosed bool; // Read end closed?
rerr os.Error; // Error supplied to CloseReader
wclosed bool; // Write end closed?
werr os.Error; // Error supplied to CloseWriter
wpend []byte; // Written data waiting to be read.
wtot int; // Bytes consumed so far in current write.
cr chan []byte; // Write sends data here...
@ -39,7 +41,7 @@ func (p *pipe) Read(data []byte) (n int, err os.Error) {
p.wpend = <-p.cr;
}
if p.wpend == nil {
return 0, nil;
return 0, p.werr;
}
p.wtot = 0;
}
@ -70,7 +72,7 @@ func (p *pipe) Write(data []byte) (n int, err os.Error) {
return 0, os.EINVAL;
}
if p.rclosed {
return 0, os.EPIPE;
return 0, p.rerr;
}
// Send data to reader.
@ -81,29 +83,34 @@ func (p *pipe) Write(data []byte) (n int, err os.Error) {
return res.n, res.err;
}
func (p *pipe) CloseReader() os.Error {
func (p *pipe) CloseReader(rerr os.Error) os.Error {
if p == nil || p.rclosed {
return os.EINVAL;
}
// Stop any future writes.
p.rclosed = true;
if rerr == nil {
rerr = os.EPIPE;
}
p.rerr = rerr;
// Stop the current write.
if !p.wclosed {
p.cw <- pipeReturn{p.wtot, os.EPIPE};
p.cw <- pipeReturn{p.wtot, rerr};
}
return nil;
}
func (p *pipe) CloseWriter() os.Error {
func (p *pipe) CloseWriter(werr os.Error) os.Error {
if p == nil || p.wclosed {
return os.EINVAL;
}
// Stop any future reads.
p.wclosed = true;
p.werr = werr;
// Stop the current read.
if !p.rclosed {
@ -121,70 +128,98 @@ func (p *pipe) CloseWriter() os.Error {
// 2. Clients cannot use interface conversions on the
// read end to find the Write method, and vice versa.
// Read half of pipe.
type pipeRead struct {
// A PipeReader is the read half of a pipe.
type PipeReader struct {
lock sync.Mutex;
p *pipe;
}
func (r *pipeRead) Read(data []byte) (n int, err os.Error) {
// Read implements the standard Read interface:
// it reads data from the pipe, blocking until a writer
// arrives or the write end is closed.
// If the write end is closed with an error, that error is
// returned as err; otherwise err is nil.
func (r *PipeReader) Read(data []byte) (n int, err os.Error) {
r.lock.Lock();
defer r.lock.Unlock();
return r.p.Read(data);
}
func (r *pipeRead) Close() os.Error {
// Close closes the reader; subsequent writes to the
// write half of the pipe will return the error os.EPIPE.
func (r *PipeReader) Close() os.Error {
r.lock.Lock();
defer r.lock.Unlock();
return r.p.CloseReader();
return r.p.CloseReader(nil);
}
func (r *pipeRead) finish() {
// CloseWithError closes the reader; subsequent writes
// to the write half of the pipe will return the error rerr.
func (r *PipeReader) CloseWithError(rerr os.Error) os.Error {
r.lock.Lock();
defer r.lock.Unlock();
return r.p.CloseReader(rerr);
}
func (r *PipeReader) finish() {
r.Close();
}
// Write half of pipe.
type pipeWrite struct {
type PipeWriter struct {
lock sync.Mutex;
p *pipe;
}
func (w *pipeWrite) Write(data []byte) (n int, err os.Error) {
// Write implements the standard Write interface:
// it writes data to the pipe, blocking until readers
// have consumed all the data or the read end is closed.
// If the read end is closed with an error, that err is
// returned as err; otherwise err is os.EPIPE.
func (w *PipeWriter) Write(data []byte) (n int, err os.Error) {
w.lock.Lock();
defer w.lock.Unlock();
return w.p.Write(data);
}
func (w *pipeWrite) Close() os.Error {
// Close closes the writer; subsequent reads from the
// read half of the pipe will return no bytes and a nil error.
func (w *PipeWriter) Close() os.Error {
w.lock.Lock();
defer w.lock.Unlock();
return w.p.CloseWriter();
return w.p.CloseWriter(nil);
}
func (w *pipeWrite) finish() {
// CloseWithError closes the writer; subsequent reads from the
// read half of the pipe will return no bytes and the error werr.
func (w *PipeWriter) CloseWithError(werr os.Error) os.Error {
w.lock.Lock();
defer w.lock.Unlock();
return w.p.CloseWriter(werr);
}
func (w *PipeWriter) finish() {
w.Close();
}
// Pipe creates a synchronous in-memory pipe.
// Used to connect code expecting an io.Reader
// It can be used to connect code expecting an io.Reader
// with code expecting an io.Writer.
//
// Reads on one end are matched by writes on the other.
// Writes don't complete until all the data has been
// written or the read end is closed. Reads return
// any available data or block until the next write
// or the write end is closed.
func Pipe() (io.ReadCloser, io.WriteCloser) {
// Reads on one end are matched with writes on the other,
// copying data directly between the two; there is no internal buffering.
func Pipe() (*PipeReader, *PipeWriter) {
p := new(pipe);
p.cr = make(chan []byte, 1);
p.cw = make(chan pipeReturn, 1);
r := new(pipeRead);
r := new(PipeReader);
r.p = p;
w := new(pipeWrite);
w := new(PipeWriter);
w.p = p;
return r, w;
}

136
src/lib/io/pipe_test.go
View File

@ -5,6 +5,7 @@
package io
import (
"fmt";
"io";
"os";
"testing";
@ -132,72 +133,93 @@ func TestPipe3(t *testing.T) {
// Test read after/before writer close.
func delayClose(t *testing.T, cl Closer, ch chan int) {
time.Sleep(1000*1000); // 1 ms
if err := cl.Close(); err != nil {
type closer interface {
CloseWithError(os.Error) os.Error;
Close() os.Error;
}
type pipeTest struct {
async bool;
err os.Error;
closeWithError bool;
}
func (p pipeTest) String() string {
return fmt.Sprintf("async=%v err=%v closeWithError=%v", p.async, p.err, p.closeWithError);
}
var pipeTests = []pipeTest {
pipeTest{ true, nil, false },
pipeTest{ true, nil, true },
pipeTest{ true, io.ErrShortWrite, true },
pipeTest{ false, nil, false },
pipeTest{ false, nil, true },
pipeTest{ false, io.ErrShortWrite, true },
}
func delayClose(t *testing.T, cl closer, ch chan int, tt pipeTest) {
time.Sleep(1e6); // 1 ms
var err os.Error;
if tt.closeWithError {
err = cl.CloseWithError(tt.err);
} else {
err = cl.Close();
}
if err != nil {
t.Errorf("delayClose: %v", err);
}
ch <- 0;
}
func testPipeReadClose(t *testing.T, async bool) {
c := make(chan int, 1);
r, w := Pipe();
if async {
go delayClose(t, w, c);
} else {
delayClose(t, w, c);
}
var buf = make([]byte, 64);
n, err := r.Read(buf);
<-c;
if err != nil {
t.Errorf("read from closed pipe: %v", err);
}
if n != 0 {
t.Errorf("read on closed pipe returned %d", n);
}
if err = r.Close(); err != nil {
t.Errorf("r.Close: %v", err);
func TestPipeReadClose(t *testing.T) {
for _, tt := range pipeTests {
c := make(chan int, 1);
r, w := Pipe();
if tt.async {
go delayClose(t, w, c, tt);
} else {
delayClose(t, w, c, tt);
}
var buf = make([]byte, 64);
n, err := r.Read(buf);
<-c;
if err != tt.err {
t.Errorf("read from closed pipe: %v want %v", err, tt.err);
}
if n != 0 {
t.Errorf("read on closed pipe returned %d", n);
}
if err = r.Close(); err != nil {
t.Errorf("r.Close: %v", err);
}
}
}
// Test write after/before reader close.
func testPipeWriteClose(t *testing.T, async bool) {
c := make(chan int, 1);
r, w := Pipe();
if async {
go delayClose(t, r, c);
} else {
delayClose(t, r, c);
}
n, err := WriteString(w, "hello, world");
<-c;
if err != os.EPIPE {
t.Errorf("write on closed pipe: %v", err);
}
if n != 0 {
t.Errorf("write on closed pipe returned %d", n);
}
if err = w.Close(); err != nil {
t.Errorf("w.Close: %v", err);
func TestPipeWriteClose(t *testing.T) {
for _, tt := range pipeTests {
c := make(chan int, 1);
r, w := Pipe();
if tt.async {
go delayClose(t, r, c, tt);
} else {
delayClose(t, r, c, tt);
}
n, err := WriteString(w, "hello, world");
<-c;
expect := tt.err;
if expect == nil {
expect = os.EPIPE;
}
if err != expect {
t.Errorf("write on closed pipe: %v want %v", err, expect);
}
if n != 0 {
t.Errorf("write on closed pipe returned %d", n);
}
if err = w.Close(); err != nil {
t.Errorf("w.Close: %v", err);
}
}
}
func TestPipeReadCloseAsync(t *testing.T) {
testPipeReadClose(t, true);
}
func TestPipeReadCloseSync(t *testing.T) {
testPipeReadClose(t, false);
}
func TestPipeWriteCloseAsync(t *testing.T) {
testPipeWriteClose(t, true);
}
func TestPipeWriteCloseSync(t *testing.T) {
testPipeWriteClose(t, false);
}