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authorMáximo Cuadros <mcuadros@gmail.com>2017-07-25 14:08:44 +0200
committerMáximo Cuadros <mcuadros@gmail.com>2017-07-25 14:08:44 +0200
commit8e83055176bbbbbde206884f10dc238fd378b9b4 (patch)
treeea34e067f87bebdb26a8fe4832e2ce0421cde889 /utils/ioutil
parentef234e7e7355281499a63c4b22550df023b61fbf (diff)
downloadgo-git-8e83055176bbbbbde206884f10dc238fd378b9b4.tar.gz
ioutil: Context and OnError helpers
Diffstat (limited to 'utils/ioutil')
-rw-r--r--utils/ioutil/common.go96
-rw-r--r--utils/ioutil/common_test.go102
2 files changed, 197 insertions, 1 deletions
diff --git a/utils/ioutil/common.go b/utils/ioutil/common.go
index 73cc9c3..66044e2 100644
--- a/utils/ioutil/common.go
+++ b/utils/ioutil/common.go
@@ -3,8 +3,11 @@ package ioutil
import (
"bufio"
+ "context"
"errors"
"io"
+
+ "github.com/jbenet/go-context/io"
)
type readPeeker interface {
@@ -52,6 +55,21 @@ func NewReadCloser(r io.Reader, c io.Closer) io.ReadCloser {
return &readCloser{Reader: r, closer: c}
}
+type writeCloser struct {
+ io.Writer
+ closer io.Closer
+}
+
+func (r *writeCloser) Close() error {
+ return r.closer.Close()
+}
+
+// NewWriteCloser creates an `io.WriteCloser` with the given `io.Writer` and
+// `io.Closer`.
+func NewWriteCloser(w io.Writer, c io.Closer) io.WriteCloser {
+ return &writeCloser{Writer: w, closer: c}
+}
+
type writeNopCloser struct {
io.Writer
}
@@ -72,3 +90,81 @@ func CheckClose(c io.Closer, err *error) {
*err = cerr
}
}
+
+// NewContextWriter wraps a writer to make it respect given Context.
+// If there is a blocking write, the returned Writer will return whenever the
+// context is cancelled (the return values are n=0 and err=ctx.Err()).
+func NewContextWriter(ctx context.Context, w io.Writer) io.Writer {
+ return ctxio.NewWriter(ctx, w)
+}
+
+// NewContextReader wraps a reader to make it respect given Context.
+// If there is a blocking read, the returned Reader will return whenever the
+// context is cancelled (the return values are n=0 and err=ctx.Err()).
+func NewContextReader(ctx context.Context, r io.Reader) io.Reader {
+ return ctxio.NewReader(ctx, r)
+}
+
+// NewContextWriteCloser as NewContextWriter but with io.Closer interface.
+func NewContextWriteCloser(ctx context.Context, w io.WriteCloser) io.WriteCloser {
+ ctxw := ctxio.NewWriter(ctx, w)
+ return NewWriteCloser(ctxw, w)
+}
+
+// NewContextReadCloser as NewContextReader but with io.Closer interface.
+func NewContextReadCloser(ctx context.Context, r io.ReadCloser) io.ReadCloser {
+ ctxr := ctxio.NewReader(ctx, r)
+ return NewReadCloser(ctxr, r)
+}
+
+type readerOnError struct {
+ io.Reader
+ notify func(error)
+}
+
+// NewReaderOnError returns a io.Reader that call the notify function when an
+// unexpected (!io.EOF) error happends, after call Read function.
+func NewReaderOnError(r io.Reader, notify func(error)) io.Reader {
+ return &readerOnError{r, notify}
+}
+
+// NewReadCloserOnError returns a io.ReadCloser that call the notify function
+// when an unexpected (!io.EOF) error happends, after call Read function.
+func NewReadCloserOnError(r io.ReadCloser, notify func(error)) io.ReadCloser {
+ return NewReadCloser(NewReaderOnError(r, notify), r)
+}
+
+func (r *readerOnError) Read(buf []byte) (n int, err error) {
+ n, err = r.Reader.Read(buf)
+ if err != nil && err != io.EOF {
+ r.notify(err)
+ }
+
+ return
+}
+
+type writerOnError struct {
+ io.Writer
+ notify func(error)
+}
+
+// NewWriterOnError returns a io.Writer that call the notify function when an
+// unexpected (!io.EOF) error happends, after call Write function.
+func NewWriterOnError(w io.Writer, notify func(error)) io.Writer {
+ return &writerOnError{w, notify}
+}
+
+// NewWriteCloserOnError returns a io.WriteCloser that call the notify function
+//when an unexpected (!io.EOF) error happends, after call Write function.
+func NewWriteCloserOnError(w io.WriteCloser, notify func(error)) io.WriteCloser {
+ return NewWriteCloser(NewWriterOnError(w, notify), w)
+}
+
+func (r *writerOnError) Write(p []byte) (n int, err error) {
+ n, err = r.Writer.Write(p)
+ if err != nil && err != io.EOF {
+ r.notify(err)
+ }
+
+ return
+}
diff --git a/utils/ioutil/common_test.go b/utils/ioutil/common_test.go
index 2d6ef80..27bfa62 100644
--- a/utils/ioutil/common_test.go
+++ b/utils/ioutil/common_test.go
@@ -2,6 +2,7 @@ package ioutil
import (
"bytes"
+ "context"
"io/ioutil"
"strings"
"testing"
@@ -55,6 +56,106 @@ func (s *CommonSuite) TestNewReadCloser(c *C) {
c.Assert(closer.called, Equals, 1)
}
+func (s *CommonSuite) TestNewContextReader(c *C) {
+ buf := bytes.NewBuffer([]byte("12"))
+ ctx, close := context.WithCancel(context.Background())
+
+ r := NewContextReader(ctx, buf)
+
+ b := make([]byte, 1)
+ n, err := r.Read(b)
+ c.Assert(n, Equals, 1)
+ c.Assert(err, IsNil)
+
+ close()
+ n, err = r.Read(b)
+ c.Assert(n, Equals, 0)
+ c.Assert(err, NotNil)
+}
+
+func (s *CommonSuite) TestNewContextReadCloser(c *C) {
+ buf := NewReadCloser(bytes.NewBuffer([]byte("12")), &closer{})
+ ctx, close := context.WithCancel(context.Background())
+
+ r := NewContextReadCloser(ctx, buf)
+
+ b := make([]byte, 1)
+ n, err := r.Read(b)
+ c.Assert(n, Equals, 1)
+ c.Assert(err, IsNil)
+
+ close()
+ n, err = r.Read(b)
+ c.Assert(n, Equals, 0)
+ c.Assert(err, NotNil)
+
+ c.Assert(r.Close(), IsNil)
+}
+
+func (s *CommonSuite) TestNewContextWriter(c *C) {
+ buf := bytes.NewBuffer(nil)
+ ctx, close := context.WithCancel(context.Background())
+
+ r := NewContextWriter(ctx, buf)
+
+ n, err := r.Write([]byte("1"))
+ c.Assert(n, Equals, 1)
+ c.Assert(err, IsNil)
+
+ close()
+ n, err = r.Write([]byte("1"))
+ c.Assert(n, Equals, 0)
+ c.Assert(err, NotNil)
+}
+
+func (s *CommonSuite) TestNewContextWriteCloser(c *C) {
+ buf := NewWriteCloser(bytes.NewBuffer(nil), &closer{})
+ ctx, close := context.WithCancel(context.Background())
+
+ w := NewContextWriteCloser(ctx, buf)
+
+ n, err := w.Write([]byte("1"))
+ c.Assert(n, Equals, 1)
+ c.Assert(err, IsNil)
+
+ close()
+ n, err = w.Write([]byte("1"))
+ c.Assert(n, Equals, 0)
+ c.Assert(err, NotNil)
+
+ c.Assert(w.Close(), IsNil)
+}
+
+func (s *CommonSuite) TestNewWriteCloserOnError(c *C) {
+ buf := NewWriteCloser(bytes.NewBuffer(nil), &closer{})
+
+ ctx, close := context.WithCancel(context.Background())
+
+ var called error
+ w := NewWriteCloserOnError(NewContextWriteCloser(ctx, buf), func(err error) {
+ called = err
+ })
+
+ close()
+ w.Write(nil)
+
+ c.Assert(called, NotNil)
+}
+
+func (s *CommonSuite) TestNewReadCloserOnError(c *C) {
+ buf := NewReadCloser(bytes.NewBuffer(nil), &closer{})
+ ctx, close := context.WithCancel(context.Background())
+
+ var called error
+ w := NewReadCloserOnError(NewContextReadCloser(ctx, buf), func(err error) {
+ called = err
+ })
+
+ close()
+ w.Read(nil)
+
+ c.Assert(called, NotNil)
+}
func ExampleCheckClose() {
// CheckClose is commonly used with named return values
f := func() (err error) {
@@ -68,7 +169,6 @@ func ExampleCheckClose() {
// if err is not nil, CheckClose will assign any close errors to it
return err
-
}
err := f()