io: rename Copyn to CopyN.

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/5157045

src/cmd/gofix/Makefile

@@ -13,6 +13,7 @@ GOFILES=\
 	httpheaders.go\
 	httpserver.go\
 	imagenew.go\
+	iocopyn.go\
 	main.go\
 	math.go\
 	netdial.go\

src/cmd/gofix/iocopyn.go

+// 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"
+)
+
+var ioCopyNFix = fix{
+	"iocopyn",
+	ioCopyN,
+	`Rename io.Copyn to io.CopyN.
+
+http://codereview.appspot.com/5157045
+`,
+}
+
+func init() {
+	register(ioCopyNFix)
+}
+
+func ioCopyN(f *ast.File) bool {
+	if !imports(f, "io") {
+		return false
+	}
+
+	fixed := false
+	walk(f, func(n interface{}) {
+		if expr, ok := n.(ast.Expr); ok {
+			if isPkgDot(expr, "io", "Copyn") {
+				expr.(*ast.SelectorExpr).Sel.Name = "CopyN"
+				fixed = true
+				return
+			}
+		}
+	})
+	return fixed
+}

src/cmd/gofix/iocopyn_test.go

+// 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(ioCopyNTests)
+}
+
+var ioCopyNTests = []testCase{
+	{
+		Name: "io.CopyN.0",
+		In: `package main
+
+import (
+	"io"
+)
+
+func f() {
+	io.Copyn(dst, src)
+	foo.Copyn(dst, src)
+}
+`,
+		Out: `package main
+
+import (
+	"io"
+)
+
+func f() {
+	io.CopyN(dst, src)
+	foo.Copyn(dst, src)
+}
+`,
+	},
+}

src/pkg/archive/tar/reader.go

@@ -94,7 +94,7 @@ func (tr *Reader) skipUnread() {
 			return
 		}
 	}
-	_, tr.err = io.Copyn(ioutil.Discard, tr.r, nr)
+	_, tr.err = io.CopyN(ioutil.Discard, tr.r, nr)
 }
 
 func (tr *Reader) verifyChecksum(header []byte) bool {

src/pkg/http/fs.go

@@ -219,7 +219,7 @@ func serveFile(w ResponseWriter, r *Request, fs FileSystem, name string, redirec
 	w.WriteHeader(code)
 
 	if r.Method != "HEAD" {
-		io.Copyn(w, f, size)
+		io.CopyN(w, f, size)
 	}
 }
 

src/pkg/http/transport_test.go

@@ -474,7 +474,7 @@ func TestTransportGzip(t *testing.T) {
 		gz, _ := gzip.NewWriter(w)
 		gz.Write([]byte(testString))
 		if req.FormValue("body") == "large" {
-			io.Copyn(gz, rand.Reader, nRandBytes)
+			io.CopyN(gz, rand.Reader, nRandBytes)
 		}
 		gz.Close()
 	}))

src/pkg/io/io.go

@@ -256,15 +256,15 @@ func ReadFull(r Reader, buf []byte) (n int, err os.Error) {
 	return ReadAtLeast(r, buf, len(buf))
 }
 
-// Copyn copies n bytes (or until an error) from src to dst.
+// CopyN copies n bytes (or until an error) from src to dst.
 // It returns the number of bytes copied and the earliest
 // error encountered while copying.  Because Read can
 // return the full amount requested as well as an error
-// (including os.EOF), so can Copyn.
+// (including os.EOF), so can CopyN.
 //
 // If dst implements the ReaderFrom interface,
 // the copy is implemented by calling dst.ReadFrom(src).
-func Copyn(dst Writer, src Reader, n int64) (written int64, err os.Error) {
+func CopyN(dst Writer, src Reader, n int64) (written int64, err os.Error) {
 	// If the writer has a ReadFrom method, use it to do the copy.
 	// Avoids a buffer allocation and a copy.
 	if rt, ok := dst.(ReaderFrom); ok {

src/pkg/io/io_test.go

@@ -19,7 +19,7 @@ type Buffer struct {
 	WriterTo   // conflicts with and hides bytes.Buffer's WriterTo.
 }
 
-// Simple tests, primarily to verify the ReadFrom and WriteTo callouts inside Copy and Copyn.
+// Simple tests, primarily to verify the ReadFrom and WriteTo callouts inside Copy and CopyN.
 
 func TestCopy(t *testing.T) {
 	rb := new(Buffer)
@@ -51,33 +51,33 @@ func TestCopyWriteTo(t *testing.T) {
 	}
 }
 
-func TestCopyn(t *testing.T) {
+func TestCopyN(t *testing.T) {
 	rb := new(Buffer)
 	wb := new(Buffer)
 	rb.WriteString("hello, world.")
-	Copyn(wb, rb, 5)
+	CopyN(wb, rb, 5)
 	if wb.String() != "hello" {
-		t.Errorf("Copyn did not work properly")
+		t.Errorf("CopyN did not work properly")
 	}
 }
 
-func TestCopynReadFrom(t *testing.T) {
+func TestCopyNReadFrom(t *testing.T) {
 	rb := new(Buffer)
 	wb := new(bytes.Buffer) // implements ReadFrom.
 	rb.WriteString("hello")
-	Copyn(wb, rb, 5)
+	CopyN(wb, rb, 5)
 	if wb.String() != "hello" {
-		t.Errorf("Copyn did not work properly")
+		t.Errorf("CopyN did not work properly")
 	}
 }
 
-func TestCopynWriteTo(t *testing.T) {
+func TestCopyNWriteTo(t *testing.T) {
 	rb := new(bytes.Buffer) // implements WriteTo.
 	wb := new(Buffer)
 	rb.WriteString("hello, world.")
-	Copyn(wb, rb, 5)
+	CopyN(wb, rb, 5)
 	if wb.String() != "hello" {
-		t.Errorf("Copyn did not work properly")
+		t.Errorf("CopyN did not work properly")
 	}
 }
 
@@ -89,30 +89,30 @@ func (w *noReadFrom) Write(p []byte) (n int, err os.Error) {
 	return w.w.Write(p)
 }
 
-func TestCopynEOF(t *testing.T) {
+func TestCopyNEOF(t *testing.T) {
 	// Test that EOF behavior is the same regardless of whether
-	// argument to Copyn has ReadFrom.
+	// argument to CopyN has ReadFrom.
 
 	b := new(bytes.Buffer)
 
-	n, err := Copyn(&noReadFrom{b}, strings.NewReader("foo"), 3)
+	n, err := CopyN(&noReadFrom{b}, strings.NewReader("foo"), 3)
 	if n != 3 || err != nil {
-		t.Errorf("Copyn(noReadFrom, foo, 3) = %d, %v; want 3, nil", n, err)
+		t.Errorf("CopyN(noReadFrom, foo, 3) = %d, %v; want 3, nil", n, err)
 	}
 
-	n, err = Copyn(&noReadFrom{b}, strings.NewReader("foo"), 4)
+	n, err = CopyN(&noReadFrom{b}, strings.NewReader("foo"), 4)
 	if n != 3 || err != os.EOF {
-		t.Errorf("Copyn(noReadFrom, foo, 4) = %d, %v; want 3, EOF", n, err)
+		t.Errorf("CopyN(noReadFrom, foo, 4) = %d, %v; want 3, EOF", n, err)
 	}
 
-	n, err = Copyn(b, strings.NewReader("foo"), 3) // b has read from
+	n, err = CopyN(b, strings.NewReader("foo"), 3) // b has read from
 	if n != 3 || err != nil {
-		t.Errorf("Copyn(bytes.Buffer, foo, 3) = %d, %v; want 3, nil", n, err)
+		t.Errorf("CopyN(bytes.Buffer, foo, 3) = %d, %v; want 3, nil", n, err)
 	}
 
-	n, err = Copyn(b, strings.NewReader("foo"), 4) // b has read from
+	n, err = CopyN(b, strings.NewReader("foo"), 4) // b has read from
 	if n != 3 || err != os.EOF {
-		t.Errorf("Copyn(bytes.Buffer, foo, 4) = %d, %v; want 3, EOF", n, err)
+		t.Errorf("CopyN(bytes.Buffer, foo, 4) = %d, %v; want 3, EOF", n, err)
 	}
 }
 

src/pkg/mime/multipart/formdata.go

@@ -47,7 +47,7 @@ func (r *Reader) ReadForm(maxMemory int64) (f *Form, err os.Error) {
 
 		if filename == "" {
 			// value, store as string in memory
-			n, err := io.Copyn(&b, p, maxValueBytes)
+			n, err := io.CopyN(&b, p, maxValueBytes)
 			if err != nil && err != os.EOF {
 				return nil, err
 			}
@@ -64,7 +64,7 @@ func (r *Reader) ReadForm(maxMemory int64) (f *Form, err os.Error) {
 			Filename: filename,
 			Header:   p.Header,
 		}
-		n, err := io.Copyn(&b, p, maxMemory+1)
+		n, err := io.CopyN(&b, p, maxMemory+1)
 		if err != nil && err != os.EOF {
 			return nil, err
 		}

src/pkg/mime/multipart/multipart.go

@@ -146,7 +146,7 @@ func (bp *Part) Read(p []byte) (n int, err os.Error) {
 		return 0, io.ErrUnexpectedEOF
 	}
 	if nCopy > 0 {
-		if _, err := io.Copyn(bp.buffer, bp.mr.bufReader, int64(nCopy)); err != nil {
+		if _, err := io.CopyN(bp.buffer, bp.mr.bufReader, int64(nCopy)); err != nil {
 			return 0, err
 		}
 	}