libgo: update to Go1.14beta1

Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/214297

10 files changed, 150 insertions, 43 deletions

diff --git a/libgo/go/io/io.go b/libgo/go/io/io.go
index 2010770..9cc3086 100644
--- a/libgo/go/io/io.go
+++ b/libgo/go/io/io.go
@@ -368,6 +368,9 @@ func Copy(dst Writer, src Reader) (written int64, err error) {
 // provided buffer (if one is required) rather than allocating a
 // temporary one. If buf is nil, one is allocated; otherwise if it has
 // zero length, CopyBuffer panics.
+//
+// If either src implements WriterTo or dst implements ReaderFrom,
+// buf will not be used to perform the copy.
 func CopyBuffer(dst Writer, src Reader, buf []byte) (written int64, err error) {
 	if buf != nil && len(buf) == 0 {
 		panic("empty buffer in io.CopyBuffer")
diff --git a/libgo/go/io/io_test.go b/libgo/go/io/io_test.go
index 0e4ce61..ca90403 100644
--- a/libgo/go/io/io_test.go
+++ b/libgo/go/io/io_test.go
@@ -13,7 +13,7 @@ import (
 	"testing"
 )
 
-// An version of bytes.Buffer without ReadFrom and WriteTo
+// A version of bytes.Buffer without ReadFrom and WriteTo
 type Buffer struct {
 	bytes.Buffer
 	ReaderFrom // conflicts with and hides bytes.Buffer's ReaderFrom.
diff --git a/libgo/go/io/ioutil/example_test.go b/libgo/go/io/ioutil/example_test.go
index a7d340b..bc2b6fb 100644
--- a/libgo/go/io/ioutil/example_test.go
+++ b/libgo/go/io/ioutil/example_test.go
@@ -53,6 +53,29 @@ func ExampleTempDir() {
 	}
 }
 
+func ExampleTempDir_suffix() {
+	parentDir := os.TempDir()
+	logsDir, err := ioutil.TempDir(parentDir, "*-logs")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer os.RemoveAll(logsDir) // clean up
+
+	// Logs can be cleaned out earlier if needed by searching
+	// for all directories whose suffix ends in *-logs.
+	globPattern := filepath.Join(parentDir, "*-logs")
+	matches, err := filepath.Glob(globPattern)
+	if err != nil {
+		log.Fatalf("Failed to match %q: %v", globPattern, err)
+	}
+
+	for _, match := range matches {
+		if err := os.RemoveAll(match); err != nil {
+			log.Printf("Failed to remove %q: %v", match, err)
+		}
+	}
+}
+
 func ExampleTempFile() {
 	content := []byte("temporary file's content")
 	tmpfile, err := ioutil.TempFile("", "example")
diff --git a/libgo/go/io/ioutil/ioutil.go b/libgo/go/io/ioutil/ioutil.go
index 674b270..b1cb841 100644
--- a/libgo/go/io/ioutil/ioutil.go
+++ b/libgo/go/io/ioutil/ioutil.go
@@ -74,17 +74,14 @@ func ReadFile(filename string) ([]byte, error) {
 }
 
 // WriteFile writes data to a file named by filename.
-// If the file does not exist, WriteFile creates it with permissions perm;
-// otherwise WriteFile truncates it before writing.
+// If the file does not exist, WriteFile creates it with permissions perm
+// (before umask); otherwise WriteFile truncates it before writing.
 func WriteFile(filename string, data []byte, perm os.FileMode) error {
 	f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
 	if err != nil {
 		return err
 	}
-	n, err := f.Write(data)
-	if err == nil && n < len(data) {
-		err = io.ErrShortWrite
-	}
+	_, err = f.Write(data)
 	if err1 := f.Close(); err == nil {
 		err = err1
 	}
diff --git a/libgo/go/io/ioutil/ioutil_test.go b/libgo/go/io/ioutil/ioutil_test.go
index 81fc602..1fc4c8b 100644
--- a/libgo/go/io/ioutil/ioutil_test.go
+++ b/libgo/go/io/ioutil/ioutil_test.go
@@ -5,7 +5,9 @@
 package ioutil
 
 import (
+	"bytes"
 	"os"
+	"path/filepath"
 	"testing"
 )
 
@@ -63,6 +65,38 @@ func TestWriteFile(t *testing.T) {
 	os.Remove(filename) // ignore error
 }
 
+func TestReadOnlyWriteFile(t *testing.T) {
+	if os.Getuid() == 0 {
+		t.Skipf("Root can write to read-only files anyway, so skip the read-only test.")
+	}
+
+	// We don't want to use TempFile directly, since that opens a file for us as 0600.
+	tempDir, err := TempDir("", t.Name())
+	if err != nil {
+		t.Fatalf("TempDir %s: %v", t.Name(), err)
+	}
+	defer os.RemoveAll(tempDir)
+	filename := filepath.Join(tempDir, "blurp.txt")
+
+	shmorp := []byte("shmorp")
+	florp := []byte("florp")
+	err = WriteFile(filename, shmorp, 0444)
+	if err != nil {
+		t.Fatalf("WriteFile %s: %v", filename, err)
+	}
+	err = WriteFile(filename, florp, 0444)
+	if err == nil {
+		t.Fatalf("Expected an error when writing to read-only file %s", filename)
+	}
+	got, err := ReadFile(filename)
+	if err != nil {
+		t.Fatalf("ReadFile %s: %v", filename, err)
+	}
+	if !bytes.Equal(got, shmorp) {
+		t.Fatalf("want %s, got %s", shmorp, got)
+	}
+}
+
 func TestReadDir(t *testing.T) {
 	dirname := "rumpelstilzchen"
 	_, err := ReadDir(dirname)
diff --git a/libgo/go/io/ioutil/tempfile.go b/libgo/go/io/ioutil/tempfile.go
index ba8783b..3aa23c5 100644
--- a/libgo/go/io/ioutil/tempfile.go
+++ b/libgo/go/io/ioutil/tempfile.go
@@ -52,12 +52,7 @@ func TempFile(dir, pattern string) (f *os.File, err error) {
 		dir = os.TempDir()
 	}
 
-	var prefix, suffix string
-	if pos := strings.LastIndex(pattern, "*"); pos != -1 {
-		prefix, suffix = pattern[:pos], pattern[pos+1:]
-	} else {
-		prefix = pattern
-	}
+	prefix, suffix := prefixAndSuffix(pattern)
 
 	nconflict := 0
 	for i := 0; i < 10000; i++ {
@@ -76,21 +71,36 @@ func TempFile(dir, pattern string) (f *os.File, err error) {
 	return
 }
 
-// TempDir creates a new temporary directory in the directory dir
-// with a name beginning with prefix and returns the path of the
-// new directory. If dir is the empty string, TempDir uses the
+// prefixAndSuffix splits pattern by the last wildcard "*", if applicable,
+// returning prefix as the part before "*" and suffix as the part after "*".
+func prefixAndSuffix(pattern string) (prefix, suffix string) {
+	if pos := strings.LastIndex(pattern, "*"); pos != -1 {
+		prefix, suffix = pattern[:pos], pattern[pos+1:]
+	} else {
+		prefix = pattern
+	}
+	return
+}
+
+// TempDir creates a new temporary directory in the directory dir.
+// The directory name is generated by taking pattern and applying a
+// random string to the end. If pattern includes a "*", the random string
+// replaces the last "*". TempDir returns the name of the new directory.
+// If dir is the empty string, TempDir uses the
 // default directory for temporary files (see os.TempDir).
 // Multiple programs calling TempDir simultaneously
 // will not choose the same directory. It is the caller's responsibility
 // to remove the directory when no longer needed.
-func TempDir(dir, prefix string) (name string, err error) {
+func TempDir(dir, pattern string) (name string, err error) {
 	if dir == "" {
 		dir = os.TempDir()
 	}
 
+	prefix, suffix := prefixAndSuffix(pattern)
+
 	nconflict := 0
 	for i := 0; i < 10000; i++ {
-		try := filepath.Join(dir, prefix+nextRandom())
+		try := filepath.Join(dir, prefix+nextRandom()+suffix)
 		err = os.Mkdir(try, 0700)
 		if os.IsExist(err) {
 			if nconflict++; nconflict > 10 {
diff --git a/libgo/go/io/ioutil/tempfile_test.go b/libgo/go/io/ioutil/tempfile_test.go
index 0758890..698ebab 100644
--- a/libgo/go/io/ioutil/tempfile_test.go
+++ b/libgo/go/io/ioutil/tempfile_test.go
@@ -54,18 +54,47 @@ func TestTempDir(t *testing.T) {
 		t.Errorf("TempDir(`/_not_exists_`, `foo`) = %v, %v", name, err)
 	}
 
-	dir := os.TempDir()
-	name, err = TempDir(dir, "ioutil_test")
-	if name == "" || err != nil {
-		t.Errorf("TempDir(dir, `ioutil_test`) = %v, %v", name, err)
+	tests := []struct {
+		pattern                string
+		wantPrefix, wantSuffix string
+	}{
+		{"ioutil_test", "ioutil_test", ""},
+		{"ioutil_test*", "ioutil_test", ""},
+		{"ioutil_test*xyz", "ioutil_test", "xyz"},
 	}
-	if name != "" {
-		os.Remove(name)
-		re := regexp.MustCompile("^" + regexp.QuoteMeta(filepath.Join(dir, "ioutil_test")) + "[0-9]+$")
+
+	dir := os.TempDir()
+
+	runTestTempDir := func(t *testing.T, pattern, wantRePat string) {
+		name, err := TempDir(dir, pattern)
+		if name == "" || err != nil {
+			t.Fatalf("TempDir(dir, `ioutil_test`) = %v, %v", name, err)
+		}
+		defer os.Remove(name)
+
+		re := regexp.MustCompile(wantRePat)
 		if !re.MatchString(name) {
-			t.Errorf("TempDir(`"+dir+"`, `ioutil_test`) created bad name %s", name)
+			t.Errorf("TempDir(%q, %q) created bad name\n\t%q\ndid not match pattern\n\t%q", dir, pattern, name, wantRePat)
 		}
 	}
+
+	for _, tt := range tests {
+		t.Run(tt.pattern, func(t *testing.T) {
+			wantRePat := "^" + regexp.QuoteMeta(filepath.Join(dir, tt.wantPrefix)) + "[0-9]+" + regexp.QuoteMeta(tt.wantSuffix) + "$"
+			runTestTempDir(t, tt.pattern, wantRePat)
+		})
+	}
+
+	// Separately testing "*xyz" (which has no prefix). That is when constructing the
+	// pattern to assert on, as in the previous loop, using filepath.Join for an empty
+	// prefix filepath.Join(dir, ""), produces the pattern:
+	//     ^<DIR>[0-9]+xyz$
+	// yet we just want to match
+	//     "^<DIR>/[0-9]+xyz"
+	t.Run("*xyz", func(t *testing.T) {
+		wantRePat := "^" + regexp.QuoteMeta(filepath.Join(dir)) + regexp.QuoteMeta(string(filepath.Separator)) + "[0-9]+xyz$"
+		runTestTempDir(t, "*xyz", wantRePat)
+	})
 }
 
 // test that we return a nice error message if the dir argument to TempDir doesn't
diff --git a/libgo/go/io/multi_test.go b/libgo/go/io/multi_test.go
index 9aad954..bc6b0ab 100644
--- a/libgo/go/io/multi_test.go
+++ b/libgo/go/io/multi_test.go
@@ -287,7 +287,7 @@ func TestMultiReaderSingleByteWithEOF(t *testing.T) {
 	}
 }
 
-// Test that a reader returning (n, EOF) at the end of an MultiReader
+// Test that a reader returning (n, EOF) at the end of a MultiReader
 // chain continues to return EOF on its final read, rather than
 // yielding a (0, EOF).
 func TestMultiReaderFinalEOF(t *testing.T) {
diff --git a/libgo/go/io/pipe.go b/libgo/go/io/pipe.go
index 4efaf2f..b5343bb 100644
--- a/libgo/go/io/pipe.go
+++ b/libgo/go/io/pipe.go
@@ -10,19 +10,26 @@ package io
 import (
 	"errors"
 	"sync"
-	"sync/atomic"
 )
 
-// atomicError is a type-safe atomic value for errors.
-// We use a struct{ error } to ensure consistent use of a concrete type.
-type atomicError struct{ v atomic.Value }
+// onceError is an object that will only store an error once.
+type onceError struct {
+	sync.Mutex // guards following
+	err        error
+}
 
-func (a *atomicError) Store(err error) {
-	a.v.Store(struct{ error }{err})
+func (a *onceError) Store(err error) {
+	a.Lock()
+	defer a.Unlock()
+	if a.err != nil {
+		return
+	}
+	a.err = err
 }
-func (a *atomicError) Load() error {
-	err, _ := a.v.Load().(struct{ error })
-	return err.error
+func (a *onceError) Load() error {
+	a.Lock()
+	defer a.Unlock()
+	return a.err
 }
 
 // ErrClosedPipe is the error used for read or write operations on a closed pipe.
@@ -36,8 +43,8 @@ type pipe struct {
 
 	once sync.Once // Protects closing done
 	done chan struct{}
-	rerr atomicError
-	werr atomicError
+	rerr onceError
+	werr onceError
 }
 
 func (p *pipe) Read(b []byte) (n int, err error) {
@@ -135,6 +142,9 @@ func (r *PipeReader) Close() error {
 
 // CloseWithError closes the reader; subsequent writes
 // to the write half of the pipe will return the error err.
+//
+// CloseWithError never overwrites the previous error if it exists
+// and always returns nil.
 func (r *PipeReader) CloseWithError(err error) error {
 	return r.p.CloseRead(err)
 }
@@ -163,7 +173,8 @@ func (w *PipeWriter) Close() error {
 // read half of the pipe will return no bytes and the error err,
 // or EOF if err is nil.
 //
-// CloseWithError always returns nil.
+// CloseWithError never overwrites the previous error if it exists
+// and always returns nil.
 func (w *PipeWriter) CloseWithError(err error) error {
 	return w.p.CloseWrite(err)
 }
diff --git a/libgo/go/io/pipe_test.go b/libgo/go/io/pipe_test.go
index f18b1c4..8973360 100644
--- a/libgo/go/io/pipe_test.go
+++ b/libgo/go/io/pipe_test.go
@@ -326,8 +326,8 @@ func TestPipeCloseError(t *testing.T) {
 		t.Errorf("Write error: got %T, want testError1", err)
 	}
 	r.CloseWithError(testError2{})
-	if _, err := w.Write(nil); err != (testError2{}) {
-		t.Errorf("Write error: got %T, want testError2", err)
+	if _, err := w.Write(nil); err != (testError1{}) {
+		t.Errorf("Write error: got %T, want testError1", err)
 	}
 
 	r, w = Pipe()
@@ -336,8 +336,8 @@ func TestPipeCloseError(t *testing.T) {
 		t.Errorf("Read error: got %T, want testError1", err)
 	}
 	w.CloseWithError(testError2{})
-	if _, err := r.Read(nil); err != (testError2{}) {
-		t.Errorf("Read error: got %T, want testError2", err)
+	if _, err := r.Read(nil); err != (testError1{}) {
+		t.Errorf("Read error: got %T, want testError1", err)
 	}
 }