path/filepath: Simplify Walk interface

The last argument of filepath.Walk was removed, and the Visitor
interface now contains an Error method that is called on errors.

Fixes #2237.

R=golang-dev, gri, r
CC=golang-dev
https://golang.org/cl/4964067

diff --git a/src/cmd/gofix/main.go b/src/cmd/gofix/main.go
index e7e7013c568b6eefe5f17ddba806a10529fe394a..514bf38edbc8a58f8b18ef0ebea3fb880003929a 100644 (file)
--- a/src/cmd/gofix/main.go
+++ b/src/cmd/gofix/main.go
@@ -200,7 +200,7 @@ func report(err os.Error) {
 func walkDir(path string) {
        v := make(fileVisitor)
        go func() {
-               filepath.Walk(path, v, v)
+               filepath.Walk(path, v)
                close(v)
        }()
        for err := range v {
@@ -225,6 +225,10 @@ func (v fileVisitor) VisitFile(path string, f *os.FileInfo) {
        }
 }
 
+func (v fileVisitor) Error(path string, err os.Error) {
+       v <- err
+}
+
 func isGoFile(f *os.FileInfo) bool {
        // ignore non-Go files
        return f.IsRegular() && !strings.HasPrefix(f.Name, ".") && strings.HasSuffix(f.Name, ".go")

diff --git a/src/cmd/gofmt/gofmt.go b/src/cmd/gofmt/gofmt.go
index 975ae6ac6f5807e5a819f3beb0073b4a9999e322..1225618031d8c64afc10a7bbc0f46aa09f86df11 100644 (file)
--- a/src/cmd/gofmt/gofmt.go
+++ b/src/cmd/gofmt/gofmt.go
@@ -164,10 +164,14 @@ func (v fileVisitor) VisitFile(path string, f *os.FileInfo) {
        }
 }
 
+func (v fileVisitor) Error(path string, err os.Error) {
+       v <- err
+}
+
 func walkDir(path string) {
        v := make(fileVisitor)
        go func() {
-               filepath.Walk(path, v, v)
+               filepath.Walk(path, v)
                close(v)
        }()
        for err := range v {

diff --git a/src/cmd/govet/govet.go b/src/cmd/govet/govet.go
index 98d3d5c17f0c0773c3903052de3dcbdcdc024c7b..c53515d3bfd9567af09f6f77ba5f51a623c7fb65 100644 (file)
--- a/src/cmd/govet/govet.go
+++ b/src/cmd/govet/govet.go
@@ -104,30 +104,34 @@ func doFile(name string, reader io.Reader) {
 // Visitor for filepath.Walk - trivial.  Just calls doFile on each file.
 // TODO: if govet becomes richer, might want to process
 // a directory (package) at a time.
-type V struct{}
+type fileVisitor chan os.Error
 
-func (v V) VisitDir(path string, f *os.FileInfo) bool {
+func (v fileVisitor) VisitDir(path string, f *os.FileInfo) bool {
        return true
 }
 
-func (v V) VisitFile(path string, f *os.FileInfo) {
+func (v fileVisitor) VisitFile(path string, f *os.FileInfo) {
        if strings.HasSuffix(path, ".go") {
                doFile(path, nil)
        }
 }
 
+func (v fileVisitor) Error(path string, err os.Error) {
+       v <- err
+}
+
 // walkDir recursively walks the tree looking for .go files.
 func walkDir(root string) {
-       errors := make(chan os.Error)
+       v := make(fileVisitor)
        done := make(chan bool)
        go func() {
-               for e := range errors {
+               for e := range v {
                        errorf("walk error: %s", e)
                }
                done <- true
        }()
-       filepath.Walk(root, V{}, errors)
-       close(errors)
+       filepath.Walk(root, v)
+       close(v)
        <-done
 }
 

diff --git a/src/pkg/path/filepath/path.go b/src/pkg/path/filepath/path.go
index 3d5b915c1013641049ef592e9fbc5a213397f6eb..d6a7d08e83ca0427913adc19b6707b3474194250 100644 (file)
--- a/src/pkg/path/filepath/path.go
+++ b/src/pkg/path/filepath/path.go
@@ -255,14 +255,14 @@ func Abs(path string) (string, os.Error) {
 }
 
 // Visitor methods are invoked for corresponding file tree entries
-// visited by Walk. The parameter path is the full path of f relative
-// to root.
+// visited by Walk.
 type Visitor interface {
        VisitDir(path string, f *os.FileInfo) bool
        VisitFile(path string, f *os.FileInfo)
+       Error(path string, err os.Error)
 }
 
-func walk(path string, f *os.FileInfo, v Visitor, errors chan<- os.Error) {
+func walk(path string, f *os.FileInfo, v Visitor) {
        if !f.IsDirectory() {
                v.VisitFile(path, f)
                return
@@ -274,13 +274,11 @@ func walk(path string, f *os.FileInfo, v Visitor, errors chan<- os.Error) {
 
        list, err := readDir(path)
        if err != nil {
-               if errors != nil {
-                       errors <- err
-               }
+               v.Error(path, err)
        }
 
        for _, e := range list {
-               walk(Join(path, e.Name), e, v, errors)
+               walk(Join(path, e.Name), e, v)
        }
 }
 
@@ -316,18 +314,14 @@ func (f fileInfoList) Swap(i, j int)      { f[i], f[j] = f[j], f[i] }
 // v.VisitFile for each directory or file in the tree, including root.
 // If v.VisitDir returns false, Walk skips the directory's entries;
 // otherwise it invokes itself for each directory entry in sorted order.
-// An error reading a directory does not abort the Walk.
-// If errors != nil, Walk sends each directory read error
-// to the channel.  Otherwise Walk discards the error.
-func Walk(root string, v Visitor, errors chan<- os.Error) {
+// Walk calls v.Error if an error happens while reading a directory.
+func Walk(root string, v Visitor) {
        f, err := os.Lstat(root)
        if err != nil {
-               if errors != nil {
-                       errors <- err
-               }
+               v.Error(root, err)
                return // can't progress
        }
-       walk(root, f, v, errors)
+       walk(root, f, v)
 }
 
 // Base returns the last element of path.

diff --git a/src/pkg/path/filepath/path_test.go b/src/pkg/path/filepath/path_test.go
index 395b12775a9ed62c4854e9b4aace65efee29afba..8c566c700259ef2501daaf660c05357bacbd1d3a 100644 (file)
--- a/src/pkg/path/filepath/path_test.go
+++ b/src/pkg/path/filepath/path_test.go
@@ -299,30 +299,30 @@ func mark(name string) {
        })
 }
 
-type TestVisitor struct{}
+type TestVisitor chan os.Error
 
-func (v *TestVisitor) VisitDir(path string, f *os.FileInfo) bool {
+func (v TestVisitor) VisitDir(path string, f *os.FileInfo) bool {
        mark(f.Name)
        return true
 }
 
-func (v *TestVisitor) VisitFile(path string, f *os.FileInfo) {
+func (v TestVisitor) VisitFile(path string, f *os.FileInfo) {
        mark(f.Name)
 }
 
+func (v TestVisitor) Error(path string, err os.Error) {
+       v <- err
+}
+
 func TestWalk(t *testing.T) {
        makeTree(t)
 
-       // 1) ignore error handling, expect none
-       v := &TestVisitor{}
-       filepath.Walk(tree.name, v, nil)
-       checkMarks(t)
+       v := make(TestVisitor, 64)
 
-       // 2) handle errors, expect none
-       errors := make(chan os.Error, 64)
-       filepath.Walk(tree.name, v, errors)
+       // 1) no errors expected.
+       filepath.Walk(tree.name, v)
        select {
-       case err := <-errors:
+       case err := <-v:
                t.Errorf("no error expected, found: %s", err)
        default:
                // ok
@@ -343,14 +343,13 @@ func TestWalk(t *testing.T) {
                tree.entries[1].mark--
                tree.entries[3].mark--
 
-               // 3) handle errors, expect two
-               errors = make(chan os.Error, 64)
+               // 2) expect two errors
                os.Chmod(filepath.Join(tree.name, tree.entries[1].name), 0)
-               filepath.Walk(tree.name, v, errors)
+               filepath.Walk(tree.name, v)
        Loop:
                for i := 1; i <= 2; i++ {
                        select {
-                       case <-errors:
+                       case <-v:
                                // ok
                        default:
                                t.Errorf("%d. error expected, none found", i)
@@ -358,7 +357,7 @@ func TestWalk(t *testing.T) {
                        }
                }
                select {
-               case err := <-errors:
+               case err := <-v:
                        t.Errorf("only two errors expected, found 3rd: %v", err)
                default:
                        // ok