cmd/fix, cmd/go, cmd/gofmt: refactor common code into new internal diff package

Change-Id: Idac8473d1752059bf2f617fd7a781000ee2c3af4
GitHub-Last-Rev: 02a3aa1a3241d3ed4422518f1c954cd54bbe858e
GitHub-Pull-Request: golang/go#35141
Reviewed-on: https://go-review.googlesource.com/c/go/+/203218
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/cmd/fix/main.go b/src/cmd/fix/main.go
index f54a5e0d963bf76b14efaf97026ce31d05883733..80b3c76350240be0298183b09ab8f21254d8af69 100644 (file)
--- a/src/cmd/fix/main.go
+++ b/src/cmd/fix/main.go
@@ -15,11 +15,11 @@ import (
        "go/token"
        "io/ioutil"
        "os"
-       "os/exec"
        "path/filepath"
-       "runtime"
        "sort"
        "strings"
+
+       "cmd/internal/diff"
 )
 
 var (
@@ -186,7 +186,7 @@ func processFile(filename string, useStdin bool) error {
        }
 
        if *doDiff {
-               data, err := diff(src, newSrc)
+               data, err := diff.Diff("go-fix", src, newSrc)
                if err != nil {
                        return fmt.Errorf("computing diff: %s", err)
                }
@@ -237,46 +237,3 @@ func isGoFile(f os.FileInfo) bool {
        name := f.Name()
        return !f.IsDir() && !strings.HasPrefix(name, ".") && strings.HasSuffix(name, ".go")
 }
-
-func writeTempFile(dir, prefix string, data []byte) (string, error) {
-       file, err := ioutil.TempFile(dir, prefix)
-       if err != nil {
-               return "", err
-       }
-       _, err = file.Write(data)
-       if err1 := file.Close(); err == nil {
-               err = err1
-       }
-       if err != nil {
-               os.Remove(file.Name())
-               return "", err
-       }
-       return file.Name(), nil
-}
-
-func diff(b1, b2 []byte) (data []byte, err error) {
-       f1, err := writeTempFile("", "go-fix", b1)
-       if err != nil {
-               return
-       }
-       defer os.Remove(f1)
-
-       f2, err := writeTempFile("", "go-fix", b2)
-       if err != nil {
-               return
-       }
-       defer os.Remove(f2)
-
-       cmd := "diff"
-       if runtime.GOOS == "plan9" {
-               cmd = "/bin/ape/diff"
-       }
-
-       data, err = exec.Command(cmd, "-u", f1, f2).CombinedOutput()
-       if len(data) > 0 {
-               // diff exits with a non-zero status when the files don't match.
-               // Ignore that failure as long as we get output.
-               err = nil
-       }
-       return
-}

diff --git a/src/cmd/fix/main_test.go b/src/cmd/fix/main_test.go
index 8868140adefaf568cb558eb98679114777214bb0..ee74f24c6eab4d1c169bd5d8d0ca1e17ac6fdd89 100644 (file)
--- a/src/cmd/fix/main_test.go
+++ b/src/cmd/fix/main_test.go
@@ -9,6 +9,8 @@ import (
        "go/parser"
        "strings"
        "testing"
+
+       "cmd/internal/diff"
 )
 
 type testCase struct {
@@ -123,7 +125,7 @@ func TestRewrite(t *testing.T) {
 }
 
 func tdiff(t *testing.T, a, b string) {
-       data, err := diff([]byte(a), []byte(b))
+       data, err := diff.Diff("go-fix-test", []byte(a), []byte(b))
        if err != nil {
                t.Error(err)
                return

diff --git a/src/cmd/go/internal/modfile/read_test.go b/src/cmd/go/internal/modfile/read_test.go
index 32401304b999f9d82c5bfec59ea0f0030f3b077f..3c88e6928157df3ac909e4c4f8a58f33a9f9a7b6 100644 (file)
--- a/src/cmd/go/internal/modfile/read_test.go
+++ b/src/cmd/go/internal/modfile/read_test.go
@@ -9,11 +9,12 @@ import (
        "fmt"
        "io/ioutil"
        "os"
-       "os/exec"
        "path/filepath"
        "reflect"
        "strings"
        "testing"
+
+       "cmd/internal/diff"
 )
 
 // exists reports whether the named file exists.
@@ -282,37 +283,9 @@ func (eq *eqchecker) checkValue(v, w reflect.Value) error {
        return nil
 }
 
-// diff returns the output of running diff on b1 and b2.
-func diff(b1, b2 []byte) (data []byte, err error) {
-       f1, err := ioutil.TempFile("", "testdiff")
-       if err != nil {
-               return nil, err
-       }
-       defer os.Remove(f1.Name())
-       defer f1.Close()
-
-       f2, err := ioutil.TempFile("", "testdiff")
-       if err != nil {
-               return nil, err
-       }
-       defer os.Remove(f2.Name())
-       defer f2.Close()
-
-       f1.Write(b1)
-       f2.Write(b2)
-
-       data, err = exec.Command("diff", "-u", f1.Name(), f2.Name()).CombinedOutput()
-       if len(data) > 0 {
-               // diff exits with a non-zero status when the files don't match.
-               // Ignore that failure as long as we get output.
-               err = nil
-       }
-       return
-}
-
 // tdiff logs the diff output to t.Error.
 func tdiff(t *testing.T, a, b string) {
-       data, err := diff([]byte(a), []byte(b))
+       data, err := diff.Diff("modfile-test", []byte(a), []byte(b))
        if err != nil {
                t.Error(err)
                return

diff --git a/src/cmd/gofmt/gofmt.go b/src/cmd/gofmt/gofmt.go
index d7a77a968231ca477c3fb1423c6f58c7c6b76099..9e472b2d51c0ba89a8cf0f0bc6d386d969ada84d 100644 (file)
--- a/src/cmd/gofmt/gofmt.go
+++ b/src/cmd/gofmt/gofmt.go
@@ -16,11 +16,12 @@ import (
        "io"
        "io/ioutil"
        "os"
-       "os/exec"
        "path/filepath"
        "runtime"
        "runtime/pprof"
        "strings"
+
+       "cmd/internal/diff"
 )
 
 var (
@@ -141,7 +142,7 @@ func processFile(filename string, in io.Reader, out io.Writer, stdin bool) error
                        }
                }
                if *doDiff {
-                       data, err := diff(src, res, filename)
+                       data, err := diffWithReplaceTempFile(src, res, filename)
                        if err != nil {
                                return fmt.Errorf("computing diff: %s", err)
                        }
@@ -227,47 +228,12 @@ func gofmtMain() {
        }
 }
 
-func writeTempFile(dir, prefix string, data []byte) (string, error) {
-       file, err := ioutil.TempFile(dir, prefix)
-       if err != nil {
-               return "", err
-       }
-       _, err = file.Write(data)
-       if err1 := file.Close(); err == nil {
-               err = err1
-       }
-       if err != nil {
-               os.Remove(file.Name())
-               return "", err
-       }
-       return file.Name(), nil
-}
-
-func diff(b1, b2 []byte, filename string) (data []byte, err error) {
-       f1, err := writeTempFile("", "gofmt", b1)
-       if err != nil {
-               return
-       }
-       defer os.Remove(f1)
-
-       f2, err := writeTempFile("", "gofmt", b2)
-       if err != nil {
-               return
-       }
-       defer os.Remove(f2)
-
-       cmd := "diff"
-       if runtime.GOOS == "plan9" {
-               cmd = "/bin/ape/diff"
-       }
-
-       data, err = exec.Command(cmd, "-u", f1, f2).CombinedOutput()
+func diffWithReplaceTempFile(b1, b2 []byte, filename string) ([]byte, error) {
+       data, err := diff.Diff("gofmt", b1, b2)
        if len(data) > 0 {
-               // diff exits with a non-zero status when the files don't match.
-               // Ignore that failure as long as we get output.
                return replaceTempFilename(data, filename)
        }
-       return
+       return data, err
 }
 
 // replaceTempFilename replaces temporary filenames in diff with actual one.

diff --git a/src/cmd/gofmt/gofmt_test.go b/src/cmd/gofmt/gofmt_test.go
index 3008365cd237ca4ac4513a370b51dd326292ad0c..98d3eb7eb27b3618475e6fab84e77e7643214278 100644 (file)
--- a/src/cmd/gofmt/gofmt_test.go
+++ b/src/cmd/gofmt/gofmt_test.go
@@ -112,7 +112,7 @@ func runTest(t *testing.T, in, out string) {
                }
 
                t.Errorf("(gofmt %s) != %s (see %s.gofmt)", in, out, in)
-               d, err := diff(expected, got, in)
+               d, err := diffWithReplaceTempFile(expected, got, in)
                if err == nil {
                        t.Errorf("%s", d)
                }
@@ -194,7 +194,7 @@ func TestDiff(t *testing.T) {
        in := []byte("first\nsecond\n")
        out := []byte("first\nthird\n")
        filename := "difftest.txt"
-       b, err := diff(in, out, filename)
+       b, err := diffWithReplaceTempFile(in, out, filename)
        if err != nil {
                t.Fatal(err)
        }

diff --git a/src/cmd/internal/diff/diff.go b/src/cmd/internal/diff/diff.go
new file mode 100644 (file)
index 0000000..e9d2c23
--- /dev/null
+++ b/src/cmd/internal/diff/diff.go
@@ -0,0 +1,58 @@
+// Copyright 2019 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 diff implements a Diff function that compare two inputs
+// using the 'diff' tool.
+package diff
+
+import (
+       "io/ioutil"
+       "os"
+       "os/exec"
+       "runtime"
+)
+
+// Returns diff of two arrays of bytes in diff tool format.
+func Diff(prefix string, b1, b2 []byte) ([]byte, error) {
+       f1, err := writeTempFile(prefix, b1)
+       if err != nil {
+               return nil, err
+       }
+       defer os.Remove(f1)
+
+       f2, err := writeTempFile(prefix, b2)
+       if err != nil {
+               return nil, err
+       }
+       defer os.Remove(f2)
+
+       cmd := "diff"
+       if runtime.GOOS == "plan9" {
+               cmd = "/bin/ape/diff"
+       }
+
+       data, err := exec.Command(cmd, "-u", f1, f2).CombinedOutput()
+       if len(data) > 0 {
+               // diff exits with a non-zero status when the files don't match.
+               // Ignore that failure as long as we get output.
+               err = nil
+       }
+       return data, err
+}
+
+func writeTempFile(prefix string, data []byte) (string, error) {
+       file, err := ioutil.TempFile("", prefix)
+       if err != nil {
+               return "", err
+       }
+       _, err = file.Write(data)
+       if err1 := file.Close(); err == nil {
+               err = err1
+       }
+       if err != nil {
+               os.Remove(file.Name())
+               return "", err
+       }
+       return file.Name(), nil
+}