diff options
Diffstat (limited to 'libgo/go/cmd/internal/diff/diff.go')
-rw-r--r-- | libgo/go/cmd/internal/diff/diff.go | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/libgo/go/cmd/internal/diff/diff.go b/libgo/go/cmd/internal/diff/diff.go new file mode 100644 index 00000000000..e9d2c237800 --- /dev/null +++ b/libgo/go/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 +} |