feat(third_party): Check in git-appraise

third_party/go/git-appraise/commands/input/input.go

@@ -0,0 +1,118 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package input
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"github.com/google/git-appraise/repository"
+	"io/ioutil"
+	"os"
+	"os/exec"
+)
+
+// LaunchEditor launches the default editor configured for the given repo. This
+// method blocks until the editor command has returned.
+//
+// The specified filename should be a temporary file and provided as a relative path
+// from the repo (e.g. "FILENAME" will be converted to ".git/FILENAME"). This file
+// will be deleted after the editor is closed and its contents have been read.
+//
+// This method returns the text that was read from the temporary file, or
+// an error if any step in the process failed.
+func LaunchEditor(repo repository.Repo, fileName string) (string, error) {
+	editor, err := repo.GetCoreEditor()
+	if err != nil {
+		return "", fmt.Errorf("Unable to detect default git editor: %v\n", err)
+	}
+
+	path := fmt.Sprintf("%s/.git/%s", repo.GetPath(), fileName)
+
+	cmd, err := startInlineCommand(editor, path)
+	if err != nil {
+		// Running the editor directly did not work. This might mean that
+		// the editor string is not a path to an executable, but rather
+		// a shell command (e.g. "emacsclient --tty"). As such, we'll try
+		// to run the command through bash, and if that fails, try with sh
+		args := []string{"-c", fmt.Sprintf("%s %q", editor, path)}
+		cmd, err = startInlineCommand("bash", args...)
+		if err != nil {
+			cmd, err = startInlineCommand("sh", args...)
+		}
+	}
+	if err != nil {
+		return "", fmt.Errorf("Unable to start editor: %v\n", err)
+	}
+
+	if err := cmd.Wait(); err != nil {
+		return "", fmt.Errorf("Editing finished with error: %v\n", err)
+	}
+
+	output, err := ioutil.ReadFile(path)
+	if err != nil {
+		os.Remove(path)
+		return "", fmt.Errorf("Error reading edited file: %v\n", err)
+	}
+	os.Remove(path)
+	return string(output), err
+}
+
+// FromFile loads and returns the contents of a given file. If - is passed
+// through, much like git, it will read from stdin. This can be piped data,
+// unless there is a tty in which case the user will be prompted to enter a
+// message.
+func FromFile(fileName string) (string, error) {
+	if fileName == "-" {
+		stat, err := os.Stdin.Stat()
+		if err != nil {
+			return "", fmt.Errorf("Error reading from stdin: %v\n", err)
+		}
+		if (stat.Mode() & os.ModeCharDevice) == 0 {
+			// There is no tty. This will allow us to read piped data instead.
+			output, err := ioutil.ReadAll(os.Stdin)
+			if err != nil {
+				return "", fmt.Errorf("Error reading from stdin: %v\n", err)
+			}
+			return string(output), err
+		}
+
+		fmt.Printf("(reading comment from standard input)\n")
+		var output bytes.Buffer
+		s := bufio.NewScanner(os.Stdin)
+		for s.Scan() {
+			output.Write(s.Bytes())
+			output.WriteRune('\n')
+		}
+		return output.String(), nil
+	}
+
+	output, err := ioutil.ReadFile(fileName)
+	if err != nil {
+		return "", fmt.Errorf("Error reading file: %v\n", err)
+	}
+	return string(output), err
+}
+
+func startInlineCommand(command string, args ...string) (*exec.Cmd, error) {
+	cmd := exec.Command(command, args...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	err := cmd.Start()
+	return cmd, err
+}