git: port the implementation of alias "git-sw" to Golang

1 files changed, 47 insertions, 0 deletions

diff --git a/src/gitalias/git-sw.go b/src/gitalias/git-sw.go
new file mode 100644
index 0000000..f4cab21
--- /dev/null
+++ b/src/gitalias/git-sw.go
@@ -0,0 +1,47 @@
+package main
+
+import (
+	"log"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+func main() {
+	gitArgs := []string{"switch"}
+	if requiresDetachFlag(os.Args) {
+		gitArgs = append(gitArgs, "--detach")
+	}
+	for i, argv := range os.Args {
+		if i == 0 {
+			continue // argv[0] is a program name.
+		}
+		gitArgs = append(gitArgs, argv)
+	}
+
+	cmd := exec.Command("git", gitArgs...)
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	err := cmd.Run()
+	if err != nil {
+		switch err.(type) {
+		case *exec.ExitError:
+			// Do nothing here because Git has already reported the error.
+		default:
+			log.Fatal(err)
+		}
+	}
+
+	os.Exit(cmd.ProcessState.ExitCode())
+}
+
+func requiresDetachFlag(argv []string) bool {
+	argc := len(argv)
+	if argc == 1 {
+		return false
+	}
+	firstArg := argv[1]
+	return strings.HasPrefix(firstArg, "origin/") || strings.HasPrefix(firstArg, "upstream/")
+}