start to implement gokcehan#1784, set shell as template for CMD on Wi…

…ndows

- make `tokenize` to honor quotes
- create function `firstField` to get only the first word from string
- SlellCommand in os_windows.go now handles new type of gOpts.shell for example:
`set shell 'cmd /c "%c %a"'`
- tests for cmd.exe

misc.go

@@ -107,9 +107,55 @@ func unescape(s string) string {
 	return string(buf)
 }
 
+type fieldScanner struct {
+	quoted bool
+	esc    bool
+}
+
+func (t *fieldScanner) next(r rune) bool {
+	if r == '\'' || r == '"' || r == '`' {
+		t.quoted = !t.quoted
+	}
+	if t.esc {
+		t.esc = false
+		return false
+	}
+	if r == '\\' {
+		t.esc = true
+		return false
+	}
+	return !t.quoted && unicode.IsSpace(r)
+}
+
+func firstField(s string) (int, int) {
+	t := &fieldScanner{}
+	start := -1
+	for end, rune := range s {
+		if t.next(rune) {
+			if start >= 0 {
+				return start, end
+			}
+		} else {
+			if start < 0 {
+				start = end
+			}
+		}
+	}
+	return start, len(s)
+}
+
 // This function splits the given string by whitespaces. It is aware of escaped
-// whitespaces so that they are not split unintentionally.
+// whitespaces and quoted strings so that they are not split unintentionally.
 func tokenize(s string) []string {
+	t := &fieldScanner{}
+	toks := strings.FieldsFunc(s, t.next)
+	if len(toks) == 0 {
+		toks = append(toks, s)
+	}
+	return toks
+}
+
+func tokenize_old(s string) []string {
 	esc := false
 	var buf []rune
 	var toks []string

misc_test.go

@@ -188,7 +188,7 @@ func TestTokenize(t *testing.T) {
 
 	for _, test := range tests {
 		if got := tokenize(test.s); !reflect.DeepEqual(got, test.exp) {
-			t.Errorf("at input '%v' expected '%v' but got '%v'", test.s, test.exp, got)
+			t.Errorf("at input '%#v' expected '%#v' but got '%#v'", test.s, test.exp, got)
 		}
 	}
 }

os_windows.go

@@ -119,6 +119,21 @@ func detachedCommand(name string, arg ...string) *exec.Cmd {
 }
 
 func shellCommand(s string, args []string) *exec.Cmd {
+	if strings.Contains(gOpts.shell, " ") {
+		start, end := firstField(gOpts.shell)
+		cmd := exec.Command(gOpts.shell[start:end])
+		cmd.Args = nil
+		cmdLine := syscall.EscapeArg(cmd.Path) + " " + gOpts.shell[end:]
+
+		cmdLine = strings.ReplaceAll(cmdLine, "%c", s)
+		cmdLine = strings.ReplaceAll(cmdLine, "%a", strings.Join(args, " "))
+
+		cmd.SysProcAttr = &syscall.SysProcAttr{
+			CmdLine: cmdLine,
+		}
+		return cmd
+
+	}
 	// Windows CMD requires special handling to deal with quoted arguments
 	if strings.ToLower(gOpts.shell) == "cmd" {
 		var builder strings.Builder

os_windows_test.go

@@ -0,0 +1,92 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"reflect"
+	"testing"
+)
+
+
+func TestFirst(t *testing.T) {
+	tests := []struct {
+		in  string
+		out string
+	}{
+		{"cmd", "cmd"},
+		{"cmd /c", "cmd"},
+		{`"C:\Program Files\echo.bat" hello world`, `"C:\Program Files\echo.bat"`},
+		{`ec\ ho -c "sdsd" 1 2 3`, `ec\ ho`},
+	}
+
+	for _, test := range tests {
+		start, end := firstField(test.in)
+		r := test.in[start:end]
+		if !reflect.DeepEqual(r, test.out) {
+			t.Errorf("at input '%#v' expected '%#v' but parsed '%#v'", test.in, test.out, r)
+		}
+	}
+}
+
+func setup(_ *testing.T) (string, func(_ *testing.T)) {
+	tmpDir, err := os.MkdirTemp("", "lfTestShellCommand")
+	if err != nil {
+		panic(err)
+	}
+	wd, err := os.Getwd()
+	_ = wd
+	if err != nil {
+		panic(err)
+	}
+	os.Chdir(tmpDir)
+
+	// Return a function to teardown the test
+	return tmpDir, func(t *testing.T) {
+		os.Chdir(wd)
+		os.RemoveAll(tmpDir)
+	}
+}
+
+func TestShellCommand_Cmd(t *testing.T) {
+	tmpDir, teardown := setup(t)
+	defer teardown(t)
+
+	shell := `cmd.exe /c "%c %a"`
+	gOpts.shell = shell
+
+	run := func(c string, a []string) {
+		cmd := shellCommand( c, a)
+		cmd.Stdout = os.Stdout
+		cmd.Stderr = os.Stderr
+		err := cmd.Run()
+		if err != nil {
+			t.Errorf("failed to run command '%#v' with args '%#v' %v", c, a, err)
+		}
+	}
+
+	tmpBat := filepath.Join(tmpDir, "Test Folder With Spaces", "echo.bat")
+	os.MkdirAll(filepath.Dir(tmpBat), os.ModePerm)
+	f, err := os.Create(tmpBat)
+	if err != nil {
+		panic(err)
+	}
+	defer f.Close()
+
+	_, err = f.WriteString(`
+ECHO script args: %0 %*
+
+`)
+	if err != nil {
+		panic(err)
+	}
+	run(fmt.Sprintf(`"%s"`, tmpBat), []string{`hello friend`})
+
+	run(fmt.Sprintf(`dir "%s\Test Folder With Spaces" | %%PAGER%%`, tmpDir), []string{})
+
+	c := `mkdir "foo bar"`
+	run(c, []string{})
+	if stat, err := os.Stat("foo bar"); err != nil || !stat.IsDir() {
+		t.Errorf("failed to run command '%#v' %v", c, err)
+	}
+}