Add --with-shell for shelling out with different command and flags (#3746)

Close #3732

2 files changed, 122 insertions, 40 deletions

diff --git a/src/util/util_unix.go b/src/util/util_unix.go
index 2991fd2c..4410a9bf 100644
--- a/src/util/util_unix.go
+++ b/src/util/util_unix.go
@@ -3,31 +3,71 @@
 package util
 
 import (
+	"fmt"
 	"os"
 	"os/exec"
+	"strings"
 	"syscall"
 
 	"golang.org/x/sys/unix"
 )
 
-// ExecCommand executes the given command with $SHELL
-func ExecCommand(command string, setpgid bool) *exec.Cmd {
+type Executor struct {
+	shell   string
+	args    []string
+	escaper *strings.Replacer
+}
+
+func NewExecutor(withShell string) *Executor {
 	shell := os.Getenv("SHELL")
-	if len(shell) == 0 {
-		shell = "sh"
+	args := strings.Fields(withShell)
+	if len(args) > 0 {
+		shell = args[0]
+		args = args[1:]
+	} else {
+		if len(shell) == 0 {
+			shell = "sh"
+		}
+		args = []string{"-c"}
 	}
-	return ExecCommandWith(shell, command, setpgid)
+
+	var escaper *strings.Replacer
+	tokens := strings.Split(shell, "/")
+	if tokens[len(tokens)-1] == "fish" {
+		// https://fishshell.com/docs/current/language.html#quotes
+		// > The only meaningful escape sequences in single quotes are \', which
+		// > escapes a single quote and \\, which escapes the backslash symbol.
+		escaper = strings.NewReplacer("\\", "\\\\", "'", "\\'")
+	} else {
+		escaper = strings.NewReplacer("'", "'\\''")
+	}
+	return &Executor{shell, args, escaper}
 }
 
-// ExecCommandWith executes the given command with the specified shell
-func ExecCommandWith(shell string, command string, setpgid bool) *exec.Cmd {
-	cmd := exec.Command(shell, "-c", command)
+// ExecCommand executes the given command with $SHELL
+func (x *Executor) ExecCommand(command string, setpgid bool) *exec.Cmd {
+	cmd := exec.Command(x.shell, append(x.args, command)...)
 	if setpgid {
 		cmd.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
 	}
 	return cmd
 }
 
+func (x *Executor) QuoteEntry(entry string) string {
+	return "'" + x.escaper.Replace(entry) + "'"
+}
+
+func (x *Executor) Become(stdin *os.File, environ []string, command string) {
+	shellPath, err := exec.LookPath(x.shell)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "fzf (become): %s\n", err.Error())
+		Exit(127)
+	}
+	args := append([]string{shellPath}, append(x.args, command)...)
+	SetStdin(stdin)
+	syscall.Exec(shellPath, args, environ)
+}
+
 // KillCommand kills the process for the given command
 func KillCommand(cmd *exec.Cmd) error {
 	return syscall.Kill(-cmd.Process.Pid, syscall.SIGKILL)
diff --git a/src/util/util_windows.go b/src/util/util_windows.go
index aa69b99d..cbaa8ce0 100644
--- a/src/util/util_windows.go
+++ b/src/util/util_windows.go
@@ -6,60 +6,102 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"regexp"
 	"strings"
 	"sync/atomic"
 	"syscall"
 )
 
-var shellPath atomic.Value
+type Executor struct {
+	shell     string
+	args      []string
+	shellPath atomic.Value
+}
+
+func NewExecutor(withShell string) *Executor {
+	shell := os.Getenv("SHELL")
+	args := strings.Fields(withShell)
+	if len(args) > 0 {
+		shell = args[0]
+	} else if len(shell) == 0 {
+		shell = "cmd"
+	}
+
+	if len(args) > 0 {
+		args = args[1:]
+	} else if strings.Contains(shell, "cmd") {
+		args = []string{"/v:on/s/c"}
+	} else if strings.Contains(shell, "pwsh") || strings.Contains(shell, "powershell") {
+		args = []string{"-NoProfile", "-Command"}
+	} else {
+		args = []string{"-c"}
+	}
+	return &Executor{shell: shell, args: args}
+}
 
 // ExecCommand executes the given command with $SHELL
-func ExecCommand(command string, setpgid bool) *exec.Cmd {
-	var shell string
-	if cached := shellPath.Load(); cached != nil {
+// FIXME: setpgid is unused. We set it in the Unix implementation so that we
+// can kill preview process with its child processes at once.
+// NOTE: For "powershell", we should ideally set output encoding to UTF8,
+// but it is left as is now because no adverse effect has been observed.
+func (x *Executor) ExecCommand(command string, setpgid bool) *exec.Cmd {
+	shell := x.shell
+	if cached := x.shellPath.Load(); cached != nil {
 		shell = cached.(string)
 	} else {
-		shell = os.Getenv("SHELL")
-		if len(shell) == 0 {
-			shell = "cmd"
-		} else if strings.Contains(shell, "/") {
+		if strings.Contains(shell, "/") {
 			out, err := exec.Command("cygpath", "-w", shell).Output()
 			if err == nil {
 				shell = strings.Trim(string(out), "\n")
 			}
 		}
-		shellPath.Store(shell)
+		x.shellPath.Store(shell)
 	}
-	return ExecCommandWith(shell, command, setpgid)
+	cmd := exec.Command(shell, append(x.args, command)...)
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		HideWindow:    false,
+		CreationFlags: 0,
+	}
+	return cmd
 }
 
-// ExecCommandWith executes the given command with the specified shell
-// FIXME: setpgid is unused. We set it in the Unix implementation so that we
-// can kill preview process with its child processes at once.
-// NOTE: For "powershell", we should ideally set output encoding to UTF8,
-// but it is left as is now because no adverse effect has been observed.
-func ExecCommandWith(shell string, command string, setpgid bool) *exec.Cmd {
-	var cmd *exec.Cmd
-	if strings.Contains(shell, "cmd") {
-		cmd = exec.Command(shell)
-		cmd.SysProcAttr = &syscall.SysProcAttr{
-			HideWindow:    false,
-			CmdLine:       fmt.Sprintf(` /v:on/s/c "%s"`, command),
-			CreationFlags: 0,
+func (x *Executor) Become(stdin *os.File, environ []string, command string) {
+	cmd := x.ExecCommand(command, false)
+	cmd.Stdin = stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	cmd.Env = environ
+	err := cmd.Start()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "fzf (become): %s\n", err.Error())
+		Exit(127)
+	}
+	err = cmd.Wait()
+	if err != nil {
+		if exitError, ok := err.(*exec.ExitError); ok {
+			Exit(exitError.ExitCode())
 		}
-		return cmd
 	}
+	Exit(0)
+}
 
-	if strings.Contains(shell, "pwsh") || strings.Contains(shell, "powershell") {
-		cmd = exec.Command(shell, "-NoProfile", "-Command", command)
+func (x *Executor) QuoteEntry(entry string) string {
+	if strings.Contains(x.shell, "cmd") {
+		// backslash escaping is done here for applications
+		// (see ripgrep test case in terminal_test.go#TestWindowsCommands)
+		escaped := strings.Replace(entry, `\`, `\\`, -1)
+		escaped = `"` + strings.Replace(escaped, `"`, `\"`, -1) + `"`
+		// caret is the escape character for cmd shell
+		r, _ := regexp.Compile(`[&|<>()@^%!"]`)
+		return r.ReplaceAllStringFunc(escaped, func(match string) string {
+			return "^" + match
+		})
+	} else if strings.Contains(x.shell, "pwsh") || strings.Contains(x.shell, "powershell") {
+		escaped := strings.Replace(entry, `"`, `\"`, -1)
+		return "'" + strings.Replace(escaped, "'", "''", -1) + "'"
 	} else {
-		cmd = exec.Command(shell, "-c", command)
-	}
-	cmd.SysProcAttr = &syscall.SysProcAttr{
-		HideWindow:    false,
-		CreationFlags: 0,
+		return "'" + strings.Replace(entry, "'", "'\\''", -1) + "'"
 	}
-	return cmd
 }
 
 // KillCommand kills the process for the given command