1use crate::shell::get_system_shell;
2use crate::shell::{Shell, ShellKind};
3
4/// ShellBuilder is used to turn a user-requested task into a
5/// program that can be executed by the shell.
6pub struct ShellBuilder {
7 /// The shell to run
8 program: String,
9 args: Vec<String>,
10 interactive: bool,
11 /// Whether to redirect stdin to /dev/null for the spawned command as a subshell.
12 redirect_stdin: bool,
13 kind: ShellKind,
14}
15
16impl ShellBuilder {
17 /// Create a new ShellBuilder as configured.
18 pub fn new(shell: &Shell, is_windows: bool) -> Self {
19 let (program, args) = match shell {
20 Shell::System => (get_system_shell(), Vec::new()),
21 Shell::Program(shell) => (shell.clone(), Vec::new()),
22 Shell::WithArguments { program, args, .. } => (program.clone(), args.clone()),
23 };
24
25 let kind = ShellKind::new(&program, is_windows);
26 Self {
27 program,
28 args,
29 interactive: true,
30 kind,
31 redirect_stdin: false,
32 }
33 }
34 pub fn non_interactive(mut self) -> Self {
35 self.interactive = false;
36 self
37 }
38
39 /// Returns the label to show in the terminal tab
40 pub fn command_label(&self, command_to_use_in_label: &str) -> String {
41 if command_to_use_in_label.trim().is_empty() {
42 self.program.clone()
43 } else {
44 match self.kind {
45 ShellKind::PowerShell => {
46 format!("{} -C '{}'", self.program, command_to_use_in_label)
47 }
48 ShellKind::Cmd => {
49 format!("{} /C \"{}\"", self.program, command_to_use_in_label)
50 }
51 ShellKind::Posix
52 | ShellKind::Nushell
53 | ShellKind::Fish
54 | ShellKind::Csh
55 | ShellKind::Tcsh
56 | ShellKind::Rc
57 | ShellKind::Xonsh => {
58 let interactivity = self.interactive.then_some("-i ").unwrap_or_default();
59 format!(
60 "{PROGRAM} {interactivity}-c '{command_to_use_in_label}'",
61 PROGRAM = self.program
62 )
63 }
64 }
65 }
66 }
67
68 pub fn redirect_stdin_to_dev_null(mut self) -> Self {
69 self.redirect_stdin = true;
70 self
71 }
72
73 /// Returns the program and arguments to run this task in a shell.
74 pub fn build(
75 mut self,
76 task_command: Option<String>,
77 task_args: &[String],
78 ) -> (String, Vec<String>) {
79 if let Some(task_command) = task_command {
80 let mut combined_command = task_args.iter().fold(task_command, |mut command, arg| {
81 command.push(' ');
82 command.push_str(&self.kind.to_shell_variable(arg));
83 command
84 });
85 if self.redirect_stdin {
86 match self.kind {
87 ShellKind::Fish => {
88 combined_command.insert_str(0, "begin; ");
89 combined_command.push_str("; end </dev/null");
90 }
91 ShellKind::Posix
92 | ShellKind::Nushell
93 | ShellKind::Csh
94 | ShellKind::Tcsh
95 | ShellKind::Rc
96 | ShellKind::Xonsh => {
97 combined_command.insert(0, '(');
98 combined_command.push_str(") </dev/null");
99 }
100 ShellKind::PowerShell => {
101 combined_command.insert_str(0, "$null | & {");
102 combined_command.push_str("}");
103 }
104 ShellKind::Cmd => {
105 combined_command.push_str("< NUL");
106 }
107 }
108 }
109
110 self.args
111 .extend(self.kind.args_for_shell(self.interactive, combined_command));
112 }
113
114 (self.program, self.args)
115 }
116}
117
118#[cfg(test)]
119mod test {
120 use super::*;
121
122 #[test]
123 fn test_nu_shell_variable_substitution() {
124 let shell = Shell::Program("nu".to_owned());
125 let shell_builder = ShellBuilder::new(&shell, false);
126
127 let (program, args) = shell_builder.build(
128 Some("echo".into()),
129 &[
130 "${hello}".to_string(),
131 "$world".to_string(),
132 "nothing".to_string(),
133 "--$something".to_string(),
134 "$".to_string(),
135 "${test".to_string(),
136 ],
137 );
138
139 assert_eq!(program, "nu");
140 assert_eq!(
141 args,
142 vec![
143 "-i",
144 "-c",
145 "echo $env.hello $env.world nothing --($env.something) $ ${test"
146 ]
147 );
148 }
149
150 #[test]
151 fn redirect_stdin_to_dev_null_precedence() {
152 let shell = Shell::Program("nu".to_owned());
153 let shell_builder = ShellBuilder::new(&shell, false);
154
155 let (program, args) = shell_builder
156 .redirect_stdin_to_dev_null()
157 .build(Some("echo".into()), &["nothing".to_string()]);
158
159 assert_eq!(program, "nu");
160 assert_eq!(args, vec!["-i", "-c", "(echo nothing) </dev/null"]);
161 }
162
163 #[test]
164 fn redirect_stdin_to_dev_null_fish() {
165 let shell = Shell::Program("fish".to_owned());
166 let shell_builder = ShellBuilder::new(&shell, false);
167
168 let (program, args) = shell_builder
169 .redirect_stdin_to_dev_null()
170 .build(Some("echo".into()), &["test".to_string()]);
171
172 assert_eq!(program, "fish");
173 assert_eq!(args, vec!["-i", "-c", "begin; echo test; end </dev/null"]);
174 }
175}