Allow opening another TUI (e.g. text editor) temporarily before returning to watchbind

README.md

@@ -164,22 +164,25 @@ All supported `OP` values:
 
 Operation | Description
 :-- | :--
-`exit` | Quit watchbind
-`reload` | Reload the watched command manually, resets interval timer
-`cursor [down\|up] <N>` | Move cursor \[down\|up\] N number of lines
-`cursor [first\|last]` | Move cursor to the \[first\|last\] line
-`select` | Select line that cursor is currently on (i.e. add line that cursor is currently on to selected lines)
-`unselect` | Unselect line that cursor is currently on
-`toggle-selection` | Toggle selection of line that cursor is currently on
-`select-all` | Select all lines
-`unselect-all` | Unselect all currently selected lines
-`exec -- <CMD>` | Execute `CMD` and block until termination
-`exec & -- <CMD>` | Execute `CMD` as background process, i.e. don't block until command terminates
-`set-env <ENV> -- <CMD>` | Blockingly execute `CMD`, and save its output to the environment variable `ENV`
-`unset-env <ENV> -- <CMD>` | Unsets environment variable `ENV`
-`help-[show\|hide\|toggle]` | \[Show\|Hide\|Toggle\] the help menu that shows all activated keybindings
-
-All shell commands `CMD` will be executed in a subshell (i.e. `sh -c "CMD"`) that has the environment variable `line` set to the line the cursor is one and `lines` set to all selected lines or, if none are selected, the line the cursor is currently on.
+`exit` | Quit watchbind.
+`reload` | Reload the watched command manually, resets interval timer.
+`cursor [down\|up] <N>` | Move cursor \[down\|up\] N number of lines.
+`cursor [first\|last]` | Move cursor to the \[first\|last\] line.
+`select` | Select line that cursor is currently on (i.e. add line that cursor is currently on to selected lines).
+`unselect` | Unselect line that cursor is currently on.
+`toggle-selection` | Toggle selection of line that cursor is currently on.
+`select-all` | Select all lines.
+`unselect-all` | Unselect all currently selected lines.
+`exec -- <CMD>` | Execute `CMD` and block until termination.
+`exec & -- <CMD>` | Execute `CMD` as background process, i.e. don't block until command terminates.
+`exec tui -- <TUI-CMD>` | Execute a `TUI-CMD` that spawns a TUI (e.g. text editor). Watchbind's own TUI is replaced with `TUI-CMD`'s TUI until `TUI-CMD` terminates.
+`set-env <ENV> -- <CMD>` | Blockingly execute `CMD`, and save its output to the environment variable `ENV`.
+`unset-env <ENV> -- <CMD>` | Unsets environment variable `ENV`.
+`help-[show\|hide\|toggle]` | \[Show\|Hide\|Toggle\] the help menu that shows all activated keybindings.
+
+All `CMD` and `TUI-CMD` shell commands will be executed in a subshell (i.e. `sh -c "CMD"`) that has some environment variables set.
+The environment variable `line` is set to the line the cursor is on.
+The environment variable `lines` set to all selected lines, or if none are selected, the line the cursor is currently on.
 All set environment variables `ENV` will be made available in all future spawned commands/processes, including the watched command, any executed subcommands, as well as commands executed in `set-env` operations.
 If multiple lines are selected, they will be separated by newlines in `lines`.
 

examples/ls.toml

@@ -1,4 +1,4 @@
-watched-command = "ls -la"
+watched-command = "ls"
 interval = 3.0
 bold = false
 cursor-fg = "black"
@@ -27,4 +27,5 @@ header-lines = 1
   "exec -- notify-send \"Executing echo\"",
   "exec -- echo \"Trying to overwrite watchbind's lines with stdout\"",
   "exec -- echo \"Trying to overwrite watchbind's lines with stderr\" >&2"
-]
+]
+"e" = [ "exec tui -- nvim \"$line\"" ]

src/command.rs

@@ -30,6 +30,8 @@ pub struct WithEnv {
 pub struct NoOutput;
 #[derive(Clone)]
 pub struct WithOutput;
+#[derive(Clone)]
+pub struct InheritedIO;
 
 #[derive(Clone)]
 pub struct NonInterruptible;
@@ -61,46 +63,43 @@ pub struct CommandBuilder<B = NonBlocking, E = WithoutEnv, O = NoOutput, I = Non
 // TODO: impl default trait so we don't have to duplicate this
 impl CommandBuilder {
     pub fn new(command: String) -> Self {
-        let sh = ["sh", "-c", &command];
-        let mut process = TokioCommand::new(sh[0]);
-        process.args(&sh[1..]);
-        process.stdout(Stdio::null());
-        process.stderr(Stdio::null());
-
         CommandBuilder {
             // TODO: i think we don't even need command anymore, just the tokiocommand
             command,
             blocking: NonBlocking,
             output: NoOutput,
             interruptible: NonInterruptible,
             env: WithoutEnv,
-            tokio_command: Default::default(),
+            tokio_command: TokioCommandBuilder::default(),
         }
     }
 }
 
-/// Since we can't save a tokio::process::Command permanently and just clone it
-/// on new executions (it doesn't implement Clone), we store most of what's
-/// necessary to contruct it.
+/// Since we can't save a tokio::process::Command permanently and clone it
+/// on new executions (it doesn't implement Clone), we store what's
+/// needed to construct it.
 #[derive(Default, Clone)]
 struct TokioCommandBuilder {
+    stdin: StdioClonable,
     stdout: StdioClonable,
     stderr: StdioClonable,
 }
 
 // TODO: this should be known at compile-time as well, not have a match statement
 #[derive(Default, Clone)]
 enum StdioClonable {
-    Piped,
     #[default]
     Null,
+    Piped,
+    Inherit,
 }
 
 impl From<&StdioClonable> for Stdio {
     fn from(value: &StdioClonable) -> Self {
         match value {
-            StdioClonable::Piped => Stdio::piped(),
             StdioClonable::Null => Stdio::null(),
+            StdioClonable::Piped => Stdio::piped(),
+            StdioClonable::Inherit => Stdio::inherit(),
         }
     }
 }
@@ -150,6 +149,21 @@ impl<B, E, O, I> CommandBuilder<B, E, O, I> {
         }
     }
 
+    pub fn inherited_io(mut self) -> CommandBuilder<B, E, InheritedIO, I> {
+        // Required so child process can inherit IO from parent for TUI to work.
+        self.tokio_command.stdin = StdioClonable::Inherit;
+        self.tokio_command.stdout = StdioClonable::Inherit;
+
+        CommandBuilder {
+            command: self.command,
+            blocking: self.blocking,
+            output: InheritedIO,
+            interruptible: self.interruptible,
+            env: self.env,
+            tokio_command: self.tokio_command,
+        }
+    }
+
     pub fn interruptible(
         self,
         interrupt_rx: Receiver<InterruptSignal>,
@@ -171,8 +185,8 @@ impl<B, O, I> CommandBuilder<B, WithoutEnv, O, I> {
         let sh = ["sh", "-c", &self.command];
 
         let mut command = TokioCommand::new(sh[0]);
-
         command.args(&sh[1..]);
+        command.stdin(&self.tokio_command.stdin);
         command.stdout(&self.tokio_command.stdout);
         command.stderr(&self.tokio_command.stderr);
 
@@ -248,6 +262,17 @@ impl CommandBuilder<Blocking, WithEnv, NoOutput, NonInterruptible> {
     }
 }
 
+impl CommandBuilder<Blocking, WithEnv, InheritedIO, NonInterruptible> {
+    pub async fn execute(&self) -> Result<()> {
+        let mut child = self.create_shell_command().await.spawn()?;
+
+        let exit_status = child.wait().await?;
+        assert_child_exited_successfully(exit_status, &mut child.stderr).await?;
+
+        Ok(())
+    }
+}
+
 impl CommandBuilder<Blocking, WithoutEnv, WithOutput, NonInterruptible> {
     pub async fn execute(&self) -> Result<String> {
         let mut child = self.create_shell_command().await.spawn()?;
@@ -354,8 +379,8 @@ impl<B, E, O> CommandBuilder<B, E, O, Interruptible> {
     }
 }
 
-/// Return error in case the exit status/code indicates failure, and include
-/// stderr in error message.
+/// Return an error in case the exit status/exit code indicates failure, and
+/// include stderr in error message.
 async fn assert_child_exited_successfully(
     exit_status: ExitStatus,
     stderr: &mut Option<tokio::process::ChildStderr>,

src/config/keybindings/operations/operation.rs

@@ -1,10 +1,12 @@
-use crate::command::{Blocking, CommandBuilder, NonBlocking, WithEnv, WithOutput};
+use crate::command::{
+    Blocking, CommandBuilder, InheritedIO, NonBlocking, NonInterruptible, WithEnv, WithOutput,
+};
 use crate::ui::{EnvVariable, EnvVariables, Event, RequestedAction, State};
 use anyhow::Result;
 use parse_display::{Display, FromStr};
 use std::str;
 use std::sync::Arc;
-use tokio::sync::mpsc::Sender;
+use tokio::sync::mpsc::{self, Sender};
 use tokio::sync::Mutex;
 
 // TODO: use some rust pattern (with types) instead of hardcoded Operation{,Parsed} variants
@@ -33,6 +35,9 @@ pub enum OperationParsed {
     #[display("exec & -- {0}")]
     ExecuteNonBlocking(String),
 
+    #[display("exec tui -- {0}")]
+    ExecuteTUI(String),
+
     #[display("set-env {0} -- {1}")]
     SetEnv(EnvVariable, String),
 
@@ -51,13 +56,14 @@ pub enum Operation {
     HelpToggle,
     MoveCursor(MoveCursor),
     SelectLine(SelectOperation),
+    // TODO: document why we have an Arc (probably because it's shared across threads, but why? is it even necessary to share across threads given async)
     ExecuteBlocking(Arc<CommandBuilder<Blocking, WithEnv>>),
     ExecuteNonBlocking(Arc<CommandBuilder<NonBlocking, WithEnv>>),
+    ExecuteTUI(Arc<CommandBuilder<Blocking, WithEnv, InheritedIO, NonInterruptible>>),
     SetEnv(
         EnvVariable,
         Arc<CommandBuilder<Blocking, WithEnv, WithOutput>>,
     ),
-
     UnsetEnv(EnvVariable),
     ReadIntoEnv(EnvVariable),
 }
@@ -115,7 +121,7 @@ impl Operation {
                 state.add_lines_to_env().await?;
 
                 // TODO: these clones are preventable by using Arc<> (I think Arc<Mutex> isn't required because executing them doesn't mutate them)
-                let blocking_cmd = blocking_cmd.clone();
+                let blocking_cmd = Arc::clone(blocking_cmd);
                 let event_tx = event_tx.clone();
                 tokio::spawn(async move {
                     let result = blocking_cmd.execute().await;
@@ -126,10 +132,29 @@ impl Operation {
 
                 return Ok(RequestedAction::ExecutingBlockingSubcommand);
             }
+            Self::ExecuteTUI(tui_cmd) => {
+                state.add_lines_to_env().await?;
+
+                // Create channels for waiting until TUI has actually been hidden.
+                let (tui_hidden_tx, mut tui_hidden_rx) = mpsc::channel(1);
+
+                let tui_cmd = Arc::clone(tui_cmd);
+                let event_tx = event_tx.clone();
+                tokio::spawn(async move {
+                    // Wait until TUI has actually been hidden.
+                    let _ = tui_hidden_rx.recv().await;
+
+                    let result = tui_cmd.execute().await;
+
+                    // Ignore whether the sender has closed channel.
+                    let _ = event_tx.send(Event::TUISubcommandCompleted(result)).await;
+                });
+
+                return Ok(RequestedAction::ExecutingTUISubcommand(tui_hidden_tx));
+            }
             Self::SetEnv(env_variable, blocking_cmd) => {
                 state.add_lines_to_env().await?;
 
-                // TODO: these clones are preventable by using Arc<> (I think Arc<Mutex> isn't required because executing them doesn't mutate them)
                 let blocking_cmd = blocking_cmd.clone();
                 let env_variable = env_variable.clone();
                 let event_tx = event_tx.clone();
@@ -172,6 +197,12 @@ impl Operation {
             OperationParsed::ExecuteNonBlocking(cmd) => Self::ExecuteNonBlocking(Arc::new(
                 CommandBuilder::new(cmd).with_env(env_variables.clone()),
             )),
+            OperationParsed::ExecuteTUI(cmd) => Self::ExecuteTUI(Arc::new(
+                CommandBuilder::new(cmd)
+                    .blocking()
+                    .inherited_io()
+                    .with_env(env_variables.clone()),
+            )),
             OperationParsed::SetEnv(env_var, cmd) => Self::SetEnv(
                 env_var,
                 Arc::new(