From e5f81ad604d09aac0e0bfdfb138928edf9c112d4 Mon Sep 17 00:00:00 2001
From: Ava Hahn <ava@sunnypup.io>
Date: Fri, 7 Apr 2023 12:21:22 -0700
Subject: [PATCH] shell pipe function prototype finished

---
 Readme.org       |  1 -
 src/stl/posix.rs | 88 ++++++++++++++++++++++++++++++++++++------------
 2 files changed, 67 insertions(+), 22 deletions(-)

diff --git a/Readme.org b/Readme.org
index d843061..345ec56 100644
--- a/Readme.org
+++ b/Readme.org
@@ -483,7 +483,6 @@ Note: this section only tracks the state of incomplete TODO items. Having everyt
 
 ** TODO Pre-alpha tasks
 - Shell module
-  - pipe control flow construct
   - ignore job control signals (if needed)
   - background processes
   - be able to list all background processes with j function
diff --git a/src/stl/posix.rs b/src/stl/posix.rs
index 470fd6f..d428846 100644
--- a/src/stl/posix.rs
+++ b/src/stl/posix.rs
@@ -172,48 +172,79 @@ Each one has their output redirected to the input of the next one.
 Example:
 (pipe
   (ls -la)
-  (grep '*.rs')
+  (grep '.rs')
   (tr -d '.rs'))";
 fn pipe_callback(ast: &Seg, syms: &mut SymTable, state: &mut ShellState) -> Result<Ctr, String> {
     if ast.is_empty() {
         return Err("need at least one argument".to_string())
     }
 
-    let mut input = Stdio::inherit();
+    let mut err: String = String::new();
+    // posix layer will never control pid 0
+    let mut lastpid = 0;
     if !ast.circuit(&mut |arg: &Ctr| -> bool {
         if let Ctr::Seg(command_form) = arg {
-            let args = VecDeque::from(args_from_ast(ast, syms));
+            let mut args = VecDeque::from(args_from_ast(command_form, syms));
             if args.is_empty() {
                 return false
             }
 
             if let Some(filepath) = run::find_on_path(args.pop_front().unwrap()) {
-                let tmp = Stdio::piped();
-                // TODO Youll just have to break open launch_command here
-                // youll need seperate calls for .stdin and .stdout anyways
-                // and also the move semantics are not working
-                launch_command(
-                    filepath,
-                    &Vec::from(args.make_contiguous()),
-                    input,
-                    Stdio::inherit(),
-                    tmp,
-                    false,
-                    state,
-                ).unwrap();
-                input = tmp;
-                true
+                let mut newchld = Command::new(filepath);
+                newchld.args(Vec::from(args.make_contiguous()))
+                    .stderr(Stdio::inherit())
+                    .stdout(Stdio::piped());
+
+                if let Some(pos) = state.children
+                    .iter()
+                    .position(|x| x.id() == lastpid)
+                {
+                    newchld.stdin(state.children.remove(pos).stdout.unwrap());
+                }
+
+                let chld_spwn = newchld.spawn();
+                if let Ok(child) = chld_spwn {
+                    let pid = child.id();
+                    lastpid = pid;
+                    state.children.push(child);
+                    true
+                } else {
+                    err = format!("failed to spawn: {}", chld_spwn.err().unwrap());
+                    false
+                }
+
             } else {
-                eprintln!("file not found");
+                err = "file not found".to_string();
                 false
             }
         } else {
+            err = format!("{} not a shell command", arg);
             false
         }
     }) {
-        Err("all arguments must be full shell commands".to_string())
+        Err(err)
     } else {
-        Ok(Ctr::None)
+        if lastpid > 0 {
+            if let Some(pos) = state.children
+                .iter()
+                .position(|x| x.id() == lastpid)
+            {
+                let chld = state.children.remove(pos);
+                let exit = chld.wait_with_output()
+                    .expect("failed to wait on last child");
+                state.last_exit_code = exit.status
+                    .code()
+                    .or_else(|| {Some(-1)})
+                    .unwrap();
+
+                println!("{}", String::from_utf8_lossy(&exit.stdout));
+                Ok(Ctr::Integer(state.last_exit_code.into()))
+            } else {
+                Err(format!("lost last child (pid {})", lastpid))
+            }
+        } else {
+            Err("impossible error state".to_string())
+        }
     }
 }
 
@@ -458,6 +489,7 @@ pub fn load_posix_shell(syms: &mut SymTable, shell_state: Rc<RefCell<ShellState>
     let q_ss = shell_state.clone();
     let lw_ss = shell_state.clone();
     let lts_ss = shell_state.clone();
+    let p_ss = shell_state.clone();
 
     syms.insert(
         String::from("l"),
@@ -543,6 +575,20 @@ pub fn load_posix_shell(syms: &mut SymTable, shell_state: Rc<RefCell<ShellState>
         },
     );
 
+    syms.insert(
+        String::from("pipe"),
+        Symbol {
+            name: String::from("pipe"),
+            args: Args::Infinite,
+            conditional_branches: true,
+            docs: String::from(PIPE_DOCSTRING),
+            value: ValueType::Internal(Rc::new(move |ast: &Seg, symtable: &mut SymTable| -> Result<Ctr, String> {
+                pipe_callback(ast, symtable, &mut p_ss.clone().borrow_mut())
+            })),
+            ..Default::default()
+        },
+    );
+
     if let Err(e) = ctrlc::set_handler(move || println!("POSIX layer caught SIG-something")) {
         eprintln!("WARNING: couldn't set sig handler: {}", e);
     }