implement read builtin

2 files changed, 43 insertions, 6 deletions

diff --git a/src/pipeline/builtins/command.rs b/src/pipeline/builtins/command.rs
index 8119a55..2e6b4af 100644
--- a/src/pipeline/builtins/command.rs
+++ b/src/pipeline/builtins/command.rs
@@ -1,5 +1,7 @@
 use crate::pipeline::prelude::*;
 
+use async_std::io::prelude::BufReadExt as _;
+
 pub struct Command {
     exe: crate::parse::Exe,
     f: super::Builtin,
@@ -196,16 +198,17 @@ impl Io {
         }
     }
 
-    pub async fn read_stdin(&self, buf: &mut [u8]) -> anyhow::Result<usize> {
+    pub async fn read_line_stdin(&self) -> anyhow::Result<String> {
+        let mut buf = String::new();
         if let Some(fh) = self.stdin() {
             if let File::In(fh) = &mut *fh.lock_arc().await {
-                Ok(fh.read(buf).await?)
-            } else {
-                Ok(0)
+                fh.read_line(&mut buf).await?;
             }
-        } else {
-            Ok(0)
         }
+        if buf.ends_with('\n') {
+            buf.truncate(buf.len() - 1);
+        }
+        Ok(buf)
     }
 
     pub async fn write_stdout(&self, buf: &[u8]) -> anyhow::Result<()> {
diff --git a/src/pipeline/builtins/mod.rs b/src/pipeline/builtins/mod.rs
index 9670c0f..4e9cf2a 100644
--- a/src/pipeline/builtins/mod.rs
+++ b/src/pipeline/builtins/mod.rs
@@ -20,6 +20,7 @@ static BUILTINS: once_cell::sync::Lazy<
     builtins.insert("setenv", &setenv);
     builtins.insert("unsetenv", &unsetenv);
     builtins.insert("echo", &echo);
+    builtins.insert("read", &read);
     builtins.insert("and", &and);
     builtins.insert("or", &or);
     builtins.insert("command", &command);
@@ -217,6 +218,39 @@ fn echo(
     }))
 }
 
+#[allow(clippy::unnecessary_wraps)]
+fn read(
+    exe: crate::parse::Exe,
+    env: &Env,
+    cfg: command::Cfg,
+) -> anyhow::Result<command::Child> {
+    async fn async_read(
+        exe: crate::parse::Exe,
+        _env: &Env,
+        cfg: command::Cfg,
+    ) -> std::process::ExitStatus {
+        let var = if let Some(var) = exe.args().get(0).map(String::as_str) {
+            var
+        } else {
+            bail!(cfg, exe, "usage: read var");
+        };
+
+        let val = match cfg.io().read_line_stdin().await {
+            Ok(line) => line,
+            Err(e) => {
+                bail!(cfg, exe, e);
+            }
+        };
+
+        std::env::set_var(var, val);
+        async_std::process::ExitStatus::from_raw(0)
+    }
+
+    Ok(command::Child::new_fut(async move {
+        async_read(exe, env, cfg).await
+    }))
+}
+
 fn and(
     mut exe: crate::parse::Exe,
     env: &Env,