Use os_pipe

src/exercise.rs

@@ -2,11 +2,42 @@ use anyhow::{Context, Result};
 use crossterm::style::{style, StyledContent, Stylize};
 use std::{
     fmt::{self, Display, Formatter},
-    path::Path,
-    process::{Command, Output},
+    io::{Read, Write},
+    process::Command,
 };
 
-use crate::{info_file::Mode, terminal_link::TerminalFileLink, DEBUG_PROFILE};
+use crate::{in_official_repo, info_file::Mode, terminal_link::TerminalFileLink, DEBUG_PROFILE};
+
+// TODO
+pub const OUTPUT_CAPACITY: usize = 1 << 12;
+
+fn run_command(mut cmd: Command, cmd_description: &str, output: &mut Vec<u8>) -> Result<bool> {
+    let (mut reader, writer) = os_pipe::pipe().with_context(|| {
+        format!("Failed to create a pipe to run the command `{cmd_description}``")
+    })?;
+
+    let mut handle = cmd
+        .stdout(writer.try_clone().with_context(|| {
+            format!("Failed to clone the pipe writer for the command `{cmd_description}`")
+        })?)
+        .stderr(writer)
+        .spawn()
+        .with_context(|| format!("Failed to run the command `{cmd_description}`"))?;
+
+    // Prevent pipe deadlock.
+    drop(cmd);
+
+    reader
+        .read_to_end(output)
+        .with_context(|| format!("Failed to read the output of the command `{cmd_description}`"))?;
+
+    output.push(b'\n');
+
+    handle
+        .wait()
+        .with_context(|| format!("Failed to wait on the command `{cmd_description}` to exit"))
+        .map(|status| status.success())
+}
 
 pub struct Exercise {
     pub dir: Option<&'static str>,
@@ -22,13 +53,30 @@ pub struct Exercise {
 }
 
 impl Exercise {
-    fn cargo_cmd(&self, command: &str, args: &[&str]) -> Result<Output> {
+    fn run_bin(&self, output: &mut Vec<u8>) -> Result<bool> {
+        writeln!(output, "{}", "Output".bold().magenta().underlined())?;
+
+        let bin_path = format!("target/debug/{}", self.name);
+        run_command(Command::new(&bin_path), &bin_path, output)
+    }
+
+    fn cargo_cmd(
+        &self,
+        command: &str,
+        args: &[&str],
+        cmd_description: &str,
+        output: &mut Vec<u8>,
+        dev: bool,
+    ) -> Result<bool> {
         let mut cmd = Command::new("cargo");
         cmd.arg(command);
 
         // A hack to make `cargo run` work when developing Rustlings.
-        if DEBUG_PROFILE && Path::new("tests").exists() {
-            cmd.arg("--manifest-path").arg("dev/Cargo.toml");
+        if dev {
+            cmd.arg("--manifest-path")
+                .arg("dev/Cargo.toml")
+                .arg("--target-dir")
+                .arg("target");
         }
 
         cmd.arg("--color")
@@ -36,15 +84,43 @@ impl Exercise {
             .arg("-q")
             .arg("--bin")
             .arg(self.name)
-            .args(args)
-            .output()
-            .context("Failed to run Cargo")
+            .args(args);
+
+        run_command(cmd, cmd_description, output)
     }
 
-    pub fn run(&self) -> Result<Output> {
+    fn cargo_cmd_with_bin_output(
+        &self,
+        command: &str,
+        args: &[&str],
+        cmd_description: &str,
+        output: &mut Vec<u8>,
+        dev: bool,
+    ) -> Result<bool> {
+        // Discard the output of `cargo build` because it will be shown again by the Cargo command.
+        output.clear();
+
+        let cargo_cmd_success = self.cargo_cmd(command, args, cmd_description, output, dev)?;
+
+        let run_success = self.run_bin(output)?;
+
+        Ok(cargo_cmd_success && run_success)
+    }
+
+    pub fn run(&self, output: &mut Vec<u8>) -> Result<bool> {
+        output.clear();
+
+        // Developing the official Rustlings.
+        let dev = DEBUG_PROFILE && in_official_repo();
+
+        let build_success = self.cargo_cmd("build", &[], "cargo build …", output, dev)?;
+        if !build_success {
+            return Ok(false);
+        }
+
         match self.mode {
-            Mode::Run => self.cargo_cmd("run", &[]),
-            Mode::Test => self.cargo_cmd(
+            Mode::Run => self.run_bin(output),
+            Mode::Test => self.cargo_cmd_with_bin_output(
                 "test",
                 &[
                     "--",
@@ -54,10 +130,16 @@ impl Exercise {
                     "--format",
                     "pretty",
                 ],
+                "cargo test …",
+                output,
+                dev,
             ),
-            Mode::Clippy => self.cargo_cmd(
+            Mode::Clippy => self.cargo_cmd_with_bin_output(
                 "clippy",
-                &["--", "-D", "warnings", "-D", "clippy::float_cmp"],
+                &["--", "-D", "warnings"],
+                "cargo clippy …",
+                output,
+                dev,
             ),
         }
     }