Add support for installing josh-proxy

Author: Kobzol

src/bin/josh_sync.rs

@@ -1,6 +1,8 @@
 use anyhow::Context;
 use clap::Parser;
 use josh_sync::JoshConfig;
+use josh_sync::josh::{JoshProxy, try_install_josh};
+use std::path::{Path, PathBuf};
 
 const DEFAULT_CONFIG_PATH: &str = "josh-sync.toml";
 
@@ -14,6 +16,12 @@ struct Args {
 enum Command {
     /// Initialize a config file for this repository.
     Init,
+    /// Pull changes from the main `rustc` repository.
+    /// This creates new commits that should be then merged into this subtree repository.
+    Pull {
+        #[clap(long, default_value(DEFAULT_CONFIG_PATH))]
+        config: PathBuf,
+    },
 }
 
 fn main() -> anyhow::Result<()> {
@@ -27,8 +35,40 @@ fn main() -> anyhow::Result<()> {
             };
             let config = toml::to_string_pretty(&config).context("cannot serialize config")?;
             std::fs::write(DEFAULT_CONFIG_PATH, config).context("cannot write config")?;
+            println!("Created config file at {DEFAULT_CONFIG_PATH}");
+        }
+        Command::Pull { config } => {
+            let config = load_config(&config)
+                .context("cannot load config. Run the `init` command to initialize it.")?;
+            let josh = get_josh_proxy()?;
         }
     }
 
     Ok(())
 }
+
+fn get_josh_proxy() -> anyhow::Result<JoshProxy> {
+    match JoshProxy::lookup() {
+        Some(proxy) => Ok(proxy),
+        None => {
+            println!("josh-proxy not found. Do you want to install it? [y/n]");
+            let mut line = String::new();
+            std::io::stdin().read_line(&mut line)?;
+            if line.trim().to_lowercase() == "y" {
+                match try_install_josh() {
+                    Some(proxy) => Ok(proxy),
+                    None => Err(anyhow::anyhow!("Could not install josh-proxy")),
+                }
+            } else {
+                Err(anyhow::anyhow!("josh-proxy could not be found"))
+            }
+        }
+    }
+}
+
+fn load_config(path: &Path) -> anyhow::Result<JoshConfig> {
+    let data = std::fs::read_to_string(path)
+        .with_context(|| format!("cannot load config file from {}", path.display()))?;
+    let config: JoshConfig = toml::from_str(&data).context("cannot load config as TOML")?;
+    Ok(config)
+}

src/josh.rs

@@ -12,7 +12,7 @@ impl JoshProxy {
     }
 }
 
-fn install_josh() -> Option<JoshProxy> {
+pub fn try_install_josh() -> Option<JoshProxy> {
     check_output(&[
         "cargo",
         "install",
@@ -21,6 +21,7 @@ fn install_josh() -> Option<JoshProxy> {
         "https://github.com/josh-project/josh",
         "--tag",
         "r24.10.04",
+        "josh-proxy",
     ]);
     JoshProxy::lookup()
 }