Submodules

src/submodule.rs

@@ -0,0 +1,140 @@
+//! Implements a simplistic form of git submodules.
+//! 
+//! The config format is as follows:
+//! 
+//! A list of
+//! ```toml
+//! [[submodule]]
+//! name = ""
+//! url = ""
+//! commit = ""
+//! ```
+//! 
+//! For example,
+//! ```toml
+//! [[submodule]]
+//! name = "nixos"
+//! url = "https://github.com/Nilstrieb/nixos.git"
+//! commit = "c5b2fc10b9266b105d792d958b8f13479866a7bd"
+//! ```
+//! 
+//! This module will check them out into a directory called `submodules` in the current directory.
+//! Make sure to put this directory into `.gitignore`. 
+
+use std::{io, path, process};
+
+use color_eyre::{
+    eyre::{Context, OptionExt},
+    Result,
+};
+
+use crate::utils;
+
+pub struct Submodules {
+    configs: Vec<SyncConfig>,
+}
+
+pub struct SyncConfig {
+    name: String,
+    url: String,
+    commit: String,
+}
+
+impl Submodules {
+    pub fn parse(s: &str) -> Result<Submodules> {
+        let doc = s.parse::<toml::Table>().wrap_err("invalid toml")?;
+        let subs = doc
+            .get("submodule")
+            .ok_or_eyre("no top-level submodule tables")?;
+        let mods = subs.as_array().ok_or_eyre("submodule is not an array")?;
+
+        let mut configs = Vec::new();
+
+        for module in mods {
+            let map = module.as_table().ok_or_eyre("submodule is not a table")?;
+
+            let get_str = |name| -> Result<String> {
+                Ok(map
+                    .get(name)
+                    .ok_or_eyre(format!("{name} is missing"))?
+                    .as_str()
+                    .ok_or_eyre(format!("{name} is not a string"))?
+                    .into())
+            };
+
+            configs.push(SyncConfig {
+                name: get_str("name")?,
+                url: get_str("url")?,
+                commit: get_str("commit")?,
+            });
+        }
+
+        Ok(Self { configs })
+    }
+}
+
+pub fn sync(config: &Submodules) -> color_eyre::Result<()> {
+    info!("Syncing submodules...");
+
+    let submodules_path = path::Path::new("submodules");
+
+    match std::fs::create_dir(submodules_path) {
+        Ok(()) => info!("Created ./submodules"),
+        Err(e) if e.kind() == io::ErrorKind::AlreadyExists => {}
+        e => return e.wrap_err("failed to create submodules"),
+    }
+
+    for sync in &config.configs {
+        let name = &sync.name;
+        let url = sync.url.as_str();
+
+        let span = info_span!("Syncing submodule", ?name, ?url);
+        let _span = span.enter();
+
+        let sub_path = submodules_path.join(name);
+        if !sub_path.exists() {
+            info!(?name, ?url, "Cloning");
+            let mut cmd = process::Command::new("git");
+            cmd.args(&["clone", url, sub_path.to_str().unwrap()]);
+            utils::run_process(&mut cmd).wrap_err("running git clone")?;
+        } else {
+            debug!(?name, ?url, "Repo already exists");
+        }
+
+        let current_commit = utils::run_process(
+            process::Command::new("git")
+                .args(&["rev-parse", "HEAD"])
+                .current_dir(&sub_path),
+        )
+        .wrap_err("running git rev-parse HEAD")?;
+
+        debug!(?current_commit, "Current commit");
+
+        if current_commit.trim() != sync.commit {
+            info!("Need to change commit");
+            let commit_exists = utils::run_process(
+                process::Command::new("git")
+                    .args(&["cat-file", "-t", sync.commit.as_str()])
+                    .current_dir(&sub_path),
+            );
+            if !commit_exists.is_ok_and(|typ| typ == "commit\n".to_owned()) {
+                info!("Must fetch commit");
+                utils::run_process(process::Command::new("git").current_dir(&sub_path).args(&[
+                    "fetch",
+                    "origin",
+                    sync.commit.as_str(),
+                ]))
+                .wrap_err("git fetch")?;
+            }
+
+            utils::run_process(process::Command::new("git").current_dir(&sub_path).args(&[
+                "reset",
+                "--hard",
+                sync.commit.as_str(),
+            ]))
+            .wrap_err("git reset --hard")?;
+        }
+    }
+
+    Ok(())
+}