lightcraft/xtask/src/main.rs

//! Workspace tooling: `cargo xtask <command>`.
//!
//! Pure Rust (std + serde_json). External tools (`cargo`, `curl`, `tar`) are
//! invoked through `std::process::Command`.

mod layers;
mod stats;

use std::path::{Path, PathBuf};
use std::process::{Command, ExitCode};

const USAGE: &str = "\
usage: cargo xtask <command>

commands:
  layers          enforce the crate dependency layering (plan/architecture.md §3)
  wasm            cargo check --target wasm32-unknown-unknown for the wasm-safe crates
  ci              fmt --check, clippy -D warnings, test, layers, wasm (stops at first failure)
  corpus [--download]
                  show where test corpora live; --download fetches PngSuite into corpus/pngsuite
  stats [--exact] count tests and lines per crate (--exact: ask the test harness via `-- --list`)
";

fn main() -> ExitCode {
    let args: Vec<String> = std::env::args().skip(1).collect();
    let rest: Vec<&str> = args.iter().skip(1).map(String::as_str).collect();
    let result = match args.first().map(String::as_str) {
        Some("layers") => cmd_layers(),
        Some("wasm") => cmd_wasm(),
        Some("ci") => cmd_ci(),
        Some("corpus") => cmd_corpus(rest.contains(&"--download")),
        Some("stats") => stats::run(&root(), rest.contains(&"--exact")),
        Some("-h" | "--help" | "help") | None => {
            print!("{USAGE}");
            Ok(())
        }
        Some(other) => Err(format!("unknown command `{other}`\n\n{USAGE}")),
    };
    match result {
        Ok(()) => ExitCode::SUCCESS,
        Err(e) => {
            eprintln!("error: {e}");
            ExitCode::FAILURE
        }
    }
}

/// Workspace root (parent of the xtask crate).
pub fn root() -> PathBuf {
    Path::new(env!("CARGO_MANIFEST_DIR")).parent().expect("xtask has a parent dir").to_path_buf()
}

pub fn cargo() -> Command {
    let mut c = Command::new(std::env::var("CARGO").unwrap_or_else(|_| "cargo".into()));
    c.current_dir(root());
    c
}

fn run(mut cmd: Command, what: &str) -> Result<(), String> {
    eprintln!("$ {what}");
    let status = cmd.status().map_err(|e| format!("{what}: failed to spawn: {e}"))?;
    if status.success() { Ok(()) } else { Err(format!("{what}: exited with {status}")) }
}

pub fn metadata() -> Result<serde_json::Value, String> {
    let out = cargo().args(["metadata", "--format-version", "1", "--no-deps"]).output().map_err(|e| format!("cargo metadata: {e}"))?;
    if !out.status.success() {
        return Err(format!("cargo metadata failed:\n{}", String::from_utf8_lossy(&out.stderr)));
    }
    serde_json::from_slice(&out.stdout).map_err(|e| format!("cargo metadata: bad JSON: {e}"))
}

fn cmd_layers() -> Result<(), String> {
    let crates = layers::from_metadata(&metadata()?)?;
    println!("Dependency layering (plan/architecture.md §3)\n");
    println!("{:<28} {:<14} workspace deps", "crate", "layer");
    for c in &crates {
        let ws: Vec<String> = c
            .deps
            .iter()
            .filter(|d| d.workspace)
            .map(|d| {
                let k = match d.kind {
                    layers::DepKind::Normal => "",
                    layers::DepKind::Dev => " (dev)",
                    layers::DepKind::Build => " (build)",
                };
                format!("{}{k}", layers::short_name(&d.name))
            })
            .collect();
        println!("{:<28} {:<14} {}", c.name, layers::describe(layers::classify(&c.name)), ws.join(", "));
    }
    let violations = layers::check(&crates);
    println!();
    if violations.is_empty() {
        println!("OK: {} crates, no layering violations.", crates.len());
        Ok(())
    } else {
        println!("{} violation(s):", violations.len());
        for v in &violations {
            println!("  - {v}");
        }
        Err(format!("{} layering violation(s)", violations.len()))
    }
}

/// Workspace packages that must build for wasm32: all L0–L5 crates plus
/// the egui shell.
fn wasm_set() -> Result<Vec<String>, String> {
    let crates = layers::from_metadata(&metadata()?)?;
    Ok(crates
        .into_iter()
        .filter(|c| match layers::classify(&c.name) {
            Some(layers::Class::Layer(l)) => l <= 5,
            Some(layers::Class::Standalone) => true,
            _ => false,
        })
        .map(|c| c.name)
        .collect())
}

fn cmd_wasm() -> Result<(), String> {
    let set = wasm_set()?;
    let mut results = Vec::new();
    for pkg in &set {
        let mut c = cargo();
        c.args(["check", "--target", "wasm32-unknown-unknown", "-p", pkg]);
        let ok = run(c, &format!("cargo check --target wasm32-unknown-unknown -p {pkg}")).is_ok();
        results.push((pkg.clone(), ok));
    }
    println!("\nwasm32-unknown-unknown check:");
    for (p, ok) in &results {
        println!("  {:<6} {p}", if *ok { "ok" } else { "FAIL" });
    }
    let failed = results.iter().filter(|r| !r.1).count();
    if failed == 0 { Ok(()) } else { Err(format!("{failed} crate(s) failed the wasm check")) }
}

fn cmd_ci() -> Result<(), String> {
    type Step = (&'static str, Box<dyn Fn() -> Result<(), String>>);
    let steps: Vec<Step> = vec![
        (
            "fmt",
            Box::new(|| {
                let mut c = cargo();
                c.args(["fmt", "--all", "--", "--check"]);
                run(c, "cargo fmt --all -- --check")
            }),
        ),
        (
            "clippy",
            Box::new(|| {
                let mut c = cargo();
                c.args(["clippy", "--workspace", "--all-targets", "--", "-D", "warnings"]);
                run(c, "cargo clippy --workspace --all-targets -- -D warnings")
            }),
        ),
        (
            "test",
            Box::new(|| {
                let mut c = cargo();
                c.args(["test", "--workspace"]);
                run(c, "cargo test --workspace")
            }),
        ),
        ("layers", Box::new(cmd_layers)),
        ("wasm", Box::new(cmd_wasm)),
    ];
    let mut done = Vec::new();
    for (name, f) in &steps {
        eprintln!("\n=== ci: {name} ===");
        if let Err(e) = f() {
            println!("\nCI summary:");
            for d in &done {
                println!("  ok    {d}");
            }
            println!("  FAIL  {name}: {e}");
            for (n, _) in steps.iter().skip(done.len() + 1) {
                println!("  skip  {n}");
            }
            return Err(format!("ci failed at `{name}`"));
        }
        done.push(*name);
    }
    println!("\nCI summary: all {} steps passed ({})", done.len(), done.join(", "));
    Ok(())
}

/// CC0 raw samples (raw.pixls.us). Small, representative set; extend freely (CC0 only).
const RAW_SAMPLES: &[(&str, &str)] = &[];

fn cmd_corpus(download: bool) -> Result<(), String> {
    let corpus = root().join("corpus");
    println!(
        "Test corpora live under {} (git-ignored, never committed).
Tests that use a corpus skip cleanly when it is absent.

  corpus/raw/        raw.pixls.us samples (CC0) — lightcraft-raw decodes every file.
  corpus/images/     CC0 / public-domain JPEG/PNG/TIFF/HEIC samples (optional)
",
        corpus.display()
    );
    if !download {
        return Ok(());
    }
    let dest = corpus.join("raw");
    std::fs::create_dir_all(&dest).map_err(|e| format!("create {}: {e}", dest.display()))?;
    for (name, url) in RAW_SAMPLES {
        let out = dest.join(name);
        if out.exists() {
            continue;
        }
        let mut curl = Command::new("curl");
        curl.args(["-fsSL", "-o"]).arg(&out).arg(url);
        run(curl, &format!("curl {url}"))?;
    }
    Ok(())
}