feat(ariadne): add pipeline skeleton

src/ariadne/BUILD

@@ -3,7 +3,10 @@ load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
 rust_library(
     name = "ariadne_lib",
     crate_name = "ariadne",
-    srcs = ["lib.rs"],
+    srcs = [
+        "lib.rs",
+        "pipeline.rs",
+    ],
 )
 
 rust_binary(

src/ariadne/lib.rs

@@ -1,7 +1,12 @@
-use std::collections::HashSet;
 use std::fs;
-use std::io::{self, Write};
-use std::path::{Path, PathBuf};
+use std::io;
+use std::path::PathBuf;
+
+use crate::pipeline::Stage;
+
+pub mod pipeline;
+
+const OUTPUT_GRAPH_DIR: &str = "graph";
 
 pub type Result<T> = io::Result<T>;
 
@@ -9,99 +14,46 @@ pub type Result<T> = io::Result<T>;
 pub struct Config {
     pub output_dir: PathBuf,
     pub force: bool,
-}
-
-impl Config {
-    pub fn new(output_dir: PathBuf, force: bool) -> Self {
-        Self { output_dir, force }
-    }
-}
-
-#[derive(Debug, Clone, Copy, Eq, Hash, PartialEq)]
-pub enum Stage {
-    Parse,
-}
-
-impl Stage {
-    pub const ALL: &'static [Stage] = &[Stage::Parse];
-
-    pub fn name(self) -> &'static str {
-        match self {
-            Stage::Parse => "parse",
-        }
-    }
-
-    pub fn prerequisites(self) -> &'static [Stage] {
-        match self {
-            Stage::Parse => &[],
-        }
-    }
+    pub target_stage: pipeline::Stage,
 }
 
 pub fn run(config: &Config) -> Result<()> {
-    let stdout = io::stdout();
-    let mut handle = stdout.lock();
-    run_with_writer(config, &mut handle)
-}
-
-pub fn run_with_writer(config: &Config, writer: &mut dyn Write) -> Result<()> {
-    for stage in plan_stages(Stage::ALL) {
-        run_stage(stage, config, writer)?;
+    for stage in config.target_stage.with_prerequisites() {
+        run_stage(config, stage)?;
     }
+
     Ok(())
 }
 
-fn plan_stages(stages: &[Stage]) -> Vec<Stage> {
-    fn visit(stage: Stage, seen: &mut HashSet<Stage>, planned: &mut Vec<Stage>) {
-        if !seen.insert(stage) {
-            return;
+fn get_output_dir(config: &Config, stage: Stage) -> Result<PathBuf> {
+    let output_dir = config.output_dir.join(OUTPUT_GRAPH_DIR).join(stage.name());
+
+    if output_dir.exists() && !output_dir.is_dir() {
+        return Err(io::Error::new(
+            io::ErrorKind::NotADirectory,
+            format!("output path is not a directory: {path}", path = output_dir.display()),
+        ));
+    }
+
+    if output_dir.is_dir() && fs::read_dir(&output_dir)?.next().transpose()?.is_some() {
+        if !config.force {
+            return Err(io::Error::new(
+                io::ErrorKind::AlreadyExists,
+                format!(
+                    "output directory already exists and is not empty: {path}",
+                    path = output_dir.display()
+                ),
+            ));
         }
-        for prerequisite in stage.prerequisites() {
-            visit(*prerequisite, seen, planned);
-        }
-        planned.push(stage);
+
+        fs::remove_dir_all(&output_dir)?;
     }
 
-    let mut seen = HashSet::new();
-    let mut planned = Vec::new();
-    for stage in stages {
-        visit(*stage, &mut seen, &mut planned);
-    }
-    planned
+    fs::create_dir_all(&output_dir)?;
+    Ok(output_dir)
 }
 
-fn run_stage(stage: Stage, config: &Config, writer: &mut dyn Write) -> Result<()> {
-    let stage_dir = stage_dir(&config.output_dir, stage);
-
-    if stage_dir.exists() {
-        if config.force {
-            fs::remove_dir_all(&stage_dir)?;
-        } else {
-            writeln!(
-                writer,
-                "SKIP {}: output exists at {}",
-                stage.name(),
-                stage_dir.display()
-            )?;
-            return Ok(());
-        }
-    }
-
-    writeln!(writer, "RUN {}", stage.name())?;
-    match stage {
-        Stage::Parse => run_parse(&stage_dir, writer)?,
-    }
-    Ok(())
-}
-
-fn stage_dir(output_dir: &Path, stage: Stage) -> PathBuf {
-    output_dir.join("graph").join(stage.name())
-}
-
-fn run_parse(stage_dir: &Path, writer: &mut dyn Write) -> Result<()> {
-    fs::create_dir_all(stage_dir)?;
-    let summary_path = stage_dir.join("summary.txt");
-    fs::write(&summary_path, "parse stage placeholder\n")?;
-    writeln!(writer, "WRITE {}", summary_path.display())?;
-    Ok(())
+fn run_stage(config: &Config, stage: Stage) -> Result<()> {
+    let output_dir = get_output_dir(config, stage)?;
+    pipeline::run_stage(stage, &output_dir)
 }

src/ariadne/main.rs

@@ -1,27 +1,51 @@
 use std::path::PathBuf;
-use std::process::ExitCode;
 
 use clap::Parser;
 
 #[derive(Debug, Parser)]
-#[command(name = "ariadne", about = "Analyze Clew output for a Ren'Py game.")]
-struct Cli {
+struct Args {
     #[arg(long, default_value = "output")]
     output_dir: PathBuf,
 
     #[arg(long)]
     force: bool,
+
+    #[arg(default_value = "all", value_parser = parse_stage)]
+    target_stage: ariadne::pipeline::Stage,
 }
 
-fn main() -> ExitCode {
-    let cli = Cli::parse();
-    let config = ariadne::Config::new(cli.output_dir, cli.force);
-
-    match ariadne::run(&config) {
-        Ok(()) => ExitCode::SUCCESS,
-        Err(error) => {
-            eprintln!("ERROR: {error}");
-            ExitCode::FAILURE
+impl From<Args> for ariadne::Config {
+    fn from(args: Args) -> Self {
+        ariadne::Config {
+            output_dir: resolve_workspace_path(args.output_dir),
+            force: args.force,
+            target_stage: args.target_stage,
         }
     }
 }
+
+fn parse_stage(value: &str) -> Result<ariadne::pipeline::Stage, String> {
+    ariadne::pipeline::Stage::ALL
+        .iter()
+        .copied()
+        .find(|stage| stage.name() == value)
+        .ok_or_else(|| format!("unknown stage: {value}"))
+}
+
+// TODO: Move this into a shared Rust utility crate.
+fn resolve_workspace_path(path: PathBuf) -> PathBuf {
+    if path.is_absolute() {
+        return path;
+    }
+
+    if let Some(workspace) = std::env::var_os("BUILD_WORKSPACE_DIRECTORY") {
+        return PathBuf::from(workspace).join(path);
+    }
+
+    path
+}
+
+fn main() -> ariadne::Result<()> {
+    let config: ariadne::Config = Args::parse().into();
+    ariadne::run(&config)
+}

src/ariadne/pipeline.rs

@@ -0,0 +1,101 @@
+use std::collections::BTreeSet;
+use std::path::Path;
+
+use crate::Result;
+
+#[derive(Debug, Default, Clone, Copy, Eq, Hash, PartialEq, Ord, PartialOrd)]
+pub enum Stage {
+    #[default]
+    All,
+
+    Parse,
+    AddImplicitEdges,
+    AddInitEdges,
+    AddJumpEdges,
+}
+
+impl Stage {
+    pub const ALL: &'static [Stage] = &[
+        Stage::All,
+        Stage::Parse,
+        Stage::AddImplicitEdges,
+        Stage::AddInitEdges,
+        Stage::AddJumpEdges,
+    ];
+
+    pub fn name(self) -> &'static str {
+        match self {
+            Stage::All => "all",
+            Stage::Parse => "parse",
+            Stage::AddImplicitEdges => "add-implicit-edges",
+            Stage::AddInitEdges => "add-init-edges",
+            Stage::AddJumpEdges => "add-jump-edges",
+        }
+    }
+
+    pub fn prerequisites(self) -> &'static [Stage] {
+        match self {
+            Stage::All => &[
+                Stage::AddImplicitEdges,
+                Stage::AddInitEdges,
+                Stage::AddJumpEdges,
+            ],
+            Stage::Parse => &[],
+            Stage::AddImplicitEdges => &[Stage::Parse],
+            Stage::AddInitEdges => &[Stage::Parse],
+            Stage::AddJumpEdges => &[Stage::Parse],
+        }
+    }
+
+    pub fn with_prerequisites(self) -> Vec<Stage> {
+        self.with_prerequisites_impl(BTreeSet::new())
+    }
+
+    fn with_prerequisites_impl(self, seen: BTreeSet<Stage>) -> Vec<Stage> {
+        if seen.contains(&self) {
+            return Vec::new();
+        }
+
+        let mut seen = seen;
+        seen.insert(self);
+
+        let mut stages = Vec::new();
+        for prerequisite in self.prerequisites() {
+            let prerequisite_stages = prerequisite.with_prerequisites_impl(seen.clone());
+            seen.extend(prerequisite_stages.iter().copied());
+            stages.extend(prerequisite_stages);
+        }
+
+        if self != Stage::All {
+            stages.push(self);
+        }
+
+        stages
+    }
+}
+
+pub fn run_stage(stage: Stage, output_dir: &Path) -> Result<()> {
+    match stage {
+        Stage::All => Ok(()),
+        Stage::Parse => run_parse(output_dir),
+        Stage::AddImplicitEdges => run_add_implicit_edges(output_dir),
+        Stage::AddInitEdges => run_add_init_edges(output_dir),
+        Stage::AddJumpEdges => run_add_jump_edges(output_dir),
+    }
+}
+
+fn run_parse(_output_dir: &Path) -> Result<()> {
+    Ok(())
+}
+
+fn run_add_implicit_edges(_output_dir: &Path) -> Result<()> {
+    Ok(())
+}
+
+fn run_add_init_edges(_output_dir: &Path) -> Result<()> {
+    Ok(())
+}
+
+fn run_add_jump_edges(_output_dir: &Path) -> Result<()> {
+    Ok(())
+}