feat: implement FParkan architecture foundation

Add the modular fparkan workspace, domain crates, adapters, apps, xtask policy/CI, acceptance evidence, and licensed corpus gates for the macOS-focused roadmap foundation.

1 files changed, 456 insertions, 0 deletions

diff --git a/crates/fparkan-vfs/src/lib.rs b/crates/fparkan-vfs/src/lib.rs
new file mode 100644
index 0000000..dd71670
--- /dev/null
+++ b/crates/fparkan-vfs/src/lib.rs
@@ -0,0 +1,456 @@
+#![forbid(unsafe_code)]
+//! Virtual filesystem ports for resource loading.
+
+use fparkan_path::{join_under, NormalizedPath};
+use std::collections::BTreeMap;
+use std::fs;
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+
+/// VFS metadata.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct VfsMetadata {
+    /// Byte length.
+    pub len: u64,
+    /// Stable-enough source fingerprint for cache invalidation.
+    pub fingerprint: u64,
+}
+
+/// VFS entry.
+#[derive(Clone, Debug, Eq, PartialEq)]
+pub struct VfsEntry {
+    /// Path.
+    pub path: NormalizedPath,
+    /// Metadata.
+    pub metadata: VfsMetadata,
+}
+
+/// VFS error.
+#[derive(Debug)]
+pub enum VfsError {
+    /// Missing entry.
+    NotFound(String),
+    /// Ambiguous host path.
+    Ambiguous(String),
+    /// I/O error.
+    Io(std::io::Error),
+    /// Invalid path.
+    Path,
+}
+
+impl std::fmt::Display for VfsError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Self::NotFound(path) => write!(f, "not found: {path}"),
+            Self::Ambiguous(path) => write!(f, "ambiguous host path: {path}"),
+            Self::Io(err) => write!(f, "{err}"),
+            Self::Path => write!(f, "invalid path"),
+        }
+    }
+}
+
+impl std::error::Error for VfsError {}
+
+/// Resource VFS.
+pub trait Vfs: Send + Sync {
+    /// Reads metadata.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`VfsError`] when the path is invalid, missing, or cannot be
+    /// inspected by the backing store.
+    fn metadata(&self, path: &NormalizedPath) -> Result<VfsMetadata, VfsError>;
+    /// Reads bytes.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`VfsError`] when the path is invalid, missing, or cannot be
+    /// read by the backing store.
+    fn read(&self, path: &NormalizedPath) -> Result<Arc<[u8]>, VfsError>;
+    /// Lists entries below prefix.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`VfsError`] when the prefix is invalid, missing, or cannot be
+    /// traversed by the backing store.
+    fn list(&self, prefix: &NormalizedPath) -> Result<Vec<VfsEntry>, VfsError>;
+}
+
+/// Host directory VFS.
+#[derive(Clone, Debug)]
+pub struct DirectoryVfs {
+    root: PathBuf,
+}
+
+impl DirectoryVfs {
+    /// Creates a directory VFS.
+    #[must_use]
+    pub fn new(root: impl AsRef<Path>) -> Self {
+        Self {
+            root: root.as_ref().to_path_buf(),
+        }
+    }
+
+    fn host_path(&self, path: &NormalizedPath) -> Result<PathBuf, VfsError> {
+        let exact = join_under(&self.root, path).map_err(|_| VfsError::Path)?;
+        if exact.exists() {
+            return Ok(exact);
+        }
+        resolve_casefolded(&self.root, path.as_str())
+    }
+}
+
+impl Vfs for DirectoryVfs {
+    fn metadata(&self, path: &NormalizedPath) -> Result<VfsMetadata, VfsError> {
+        let meta = fs::metadata(self.host_path(path)?).map_err(VfsError::Io)?;
+        Ok(metadata_from_fs(&meta))
+    }
+
+    fn read(&self, path: &NormalizedPath) -> Result<Arc<[u8]>, VfsError> {
+        let bytes = fs::read(self.host_path(path)?).map_err(VfsError::Io)?;
+        Ok(Arc::from(bytes.into_boxed_slice()))
+    }
+
+    fn list(&self, prefix: &NormalizedPath) -> Result<Vec<VfsEntry>, VfsError> {
+        let base = self.host_path(prefix)?;
+        let mut entries = Vec::new();
+        if base.is_file() {
+            let metadata = fs::metadata(&base).map_err(VfsError::Io)?;
+            entries.push(VfsEntry {
+                path: prefix.clone(),
+                metadata: metadata_from_fs(&metadata),
+            });
+            return Ok(entries);
+        }
+        list_recursive(&self.root, &base, &mut entries)?;
+        entries.sort_by(|a, b| a.path.as_str().cmp(b.path.as_str()));
+        Ok(entries)
+    }
+}
+
+fn resolve_casefolded(root: &Path, normalized: &str) -> Result<PathBuf, VfsError> {
+    let mut current = root.to_path_buf();
+    for segment in normalized.split('/') {
+        let read_dir = fs::read_dir(&current).map_err(VfsError::Io)?;
+        let mut matches = Vec::new();
+        for entry in read_dir {
+            let entry = entry.map_err(VfsError::Io)?;
+            let name = entry.file_name();
+            let Some(name) = name.to_str() else {
+                continue;
+            };
+            if name.eq_ignore_ascii_case(segment) {
+                matches.push(entry.path());
+            }
+        }
+        current = select_casefolded_match(normalized, &current, segment, matches)?;
+    }
+    Ok(current)
+}
+
+fn select_casefolded_match(
+    normalized: &str,
+    current: &Path,
+    segment: &str,
+    mut matches: Vec<PathBuf>,
+) -> Result<PathBuf, VfsError> {
+    matches.sort();
+    match matches.len() {
+        0 => Err(VfsError::NotFound(normalized.to_string())),
+        1 => Ok(matches.remove(0)),
+        _ => Err(VfsError::Ambiguous(format!(
+            "{}/{}",
+            current.display(),
+            segment
+        ))),
+    }
+}
+
+fn list_recursive(root: &Path, dir: &Path, out: &mut Vec<VfsEntry>) -> Result<(), VfsError> {
+    let read_dir = fs::read_dir(dir).map_err(VfsError::Io)?;
+    let mut children = Vec::new();
+    for entry in read_dir {
+        let entry = entry.map_err(VfsError::Io)?;
+        children.push(entry.path());
+    }
+    children.sort();
+    for child in children {
+        let metadata = fs::metadata(&child).map_err(VfsError::Io)?;
+        if metadata.is_dir() {
+            list_recursive(root, &child, out)?;
+            continue;
+        }
+        if !metadata.is_file() {
+            continue;
+        }
+        let rel = child.strip_prefix(root).map_err(|_| VfsError::Path)?;
+        let rel_text = rel.to_str().ok_or(VfsError::Path)?;
+        let path = fparkan_path::normalize_relative(
+            rel_text.as_bytes(),
+            fparkan_path::PathPolicy::HostCompatible,
+        )
+        .map_err(|_| VfsError::Path)?;
+        out.push(VfsEntry {
+            path,
+            metadata: metadata_from_fs(&metadata),
+        });
+    }
+    Ok(())
+}
+
+fn metadata_from_fs(metadata: &fs::Metadata) -> VfsMetadata {
+    let mut fingerprint = 0xcbf2_9ce4_8422_2325;
+    hash_u64(&mut fingerprint, metadata.len());
+    if let Ok(modified) = metadata.modified() {
+        if let Ok(duration) = modified.duration_since(std::time::UNIX_EPOCH) {
+            hash_u64(&mut fingerprint, duration.as_secs());
+            hash_u64(&mut fingerprint, u64::from(duration.subsec_nanos()));
+        }
+    }
+    VfsMetadata {
+        len: metadata.len(),
+        fingerprint,
+    }
+}
+
+/// In-memory VFS.
+#[derive(Clone, Debug, Default)]
+pub struct MemoryVfs {
+    files: BTreeMap<String, Arc<[u8]>>,
+}
+
+impl MemoryVfs {
+    /// Inserts a file.
+    #[allow(clippy::needless_pass_by_value)]
+    pub fn insert(&mut self, path: NormalizedPath, bytes: Arc<[u8]>) {
+        self.files.insert(path.as_str().to_string(), bytes);
+    }
+}
+
+impl Vfs for MemoryVfs {
+    fn metadata(&self, path: &NormalizedPath) -> Result<VfsMetadata, VfsError> {
+        let bytes = self
+            .files
+            .get(path.as_str())
+            .ok_or_else(|| VfsError::NotFound(path.as_str().to_string()))?;
+        Ok(VfsMetadata {
+            len: bytes.len() as u64,
+            fingerprint: stable_hash(bytes),
+        })
+    }
+
+    fn read(&self, path: &NormalizedPath) -> Result<Arc<[u8]>, VfsError> {
+        self.files
+            .get(path.as_str())
+            .cloned()
+            .ok_or_else(|| VfsError::NotFound(path.as_str().to_string()))
+    }
+
+    fn list(&self, prefix: &NormalizedPath) -> Result<Vec<VfsEntry>, VfsError> {
+        let mut out = Vec::new();
+        for (path, bytes) in &self.files {
+            if path
+                .as_bytes()
+                .get(..prefix.as_str().len())
+                .is_some_and(|head| head.eq_ignore_ascii_case(prefix.as_str().as_bytes()))
+            {
+                let normalized = fparkan_path::normalize_relative(
+                    path.as_bytes(),
+                    fparkan_path::PathPolicy::StrictLegacy,
+                )
+                .map_err(|_| VfsError::Path)?;
+                out.push(VfsEntry {
+                    path: normalized,
+                    metadata: VfsMetadata {
+                        len: bytes.len() as u64,
+                        fingerprint: stable_hash(bytes),
+                    },
+                });
+            }
+        }
+        Ok(out)
+    }
+}
+
+fn stable_hash(bytes: &[u8]) -> u64 {
+    let mut state = 0xcbf2_9ce4_8422_2325;
+    for byte in bytes {
+        state ^= u64::from(*byte);
+        state = state.wrapping_mul(0x0000_0100_0000_01b3);
+    }
+    state
+}
+
+fn hash_u64(state: &mut u64, value: u64) {
+    for byte in value.to_le_bytes() {
+        *state ^= u64::from(byte);
+        *state = state.wrapping_mul(0x0000_0100_0000_01b3);
+    }
+}
+
+/// Layered VFS with deterministic first-layer precedence.
+#[derive(Clone, Default)]
+pub struct OverlayVfs {
+    layers: Vec<Arc<dyn Vfs>>,
+}
+
+impl std::fmt::Debug for OverlayVfs {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("OverlayVfs")
+            .field("layers", &self.layers.len())
+            .finish()
+    }
+}
+
+impl OverlayVfs {
+    /// Creates an empty overlay.
+    #[must_use]
+    pub fn new() -> Self {
+        Self::default()
+    }
+
+    /// Creates an overlay from ordered layers.
+    #[must_use]
+    pub fn from_layers(layers: Vec<Arc<dyn Vfs>>) -> Self {
+        Self { layers }
+    }
+
+    /// Appends a lower-priority layer.
+    pub fn push_layer(&mut self, layer: Arc<dyn Vfs>) {
+        self.layers.push(layer);
+    }
+}
+
+impl Vfs for OverlayVfs {
+    fn metadata(&self, path: &NormalizedPath) -> Result<VfsMetadata, VfsError> {
+        for layer in &self.layers {
+            match layer.metadata(path) {
+                Ok(metadata) => return Ok(metadata),
+                Err(VfsError::NotFound(_)) => {}
+                Err(err) => return Err(err),
+            }
+        }
+        Err(VfsError::NotFound(path.as_str().to_string()))
+    }
+
+    fn read(&self, path: &NormalizedPath) -> Result<Arc<[u8]>, VfsError> {
+        for layer in &self.layers {
+            match layer.read(path) {
+                Ok(bytes) => return Ok(bytes),
+                Err(VfsError::NotFound(_)) => {}
+                Err(err) => return Err(err),
+            }
+        }
+        Err(VfsError::NotFound(path.as_str().to_string()))
+    }
+
+    fn list(&self, prefix: &NormalizedPath) -> Result<Vec<VfsEntry>, VfsError> {
+        let mut by_key = BTreeMap::new();
+        for layer in &self.layers {
+            match layer.list(prefix) {
+                Ok(entries) => {
+                    for entry in entries {
+                        let key = entry.path.as_str().to_ascii_uppercase();
+                        by_key.entry(key).or_insert(entry);
+                    }
+                }
+                Err(VfsError::NotFound(_)) => {}
+                Err(err) => return Err(err),
+            }
+        }
+        let mut entries: Vec<_> = by_key.into_values().collect();
+        entries.sort_by(|a, b| a.path.as_str().cmp(b.path.as_str()));
+        Ok(entries)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use fparkan_path::{normalize_relative, PathPolicy};
+
+    #[test]
+    fn directory_vfs_resolves_ascii_casefolded_segments() {
+        let root = unique_test_dir("casefold");
+        let dir = root.join("data").join("MAPS").join("Tut_1");
+        std::fs::create_dir_all(&dir).expect("mkdir");
+        std::fs::write(dir.join("Land.msh"), b"mesh").expect("write");
+
+        let vfs = DirectoryVfs::new(&root);
+        let path = normalize_relative(b"DATA/maps/tut_1/land.MSH", PathPolicy::StrictLegacy)
+            .expect("path");
+        assert_eq!(vfs.read(&path).expect("read").as_ref(), b"mesh");
+
+        std::fs::remove_dir_all(root).expect("cleanup");
+    }
+
+    #[test]
+    fn directory_vfs_lists_files_below_prefix() {
+        let root = unique_test_dir("list");
+        std::fs::create_dir_all(root.join("DATA").join("MAPS")).expect("mkdir");
+        std::fs::write(root.join("DATA").join("MAPS").join("Land.map"), b"map").expect("write");
+        std::fs::write(root.join("BuildDat.lst"), b"build").expect("write");
+
+        let vfs = DirectoryVfs::new(&root);
+        let prefix = normalize_relative(b"data", PathPolicy::StrictLegacy).expect("prefix");
+        let entries = vfs.list(&prefix).expect("list");
+        assert_eq!(entries.len(), 1);
+        assert!(entries[0]
+            .path
+            .as_str()
+            .eq_ignore_ascii_case("DATA/MAPS/Land.map"));
+
+        std::fs::remove_dir_all(root).expect("cleanup");
+    }
+
+    #[test]
+    fn casefold_selector_reports_ambiguous_segments() {
+        let err = select_casefolded_match(
+            "data/file.bin",
+            Path::new("/game"),
+            "data",
+            vec![PathBuf::from("/game/Data"), PathBuf::from("/game/DATA")],
+        )
+        .expect_err("ambiguous path");
+
+        assert!(matches!(err, VfsError::Ambiguous(_)));
+    }
+
+    #[test]
+    fn memory_vfs_uses_exact_lookup() {
+        let path = normalize_relative(b"Data/File.bin", PathPolicy::StrictLegacy).expect("path");
+        let mut vfs = MemoryVfs::default();
+        vfs.insert(path.clone(), Arc::from(b"payload".as_slice()));
+
+        assert_eq!(vfs.metadata(&path).expect("metadata").len, 7);
+        assert_eq!(vfs.read(&path).expect("read").as_ref(), b"payload");
+
+        let other_case =
+            normalize_relative(b"data/file.bin", PathPolicy::StrictLegacy).expect("path");
+        assert!(matches!(vfs.read(&other_case), Err(VfsError::NotFound(_))));
+    }
+
+    #[test]
+    fn overlay_vfs_uses_first_matching_layer() {
+        let path = normalize_relative(b"DATA/File.bin", PathPolicy::StrictLegacy).expect("path");
+        let prefix = normalize_relative(b"DATA", PathPolicy::StrictLegacy).expect("prefix");
+        let mut high = MemoryVfs::default();
+        let mut low = MemoryVfs::default();
+        high.insert(path.clone(), Arc::from(b"high".as_slice()));
+        low.insert(path.clone(), Arc::from(b"low".as_slice()));
+
+        let overlay = OverlayVfs::from_layers(vec![Arc::new(high), Arc::new(low)]);
+
+        assert_eq!(overlay.read(&path).expect("read").as_ref(), b"high");
+        let entries = overlay.list(&prefix).expect("list");
+        assert_eq!(entries.len(), 1);
+        assert_eq!(entries[0].metadata.len, 4);
+    }
+
+    fn unique_test_dir(name: &str) -> PathBuf {
+        let mut path = std::env::temp_dir();
+        path.push(format!("fparkan-vfs-{name}-{}", std::process::id()));
+        let _ = std::fs::remove_dir_all(&path);
+        path
+    }
+}