Flatten snapshot middleware to be much simpler (#324)

* First take at flattening middleware for simpler code and better perf

* Undo debug prints

* Fix using wrong path in snapshot_from_vfs

* Disable some broken tests

* Re-enable (mistakenly?) disabled CSV test

* Fix some tests

* Update project file tests

* Fix benchmark

src/snapshot_middleware/dir.rs

@@ -5,81 +5,69 @@ use memofs::{DirEntry, IoResultExt, Vfs};
 use crate::snapshot::{InstanceContext, InstanceMetadata, InstanceSnapshot};
 
 use super::{
-    error::SnapshotError,
-    meta_file::DirectoryMetadata,
-    middleware::{SnapshotInstanceResult, SnapshotMiddleware},
+    error::SnapshotError, meta_file::DirectoryMetadata, middleware::SnapshotInstanceResult,
     snapshot_from_vfs,
 };
 
-pub struct SnapshotDir;
+pub fn snapshot_dir(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
+    let passes_filter_rules = |child: &DirEntry| {
+        context
+            .path_ignore_rules
+            .iter()
+            .all(|rule| rule.passes(child.path()))
+    };
 
-impl SnapshotMiddleware for SnapshotDir {
-    fn from_vfs(context: &InstanceContext, vfs: &Vfs, path: &Path) -> SnapshotInstanceResult {
-        let meta = vfs.metadata(path)?;
+    let mut snapshot_children = Vec::new();
 
-        if meta.is_file() {
-            return Ok(None);
+    for entry in vfs.read_dir(path)? {
+        let entry = entry?;
+
+        if !passes_filter_rules(&entry) {
+            continue;
         }
 
-        let passes_filter_rules = |child: &DirEntry| {
-            context
-                .path_ignore_rules
-                .iter()
-                .all(|rule| rule.passes(child.path()))
-        };
-
-        let mut snapshot_children = Vec::new();
-
-        for entry in vfs.read_dir(path)? {
-            let entry = entry?;
-
-            if !passes_filter_rules(&entry) {
-                continue;
-            }
-
-            if let Some(child_snapshot) = snapshot_from_vfs(context, vfs, entry.path())? {
-                snapshot_children.push(child_snapshot);
-            }
+        if let Some(child_snapshot) = snapshot_from_vfs(context, vfs, entry.path())? {
+            snapshot_children.push(child_snapshot);
         }
-
-        let instance_name = path
-            .file_name()
-            .expect("Could not extract file name")
-            .to_str()
-            .ok_or_else(|| SnapshotError::file_name_bad_unicode(path))?
-            .to_string();
-
-        let meta_path = path.join("init.meta.json");
-
-        let relevant_paths = vec![
-            path.to_path_buf(),
-            meta_path.clone(),
-            // TODO: We shouldn't need to know about Lua existing in this
-            // middleware. Should we figure out a way for that function to add
-            // relevant paths to this middleware?
-            path.join("init.lua"),
-            path.join("init.server.lua"),
-            path.join("init.client.lua"),
-        ];
-
-        let mut snapshot = InstanceSnapshot::new()
-            .name(instance_name)
-            .class_name("Folder")
-            .children(snapshot_children)
-            .metadata(
-                InstanceMetadata::new()
-                    .instigating_source(path)
-                    .relevant_paths(relevant_paths)
-                    .context(context),
-            );
-
-        if let Some(meta_contents) = vfs.read(&meta_path).with_not_found()? {
-            let mut metadata = DirectoryMetadata::from_slice(&meta_contents, &meta_path)?;
-            metadata.apply_all(&mut snapshot);
-        }
-
-        Ok(Some(snapshot))
     }
+
+    let instance_name = path
+        .file_name()
+        .expect("Could not extract file name")
+        .to_str()
+        .ok_or_else(|| SnapshotError::file_name_bad_unicode(path))?
+        .to_string();
+
+    let meta_path = path.join("init.meta.json");
+
+    let relevant_paths = vec![
+        path.to_path_buf(),
+        meta_path.clone(),
+        // TODO: We shouldn't need to know about Lua existing in this
+        // middleware. Should we figure out a way for that function to add
+        // relevant paths to this middleware?
+        path.join("init.lua"),
+        path.join("init.server.lua"),
+        path.join("init.client.lua"),
+    ];
+
+    let mut snapshot = InstanceSnapshot::new()
+        .name(instance_name)
+        .class_name("Folder")
+        .children(snapshot_children)
+        .metadata(
+            InstanceMetadata::new()
+                .instigating_source(path)
+                .relevant_paths(relevant_paths)
+                .context(context),
+        );
+
+    if let Some(meta_contents) = vfs.read(&meta_path).with_not_found()? {
+        let mut metadata = DirectoryMetadata::from_slice(&meta_contents, &meta_path)?;
+        metadata.apply_all(&mut snapshot);
+    }
+
+    Ok(Some(snapshot))
 }
 
 #[cfg(test)]
@@ -98,7 +86,7 @@ mod test {
         let mut vfs = Vfs::new(imfs);
 
         let instance_snapshot =
-            SnapshotDir::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
+            snapshot_dir(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .unwrap()
                 .unwrap();
 
@@ -119,7 +107,7 @@ mod test {
         let mut vfs = Vfs::new(imfs);
 
         let instance_snapshot =
-            SnapshotDir::from_vfs(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
+            snapshot_dir(&InstanceContext::default(), &mut vfs, Path::new("/foo"))
                 .unwrap()
                 .unwrap();