use YAML parser for sidecar files

The syntax so far is (compatible with) YAML.

Cargo.lock

@@ -14,6 +14,7 @@ dependencies = [
  "tokio",
  "tokio-rustls",
  "url",
+ "yaml-rust",
 ]
 
 [[package]]
@@ -141,6 +142,12 @@ version = "0.2.85"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7ccac4b00700875e6a07c6cde370d44d32fa01c5a65cdd2fca6858c479d28bb3"
 
+[[package]]
+name = "linked-hash-map"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7fb9b38af92608140b86b693604b9ffcc5824240a484d1ecd4795bacb2fe88f3"
+
 [[package]]
 name = "log"
 version = "0.4.14"
@@ -539,3 +546,12 @@ name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
+
+[[package]]
+name = "yaml-rust"
+version = "0.4.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "56c1936c4cc7a1c9ab21a1ebb602eb942ba868cbd44a99cb7cdc5892335e1c85"
+dependencies = [
+ "linked-hash-map",
+]

Cargo.toml

@@ -22,6 +22,7 @@ once_cell = "1.5"
 percent-encoding = "2.1"
 rustls = "0.19.0"
 url = "2.2"
+yaml-rust = "0.4"
 
 [profile.release]
 lto = true

src/main.rs

@@ -30,11 +30,12 @@ fn main() -> Result {
             .init();
     }
     Runtime::new()?.block_on(async {
-        let mimetypes = Arc::new(Mutex::new(FileOptions::new(PresetMeta::Parameters(
+        let default = PresetMeta::Parameters(
             ARGS.language
                 .as_ref()
                 .map_or(String::new(), |lang| format!(";lang={}", lang)),
-        ))));
+        );
+        let mimetypes = Arc::new(Mutex::new(FileOptions::new(default)));
         let listener = TcpListener::bind(&ARGS.addrs[..]).await?;
         log::info!("Listening on {:?}...", ARGS.addrs);
         loop {

src/metadata.rs

@@ -1,7 +1,7 @@
 use std::collections::BTreeMap;
-use std::io::{BufRead, BufReader};
 use std::path::PathBuf;
 use std::time::SystemTime;
+use yaml_rust::YamlLoader;
 
 static SIDECAR_FILENAME: &str = ".meta";
 
@@ -108,24 +108,39 @@ impl FileOptions {
         db.push(SIDECAR_FILENAME);
         let db = db.as_path();
 
-        if let Ok(file) = std::fs::File::open(db) {
+        if let Ok(contents) = std::fs::read_to_string(db) {
-            let r = BufReader::new(file);
+            let docs = match YamlLoader::load_from_str(&contents) {
-            r.lines()
+                Ok(docs) => docs,
-                // discard any I/O errors
+                Err(e) => {
-                .filter_map(|line| line.ok())
+                    log::error!("Invalid YAML document in {:?}: {}", db, e);
-                // filter out comment lines
+                    return;
-                .filter(|line| !line.trim_start().starts_with('#'))
+                }
-                .for_each(|line| {
+            };
-                    // split line at colon
+            if let Some(files) = docs.get(0).and_then(|hash| hash.as_hash()) {
-                    let parts = line.splitn(2, ':').collect::<Vec<_>>();
+                for (rel_path, header) in files {
-                    // only continue if line fits the format
+                    // from YAML to Rust types
-                    if parts.len() == 2 {
+                    let rel_path = if let Some(rel_path) = rel_path.as_str() {
+                        rel_path
+                    } else {
+                        log::error!(
+                            "Expected string filename, but got {:?} in {:?}",
+                            rel_path,
+                            db
+                        );
+                        continue;
+                    };
+                    let header = if let Some(header) = header.as_str() {
+                        header
+                    } else {
+                        log::error!("Expected string contents, but got {:?} in {:?}", header, db);
+                        continue;
+                    };
+
                     // generate workspace-unique path
                     let mut path = db_dir.clone();
-                        path.push(parts[0].trim());
+                    path.push(rel_path);
-                        // parse the line
-                        let header = parts[1].trim();
 
+                    // parse the preset
                     let preset = if header.is_empty() || header.starts_with(';') {
                         PresetMeta::Parameters(header.to_string())
                     } else if matches!(header.chars().next(), Some('1'..='6')) {
@@ -143,7 +158,8 @@ impl FileOptions {
                             // other whitespace to it (e.g. tabs)
                             log::warn!("Full Header line for {:?} has an invalid character, treating {:?} as a space.", path, separator);
                         }
-                            let status = header.chars()
+                        let status = header
+                            .chars()
                             .take(2)
                             .collect::<String>()
                             .parse::<u8>()
@@ -157,11 +173,17 @@ impl FileOptions {
                         // must be a MIME type, but without status code
                         PresetMeta::FullMime(header.to_string())
                     };
+
                     self.file_meta.insert(path, preset);
                 }
-                });
+            } else {
+                log::error!("no YAML document {:?}", db);
+                return;
+            };
             self.databases_read
                 .insert(db_dir.clone(), SystemTime::now());
+        } else {
+            log::error!("could not read configuration file {:?}", db);
         }
     }