migrate helix-syntax crate into helix-core and helix-term

helix-syntax mostly existed for the sake of the build task which
checks and compiles the submodules. Since we won't be relying on
that process anymore, it doesn't end up making much sense to have
a very thin crate just for some functions that we could port to
helix-core.

The remaining build-related code is moved to helix-term which will
be able to provide grammar builds through the --build-grammars CLI
flag.

2 files changed, 36 insertions, 5 deletions

diff --git a/helix-core/Cargo.toml b/helix-core/Cargo.toml
index 6682c37f..5582d38b 100644
--- a/helix-core/Cargo.toml
+++ b/helix-core/Cargo.toml
@@ -13,8 +13,6 @@ include = ["src/**/*", "README.md"]
 [features]
 
 [dependencies]
-helix-syntax = { version = "0.6", path = "../helix-syntax" }
-
 ropey = "1.3"
 smallvec = "1.8"
 smartstring = "1.0.0"
@@ -40,5 +38,8 @@ encoding_rs = "0.8"
 
 chrono = { version = "0.4", default-features = false, features = ["alloc", "std"] }
 
+libloading = "0.7"
+anyhow = "1"
+
 [dev-dependencies]
 quickcheck = { version = "1", default-features = false }
diff --git a/helix-core/src/syntax.rs b/helix-core/src/syntax.rs
index 53d20da3..0f7d224d 100644
--- a/helix-core/src/syntax.rs
+++ b/helix-core/src/syntax.rs
@@ -7,7 +7,9 @@ use crate::{
     Rope, RopeSlice, Tendril,
 };
 
-pub use helix_syntax::get_language;
+use anyhow::{Context, Result};
+use libloading::{Library, Symbol};
+use tree_sitter::Language;
 
 use arc_swap::{ArcSwap, Guard};
 use slotmap::{DefaultKey as LayerId, HopSlotMap};
@@ -25,6 +27,34 @@ use std::{
 use once_cell::sync::{Lazy, OnceCell};
 use serde::{Deserialize, Serialize};
 
+#[cfg(unix)]
+pub const DYLIB_EXTENSION: &str = "so";
+
+#[cfg(windows)]
+pub const DYLIB_EXTENSION: &str = "dll";
+
+fn replace_dashes_with_underscores(name: &str) -> String {
+    name.replace('-', "_")
+}
+
+pub fn get_language(runtime_path: &std::path::Path, name: &str) -> Result<Language> {
+    let name = name.to_ascii_lowercase();
+    let mut library_path = runtime_path.join("grammars").join(&name);
+    library_path.set_extension(DYLIB_EXTENSION);
+
+    let library = unsafe { Library::new(&library_path) }
+        .with_context(|| format!("Error opening dynamic library {:?}", &library_path))?;
+    let language_fn_name = format!("tree_sitter_{}", replace_dashes_with_underscores(&name));
+    let language = unsafe {
+        let language_fn: Symbol<unsafe extern "C" fn() -> Language> = library
+            .get(language_fn_name.as_bytes())
+            .with_context(|| format!("Failed to load symbol {}", language_fn_name))?;
+        language_fn()
+    };
+    std::mem::forget(library);
+    Ok(language)
+}
+
 fn deserialize_regex<'de, D>(deserializer: D) -> Result<Option<Regex>, D::Error>
 where
     D: serde::Deserializer<'de>,
@@ -426,7 +456,7 @@ impl LanguageConfiguration {
                 &injections_query,
                 &locals_query,
             )
-            .unwrap(); // TODO: avoid panic
+            .unwrap_or_else(|query_error| panic!("Could not parse queries for language {:?}. Are your grammars out of sync? Try running 'hx --fetch-grammars' and 'hx --build-grammars'. This query could not be parsed: {:?}", self.language_id, query_error));
 
             config.configure(scopes);
             Some(Arc::new(config))
@@ -2023,7 +2053,7 @@ mod test {
         );
 
         let loader = Loader::new(Configuration { language: vec![] });
-        let language = get_language(&crate::RUNTIME_DIR, "Rust").unwrap();
+        let language = get_language("Rust").unwrap();
 
         let query = Query::new(language, query_str).unwrap();
         let textobject = TextObjectQuery { query };