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.

4 files changed, 185 insertions, 0 deletions

diff --git a/helix-term/Cargo.toml b/helix-term/Cargo.toml
index 9f7821f6..93d50d7e 100644
--- a/helix-term/Cargo.toml
+++ b/helix-term/Cargo.toml
@@ -66,5 +66,9 @@ grep-searcher = "0.1.8"
 # Remove once retain_mut lands in stable rust
 retain_mut = "0.1.7"
 
+# compiling grammars
+cc = { version = "1" }
+threadpool = { version = "1.0" }
+
 [target.'cfg(not(windows))'.dependencies]  # https://github.com/vorner/signal-hook/issues/100
 signal-hook-tokio = { version = "0.3", features = ["futures-v0_3"] }
diff --git a/helix-term/build.rs b/helix-term/build.rs
index b5d62b28..7303041c 100644
--- a/helix-term/build.rs
+++ b/helix-term/build.rs
@@ -14,5 +14,10 @@ fn main() {
         None => env!("CARGO_PKG_VERSION").into(),
     };
 
+    println!(
+        "cargo:rustc-env=BUILD_TARGET={}",
+        std::env::var("TARGET").unwrap()
+    );
+
     println!("cargo:rustc-env=VERSION_AND_GIT_HASH={}", version);
 }
diff --git a/helix-term/src/grammars.rs b/helix-term/src/grammars.rs
new file mode 100644
index 00000000..6a4910a3
--- /dev/null
+++ b/helix-term/src/grammars.rs
@@ -0,0 +1,175 @@
+use anyhow::{anyhow, Context, Result};
+use std::fs;
+use std::time::SystemTime;
+use std::{
+    path::{Path, PathBuf},
+    process::Command,
+};
+
+use helix_core::syntax::DYLIB_EXTENSION;
+
+const BUILD_TARGET: &str = env!("BUILD_TARGET");
+
+pub fn collect_tree_sitter_dirs(ignore: &[String]) -> Result<Vec<String>> {
+    let mut dirs = Vec::new();
+    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../helix-syntax/languages");
+
+    for entry in fs::read_dir(path)? {
+        let entry = entry?;
+        let path = entry.path();
+
+        if !entry.file_type()?.is_dir() {
+            continue;
+        }
+
+        let dir = path.file_name().unwrap().to_str().unwrap().to_string();
+
+        // filter ignores
+        if ignore.contains(&dir) {
+            continue;
+        }
+        dirs.push(dir)
+    }
+
+    Ok(dirs)
+}
+
+fn build_library(src_path: &Path, language: &str) -> Result<()> {
+    let header_path = src_path;
+    // let grammar_path = src_path.join("grammar.json");
+    let parser_path = src_path.join("parser.c");
+    let mut scanner_path = src_path.join("scanner.c");
+
+    let scanner_path = if scanner_path.exists() {
+        Some(scanner_path)
+    } else {
+        scanner_path.set_extension("cc");
+        if scanner_path.exists() {
+            Some(scanner_path)
+        } else {
+            None
+        }
+    };
+    let parser_lib_path = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("../runtime/grammars");
+    let mut library_path = parser_lib_path.join(language);
+    library_path.set_extension(DYLIB_EXTENSION);
+
+    let recompile = needs_recompile(&library_path, &parser_path, &scanner_path)
+        .with_context(|| "Failed to compare source and binary timestamps")?;
+
+    if !recompile {
+        return Ok(());
+    }
+    let mut config = cc::Build::new();
+    config
+        .cpp(true)
+        .opt_level(2)
+        .cargo_metadata(false)
+        .host(BUILD_TARGET)
+        .target(BUILD_TARGET);
+    let compiler = config.get_compiler();
+    let mut command = Command::new(compiler.path());
+    command.current_dir(src_path);
+    for (key, value) in compiler.env() {
+        command.env(key, value);
+    }
+
+    if cfg!(windows) {
+        command
+            .args(&["/nologo", "/LD", "/I"])
+            .arg(header_path)
+            .arg("/Od")
+            .arg("/utf-8");
+        if let Some(scanner_path) = scanner_path.as_ref() {
+            command.arg(scanner_path);
+        }
+
+        command
+            .arg(parser_path)
+            .arg("/link")
+            .arg(format!("/out:{}", library_path.to_str().unwrap()));
+    } else {
+        command
+            .arg("-shared")
+            .arg("-fPIC")
+            .arg("-fno-exceptions")
+            .arg("-g")
+            .arg("-I")
+            .arg(header_path)
+            .arg("-o")
+            .arg(&library_path)
+            .arg("-O2");
+        if let Some(scanner_path) = scanner_path.as_ref() {
+            if scanner_path.extension() == Some("c".as_ref()) {
+                command.arg("-xc").arg("-std=c99").arg(scanner_path);
+            } else {
+                command.arg(scanner_path);
+            }
+        }
+        command.arg("-xc").arg(parser_path);
+        if cfg!(all(unix, not(target_os = "macos"))) {
+            command.arg("-Wl,-z,relro,-z,now");
+        }
+    }
+
+    let output = command
+        .output()
+        .with_context(|| "Failed to execute C compiler")?;
+    if !output.status.success() {
+        return Err(anyhow!(
+            "Parser compilation failed.\nStdout: {}\nStderr: {}",
+            String::from_utf8_lossy(&output.stdout),
+            String::from_utf8_lossy(&output.stderr)
+        ));
+    }
+
+    Ok(())
+}
+fn needs_recompile(
+    lib_path: &Path,
+    parser_c_path: &Path,
+    scanner_path: &Option<PathBuf>,
+) -> Result<bool> {
+    if !lib_path.exists() {
+        return Ok(true);
+    }
+    let lib_mtime = mtime(lib_path)?;
+    if mtime(parser_c_path)? > lib_mtime {
+        return Ok(true);
+    }
+    if let Some(scanner_path) = scanner_path {
+        if mtime(scanner_path)? > lib_mtime {
+            return Ok(true);
+        }
+    }
+    Ok(false)
+}
+
+fn mtime(path: &Path) -> Result<SystemTime> {
+    Ok(fs::metadata(path)?.modified()?)
+}
+
+pub fn build_dir(dir: &str, language: &str) {
+    println!("Build language {}", language);
+    if PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("../helix-syntax/languages")
+        .join(dir)
+        .read_dir()
+        .unwrap()
+        .next()
+        .is_none()
+    {
+        eprintln!(
+            "The directory {} is empty, you probably need to use './scripts/grammars sync'?",
+            dir
+        );
+        std::process::exit(1);
+    }
+
+    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .join("../helix-syntax/languages")
+        .join(dir)
+        .join("src");
+
+    build_library(&path, language).unwrap();
+}
diff --git a/helix-term/src/lib.rs b/helix-term/src/lib.rs
index fc8e934e..22747998 100644
--- a/helix-term/src/lib.rs
+++ b/helix-term/src/lib.rs
@@ -7,6 +7,7 @@ pub mod commands;
 pub mod compositor;
 pub mod config;
 pub mod health;
+pub mod grammars;
 pub mod job;
 pub mod keymap;
 pub mod ui;