added hl-max-size to specify maximum file size for highlighting

This should help users to specify the max size for the documents since
highlighting takes too much resources when file size increases.
This setting is language specific. Thus, can be configured in
languages.toml

Author: xEgoist

book/src/languages.md

@@ -62,6 +62,7 @@ These configuration keys are available:
 | `grammar`             | The tree-sitter grammar to use (defaults to the value of `name`) |
 | `formatter`           | The formatter for the language, it will take precedence over the lsp when defined. The formatter must be able to take the original file as input from stdin and write the formatted file to stdout |
 | `max-line-length`     | Maximum line length. Used for the `:reflow` command           |
+| `hl-max-size`         | Maximum file size in bytes for syntax highlighting            |
 
 ### File-type detection and the `file-types` key
 

helix-core/src/syntax.rs

@@ -122,7 +122,8 @@ pub struct LanguageConfiguration {
     #[serde(default, skip_serializing, deserialize_with = "deserialize_auto_pairs")]
     pub auto_pairs: Option<AutoPairs>,
 
-    pub rulers: Option<Vec<u16>>, // if set, override editor's rulers
+    pub rulers: Option<Vec<u16>>,   // if set, override editor's rulers
+    pub hl_max_size: Option<usize>, // maximum file size in bytes for highlighting
 }
 
 #[derive(Debug, PartialEq, Eq, Hash)]

helix-view/src/document.rs

@@ -681,6 +681,13 @@ impl Document {
         loader: Option<Arc<helix_core::syntax::Loader>>,
     ) {
         if let (Some(language_config), Some(loader)) = (language_config, loader) {
+            if let Some(max_size) = language_config.hl_max_size {
+                if self.text.len_bytes() > max_size {
+                    self.syntax = None;
+                    self.language = Some(language_config);
+                    return;
+                }
+            }
             if let Some(highlight_config) = language_config.highlight_config(&loader.scopes()) {
                 let syntax = Syntax::new(&self.text, highlight_config, loader);
                 self.syntax = Some(syntax);