Fix panic when loading bad text in the GUI.

src/gui/filesystem.rs

@@ -48,14 +48,16 @@ use dirs;
 use log::warn;
 use std::fs;
 use std::io::BufRead;
-use syntect::easy::HighlightFile;
+use std::path::Path;
+use syntect::easy::{HighlightFile, HighlightLines};
 use syntect::highlighting::ThemeSet;
 use syntect::html::{
     IncludeBackground, append_highlighted_html_for_styled_line, start_highlighted_html_snippet,
 };
 use syntect::parsing::SyntaxSet;
+use syntect::util::LinesWithEndings;
 
-// TODO: Impleent a provider for QFileSystemModel::setIconProvider for icons.
+// TODO: Implement a provider for QFileSystemModel::setIconProvider for icons.
 pub struct FileSystemImpl {
     file_path: QString,
     root_index: QModelIndex,
@@ -76,42 +78,46 @@ impl qobject::FileSystem {
         if path.is_empty() {
             return QString::default();
         }
-        if !fs::metadata(path.to_string())
-            .expect(format!("Failed to get file metadata {path:?}").as_str())
-            .is_file()
-        {
+        let meta = fs::metadata(path.to_string())
+            .expect(format!("Failed to get file metadata {path:?}").as_str());
+        if !meta.is_file() {
             warn!(target:"FileSystem", "Attempted to open file {path:?} that is not a valid file");
             return QString::default();
         }
-        let ss = SyntaxSet::load_defaults_nonewlines();
-        let ts = ThemeSet::load_defaults();
-        let theme = &ts.themes["base16-ocean.dark"];
+        let path_str = path.to_string();
+        if let Ok(lines) = fs::read_to_string(path_str.as_str()) {
+            let ss = SyntaxSet::load_defaults_nonewlines();
+            let ts = ThemeSet::load_defaults();
+            let theme = &ts.themes["base16-ocean.dark"];
+            let lang = ss
+                .find_syntax_by_extension(
+                    Path::new(path_str.as_str())
+                        .extension()
+                        .map(|s| s.to_str())
+                        .unwrap_or_else(|| Some("md"))
+                        .expect("Failed to get file extension"),
+                )
+                .unwrap_or_else(|| ss.find_syntax_plain_text());
+            let mut highlighter = HighlightLines::new(lang, theme);
+            let (mut output, _bg) = start_highlighted_html_snippet(theme);
+            for line in LinesWithEndings::from(lines.as_str()) {
+                let regions = highlighter
+                    .highlight_line(line, &ss)
+                    .expect("Failed to highlight");
 
-        let mut highlighter =
-            HighlightFile::new(path.to_string(), &ss, theme).expect("Failed to create highlighter");
-        let (mut output, _bg) = start_highlighted_html_snippet(theme);
-        let mut line = String::new();
-        while highlighter
-            .reader
-            .read_line(&mut line)
-            .expect("Failed to read file.")
-            > 0
-        {
-            let regions = highlighter
-                .highlight_lines
-                .highlight_line(&line, &ss)
-                .expect("Failed to highlight");
+                append_highlighted_html_for_styled_line(
+                    &regions[..],
+                    IncludeBackground::Yes,
+                    &mut output,
+                )
+                .expect("Failed to insert highlighted html");
+            }
 
-            append_highlighted_html_for_styled_line(
-                &regions[..],
-                IncludeBackground::Yes,
-                &mut output,
-            )
-            .expect("Failed to insert highlighted html");
-            line.clear();
+            output.push_str("</pre>\n");
+            QString::from(output)
+        } else {
+            return QString::default();
         }
-        output.push_str("</pre>\n");
-        QString::from(output)
     }
 
     // There will never be more than one column.