improve performance on diffing giant files (#96)

Author: Stephan Dilly

asyncgit/src/sync/diff.rs

@@ -71,7 +71,7 @@ pub struct FileDiff {
     /// list of hunks
     pub hunks: Vec<Hunk>,
     /// lines total summed up over hunks
-    pub lines: u16,
+    pub lines: usize,
 }
 
 pub(crate) fn get_diff_raw<'a>(
@@ -144,7 +144,7 @@ pub fn get_diff(
             header_hash: hash(header),
             lines: lines.clone(),
         });
-        res.lines += lines.len() as u16;
+        res.lines += lines.len();
     };
 
     let mut put = |hunk: Option<DiffHunk>, line: git2::DiffLine| {

src/components/diff.rs

@@ -172,7 +172,7 @@ impl DiffComponent {
 
             if Self::hunk_visible(hunk_min, hunk_max, min, max) {
                 for (i, line) in hunk.lines.iter().enumerate() {
-                    if line_cursor >= min {
+                    if line_cursor >= min && line_cursor <= max {
                         Self::add_line(
                             &mut res,
                             width,