From 62786f9a509a06ac031c066837d7a2285469677b Mon Sep 17 00:00:00 2001
From: Bryce Kwon <bryce@brycekwon.com>
Date: Sat, 8 Aug 2026 12:49:54 -1000
Subject: Emit generated runs in batches, not a write each

---
 source/ui-blame.c | 64 +++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 53 insertions(+), 11 deletions(-)

(limited to 'source/ui-blame.c')

diff --git a/source/ui-blame.c b/source/ui-blame.c
index 418e3ae..d6779c0 100644
--- a/source/ui-blame.c
+++ b/source/ui-blame.c
@@ -16,6 +16,38 @@
 #include "blame.h"
 
 
+/* Blame coalesces neighbouring lines from one commit, but a commit that
+ * touched several separate parts of the file still comes back once per part.
+ * Each of those repeats a full commit parse, so the rendered detail is kept
+ * and looked up by object id. */
+static struct string_list suspect_details = STRING_LIST_INIT_DUP;
+
+static void free_suspect_details(void)
+{
+	struct string_list_item *item;
+
+	for_each_string_list_item(item, &suspect_details)
+		free(item->util);
+	string_list_clear(&suspect_details, 0);
+}
+
+/* Write out a run of one repeated character. A single blame entry can cover
+ * the whole file, so the run is handed on in batches rather than built whole. */
+static void emit_chars(char ch, unsigned long count)
+{
+	struct strbuf run = STRBUF_INIT;
+
+	while (count) {
+		unsigned long n = count < HTML_BATCH ? count : HTML_BATCH;
+
+		strbuf_addchars(&run, ch, n);
+		html_raw(run.buf, run.len);
+		strbuf_reset(&run);
+		count -= n;
+	}
+	strbuf_release(&run);
+}
+
 static char *emit_suspect_detail(struct blame_origin *suspect)
 {
 	struct commitinfo *info;
@@ -47,7 +79,6 @@ static void emit_blame_entry_hash(struct blame_entry *ent)
 {
 	struct blame_origin *suspect = ent->suspect;
 	struct object_id *oid = &suspect->commit->object.oid;
-	unsigned long line = 0;
 
 	char *detail = emit_suspect_detail(suspect);
 	html("<span class='oid'>");
@@ -65,28 +96,36 @@ static void emit_blame_entry_hash(struct blame_entry *ent)
 				suspect->path);
 	}
 
-	while (line++ < ent->num_lines)
-		html("\n");
+	// Batched rather than one write per line of the entry.
+	emit_chars('\n', ent->num_lines);
 }
 
 static void emit_blame_entry_linenumber(struct blame_entry *ent)
 {
 	const char *numberfmt = "<a id='n%1$d' href='#n%1$d'>%1$d</a>\n";
-
-	unsigned long lineno = ent->lno;
-	while (lineno < ent->lno + ent->num_lines)
-		htmlf(numberfmt, ++lineno);
+	struct strbuf numbers = STRBUF_INIT;
+	int lineno = ent->lno;
+
+	// Batched rather than a formatted write per line of the entry.
+	while (lineno < ent->lno + ent->num_lines) {
+		strbuf_addf(&numbers, numberfmt, ++lineno);
+		if (numbers.len >= HTML_BATCH) {
+			html_raw(numbers.buf, numbers.len);
+			strbuf_reset(&numbers);
+		}
+	}
+	html_raw(numbers.buf, numbers.len);
+	strbuf_release(&numbers);
 }
 
 static void emit_blame_entry_line_background(struct blame_scoreboard *sb,
 					     struct blame_entry *ent)
 {
-	unsigned long line;
+	int line;
 	size_t len, maxlen = 2;
 	const char* pos, *endpos;
 
 	for (line = ent->lno; line < ent->lno + ent->num_lines; line++) {
-		html("\n");
 		pos = blame_nth_line(sb, line);
 		endpos = blame_nth_line(sb, line + 1);
 		len = 0;
@@ -99,8 +138,11 @@ static void emit_blame_entry_line_background(struct blame_scoreboard *sb,
 			maxlen = len;
 	}
 
-	for (len = 0; len < maxlen - 1; len++)
-		html(" ");
+	// The widest line decides the padding, so the entry has to be measured
+	// before any of it is written. The newlines do not depend on that
+	// measurement, so both runs go out batched once it is known.
+	emit_chars('\n', ent->num_lines);
+	emit_chars(' ', maxlen - 1);
 }
 
 struct walk_tree_context {
-- 
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