commit 7783f73c4beef7010e3332dee7f94dad9a54109f
from: Mark Jamsek <mark@jamsek.dev>
date: Mon Feb 20 04:31:13 2023 UTC

use chunk offset to efficiently detect conflict markers

Rather than skip lines, use the new diff APIs to directly seek to each
chunk with newly added lines for more efficient conflict marker detection.

ok stsp@

commit - 3db5a0afedc4111bd9721c0e5229cd217202ac84
commit + 7783f73c4beef7010e3332dee7f94dad9a54109f
blob - 2d75c470b84a9c0f07ca7ccd39595267ab24fd49
blob + 08328fe81ea2c2cf86331c9b155ab3b6134f9836
--- lib/worktree.c
+++ lib/worktree.c
@@ -1557,16 +1557,12 @@ get_modified_file_content_status(unsigned char *status
 	if (err)
 		goto done;
 
-	if (fseek(ondisk_file, 0L, SEEK_SET) == -1) {
-		err = got_ferror(ondisk_file, GOT_ERR_IO);
-		goto done;
-	}
-
 	r = diffreg_result->result;
 
 	for (n = 0; n < r->chunks.len; n += nchunks_parsed) {
 		struct diff_chunk *c;
 		struct diff_chunk_context cc = {};
+		off_t pos;
 		int clc, crc;
 
 		/*
@@ -1577,20 +1573,20 @@ get_modified_file_content_status(unsigned char *status
 		clc = diff_chunk_get_left_count(c);
 		crc = diff_chunk_get_right_count(c);
 
-		if (!crc && clc) {
+		if (!crc || crc == clc) {
 			nchunks_parsed = 1;
-			continue;  /* removed lines */
+			continue;  /* removed or unchanged lines */
 		}
 
-		diff_chunk_context_load_change(&cc, &nchunks_parsed, r, n, 0);
-
-		while (ln < cc.right.start) {
-			err = skip_one_line(ondisk_file);
-			if (err)
-				goto done;
-			++ln;
+		pos = diff_chunk_get_right_start_pos(c);
+		if (fseek(ondisk_file, pos, SEEK_SET) == -1) {
+			err = got_ferror(ondisk_file, GOT_ERR_IO);
+			goto done;
 		}
 
+		diff_chunk_context_load_change(&cc, &nchunks_parsed, r, n, 0);
+		ln = cc.right.start;
+
 		while (ln < cc.right.end) {
 			linelen = getline(&line, &linesize, ondisk_file);
 			if (linelen == -1) {