From fe9e2aefd4adac63821d0c007effcc8087e32ad6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= <l.s.r@web.de>
Date: Wed, 14 Jun 2017 20:24:25 +0200
Subject: pretty: recalculate duplicate short hashes

b9c6232138 (--format=pretty: avoid calculating expensive expansions
twice) optimized adding short hashes multiple times by using the
fact that the output strbuf was only ever simply appended to and
copying the added string from the previous run.  That prerequisite
is no longer given; we now have modfiers like %< and %+ that can
cause the cache to lose track of the correct offsets.  Remove it.

Reported-by: Michael Giuffrida <michaelpg@chromium.org>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/pretty.c b/pretty.c
index 0c31495..37b37d0 100644
--- a/pretty.c
+++ b/pretty.c
@@ -782,29 +782,9 @@ struct format_commit_context {
 	size_t body_off;
 
 	/* The following ones are relative to the result struct strbuf. */
-	struct chunk abbrev_commit_hash;
-	struct chunk abbrev_tree_hash;
-	struct chunk abbrev_parent_hashes;
 	size_t wrap_start;
 };
 
-static int add_again(struct strbuf *sb, struct chunk *chunk)
-{
-	if (chunk->len) {
-		strbuf_adddup(sb, chunk->off, chunk->len);
-		return 1;
-	}
-
-	/*
-	 * We haven't seen this chunk before.  Our caller is surely
-	 * going to add it the hard way now.  Remember the most likely
-	 * start of the to-be-added chunk: the current end of the
-	 * struct strbuf.
-	 */
-	chunk->off = sb->len;
-	return 0;
-}
-
 static void parse_commit_header(struct format_commit_context *context)
 {
 	const char *msg = context->message;
@@ -1136,24 +1116,16 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 		return 1;
 	case 'h':		/* abbreviated commit hash */
 		strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_COMMIT));
-		if (add_again(sb, &c->abbrev_commit_hash)) {
-			strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_RESET));
-			return 1;
-		}
 		strbuf_add_unique_abbrev(sb, commit->object.oid.hash,
 					 c->pretty_ctx->abbrev);
 		strbuf_addstr(sb, diff_get_color(c->auto_color, DIFF_RESET));
-		c->abbrev_commit_hash.len = sb->len - c->abbrev_commit_hash.off;
 		return 1;
 	case 'T':		/* tree hash */
 		strbuf_addstr(sb, oid_to_hex(&commit->tree->object.oid));
 		return 1;
 	case 't':		/* abbreviated tree hash */
-		if (add_again(sb, &c->abbrev_tree_hash))
-			return 1;
 		strbuf_add_unique_abbrev(sb, commit->tree->object.oid.hash,
 					 c->pretty_ctx->abbrev);
-		c->abbrev_tree_hash.len = sb->len - c->abbrev_tree_hash.off;
 		return 1;
 	case 'P':		/* parent hashes */
 		for (p = commit->parents; p; p = p->next) {
@@ -1163,16 +1135,12 @@ static size_t format_commit_one(struct strbuf *sb, /* in UTF-8 */
 		}
 		return 1;
 	case 'p':		/* abbreviated parent hashes */
-		if (add_again(sb, &c->abbrev_parent_hashes))
-			return 1;
 		for (p = commit->parents; p; p = p->next) {
 			if (p != commit->parents)
 				strbuf_addch(sb, ' ');
 			strbuf_add_unique_abbrev(sb, p->item->object.oid.hash,
 						 c->pretty_ctx->abbrev);
 		}
-		c->abbrev_parent_hashes.len = sb->len -
-		                              c->abbrev_parent_hashes.off;
 		return 1;
 	case 'm':		/* left/right/bottom */
 		strbuf_addstr(sb, get_revision_mark(NULL, commit));
diff --git a/strbuf.c b/strbuf.c
index b839be4..df2c113 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -204,13 +204,6 @@ void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2)
 	strbuf_setlen(sb, sb->len + sb2->len);
 }
 
-void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
-{
-	strbuf_grow(sb, len);
-	memcpy(sb->buf + sb->len, sb->buf + pos, len);
-	strbuf_setlen(sb, sb->len + len);
-}
-
 void strbuf_addchars(struct strbuf *sb, int c, size_t n)
 {
 	strbuf_grow(sb, n);
diff --git a/strbuf.h b/strbuf.h
index ba8d5f1..ca4eff8 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -266,12 +266,6 @@ static inline void strbuf_addstr(struct strbuf *sb, const char *s)
 extern void strbuf_addbuf(struct strbuf *sb, const struct strbuf *sb2);
 
 /**
- * Copy part of the buffer from a given position till a given length to the
- * end of the buffer.
- */
-extern void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len);
-
-/**
  * This function can be used to expand a format string containing
  * placeholders. To that end, it parses the string and calls the specified
  * function for every percent sign found.
-- 
cgit v0.10.2-6-g49f6