git.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Junio C Hamano <gitster@pobox.com>
To: git@vger.kernel.org
Subject: [PATCH 6/8] apply: fall back on three-way merge
Date: Wed,  9 May 2012 23:02:23 -0700	[thread overview]
Message-ID: <1336629745-22436-7-git-send-email-gitster@pobox.com> (raw)
In-Reply-To: <1336629745-22436-1-git-send-email-gitster@pobox.com>

Grab the preimage blob the patch claims to be based on out of the object
store, apply the patch, and then call three-way-merge function.

This step does not plug the actual three-way merge logic yet, but we are
getting there.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 builtin/apply.c | 46 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 44 insertions(+), 2 deletions(-)

diff --git a/builtin/apply.c b/builtin/apply.c
index b1dd23c..798a634 100644
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -3073,11 +3073,53 @@ static int load_preimage(struct image *image,
 	return 0;
 }
 
-static int try_threeway_fallback(struct image *image, struct patch *patch)
+static int three_way_merge(struct image *image,
+			   char *path,
+			   unsigned char *base,
+			   unsigned char *ours,
+			   unsigned char *theirs)
 {
 	return -1; /* for now */
 }
 
+static int try_threeway_fallback(struct image *image, struct patch *patch,
+				 struct stat *st, struct cache_entry *ce)
+{
+	unsigned char pre_sha1[20], post_sha1[20], our_sha1[20];
+	struct strbuf buf = STRBUF_INIT;
+	size_t len;
+	char *img;
+	struct image tmp_image;
+
+	/* No point falling back to 3-way merge in these cases */
+	if (patch->is_binary || patch->is_new || patch->is_delete ||
+	    S_ISGITLINK(patch->old_mode) || S_ISGITLINK(patch->new_mode))
+		return -1;
+
+	/* Preimage the patch was prepared for */
+	if (get_sha1(patch->old_sha1_prefix, pre_sha1) ||
+	    read_blob_object(&buf, pre_sha1, patch->old_mode))
+		return error("repository lacks necessary blobs to fall back on 3-way merge.");
+	img = strbuf_detach(&buf, &len);
+	prepare_image(&tmp_image, img, len, 1);
+	/* Apply the patch to get the post image */
+	if (apply_fragments(&tmp_image, patch) < 0) {
+		clear_image(&tmp_image);
+		return -1;
+	}
+	hash_sha1_file(tmp_image.buf, tmp_image.len, blob_type, post_sha1);
+	clear_image(&tmp_image);
+
+	/* pre_sha1[] is common, post_sha1[] is theirs */
+	load_preimage(&tmp_image, patch, st, ce);
+	hash_sha1_file(tmp_image.buf, tmp_image.len, blob_type, our_sha1);
+	clear_image(&tmp_image);
+
+	/* in-core three-way merge between post and our using pre as base */
+	return three_way_merge(image,
+			       patch->new_name, pre_sha1, our_sha1, post_sha1);
+}
+
 static int apply_data(struct patch *patch, struct stat *st, struct cache_entry *ce)
 {
 	struct image image;
@@ -3087,7 +3129,7 @@ static int apply_data(struct patch *patch, struct stat *st, struct cache_entry *
 
 	if (apply_fragments(&image, patch) < 0) {
 		/* Note: with --reject, the above call succeeds. */
-		if (!threeway || try_threeway_fallback(&image, patch) < 0)
+		if (!threeway || try_threeway_fallback(&image, patch, st, ce) < 0)
 			return -1;
 	}
 	patch->result = image.buf;
-- 
1.7.10.1.562.gfc79b1c

  parent reply	other threads:[~2012-05-10  6:03 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-10  6:02 [PATCH 0/8] "git apply --threeway" Junio C Hamano
2012-05-10  6:02 ` [PATCH 1/8] apply: reformat comment Junio C Hamano
2012-05-10  6:02 ` [PATCH 2/8] apply: accept --threeway command line option Junio C Hamano
2012-05-10 12:40   ` Nguyen Thai Ngoc Duy
2012-05-10 15:31     ` Junio C Hamano
2012-05-10  6:02 ` [PATCH 3/8] apply: split load_preimage() helper function out Junio C Hamano
2012-05-10  6:02 ` [PATCH 4/8] apply: clear_image() clears things a bit more Junio C Hamano
2012-05-10  6:02 ` [PATCH 5/8] apply: refactor read_file_or_gitlink() Junio C Hamano
2012-05-10  6:02 ` Junio C Hamano [this message]
2012-05-10  7:26   ` [PATCH 6/8] apply: fall back on three-way merge Matthieu Moy
2012-05-10 15:10     ` Junio C Hamano
2012-05-10 15:41       ` Matthieu Moy
2012-05-10 20:31   ` Jeff King
2012-05-10 21:06     ` Junio C Hamano
2012-05-10 22:24       ` Jeff King
2012-05-10  6:02 ` [PATCH 7/8] apply: plug the three-way merge logic in Junio C Hamano
2012-05-10  6:02 ` [PATCH 8/8] apply: register conflicted stages to the index Junio C Hamano
2012-05-10  7:31 ` [PATCH 0/8] "git apply --threeway" Matthieu Moy
2012-05-10 15:26   ` Junio C Hamano

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1336629745-22436-7-git-send-email-gitster@pobox.com \
    --to=gitster@pobox.com \
    --cc=git@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).