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Improved three-way blob merging code

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This fleshes out the code that generates a three-way merge of a set of
blobs.

It still actually does the three-way merge using an external executable
(ie just calling "merge"), but the interfaces have been cleaned up a lot
and are now fully based on the 'mmfile_t' interface, so if libxdiff were
to ever grow a compatible three-way-merge, it could probably be directly
plugged in.

It also uses the previous XDL_EMIT_COMMON functionality extension to
libxdiff to generate a made-up base file for the merge for the case where
no base file previously existed. This should be equivalent to what we
currently do in git-merge-one-file.sh:

	diff -u -La/$orig -Lb/$orig $orig $src2 | git-apply --no-add

except it should be much simpler and can be done using the direct libxdiff
interfaces.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Linus Torvalds
2006-06-28 22:06:36 -07:00
committed by Junio C Hamano
parent 83788070a3
commit 0c7993839b
3 changed files with 240 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

73
merge-tree.c
View File

@ -1,5 +1,6 @@
#include "cache.h"
#include "tree-walk.h"
#include "xdiff-interface.h"
#include "blob.h"
static const char merge_tree_usage[] = "git-merge-tree <base-tree> <branch1> <branch2>";
@ -52,6 +53,77 @@ static const char *explanation(struct merge_list *entry)
return "removed in remote";
}
extern void *merge_file(struct blob *, struct blob *, struct blob *, unsigned long *);
static void *result(struct merge_list *entry, unsigned long *size)
{
char type[20];
struct blob *base, *our, *their;
if (!entry->stage)
return read_sha1_file(entry->blob->object.sha1, type, size);
base = NULL;
if (entry->stage == 1) {
base = entry->blob;
entry = entry->link;
}
our = NULL;
if (entry && entry->stage == 2) {
our = entry->blob;
entry = entry->link;
}
their = NULL;
if (entry)
their = entry->blob;
return merge_file(base, our, their, size);
}
static void *origin(struct merge_list *entry, unsigned long *size)
{
char type[20];
while (entry) {
if (entry->stage == 2)
return read_sha1_file(entry->blob->object.sha1, type, size);
entry = entry->link;
}
return NULL;
}
static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf)
{
int i;
for (i = 0; i < nbuf; i++)
printf("%.*s", (int) mb[i].size, mb[i].ptr);
return 0;
}
static void show_diff(struct merge_list *entry)
{
unsigned long size;
mmfile_t src, dst;
xpparam_t xpp;
xdemitconf_t xecfg;
xdemitcb_t ecb;
xpp.flags = XDF_NEED_MINIMAL;
xecfg.ctxlen = 3;
xecfg.flags = 0;
ecb.outf = show_outf;
ecb.priv = NULL;
src.ptr = origin(entry, &size);
if (!src.ptr)
size = 0;
src.size = size;
dst.ptr = result(entry, &size);
if (!dst.ptr)
size = 0;
dst.size = size;
xdl_diff(&src, &dst, &xpp, &xecfg, &ecb);
free(src.ptr);
free(dst.ptr);
}
static void show_result_list(struct merge_list *entry)
{
printf("%s\n", explanation(entry));
@ -70,6 +142,7 @@ static void show_result(void)
walk = merge_result;
while (walk) {
show_result_list(walk);
show_diff(walk);
walk = walk->next;
}
}