die("Entry '%s' would be overwritten by merge. Cannot merge.", ce->name);
}
-static int merged_entry(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
+static int merged_entry_internal(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst, int allow_dirty)
{
merge->ce_flags |= htons(CE_UPDATE);
if (old) {
*/
if (same(old, merge)) {
*merge = *old;
- } else {
+ } else if (!allow_dirty) {
verify_uptodate(old);
}
}
return 1;
}
+static int merged_entry_allow_dirty(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
+{
+ return merged_entry_internal(merge, old, dst, 1);
+}
+
+static int merged_entry(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
+{
+ return merged_entry_internal(merge, old, dst, 0);
+}
+
+static int deleted_entry(struct cache_entry *ce, struct cache_entry *old, struct cache_entry **dst)
+{
+ if (old)
+ verify_uptodate(old);
+ ce->ce_mode = 0;
+ *dst++ = ce;
+ return 1;
+}
+
static int threeway_merge(struct cache_entry *stages[4], struct cache_entry **dst)
{
struct cache_entry *old = stages[0];
struct cache_entry *merge;
int count;
+ /* #5ALT */
+ if (!a && b && c && same(b, c)) {
+ if (old && !same(b, old))
+ return -1;
+ return merged_entry_allow_dirty(b, old, dst);
+ }
/*
* If we have an entry in the index cache ("old"), then we want
* to make sure that it matches any entries in stage 2 ("first
}
else if (oldtree && !newtree && same(current, oldtree)) {
/* 10 or 11 */
- verify_uptodate(current);
- return 0;
+ return deleted_entry(oldtree, current, dst);
}
else if (oldtree && newtree &&
same(current, oldtree) && !same(current, newtree)) {
/* 20 or 21 */
- verify_uptodate(current);
- return merged_entry(newtree, NULL, dst);
+ return merged_entry(newtree, current, dst);
}
else
/* all other failures */
return -1;
}
else if (newtree)
- return merged_entry(newtree, NULL, dst);
+ return merged_entry(newtree, current, dst);
else
- return 0;
+ return deleted_entry(oldtree, current, dst);
+}
+
+/*
+ * Two-way merge emulated with three-way merge.
+ *
+ * This treats "read-tree -m H M" by transforming it internally
+ * into "read-tree -m H I+H M", where I+H is a tree that would
+ * contain the contents of the current index file, overlayed on
+ * top of H. Unlike the traditional two-way merge, this leaves
+ * the stages in the resulting index file and lets the user resolve
+ * the merge conflicts using standard tools for three-way merge.
+ *
+ * This function is just to set-up such an arrangement, and the
+ * actual merge uses threeway_merge() function.
+ */
+static void setup_emu23(void)
+{
+ /* stage0 contains I, stage1 H, stage2 M.
+ * move stage2 to stage3, and create stage2 entries
+ * by scanning stage0 and stage1 entries.
+ */
+ int i, namelen, size;
+ struct cache_entry *ce, *stage2;
+
+ for (i = 0; i < active_nr; i++) {
+ ce = active_cache[i];
+ if (ce_stage(ce) != 2)
+ continue;
+ /* hoist them up to stage 3 */
+ namelen = ce_namelen(ce);
+ ce->ce_flags = create_ce_flags(namelen, 3);
+ }
+
+ for (i = 0; i < active_nr; i++) {
+ ce = active_cache[i];
+ if (ce_stage(ce) > 1)
+ continue;
+ namelen = ce_namelen(ce);
+ size = cache_entry_size(namelen);
+ stage2 = xmalloc(size);
+ memcpy(stage2, ce, size);
+ stage2->ce_flags = create_ce_flags(namelen, 2);
+ if (add_cache_entry(stage2, ADD_CACHE_OK_TO_ADD) < 0)
+ die("cannot merge index and our head tree");
+
+ /* We are done with this name, so skip to next name */
+ while (i < active_nr &&
+ ce_namelen(active_cache[i]) == namelen &&
+ !memcmp(active_cache[i]->name, ce->name, namelen))
+ i++;
+ i--; /* compensate for the loop control */
+ }
}
/*
if (!a)
return 0;
- if (old && same(old, a))
- *a = *old;
- a->ce_flags &= ~htons(CE_STAGEMASK);
- *dst++ = a;
- return 1;
+ if (old && same(old, a)) {
+ *dst++ = old;
+ return 1;
+ }
+ return merged_entry(a, NULL, dst);
}
static void check_updates(struct cache_entry **src, int nr)
unsigned short mask = htons(CE_UPDATE);
while (nr--) {
struct cache_entry *ce = *src++;
+ if (!ce->ce_mode) {
+ if (update)
+ unlink(ce->name);
+ continue;
+ }
if (ce->ce_flags & mask) {
ce->ce_flags &= ~mask;
if (update)
check_updates(active_cache, active_nr);
}
-static char *read_tree_usage = "git-read-tree (<sha> | -m <sha1> [<sha2> [<sha3>]])";
+static int read_cache_unmerged(void)
+{
+ int i, deleted;
+ struct cache_entry **dst;
+
+ read_cache();
+ dst = active_cache;
+ deleted = 0;
+ for (i = 0; i < active_nr; i++) {
+ struct cache_entry *ce = active_cache[i];
+ if (ce_stage(ce)) {
+ deleted++;
+ continue;
+ }
+ if (deleted)
+ *dst = ce;
+ dst++;
+ }
+ active_nr -= deleted;
+ return deleted;
+}
+
+static char *read_tree_usage = "git-read-tree (<sha> | -m [-u] <sha1> [<sha2> [<sha3>]])";
static struct cache_file cache_file;
int main(int argc, char **argv)
{
- int i, newfd, merge;
+ int i, newfd, merge, reset, emu23;
unsigned char sha1[20];
newfd = hold_index_file_for_update(&cache_file, get_index_file());
die("unable to create new cachefile");
merge = 0;
+ reset = 0;
+ emu23 = 0;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
continue;
}
+ /* This differs from "-m" in that we'll silently ignore unmerged entries */
+ if (!strcmp(arg, "--reset")) {
+ if (stage || merge || emu23)
+ usage(read_tree_usage);
+ reset = 1;
+ merge = 1;
+ stage = 1;
+ read_cache_unmerged();
+ }
+
/* "-m" stands for "merge", meaning we start in stage 1 */
if (!strcmp(arg, "-m")) {
- int i;
- if (stage)
- die("-m needs to come first");
- read_cache();
- for (i = 0; i < active_nr; i++) {
- if (ce_stage(active_cache[i]))
- die("you need to resolve your current index first");
- }
+ if (stage || merge || emu23)
+ usage(read_tree_usage);
+ if (read_cache_unmerged())
+ die("you need to resolve your current index first");
stage = 1;
merge = 1;
continue;
}
+
+ /* "-emu23" uses 3-way merge logic to perform fast-forward */
+ if (!strcmp(arg, "--emu23")) {
+ if (stage || merge || emu23)
+ usage(read_tree_usage);
+ if (read_cache_unmerged())
+ die("you need to resolve your current index first");
+ merge = emu23 = stage = 1;
+ continue;
+ }
+
if (get_sha1(arg, sha1) < 0)
usage(read_tree_usage);
if (stage > 3)
die("failed to unpack tree object %s", arg);
stage++;
}
+ if (update && !merge)
+ usage(read_tree_usage);
if (merge) {
static const merge_fn_t merge_function[] = {
[1] = oneway_merge,
[2] = twoway_merge,
[3] = threeway_merge,
};
+ merge_fn_t fn;
+
if (stage < 2 || stage > 4)
die("just how do you expect me to merge %d trees?", stage-1);
- merge_cache(active_cache, active_nr, merge_function[stage-1]);
+ if (emu23 && stage != 3)
+ die("--emu23 takes only two trees");
+ fn = merge_function[stage-1];
+ if (stage == 3 && emu23) {
+ setup_emu23();
+ fn = merge_function[3];
+ }
+ merge_cache(active_cache, active_nr, fn);
}
if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
projects / git.git / blobdiff