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authorJunio C Hamano <gitster@pobox.com>2010-01-07 14:59:54 -0800
committerJunio C Hamano <gitster@pobox.com>2010-01-07 14:59:54 -0800
commitda165f470ede6540873d33cb8bc2ff8e13c60520 (patch)
treef17582a9b57a806bea9ba48c128b48f681baf692 /unpack-trees.c
parentcee2d6ae6379e7c76e602d55ccc1d4babc1979c0 (diff)
downloadgit-da165f470ede6540873d33cb8bc2ff8e13c60520.tar.gz
unpack-trees.c: prepare for looking ahead in the index
This prepares but does not yet implement a look-ahead in the index entries when traverse-trees.c decides to give us tree entries in an order that does not match what is in the index. A case where a look-ahead in the index is necessary happens when merging branch B into branch A while the index matches the current branch A, using a tree O as their common ancestor, and these three trees looks like this: O A B t t t-i t-i t-i t-j t-j t/1 t/2 The traverse_trees() function gets "t", "t-i" and "t" from trees O, A and B first, and notices that A may have a matching "t" behind "t-i" and "t-j" (indeed it does), and tells A to give that entry instead. After unpacking blob "t" from tree B (as it hasn't changed since O in B and A removed it, it will result in its removal), it descends into directory "t/". The side that walked index in parallel to the tree traversal used to be implemented with one pointer, o->pos, that points at the next index entry to be processed. When this happens, the pointer o->pos still points at "t-i" that is the first entry. We should be able to skip "t-i" and "t-j" and locate "t/1" from the index while the recursive invocation of traverse_trees() walks and match entries found there, and later come back to process "t-i". While that look-ahead is not implemented yet, this adds a flag bit, CE_UNPACKED, to mark the entries in the index that has already been processed. o->pos pointer has been renamed to o->cache_bottom and it points at the first entry that may still need to be processed. Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'unpack-trees.c')
-rw-r--r--unpack-trees.c216
1 files changed, 170 insertions, 46 deletions
diff --git a/unpack-trees.c b/unpack-trees.c
index 7413ff0b93..685adb4b77 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -126,18 +126,109 @@ static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_o
return ret;
}
-static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
+static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+ ce->ce_flags |= CE_UNPACKED;
+
+ if (o->cache_bottom < o->src_index->cache_nr &&
+ o->src_index->cache[o->cache_bottom] == ce) {
+ int bottom = o->cache_bottom;
+ while (bottom < o->src_index->cache_nr &&
+ o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
+ bottom++;
+ o->cache_bottom = bottom;
+ }
+}
+
+static void mark_all_ce_unused(struct index_state *index)
+{
+ int i;
+ for (i = 0; i < index->cache_nr; i++)
+ index->cache[i]->ce_flags &= ~CE_UNPACKED;
+}
+
+static int locate_in_src_index(struct cache_entry *ce,
+ struct unpack_trees_options *o)
+{
+ struct index_state *index = o->src_index;
+ int len = ce_namelen(ce);
+ int pos = index_name_pos(index, ce->name, len);
+ if (pos < 0)
+ pos = -1 - pos;
+ return pos;
+}
+
+/*
+ * We call unpack_index_entry() with an unmerged cache entry
+ * only in diff-index, and it wants a single callback. Skip
+ * the other unmerged entry with the same name.
+ */
+static void mark_ce_used_same_name(struct cache_entry *ce,
+ struct unpack_trees_options *o)
+{
+ struct index_state *index = o->src_index;
+ int len = ce_namelen(ce);
+ int pos;
+
+ for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
+ struct cache_entry *next = index->cache[pos];
+ if (len != ce_namelen(next) ||
+ memcmp(ce->name, next->name, len))
+ break;
+ mark_ce_used(next, o);
+ }
+}
+
+static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
+{
+ const struct index_state *index = o->src_index;
+ int pos = o->cache_bottom;
+
+ while (pos < index->cache_nr) {
+ struct cache_entry *ce = index->cache[pos];
+ if (!(ce->ce_flags & CE_UNPACKED))
+ return ce;
+ pos++;
+ }
+ return NULL;
+}
+
+static void add_same_unmerged(struct cache_entry *ce,
+ struct unpack_trees_options *o)
+{
+ struct index_state *index = o->src_index;
+ int len = ce_namelen(ce);
+ int pos = index_name_pos(index, ce->name, len);
+
+ if (0 <= pos)
+ die("programming error in a caller of mark_ce_used_same_name");
+ for (pos = -pos - 1; pos < index->cache_nr; pos++) {
+ struct cache_entry *next = index->cache[pos];
+ if (len != ce_namelen(next) ||
+ memcmp(ce->name, next->name, len))
+ break;
+ add_entry(o, next, 0, 0);
+ mark_ce_used(next, o);
+ }
+}
+
+static int unpack_index_entry(struct cache_entry *ce,
+ struct unpack_trees_options *o)
{
struct cache_entry *src[5] = { ce, NULL, };
+ int ret;
- o->pos++;
+ mark_ce_used(ce, o);
if (ce_stage(ce)) {
if (o->skip_unmerged) {
add_entry(o, ce, 0, 0);
return 0;
}
}
- return call_unpack_fn(src, o);
+ ret = call_unpack_fn(src, o);
+ if (ce_stage(ce))
+ mark_ce_used_same_name(ce, o);
+ return ret;
}
static int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
@@ -212,6 +303,20 @@ static int compare_entry(const struct cache_entry *ce, const struct traverse_inf
return ce_namelen(ce) > traverse_path_len(info, n);
}
+static int ce_in_traverse_path(const struct cache_entry *ce,
+ const struct traverse_info *info)
+{
+ if (!info->prev)
+ return 1;
+ if (do_compare_entry(ce, info->prev, &info->name))
+ return 0;
+ /*
+ * If ce (blob) is the same name as the path (which is a tree
+ * we will be descending into), it won't be inside it.
+ */
+ return (info->pathlen < ce_namelen(ce));
+}
+
static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
{
int len = traverse_path_len(info, n);
@@ -300,23 +405,27 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
/* Are we supposed to look at the index too? */
if (o->merge) {
- while (o->pos < o->src_index->cache_nr) {
- struct cache_entry *ce = o->src_index->cache[o->pos];
- int cmp = compare_entry(ce, info, p);
+ while (1) {
+ struct cache_entry *ce = next_cache_entry(o);
+ int cmp;
+ if (!ce)
+ break;
+ cmp = compare_entry(ce, info, p);
if (cmp < 0) {
if (unpack_index_entry(ce, o) < 0)
return unpack_failed(o, NULL);
continue;
}
if (!cmp) {
- o->pos++;
if (ce_stage(ce)) {
/*
- * If we skip unmerged index entries, we'll skip this
- * entry *and* the tree entries associated with it!
+ * If we skip unmerged index
+ * entries, we'll skip this
+ * entry *and* the tree
+ * entries associated with it!
*/
if (o->skip_unmerged) {
- add_entry(o, ce, 0, 0);
+ add_same_unmerged(ce, o);
return mask;
}
}
@@ -329,6 +438,13 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
return -1;
+ if (src[0]) {
+ if (ce_stage(src[0]))
+ mark_ce_used_same_name(src[0], o);
+ else
+ mark_ce_used(src[0], o);
+ }
+
/* Now handle any directories.. */
if (dirmask) {
unsigned long conflicts = mask & ~dirmask;
@@ -345,11 +461,13 @@ static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, str
matches = cache_tree_matches_traversal(o->src_index->cache_tree,
names, info);
/*
- * Everything under the name matches. Adjust o->pos to
- * skip the entire hierarchy.
+ * Everything under the name matches; skip the
+ * entire hierarchy. diff_index_cached codepath
+ * special cases D/F conflicts in such a way that
+ * it does not do any look-ahead, so this is safe.
*/
if (matches) {
- o->pos += matches;
+ o->cache_bottom += matches;
return mask;
}
}
@@ -382,11 +500,10 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
memset(&o->result, 0, sizeof(o->result));
o->result.initialized = 1;
- if (o->src_index) {
- o->result.timestamp.sec = o->src_index->timestamp.sec;
- o->result.timestamp.nsec = o->src_index->timestamp.nsec;
- }
+ o->result.timestamp.sec = o->src_index->timestamp.sec;
+ o->result.timestamp.nsec = o->src_index->timestamp.nsec;
o->merge_size = len;
+ mark_all_ce_unused(o->src_index);
if (!dfc)
dfc = xcalloc(1, cache_entry_size(0));
@@ -400,18 +517,38 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
info.fn = unpack_callback;
info.data = o;
+ if (o->prefix) {
+ /*
+ * Unpack existing index entries that sort before the
+ * prefix the tree is spliced into. Note that o->merge
+ * is always true in this case.
+ */
+ while (1) {
+ struct cache_entry *ce = next_cache_entry(o);
+ if (!ce)
+ break;
+ if (ce_in_traverse_path(ce, &info))
+ break;
+ if (unpack_index_entry(ce, o) < 0)
+ goto return_failed;
+ }
+ }
+
if (traverse_trees(len, t, &info) < 0)
- return unpack_failed(o, NULL);
+ goto return_failed;
}
/* Any left-over entries in the index? */
if (o->merge) {
- while (o->pos < o->src_index->cache_nr) {
- struct cache_entry *ce = o->src_index->cache[o->pos];
+ while (1) {
+ struct cache_entry *ce = next_cache_entry(o);
+ if (!ce)
+ break;
if (unpack_index_entry(ce, o) < 0)
- return unpack_failed(o, NULL);
+ goto return_failed;
}
}
+ mark_all_ce_unused(o->src_index);
if (o->trivial_merges_only && o->nontrivial_merge)
return unpack_failed(o, "Merge requires file-level merging");
@@ -421,6 +558,10 @@ int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options
if (o->dst_index)
*o->dst_index = o->result;
return ret;
+
+return_failed:
+ mark_all_ce_unused(o->src_index);
+ return unpack_failed(o, NULL);
}
/* Here come the merge functions */
@@ -522,7 +663,9 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
* in that directory.
*/
namelen = strlen(ce->name);
- for (i = o->pos; i < o->src_index->cache_nr; i++) {
+ for (i = locate_in_src_index(ce, o);
+ i < o->src_index->cache_nr;
+ i++) {
struct cache_entry *ce2 = o->src_index->cache[i];
int len = ce_namelen(ce2);
if (len < namelen ||
@@ -530,12 +673,14 @@ static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
ce2->name[namelen] != '/')
break;
/*
- * ce2->name is an entry in the subdirectory.
+ * ce2->name is an entry in the subdirectory to be
+ * removed.
*/
if (!ce_stage(ce2)) {
if (verify_uptodate(ce2, o))
return -1;
add_entry(o, ce2, CE_REMOVE, 0);
+ mark_ce_used(ce2, o);
}
cnt++;
}
@@ -591,7 +736,6 @@ static int verify_absent(struct cache_entry *ce, const char *action,
return 0;
if (!lstat(ce->name, &st)) {
- int ret;
int dtype = ce_to_dtype(ce);
struct cache_entry *result;
@@ -619,28 +763,8 @@ static int verify_absent(struct cache_entry *ce, const char *action,
* files that are in "foo/" we would lose
* them.
*/
- ret = verify_clean_subdirectory(ce, action, o);
- if (ret < 0)
- return ret;
-
- /*
- * If this removed entries from the index,
- * what that means is:
- *
- * (1) the caller unpack_callback() saw path/foo
- * in the index, and it has not removed it because
- * it thinks it is handling 'path' as blob with
- * D/F conflict;
- * (2) we will return "ok, we placed a merged entry
- * in the index" which would cause o->pos to be
- * incremented by one;
- * (3) however, original o->pos now has 'path/foo'
- * marked with "to be removed".
- *
- * We need to increment it by the number of
- * deleted entries here.
- */
- o->pos += ret;
+ if (verify_clean_subdirectory(ce, action, o) < 0)
+ return -1;
return 0;
}