return buf;
}
-static int entry_compare(struct name_entry *a, struct name_entry *b)
-{
- return df_name_compare(
- a->path, tree_entry_len(a->path, a->sha1), a->mode,
- b->path, tree_entry_len(b->path, b->sha1), b->mode);
-}
-
static void entry_clear(struct name_entry *a)
{
memset(a, 0, sizeof(*a));
return path;
}
+struct tree_desc_skip {
+ struct tree_desc_skip *prev;
+ const void *ptr;
+};
+
+struct tree_desc_x {
+ struct tree_desc d;
+ struct tree_desc_skip *skip;
+};
+
+static int name_compare(const char *a, int a_len,
+ const char *b, int b_len)
+{
+ int len = (a_len < b_len) ? a_len : b_len;
+ int cmp = memcmp(a, b, len);
+ if (cmp)
+ return cmp;
+ return (a_len - b_len);
+}
+
+static int check_entry_match(const char *a, int a_len, const char *b, int b_len)
+{
+ /*
+ * The caller wants to pick *a* from a tree or nothing.
+ * We are looking at *b* in a tree.
+ *
+ * (0) If a and b are the same name, we are trivially happy.
+ *
+ * There are three possibilities where *a* could be hiding
+ * behind *b*.
+ *
+ * (1) *a* == "t", *b* == "ab" i.e. *b* sorts earlier than *a* no
+ * matter what.
+ * (2) *a* == "t", *b* == "t-2" and "t" is a subtree in the tree;
+ * (3) *a* == "t-2", *b* == "t" and "t-2" is a blob in the tree.
+ *
+ * Otherwise we know *a* won't appear in the tree without
+ * scanning further.
+ */
+
+ int cmp = name_compare(a, a_len, b, b_len);
+
+ /* Most common case first -- reading sync'd trees */
+ if (!cmp)
+ return cmp;
+
+ if (0 < cmp) {
+ /* a comes after b; it does not matter if it is case (3)
+ if (b_len < a_len && !memcmp(a, b, b_len) && a[b_len] < '/')
+ return 1;
+ */
+ return 1; /* keep looking */
+ }
+
+ /* b comes after a; are we looking at case (2)? */
+ if (a_len < b_len && !memcmp(a, b, a_len) && b[a_len] < '/')
+ return 1; /* keep looking */
+
+ return -1; /* a cannot appear in the tree */
+}
+
+/*
+ * From the extended tree_desc, extract the first name entry, while
+ * paying attention to the candidate "first" name. Most importantly,
+ * when looking for an entry, if there are entries that sorts earlier
+ * in the tree object representation than that name, skip them and
+ * process the named entry first. We will remember that we haven't
+ * processed the first entry yet, and in the later call skip the
+ * entry we processed early when update_extended_entry() is called.
+ *
+ * E.g. if the underlying tree object has these entries:
+ *
+ * blob "t-1"
+ * blob "t-2"
+ * tree "t"
+ * blob "t=1"
+ *
+ * and the "first" asks for "t", remember that we still need to
+ * process "t-1" and "t-2" but extract "t". After processing the
+ * entry "t" from this call, the caller will let us know by calling
+ * update_extended_entry() that we can remember "t" has been processed
+ * already.
+ */
+
+static void extended_entry_extract(struct tree_desc_x *t,
+ struct name_entry *a,
+ const char *first,
+ int first_len)
+{
+ const char *path;
+ int len;
+ struct tree_desc probe;
+ struct tree_desc_skip *skip;
+
+ /*
+ * Extract the first entry from the tree_desc, but skip the
+ * ones that we already returned in earlier rounds.
+ */
+ while (1) {
+ if (!t->d.size) {
+ entry_clear(a);
+ break; /* not found */
+ }
+ entry_extract(&t->d, a);
+ for (skip = t->skip; skip; skip = skip->prev)
+ if (a->path == skip->ptr)
+ break; /* found */
+ if (!skip)
+ break;
+ /* We have processed this entry already. */
+ update_tree_entry(&t->d);
+ }
+
+ if (!first || !a->path)
+ return;
+
+ /*
+ * The caller wants "first" from this tree, or nothing.
+ */
+ path = a->path;
+ len = tree_entry_len(a->path, a->sha1);
+ switch (check_entry_match(first, first_len, path, len)) {
+ case -1:
+ entry_clear(a);
+ case 0:
+ return;
+ default:
+ break;
+ }
+
+ /*
+ * We need to look-ahead -- we suspect that a subtree whose
+ * name is "first" may be hiding behind the current entry "path".
+ */
+ probe = t->d;
+ while (probe.size) {
+ entry_extract(&probe, a);
+ path = a->path;
+ len = tree_entry_len(a->path, a->sha1);
+ switch (check_entry_match(first, first_len, path, len)) {
+ case -1:
+ entry_clear(a);
+ case 0:
+ return;
+ default:
+ update_tree_entry(&probe);
+ break;
+ }
+ /* keep looking */
+ }
+ entry_clear(a);
+}
+
+static void update_extended_entry(struct tree_desc_x *t, struct name_entry *a)
+{
+ if (t->d.entry.path == a->path) {
+ update_tree_entry(&t->d);
+ } else {
+ /* we have returned this entry early */
+ struct tree_desc_skip *skip = xmalloc(sizeof(*skip));
+ skip->ptr = a->path;
+ skip->prev = t->skip;
+ t->skip = skip;
+ }
+}
+
+static void free_extended_entry(struct tree_desc_x *t)
+{
+ struct tree_desc_skip *p, *s;
+
+ for (s = t->skip; s; s = p) {
+ p = s->prev;
+ free(s);
+ }
+}
+
int traverse_trees(int n, struct tree_desc *t, struct traverse_info *info)
{
int ret = 0;
struct name_entry *entry = xmalloc(n*sizeof(*entry));
+ int i;
+ struct tree_desc_x *tx = xcalloc(n, sizeof(*tx));
+
+ for (i = 0; i < n; i++)
+ tx[i].d = t[i];
for (;;) {
- unsigned long mask = 0;
- unsigned long dirmask = 0;
- int i, last;
+ unsigned long mask, dirmask;
+ const char *first = NULL;
+ int first_len = 0;
+ struct name_entry *e;
+ int len;
+
+ for (i = 0; i < n; i++) {
+ e = entry + i;
+ extended_entry_extract(tx + i, e, NULL, 0);
+ }
- last = -1;
+ /*
+ * A tree may have "t-2" at the current location even
+ * though it may have "t" that is a subtree behind it,
+ * and another tree may return "t". We want to grab
+ * all "t" from all trees to match in such a case.
+ */
for (i = 0; i < n; i++) {
- if (!t[i].size)
+ e = entry + i;
+ if (!e->path)
continue;
- entry_extract(t+i, entry+i);
- if (last >= 0) {
- int cmp = entry_compare(entry+i, entry+last);
-
- /*
- * Is the new name bigger than the old one?
- * Ignore it
- */
- if (cmp > 0)
+ len = tree_entry_len(e->path, e->sha1);
+ if (!first) {
+ first = e->path;
+ first_len = len;
+ continue;
+ }
+ if (name_compare(e->path, len, first, first_len) < 0) {
+ first = e->path;
+ first_len = len;
+ }
+ }
+
+ if (first) {
+ for (i = 0; i < n; i++) {
+ e = entry + i;
+ extended_entry_extract(tx + i, e, first, first_len);
+ /* Cull the ones that are not the earliest */
+ if (!e->path)
continue;
- /*
- * Is the new name smaller than the old one?
- * Ignore all old ones
- */
- if (cmp < 0)
- mask = 0;
+ len = tree_entry_len(e->path, e->sha1);
+ if (name_compare(e->path, len, first, first_len))
+ entry_clear(e);
}
+ }
+
+ /* Now we have in entry[i] the earliest name from the trees */
+ mask = 0;
+ dirmask = 0;
+ for (i = 0; i < n; i++) {
+ if (!entry[i].path)
+ continue;
mask |= 1ul << i;
if (S_ISDIR(entry[i].mode))
dirmask |= 1ul << i;
- last = i;
}
if (!mask)
break;
- dirmask &= mask;
-
- /*
- * Clear all the unused name-entries.
- */
- for (i = 0; i < n; i++) {
- if (mask & (1ul << i))
- continue;
- entry_clear(entry + i);
- }
ret = info->fn(n, mask, dirmask, entry, info);
if (ret < 0)
break;
- if (ret)
- mask &= ret;
+ mask &= ret;
ret = 0;
- for (i = 0; i < n; i++) {
+ for (i = 0; i < n; i++)
if (mask & (1ul << i))
- update_tree_entry(t + i);
- }
+ update_extended_entry(tx + i, entry + i);
}
free(entry);
+ for (i = 0; i < n; i++)
+ free_extended_entry(tx + i);
+ free(tx);
return ret;
}
if (name[0] == '\0') {
hashcpy(sha1, root);
+ free(tree);
return 0;
}