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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-19 03:21:34 (GMT)
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-19 03:21:34 (GMT)
commit12676608fefd6b148bd9fd4cbd4eb6c2ff3e15e9 (patch)
tree664d4b3dc518c63e0b5b3e815126e72fe40dc224 /read-cache.c
parent3d958064e0f26f3cbd5b201f295c182b6aa119da (diff)
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Re-implement "check_file_directory_conflict()"
This is (imho) more readable, and is also a lot faster. The expense of looking up sub-directory beginnings was killing us on things like "git-diff-cache", even though that one didn't even care at all about the file vs directory conflicts. We really only care when somebody tries to add a conflicting name to stage 0. We should go through the conflict rules more carefully some day.
Diffstat (limited to 'read-cache.c')
-rw-r--r--read-cache.c177
1 files changed, 88 insertions, 89 deletions
diff --git a/read-cache.c b/read-cache.c
index e9618f0..4b8348c 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -171,107 +171,106 @@ int ce_same_name(struct cache_entry *a, struct cache_entry *b)
return ce_namelen(b) == len && !memcmp(a->name, b->name, len);
}
-/* We may be in a situation where we already have path/file and path
- * is being added, or we already have path and path/file is being
- * added. Either one would result in a nonsense tree that has path
- * twice when git-write-tree tries to write it out. Prevent it.
- *
- * If ok-to-replace is specified, we remove the conflicting entries
- * from the cache so the caller should recompute the insert position.
- * When this happens, we return non-zero.
+/*
+ * Do we have another file that has the beginning components being a
+ * proper superset of the name we're trying to add?
*/
-static int check_file_directory_conflict(const struct cache_entry *ce,
- int ok_to_replace)
+static int has_file_name(const struct cache_entry *ce, int pos, int ok_to_replace)
{
- int pos, replaced = 0;
- const char *path = ce->name;
- int namelen = strlen(path);
- int stage = ce_stage(ce);
- char *pathbuf = xmalloc(namelen + 1);
- char *cp;
+ int retval = 0;
+ int len = ce_namelen(ce);
+ const char *name = ce->name;
- memcpy(pathbuf, path, namelen + 1);
+ while (pos < active_nr) {
+ struct cache_entry *p = active_cache[pos++];
- /*
- * We are inserting path/file. Do they have path registered at
- * the same stage? We need to do this for all the levels of our
- * subpath.
- */
- cp = pathbuf;
- while (1) {
- char *ep = strchr(cp, '/');
- int len;
- if (!ep)
+ if (len >= ce_namelen(p))
break;
- *ep = 0; /* first cut it at slash */
- len = ep - pathbuf;
- pos = cache_name_pos(pathbuf,
- ntohs(create_ce_flags(len, stage)));
- if (0 <= pos) {
- /* Our leading path component is registered as a file,
- * and we are trying to make it a directory. This is
- * bad.
- */
- if (!ok_to_replace) {
- free(pathbuf);
- return -1;
- }
- fprintf(stderr, "removing file '%s' to replace it with a directory to create '%s'.\n", pathbuf, path);
- remove_cache_entry_at(pos);
- replaced = 1;
- }
- *ep = '/'; /* then restore it and go downwards */
- cp = ep + 1;
+ if (memcmp(name, p->name, len))
+ break;
+ if (p->name[len] != '/')
+ continue;
+fprintf(stderr, "conflict: %s %s\n", ce->name, p->name);
+ retval = -1;
+ if (!ok_to_replace)
+ break;
+ remove_cache_entry_at(--pos);
}
- free(pathbuf);
+ return retval;
+}
- /* Do we have an entry in the cache that makes our path a prefix
- * of it? That is, are we creating a file where they already expect
- * a directory there?
- */
- pos = cache_name_pos(path,
- ntohs(create_ce_flags(namelen, stage)));
+/*
+ * Do we have another file with a pathname that is a proper
+ * subset of the name we're trying to add?
+ */
+static int has_dir_name(const struct cache_entry *ce, int pos, int ok_to_replace)
+{
+ int retval = 0;
+ const char *name = ce->name;
+ const char *slash = name + ce_namelen(ce);
- /* (0 <= pos) cannot happen because add_cache_entry()
- * should have taken care of that case.
- */
- pos = -pos-1;
+ for (;;) {
+ int len;
- /* pos would point at an existing entry that would come immediately
- * after our path. It could be the same as our path in higher stage,
- * or different path but in a lower stage.
- *
- * E.g. when we are inserting path at stage 2,
- *
- * 1 path
- * pos-> 3 path
- * 2 path/file1
- * 3 path/file1
- * 2 path/file2
- * 2 patho
- *
- * We need to examine pos, ignore it because it is at different
- * stage, examine next to find the path/file at stage 2, and
- * complain. We need to do this until we are not the leading
- * path of an existing entry anymore.
- */
+ for (;;) {
+ if (*--slash == '/')
+ break;
+ if (slash <= ce->name)
+ return retval;
+ }
+ len = slash - name;
- while (pos < active_nr) {
- struct cache_entry *other = active_cache[pos];
- if (strncmp(other->name, path, namelen))
- break; /* it is not our "subdirectory" anymore */
- if ((ce_stage(other) == stage) &&
- other->name[namelen] == '/') {
- if (!ok_to_replace)
- return -1;
- fprintf(stderr, "removing file '%s' under '%s' to be replaced with a file\n", other->name, path);
+ pos = cache_name_pos(name, len);
+ if (pos >= 0) {
+ retval = -1;
+ if (ok_to_replace)
+ break;
remove_cache_entry_at(pos);
- replaced = 1;
- continue; /* cycle without updating pos */
+ continue;
+ }
+
+ /*
+ * Trivial optimization: if we find an entry that
+ * already matches the sub-directory, then we know
+ * we're ok, and we can exit
+ */
+ pos = -pos-1;
+ if (pos < active_nr) {
+ struct cache_entry *p = active_cache[pos];
+ if (ce_namelen(p) <= len)
+ continue;
+ if (p->name[len] != '/')
+ continue;
+ if (memcmp(p->name, name, len))
+ continue;
+ break;
}
- pos++;
}
- return replaced;
+ return retval;
+}
+
+/* We may be in a situation where we already have path/file and path
+ * is being added, or we already have path and path/file is being
+ * added. Either one would result in a nonsense tree that has path
+ * twice when git-write-tree tries to write it out. Prevent it.
+ *
+ * If ok-to-replace is specified, we remove the conflicting entries
+ * from the cache so the caller should recompute the insert position.
+ * When this happens, we return non-zero.
+ */
+static int check_file_directory_conflict(const struct cache_entry *ce, int pos, int ok_to_replace)
+{
+ /*
+ * We check if the path is a sub-path of a subsequent pathname
+ * first, since removing those will not change the position
+ * in the array
+ */
+ int retval = has_file_name(ce, pos, ok_to_replace);
+ /*
+ * Then check if the path might have a clashing sub-directory
+ * before it.
+ */
+ return retval + has_dir_name(ce, pos, ok_to_replace);
}
int add_cache_entry(struct cache_entry *ce, int option)
@@ -304,7 +303,7 @@ int add_cache_entry(struct cache_entry *ce, int option)
if (!ok_to_add)
return -1;
- if (check_file_directory_conflict(ce, ok_to_replace)) {
+ if (!ce_stage(ce) && check_file_directory_conflict(ce, pos, ok_to_replace)) {
if (!ok_to_replace)
return -1;
pos = cache_name_pos(ce->name, ntohs(ce->ce_flags));