remote: die if branch is not found in repository

In a subsequent commit, we would like external-facing functions to be
able to accept "struct repository" and "struct branch" as a pair. This
is useful for functions like pushremote_for_branch(), which need to take
values from the remote_state and branch, even if branch == NULL.
However, a caller may supply an unrelated repository and branch, which
is not supported behavior.

To prevent misuse, add a die_on_missing_branch() helper function that
dies if a given branch is not from a given repository. Speed up the
existence check by replacing the branches list with a branches_hash
hashmap.

Like read_config(), die_on_missing_branch() is only called from
non-static functions; static functions are less prone to misuse because
they have strong conventions for keeping remote_state and branch in
sync.

Signed-off-by: Glen Choo <chooglen@google.com>
Reviewed-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/remote.c b/remote.c
index 88697e7e6d33665d87ab57a7d671a9640e21b5a2..c97c626eaa83908408848733d2db32cbbe097931 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -166,25 +166,74 @@ static void add_merge(struct branch *branch, const char *name)
        branch->merge_name[branch->merge_nr++] = name;
 }
 
+struct branches_hash_key {
+       const char *str;
+       int len;
+};
+
+static int branches_hash_cmp(const void *unused_cmp_data,
+                            const struct hashmap_entry *eptr,
+                            const struct hashmap_entry *entry_or_key,
+                            const void *keydata)
+{
+       const struct branch *a, *b;
+       const struct branches_hash_key *key = keydata;
+
+       a = container_of(eptr, const struct branch, ent);
+       b = container_of(entry_or_key, const struct branch, ent);
+
+       if (key)
+               return strncmp(a->name, key->str, key->len) ||
+                      a->name[key->len];
+       else
+               return strcmp(a->name, b->name);
+}
+
+static struct branch *find_branch(struct remote_state *remote_state,
+                                 const char *name, size_t len)
+{
+       struct branches_hash_key lookup;
+       struct hashmap_entry lookup_entry, *e;
+
+       if (!len)
+               len = strlen(name);
+
+       lookup.str = name;
+       lookup.len = len;
+       hashmap_entry_init(&lookup_entry, memhash(name, len));
+
+       e = hashmap_get(&remote_state->branches_hash, &lookup_entry, &lookup);
+       if (e)
+               return container_of(e, struct branch, ent);
+
+       return NULL;
+}
+
+static void die_on_missing_branch(struct repository *repo,
+                                 struct branch *branch)
+{
+       /* branch == NULL is always valid because it represents detached HEAD. */
+       if (branch &&
+           branch != find_branch(repo->remote_state, branch->name, 0))
+               die("branch %s was not found in the repository", branch->name);
+}
+
 static struct branch *make_branch(struct remote_state *remote_state,
                                  const char *name, size_t len)
 {
        struct branch *ret;
-       int i;
 
-       for (i = 0; i < remote_state->branches_nr; i++) {
-               if (!strncmp(name, remote_state->branches[i]->name, len) &&
-                   !remote_state->branches[i]->name[len])
-                       return remote_state->branches[i];
-       }
+       ret = find_branch(remote_state, name, len);
+       if (ret)
+               return ret;
 
-       ALLOC_GROW(remote_state->branches, remote_state->branches_nr + 1,
-                  remote_state->branches_alloc);
        CALLOC_ARRAY(ret, 1);
-       remote_state->branches[remote_state->branches_nr++] = ret;
        ret->name = xstrndup(name, len);
        ret->refname = xstrfmt("refs/heads/%s", ret->name);
 
+       hashmap_entry_init(&ret->ent, memhash(name, len));
+       if (hashmap_put_entry(&remote_state->branches_hash, ret, ent))
+               BUG("hashmap_put overwrote entry after hashmap_get returned NULL");
        return ret;
 }
 
@@ -500,6 +549,8 @@ static const char *remotes_remote_for_branch(struct remote_state *remote_state,
 const char *remote_for_branch(struct branch *branch, int *explicit)
 {
        read_config(the_repository);
+       die_on_missing_branch(the_repository, branch);
+
        return remotes_remote_for_branch(the_repository->remote_state, branch,
                                         explicit);
 }
@@ -524,6 +575,8 @@ remotes_pushremote_for_branch(struct remote_state *remote_state,
 const char *pushremote_for_branch(struct branch *branch, int *explicit)
 {
        read_config(the_repository);
+       die_on_missing_branch(the_repository, branch);
+
        return remotes_pushremote_for_branch(the_repository->remote_state,
                                             branch, explicit);
 }
@@ -534,6 +587,8 @@ static struct remote *remotes_remote_get(struct remote_state *remote_state,
 const char *remote_ref_for_branch(struct branch *branch, int for_push)
 {
        read_config(the_repository);
+       die_on_missing_branch(the_repository, branch);
+
        if (branch) {
                if (!for_push) {
                        if (branch->merge_nr) {
@@ -1879,6 +1934,8 @@ static const char *branch_get_push_1(struct remote_state *remote_state,
 const char *branch_get_push(struct branch *branch, struct strbuf *err)
 {
        read_config(the_repository);
+       die_on_missing_branch(the_repository, branch);
+
        if (!branch)
                return error_buf(err, _("HEAD does not point to a branch"));
 
@@ -2652,6 +2709,7 @@ struct remote_state *remote_state_new(void)
        memset(r, 0, sizeof(*r));
 
        hashmap_init(&r->remotes_hash, remotes_hash_cmp, NULL, 0);
+       hashmap_init(&r->branches_hash, branches_hash_cmp, NULL, 0);
        return r;
 }
 
@@ -2667,11 +2725,5 @@ void remote_state_clear(struct remote_state *remote_state)
        remote_state->remotes_nr = 0;
 
        hashmap_clear_and_free(&remote_state->remotes_hash, struct remote, ent);
-
-       for (i = 0; i < remote_state->branches_nr; i++) {
-               FREE_AND_NULL(remote_state->branches[i]);
-       }
-       FREE_AND_NULL(remote_state->branches);
-       remote_state->branches_alloc = 0;
-       remote_state->branches_nr = 0;
+       hashmap_clear_and_free(&remote_state->branches_hash, struct remote, ent);
 }

diff --git a/remote.h b/remote.h
index 85a730b8ef3c966cd1e533165267f724ef8250a8..4a1209ae2c800d1fc07b7905b26d615d28eee924 100644 (file)
--- a/remote.h
+++ b/remote.h
@@ -43,9 +43,7 @@ struct remote_state {
        int remotes_nr;
        struct hashmap remotes_hash;
 
-       struct branch **branches;
-       int branches_alloc;
-       int branches_nr;
+       struct hashmap branches_hash;
 
        struct branch *current_branch;
        const char *pushremote_name;
@@ -292,6 +290,7 @@ int remote_find_tracking(struct remote *remote, struct refspec_item *refspec);
  * branch_get(name) for "refs/heads/{name}", or with branch_get(NULL) for HEAD.
  */
 struct branch {
+       struct hashmap_entry ent;
 
        /* The short name of the branch. */
        const char *name;