lib/repo-refs: Add ostree_repo_remote_list_collection_refs() API

This parallels ostree_repo_remote_list_refs(), but returns a map of
OstreeCollectionRef → checksum, and includes refs from collection IDs
other than the remote repository’s main collection ID.

Use this in OstreeRepoFinderConfig to ensure that refs are matched
against even if they’re stored in the repository summary file’s
collection map, rather than its main ref map. This fixes false negatives
when searching for refs in some situations.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Closes: #1058
Approved by: cgwalters

apidoc/ostree-experimental-sections.txt

@@ -82,6 +82,7 @@ ostree_repo_get_collection_id
 ostree_repo_set_collection_id
 ostree_validate_collection_id
 ostree_repo_list_collection_refs
+ostree_repo_remote_list_collection_refs
 ostree_repo_set_collection_ref_immediate
 ostree_repo_transaction_set_collection_ref
 </SECTION>

src/libostree/libostree-experimental.sym

@@ -70,6 +70,7 @@ global:
   ostree_repo_list_collection_refs;
   ostree_repo_pull_from_remotes_async;
   ostree_repo_pull_from_remotes_finish;
+  ostree_repo_remote_list_collection_refs;
   ostree_repo_resolve_keyring_for_collection;
   ostree_repo_set_collection_id;
   ostree_repo_set_collection_ref_immediate;

src/libostree/ostree-repo-finder-config.c

@@ -111,7 +111,7 @@ ostree_repo_finder_config_resolve_async (OstreeRepoFinder                  *find
   for (i = 0; i < n_remotes; i++)
     {
       g_autoptr(GError) local_error = NULL;
-      g_autoptr(GHashTable) remote_refs = NULL;  /* (element-type utf8 utf8) */
+      g_autoptr(GHashTable) remote_refs = NULL;  /* (element-type OstreeCollectionRef utf8) */
       const gchar *checksum;
       g_autofree gchar *remote_collection_id = NULL;
 
@@ -127,8 +127,9 @@ ostree_repo_finder_config_resolve_async (OstreeRepoFinder                  *find
           continue;
         }
 
-      if (!ostree_repo_remote_list_refs (parent_repo, remote_name, &remote_refs,
+      if (!ostree_repo_remote_list_collection_refs (parent_repo, remote_name,
-                                         cancellable, &local_error))
+                                                    &remote_refs, cancellable,
+                                                    &local_error))
         {
           g_debug ("Ignoring remote ‘%s’ due to error loading its refs: %s",
                    remote_name, local_error->message);
@@ -139,7 +140,7 @@ ostree_repo_finder_config_resolve_async (OstreeRepoFinder                  *find
       for (j = 0; refs[j] != NULL; j++)
         {
           if (g_strcmp0 (refs[j]->collection_id, remote_collection_id) == 0 &&
-              g_hash_table_lookup_extended (remote_refs, refs[j]->ref_name, NULL, (gpointer *) &checksum))
+              g_hash_table_lookup_extended (remote_refs, refs[j], NULL, (gpointer *) &checksum))
             {
               /* The requested ref is listed in the refs for this remote. Add
                * the remote to the results, and the ref to its

src/libostree/ostree-repo-refs.c

@@ -779,6 +779,126 @@ ostree_repo_remote_list_refs (OstreeRepo       *self,
   return TRUE;
 }
 
+#ifdef OSTREE_ENABLE_EXPERIMENTAL_API
+static gboolean
+remote_list_collection_refs_process_refs (OstreeRepo   *self,
+                                          const gchar  *remote_name,
+                                          const gchar  *summary_collection_id,
+                                          GVariant     *summary_refs,
+                                          GHashTable   *ret_all_refs,
+                                          GError      **error)
+{
+  gsize j, n;
+
+  for (j = 0, n = g_variant_n_children (summary_refs); j < n; j++)
+    {
+      const guchar *csum_bytes;
+      g_autoptr(GVariant) ref_v = NULL, csum_v = NULL;
+      gchar tmp_checksum[OSTREE_SHA256_STRING_LEN + 1];
+      const gchar *ref_name;
+
+      /* Check the ref name. */
+      ref_v = g_variant_get_child_value (summary_refs, j);
+      g_variant_get_child (ref_v, 0, "&s", &ref_name);
+
+      if (!ostree_validate_rev (ref_name, error))
+        return FALSE;
+
+      /* Check the commit checksum. */
+      g_variant_get_child (ref_v, 1, "(t@ay@a{sv})", NULL, &csum_v, NULL);
+
+      csum_bytes = ostree_checksum_bytes_peek_validate (csum_v, error);
+      if (csum_bytes == NULL)
+        return FALSE;
+
+      ostree_checksum_inplace_from_bytes (csum_bytes, tmp_checksum);
+
+      g_hash_table_insert (ret_all_refs,
+                           ostree_collection_ref_new (summary_collection_id, ref_name),
+                           g_strdup (tmp_checksum));
+    }
+
+  return TRUE;
+}
+
+/**
+ * ostree_repo_remote_list_collection_refs:
+ * @self: Repo
+ * @remote_name: Name of the remote.
+ * @out_all_refs: (out) (element-type OstreeCollectionRef utf8): Mapping from collection–ref to checksum
+ * @cancellable: Cancellable
+ * @error: Error
+ *
+ * List refs advertised by @remote_name, including refs which are part of
+ * collections. If the repository at @remote_name has a collection ID set, its
+ * refs will be returned with that collection ID; otherwise, they will be returned
+ * with a %NULL collection ID in each #OstreeCollectionRef key in @out_all_refs.
+ * Any refs for other collections stored in the repository will also be returned.
+ * No filtering is performed.
+ *
+ * Since: 2017.10
+ */
+gboolean
+ostree_repo_remote_list_collection_refs (OstreeRepo    *self,
+                                         const char    *remote_name,
+                                         GHashTable   **out_all_refs,
+                                         GCancellable  *cancellable,
+                                         GError       **error)
+{
+  g_autoptr(GBytes) summary_bytes = NULL;
+  g_autoptr(GHashTable) ret_all_refs = NULL;  /* (element-type OstreeCollectionRef utf8) */
+  g_autoptr(GVariant) summary_v = NULL;
+  g_autoptr(GVariant) additional_metadata_v = NULL;
+  g_autoptr(GVariant) summary_refs = NULL;
+  const char *summary_collection_id;
+  g_autoptr(GVariantIter) summary_collection_map = NULL;
+
+  if (!ostree_repo_remote_fetch_summary (self, remote_name,
+                                         &summary_bytes, NULL,
+                                         cancellable, error))
+    return FALSE;
+
+  if (summary_bytes == NULL)
+    return glnx_throw (error, "Remote refs not available; server has no summary file");
+
+  ret_all_refs = g_hash_table_new_full (ostree_collection_ref_hash,
+                                        ostree_collection_ref_equal,
+                                        (GDestroyNotify) ostree_collection_ref_free,
+                                        g_free);
+
+  summary_v = g_variant_new_from_bytes (OSTREE_SUMMARY_GVARIANT_FORMAT,
+                                        summary_bytes, FALSE);
+  additional_metadata_v = g_variant_get_child_value (summary_v, 1);
+
+  /* List the refs in the main map. */
+  if (!g_variant_lookup (additional_metadata_v, OSTREE_SUMMARY_COLLECTION_ID, "&s", &summary_collection_id))
+    summary_collection_id = NULL;
+
+  summary_refs = g_variant_get_child_value (summary_v, 0);
+
+  if (!remote_list_collection_refs_process_refs (self, remote_name,
+                                                summary_collection_id, summary_refs,
+                                                ret_all_refs, error))
+    return FALSE;
+
+  /* List the refs in the collection map. */
+  if (!g_variant_lookup (additional_metadata_v, OSTREE_SUMMARY_COLLECTION_MAP, "a{sa(s(taya{sv}))}", &summary_collection_map))
+    summary_collection_map = NULL;
+
+  while (summary_collection_map != NULL &&
+         g_variant_iter_loop (summary_collection_map, "{s@a(s(taya{sv}))}", &summary_collection_id, &summary_refs))
+    {
+      if (!remote_list_collection_refs_process_refs (self, remote_name,
+                                                     summary_collection_id, summary_refs,
+                                                     ret_all_refs, error))
+        return FALSE;
+    }
+
+  ot_transfer_out_value (out_all_refs, &ret_all_refs);
+  return TRUE;
+}
+#endif  /* OSTREE_ENABLE_EXPERIMENTAL_API */
+
 static char *
 relative_symlink_to (const char *relpath,
                      const char *target)

src/libostree/ostree-repo.h

@@ -482,6 +482,15 @@ gboolean ostree_repo_remote_list_refs (OstreeRepo       *self,
                                        GCancellable     *cancellable,
                                        GError          **error);
 
+#ifdef OSTREE_ENABLE_EXPERIMENTAL_API
+_OSTREE_PUBLIC
+gboolean ostree_repo_remote_list_collection_refs (OstreeRepo    *self,
+                                                  const char    *remote_name,
+                                                  GHashTable   **out_all_refs,
+                                                  GCancellable  *cancellable,
+                                                  GError       **error);
+#endif  /* OSTREE_ENABLE_EXPERIMENTAL_API */
+
 _OSTREE_PUBLIC
 gboolean      ostree_repo_load_variant (OstreeRepo  *self,
                                         OstreeObjectType objtype,