deltas: Add ostree_repo_list_static_delta_indexes() function

This lists all the available delta indexes.

Makefile-libostree.am

@@ -184,9 +184,9 @@ libostree_1_la_SOURCES += \
 endif # USE_GPGME
 
 symbol_files = $(top_srcdir)/src/libostree/libostree-released.sym
-#if BUILDOPT_IS_DEVEL_BUILD
-#symbol_files += $(top_srcdir)/src/libostree/libostree-devel.sym
-#endif
+if BUILDOPT_IS_DEVEL_BUILD
+symbol_files += $(top_srcdir)/src/libostree/libostree-devel.sym
+endif
 # http://blog.jgc.org/2007/06/escaping-comma-and-space-in-gnu-make.html
 wl_versionscript_arg = -Wl,--version-script=
 EXTRA_DIST += \

apidoc/ostree-sections.txt

@@ -412,6 +412,7 @@ OSTREE_REPO_LIST_OBJECTS_VARIANT_TYPE
 ostree_repo_list_objects
 ostree_repo_list_commit_objects_starting_with
 ostree_repo_list_static_delta_names
+ostree_repo_list_static_delta_indexes
 OstreeStaticDeltaGenerateOpt
 ostree_repo_static_delta_generate
 ostree_repo_static_delta_execute_offline_with_signature

src/libostree/libostree-devel.sym

@@ -17,9 +17,10 @@
   Boston, MA 02111-1307, USA.
 ***/
 
-/* Copy the bits below and uncomment the include in Makefile-libostree.am
-   when adding a symbol.
-*/
+LIBOSTREE_2020.8 {
+global:
+  ostree_repo_list_static_delta_indexes;
+} LIBOSTREE_2020.7;
 
 /* Stub section for the stable release *after* this development one; don't
  * edit this other than to update the year.  This is just a copy/paste

src/libostree/ostree-repo-static-delta-core.c

@@ -168,6 +168,93 @@ ostree_repo_list_static_delta_names (OstreeRepo                  *self,
   return TRUE;
 }
 
+/**
+ * ostree_repo_list_static_delta_indexes:
+ * @self: Repo
+ * @out_indexes: (out) (element-type utf8) (transfer container): String name of delta indexes (checksum)
+ * @cancellable: Cancellable
+ * @error: Error
+ *
+ * This function synchronously enumerates all static delta indexes in the
+ * repository, returning its result in @out_indexes.
+ *
+ * Since: 2020.7
+ */
+gboolean
+ostree_repo_list_static_delta_indexes (OstreeRepo                  *self,
+                                       GPtrArray                  **out_indexes,
+                                       GCancellable                *cancellable,
+                                       GError                     **error)
+{
+  g_autoptr(GPtrArray) ret_indexes = g_ptr_array_new_with_free_func (g_free);
+
+  g_auto(GLnxDirFdIterator) dfd_iter = { 0, };
+  gboolean exists;
+  if (!ot_dfd_iter_init_allow_noent (self->repo_dir_fd, "delta-indexes", &dfd_iter,
+                                     &exists, error))
+    return FALSE;
+  if (!exists)
+    {
+      /* Note early return */
+      ot_transfer_out_value (out_indexes, &ret_indexes);
+      return TRUE;
+    }
+
+  while (TRUE)
+    {
+      g_auto(GLnxDirFdIterator) sub_dfd_iter = { 0, };
+      struct dirent *dent;
+
+      if (!glnx_dirfd_iterator_next_dent_ensure_dtype (&dfd_iter, &dent, cancellable, error))
+        return FALSE;
+      if (dent == NULL)
+        break;
+      if (dent->d_type != DT_DIR)
+        continue;
+      if (strlen (dent->d_name) != 2)
+        continue;
+
+      if (!glnx_dirfd_iterator_init_at (dfd_iter.fd, dent->d_name, FALSE,
+                                        &sub_dfd_iter, error))
+        return FALSE;
+
+      while (TRUE)
+        {
+          struct dirent *sub_dent;
+
+          if (!glnx_dirfd_iterator_next_dent_ensure_dtype (&sub_dfd_iter, &sub_dent,
+                                                           cancellable, error))
+            return FALSE;
+          if (sub_dent == NULL)
+            break;
+          if (sub_dent->d_type != DT_REG)
+            continue;
+
+          const char *name1 = dent->d_name;
+          const char *name2 = sub_dent->d_name;
+
+          /* base64 len is 43, but 2 chars are in the parent dir name */
+          if (strlen (name2) != 41 + strlen(".index") ||
+              !g_str_has_suffix (name2, ".index"))
+            continue;
+
+          g_autoptr(GString) out = g_string_new (name1);
+          g_string_append_len (out, name2, 41);
+
+          char checksum[OSTREE_SHA256_STRING_LEN+1];
+          guchar csum[OSTREE_SHA256_DIGEST_LEN];
+
+          ostree_checksum_b64_inplace_to_bytes (out->str, csum);
+          ostree_checksum_inplace_from_bytes (csum, checksum);
+
+          g_ptr_array_add (ret_indexes, g_strdup (checksum));
+        }
+    }
+
+  ot_transfer_out_value (out_indexes, &ret_indexes);
+  return TRUE;
+}
+
 gboolean
 _ostree_repo_static_delta_part_have_all_objects (OstreeRepo             *repo,
                                                  GVariant               *checksum_array,

src/libostree/ostree-repo.h

@@ -1046,6 +1046,12 @@ gboolean ostree_repo_list_static_delta_names (OstreeRepo                  *self,
                                               GCancellable                *cancellable,
                                               GError                     **error);
 
+_OSTREE_PUBLIC
+gboolean ostree_repo_list_static_delta_indexes (OstreeRepo                  *self,
+                                                GPtrArray                  **out_indexes,
+                                                GCancellable                *cancellable,
+                                                GError                     **error);
+
 /**
  * OstreeStaticDeltaGenerateOpt:
  * @OSTREE_STATIC_DELTA_GENERATE_OPT_LOWLATENCY: Optimize for speed of delta creation over space