From 3d8ca04565862c1e1e6845b9e55b59e64a68be84 Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Thu, 7 May 2020 13:13:25 +0200
Subject: [PATCH] oci: Add helpers to parse OCI delta index and manifest

---
 common/flatpak-json-oci-private.h | 11 +++++++
 common/flatpak-json-oci.c         | 55 +++++++++++++++++++++++++++++++
 2 files changed, 66 insertions(+)

diff --git a/common/flatpak-json-oci-private.h b/common/flatpak-json-oci-private.h
index f20e88e3..edb22eeb 100644
--- a/common/flatpak-json-oci-private.h
+++ b/common/flatpak-json-oci-private.h
@@ -135,6 +135,12 @@ const char *        flatpak_oci_manifest_get_layer_digest (FlatpakOciManifest *s
                                                            int                 i);
 GHashTable *        flatpak_oci_manifest_get_annotations (FlatpakOciManifest *self);
 
+/* Only useful for delta manifest */
+FlatpakOciDescriptor *flatpak_oci_manifest_find_delta_for (FlatpakOciManifest *deltamanifest,
+                                                           const char         *from_diffid,
+                                                           const char         *to_diffid);
+
+
 #define FLATPAK_TYPE_OCI_INDEX flatpak_oci_index_get_type ()
 G_DECLARE_FINAL_TYPE (FlatpakOciIndex, flatpak_oci_index, FLATPAK, OCI_INDEX, FlatpakOciVersioned)
 
@@ -162,6 +168,11 @@ FlatpakOciManifestDescriptor *flatpak_oci_index_get_manifest (FlatpakOciIndex *s
 FlatpakOciManifestDescriptor *flatpak_oci_index_get_only_manifest (FlatpakOciIndex *self);
 int                           flatpak_oci_index_get_n_manifests (FlatpakOciIndex *self);
 
+/* Only useful for delta index */
+FlatpakOciDescriptor *flatpak_oci_index_find_delta_for (FlatpakOciIndex *delta_index,
+                                                        const char      *for_digest);
+
+
 #define FLATPAK_TYPE_OCI_IMAGE flatpak_oci_image_get_type ()
 G_DECLARE_FINAL_TYPE (FlatpakOciImage, flatpak_oci_image, FLATPAK, OCI_IMAGE, FlatpakJson)
 
diff --git a/common/flatpak-json-oci.c b/common/flatpak-json-oci.c
index 95c0acff..840f0cd4 100644
--- a/common/flatpak-json-oci.c
+++ b/common/flatpak-json-oci.c
@@ -375,6 +375,36 @@ flatpak_oci_manifest_get_annotations (FlatpakOciManifest *self)
   return self->annotations;
 }
 
+FlatpakOciDescriptor *
+flatpak_oci_manifest_find_delta_for (FlatpakOciManifest *delta_manifest,
+                                     const char         *from_diffid,
+                                     const char         *to_diffid)
+{
+  int i;
+
+  if (from_diffid == NULL || to_diffid == NULL)
+    return NULL;
+
+  for (i = 0; delta_manifest->layers != NULL && delta_manifest->layers[i] != NULL; i++)
+    {
+      FlatpakOciDescriptor *layer = delta_manifest->layers[i];
+      const char *layer_from = NULL, *layer_to = NULL;
+
+      if (layer->annotations != NULL)
+        {
+          layer_from = g_hash_table_lookup (layer->annotations, "io.github.containers.delta.from");
+          layer_to = g_hash_table_lookup (layer->annotations, "io.github.containers.delta.to");
+
+          if (g_strcmp0 (layer_from, from_diffid) == 0 &&
+              g_strcmp0 (layer_to, to_diffid) == 0)
+            return layer;
+        }
+    }
+
+  return NULL;
+}
+
+
 G_DEFINE_TYPE (FlatpakOciIndex, flatpak_oci_index, FLATPAK_TYPE_OCI_VERSIONED);
 
 static void
@@ -560,6 +590,31 @@ flatpak_oci_index_remove_manifest (FlatpakOciIndex *self,
   return TRUE;
 }
 
+FlatpakOciDescriptor *
+flatpak_oci_index_find_delta_for (FlatpakOciIndex *delta_index,
+                                  const char      *for_digest)
+{
+  int i;
+
+  if (delta_index->manifests == NULL)
+    return NULL;
+
+  for (i = 0; delta_index->manifests[i] != NULL; i++)
+    {
+      FlatpakOciManifestDescriptor *d = delta_index->manifests[i];
+      const char *target;
+
+      if (d->parent.annotations == NULL)
+        continue;
+
+      target = g_hash_table_lookup (d->parent.annotations, "io.github.containers.delta.target");
+      if (g_strcmp0 (target, for_digest) == 0)
+        return &d->parent;
+    }
+
+  return NULL;
+}
+
 G_DEFINE_TYPE (FlatpakOciImage, flatpak_oci_image, FLATPAK_TYPE_JSON);
 
 static void