[gnome-builder] plugins/podman: use separate parser for layers

[Christian Hergert <chergert src gnome org>]

commit 7a5fe9494f6eb14d2ffdb06d12d7af09b4ae5720
Author: Christian Hergert <chergert redhat com>
Date:   Mon Apr 25 14:54:18 2022 -0700

    plugins/podman: use separate parser for layers
    
    Also fix the string lifetime issue with out finding the layer was supposed
    to work (by freeing caller to be replaced with return value). We need to
    use a separate parser for the layer because it would cause pointers to
    const strings to become invalid by clearing the old parser state.
    
    Always set g_autoptr() values to NULL.

 src/plugins/podman/gbp-podman-runtime.c | 74 ++++++++++++++++++++++-----------
 1 file changed, 49 insertions(+), 25 deletions(-)
---
diff --git a/src/plugins/podman/gbp-podman-runtime.c b/src/plugins/podman/gbp-podman-runtime.c
index eb12b4417..c61b995fe 100644
--- a/src/plugins/podman/gbp-podman-runtime.c
+++ b/src/plugins/podman/gbp-podman-runtime.c
@@ -188,7 +188,7 @@ get_layer_dir (const char *storage_directory,
 static char *
 find_parent_layer (GbpPodmanRuntime *runtime,
                    JsonParser       *parser,
-                   const char       *layer)
+                   char             *layer)
 {
   JsonNode *root;
   JsonArray *ar;
@@ -200,7 +200,10 @@ find_parent_layer (GbpPodmanRuntime *runtime,
   if (!(root = json_parser_get_root (parser)) ||
       !JSON_NODE_HOLDS_ARRAY (root) ||
       !(ar = json_node_get_array (root)))
-    return NULL;
+    {
+      g_free (layer);
+      return NULL;
+    }
 
   n_items = json_array_get_length (ar);
 
@@ -218,9 +221,13 @@ find_parent_layer (GbpPodmanRuntime *runtime,
           !(parent = json_object_get_string_member (item, "parent")))
         continue;
 
-      return (char *)parent;
+      g_free (layer);
+
+      return g_strdup (parent);
     }
 
+  g_free (layer);
+
   return NULL;
 }
 
@@ -256,7 +263,7 @@ find_image_layer (JsonParser *parser,
           !(layer = json_object_get_string_member (item, "layer")))
         continue;
 
-      return (char *)layer;
+      return g_strdup (layer);
     }
 
   return NULL;
@@ -265,26 +272,30 @@ find_image_layer (JsonParser *parser,
 static void
 resolve_overlay (GbpPodmanRuntime *runtime)
 {
-  gchar *podman_id;
-  g_autofree gchar *container_json = NULL;
-  g_autofree gchar *layer_json = NULL;
-  g_autofree gchar *image_json = NULL;
+  g_autofree char *container_json = NULL;
+  g_autofree char *layer_json = NULL;
+  g_autofree char *image_json = NULL;
   g_autofree char *storage_directory = NULL;
-  g_autoptr(JsonParser) parser;
-  g_autoptr(JsonParser) image_parser;
+  g_autoptr(JsonParser) parser = NULL;
+  g_autoptr(JsonParser) image_parser = NULL;
+  g_autoptr(JsonParser) layer_parser = NULL;
   g_autoptr(GFile) overlay = NULL;
   g_autoptr(GFileInfo) overlay_info = NULL;
   g_autoptr(GError) error = NULL;
-  const gchar *image_id = NULL;
+  const char *image_id = NULL;
+  const char *podman_id;
   JsonNode *root;
   JsonArray *containers_arr;
-  gchar *layer = NULL;
+  char *layer = NULL;
+
+  IDE_ENTRY;
 
   g_assert (GBP_IS_PODMAN_RUNTIME (runtime));
 
   podman_id = runtime->id;
   parser = json_parser_new ();
   image_parser = json_parser_new ();
+  layer_parser = json_parser_new ();
 
   /* find storage location first */
   if ((storage_directory = get_storage_directory ()) == NULL)
@@ -308,13 +319,13 @@ resolve_overlay (GbpPodmanRuntime *runtime)
   if (error)
     {
       ide_object_warning (ide_object_get_context (IDE_OBJECT (runtime)), "Cannot read overlay folder: %s", 
error->message);
-      return;
+      IDE_EXIT;
     }
 
   if (!g_file_info_get_attribute_boolean (overlay_info, G_FILE_ATTRIBUTE_ACCESS_CAN_READ))
     {
       ide_object_warning (ide_object_get_context (IDE_OBJECT (runtime)), "Cannot read overlay folder: podman 
file translation won't work");
-      return;
+      IDE_EXIT;
     }
 
   container_json = g_build_filename (storage_directory,
@@ -339,37 +350,50 @@ resolve_overlay (GbpPodmanRuntime *runtime)
     {
       JsonObject *cont = json_array_get_object_element (containers_arr, i);
       const gchar *cid = json_object_get_string_member (cont, "id");
+
       if (ide_str_equal0 (cid, podman_id))
         {
-          const gchar *layer_id = json_object_get_string_member (cont, "layer");
-          layer = get_layer_dir (storage_directory, layer_id);
+          const char *layer_id = json_object_get_string_member (cont, "layer");
+          g_autofree char *layer_dir = get_layer_dir (storage_directory, layer_id);
+
+          if (layer_dir)
+            {
+              g_clear_pointer (&layer, g_free);
+              layer = g_steal_pointer (&layer_dir);
+            }
+
           image_id = json_object_get_string_member (cont, "image");
         }
     }
 
-  json_parser_load_from_file (parser, layer_json, &error);
-  if (error)
-    return;
+  layer_parser = json_parser_new ();
+  if (!json_parser_load_from_file (layer_parser, layer_json, &error))
+    IDE_EXIT;
 
   if (layer != NULL)
     {
       /* apply all parent layers */
       do {
-        runtime->layers = g_list_append (runtime->layers, layer);
-      } while ((layer = find_parent_layer (runtime, parser, layer)));
+        runtime->layers = g_list_append (runtime->layers, g_strdup (layer));
+      } while ((layer = find_parent_layer (runtime, layer_parser, layer)));
     }
 
+  g_assert (layer == NULL);
+
   /* apply image layer */
-  json_parser_load_from_file (image_parser, image_json, &error);
-  if (error)
-    return;
+  if (!json_parser_load_from_file (image_parser, image_json, &error))
+    IDE_EXIT;
 
   if ((layer = find_image_layer (image_parser, image_id)))
     {
       do
-        runtime->layers = g_list_append (runtime->layers, layer);
+        runtime->layers = g_list_append (runtime->layers, g_strdup (layer));
       while ((layer = find_parent_layer (runtime, parser, layer)));
     }
+
+  g_assert (layer == NULL);
+
+  IDE_EXIT;
 }
 
 /*