Merge "AAPT2: GetBag infinite recursion fix" into pi-dev

libs/androidfw/AssetManager2.cpp

@@ -18,6 +18,7 @@
 
 #include "androidfw/AssetManager2.h"
 
+#include <algorithm>
 #include <iterator>
 #include <set>
 
@@ -567,6 +568,11 @@ ApkAssetsCookie AssetManager2::ResolveReference(ApkAssetsCookie cookie, Res_valu
 }
 
 const ResolvedBag* AssetManager2::GetBag(uint32_t resid) {
+  auto found_resids = std::vector<uint32_t>();
+  return GetBag(resid, found_resids);
+}
+
+const ResolvedBag* AssetManager2::GetBag(uint32_t resid, std::vector<uint32_t>& child_resids) {
   ATRACE_NAME("AssetManager::GetBag");
 
   auto cached_iter = cached_bags_.find(resid);
@@ -595,10 +601,15 @@ const ResolvedBag* AssetManager2::GetBag(uint32_t resid) {
       reinterpret_cast<const ResTable_map*>(reinterpret_cast<const uint8_t*>(map) + map->size);
   const ResTable_map* const map_entry_end = map_entry + dtohl(map->count);
 
+  // Keep track of ids that have already been seen to prevent infinite loops caused by circular
+  // dependencies between bags
+  child_resids.push_back(resid);
+
   uint32_t parent_resid = dtohl(map->parent.ident);
-  if (parent_resid == 0 || parent_resid == resid) {
-    // There is no parent, meaning there is nothing to inherit and we can do a simple
-    // copy of the entries in the map.
+  if (parent_resid == 0 || std::find(child_resids.begin(), child_resids.end(), parent_resid)
+      != child_resids.end()) {
+    // There is no parent or that a circular dependency exist, meaning there is nothing to
+    // inherit and we can do a simple copy of the entries in the map.
     const size_t entry_count = map_entry_end - map_entry;
     util::unique_cptr<ResolvedBag> new_bag{reinterpret_cast<ResolvedBag*>(
         malloc(sizeof(ResolvedBag) + (entry_count * sizeof(ResolvedBag::Entry))))};
@@ -639,7 +650,7 @@ const ResolvedBag* AssetManager2::GetBag(uint32_t resid) {
   entry.dynamic_ref_table->lookupResourceId(&parent_resid);
 
   // Get the parent and do a merge of the keys.
-  const ResolvedBag* parent_bag = GetBag(parent_resid);
+  const ResolvedBag* parent_bag = GetBag(parent_resid, child_resids);
   if (parent_bag == nullptr) {
     // Failed to get the parent that should exist.
     LOG(ERROR) << base::StringPrintf("Failed to find parent 0x%08x of bag 0x%08x.", parent_resid,

libs/androidfw/include/androidfw/AssetManager2.h

@@ -276,6 +276,10 @@ class AssetManager2 {
   // This should always be called when mutating the AssetManager's configuration or ApkAssets set.
   void RebuildFilterList();
 
+  // AssetManager2::GetBag(resid) wraps this function to track which resource ids have already
+  // been seen while traversing bag parents.
+  const ResolvedBag* GetBag(uint32_t resid, std::vector<uint32_t>& child_resids);
+
   // The ordered list of ApkAssets to search. These are not owned by the AssetManager, and must
   // have a longer lifetime.
   std::vector<const ApkAssets*> apk_assets_;

libs/androidfw/tests/AssetManager2_test.cpp

@@ -329,6 +329,17 @@ TEST_F(AssetManager2Test, MergesStylesWithParentFromSingleApkAssets) {
   EXPECT_EQ(0, bag_two->entries[5].cookie);
 }
 
+TEST_F(AssetManager2Test, MergeStylesCircularDependency) {
+  AssetManager2 assetmanager;
+  assetmanager.SetApkAssets({style_assets_.get()});
+
+  // GetBag should stop traversing the parents of styles when a circular
+  // dependency is detected
+  const ResolvedBag* bag_one = assetmanager.GetBag(app::R::style::StyleFour);
+  ASSERT_NE(nullptr, bag_one);
+  ASSERT_EQ(3u, bag_one->entry_count);
+}
+
 TEST_F(AssetManager2Test, ResolveReferenceToResource) {
   AssetManager2 assetmanager;
   assetmanager.SetApkAssets({basic_assets_.get()});

libs/androidfw/tests/data/styles/R.h

@@ -48,6 +48,9 @@ struct R {
       StyleOne = 0x7f020000u,
       StyleTwo = 0x7f020001u,
       StyleThree = 0x7f020002u,
+      StyleFour = 0x7f020003u,
+      StyleFive = 0x7f020004u,
+      StyleSix = 0x7f020005u,
     };
   };
 };

libs/androidfw/tests/data/styles/res/values/styles.xml

@@ -63,4 +63,20 @@
         <item name="attr_five">5</item>
     </style>
 
+    <!-- Circular parental dependency -->
+    <public type="style" name="StyleFour" id="0x7f020003" />
+    <style name="StyleFour" parent="StyleFive">
+        <item name="attr_one">1</item>
+    </style>
+
+    <public type="style" name="StyleFive" id="0x7f020004" />
+    <style name="StyleFive" parent="StyleSix">
+        <item name="attr_two">2</item>
+    </style>
+
+    <public type="style" name="StyleSix" id="0x7f020005" />
+    <style name="StyleSix" parent="StyleFour">
+        <item name="attr_three">3</item>
+    </style>
+
 </resources>