Avoid parsing non-binary XML resource files

Summary:
Helper methods associated with resources assume that all XML files found in the APK will be the binary XML format as used by aapt.

This is not the case for "raw" XML files as pointed out in facebook#300 which could be a stand-alone XML file that the app parses manually at runtime. This crashes the resources parsing code here.

A "raw" XML file won't contain any resource references (thus making it uninteresting for many of the `RedexResources.cpp` helper methods), and we'll consider any class name in such a file out of scope for the renamer.

Reviewed By: justinjhendrick

Differential Revision: D7188390

fbshipit-source-id: 46b8c4645e5ccc39d4076b7938ac139c4acd2a5c

libredex/RedexResources.h

@@ -48,6 +48,10 @@ std::unordered_set<std::string> get_xml_files(
     const std::string& directory);
 std::unordered_set<uint32_t> get_xml_reference_attributes(
     const std::string& filename);
+// Checks if the file is in a res/raw folder. Such a file won't be considered
+// for resource remapping, class name extraction, etc. These files don't follow
+// binary XML format, and thus are out of scope for many optimizations.
+bool is_raw_resource(const std::string& filename);
 int inline_xml_reference_attributes(
     const std::string& filename,
     const std::map<uint32_t, android::Res_value>& id_to_inline_value);

libresource/RedexResources.cpp

@@ -586,8 +586,17 @@ void ensure_file_contents(
   }
 }
 
+bool is_raw_resource(const std::string& filename) {
+  return filename.find("/res/raw/") != std::string::npos
+    || filename.find("/res/raw-") != std::string::npos;
+}
+
 std::unordered_set<uint32_t> get_xml_reference_attributes(
     const std::string& filename) {
+  if (is_raw_resource(filename)) {
+    std::unordered_set<uint32_t> empty;
+    return empty;
+  }
   std::string file_contents = read_entire_file(filename);
   ensure_file_contents(file_contents, filename);
   return extract_xml_reference_attributes(file_contents, filename);
@@ -673,6 +682,9 @@ int inline_xml_reference_attributes(
 void remap_xml_reference_attributes(
     const std::string& filename,
     const std::map<uint32_t, uint32_t>& kept_to_remapped_ids) {
+  if (is_raw_resource(filename)) {
+    return;
+  }
   std::string file_contents = read_entire_file(filename);
   ensure_file_contents(file_contents, filename);
   bool made_change = false;

opt/renameclasses/RenameClassesV2.cpp

@@ -913,6 +913,9 @@ void RenameClassesPassV2::rename_classes_in_layouts(
   size_t num_layout_renamed = 0;
   auto xml_files = get_xml_files(m_apk_dir + "/res");
   for (const auto& path : xml_files) {
+    if (is_raw_resource(path)) {
+      continue;
+    }
     size_t num_renamed;
     ssize_t out_delta;
     TRACE(RENAME, 5, "Begin rename Views in layout %s\n", path.c_str());