Aapt2 Optimize: Exempt particular resources from path shortening

Design: go/no_path_shorten
Bug: b/246845175
Test: Added new atests and verified affected atests pass
Change-Id: I4d5b48ea9f0efd4740823101b9a3d776d151a808
diff --git a/tools/aapt2/optimize/Obfuscator.cpp b/tools/aapt2/optimize/Obfuscator.cpp
index cc21093..8f12f735 100644
--- a/tools/aapt2/optimize/Obfuscator.cpp
+++ b/tools/aapt2/optimize/Obfuscator.cpp
@@ -83,13 +83,18 @@
 };
 
 static bool HandleShortenFilePaths(ResourceTable* table,
-                                   std::map<std::string, std::string>& shortened_path_map) {
+                                   std::map<std::string, std::string>& shortened_path_map,
+                                   const std::set<ResourceName>& path_shorten_exemptions) {
   // used to detect collisions
   std::unordered_set<std::string> shortened_paths;
   std::set<FileReference*, PathComparator> file_refs;
   for (auto& package : table->packages) {
     for (auto& type : package->types) {
       for (auto& entry : type->entries) {
+        ResourceName resource_name({}, type->named_type, entry->name);
+        if (path_shorten_exemptions.find(resource_name) != path_shorten_exemptions.end()) {
+          continue;
+        }
         for (auto& config_value : entry->values) {
           FileReference* file_ref = ValueCast<FileReference>(config_value->value.get());
           if (file_ref) {
@@ -188,7 +193,8 @@
   HandleCollapseKeyStringPool(table, options_.collapse_key_stringpool,
                               options_.name_collapse_exemptions, options_.id_resource_map);
   if (shorten_resource_paths_) {
-    return HandleShortenFilePaths(table, options_.shortened_path_map);
+    return HandleShortenFilePaths(table, options_.shortened_path_map,
+                                  options_.path_shorten_exemptions);
   }
   return true;
 }
diff --git a/tools/aapt2/optimize/Obfuscator_test.cpp b/tools/aapt2/optimize/Obfuscator_test.cpp
index 7f57b71..940cf10 100644
--- a/tools/aapt2/optimize/Obfuscator_test.cpp
+++ b/tools/aapt2/optimize/Obfuscator_test.cpp
@@ -28,6 +28,7 @@
 using ::testing::AnyOf;
 using ::testing::Eq;
 using ::testing::HasSubstr;
+using ::testing::IsFalse;
 using ::testing::IsTrue;
 using ::testing::Not;
 using ::testing::NotNull;
@@ -102,6 +103,44 @@
   ASSERT_THAT(path_map.find("res/color-mdp-v21/colorlist.xml"), Eq(path_map.end()));
 }
 
+TEST(ObfuscatorTest, SkipPathShortenExemptions) {
+  std::unique_ptr<IAaptContext> context = test::ContextBuilder().Build();
+
+  std::unique_ptr<ResourceTable> table =
+      test::ResourceTableBuilder()
+          .AddFileReference("android:drawable/xmlfile", "res/drawables/xmlfile.xml")
+          .AddFileReference("android:drawable/xmlfile2", "res/drawables/xmlfile2.xml")
+          .AddString("android:string/string", "res/should/still/be/the/same.png")
+          .Build();
+
+  OptimizeOptions options{.shorten_resource_paths = true};
+  TableFlattenerOptions& flattenerOptions = options.table_flattener_options;
+  flattenerOptions.path_shorten_exemptions.insert(
+      ResourceName({}, ResourceType::kDrawable, "xmlfile"));
+  std::map<std::string, std::string>& path_map = options.table_flattener_options.shortened_path_map;
+  ASSERT_TRUE(Obfuscator(options).Consume(context.get(), table.get()));
+
+  // Expect that the path map to not contain the first drawable which is in exemption set
+  EXPECT_THAT(path_map.find("res/drawables/xmlfile.xml"), Eq(path_map.end()));
+
+  // Expect that the path map to contain the second drawable which is not in exemption set
+  EXPECT_THAT(path_map.find("res/drawables/xmlfile2.xml"), Not(Eq(path_map.end())));
+
+  FileReference* ref = GetValue<FileReference>(table.get(), "android:drawable/xmlfile");
+  EXPECT_THAT(ref, NotNull());
+  ASSERT_THAT(HasFailure(), IsFalse());
+  // The path of first drawable in exemption was not changed
+  EXPECT_THAT("res/drawables/xmlfile.xml", Eq(*ref->path));
+
+  // The file path of second drawable not in exemption set was changed
+  EXPECT_THAT(path_map.at("res/drawables/xmlfile2.xml"), Not(Eq("res/drawables/xmlfile2.xml")));
+
+  FileReference* ref2 = GetValue<FileReference>(table.get(), "android:drawable/xmlfile2");
+  ASSERT_THAT(ref, NotNull());
+  // The map of second drawable not in exemption correctly points to the new location of the file
+  EXPECT_THAT(path_map["res/drawables/xmlfile2.xml"], Eq(*ref2->path));
+}
+
 TEST(ObfuscatorTest, KeepExtensions) {
   std::unique_ptr<IAaptContext> context = test::ContextBuilder().Build();