Resource Path Obfuscation

This CL allows aapt2 to obfuscate resource paths within the output apk
and move resources to shorter obfuscated paths. This reduces apk size
when there is a large number of resources since the path metadata exists
in 4 places in the apk.

This CL adds two arguments to aapt2, one to enable resource path
obfuscation and one to point to a path to output the path map to (for
later debugging).

Test: make aapt2_tests
Bug: b/75965637

Change-Id: I9cacafe1d17800d673566b2d61b0b88f3fb8d60c

1 files changed, 67 insertions, 0 deletions

diff --git a/tools/aapt2/optimize/ResourcePathShortener_test.cpp b/tools/aapt2/optimize/ResourcePathShortener_test.cpp
new file mode 100644
index 000000000000..88cadc76c336
--- /dev/null
+++ b/tools/aapt2/optimize/ResourcePathShortener_test.cpp
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2018 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "optimize/ResourcePathShortener.h"
+
+#include "ResourceTable.h"
+#include "test/Test.h"
+
+using ::aapt::test::GetValue;
+using ::testing::Not;
+using ::testing::NotNull;
+using ::testing::Eq;
+
+namespace aapt {
+
+TEST(ResourcePathShortenerTest, FileRefPathsChangedInResourceTable) {
+  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();
+
+  std::map<std::string, std::string> path_map;
+  ASSERT_TRUE(ResourcePathShortener(path_map).Consume(context.get(), table.get()));
+
+  // Expect that the path map is populated
+  ASSERT_THAT(path_map.find("res/drawables/xmlfile.xml"), Not(Eq(path_map.end())));
+  ASSERT_THAT(path_map.find("res/drawables/xmlfile2.xml"), Not(Eq(path_map.end())));
+
+  // The file paths were changed
+  EXPECT_THAT(path_map.at("res/drawables/xmlfile.xml"), Not(Eq("res/drawables/xmlfile.xml")));
+  EXPECT_THAT(path_map.at("res/drawables/xmlfile2.xml"), Not(Eq("res/drawables/xmlfile2.xml")));
+
+  // Different file paths should remain different
+  EXPECT_THAT(path_map["res/drawables/xmlfile.xml"],
+              Not(Eq(path_map["res/drawables/xmlfile2.xml"])));
+
+  FileReference* ref =
+      GetValue<FileReference>(table.get(), "android:drawable/xmlfile");
+  ASSERT_THAT(ref, NotNull());
+  // The map correctly points to the new location of the file
+  EXPECT_THAT(path_map["res/drawables/xmlfile.xml"], Eq(*ref->path));
+
+  // Strings should not be affected, only file paths
+  EXPECT_THAT(
+      *GetValue<String>(table.get(), "android:string/string")->value,
+              Eq("res/should/still/be/the/same.png"));
+  EXPECT_THAT(path_map.find("res/should/still/be/the/same.png"), Eq(path_map.end()));
+}
+
+}   // namespace aapt