AAPT2: Add <overlayable> tag support

This doesn't actually do anything yet, but makes sure
it is not a syntax error and allows teams to start marking
their resources as overlayable.

The syntax form marking a set of resources as overlayable
looks like:

  <overlayable policy="system">
    <item type="string" name="foo" />
    <item type="style" name="bar" />
  </overlayable>

Currently, the only supported policy is "system", meaning only
the system will be able to overlay the resources. Leaving
out the policy attribute defaults to "system".

Bug: 64980941
Test: make aapt2_tests
Change-Id: Ied7a9ddae87a4a0af6a0f4d1c213bfce8a0ed612

1 files changed, 45 insertions, 0 deletions

diff --git a/tools/aapt2/ResourceParser_test.cpp b/tools/aapt2/ResourceParser_test.cpp
index 144ebd22e105..f08b03e7b8af 100644
--- a/tools/aapt2/ResourceParser_test.cpp
+++ b/tools/aapt2/ResourceParser_test.cpp
@@ -790,4 +790,49 @@ TEST_F(ResourceParserTest, ParsePlatformIndependentNewline) {
   ASSERT_TRUE(TestParse(R"(<string name="foo">%1$s %n %2$s</string>)"));
 }
 
+TEST_F(ResourceParserTest, ParseOverlayableTagWithSystemPolicy) {
+  std::string input = R"(
+      <overlayable policy="illegal_policy">
+        <item type="string" name="foo" />
+      </overlayable>)";
+  EXPECT_FALSE(TestParse(input));
+
+  input = R"(
+      <overlayable policy="system">
+        <item name="foo" />
+      </overlayable>)";
+  EXPECT_FALSE(TestParse(input));
+
+  input = R"(
+      <overlayable policy="system">
+        <item type="attr" />
+      </overlayable>)";
+  EXPECT_FALSE(TestParse(input));
+
+  input = R"(
+      <overlayable policy="system">
+        <item type="bad_type" name="foo" />
+      </overlayable>)";
+  EXPECT_FALSE(TestParse(input));
+
+  input = R"(<overlayable policy="system" />)";
+  EXPECT_TRUE(TestParse(input));
+
+  input = R"(<overlayable />)";
+  EXPECT_TRUE(TestParse(input));
+
+  input = R"(
+      <overlayable policy="system">
+        <item type="string" name="foo" />
+        <item type="dimen" name="foo" />
+      </overlayable>)";
+  ASSERT_TRUE(TestParse(input));
+
+  input = R"(
+      <overlayable>
+        <item type="string" name="bar" />
+      </overlayable>)";
+  ASSERT_TRUE(TestParse(input));
+}
+
 }  // namespace aapt