AAPT2: Add version collapsing

When an app specifies (or imports) resources with various
configurations for different SDK versions, specifying
a minSdk will make many of those resources unreachable.

Version collapsing will prune out the resources specified
for SDK versions less than the minSdk.

If, however, there is no exact matching resource for the
minSdk version, the next smallest SDK version is kept.

Change-Id: Ic7bcab6c59d65c97c67c8767358abb57cdec60a4

1 files changed, 16 insertions, 0 deletions

diff --git a/tools/aapt2/ResourceUtils.cpp b/tools/aapt2/ResourceUtils.cpp
index a0a7efc46476..302c04fc3780 100644
--- a/tools/aapt2/ResourceUtils.cpp
+++ b/tools/aapt2/ResourceUtils.cpp
@@ -16,6 +16,7 @@
 
 #include "NameMangler.h"
 #include "ResourceUtils.h"
+#include "SdkConstants.h"
 #include "flatten/ResourceTypeExtensions.h"
 #include "util/Files.h"
 #include "util/Util.h"
@@ -402,6 +403,21 @@ bool tryParseBool(const StringPiece16& str, bool* outValue) {
     return false;
 }
 
+Maybe<int> tryParseSdkVersion(const StringPiece16& str) {
+    StringPiece16 trimmedStr(util::trimWhitespace(str));
+    android::Res_value value;
+    if (android::ResTable::stringToInt(trimmedStr.data(), trimmedStr.size(), &value)) {
+        return static_cast<int>(value.data);
+    }
+
+    // Try parsing the code name.
+    std::pair<StringPiece16, int> entry = getDevelopmentSdkCodeNameAndVersion();
+    if (entry.first == trimmedStr) {
+        return entry.second;
+    }
+    return {};
+}
+
 std::unique_ptr<BinaryPrimitive> tryParseBool(const StringPiece16& str) {
     bool result = false;
     if (tryParseBool(str, &result)) {