AAPT2: Rename strip phase to optimize
- Allow resource deduping, version collapsing, and sparse resource
encoding.
Test: manual
Change-Id: Ia4aa892ab5b06ba1d5ea4a6efb51b00bc3a980c4
diff --git a/tools/aapt2/optimize/VersionCollapser.cpp b/tools/aapt2/optimize/VersionCollapser.cpp
new file mode 100644
index 0000000..d941b48
--- /dev/null
+++ b/tools/aapt2/optimize/VersionCollapser.cpp
@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2016 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/VersionCollapser.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "ResourceTable.h"
+
+namespace aapt {
+
+template <typename Iterator, typename Pred>
+class FilterIterator {
+ public:
+ FilterIterator(Iterator begin, Iterator end, Pred pred = Pred())
+ : current_(begin), end_(end), pred_(pred) {
+ Advance();
+ }
+
+ bool HasNext() { return current_ != end_; }
+
+ Iterator NextIter() {
+ Iterator iter = current_;
+ ++current_;
+ Advance();
+ return iter;
+ }
+
+ typename Iterator::reference Next() { return *NextIter(); }
+
+ private:
+ void Advance() {
+ for (; current_ != end_; ++current_) {
+ if (pred_(*current_)) {
+ return;
+ }
+ }
+ }
+
+ Iterator current_, end_;
+ Pred pred_;
+};
+
+template <typename Iterator, typename Pred>
+FilterIterator<Iterator, Pred> make_filter_iterator(Iterator begin,
+ Iterator end = Iterator(),
+ Pred pred = Pred()) {
+ return FilterIterator<Iterator, Pred>(begin, end, pred);
+}
+
+/**
+ * Every Configuration with an SDK version specified that is less than minSdk
+ * will be removed.
+ * The exception is when there is no exact matching resource for the minSdk. The
+ * next smallest
+ * one will be kept.
+ */
+static void CollapseVersions(int min_sdk, ResourceEntry* entry) {
+ // First look for all sdks less than minSdk.
+ for (auto iter = entry->values.rbegin(); iter != entry->values.rend();
+ ++iter) {
+ // Check if the item was already marked for removal.
+ if (!(*iter)) {
+ continue;
+ }
+
+ const ConfigDescription& config = (*iter)->config;
+ if (config.sdkVersion <= min_sdk) {
+ // This is the first configuration we've found with a smaller or equal SDK
+ // level
+ // to the minimum. We MUST keep this one, but remove all others we find,
+ // which get
+ // overridden by this one.
+
+ ConfigDescription config_without_sdk = config.CopyWithoutSdkVersion();
+ auto pred = [&](const std::unique_ptr<ResourceConfigValue>& val) -> bool {
+ // Check that the value hasn't already been marked for removal.
+ if (!val) {
+ return false;
+ }
+
+ // Only return Configs that differ in SDK version.
+ config_without_sdk.sdkVersion = val->config.sdkVersion;
+ return config_without_sdk == val->config &&
+ val->config.sdkVersion <= min_sdk;
+ };
+
+ // Remove the rest that match.
+ auto filter_iter =
+ make_filter_iterator(iter + 1, entry->values.rend(), pred);
+ while (filter_iter.HasNext()) {
+ filter_iter.Next() = {};
+ }
+ }
+ }
+
+ // Now erase the nullptr values.
+ entry->values.erase(
+ std::remove_if(entry->values.begin(), entry->values.end(),
+ [](const std::unique_ptr<ResourceConfigValue>& val)
+ -> bool { return val == nullptr; }),
+ entry->values.end());
+
+ // Strip the version qualifiers for every resource with version <= minSdk.
+ // This will ensure
+ // that the resource entries are all packed together in the same ResTable_type
+ // struct
+ // and take up less space in the resources.arsc table.
+ bool modified = false;
+ for (std::unique_ptr<ResourceConfigValue>& config_value : entry->values) {
+ if (config_value->config.sdkVersion != 0 &&
+ config_value->config.sdkVersion <= min_sdk) {
+ // Override the resource with a Configuration without an SDK.
+ std::unique_ptr<ResourceConfigValue> new_value =
+ util::make_unique<ResourceConfigValue>(
+ config_value->config.CopyWithoutSdkVersion(),
+ config_value->product);
+ new_value->value = std::move(config_value->value);
+ config_value = std::move(new_value);
+
+ modified = true;
+ }
+ }
+
+ if (modified) {
+ // We've modified the keys (ConfigDescription) by changing the sdkVersion to
+ // 0. We MUST re-sort to ensure ordering guarantees hold.
+ std::sort(entry->values.begin(), entry->values.end(),
+ [](const std::unique_ptr<ResourceConfigValue>& a,
+ const std::unique_ptr<ResourceConfigValue>& b) -> bool {
+ return a->config.compare(b->config) < 0;
+ });
+ }
+}
+
+bool VersionCollapser::Consume(IAaptContext* context, ResourceTable* table) {
+ const int min_sdk = context->GetMinSdkVersion();
+ for (auto& package : table->packages) {
+ for (auto& type : package->types) {
+ for (auto& entry : type->entries) {
+ CollapseVersions(min_sdk, entry.get());
+ }
+ }
+ }
+ return true;
+}
+
+} // namespace aapt
