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/Optimize.cpp b/tools/aapt2/optimize/Optimize.cpp
new file mode 100644
index 0000000..9615962
--- /dev/null
+++ b/tools/aapt2/optimize/Optimize.cpp
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) 2017 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 <memory>
+#include <vector>
+
+#include "androidfw/StringPiece.h"
+
+#include "Diagnostics.h"
+#include "Flags.h"
+#include "LoadedApk.h"
+#include "SdkConstants.h"
+#include "flatten/TableFlattener.h"
+#include "optimize/ResourceDeduper.h"
+#include "optimize/VersionCollapser.h"
+#include "split/TableSplitter.h"
+
+using android::StringPiece;
+
+namespace aapt {
+
+struct OptimizeOptions {
+  // Path to the output APK.
+  std::string output_path;
+
+  // List of screen density configurations the APK will be optimized for.
+  std::vector<ConfigDescription> target_configs;
+
+  TableFlattenerOptions table_flattener_options;
+};
+
+class OptimizeContext : public IAaptContext {
+ public:
+  IDiagnostics* GetDiagnostics() override { return &diagnostics_; }
+
+  NameMangler* GetNameMangler() override {
+    abort();
+    return nullptr;
+  }
+
+  const std::string& GetCompilationPackage() override {
+    static std::string empty;
+    return empty;
+  }
+
+  uint8_t GetPackageId() override { return 0; }
+
+  SymbolTable* GetExternalSymbols() override {
+    abort();
+    return nullptr;
+  }
+
+  bool IsVerbose() override { return verbose_; }
+
+  void SetVerbose(bool val) { verbose_ = val; }
+
+  void SetMinSdkVersion(int sdk_version) { sdk_version_ = sdk_version; }
+
+  int GetMinSdkVersion() override { return sdk_version_; }
+
+ private:
+  StdErrDiagnostics diagnostics_;
+  bool verbose_ = false;
+  int sdk_version_ = 0;
+};
+
+class OptimizeCommand {
+ public:
+  OptimizeCommand(OptimizeContext* context, const OptimizeOptions& options)
+      : options_(options),
+        context_(context) {}
+
+  int Run(std::unique_ptr<LoadedApk> apk) {
+    if (context_->IsVerbose()) {
+      context_->GetDiagnostics()->Note(DiagMessage() << "Optimizing APK...");
+    }
+
+    VersionCollapser collapser;
+    if (!collapser.Consume(context_, apk->GetResourceTable())) {
+      return 1;
+    }
+
+    ResourceDeduper deduper;
+    if (!deduper.Consume(context_, apk->GetResourceTable())) {
+      context_->GetDiagnostics()->Error(DiagMessage() << "failed deduping resources");
+      return 1;
+    }
+
+    // Stripping the APK using the TableSplitter with no splits and the target
+    // densities as the preferred densities. The resource table is modified in
+    // place in the LoadedApk.
+    TableSplitterOptions splitter_options;
+    for (auto& config : options_.target_configs) {
+      splitter_options.preferred_densities.push_back(config.density);
+    }
+    std::vector<SplitConstraints> splits;
+    TableSplitter splitter(splits, splitter_options);
+    splitter.SplitTable(apk->GetResourceTable());
+
+    std::unique_ptr<IArchiveWriter> writer =
+        CreateZipFileArchiveWriter(context_->GetDiagnostics(), options_.output_path);
+    if (!apk->WriteToArchive(context_, options_.table_flattener_options, writer.get())) {
+      return 1;
+    }
+
+    return 0;
+  }
+
+ private:
+  OptimizeOptions options_;
+  OptimizeContext* context_;
+};
+
+int Optimize(const std::vector<StringPiece>& args) {
+  OptimizeContext context;
+  OptimizeOptions options;
+  Maybe<std::string> target_densities;
+  bool verbose = false;
+  Flags flags =
+      Flags()
+          .RequiredFlag("-o", "Path to the output APK.", &options.output_path)
+          .OptionalFlag(
+              "--target-densities",
+              "Comma separated list of the screen densities that the APK will "
+              "be optimized for. All the resources that would be unused on "
+              "devices of the given densities will be removed from the APK.",
+              &target_densities)
+          .OptionalSwitch("--enable-sparse-encoding",
+                          "Enables encoding sparse entries using a binary search tree.\n"
+                          "This decreases APK size at the cost of resource retrieval performance.",
+                          &options.table_flattener_options.use_sparse_entries)
+          .OptionalSwitch("-v", "Enables verbose logging", &verbose);
+
+  if (!flags.Parse("aapt2 optimize", args, &std::cerr)) {
+    return 1;
+  }
+
+  if (flags.GetArgs().size() != 1u) {
+    std::cerr << "must have one APK as argument.\n\n";
+    flags.Usage("aapt2 optimize", &std::cerr);
+    return 1;
+  }
+
+  std::unique_ptr<LoadedApk> apk =
+      LoadedApk::LoadApkFromPath(&context, flags.GetArgs()[0]);
+  if (!apk) {
+    return 1;
+  }
+
+  if (verbose) {
+    context.SetVerbose(verbose);
+  }
+
+  if (target_densities) {
+    // Parse the target screen densities.
+    for (const StringPiece& config_str : util::Tokenize(target_densities.value(), ',')) {
+      ConfigDescription config;
+      if (!ConfigDescription::Parse(config_str, &config) || config.density == 0) {
+        context.GetDiagnostics()->Error(
+            DiagMessage() << "invalid density '" << config_str
+                          << "' for --target-densities option");
+        return 1;
+      }
+
+      // Clear the version that can be automatically added.
+      config.sdkVersion = 0;
+
+      if (config.diff(ConfigDescription::DefaultConfig()) !=
+          ConfigDescription::CONFIG_DENSITY) {
+        context.GetDiagnostics()->Error(
+            DiagMessage() << "invalid density '" << config_str
+                          << "' for --target-densities option. Must be only a "
+                          << "density value.");
+        return 1;
+      }
+
+      options.target_configs.push_back(config);
+    }
+  }
+
+  // TODO(adamlesinski): Read manfiest and set the proper minSdkVersion.
+  // context.SetMinSdkVersion(SDK_O);
+
+  OptimizeCommand cmd(&context, options);
+  return cmd.Run(std::move(apk));
+}
+
+}  // namespace aapt