Merge "IsFabricatedOverlay() optimization"

libs/androidfw/ApkAssets.cpp

@@ -83,15 +83,16 @@ std::unique_ptr<ApkAssets> ApkAssets::LoadOverlay(const std::string& idmap_path,
     return {};
   }
 
+  std::string overlay_path(loaded_idmap->OverlayApkPath());
+  auto fd = unique_fd(::open(overlay_path.c_str(), O_RDONLY|O_CLOEXEC));
   std::unique_ptr<AssetsProvider> overlay_assets;
-  const std::string overlay_path(loaded_idmap->OverlayApkPath());
-  if (IsFabricatedOverlay(overlay_path)) {
+  if (IsFabricatedOverlay(fd)) {
     // Fabricated overlays do not contain resource definitions. All of the overlay resource values
     // are defined inline in the idmap.
-    overlay_assets = EmptyAssetsProvider::Create(overlay_path);
+    overlay_assets = EmptyAssetsProvider::Create(std::move(overlay_path));
   } else {
     // The overlay should be an APK.
-    overlay_assets = ZipAssetsProvider::Create(overlay_path, flags);
+    overlay_assets = ZipAssetsProvider::Create(std::move(fd), std::move(overlay_path), flags);
   }
   if (overlay_assets == nullptr) {
     return {};

libs/androidfw/AssetsProvider.cpp

@@ -393,8 +393,8 @@ std::unique_ptr<AssetsProvider> EmptyAssetsProvider::Create() {
   return std::unique_ptr<EmptyAssetsProvider>(new EmptyAssetsProvider({}));
 }
 
-std::unique_ptr<AssetsProvider> EmptyAssetsProvider::Create(const std::string& path) {
-  return std::unique_ptr<EmptyAssetsProvider>(new EmptyAssetsProvider(path));
+std::unique_ptr<AssetsProvider> EmptyAssetsProvider::Create(std::string path) {
+  return std::unique_ptr<EmptyAssetsProvider>(new EmptyAssetsProvider(std::move(path)));
 }
 
 std::unique_ptr<Asset> EmptyAssetsProvider::OpenInternal(const std::string& /* path */,

libs/androidfw/ResourceTypes.cpp

@@ -33,7 +33,9 @@
 #include <type_traits>
 #include <vector>
 
+#include <android-base/file.h>
 #include <android-base/macros.h>
+#include <android-base/utf8.h>
 #include <androidfw/ByteBucketArray.h>
 #include <androidfw/ResourceTypes.h>
 #include <androidfw/TypeWrappers.h>
@@ -236,12 +238,23 @@ void Res_png_9patch::serialize(const Res_png_9patch& patch, const int32_t* xDivs
 }
 
 bool IsFabricatedOverlay(const std::string& path) {
-  std::ifstream fin(path);
-  uint32_t magic;
-  if (fin.read(reinterpret_cast<char*>(&magic), sizeof(uint32_t))) {
-    return magic == kFabricatedOverlayMagic;
+  return IsFabricatedOverlay(path.c_str());
+}
+
+bool IsFabricatedOverlay(const char* path) {
+  auto fd = base::unique_fd(base::utf8::open(path, O_RDONLY|O_CLOEXEC));
+  if (fd < 0) {
+    return false;
   }
-  return false;
+  return IsFabricatedOverlay(fd);
+}
+
+bool IsFabricatedOverlay(base::borrowed_fd fd) {
+  uint32_t magic;
+  if (!base::ReadFullyAtOffset(fd, &magic, sizeof(magic), 0)) {
+    return false;
+  }
+  return magic == kFabricatedOverlayMagic;
 }
 
 static bool assertIdmapHeader(const void* idmap, size_t size) {

libs/androidfw/include/androidfw/AssetsProvider.h

@@ -181,7 +181,7 @@ struct MultiAssetsProvider : public AssetsProvider {
 // Does not provide any assets.
 struct EmptyAssetsProvider : public AssetsProvider {
   static std::unique_ptr<AssetsProvider> Create();
-  static std::unique_ptr<AssetsProvider> Create(const std::string& path);
+  static std::unique_ptr<AssetsProvider> Create(std::string path);
 
   bool ForEachFile(const std::string& path,
                    const std::function<void(StringPiece, FileType)>& f) const override;

libs/androidfw/include/androidfw/ResourceTypes.h

@@ -21,6 +21,7 @@
 #define _LIBS_UTILS_RESOURCE_TYPES_H
 
 #include <android-base/expected.h>
+#include <android-base/unique_fd.h>
 
 #include <androidfw/Asset.h>
 #include <androidfw/Errors.h>
@@ -58,6 +59,8 @@ constexpr const uint32_t kFabricatedOverlayCurrentVersion = 3;
 
 // Returns whether or not the path represents a fabricated overlay.
 bool IsFabricatedOverlay(const std::string& path);
+bool IsFabricatedOverlay(const char* path);
+bool IsFabricatedOverlay(android::base::borrowed_fd fd);
 
 /**
  * In C++11, char16_t is defined as *at least* 16 bits. We do a lot of