Run Fuchsia apps without flx (flutter#4538)

assets/directory_asset_bundle.cc

@@ -23,15 +23,49 @@ namespace blink {
 bool DirectoryAssetBundle::GetAsBuffer(const std::string& asset_name,
                                        std::vector<uint8_t>* data) {
   std::string asset_path = GetPathForAsset(asset_name);
+
   if (asset_path.empty())
     return false;
+
+  if (fd_.is_valid()) {
+    fxl::UniqueFD asset_file(openat(fd_.get(), asset_path.c_str(), O_RDONLY));
+    if (!asset_file.is_valid()) {
+      FXL_LOG(ERROR) << "Could not load asset " << asset_name << " from "
+                     << asset_path;
+      return false;
+    }
+
+    constexpr size_t kBufferSize = 1 << 16;
+    size_t offset = 0;
+    ssize_t bytes_read = 0;
+    do {
+      offset += bytes_read;
+      data->resize(offset + kBufferSize);
+      bytes_read = read(asset_file.get(), &(*data)[offset], kBufferSize);
+    } while (bytes_read > 0);
+
+    if (bytes_read < 0) {
+      FXL_LOG(ERROR) << "Reading " << asset_name << " failed";
+      data->clear();
+      return false;
+    }
+
+    data->resize(offset + bytes_read);
+    return true;
+  }
+
   return files::ReadFileToVector(asset_path, data);
 }
 
 DirectoryAssetBundle::~DirectoryAssetBundle() {}
 
 DirectoryAssetBundle::DirectoryAssetBundle(std::string directory)
-    : directory_(std::move(directory)) {}
+    : directory_(std::move(directory)),
+      fd_(fxl::internal::UniqueFDTraits::InvalidValue()) {}
+
+DirectoryAssetBundle::DirectoryAssetBundle(fxl::UniqueFD fd,
+                                           std::string directory)
+    : directory_(std::move(directory)), fd_(std::move(fd)) {}
 
 std::string DirectoryAssetBundle::GetPathForAsset(
     const std::string& asset_name) {

assets/directory_asset_bundle.h

@@ -8,6 +8,7 @@
 #include <string>
 #include <vector>
 
+#include "lib/fxl/files/unique_fd.h"
 #include "lib/fxl/macros.h"
 #include "lib/fxl/memory/ref_counted.h"
 
@@ -17,6 +18,8 @@ class DirectoryAssetBundle
     : public fxl::RefCountedThreadSafe<DirectoryAssetBundle> {
  public:
   explicit DirectoryAssetBundle(std::string directory);
+  // Expects fd to be valid, otherwise the file descriptor is ignored.
+  explicit DirectoryAssetBundle(fxl::UniqueFD fd, std::string directory);
   ~DirectoryAssetBundle();
 
   bool GetAsBuffer(const std::string& asset_name, std::vector<uint8_t>* data);
@@ -25,6 +28,7 @@ class DirectoryAssetBundle
 
  private:
   const std::string directory_;
+  fxl::UniqueFD fd_;
 
   FXL_DISALLOW_COPY_AND_ASSIGN(DirectoryAssetBundle);
 };

content_handler/application_controller_impl.cc

@@ -32,9 +32,11 @@ ApplicationControllerImpl::ApplicationControllerImpl(
   }
 
   std::vector<char> bundle;
-  if (!fsl::VectorFromVmo(std::move(application->data), &bundle)) {
-    FXL_LOG(ERROR) << "Failed to receive bundle.";
-    return;
+  if (application->data) {
+    if (!fsl::VectorFromVmo(std::move(application->data), &bundle)) {
+      FXL_LOG(ERROR) << "Failed to receive bundle.";
+      return;
+    }
   }
 
   // TODO(jeffbrown): Decide what to do with command-line arguments and

content_handler/runtime_holder.cc

@@ -23,6 +23,7 @@
 #include "flutter/runtime/runtime_init.h"
 #include "lib/app/cpp/connect.h"
 #include "lib/fsl/vmo/vector.h"
+#include "lib/fxl/files/unique_fd.h"
 #include "lib/fxl/functional/make_copyable.h"
 #include "lib/fxl/logging.h"
 #include "lib/fxl/time/time_delta.h"
@@ -45,6 +46,7 @@ constexpr char kAssetChannel[] = "flutter/assets";
 constexpr char kKeyEventChannel[] = "flutter/keyevent";
 constexpr char kTextInputChannel[] = "flutter/textinput";
 constexpr char kFlutterPlatformChannel[] = "flutter/platform";
+constexpr char kFuchsiaPackageResourceDirectory[] = "pkg/data";
 
 void SetThreadName(fxl::RefPtr<fxl::TaskRunner> runner, std::string name) {
   runner->PostTask([name]() {
@@ -117,6 +119,7 @@ void RuntimeHolder::Init(
 
   context_->ConnectToEnvironmentService(view_manager_.NewRequest());
 
+  // TODO(zarah): remove bundle entirely once flx is removed.
   InitRootBundle(std::move(bundle));
 
   const uint8_t* vm_snapshot_data;
@@ -130,7 +133,7 @@ void RuntimeHolder::Init(
     default_isolate_snapshot_instr = ::kDartIsolateCoreSnapshotInstructions;
   } else {
     std::vector<uint8_t> dylib_blob;
-    if (!asset_store_->GetAsBuffer(kDylibKey, &dylib_blob)) {
+    if (!GetAssetAsBuffer(kDylibKey, &dylib_blob)) {
       FXL_LOG(ERROR) << "Failed to extract app dylib";
       return;
     }
@@ -193,8 +196,8 @@ void RuntimeHolder::CreateView(
   std::vector<uint8_t> kernel;
   std::vector<uint8_t> snapshot;
   if (!Dart_IsPrecompiledRuntime()) {
-    if (!asset_store_->GetAsBuffer(kKernelKey, &kernel) &&
-        !asset_store_->GetAsBuffer(kSnapshotKey, &snapshot)) {
+    if (!GetAssetAsBuffer(kKernelKey, &kernel) &&
+        !GetAssetAsBuffer(kSnapshotKey, &snapshot)) {
       FXL_LOG(ERROR) << "Unable to load kernel or snapshot from root bundle.";
       return;
     }
@@ -387,8 +390,11 @@ void RuntimeHolder::HandlePlatformMessage(
 }
 
 void RuntimeHolder::DidCreateMainIsolate(Dart_Isolate isolate) {
-  if (asset_store_)
+  if (directory_asset_bundle_) {
+    blink::AssetFontSelector::Install(directory_asset_bundle_);
+  } else if (asset_store_) {
     blink::AssetFontSelector::Install(asset_store_);
+  }
   InitDartIoInternal();
   InitFuchsia();
   InitMozartInternal();
@@ -448,9 +454,19 @@ void RuntimeHolder::InitMozartInternal() {
 }
 
 void RuntimeHolder::InitRootBundle(std::vector<char> bundle) {
-  root_bundle_data_ = std::move(bundle);
-  asset_store_ = fxl::MakeRefCounted<blink::ZipAssetStore>(
-      GetUnzipperProviderForRootBundle());
+  if (!bundle.empty()) {
+    root_bundle_data_ = std::move(bundle);
+    asset_store_ = fxl::MakeRefCounted<blink::ZipAssetStore>(
+        GetUnzipperProviderForRootBundle());
+  } else {
+    fxl::UniqueFD root_dir(fdio_ns_opendir(namespc_));
+    if (!root_dir.is_valid()) {
+      FXL_LOG(ERROR) << "Unable to load root dir";
+      return;
+    }
+    directory_asset_bundle_ = fxl::MakeRefCounted<blink::DirectoryAssetBundle>(
+        std::move(root_dir), kFuchsiaPackageResourceDirectory);
+  }
 }
 
 mozart::View* RuntimeHolder::GetMozartView() {
@@ -466,14 +482,21 @@ bool RuntimeHolder::HandleAssetPlatformMessage(
   std::string asset_name(reinterpret_cast<const char*>(data.data()),
                          data.size());
   std::vector<uint8_t> asset_data;
-  if (asset_store_ && asset_store_->GetAsBuffer(asset_name, &asset_data)) {
+  if (GetAssetAsBuffer(asset_name, &asset_data)) {
     response->Complete(std::move(asset_data));
   } else {
     response->CompleteEmpty();
   }
   return true;
 }
 
+bool RuntimeHolder::GetAssetAsBuffer(const std::string& name,
+                                     std::vector<uint8_t>* data) {
+  return (directory_asset_bundle_ &&
+          directory_asset_bundle_->GetAsBuffer(name, data)) ||
+         (asset_store_ && asset_store_->GetAsBuffer(name, data));
+}
+
 bool RuntimeHolder::HandleFlutterPlatformMessage(
     blink::PlatformMessage* message) {
   const auto& data = message->data();

content_handler/runtime_holder.h

@@ -11,6 +11,7 @@
 #include <unordered_set>
 
 #include "dart-pkg/fuchsia/sdk_ext/fuchsia.h"
+#include "flutter/assets/directory_asset_bundle.h"
 #include "flutter/assets/unzipper_provider.h"
 #include "flutter/assets/zip_asset_store.h"
 #include "flutter/content_handler/accessibility_bridge.h"
@@ -92,6 +93,7 @@ class RuntimeHolder : public blink::RuntimeDelegate,
   void InitRootBundle(std::vector<char> bundle);
   blink::UnzipperProvider GetUnzipperProviderForRootBundle();
   bool HandleAssetPlatformMessage(blink::PlatformMessage* message);
+  bool GetAssetAsBuffer(const std::string& name, std::vector<uint8_t>* data);
   bool HandleTextInputPlatformMessage(blink::PlatformMessage* message);
   bool HandleFlutterPlatformMessage(blink::PlatformMessage* message);
 
@@ -109,7 +111,9 @@ class RuntimeHolder : public blink::RuntimeDelegate,
   std::unique_ptr<app::ApplicationContext> context_;
   fidl::InterfaceRequest<app::ServiceProvider> outgoing_services_;
   std::vector<char> root_bundle_data_;
+  // TODO(zarah): Remove asset_store_ when flx is completely removed
   fxl::RefPtr<blink::ZipAssetStore> asset_store_;
+  fxl::RefPtr<blink::DirectoryAssetBundle> directory_asset_bundle_;
   void* dylib_handle_ = nullptr;
   std::unique_ptr<Rasterizer> rasterizer_;
   std::unique_ptr<blink::RuntimeController> runtime_;