[NativeFS] Create IDL to retrieve a NativeFileSystemHandle from a DataTransferItem

In order to integrate Drag & Drop with NativeFileSystem,
 we need to have a DataObjectItem own a remote to a
 NativeFileSystemTransferToken. A JavaScript exposed
function will then take the remote NativeFileSystemTransferToken,
redeem it for a NativeFileSystemFileHandle or
 NativeFileSystemDirectoryHandle, and expose the
resulting handle to the Web.

Bug: 1080811
Change-Id: I725626758d61272d548ccbe800014bbe433e02b0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2243998Reviewed-by: Nate Chapin <japhet@chromium.org>
Reviewed-by: Marijn Kruisselbrink <mek@chromium.org>
Reviewed-by: Darwin Huang <huangdarwin@chromium.org>
Commit-Queue: Hazim Mohamed <hazimmohamed@google.com>
Cr-Commit-Position: refs/heads/master@{#784901}

third_party/blink/public/mojom/web_feature/web_feature.mojom

@@ -2679,6 +2679,7 @@ enum WebFeature {
   kV8Window_GetOriginPrivateDirectory_Method = 3343,
   kRTCConstraintEnableRtpDataChannelsTrue = 3344,
   kRTCConstraintEnableRtpDataChannelsFalse = 3345,
+  kNativeFileSystemDragAndDrop = 3346,
 
   // Add new features immediately above this line. Don't change assigned
   // numbers of any item, and don't reuse removed slots.

third_party/blink/renderer/bindings/idl_in_modules.gni

@@ -366,6 +366,7 @@ static_idl_files_in_modules = get_path_info(
           "//third_party/blink/renderer/modules/mediastream/window_media_stream.idl",
           "//third_party/blink/renderer/modules/native_file_system/choose_file_system_entries_options.idl",
           "//third_party/blink/renderer/modules/native_file_system/choose_file_system_entries_options_accepts.idl",
+          "//third_party/blink/renderer/modules/native_file_system/data_transfer_item_native_file_system.idl",
           "//third_party/blink/renderer/modules/native_file_system/file_system_create_writer_options.idl",
           "//third_party/blink/renderer/modules/native_file_system/file_system_directory_handle.idl",
           "//third_party/blink/renderer/modules/native_file_system/file_system_file_handle.idl",

third_party/blink/renderer/core/clipboard/data_object_item.cc

@@ -222,6 +222,29 @@ String DataObjectItem::FileSystemId() const {
   return file_system_id_;
 }
 
+bool DataObjectItem::HasNativeFileSystemEntry() const {
+  return native_file_system_entry_.has_value();
+}
+
+String DataObjectItem::NativeFileSystemFileName() const {
+  DCHECK(HasNativeFileSystemEntry());
+  return native_file_system_entry_->name;
+}
+
+bool DataObjectItem::NativeFileSystemEntryIsDirectory() const {
+  DCHECK(HasNativeFileSystemEntry());
+  return native_file_system_entry_->is_directory;
+}
+
+mojo::PendingRemote<mojom::blink::NativeFileSystemTransferToken>
+DataObjectItem::CloneNativeFileSystemEntryToken() const {
+  DCHECK(HasNativeFileSystemEntry());
+  mojo::PendingRemote<mojom::blink::NativeFileSystemTransferToken> token_clone;
+  native_file_system_entry_->token_remote->Clone(
+      token_clone.InitWithNewPipeAndPassReceiver());
+  return token_clone;
+}
+
 void DataObjectItem::Trace(Visitor* visitor) const {
   visitor->Trace(file_);
   visitor->Trace(system_clipboard_);

third_party/blink/renderer/core/clipboard/data_object_item.h

@@ -31,6 +31,9 @@
 #ifndef THIRD_PARTY_BLINK_RENDERER_CORE_CLIPBOARD_DATA_OBJECT_ITEM_H_
 #define THIRD_PARTY_BLINK_RENDERER_CORE_CLIPBOARD_DATA_OBJECT_ITEM_H_
 
+#include "base/optional.h"
+#include "mojo/public/cpp/bindings/remote.h"
+#include "third_party/blink/public/mojom/native_file_system/native_file_system_transfer_token.mojom-blink.h"
 #include "third_party/blink/renderer/core/core_export.h"
 #include "third_party/blink/renderer/core/fileapi/file.h"
 #include "third_party/blink/renderer/platform/heap/handle.h"
@@ -89,14 +92,40 @@ class CORE_EXPORT DataObjectItem final
   bool HasFileSystemId() const;
   String FileSystemId() const;
 
+  bool HasNativeFileSystemEntry() const;
+  String NativeFileSystemFileName() const;
+  bool NativeFileSystemEntryIsDirectory() const;
+  mojo::PendingRemote<mojom::blink::NativeFileSystemTransferToken>
+  CloneNativeFileSystemEntryToken() const;
+
   void Trace(Visitor*) const;
 
  private:
+  // Incoming DroppedNativeFileSystemEntriy objects are stored using this
+  // intermediary type. This is because this class must own a
+  // Remote<NativeFileSystemTransferToken> to clone tokens, and the Mojo
+  // DroppedNativeFileSystemEntry struct only allows storing a
+  // PendingRemote<NativeFileSystemTransferToken>.
+  struct NativeFileSystemEntryData {
+    NativeFileSystemEntryData(
+        String name,
+        bool is_directory,
+        mojo::Remote<mojom::blink::NativeFileSystemTransferToken> token_remote)
+        : name(name),
+          is_directory(is_directory),
+          token_remote(std::move(token_remote)) {}
+
+    String name;
+    bool is_directory;
+    mojo::Remote<mojom::blink::NativeFileSystemTransferToken> token_remote;
+  };
+
   enum class DataSource {
     kClipboardSource,
     kInternalSource,
   };
 
+  base::Optional<NativeFileSystemEntryData> native_file_system_entry_;
   DataSource source_;
   ItemKind kind_;
   String type_;

third_party/blink/renderer/modules/native_file_system/BUILD.gn

@@ -6,6 +6,8 @@ import("//third_party/blink/renderer/modules/modules.gni")
 
 blink_modules_sources("native_file_system") {
   sources = [
+    "data_transfer_item_native_file_system.cc",
+    "data_transfer_item_native_file_system.h",
     "global_native_file_system.cc",
     "global_native_file_system.h",
     "native_file_system_directory_handle.cc",

third_party/blink/renderer/modules/native_file_system/data_transfer_item_native_file_system.cc

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "third_party/blink/renderer/modules/native_file_system/data_transfer_item_native_file_system.h"
+
+#include "mojo/public/cpp/bindings/remote.h"
+#include "third_party/blink/public/common/browser_interface_broker_proxy.h"
+#include "third_party/blink/public/mojom/native_file_system/native_file_system_directory_handle.mojom-blink.h"
+#include "third_party/blink/public/mojom/native_file_system/native_file_system_file_handle.mojom-blink.h"
+#include "third_party/blink/public/mojom/native_file_system/native_file_system_manager.mojom-blink.h"
+#include "third_party/blink/public/mojom/native_file_system/native_file_system_transfer_token.mojom-blink.h"
+#include "third_party/blink/renderer/core/clipboard/data_object_item.h"
+#include "third_party/blink/renderer/core/clipboard/data_transfer.h"
+#include "third_party/blink/renderer/core/clipboard/data_transfer_item.h"
+#include "third_party/blink/renderer/core/execution_context/execution_context.h"
+#include "third_party/blink/renderer/modules/native_file_system/native_file_system_directory_handle.h"
+#include "third_party/blink/renderer/modules/native_file_system/native_file_system_file_handle.h"
+#include "third_party/blink/renderer/platform/bindings/script_state.h"
+#include "third_party/blink/renderer/platform/wtf/text/wtf_string.h"
+
+namespace blink {
+
+// static
+NativeFileSystemHandle* DataTransferItemNativeFileSystem::getAsFileSystemHandle(
+    ScriptState* script_state,
+    DataTransferItem& data_transfer_item) {
+  if (!data_transfer_item.GetDataTransfer()->CanReadData())
+    return nullptr;
+
+  // If the DataObjectItem doesn't have an associated NativeFileSystemEntry,
+  // return nullptr.
+  if (!data_transfer_item.GetDataObjectItem()->HasNativeFileSystemEntry()) {
+    return nullptr;
+  }
+
+  mojo::Remote<mojom::blink::NativeFileSystemManager> nfs_manager;
+  ExecutionContext* execution_context = ExecutionContext::From(script_state);
+  execution_context->GetBrowserInterfaceBroker().GetInterface(
+      nfs_manager.BindNewPipeAndPassReceiver());
+
+  const DataObjectItem& data_object_item =
+      *data_transfer_item.GetDataObjectItem();
+
+  // Since tokens are move-only, we need to create a clone in order
+  // to preserve the state of |data_object_item| for future calls.
+  mojo::PendingRemote<mojom::blink::NativeFileSystemTransferToken>
+      token_remote = data_object_item.CloneNativeFileSystemEntryToken();
+
+  // Resolve and return the token as a
+  // NativeFileSystemDirectoryHandle/NativeFileSystemFileHandle.
+  if (data_object_item.NativeFileSystemEntryIsDirectory()) {
+    mojo::PendingRemote<mojom::blink::NativeFileSystemDirectoryHandle>
+        dir_remote;
+    nfs_manager->GetDirectoryHandleFromToken(
+        std::move(token_remote), dir_remote.InitWithNewPipeAndPassReceiver());
+    return MakeGarbageCollected<blink::NativeFileSystemDirectoryHandle>(
+        execution_context, data_object_item.NativeFileSystemFileName(),
+        std::move(dir_remote));
+  } else {
+    mojo::PendingRemote<blink::mojom::blink::NativeFileSystemFileHandle>
+        file_remote;
+    nfs_manager->GetFileHandleFromToken(
+        std::move(token_remote), file_remote.InitWithNewPipeAndPassReceiver());
+    return MakeGarbageCollected<blink::NativeFileSystemFileHandle>(
+        execution_context, data_object_item.NativeFileSystemFileName(),
+        std::move(file_remote));
+  }
+}
+
+}  // namespace blink

third_party/blink/renderer/modules/native_file_system/data_transfer_item_native_file_system.h

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_NATIVE_FILE_SYSTEM_DATA_TRANSFER_ITEM_NATIVE_FILE_SYSTEM_H_
+#define THIRD_PARTY_BLINK_RENDERER_MODULES_NATIVE_FILE_SYSTEM_DATA_TRANSFER_ITEM_NATIVE_FILE_SYSTEM_H_
+
+#include "third_party/blink/renderer/core/clipboard/data_transfer_item.h"
+#include "third_party/blink/renderer/core/execution_context/execution_context.h"
+#include "third_party/blink/renderer/modules/native_file_system/native_file_system_handle.h"
+#include "third_party/blink/renderer/platform/bindings/script_state.h"
+
+namespace blink {
+
+class DataTransferItemNativeFileSystem {
+  STATIC_ONLY(DataTransferItemNativeFileSystem);
+
+ public:
+  static NativeFileSystemHandle* getAsFileSystemHandle(ScriptState*,
+                                                       DataTransferItem&);
+};
+
+}  // namespace blink
+
+#endif  // THIRD_PARTY_BLINK_RENDERER_MODULES_NATIVE_FILE_SYSTEM_DATA_TRANSFER_ITEM_NATIVE_FILE_SYSTEM_H_

third_party/blink/renderer/modules/native_file_system/data_transfer_item_native_file_system.idl

+// Copyright 2020 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+[
+    ImplementedAs=DataTransferItemNativeFileSystem,
+    RuntimeEnabled=NativeFileSystemDragAndDrop
+] partial interface DataTransferItem {
+    [CallWith=ScriptState, MeasureAs=NativeFileSystemDragAndDrop] FileSystemHandle? getAsFileSystemHandle();
+};

third_party/blink/renderer/modules/native_file_system/idls.gni

@@ -31,4 +31,5 @@ modules_dictionary_idl_files = [
 modules_dependency_idl_files = [
   "window_native_file_system.idl",
   "worker_global_scope_native_file_system.idl",
+  "data_transfer_item_native_file_system.idl",
 ]

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -1180,6 +1180,10 @@
       origin_trial_feature_name: "NativeFileSystem2",
       origin_trial_os: ["win", "macosx", "linux", "chromeos"],
     },
+    {
+      name: "NativeFileSystemDragAndDrop",
+      status: "test"
+    },
     {
       name: "NativeIO",
       status: "experimental",

third_party/blink/web_tests/webexposed/global-interface-listing-expected.txt

@@ -1480,6 +1480,7 @@ interface DataTransferItem
     getter type
     method constructor
     method getAsFile
+    method getAsFileSystemHandle
     method getAsString
     method webkitGetAsEntry
 interface DataTransferItemList

tools/metrics/histograms/enums.xml

@@ -28255,6 +28255,7 @@ Called by update_use_counter_feature_enum.py.-->
   <int value="3343" label="V8Window_GetOriginPrivateDirectory_Method"/>
   <int value="3344" label="RTCConstraintEnableRtpDataChannelsTrue"/>
   <int value="3345" label="RTCConstraintEnableRtpDataChannelsFalse"/>
+  <int value="3346" label="NativeFileSystemDragAndDrop"/>
 </enum>
 
 <enum name="FeaturePolicyAllowlistType">