1 files changed, 556 insertions, 0 deletions
diff --git a/dom/events/DataTransferItem.cpp b/dom/events/DataTransferItem.cpp
new file mode 100644
index 0000000000..cc4496871a
--- /dev/null
+++ b/dom/events/DataTransferItem.cpp
@@ -0,0 +1,556 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "DataTransferItem.h"
+#include "DataTransferItemList.h"
+
+#include "mozilla/ContentEvents.h"
+#include "mozilla/EventForwards.h"
+#include "mozilla/dom/DataTransferItemBinding.h"
+#include "mozilla/dom/Directory.h"
+#include "mozilla/dom/Event.h"
+#include "mozilla/dom/FileSystem.h"
+#include "mozilla/dom/FileSystemDirectoryEntry.h"
+#include "mozilla/dom/FileSystemFileEntry.h"
+#include "nsIClipboard.h"
+#include "nsISupportsPrimitives.h"
+#include "nsIScriptObjectPrincipal.h"
+#include "nsNetUtil.h"
+#include "nsQueryObject.h"
+#include "nsContentUtils.h"
+#include "nsVariant.h"
+
+namespace {
+
+struct FileMimeNameData
+{
+  const char* mMimeName;
+  const char* mFileName;
+};
+
+FileMimeNameData kFileMimeNameMap[] = {
+  { kFileMime, "GenericFileName" },
+  { kPNGImageMime, "GenericImageNamePNG" },
+};
+
+} // anonymous namespace
+
+namespace mozilla {
+namespace dom {
+
+NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(DataTransferItem, mData,
+                                      mPrincipal, mDataTransfer, mCachedFile)
+NS_IMPL_CYCLE_COLLECTING_ADDREF(DataTransferItem)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(DataTransferItem)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(DataTransferItem)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END
+
+JSObject*
+DataTransferItem::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
+{
+  return DataTransferItemBinding::Wrap(aCx, this, aGivenProto);
+}
+
+already_AddRefed<DataTransferItem>
+DataTransferItem::Clone(DataTransfer* aDataTransfer) const
+{
+  MOZ_ASSERT(aDataTransfer);
+
+  RefPtr<DataTransferItem> it = new DataTransferItem(aDataTransfer, mType);
+
+  // Copy over all of the fields
+  it->mKind = mKind;
+  it->mIndex = mIndex;
+  it->mData = mData;
+  it->mPrincipal = mPrincipal;
+  it->mChromeOnly = mChromeOnly;
+
+  return it.forget();
+}
+
+void
+DataTransferItem::SetData(nsIVariant* aData)
+{
+  // Invalidate our file cache, we will regenerate it with the new data
+  mCachedFile = nullptr;
+
+  if (!aData) {
+    // We are holding a temporary null which will later be filled.
+    // These are provided by the system, and have guaranteed properties about
+    // their kind based on their type.
+    MOZ_ASSERT(!mType.IsEmpty());
+
+    mKind = KIND_STRING;
+    for (uint32_t i = 0; i < ArrayLength(kFileMimeNameMap); ++i) {
+      if (mType.EqualsASCII(kFileMimeNameMap[i].mMimeName)) {
+        mKind = KIND_FILE;
+        break;
+      }
+    }
+
+    mData = nullptr;
+    return;
+  }
+
+  mData = aData;
+  mKind = KindFromData(mData);
+}
+
+/* static */ DataTransferItem::eKind
+DataTransferItem::KindFromData(nsIVariant* aData)
+{
+  nsCOMPtr<nsISupports> supports;
+  nsresult rv = aData->GetAsISupports(getter_AddRefs(supports));
+  if (NS_SUCCEEDED(rv) && supports) {
+    // Check if we have one of the supported file data formats
+    if (nsCOMPtr<nsIDOMBlob>(do_QueryInterface(supports)) ||
+        nsCOMPtr<BlobImpl>(do_QueryInterface(supports)) ||
+        nsCOMPtr<nsIFile>(do_QueryInterface(supports))) {
+      return KIND_FILE;
+    }
+  }
+
+  nsAutoString string;
+  // If we can't get the data type as a string, that means that the object
+  // should be considered to be of the "other" type. This is impossible
+  // through the APIs defined by the spec, but we provide extra Moz* APIs,
+  // which allow setting of non-string data. We determine whether we can
+  // consider it a string, by calling GetAsAString, and checking for success.
+  rv = aData->GetAsAString(string);
+  if (NS_SUCCEEDED(rv)) {
+    return KIND_STRING;
+  }
+
+  return KIND_OTHER;
+}
+
+void
+DataTransferItem::FillInExternalData()
+{
+  if (mData) {
+    return;
+  }
+
+  NS_ConvertUTF16toUTF8 utf8format(mType);
+  const char* format = utf8format.get();
+  if (strcmp(format, "text/plain") == 0) {
+    format = kUnicodeMime;
+  } else if (strcmp(format, "text/uri-list") == 0) {
+    format = kURLDataMime;
+  }
+
+  nsCOMPtr<nsITransferable> trans =
+    do_CreateInstance("@mozilla.org/widget/transferable;1");
+  if (NS_WARN_IF(!trans)) {
+    return;
+  }
+
+  trans->Init(nullptr);
+  trans->AddDataFlavor(format);
+
+  if (mDataTransfer->GetEventMessage() == ePaste) {
+    MOZ_ASSERT(mIndex == 0, "index in clipboard must be 0");
+
+    nsCOMPtr<nsIClipboard> clipboard =
+      do_GetService("@mozilla.org/widget/clipboard;1");
+    if (!clipboard || mDataTransfer->ClipboardType() < 0) {
+      return;
+    }
+
+    nsresult rv = clipboard->GetData(trans, mDataTransfer->ClipboardType());
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+  } else {
+    nsCOMPtr<nsIDragSession> dragSession = nsContentUtils::GetDragSession();
+    if (!dragSession) {
+      return;
+    }
+
+    nsresult rv = dragSession->GetData(trans, mIndex);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return;
+    }
+  }
+
+  uint32_t length = 0;
+  nsCOMPtr<nsISupports> data;
+  nsresult rv = trans->GetTransferData(format, getter_AddRefs(data), &length);
+  if (NS_WARN_IF(NS_FAILED(rv) || !data)) {
+    return;
+  }
+
+  // Fill the variant
+  RefPtr<nsVariantCC> variant = new nsVariantCC();
+
+  eKind oldKind = Kind();
+  if (oldKind == KIND_FILE) {
+    // Because this is an external piece of data, mType is one of kFileMime,
+    // kPNGImageMime, kJPEGImageMime, or kGIFImageMime. Some of these types
+    // are passed in as a nsIInputStream which must be converted to a
+    // dom::File before storing.
+    if (nsCOMPtr<nsIInputStream> istream = do_QueryInterface(data)) {
+      RefPtr<File> file = CreateFileFromInputStream(istream);
+      if (NS_WARN_IF(!file)) {
+        return;
+      }
+      data = do_QueryObject(file);
+    }
+
+    variant->SetAsISupports(data);
+  } else {
+    // We have an external piece of string data. Extract it and store it in the variant
+    MOZ_ASSERT(oldKind == KIND_STRING);
+
+    nsCOMPtr<nsISupportsString> supportsstr = do_QueryInterface(data);
+    if (supportsstr) {
+      nsAutoString str;
+      supportsstr->GetData(str);
+      variant->SetAsAString(str);
+    } else {
+      nsCOMPtr<nsISupportsCString> supportscstr = do_QueryInterface(data);
+      if (supportscstr) {
+        nsAutoCString str;
+        supportscstr->GetData(str);
+        variant->SetAsACString(str);
+      }
+    }
+  }
+
+  SetData(variant);
+
+  if (oldKind != Kind()) {
+    NS_WARNING("Clipboard data provided by the OS does not match predicted kind");
+    mDataTransfer->TypesListMayHaveChanged();
+  }
+}
+
+void
+DataTransferItem::GetType(nsAString& aType)
+{
+  // If we don't have a File, we can just put whatever our recorded internal
+  // type is.
+  if (Kind() != KIND_FILE) {
+    aType = mType;
+    return;
+  }
+
+  // If we do have a File, then we need to look at our File object to discover
+  // what its mime type is. We can use the System Principal here, as this
+  // information should be avaliable even if the data is currently inaccessible
+  // (for example during a dragover).
+  //
+  // XXX: This seems inefficient, as it seems like we should be able to get this
+  // data without getting the entire File object, which may require talking to
+  // the OS.
+  ErrorResult rv;
+  RefPtr<File> file = GetAsFile(*nsContentUtils::GetSystemPrincipal(), rv);
+  MOZ_ASSERT(!rv.Failed(), "Failed to get file data with system principal");
+
+  // If we don't actually have a file, fall back to returning the internal type.
+  if (NS_WARN_IF(!file)) {
+    aType = mType;
+    return;
+  }
+
+  file->GetType(aType);
+}
+
+already_AddRefed<File>
+DataTransferItem::GetAsFile(nsIPrincipal& aSubjectPrincipal,
+                            ErrorResult& aRv)
+{
+  // This is done even if we have an mCachedFile, as it performs the necessary
+  // permissions checks to ensure that we are allowed to access this type.
+  nsCOMPtr<nsIVariant> data = Data(&aSubjectPrincipal, aRv);
+  if (NS_WARN_IF(!data || aRv.Failed())) {
+    return nullptr;
+  }
+
+  // We have to check our kind after getting the data, because if we have
+  // external data and the OS lied to us (which unfortunately does happen
+  // sometimes), then we might not have the same type of data as we did coming
+  // into this function.
+  if (NS_WARN_IF(mKind != KIND_FILE)) {
+    return nullptr;
+  }
+
+  // Generate the dom::File from the stored data, caching it so that the
+  // same object is returned in the future.
+  if (!mCachedFile) {
+    nsCOMPtr<nsISupports> supports;
+    aRv = data->GetAsISupports(getter_AddRefs(supports));
+    MOZ_ASSERT(!aRv.Failed() && supports,
+               "File objects should be stored as nsISupports variants");
+    if (aRv.Failed() || !supports) {
+      return nullptr;
+    }
+
+    if (nsCOMPtr<nsIDOMBlob> domBlob = do_QueryInterface(supports)) {
+      Blob* blob = static_cast<Blob*>(domBlob.get());
+      mCachedFile = blob->ToFile();
+    } else if (nsCOMPtr<BlobImpl> blobImpl = do_QueryInterface(supports)) {
+      MOZ_ASSERT(blobImpl->IsFile());
+      mCachedFile = File::Create(mDataTransfer, blobImpl);
+    } else if (nsCOMPtr<nsIFile> ifile = do_QueryInterface(supports)) {
+      mCachedFile = File::CreateFromFile(mDataTransfer, ifile);
+    } else {
+      MOZ_ASSERT(false, "One of the above code paths should be taken");
+      return nullptr;
+    }
+  }
+
+  RefPtr<File> file = mCachedFile;
+  return file.forget();
+}
+
+already_AddRefed<FileSystemEntry>
+DataTransferItem::GetAsEntry(nsIPrincipal& aSubjectPrincipal,
+                             ErrorResult& aRv)
+{
+  RefPtr<File> file = GetAsFile(aSubjectPrincipal, aRv);
+  if (NS_WARN_IF(aRv.Failed()) || !file) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIGlobalObject> global;
+  // This is annoying, but DataTransfer may have various things as parent.
+  nsCOMPtr<EventTarget> target =
+    do_QueryInterface(mDataTransfer->GetParentObject());
+  if (target) {
+    global = target->GetOwnerGlobal();
+  } else {
+    nsCOMPtr<nsIDOMEvent> event =
+      do_QueryInterface(mDataTransfer->GetParentObject());
+    if (event) {
+      global = event->InternalDOMEvent()->GetParentObject();
+    }
+  }
+
+  if (!global) {
+    return nullptr;
+  }
+
+  RefPtr<FileSystem> fs = FileSystem::Create(global);
+  RefPtr<FileSystemEntry> entry;
+  BlobImpl* impl = file->Impl();
+  MOZ_ASSERT(impl);
+
+  if (impl->IsDirectory()) {
+    nsAutoString fullpath;
+    impl->GetMozFullPathInternal(fullpath, aRv);
+    if (aRv.Failed()) {
+      aRv.SuppressException();
+      return nullptr;
+    }
+
+    nsCOMPtr<nsIFile> directoryFile;
+    // fullPath is already in unicode, we don't have to use
+    // NS_NewNativeLocalFile.
+    nsresult rv = NS_NewLocalFile(fullpath, true,
+                                  getter_AddRefs(directoryFile));
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return nullptr;
+    }
+
+    RefPtr<Directory> directory = Directory::Create(global, directoryFile);
+    entry = new FileSystemDirectoryEntry(global, directory, nullptr, fs);
+  } else {
+    entry = new FileSystemFileEntry(global, file, nullptr, fs);
+  }
+
+  Sequence<RefPtr<FileSystemEntry>> entries;
+  if (!entries.AppendElement(entry, fallible)) {
+    return nullptr;
+  }
+
+  fs->CreateRoot(entries);
+  return entry.forget();
+}
+
+already_AddRefed<File>
+DataTransferItem::CreateFileFromInputStream(nsIInputStream* aStream)
+{
+  const char* key = nullptr;
+  for (uint32_t i = 0; i < ArrayLength(kFileMimeNameMap); ++i) {
+    if (mType.EqualsASCII(kFileMimeNameMap[i].mMimeName)) {
+      key = kFileMimeNameMap[i].mFileName;
+      break;
+    }
+  }
+  if (!key) {
+    MOZ_ASSERT_UNREACHABLE("Unsupported mime type");
+    key = "GenericFileName";
+  }
+
+  nsXPIDLString fileName;
+  nsresult rv = nsContentUtils::GetLocalizedString(nsContentUtils::eDOM_PROPERTIES,
+                                                   key, fileName);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  uint64_t available;
+  rv = aStream->Available(&available);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  void* data = nullptr;
+  rv = NS_ReadInputStreamToBuffer(aStream, &data, available);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  return File::CreateMemoryFile(mDataTransfer, data, available, fileName,
+                                mType, PR_Now());
+}
+
+void
+DataTransferItem::GetAsString(FunctionStringCallback* aCallback,
+                              nsIPrincipal& aSubjectPrincipal,
+                              ErrorResult& aRv)
+{
+  if (!aCallback) {
+    return;
+  }
+
+  // Theoretically this should be done inside of the runnable, as it might be an
+  // expensive operation on some systems, however we wouldn't get access to the
+  // NS_ERROR_DOM_SECURITY_ERROR messages which may be raised by this method.
+  nsCOMPtr<nsIVariant> data = Data(&aSubjectPrincipal, aRv);
+  if (NS_WARN_IF(!data || aRv.Failed())) {
+    return;
+  }
+
+  // We have to check our kind after getting the data, because if we have
+  // external data and the OS lied to us (which unfortunately does happen
+  // sometimes), then we might not have the same type of data as we did coming
+  // into this function.
+  if (NS_WARN_IF(mKind != KIND_STRING)) {
+    return;
+  }
+
+  nsAutoString stringData;
+  nsresult rv = data->GetAsAString(stringData);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return;
+  }
+
+  // Dispatch the callback to the main thread
+  class GASRunnable final : public Runnable
+  {
+  public:
+    GASRunnable(FunctionStringCallback* aCallback,
+                const nsAString& aStringData)
+      : mCallback(aCallback), mStringData(aStringData)
+    {}
+
+    NS_IMETHOD Run() override
+    {
+      ErrorResult rv;
+      mCallback->Call(mStringData, rv);
+      NS_WARNING_ASSERTION(!rv.Failed(), "callback failed");
+      return rv.StealNSResult();
+    }
+  private:
+    RefPtr<FunctionStringCallback> mCallback;
+    nsString mStringData;
+  };
+
+  RefPtr<GASRunnable> runnable = new GASRunnable(aCallback, stringData);
+  rv = NS_DispatchToMainThread(runnable);
+  if (NS_FAILED(rv)) {
+    NS_WARNING("NS_DispatchToMainThread Failed in "
+               "DataTransferItem::GetAsString!");
+  }
+}
+
+already_AddRefed<nsIVariant>
+DataTransferItem::DataNoSecurityCheck()
+{
+  if (!mData) {
+    FillInExternalData();
+  }
+  nsCOMPtr<nsIVariant> data = mData;
+  return data.forget();
+}
+
+already_AddRefed<nsIVariant>
+DataTransferItem::Data(nsIPrincipal* aPrincipal, ErrorResult& aRv)
+{
+  MOZ_ASSERT(aPrincipal);
+
+  nsCOMPtr<nsIVariant> variant = DataNoSecurityCheck();
+
+  // If the inbound principal is system, we can skip the below checks, as
+  // they will trivially succeed.
+  if (nsContentUtils::IsSystemPrincipal(aPrincipal)) {
+    return variant.forget();
+  }
+
+  MOZ_ASSERT(!ChromeOnly(), "Non-chrome code shouldn't see a ChromeOnly DataTransferItem");
+  if (ChromeOnly()) {
+    aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return nullptr;
+  }
+
+  bool checkItemPrincipal = mDataTransfer->IsCrossDomainSubFrameDrop() ||
+    (mDataTransfer->GetEventMessage() != eDrop &&
+     mDataTransfer->GetEventMessage() != ePaste);
+
+  // Check if the caller is allowed to access the drag data. Callers with
+  // chrome privileges can always read the data. During the
+  // drop event, allow retrieving the data except in the case where the
+  // source of the drag is in a child frame of the caller. In that case,
+  // we only allow access to data of the same principal. During other events,
+  // only allow access to the data with the same principal.
+  //
+  // We don't want to fail with an exception in this siutation, rather we want
+  // to just pretend as though the stored data is "nullptr". This is consistent
+  // with Chrome's behavior and is less surprising for web applications which
+  // don't expect execptions to be raised when performing certain operations.
+  if (Principal() && checkItemPrincipal &&
+      !aPrincipal->Subsumes(Principal())) {
+    return nullptr;
+  }
+
+  if (!variant) {
+    return nullptr;
+  }
+
+  nsCOMPtr<nsISupports> data;
+  nsresult rv = variant->GetAsISupports(getter_AddRefs(data));
+  if (NS_SUCCEEDED(rv) && data) {
+    nsCOMPtr<EventTarget> pt = do_QueryInterface(data);
+    if (pt) {
+      nsIScriptContext* c = pt->GetContextForEventHandlers(&rv);
+      if (NS_WARN_IF(NS_FAILED(rv) || !c)) {
+        return nullptr;
+      }
+
+      nsIGlobalObject* go = c->GetGlobalObject();
+      if (NS_WARN_IF(!go)) {
+        return nullptr;
+      }
+
+      nsCOMPtr<nsIScriptObjectPrincipal> sp = do_QueryInterface(go);
+      MOZ_ASSERT(sp, "This cannot fail on the main thread.");
+
+      nsIPrincipal* dataPrincipal = sp->GetPrincipal();
+      if (NS_WARN_IF(!dataPrincipal || !aPrincipal->Equals(dataPrincipal))) {
+        return nullptr;
+      }
+    }
+  }
+
+  return variant.forget();
+}
+
+} // namespace dom
+} // namespace mozilla