nsContentAreaDragDrop.cpp

mozilla-central/dom/base/nsContentAreaDragDrop.cpp (file symbol)

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* 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 "nsReadableUtils.h"

// Local Includes

#include "nsContentAreaDragDrop.h"

// Helper Classes

#include "nsString.h"

// Interfaces needed to be included

#include "nsCopySupport.h"

#include "nsISelectionController.h"

#include "nsPIDOMWindow.h"

#include "nsIFormControl.h"

#include "nsITransferable.h"

#include "nsComponentManagerUtils.h"

#include "nsXPCOM.h"

#include "nsISupportsPrimitives.h"

#include "nsServiceManagerUtils.h"

#include "nsNetUtil.h"

#include "nsIFile.h"

#include "nsFrameLoader.h"

#include "nsFrameLoaderOwner.h"

#include "nsIContent.h"

#include "nsIContentInlines.h"

#include "nsIContentPolicy.h"

#include "nsIImageLoadingContent.h"

#include "nsUnicharUtils.h"

#include "nsIURL.h"

#include "nsIURIMutator.h"

#include "mozilla/dom/Document.h"

#include "nsICookieJarSettings.h"

#include "nsIPrincipal.h"

#include "nsIWebBrowserPersist.h"

#include "nsEscape.h"

#include "nsContentUtils.h"

#include "nsIMIMEService.h"

#include "imgIContainer.h"

#include "imgIRequest.h"

#include "mozilla/dom/DataTransfer.h"

#include "nsIMIMEInfo.h"

#include "nsRange.h"

#include "BrowserParent.h"

#include "mozilla/TextControlElement.h"

#include "mozilla/dom/BrowsingContext.h"

#include "mozilla/dom/Element.h"

#include "mozilla/dom/HTMLAreaElement.h"

#include "mozilla/dom/HTMLAnchorElement.h"

#include "mozilla/dom/Selection.h"

#include "nsVariant.h"

#include "nsQueryObject.h"

using namespace mozilla;

using namespace mozilla::dom;

using mozilla::IgnoreErrors;

class MOZ_STACK_CLASS DragDataProducer {

 public:

  DragDataProducer(nsPIDOMWindowOuter* aWindow, nsIContent* aTarget,

                   nsIContent* aSelectionTargetNode, bool aIsAltKeyPressed);

  nsresult Produce(DataTransfer* aDataTransfer, bool* aCanDrag,

                   Selection** aSelection, nsIContent** aDragNode,

                   nsIContentSecurityPolicy** aCsp,

                   nsICookieJarSettings** aCookieJarSettings);

 private:

  // @param aHidden true, iff the data should be hidden from non-chrome code.

  void AddString(DataTransfer* aDataTransfer, const nsAString& aFlavor,

                 const nsAString& aData, nsIPrincipal* aPrincipal,

                 bool aHidden = false);

  nsresult AddStringsToDataTransfer(nsIContent* aDragNode,

                                    DataTransfer* aDataTransfer);

  nsresult GetImageData(imgIContainer* aImage, imgIRequest* aRequest);

  static nsresult GetDraggableSelectionData(Selection* inSelection,

                                            nsIContent* inRealTargetNode,

                                            nsIContent** outImageOrLinkNode,

                                            bool* outDragSelectedText);

  [[nodiscard]] static nsresult GetAnchorURL(nsIContent* inNode,

                                             nsAString& outURL);

  static void CreateLinkText(const nsAString& inURL, const nsAString& inText,

                             nsAString& outLinkText);

  nsCOMPtr<nsPIDOMWindowOuter> mWindow;

  nsCOMPtr<nsIContent> mTarget;

  nsCOMPtr<nsIContent> mSelectionTargetNode;

  bool mIsAltKeyPressed;

  nsString mUrlString;

  nsString mImageSourceString;

  nsString mImageDestFileName;

#if defined(XP_MACOSX)

  nsString mImageRequestMime;

#endif

  nsString mTitleString;

  // will be filled automatically if you fill urlstring

  nsString mHtmlString;

  nsString mContextString;

  nsString mInfoString;

  bool mIsAnchor;

  nsCOMPtr<imgIContainer> mImage;

};

nsresult nsContentAreaDragDrop::GetDragData(

    nsPIDOMWindowOuter* aWindow, nsIContent* aTarget,

    nsIContent* aSelectionTargetNode, bool aIsAltKeyPressed,

    DataTransfer* aDataTransfer, bool* aCanDrag, Selection** aSelection,

    nsIContent** aDragNode, nsIContentSecurityPolicy** aCsp,

    nsICookieJarSettings** aCookieJarSettings) {

  NS_ENSURE_TRUE(aSelectionTargetNode, NS_ERROR_INVALID_ARG);

  *aCanDrag = true;

  DragDataProducer provider(aWindow, aTarget, aSelectionTargetNode,

                            aIsAltKeyPressed);

  return provider.Produce(aDataTransfer, aCanDrag, aSelection, aDragNode, aCsp,

                          aCookieJarSettings);

NS_IMPL_ISUPPORTS(nsContentAreaDragDropDataProvider, nsIFlavorDataProvider)

// SaveURIToFile

// used on platforms where it's possible to drag items (e.g. images)

// into the file system

nsresult nsContentAreaDragDropDataProvider::SaveURIToFile(

    nsIURI* inSourceURI, nsIPrincipal* inTriggeringPrincipal,

    nsICookieJarSettings* inCookieJarSettings, nsIFile* inDestFile,

    nsContentPolicyType inContentPolicyType, bool isPrivate) {

  nsCOMPtr<nsIURL> sourceURL = do_QueryInterface(inSourceURI);

  if (!sourceURL) {

    return NS_ERROR_NO_INTERFACE;

  nsresult rv = inDestFile->CreateUnique(nsIFile::NORMAL_FILE_TYPE, 0600);

  NS_ENSURE_SUCCESS(rv, rv);

  // we rely on the fact that the WPB is refcounted by the channel etc,

  // so we don't keep a ref to it. It will die when finished.

  nsCOMPtr<nsIWebBrowserPersist> persist = do_CreateInstance(

      "@mozilla.org/embedding/browser/nsWebBrowserPersist;1", &rv);

  NS_ENSURE_SUCCESS(rv, rv);

  persist->SetPersistFlags(

      nsIWebBrowserPersist::PERSIST_FLAGS_AUTODETECT_APPLY_CONVERSION);

  // referrer policy can be anything since the referrer is nullptr

  return persist->SaveURI(inSourceURI, inTriggeringPrincipal, 0, nullptr,

                          inCookieJarSettings, nullptr, nullptr, inDestFile,

                          inContentPolicyType, isPrivate);

/*

 * Check if the provided filename extension is valid for the MIME type and

 * return the MIME type's primary extension.

 * @param aExtension           [in]  the extension to check

 * @param aMimeType            [in]  the MIME type to check the extension with

 * @param aIsValidExtension    [out] true if |aExtension| is valid for

 *                                   |aMimeType|

 * @param aPrimaryExtension    [out] the primary extension for the MIME type

 *                                   to potentially be used as a replacement

 *                                   for |aExtension|

*/

nsresult CheckAndGetExtensionForMime(const nsCString& aExtension,

                                     const nsCString& aMimeType,

                                     bool* aIsValidExtension,

                                     nsACString* aPrimaryExtension) {

  nsresult rv;

  nsCOMPtr<nsIMIMEService> mimeService = do_GetService("@mozilla.org/mime;1");

  if (NS_WARN_IF(!mimeService)) {

    return NS_ERROR_FAILURE;

  nsCOMPtr<nsIMIMEInfo> mimeInfo;

  rv = mimeService->GetFromTypeAndExtension(aMimeType, ""_ns,

                                            getter_AddRefs(mimeInfo));

  NS_ENSURE_SUCCESS(rv, rv);

  mimeInfo->GetPrimaryExtension(*aPrimaryExtension);

  if (aExtension.IsEmpty()) {

    *aIsValidExtension = false;

    return NS_OK;

  rv = mimeInfo->ExtensionExists(aExtension, aIsValidExtension);

  NS_ENSURE_SUCCESS(rv, rv);

  return NS_OK;

// This is our nsIFlavorDataProvider callback. There are several

// assumptions here that make this work:

//

// 1. Someone put a kFilePromiseURLMime flavor into the transferable

//    with the source URI of the file to save (as a string). We did

//    that in AddStringsToDataTransfer.

//

// 2. Someone put a kFilePromiseDirectoryMime flavor into the

//    transferable with an nsIFile for the directory we are to

//    save in. That has to be done by platform-specific code (in

//    widget), which gets the destination directory from

//    OS-specific drag information.

//

NS_IMETHODIMP

nsContentAreaDragDropDataProvider::GetFlavorData(nsITransferable* aTransferable,

                                                 const char* aFlavor,

                                                 nsISupports** aData) {

  NS_ENSURE_ARG_POINTER(aData);

  *aData = nullptr;

  nsresult rv = NS_ERROR_NOT_IMPLEMENTED;

  if (strcmp(aFlavor, kFilePromiseMime) == 0) {

    // get the URI from the kFilePromiseURLMime flavor

    NS_ENSURE_ARG(aTransferable);

    nsCOMPtr<nsISupports> tmp;

    rv = aTransferable->GetTransferData(kFilePromiseURLMime,

                                        getter_AddRefs(tmp));

    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsISupportsString> supportsString = do_QueryInterface(tmp);

    if (!supportsString) return NS_ERROR_FAILURE;

    nsAutoString sourceURLString;

    supportsString->GetData(sourceURLString);

    if (sourceURLString.IsEmpty()) return NS_ERROR_FAILURE;

    nsCOMPtr<nsIURI> sourceURI;

    rv = NS_NewURI(getter_AddRefs(sourceURI), sourceURLString);

    NS_ENSURE_SUCCESS(rv, rv);

    rv = aTransferable->GetTransferData(kFilePromiseDestFilename,

                                        getter_AddRefs(tmp));

    NS_ENSURE_SUCCESS(rv, rv);

    supportsString = do_QueryInterface(tmp);

    if (!supportsString) return NS_ERROR_FAILURE;

    nsAutoString targetFilename;

    supportsString->GetData(targetFilename);

    if (targetFilename.IsEmpty()) return NS_ERROR_FAILURE;

#if defined(XP_MACOSX)

    // Use the image request's MIME type to ensure the filename's

    // extension is compatible with the OS's handler for this type.

    // If it isn't, or is missing, replace the extension with the

    // primary extension. On Mac, do this in the parent process

    // because sandboxing blocks access to MIME-handler info from

    // content processes.

    if (XRE_IsParentProcess()) {

      rv = aTransferable->GetTransferData(kImageRequestMime,

                                          getter_AddRefs(tmp));

      NS_ENSURE_SUCCESS(rv, rv);

      supportsString = do_QueryInterface(tmp);

      if (!supportsString) return NS_ERROR_FAILURE;

      nsAutoString contentType;

      supportsString->GetData(contentType);

      nsCOMPtr<nsIMIMEService> mimeService =

          do_GetService("@mozilla.org/mime;1");

      if (NS_WARN_IF(!mimeService)) {

        return NS_ERROR_FAILURE;

      mimeService->ValidateFileNameForSaving(

          targetFilename, NS_ConvertUTF16toUTF8(contentType),

          nsIMIMEService::VALIDATE_DEFAULT, targetFilename);

    } else {

      // make the filename safe for the filesystem

      targetFilename.ReplaceChar(

          u"" FILE_PATH_SEPARATOR FILE_ILLEGAL_CHARACTERS, u'-');

#endif /* defined(XP_MACOSX) */

    // get the target directory from the kFilePromiseDirectoryMime

    // flavor

    nsCOMPtr<nsISupports> dirPrimitive;

    rv = aTransferable->GetTransferData(kFilePromiseDirectoryMime,

                                        getter_AddRefs(dirPrimitive));

    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsIFile> destDirectory = do_QueryInterface(dirPrimitive);

    if (!destDirectory) return NS_ERROR_FAILURE;

    nsCOMPtr<nsIFile> file;

    rv = destDirectory->Clone(getter_AddRefs(file));

    NS_ENSURE_SUCCESS(rv, rv);

    file->Append(targetFilename);

    bool isPrivate = aTransferable->GetIsPrivateData();

    nsCOMPtr<nsIPrincipal> principal = aTransferable->GetDataPrincipal();

    nsContentPolicyType contentPolicyType =

        aTransferable->GetContentPolicyType();

    nsCOMPtr<nsICookieJarSettings> cookieJarSettings =

        aTransferable->GetCookieJarSettings();

    rv = SaveURIToFile(sourceURI, principal, cookieJarSettings, file,

                       contentPolicyType, isPrivate);

    // send back an nsIFile

    if (NS_SUCCEEDED(rv)) {

      CallQueryInterface(file, aData);

  return rv;

DragDataProducer::DragDataProducer(nsPIDOMWindowOuter* aWindow,

                                   nsIContent* aTarget,

                                   nsIContent* aSelectionTargetNode,

                                   bool aIsAltKeyPressed)

    : mWindow(aWindow),

      mTarget(aTarget),

      mSelectionTargetNode(aSelectionTargetNode),

      mIsAltKeyPressed(aIsAltKeyPressed),

      mIsAnchor(false) {}

static nsIContent* FindDragTarget(nsIContent* aContent) {

  for (nsIContent* content = aContent; content;

       content = content->GetFlattenedTreeParent()) {

    if (nsContentUtils::ContentIsDraggable(content)) {

      return content;

  return nullptr;

//

// GetAnchorURL

//

nsresult DragDataProducer::GetAnchorURL(nsIContent* aContent, nsAString& aURL) {

  aURL.Truncate();

  auto* element = Element::FromNodeOrNull(aContent);

  if (!element || !element->IsLink()) {

    return NS_OK;

  nsCOMPtr<nsIURI> linkURI = element->GetHrefURI();

  if (!linkURI) {

    return NS_OK;

  nsAutoCString spec;

  nsresult rv = linkURI->GetSpec(spec);

  NS_ENSURE_SUCCESS(rv, rv);

  nsIScriptSecurityManager* secMan = nsContentUtils::GetSecurityManager();

  rv = secMan->CheckLoadURIStrWithPrincipal(aContent->NodePrincipal(), spec, 0);

  NS_ENSURE_SUCCESS(rv, rv);

  CopyUTF8toUTF16(spec, aURL);

  return NS_OK;

//

// CreateLinkText

//

// Creates the html for an anchor in the form

//  <a href="inURL">inText</a>

//

void DragDataProducer::CreateLinkText(const nsAString& inURL,

                                      const nsAString& inText,

                                      nsAString& outLinkText) {

  // use a temp var in case |inText| is the same string as

  // |outLinkText| to avoid overwriting it while building up the

  // string in pieces.

  nsAutoString linkText(u"<a href=\""_ns + inURL + u"\">"_ns + inText +

                        u"</a>"_ns);

  outLinkText = linkText;

nsresult DragDataProducer::GetImageData(imgIContainer* aImage,

                                        imgIRequest* aRequest) {

  nsCOMPtr<nsIURI> imgUri = aRequest->GetURI();

  nsCOMPtr<nsIURL> imgUrl(do_QueryInterface(imgUri));

  if (imgUrl) {

    nsAutoCString spec;

    nsresult rv = imgUrl->GetSpec(spec);

    NS_ENSURE_SUCCESS(rv, rv);

    // pass out the image source string

    CopyUTF8toUTF16(spec, mImageSourceString);

    nsCString mimeType;

    aRequest->GetMimeType(getter_Copies(mimeType));

    nsAutoCString fileName;

    aRequest->GetFileName(fileName);

#if defined(XP_MACOSX)

    // Save the MIME type so we can make sure the extension

    // is compatible (and replace it if it isn't) when the

    // image is dropped. On Mac, we need to get the OS MIME

    // handler information in the parent due to sandboxing.

    CopyUTF8toUTF16(mimeType, mImageRequestMime);

    CopyUTF8toUTF16(fileName, mImageDestFileName);

#else

    nsCOMPtr<nsIMIMEService> mimeService = do_GetService("@mozilla.org/mime;1");

    if (NS_WARN_IF(!mimeService)) {

      return NS_ERROR_FAILURE;

    CopyUTF8toUTF16(fileName, mImageDestFileName);

    mimeService->ValidateFileNameForSaving(mImageDestFileName, mimeType,

                                           nsIMIMEService::VALIDATE_DEFAULT,

                                           mImageDestFileName);

#endif

    // and the image object

    mImage = aImage;

  return NS_OK;

nsresult DragDataProducer::Produce(DataTransfer* aDataTransfer, bool* aCanDrag,

                                   Selection** aSelection,

                                   nsIContent** aDragNode,

                                   nsIContentSecurityPolicy** aCsp,

                                   nsICookieJarSettings** aCookieJarSettings) {

  MOZ_ASSERT(aCanDrag && aSelection && aDataTransfer && aDragNode,

             "null pointer passed to Produce");

  NS_ASSERTION(mWindow, "window not set");

  NS_ASSERTION(mSelectionTargetNode,

               "selection target node should have been set");

  *aDragNode = nullptr;

  nsresult rv;

  nsIContent* dragNode = nullptr;

  *aSelection = nullptr;

  // Find the selection to see what we could be dragging and if what we're

  // dragging is in what is selected. If this is an editable textbox, use

  // the textbox's selection, otherwise use the window's selection.

  RefPtr<Selection> selection;

  nsIContent* editingElement = mSelectionTargetNode->IsEditable()

                                   ? mSelectionTargetNode->GetEditingHost()

                                   : nullptr;

  RefPtr<TextControlElement> textControlElement =

      TextControlElement::GetTextControlElementFromEditingHost(editingElement);

  if (textControlElement) {

    nsISelectionController* selcon =

        textControlElement->GetSelectionController();

    if (selcon) {

      selection =

          selcon->GetSelection(nsISelectionController::SELECTION_NORMAL);

    if (!selection) return NS_OK;

  } else {

    selection = mWindow->GetSelection();

    if (!selection) return NS_OK;

    // Check if the node is inside a form control. Don't set aCanDrag to false

    // however, as we still want to allow the drag.

    nsCOMPtr<nsIContent> findFormNode = mSelectionTargetNode;

    nsIContent* findFormParent = findFormNode->GetParent();

    while (findFormParent) {

      nsCOMPtr<nsIFormControl> form(do_QueryInterface(findFormParent));

      if (form && !form->AllowDraggableChildren()) {

        return NS_OK;

      findFormParent = findFormParent->GetParent();

  // if set, serialize the content under this node

  nsCOMPtr<nsIContent> nodeToSerialize;

  BrowsingContext* bc = mWindow->GetBrowsingContext();

  const bool isChromeShell = bc && bc->IsChrome();

  // In chrome shells, only allow dragging inside editable areas.

  if (isChromeShell && !editingElement) {

    // This path should already be filtered out in

    // EventStateManager::DetermineDragTargetAndDefaultData.

    MOZ_ASSERT_UNREACHABLE("Shouldn't be generating drag data for chrome");

    return NS_OK;

  if (isChromeShell && textControlElement) {

    // Only use the selection if the target node is in the selection.

    if (!selection->ContainsNode(*mSelectionTargetNode, false, IgnoreErrors()))

      return NS_OK;

    selection.swap(*aSelection);

  } else {

    // In content shells, a number of checks are made below to determine

    // whether an image or a link is being dragged. If so, add additional

    // data to the data transfer. This is also done for chrome shells, but

    // only when in a non-textbox editor.

    bool haveSelectedContent = false;

    // possible parent link node

    nsCOMPtr<nsIContent> parentLink;

    nsCOMPtr<nsIContent> draggedNode;

      // only drag form elements by using the alt key,

      // otherwise buttons and select widgets are hard to use

      // Note that while <object> elements implement nsIFormControl, we should

      // really allow dragging them if they happen to be images.

      nsCOMPtr<nsIFormControl> form(do_QueryInterface(mTarget));

      if (form && !mIsAltKeyPressed &&

          form->ControlType() != FormControlType::Object) {

        *aCanDrag = false;

        return NS_OK;

      draggedNode = FindDragTarget(mTarget);

    nsCOMPtr<nsIImageLoadingContent> image;

    nsCOMPtr<nsIContent> selectedImageOrLinkNode;

    GetDraggableSelectionData(selection, mSelectionTargetNode,

                              getter_AddRefs(selectedImageOrLinkNode),

                              &haveSelectedContent);

    // either plain text or anchor text is selected

    if (haveSelectedContent) {

      selection.swap(*aSelection);

    } else if (selectedImageOrLinkNode) {

      // an image is selected

      image = do_QueryInterface(selectedImageOrLinkNode);

    } else {

      // nothing is selected -

//

      // look for draggable elements under the mouse

//

      // if the alt key is down, don't start a drag if we're in an

      // anchor because we want to do selection.

      parentLink = nsContentUtils::GetClosestLinkInFlatTree(draggedNode);

      if (parentLink && mIsAltKeyPressed) {

        *aCanDrag = false;

        return NS_OK;

      image = do_QueryInterface(draggedNode);

      // set for linked images, and links

      nsCOMPtr<nsIContent> linkNode;

      if (const auto* areaElem = HTMLAreaElement::FromNodeOrNull(draggedNode)) {

        // use the alt text (or, if missing, the href) as the title

        areaElem->GetAttr(nsGkAtoms::alt, mTitleString);

        if (mTitleString.IsEmpty()) {

          // this can be a relative link

          areaElem->GetAttr(nsGkAtoms::href, mTitleString);

        // gives an absolute link

        nsresult rv = GetAnchorURL(draggedNode, mUrlString);

        NS_ENSURE_SUCCESS(rv, rv);

        // we'll generate HTML like <a href="absurl">alt text</a>

        mIsAnchor = true;

        mHtmlString.AssignLiteral("<a href=\"");

        mHtmlString.Append(mUrlString);

        mHtmlString.AppendLiteral("\">");

        mHtmlString.Append(mTitleString);

        mHtmlString.AppendLiteral("</a>");

        dragNode = draggedNode;

      } else if (image) {

        // grab the href as the url, use alt text as the title of the

        // area if it's there.  the drag data is the image tag and src

        // attribute.

        nsCOMPtr<nsIURI> imageURI;

        image->GetCurrentURI(getter_AddRefs(imageURI));

        nsCOMPtr<Element> imageElement(do_QueryInterface(image));

        if (imageURI) {

          nsAutoCString spec;

          rv = imageURI->GetSpec(spec);

          NS_ENSURE_SUCCESS(rv, rv);

          nsIScriptSecurityManager* secMan =

              nsContentUtils::GetSecurityManager();

          rv = secMan->CheckLoadURIStrWithPrincipal(

              imageElement->NodePrincipal(), spec, 0);

          NS_ENSURE_SUCCESS(rv, rv);

          mIsAnchor = true;

          CopyUTF8toUTF16(spec, mUrlString);

        // XXXbz Shouldn't we use the "title" attr for title?  Using

        // "alt" seems very wrong....

        // XXXbz Also, what if this is an nsIImageLoadingContent

        // that's not an <html:img>?

        if (imageElement) {

          imageElement->GetAttr(nsGkAtoms::alt, mTitleString);

        if (mTitleString.IsEmpty()) {

          mTitleString = mUrlString;

        nsCOMPtr<imgIRequest> imgRequest;

        // grab the image data, and its request.

        nsCOMPtr<imgIContainer> img = nsContentUtils::GetImageFromContent(

            image, getter_AddRefs(imgRequest));

        if (imgRequest) {

          rv = GetImageData(img, imgRequest);

          NS_ENSURE_SUCCESS(rv, rv);

        if (parentLink) {

          // If we are dragging around an image in an anchor, then we

          // are dragging the entire anchor

          linkNode = parentLink;

          nodeToSerialize = linkNode;

        } else {

          nodeToSerialize = draggedNode;

        dragNode = nodeToSerialize;

      } else if (parentLink) {

        // parentLink will always be null if there's selected content

        linkNode = parentLink;

        nodeToSerialize = linkNode;

      } else if (!haveSelectedContent) {

        // nothing draggable

        return NS_OK;

      if (linkNode) {

        rv = GetAnchorURL(linkNode, mUrlString);

        NS_ENSURE_SUCCESS(rv, rv);

        mIsAnchor = true;

        dragNode = linkNode;

  if (nodeToSerialize || *aSelection) {

    mHtmlString.Truncate();

    mContextString.Truncate();

    mInfoString.Truncate();

    mTitleString.Truncate();

    nsCOMPtr<Document> doc = mWindow->GetDoc();

    NS_ENSURE_TRUE(doc, NS_ERROR_FAILURE);

    nsCOMPtr<nsIContentSecurityPolicy> csp = doc->GetCsp();

    if (csp) {

      NS_IF_ADDREF(*aCsp = csp);

    nsCOMPtr<nsICookieJarSettings> cookieJarSettings = doc->CookieJarSettings();

    if (cookieJarSettings) {

      NS_IF_ADDREF(*aCookieJarSettings = cookieJarSettings);

    // if we have selected text, use it in preference to the node

    nsCOMPtr<nsITransferable> transferable;

    if (*aSelection) {

      rv = nsCopySupport::GetTransferableForSelection(

          *aSelection, doc, getter_AddRefs(transferable));

    } else {

      rv = nsCopySupport::GetTransferableForNode(nodeToSerialize, doc,

                                                 getter_AddRefs(transferable));

    NS_ENSURE_SUCCESS(rv, rv);

    nsCOMPtr<nsISupports> supports;

    nsCOMPtr<nsISupportsString> data;

    rv = transferable->GetTransferData(kHTMLMime, getter_AddRefs(supports));

    data = do_QueryInterface(supports);

    if (NS_SUCCEEDED(rv)) {

      data->GetData(mHtmlString);

    rv = transferable->GetTransferData(kHTMLContext, getter_AddRefs(supports));

    data = do_QueryInterface(supports);

    if (NS_SUCCEEDED(rv)) {

      data->GetData(mContextString);

    rv = transferable->GetTransferData(kHTMLInfo, getter_AddRefs(supports));

    data = do_QueryInterface(supports);

    if (NS_SUCCEEDED(rv)) {

      data->GetData(mInfoString);

    rv = transferable->GetTransferData(kTextMime, getter_AddRefs(supports));

    data = do_QueryInterface(supports);

    NS_ENSURE_SUCCESS(rv, rv);  // require plain text at a minimum

    data->GetData(mTitleString);

  // default text value is the URL

  if (mTitleString.IsEmpty()) {

    mTitleString = mUrlString;

  // if we haven't constructed a html version, make one now

  if (mHtmlString.IsEmpty() && !mUrlString.IsEmpty())

    CreateLinkText(mUrlString, mTitleString, mHtmlString);

  // if there is no drag node, which will be the case for a selection, just

  // use the selection target node.

  rv = AddStringsToDataTransfer(

      dragNode ? dragNode : mSelectionTargetNode.get(), aDataTransfer);

  NS_ENSURE_SUCCESS(rv, rv);

  NS_IF_ADDREF(*aDragNode = dragNode);

  return NS_OK;

void DragDataProducer::AddString(DataTransfer* aDataTransfer,

                                 const nsAString& aFlavor,

                                 const nsAString& aData,

                                 nsIPrincipal* aPrincipal, bool aHidden) {

  RefPtr<nsVariantCC> variant = new nsVariantCC();

  variant->SetAsAString(aData);

  aDataTransfer->SetDataWithPrincipal(aFlavor, variant, 0, aPrincipal, aHidden);

nsresult DragDataProducer::AddStringsToDataTransfer(

    nsIContent* aDragNode, DataTransfer* aDataTransfer) {

  NS_ASSERTION(aDragNode, "adding strings for null node");

  // set all of the data to have the principal of the node where the data came

  // from

  nsIPrincipal* principal = aDragNode->NodePrincipal();

  // add a special flavor if we're an anchor to indicate that we have

  // a URL in the drag data

  if (!mUrlString.IsEmpty() && mIsAnchor) {

    nsAutoString dragData(mUrlString);

    dragData.Append('\n');

    // Remove leading and trailing newlines in the title and replace them with

    // space in remaining positions - they confuse PlacesUtils::unwrapNodes

    // that expects url\ntitle formatted data for x-moz-url.

    nsAutoString title(mTitleString);

    title.Trim("\r\n");

    title.ReplaceChar(u"\r\n", ' ');

    dragData += title;

    AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kURLMime), dragData,

              principal);

    AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kURLDataMime),

              mUrlString, principal);

    AddString(aDataTransfer,

              NS_LITERAL_STRING_FROM_CSTRING(kURLDescriptionMime), mTitleString,

              principal);

    AddString(aDataTransfer, u"text/uri-list"_ns, mUrlString, principal);

  // add a special flavor for the html context data

  if (!mContextString.IsEmpty())

    AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kHTMLContext),

              mContextString, principal);

  // add a special flavor if we have html info data

  if (!mInfoString.IsEmpty())

    AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kHTMLInfo),

              mInfoString, principal);

  // add the full html

  if (!mHtmlString.IsEmpty())

    AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kHTMLMime),

              mHtmlString, principal);

  // add the plain text. we use the url for text/plain data if an anchor is

  // being dragged, rather than the title text of the link or the alt text for

  // an anchor image.

  AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kTextMime),

            mIsAnchor ? mUrlString : mTitleString, principal);

  // add image data, if present. For now, all we're going to do with

  // this is turn it into a native data flavor, so indicate that with

  // a new flavor so as not to confuse anyone who is really registered

  // for image/gif or image/jpg.

  if (mImage) {

    RefPtr<nsVariantCC> variant = new nsVariantCC();

    variant->SetAsISupports(mImage);

    aDataTransfer->SetDataWithPrincipal(

        NS_LITERAL_STRING_FROM_CSTRING(kNativeImageMime), variant, 0,

        principal);

    // assume the image comes from a file, and add a file promise. We

    // register ourselves as a nsIFlavorDataProvider, and will use the

    // GetFlavorData callback to save the image to disk.

    nsCOMPtr<nsIFlavorDataProvider> dataProvider =

        new nsContentAreaDragDropDataProvider();

    if (dataProvider) {

      RefPtr<nsVariantCC> variant = new nsVariantCC();

      variant->SetAsISupports(dataProvider);

      aDataTransfer->SetDataWithPrincipal(

          NS_LITERAL_STRING_FROM_CSTRING(kFilePromiseMime), variant, 0,

          principal);

    AddString(aDataTransfer,

              NS_LITERAL_STRING_FROM_CSTRING(kFilePromiseURLMime),

              mImageSourceString, principal);

    AddString(aDataTransfer,

              NS_LITERAL_STRING_FROM_CSTRING(kFilePromiseDestFilename),

              mImageDestFileName, principal);

#if defined(XP_MACOSX)

    AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kImageRequestMime),

              mImageRequestMime, principal, /* aHidden= */ true);

#endif

    // if not an anchor, add the image url

    if (!mIsAnchor) {

      AddString(aDataTransfer, NS_LITERAL_STRING_FROM_CSTRING(kURLDataMime),

                mUrlString, principal);

      AddString(aDataTransfer, u"text/uri-list"_ns, mUrlString, principal);

  return NS_OK;

// note that this can return NS_OK, but a null out param (by design)

// static

nsresult DragDataProducer::GetDraggableSelectionData(

    Selection* inSelection, nsIContent* inRealTargetNode,

    nsIContent** outImageOrLinkNode, bool* outDragSelectedText) {

  NS_ENSURE_ARG(inSelection);

  NS_ENSURE_ARG(inRealTargetNode);

  NS_ENSURE_ARG_POINTER(outImageOrLinkNode);

  *outImageOrLinkNode = nullptr;

  *outDragSelectedText = false;

  if (!inSelection->IsCollapsed()) {

    if (inSelection->ContainsNode(*inRealTargetNode, false, IgnoreErrors())) {

      // track down the anchor node, if any, for the url

      nsINode* selectionStart = inSelection->GetAnchorNode();

      nsINode* selectionEnd = inSelection->GetFocusNode();

      // look for a selection around a single node, like an image.

      // in this case, drag the image, rather than a serialization of the HTML

      // XXX generalize this to other draggable element types?

      if (selectionStart == selectionEnd) {

        nsCOMPtr<nsIContent> selStartContent =

            nsIContent::FromNodeOrNull(selectionStart);

        if (selStartContent && selStartContent->HasChildNodes()) {

          // see if just one node is selected

          uint32_t anchorOffset = inSelection->AnchorOffset();

          uint32_t focusOffset = inSelection->FocusOffset();

          if (anchorOffset == focusOffset + 1 ||

              focusOffset == anchorOffset + 1) {

            uint32_t childOffset = std::min(anchorOffset, focusOffset);

            nsIContent* childContent =

                selStartContent->GetChildAt_Deprecated(childOffset);

            // if we find an image, we'll fall into the node-dragging code,

            // rather the the selection-dragging code

            if (nsContentUtils::IsDraggableImage(childContent)) {

              NS_ADDREF(*outImageOrLinkNode = childContent);

              return NS_OK;

      // indicate that a link or text is selected

      *outDragSelectedText = true;

  return NS_OK;