Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1425 insertions, 0 deletions

diff --git a/widget/gtk/nsClipboard.cpp b/widget/gtk/nsClipboard.cpp
new file mode 100644
index 0000000000..571b43f1cc
--- /dev/null
+++ b/widget/gtk/nsClipboard.cpp
@@ -0,0 +1,1425 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=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 "mozilla/ArrayUtils.h"
+
+#include "nsArrayUtils.h"
+#include "nsClipboard.h"
+#if defined(MOZ_X11)
+#  include "nsClipboardX11.h"
+#endif
+#if defined(MOZ_WAYLAND)
+#  include "nsClipboardWayland.h"
+#  include "nsWaylandDisplay.h"
+#endif
+#include "nsGtkUtils.h"
+#include "nsIURI.h"
+#include "nsIFile.h"
+#include "nsNetUtil.h"
+#include "nsContentUtils.h"
+#include "HeadlessClipboard.h"
+#include "nsSupportsPrimitives.h"
+#include "nsString.h"
+#include "nsReadableUtils.h"
+#include "nsPrimitiveHelpers.h"
+#include "nsImageToPixbuf.h"
+#include "nsStringStream.h"
+#include "nsIFileURL.h"
+#include "nsIObserverService.h"
+#include "mozilla/Services.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/GRefPtr.h"
+#include "mozilla/SchedulerGroup.h"
+#include "mozilla/StaticPrefs_widget.h"
+#include "mozilla/TimeStamp.h"
+#include "GRefPtr.h"
+#include "WidgetUtilsGtk.h"
+
+#include "imgIContainer.h"
+
+#include <gtk/gtk.h>
+#if defined(MOZ_X11)
+#  include <gtk/gtkx.h>
+#endif
+
+#include "mozilla/Encoding.h"
+
+using namespace mozilla;
+
+// Idle timeout for receiving selection and property notify events (microsec)
+// Right now it's set to 1 sec.
+const int kClipboardTimeout = 1000000;
+
+// Defines how many event loop iterations will be done without sleep.
+// We ususally get data in first 2-3 iterations unless some large object
+// (an image for instance) is transferred through clipboard.
+const int kClipboardFastIterationNum = 3;
+
+// We add this prefix to HTML markup, so that GetHTMLCharset can correctly
+// detect the HTML as UTF-8 encoded.
+static const char kHTMLMarkupPrefix[] =
+    R"(<meta http-equiv="content-type" content="text/html; charset=utf-8">)";
+
+static const char kURIListMime[] = "text/uri-list";
+
+ClipboardTargets nsRetrievalContext::sClipboardTargets;
+ClipboardTargets nsRetrievalContext::sPrimaryTargets;
+
+// Callback when someone asks us for the data
+static void clipboard_get_cb(GtkClipboard* aGtkClipboard,
+                             GtkSelectionData* aSelectionData, guint info,
+                             gpointer user_data);
+
+// Callback when someone asks us to clear a clipboard
+static void clipboard_clear_cb(GtkClipboard* aGtkClipboard, gpointer user_data);
+
+// Callback when owner of clipboard data is changed
+static void clipboard_owner_change_cb(GtkClipboard* aGtkClipboard,
+                                      GdkEventOwnerChange* aEvent,
+                                      gpointer aUserData);
+
+static bool GetHTMLCharset(Span<const char> aData, nsCString& str);
+
+static void SetTransferableData(nsITransferable* aTransferable,
+                                const nsACString& aFlavor,
+                                const char* aClipboardData,
+                                uint32_t aClipboardDataLength) {
+  LOGCLIP("SetTransferableData MIME %s\n", PromiseFlatCString(aFlavor).get());
+  nsCOMPtr<nsISupports> wrapper;
+  nsPrimitiveHelpers::CreatePrimitiveForData(
+      aFlavor, aClipboardData, aClipboardDataLength, getter_AddRefs(wrapper));
+  aTransferable->SetTransferData(PromiseFlatCString(aFlavor).get(), wrapper);
+}
+
+ClipboardTargets ClipboardTargets::Clone() {
+  ClipboardTargets ret;
+  ret.mCount = mCount;
+  if (mCount) {
+    ret.mTargets.reset(
+        reinterpret_cast<GdkAtom*>(g_malloc(sizeof(GdkAtom) * mCount)));
+    memcpy(ret.mTargets.get(), mTargets.get(), sizeof(GdkAtom) * mCount);
+  }
+  return ret;
+}
+
+void ClipboardTargets::Set(ClipboardTargets aTargets) {
+  mCount = aTargets.mCount;
+  mTargets = std::move(aTargets.mTargets);
+}
+
+void ClipboardData::SetData(Span<const uint8_t> aData) {
+  mData = nullptr;
+  mLength = aData.Length();
+  if (mLength) {
+    mData.reset(reinterpret_cast<char*>(g_malloc(sizeof(char) * mLength)));
+    memcpy(mData.get(), aData.data(), sizeof(char) * mLength);
+  }
+}
+
+void ClipboardData::SetText(Span<const char> aData) {
+  mData = nullptr;
+  mLength = aData.Length();
+  if (mLength) {
+    mData.reset(
+        reinterpret_cast<char*>(g_malloc(sizeof(char) * (mLength + 1))));
+    memcpy(mData.get(), aData.data(), sizeof(char) * mLength);
+    mData.get()[mLength] = '\0';
+  }
+}
+
+void ClipboardData::SetTargets(ClipboardTargets aTargets) {
+  mLength = aTargets.mCount;
+  mData.reset(reinterpret_cast<char*>(aTargets.mTargets.release()));
+}
+
+ClipboardTargets ClipboardData::ExtractTargets() {
+  GUniquePtr<GdkAtom> targets(reinterpret_cast<GdkAtom*>(mData.release()));
+  uint32_t length = std::exchange(mLength, 0);
+  return ClipboardTargets{std::move(targets), length};
+}
+
+GdkAtom GetSelectionAtom(int32_t aWhichClipboard) {
+  if (aWhichClipboard == nsIClipboard::kGlobalClipboard)
+    return GDK_SELECTION_CLIPBOARD;
+
+  return GDK_SELECTION_PRIMARY;
+}
+
+int GetGeckoClipboardType(GtkClipboard* aGtkClipboard) {
+  if (aGtkClipboard == gtk_clipboard_get(GDK_SELECTION_PRIMARY))
+    return nsClipboard::kSelectionClipboard;
+  else if (aGtkClipboard == gtk_clipboard_get(GDK_SELECTION_CLIPBOARD))
+    return nsClipboard::kGlobalClipboard;
+
+  return -1;  // THAT AIN'T NO CLIPBOARD I EVER HEARD OF
+}
+
+void nsRetrievalContext::ClearCachedTargetsClipboard(GtkClipboard* aClipboard,
+                                                     GdkEvent* aEvent,
+                                                     gpointer data) {
+  LOGCLIP("nsRetrievalContext::ClearCachedTargetsClipboard()");
+  sClipboardTargets.Clear();
+}
+
+void nsRetrievalContext::ClearCachedTargetsPrimary(GtkClipboard* aClipboard,
+                                                   GdkEvent* aEvent,
+                                                   gpointer data) {
+  LOGCLIP("nsRetrievalContext::ClearCachedTargetsPrimary()");
+  sPrimaryTargets.Clear();
+}
+
+ClipboardTargets nsRetrievalContext::GetTargets(int32_t aWhichClipboard) {
+  LOGCLIP("nsRetrievalContext::GetTargets(%s)\n",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+  ClipboardTargets& storedTargets =
+      (aWhichClipboard == nsClipboard::kSelectionClipboard) ? sPrimaryTargets
+                                                            : sClipboardTargets;
+  if (!storedTargets) {
+    LOGCLIP("  getting targets from system");
+    storedTargets.Set(GetTargetsImpl(aWhichClipboard));
+  } else {
+    LOGCLIP("  using cached targets");
+  }
+  return storedTargets.Clone();
+}
+
+nsRetrievalContext::~nsRetrievalContext() {
+  sClipboardTargets.Clear();
+  sPrimaryTargets.Clear();
+}
+
+nsClipboard::nsClipboard()
+    : nsBaseClipboard(mozilla::dom::ClipboardCapabilities(
+#ifdef MOZ_WAYLAND
+          widget::GdkIsWaylandDisplay()
+              ? widget::WaylandDisplayGet()->IsPrimarySelectionEnabled()
+              : true,
+#else
+          true, /* supportsSelectionClipboard */
+#endif
+          false /* supportsFindClipboard */,
+          false /* supportsSelectionCache */)) {
+  g_signal_connect(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD), "owner-change",
+                   G_CALLBACK(clipboard_owner_change_cb), this);
+  g_signal_connect(gtk_clipboard_get(GDK_SELECTION_PRIMARY), "owner-change",
+                   G_CALLBACK(clipboard_owner_change_cb), this);
+}
+
+nsClipboard::~nsClipboard() {
+  g_signal_handlers_disconnect_by_func(
+      gtk_clipboard_get(GDK_SELECTION_CLIPBOARD),
+      FuncToGpointer(clipboard_owner_change_cb), this);
+  g_signal_handlers_disconnect_by_func(
+      gtk_clipboard_get(GDK_SELECTION_PRIMARY),
+      FuncToGpointer(clipboard_owner_change_cb), this);
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(nsClipboard, nsBaseClipboard, nsIObserver)
+
+nsresult nsClipboard::Init(void) {
+#if defined(MOZ_X11)
+  if (widget::GdkIsX11Display()) {
+    mContext = new nsRetrievalContextX11();
+  }
+#endif
+#if defined(MOZ_WAYLAND)
+  if (widget::GdkIsWaylandDisplay()) {
+    mContext = new nsRetrievalContextWayland();
+  }
+#endif
+
+  nsCOMPtr<nsIObserverService> os = mozilla::services::GetObserverService();
+  if (os) {
+    os->AddObserver(this, "xpcom-shutdown", false);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsClipboard::Observe(nsISupports* aSubject, const char* aTopic,
+                     const char16_t* aData) {
+  // Save global clipboard content to CLIPBOARD_MANAGER.
+  // gtk_clipboard_store() can run an event loop, so call from a dedicated
+  // runnable.
+  return SchedulerGroup::Dispatch(
+      NS_NewRunnableFunction("gtk_clipboard_store()", []() {
+        LOGCLIP("nsClipboard storing clipboard content\n");
+        gtk_clipboard_store(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD));
+      }));
+}
+
+NS_IMETHODIMP
+nsClipboard::SetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  // See if we can short cut
+  if ((aWhichClipboard == kGlobalClipboard &&
+       aTransferable == mGlobalTransferable.get()) ||
+      (aWhichClipboard == kSelectionClipboard &&
+       aTransferable == mSelectionTransferable.get())) {
+    return NS_OK;
+  }
+
+  LOGCLIP("nsClipboard::SetNativeClipboardData (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  // List of suported targets
+  GtkTargetList* list = gtk_target_list_new(nullptr, 0);
+
+  // Get the types of supported flavors
+  nsTArray<nsCString> flavors;
+  nsresult rv = aTransferable->FlavorsTransferableCanExport(flavors);
+  if (NS_FAILED(rv)) {
+    LOGCLIP("    FlavorsTransferableCanExport failed!\n");
+    // Fall through.  |gtkTargets| will be null below.
+  }
+
+  // Add all the flavors to this widget's supported type.
+  bool imagesAdded = false;
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+    LOGCLIP("    processing target %s\n", flavorStr.get());
+
+    // Special case text/plain since we can handle all of the string types.
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      LOGCLIP("    adding TEXT targets\n");
+      gtk_target_list_add_text_targets(list, 0);
+      continue;
+    }
+
+    if (nsContentUtils::IsFlavorImage(flavorStr)) {
+      // Don't bother adding image targets twice
+      if (!imagesAdded) {
+        // accept any writable image type
+        LOGCLIP("    adding IMAGE targets\n");
+        gtk_target_list_add_image_targets(list, 0, TRUE);
+        imagesAdded = true;
+      }
+      continue;
+    }
+
+    if (flavorStr.EqualsLiteral(kFileMime)) {
+      LOGCLIP("    adding text/uri-list target\n");
+      GdkAtom atom = gdk_atom_intern(kURIListMime, FALSE);
+      gtk_target_list_add(list, atom, 0, 0);
+      continue;
+    }
+
+    // Add this to our list of valid targets
+    LOGCLIP("    adding OTHER target %s\n", flavorStr.get());
+    GdkAtom atom = gdk_atom_intern(flavorStr.get(), FALSE);
+    gtk_target_list_add(list, atom, 0, 0);
+  }
+
+  // Get GTK clipboard (CLIPBOARD or PRIMARY)
+  GtkClipboard* gtkClipboard =
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard));
+
+  gint numTargets = 0;
+  GtkTargetEntry* gtkTargets =
+      gtk_target_table_new_from_list(list, &numTargets);
+  if (!gtkTargets || numTargets == 0) {
+    LOGCLIP(
+        "    gtk_target_table_new_from_list() failed or empty list of "
+        "targets!\n");
+    // Clear references to the any old data and let GTK know that it is no
+    // longer available.
+    EmptyNativeClipboardData(aWhichClipboard);
+    return NS_ERROR_FAILURE;
+  }
+
+  ClearCachedTargets(aWhichClipboard);
+
+  // Set getcallback and request to store data after an application exit
+  if (gtk_clipboard_set_with_data(gtkClipboard, gtkTargets, numTargets,
+                                  clipboard_get_cb, clipboard_clear_cb, this)) {
+    // We managed to set-up the clipboard so update internal state
+    // We have to set it now because gtk_clipboard_set_with_data() calls
+    // clipboard_clear_cb() which reset our internal state
+    if (aWhichClipboard == kSelectionClipboard) {
+      mSelectionSequenceNumber++;
+      mSelectionTransferable = aTransferable;
+    } else {
+      mGlobalSequenceNumber++;
+      mGlobalTransferable = aTransferable;
+      gtk_clipboard_set_can_store(gtkClipboard, gtkTargets, numTargets);
+    }
+
+    rv = NS_OK;
+  } else {
+    LOGCLIP("    gtk_clipboard_set_with_data() failed!\n");
+    EmptyNativeClipboardData(aWhichClipboard);
+    rv = NS_ERROR_FAILURE;
+  }
+
+  gtk_target_table_free(gtkTargets, numTargets);
+  gtk_target_list_unref(list);
+
+  return rv;
+}
+
+mozilla::Result<int32_t, nsresult>
+nsClipboard::GetNativeClipboardSequenceNumber(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+  return aWhichClipboard == kSelectionClipboard ? mSelectionSequenceNumber
+                                                : mGlobalSequenceNumber;
+}
+
+static bool IsMIMEAtFlavourList(const nsTArray<nsCString>& aFlavourList,
+                                const char* aMime) {
+  for (const auto& flavorStr : aFlavourList) {
+    if (flavorStr.Equals(aMime)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+// When clipboard contains only images, X11/Gtk tries to convert them
+// to text when we request text instead of just fail to provide the data.
+// So if clipboard contains images only remove text MIME offer.
+bool nsClipboard::FilterImportedFlavors(int32_t aWhichClipboard,
+                                        nsTArray<nsCString>& aFlavors) {
+  LOGCLIP("nsClipboard::FilterImportedFlavors");
+
+  auto targets = mContext->GetTargets(aWhichClipboard);
+  if (!targets) {
+    LOGCLIP("    X11: no targes at clipboard (null), quit.\n");
+    return true;
+  }
+
+  for (const auto& atom : targets.AsSpan()) {
+    GUniquePtr<gchar> atom_name(gdk_atom_name(atom));
+    if (!atom_name) {
+      continue;
+    }
+    // Filter out system MIME types.
+    if (strcmp(atom_name.get(), "TARGETS") == 0 ||
+        strcmp(atom_name.get(), "TIMESTAMP") == 0 ||
+        strcmp(atom_name.get(), "SAVE_TARGETS") == 0 ||
+        strcmp(atom_name.get(), "MULTIPLE") == 0) {
+      continue;
+    }
+    // Filter out types which can't be converted to text.
+    if (strncmp(atom_name.get(), "image/", 6) == 0 ||
+        strncmp(atom_name.get(), "application/", 12) == 0 ||
+        strncmp(atom_name.get(), "audio/", 6) == 0 ||
+        strncmp(atom_name.get(), "video/", 6) == 0) {
+      continue;
+    }
+    // We have some other MIME type on clipboard which can be hopefully
+    // converted to text without any problem.
+    LOGCLIP("    X11: text types in clipboard, no need to filter them.\n");
+    return true;
+  }
+
+  // So make sure we offer only types we have at clipboard.
+  nsTArray<nsCString> clipboardFlavors;
+  for (const auto& atom : targets.AsSpan()) {
+    GUniquePtr<gchar> atom_name(gdk_atom_name(atom));
+    if (!atom_name) {
+      continue;
+    }
+    if (IsMIMEAtFlavourList(aFlavors, atom_name.get())) {
+      clipboardFlavors.AppendElement(nsCString(atom_name.get()));
+    }
+  }
+  aFlavors.SwapElements(clipboardFlavors);
+#ifdef MOZ_LOGGING
+  LOGCLIP("    X11: Flavors which match clipboard content:\n");
+  for (uint32_t i = 0; i < aFlavors.Length(); i++) {
+    LOGCLIP("    %s\n", aFlavors[i].get());
+  }
+#endif
+  return true;
+}
+
+static nsresult GetTransferableFlavors(nsITransferable* aTransferable,
+                                       nsTArray<nsCString>& aFlavors) {
+  if (!aTransferable) {
+    return NS_ERROR_FAILURE;
+  }
+  // Get a list of flavors this transferable can import
+  nsresult rv = aTransferable->FlavorsTransferableCanImport(aFlavors);
+  if (NS_FAILED(rv)) {
+    LOGCLIP("  FlavorsTransferableCanImport falied!\n");
+    return rv;
+  }
+#ifdef MOZ_LOGGING
+  LOGCLIP("  Flavors which can be imported:");
+  for (const auto& flavor : aFlavors) {
+    LOGCLIP("    %s", flavor.get());
+  }
+#endif
+  return NS_OK;
+}
+
+static bool TransferableSetFile(nsITransferable* aTransferable,
+                                const nsACString& aURIList) {
+  nsresult rv;
+  nsTArray<nsCString> uris = mozilla::widget::ParseTextURIList(aURIList);
+  if (!uris.IsEmpty()) {
+    nsCOMPtr<nsIURI> fileURI;
+    NS_NewURI(getter_AddRefs(fileURI), uris[0]);
+    if (nsCOMPtr<nsIFileURL> fileURL = do_QueryInterface(fileURI, &rv)) {
+      nsCOMPtr<nsIFile> file;
+      rv = fileURL->GetFile(getter_AddRefs(file));
+      if (NS_SUCCEEDED(rv)) {
+        aTransferable->SetTransferData(kFileMime, file);
+        LOGCLIP("  successfully set file to clipboard\n");
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+static bool TransferableSetHTML(nsITransferable* aTransferable,
+                                Span<const char> aData) {
+  nsLiteralCString mimeType(kHTMLMime);
+
+  // Convert text/html into our text format
+  nsAutoCString charset;
+  if (!GetHTMLCharset(aData, charset)) {
+    // Fall back to utf-8 in case html/data is missing kHTMLMarkupPrefix.
+    LOGCLIP("Failed to get html/text encoding, fall back to utf-8.\n");
+    charset.AssignLiteral("utf-8");
+  }
+
+  LOGCLIP("TransferableSetHTML: HTML detected charset %s", charset.get());
+  // app which use "text/html" to copy&paste
+  // get the decoder
+  auto encoding = Encoding::ForLabelNoReplacement(charset);
+  if (!encoding) {
+    LOGCLIP("TransferableSetHTML: get unicode decoder error (charset: %s)",
+            charset.get());
+    return false;
+  }
+
+  // According to spec html UTF-16BE/LE should be switched to UTF-8
+  // https://html.spec.whatwg.org/#determining-the-character-encoding:utf-16-encoding-2
+  if (encoding == UTF_16LE_ENCODING || encoding == UTF_16BE_ENCODING) {
+    encoding = UTF_8_ENCODING;
+  }
+
+  // Remove kHTMLMarkupPrefix again, it won't necessarily cause any
+  // issues, but might confuse other users.
+  const size_t prefixLen = ArrayLength(kHTMLMarkupPrefix) - 1;
+  if (aData.Length() >= prefixLen && nsDependentCSubstring(aData.To(prefixLen))
+                                         .EqualsLiteral(kHTMLMarkupPrefix)) {
+    aData = aData.From(prefixLen);
+  }
+
+  nsAutoString unicodeData;
+  auto [rv, enc] = encoding->Decode(AsBytes(aData), unicodeData);
+#if MOZ_LOGGING
+  if (enc != UTF_8_ENCODING &&
+      MOZ_LOG_TEST(gClipboardLog, mozilla::LogLevel::Debug)) {
+    nsCString decoderName;
+    enc->Name(decoderName);
+    LOGCLIP("TransferableSetHTML: expected UTF-8 decoder but got %s",
+            decoderName.get());
+  }
+#endif
+  if (NS_FAILED(rv)) {
+    LOGCLIP("TransferableSetHTML: failed to decode HTML");
+    return false;
+  }
+  SetTransferableData(aTransferable, mimeType,
+                      (const char*)unicodeData.BeginReading(),
+                      unicodeData.Length() * sizeof(char16_t));
+  return true;
+}
+
+NS_IMETHODIMP
+nsClipboard::GetNativeClipboardData(nsITransferable* aTransferable,
+                                    int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::GetNativeClipboardData (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  // TODO: Ensure we don't re-enter here.
+  if (!mContext) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nsTArray<nsCString> flavors;
+  nsresult rv = GetTransferableFlavors(aTransferable, flavors);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // Filter out MIME types on X11 to prevent unwanted conversions,
+  // see Bug 1611407
+  if (widget::GdkIsX11Display() &&
+      !FilterImportedFlavors(aWhichClipboard, flavors)) {
+    LOGCLIP("    Missing suitable clipboard data, quit.");
+    return NS_OK;
+  }
+
+  for (uint32_t i = 0; i < flavors.Length(); i++) {
+    nsCString& flavorStr = flavors[i];
+
+    if (flavorStr.EqualsLiteral(kJPEGImageMime) ||
+        flavorStr.EqualsLiteral(kJPGImageMime) ||
+        flavorStr.EqualsLiteral(kPNGImageMime) ||
+        flavorStr.EqualsLiteral(kGIFImageMime)) {
+      // Emulate support for image/jpg
+      if (flavorStr.EqualsLiteral(kJPGImageMime)) {
+        flavorStr.Assign(kJPEGImageMime);
+      }
+
+      LOGCLIP("    Getting image %s MIME clipboard data\n", flavorStr.get());
+
+      auto clipboardData =
+          mContext->GetClipboardData(flavorStr.get(), aWhichClipboard);
+      if (!clipboardData) {
+        LOGCLIP("    %s type is missing\n", flavorStr.get());
+        continue;
+      }
+
+      nsCOMPtr<nsIInputStream> byteStream;
+      NS_NewByteInputStream(getter_AddRefs(byteStream), clipboardData.AsSpan(),
+                            NS_ASSIGNMENT_COPY);
+      aTransferable->SetTransferData(flavorStr.get(), byteStream);
+      LOGCLIP("    got %s MIME data\n", flavorStr.get());
+      return NS_OK;
+    }
+
+    // Special case text/plain since we can convert any
+    // string into text/plain
+    if (flavorStr.EqualsLiteral(kTextMime)) {
+      LOGCLIP("    Getting text %s MIME clipboard data\n", flavorStr.get());
+
+      auto clipboardData = mContext->GetClipboardText(aWhichClipboard);
+      if (!clipboardData) {
+        LOGCLIP("    failed to get text data\n");
+        // If the type was text/plain and we couldn't get
+        // text off the clipboard, run the next loop
+        // iteration.
+        continue;
+      }
+
+      // Convert utf-8 into our text format.
+      NS_ConvertUTF8toUTF16 ucs2string(clipboardData.get());
+      SetTransferableData(aTransferable, flavorStr,
+                          (const char*)ucs2string.BeginReading(),
+                          ucs2string.Length() * 2);
+
+      LOGCLIP("    got text data, length %zd\n", ucs2string.Length());
+      return NS_OK;
+    }
+
+    if (flavorStr.EqualsLiteral(kFileMime)) {
+      LOGCLIP("    Getting %s file clipboard data\n", flavorStr.get());
+
+      auto clipboardData =
+          mContext->GetClipboardData(kURIListMime, aWhichClipboard);
+      if (!clipboardData) {
+        LOGCLIP("    text/uri-list type is missing\n");
+        continue;
+      }
+
+      nsDependentCSubstring fileName(clipboardData.AsSpan());
+      if (!TransferableSetFile(aTransferable, fileName)) {
+        continue;
+      }
+      return NS_OK;
+    }
+
+    LOGCLIP("    Getting %s MIME clipboard data\n", flavorStr.get());
+
+    auto clipboardData =
+        mContext->GetClipboardData(flavorStr.get(), aWhichClipboard);
+
+#ifdef MOZ_LOGGING
+    if (!clipboardData) {
+      LOGCLIP("    %s type is missing\n", flavorStr.get());
+    }
+#endif
+
+    if (clipboardData) {
+      LOGCLIP("    got %s mime type data.\n", flavorStr.get());
+
+      // Special case text/html since we can convert into UCS2
+      if (flavorStr.EqualsLiteral(kHTMLMime)) {
+        if (!TransferableSetHTML(aTransferable, clipboardData.AsSpan())) {
+          continue;
+        }
+      } else {
+        auto span = clipboardData.AsSpan();
+        SetTransferableData(aTransferable, flavorStr, span.data(),
+                            span.Length());
+      }
+      return NS_OK;
+    }
+  }
+
+  LOGCLIP("    failed to get clipboard content.\n");
+  return NS_OK;
+}
+
+enum DataType {
+  DATATYPE_IMAGE,
+  DATATYPE_FILE,
+  DATATYPE_HTML,
+  DATATYPE_RAW,
+};
+
+struct DataCallbackHandler {
+  RefPtr<nsITransferable> mTransferable;
+  nsBaseClipboard::GetDataCallback mDataCallback;
+  nsCString mMimeType;
+  DataType mDataType;
+
+  explicit DataCallbackHandler(RefPtr<nsITransferable> aTransferable,
+                               nsBaseClipboard::GetDataCallback&& aDataCallback,
+                               const char* aMimeType,
+                               DataType aDataType = DATATYPE_RAW)
+      : mTransferable(std::move(aTransferable)),
+        mDataCallback(std::move(aDataCallback)),
+        mMimeType(aMimeType),
+        mDataType(aDataType) {
+    MOZ_COUNT_CTOR(DataCallbackHandler);
+    LOGCLIP("DataCallbackHandler created [%p] MIME %s type %d", this,
+            mMimeType.get(), mDataType);
+  }
+  ~DataCallbackHandler() {
+    LOGCLIP("DataCallbackHandler deleted [%p]", this);
+    MOZ_COUNT_DTOR(DataCallbackHandler);
+  }
+};
+
+static void AsyncGetTextImpl(nsITransferable* aTransferable,
+                             int32_t aWhichClipboard,
+                             nsBaseClipboard::GetDataCallback&& aCallback) {
+  LOGCLIP("AsyncGetText() type '%s'",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+
+  gtk_clipboard_request_text(
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
+      [](GtkClipboard* aClipboard, const gchar* aText, gpointer aData) -> void {
+        UniquePtr<DataCallbackHandler> ref(
+            static_cast<DataCallbackHandler*>(aData));
+        LOGCLIP("AsyncGetText async handler of [%p]", aData);
+
+        size_t dataLength = aText ? strlen(aText) : 0;
+        if (dataLength <= 0) {
+          LOGCLIP("  quit, text is not available");
+          ref->mDataCallback(NS_OK);
+          return;
+        }
+
+        // Convert utf-8 into our unicode format.
+        NS_ConvertUTF8toUTF16 utf16string(aText, dataLength);
+        nsLiteralCString flavor(kTextMime);
+        SetTransferableData(ref->mTransferable, flavor,
+                            (const char*)utf16string.BeginReading(),
+                            utf16string.Length() * 2);
+        LOGCLIP("  text is set, length = %d", (int)dataLength);
+        ref->mDataCallback(NS_OK);
+      },
+      new DataCallbackHandler(aTransferable, std::move(aCallback), kTextMime));
+}
+
+static void AsyncGetDataImpl(nsITransferable* aTransferable,
+                             int32_t aWhichClipboard, const char* aMimeType,
+                             DataType aDataType,
+                             nsBaseClipboard::GetDataCallback&& aCallback) {
+  LOGCLIP("AsyncGetData() type '%s'",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+
+  const char* gtkMIMEType = nullptr;
+  switch (aDataType) {
+    case DATATYPE_FILE:
+      // Don't ask Gtk for application/x-moz-file
+      gtkMIMEType = kURIListMime;
+      break;
+    case DATATYPE_IMAGE:
+    case DATATYPE_HTML:
+    case DATATYPE_RAW:
+      gtkMIMEType = aMimeType;
+      break;
+  }
+
+  gtk_clipboard_request_contents(
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
+      gdk_atom_intern(gtkMIMEType, FALSE),
+      [](GtkClipboard* aClipboard, GtkSelectionData* aSelection,
+         gpointer aData) -> void {
+        UniquePtr<DataCallbackHandler> ref(
+            static_cast<DataCallbackHandler*>(aData));
+        LOGCLIP("AsyncGetData async handler [%p] MIME %s type %d", aData,
+                ref->mMimeType.get(), ref->mDataType);
+
+        int dataLength = gtk_selection_data_get_length(aSelection);
+        if (dataLength <= 0) {
+          ref->mDataCallback(NS_OK);
+          return;
+        }
+        const char* data = (const char*)gtk_selection_data_get_data(aSelection);
+        if (!data) {
+          ref->mDataCallback(NS_OK);
+          return;
+        }
+        switch (ref->mDataType) {
+          case DATATYPE_IMAGE: {
+            LOGCLIP("  set image clipboard data");
+            nsCOMPtr<nsIInputStream> byteStream;
+            NS_NewByteInputStream(getter_AddRefs(byteStream),
+                                  Span(data, dataLength), NS_ASSIGNMENT_COPY);
+            ref->mTransferable->SetTransferData(ref->mMimeType.get(),
+                                                byteStream);
+            break;
+          }
+          case DATATYPE_FILE: {
+            LOGCLIP("  set file clipboard data");
+            nsDependentCSubstring file(data, dataLength);
+            TransferableSetFile(ref->mTransferable, file);
+            break;
+          }
+          case DATATYPE_HTML: {
+            LOGCLIP("  html clipboard data");
+            Span dataSpan(data, dataLength);
+            TransferableSetHTML(ref->mTransferable, dataSpan);
+            break;
+          }
+          case DATATYPE_RAW: {
+            LOGCLIP("  raw clipboard data %s", ref->mMimeType.get());
+            SetTransferableData(ref->mTransferable, ref->mMimeType, data,
+                                dataLength);
+            break;
+          }
+        }
+        ref->mDataCallback(NS_OK);
+      },
+      new DataCallbackHandler(aTransferable, std::move(aCallback), aMimeType,
+                              aDataType));
+}
+
+static void AsyncGetDataFlavor(nsITransferable* aTransferable,
+                               int32_t aWhichClipboard, nsCString& aFlavorStr,
+                               nsBaseClipboard::GetDataCallback&& aCallback) {
+  if (aFlavorStr.EqualsLiteral(kJPEGImageMime) ||
+      aFlavorStr.EqualsLiteral(kJPGImageMime) ||
+      aFlavorStr.EqualsLiteral(kPNGImageMime) ||
+      aFlavorStr.EqualsLiteral(kGIFImageMime)) {
+    // Emulate support for image/jpg
+    if (aFlavorStr.EqualsLiteral(kJPGImageMime)) {
+      aFlavorStr.Assign(kJPEGImageMime);
+    }
+    LOGCLIP("  Getting image %s MIME clipboard data", aFlavorStr.get());
+    AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                     DATATYPE_IMAGE, std::move(aCallback));
+    return;
+  }
+  // Special case text/plain since we can convert any
+  // string into text/plain
+  if (aFlavorStr.EqualsLiteral(kTextMime)) {
+    LOGCLIP("  Getting unicode clipboard data");
+    AsyncGetTextImpl(aTransferable, aWhichClipboard, std::move(aCallback));
+    return;
+  }
+  if (aFlavorStr.EqualsLiteral(kFileMime)) {
+    LOGCLIP("  Getting file clipboard data\n");
+    AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                     DATATYPE_FILE, std::move(aCallback));
+    return;
+  }
+  if (aFlavorStr.EqualsLiteral(kHTMLMime)) {
+    LOGCLIP("  Getting HTML clipboard data");
+    AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                     DATATYPE_HTML, std::move(aCallback));
+    return;
+  }
+  LOGCLIP("  Getting raw %s MIME clipboard data\n", aFlavorStr.get());
+  AsyncGetDataImpl(aTransferable, aWhichClipboard, aFlavorStr.get(),
+                   DATATYPE_RAW, std::move(aCallback));
+}
+
+void nsClipboard::AsyncGetNativeClipboardData(nsITransferable* aTransferable,
+                                              int32_t aWhichClipboard,
+                                              GetDataCallback&& aCallback) {
+  MOZ_DIAGNOSTIC_ASSERT(aTransferable);
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::AsyncGetNativeClipboardData (%s)",
+          aWhichClipboard == nsClipboard::kSelectionClipboard ? "primary"
+                                                              : "clipboard");
+  nsTArray<nsCString> importedFlavors;
+  nsresult rv = GetTransferableFlavors(aTransferable, importedFlavors);
+  if (NS_FAILED(rv)) {
+    aCallback(rv);
+    return;
+  }
+
+  auto flavorsNum = importedFlavors.Length();
+  if (!flavorsNum) {
+    aCallback(NS_OK);
+    return;
+  }
+#ifdef MOZ_LOGGING
+  if (flavorsNum > 1) {
+    LOGCLIP("  Only first MIME type (%s) will be imported from clipboard!",
+            importedFlavors[0].get());
+  }
+#endif
+
+  // Filter out MIME types on X11 to prevent unwanted conversions,
+  // see Bug 1611407
+  if (widget::GdkIsX11Display()) {
+    AsyncHasNativeClipboardDataMatchingFlavors(
+        importedFlavors, aWhichClipboard,
+        [aWhichClipboard, transferable = nsCOMPtr{aTransferable},
+         callback = std::move(aCallback)](auto aResultOrError) mutable {
+          if (aResultOrError.isErr()) {
+            callback(aResultOrError.unwrapErr());
+            return;
+          }
+
+          nsTArray<nsCString> clipboardFlavors =
+              std::move(aResultOrError.unwrap());
+          if (!clipboardFlavors.Length()) {
+            LOGCLIP("  no flavors in clipboard, quit.");
+            callback(NS_OK);
+            return;
+          }
+
+          AsyncGetDataFlavor(transferable, aWhichClipboard, clipboardFlavors[0],
+                             std::move(callback));
+        });
+    return;
+  }
+
+  // Read clipboard directly on Wayland
+  AsyncGetDataFlavor(aTransferable, aWhichClipboard, importedFlavors[0],
+                     std::move(aCallback));
+}
+
+nsresult nsClipboard::EmptyNativeClipboardData(int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::EmptyNativeClipboardData (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  if (aWhichClipboard == kSelectionClipboard) {
+    if (mSelectionTransferable) {
+      gtk_clipboard_clear(gtk_clipboard_get(GDK_SELECTION_PRIMARY));
+      MOZ_ASSERT(!mSelectionTransferable);
+    }
+  } else {
+    if (mGlobalTransferable) {
+      gtk_clipboard_clear(gtk_clipboard_get(GDK_SELECTION_CLIPBOARD));
+      MOZ_ASSERT(!mGlobalTransferable);
+    }
+  }
+  ClearCachedTargets(aWhichClipboard);
+  return NS_OK;
+}
+
+void nsClipboard::ClearTransferable(int32_t aWhichClipboard) {
+  if (aWhichClipboard == kSelectionClipboard) {
+    mSelectionSequenceNumber++;
+    mSelectionTransferable = nullptr;
+  } else {
+    mGlobalSequenceNumber++;
+    mGlobalTransferable = nullptr;
+  }
+}
+
+static bool FlavorMatchesTarget(const nsACString& aFlavor, GdkAtom aTarget) {
+  GUniquePtr<gchar> atom_name(gdk_atom_name(aTarget));
+  if (!atom_name) {
+    return false;
+  }
+  if (aFlavor.Equals(atom_name.get())) {
+    LOGCLIP("    has %s\n", atom_name.get());
+    return true;
+  }
+  // X clipboard supports image/jpeg, but we want to emulate support
+  // for image/jpg as well
+  if (aFlavor.EqualsLiteral(kJPGImageMime) &&
+      !strcmp(atom_name.get(), kJPEGImageMime)) {
+    LOGCLIP("    has image/jpg\n");
+    return true;
+  }
+  // application/x-moz-file should be treated like text/uri-list
+  if (aFlavor.EqualsLiteral(kFileMime) &&
+      !strcmp(atom_name.get(), kURIListMime)) {
+    LOGCLIP("    has text/uri-list treating as application/x-moz-file");
+    return true;
+  }
+  return false;
+}
+
+mozilla::Result<bool, nsresult>
+nsClipboard::HasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::HasNativeClipboardDataMatchingFlavors (%s)\n",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  if (!mContext) {
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  auto targets = mContext->GetTargets(aWhichClipboard);
+  if (!targets) {
+    LOGCLIP("    no targes at clipboard (null)\n");
+    return false;
+  }
+
+#ifdef MOZ_LOGGING
+  if (LOGCLIP_ENABLED()) {
+    LOGCLIP("    Asking for content:\n");
+    for (auto& flavor : aFlavorList) {
+      LOGCLIP("        MIME %s\n", flavor.get());
+    }
+    LOGCLIP("    Clipboard content (target nums %zu):\n",
+            targets.AsSpan().Length());
+    for (const auto& target : targets.AsSpan()) {
+      GUniquePtr<gchar> atom_name(gdk_atom_name(target));
+      if (!atom_name) {
+        LOGCLIP("        failed to get MIME\n");
+        continue;
+      }
+      LOGCLIP("        MIME %s\n", atom_name.get());
+    }
+  }
+#endif
+
+  // Walk through the provided types and try to match it to a
+  // provided type.
+  for (auto& flavor : aFlavorList) {
+    // We special case text/plain here.
+    if (flavor.EqualsLiteral(kTextMime) &&
+        gtk_targets_include_text(targets.AsSpan().data(),
+                                 targets.AsSpan().Length())) {
+      LOGCLIP("    has kTextMime\n");
+      return true;
+    }
+    for (const auto& target : targets.AsSpan()) {
+      if (FlavorMatchesTarget(flavor, target)) {
+        return true;
+      }
+    }
+  }
+
+  LOGCLIP("    no targes at clipboard (bad match)\n");
+  return false;
+}
+
+struct TragetCallbackHandler {
+  TragetCallbackHandler(const nsTArray<nsCString>& aAcceptedFlavorList,
+                        nsBaseClipboard::HasMatchingFlavorsCallback&& aCallback)
+      : mAcceptedFlavorList(aAcceptedFlavorList.Clone()),
+        mCallback(std::move(aCallback)) {
+    LOGCLIP("TragetCallbackHandler(%p) created", this);
+  }
+  ~TragetCallbackHandler() {
+    LOGCLIP("TragetCallbackHandler(%p) deleted", this);
+  }
+  nsTArray<nsCString> mAcceptedFlavorList;
+  nsBaseClipboard::HasMatchingFlavorsCallback mCallback;
+};
+
+void nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors(
+    const nsTArray<nsCString>& aFlavorList, int32_t aWhichClipboard,
+    nsBaseClipboard::HasMatchingFlavorsCallback&& aCallback) {
+  MOZ_DIAGNOSTIC_ASSERT(
+      nsIClipboard::IsClipboardTypeSupported(aWhichClipboard));
+
+  LOGCLIP("nsClipboard::AsyncHasNativeClipboardDataMatchingFlavors (%s)",
+          aWhichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  gtk_clipboard_request_contents(
+      gtk_clipboard_get(GetSelectionAtom(aWhichClipboard)),
+      gdk_atom_intern("TARGETS", FALSE),
+      [](GtkClipboard* aClipboard, GtkSelectionData* aSelection,
+         gpointer aData) -> void {
+        LOGCLIP("gtk_clipboard_request_contents async handler (%p)", aData);
+        UniquePtr<TragetCallbackHandler> handler(
+            static_cast<TragetCallbackHandler*>(aData));
+
+        GdkAtom* targets = nullptr;
+        gint targetsNum = 0;
+        if (gtk_selection_data_get_length(aSelection) > 0) {
+          gtk_selection_data_get_targets(aSelection, &targets, &targetsNum);
+        }
+        nsTArray<nsCString> results;
+        if (targetsNum) {
+          for (auto& flavor : handler->mAcceptedFlavorList) {
+            LOGCLIP("  looking for %s", flavor.get());
+            if (flavor.EqualsLiteral(kTextMime) &&
+                gtk_targets_include_text(targets, targetsNum)) {
+              results.AppendElement(flavor);
+              LOGCLIP("    has kTextMime\n");
+              continue;
+            }
+            for (int i = 0; i < targetsNum; i++) {
+              if (FlavorMatchesTarget(flavor, targets[i])) {
+                results.AppendElement(flavor);
+              }
+            }
+          }
+        }
+        handler->mCallback(std::move(results));
+      },
+      new TragetCallbackHandler(aFlavorList, std::move(aCallback)));
+}
+
+nsITransferable* nsClipboard::GetTransferable(int32_t aWhichClipboard) {
+  nsITransferable* retval;
+
+  if (aWhichClipboard == kSelectionClipboard)
+    retval = mSelectionTransferable.get();
+  else
+    retval = mGlobalTransferable.get();
+
+  return retval;
+}
+
+void nsClipboard::SelectionGetEvent(GtkClipboard* aClipboard,
+                                    GtkSelectionData* aSelectionData) {
+  // Someone has asked us to hand them something.  The first thing
+  // that we want to do is see if that something includes text.  If
+  // it does, try to give it text/plain after converting it to
+  // utf-8.
+
+  int32_t whichClipboard;
+
+  // which clipboard?
+  GdkAtom selection = gtk_selection_data_get_selection(aSelectionData);
+  if (selection == GDK_SELECTION_PRIMARY)
+    whichClipboard = kSelectionClipboard;
+  else if (selection == GDK_SELECTION_CLIPBOARD)
+    whichClipboard = kGlobalClipboard;
+  else
+    return;  // THAT AIN'T NO CLIPBOARD I EVER HEARD OF
+
+  LOGCLIP("nsClipboard::SelectionGetEvent (%s)\n",
+          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+
+  nsCOMPtr<nsITransferable> trans = GetTransferable(whichClipboard);
+  if (!trans) {
+    // We have nothing to serve
+    LOGCLIP("nsClipboard::SelectionGetEvent() - %s clipboard is empty!\n",
+            whichClipboard == kSelectionClipboard ? "Primary" : "Clipboard");
+    return;
+  }
+
+  nsresult rv;
+  nsCOMPtr<nsISupports> item;
+
+  GdkAtom selectionTarget = gtk_selection_data_get_target(aSelectionData);
+  LOGCLIP("  selection target %s\n",
+          GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+
+  // Check to see if the selection data is some text type.
+  if (gtk_targets_include_text(&selectionTarget, 1)) {
+    LOGCLIP("  providing text/plain data\n");
+    // Try to convert our internal type into a text string.  Get
+    // the transferable for this clipboard and try to get the
+    // text/plain type for it.
+    rv = trans->GetTransferData("text/plain", getter_AddRefs(item));
+    if (NS_FAILED(rv) || !item) {
+      LOGCLIP("  GetTransferData() failed to get text/plain!\n");
+      return;
+    }
+
+    nsCOMPtr<nsISupportsString> wideString;
+    wideString = do_QueryInterface(item);
+    if (!wideString) return;
+
+    nsAutoString ucs2string;
+    wideString->GetData(ucs2string);
+    NS_ConvertUTF16toUTF8 utf8string(ucs2string);
+
+    LOGCLIP("  sent %zd bytes of utf-8 data\n", utf8string.Length());
+    if (selectionTarget == gdk_atom_intern("text/plain;charset=utf-8", FALSE)) {
+      LOGCLIP(
+          "  using gtk_selection_data_set for 'text/plain;charset=utf-8'\n");
+      // Bypass gtk_selection_data_set_text, which will convert \n to \r\n
+      // in some versions of GTK.
+      gtk_selection_data_set(aSelectionData, selectionTarget, 8,
+                             reinterpret_cast<const guchar*>(utf8string.get()),
+                             utf8string.Length());
+    } else {
+      gtk_selection_data_set_text(aSelectionData, utf8string.get(),
+                                  utf8string.Length());
+    }
+    return;
+  }
+
+  // Check to see if the selection data is an image type
+  if (gtk_targets_include_image(&selectionTarget, 1, TRUE)) {
+    LOGCLIP("  providing image data\n");
+    // Look through our transfer data for the image
+    static const char* const imageMimeTypes[] = {kNativeImageMime,
+                                                 kPNGImageMime, kJPEGImageMime,
+                                                 kJPGImageMime, kGIFImageMime};
+    nsCOMPtr<nsISupports> imageItem;
+    nsCOMPtr<imgIContainer> image;
+    for (uint32_t i = 0; i < ArrayLength(imageMimeTypes); i++) {
+      rv = trans->GetTransferData(imageMimeTypes[i], getter_AddRefs(imageItem));
+      if (NS_FAILED(rv)) {
+        LOGCLIP("    %s is missing at GetTransferData()\n", imageMimeTypes[i]);
+        continue;
+      }
+
+      image = do_QueryInterface(imageItem);
+      if (image) {
+        LOGCLIP("    %s is available at GetTransferData()\n",
+                imageMimeTypes[i]);
+        break;
+      }
+    }
+
+    if (!image) {  // Not getting an image for an image mime type!?
+      LOGCLIP("    Failed to get any image mime from GetTransferData()!\n");
+      return;
+    }
+
+    RefPtr<GdkPixbuf> pixbuf = nsImageToPixbuf::ImageToPixbuf(image);
+    if (!pixbuf) {
+      LOGCLIP("    nsImageToPixbuf::ImageToPixbuf() failed!\n");
+      return;
+    }
+
+    LOGCLIP("    Setting pixbuf image data as %s\n",
+            GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+    gtk_selection_data_set_pixbuf(aSelectionData, pixbuf);
+    return;
+  }
+
+  if (selectionTarget == gdk_atom_intern(kHTMLMime, FALSE)) {
+    LOGCLIP("  providing %s data\n", kHTMLMime);
+    rv = trans->GetTransferData(kHTMLMime, getter_AddRefs(item));
+    if (NS_FAILED(rv) || !item) {
+      LOGCLIP("  failed to get %s data by GetTransferData()!\n", kHTMLMime);
+      return;
+    }
+
+    nsCOMPtr<nsISupportsString> wideString;
+    wideString = do_QueryInterface(item);
+    if (!wideString) {
+      LOGCLIP("  failed to get wideString interface!");
+      return;
+    }
+
+    nsAutoString ucs2string;
+    wideString->GetData(ucs2string);
+
+    nsAutoCString html;
+    // Add the prefix so the encoding is correctly detected.
+    html.AppendLiteral(kHTMLMarkupPrefix);
+    AppendUTF16toUTF8(ucs2string, html);
+
+    LOGCLIP("  Setting %zd bytes of %s data\n", html.Length(),
+            GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+    gtk_selection_data_set(aSelectionData, selectionTarget, 8,
+                           (const guchar*)html.get(), html.Length());
+    return;
+  }
+
+  // We put kFileMime onto the clipboard as kURIListMime.
+  if (selectionTarget == gdk_atom_intern(kURIListMime, FALSE)) {
+    LOGCLIP("  providing %s data\n", kURIListMime);
+    rv = trans->GetTransferData(kFileMime, getter_AddRefs(item));
+    if (NS_FAILED(rv) || !item) {
+      LOGCLIP("  failed to get %s data by GetTransferData()!\n", kFileMime);
+      return;
+    }
+
+    nsCOMPtr<nsIFile> file = do_QueryInterface(item);
+    if (!file) {
+      LOGCLIP("  failed to get nsIFile interface!");
+      return;
+    }
+
+    nsCOMPtr<nsIURI> fileURI;
+    rv = NS_NewFileURI(getter_AddRefs(fileURI), file);
+    if (NS_FAILED(rv)) {
+      LOGCLIP("  failed to get fileURI\n");
+      return;
+    }
+
+    nsAutoCString uri;
+    if (NS_FAILED(fileURI->GetSpec(uri))) {
+      LOGCLIP("  failed to get fileURI spec\n");
+      return;
+    }
+
+    LOGCLIP("  Setting %zd bytes of data\n", uri.Length());
+    gtk_selection_data_set(aSelectionData, selectionTarget, 8,
+                           (const guchar*)uri.get(), uri.Length());
+    return;
+  }
+
+  LOGCLIP("  Try if we have anything at GetTransferData() for %s\n",
+          GUniquePtr<gchar>(gdk_atom_name(selectionTarget)).get());
+
+  // Try to match up the selection data target to something our
+  // transferable provides.
+  GUniquePtr<gchar> target_name(gdk_atom_name(selectionTarget));
+  if (!target_name) {
+    LOGCLIP("  Failed to get target name!\n");
+    return;
+  }
+
+  rv = trans->GetTransferData(target_name.get(), getter_AddRefs(item));
+  // nothing found?
+  if (NS_FAILED(rv) || !item) {
+    LOGCLIP("  Failed to get anything from GetTransferData()!\n");
+    return;
+  }
+
+  void* primitive_data = nullptr;
+  uint32_t dataLen = 0;
+  nsPrimitiveHelpers::CreateDataFromPrimitive(
+      nsDependentCString(target_name.get()), item, &primitive_data, &dataLen);
+  if (!primitive_data) {
+    LOGCLIP("  Failed to get primitive data!\n");
+    return;
+  }
+
+  LOGCLIP("  Setting %s as a primitive data type, %d bytes\n",
+          target_name.get(), dataLen);
+  gtk_selection_data_set(aSelectionData, selectionTarget,
+                         8, /* 8 bits in a unit */
+                         (const guchar*)primitive_data, dataLen);
+  free(primitive_data);
+}
+
+void nsClipboard::ClearCachedTargets(int32_t aWhichClipboard) {
+  if (aWhichClipboard == kSelectionClipboard) {
+    nsRetrievalContext::ClearCachedTargetsPrimary(nullptr, nullptr, nullptr);
+  } else {
+    nsRetrievalContext::ClearCachedTargetsClipboard(nullptr, nullptr, nullptr);
+  }
+}
+
+void nsClipboard::SelectionClearEvent(GtkClipboard* aGtkClipboard) {
+  int32_t whichClipboard = GetGeckoClipboardType(aGtkClipboard);
+  if (whichClipboard < 0) {
+    return;
+  }
+  LOGCLIP("nsClipboard::SelectionClearEvent (%s)\n",
+          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  ClearCachedTargets(whichClipboard);
+  ClearTransferable(whichClipboard);
+  ClearClipboardCache(whichClipboard);
+}
+
+void nsClipboard::OwnerChangedEvent(GtkClipboard* aGtkClipboard,
+                                    GdkEventOwnerChange* aEvent) {
+  int32_t whichClipboard = GetGeckoClipboardType(aGtkClipboard);
+  if (whichClipboard < 0) {
+    return;
+  }
+  LOGCLIP("nsClipboard::OwnerChangedEvent (%s)\n",
+          whichClipboard == kSelectionClipboard ? "primary" : "clipboard");
+  GtkWidget* gtkWidget = [aEvent]() -> GtkWidget* {
+    if (!aEvent->owner) {
+      return nullptr;
+    }
+    gpointer user_data = nullptr;
+    gdk_window_get_user_data(aEvent->owner, &user_data);
+    return GTK_WIDGET(user_data);
+  }();
+  // If we can get GtkWidget from the current clipboard owner, this
+  // owner-changed event must be triggered by ourself via calling
+  // gtk_clipboard_set_with_data, the sequence number should already be handled.
+  if (!gtkWidget) {
+    if (whichClipboard == kSelectionClipboard) {
+      mSelectionSequenceNumber++;
+    } else {
+      mGlobalSequenceNumber++;
+    }
+  }
+
+  ClearCachedTargets(whichClipboard);
+}
+
+void clipboard_get_cb(GtkClipboard* aGtkClipboard,
+                      GtkSelectionData* aSelectionData, guint info,
+                      gpointer user_data) {
+  LOGCLIP("clipboard_get_cb() callback\n");
+  nsClipboard* clipboard = static_cast<nsClipboard*>(user_data);
+  clipboard->SelectionGetEvent(aGtkClipboard, aSelectionData);
+}
+
+void clipboard_clear_cb(GtkClipboard* aGtkClipboard, gpointer user_data) {
+  LOGCLIP("clipboard_clear_cb() callback\n");
+  nsClipboard* clipboard = static_cast<nsClipboard*>(user_data);
+  clipboard->SelectionClearEvent(aGtkClipboard);
+}
+
+void clipboard_owner_change_cb(GtkClipboard* aGtkClipboard,
+                               GdkEventOwnerChange* aEvent,
+                               gpointer aUserData) {
+  LOGCLIP("clipboard_owner_change_cb() callback\n");
+  nsClipboard* clipboard = static_cast<nsClipboard*>(aUserData);
+  clipboard->OwnerChangedEvent(aGtkClipboard, aEvent);
+}
+
+/*
+ * This function extracts the encoding label from the subset of HTML internal
+ * encoding declaration syntax that uses the old long form with double quotes
+ * and without spaces around the equals sign between the "content" attribute
+ * name and the attribute value.
+ *
+ * This was added for the sake of an ancient version of StarOffice
+ * in the pre-UTF-8 era in bug 123389. It is unclear if supporting
+ * non-UTF-8 encodings is still necessary and if this function
+ * still needs to exist.
+ *
+ * As of December 2022, both Gecko and LibreOffice emit an UTF-8
+ * declaration that this function successfully extracts "UTF-8" from,
+ * but that's also the default that we fall back on if this function
+ * fails to extract a label.
+ */
+bool GetHTMLCharset(Span<const char> aData, nsCString& aFoundCharset) {
+  // Assume ASCII first to find "charset" info
+  const nsDependentCSubstring htmlStr(aData);
+  nsACString::const_iterator start, end;
+  htmlStr.BeginReading(start);
+  htmlStr.EndReading(end);
+  nsACString::const_iterator valueStart(start), valueEnd(start);
+
+  if (CaseInsensitiveFindInReadable("CONTENT=\"text/html;"_ns, start, end)) {
+    start = end;
+    htmlStr.EndReading(end);
+
+    if (CaseInsensitiveFindInReadable("charset="_ns, start, end)) {
+      valueStart = end;
+      start = end;
+      htmlStr.EndReading(end);
+
+      if (FindCharInReadable('"', start, end)) valueEnd = start;
+    }
+  }
+  // find "charset" in HTML
+  if (valueStart != valueEnd) {
+    aFoundCharset = Substring(valueStart, valueEnd);
+    ToUpperCase(aFoundCharset);
+    return true;
+  }
+  return false;
+}