ui/gtk/input_method_context_impl_gtk.cc

// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "ui/gtk/input_method_context_impl_gtk.h"

#include <cstddef>

#include "base/strings/utf_string_conversions.h"
#include "ui/aura/window_tree_host.h"
#include "ui/base/ime/composition_text.h"
#include "ui/base/ime/linux/composition_text_util_pango.h"
#include "ui/base/ime/text_input_client.h"
#include "ui/base/ime/text_input_flags.h"
#include "ui/events/event.h"
#include "ui/events/event_utils.h"
#include "ui/gfx/geometry/dip_util.h"
#include "ui/gfx/geometry/rect_conversions.h"
#include "ui/gfx/native_widget_types.h"
#include "ui/gtk/gtk_compat.h"
#include "ui/gtk/gtk_ui.h"
#include "ui/gtk/gtk_ui_platform.h"
#include "ui/gtk/gtk_util.h"
#include "ui/linux/linux_ui.h"

namespace gtk {

namespace {

// Get IME KeyEvent's target window. Assumes root aura::Window is set to
// Event::target(), otherwise returns null.
GdkWindow* GetTargetWindow(const ui::KeyEvent& key_event) {
  if (!key_event.target()) {
    return nullptr;
  }

  aura::Window* window = static_cast<aura::Window*>(key_event.target());
  DCHECK(window) << "KeyEvent target window not set.";

  auto window_id = window->GetHost()->GetAcceleratedWidget();
  return GtkUi::GetPlatform()->GetGdkWindow(window_id);
}

int GetKeyEventProperty(const ui::KeyEvent& key_event,
                        const char* property_key) {
  auto* properties = key_event.properties();
  if (!properties) {
    return 0;
  }
  auto it = properties->find(property_key);
  DCHECK(it == properties->end() || it->second.size() == 1);
  return (it != properties->end()) ? it->second[0] : 0;
}

GdkModifierType GetGdkKeyEventState(const ui::KeyEvent& key_event) {
  // ui::KeyEvent uses a normalized modifier state which is not respected by
  // Gtk, so instead we obtain the original value from annotated properties.
  // See also x11_event_translation.cc where it is annotated.
  // cf) https://crbug.com/1086946#c11.
  const ui::Event::Properties* properties = key_event.properties();
  if (!properties) {
    return static_cast<GdkModifierType>(0);
  }
  auto it = properties->find(ui::kPropertyKeyboardState);
  if (it == properties->end()) {
    return static_cast<GdkModifierType>(0);
  }
  DCHECK_EQ(it->second.size(), 4u);
  // Stored in little endian.
  int result = 0;
  int bitshift = 0;
  for (uint8_t value : it->second) {
    result |= value << bitshift;
    bitshift += 8;
  }
  return static_cast<GdkModifierType>(result);
}

// Xkb Events store group attribute into XKeyEvent::state bit field, along with
// other state-related info, while GdkEventKey objects have separate fields for
// that purpose, they are ::state and ::group. This function is responsible for
// recomposing them into a single bit field value when translating GdkEventKey
// into XKeyEvent. This is similar to XkbBuildCoreState(), but assumes state is
// an uint rather than an uchar.
//
// More details:
// https://gitlab.freedesktop.org/xorg/proto/xorgproto/blob/master/include/X11/extensions/XKB.h#L372
int BuildXkbStateFromGdkEvent(unsigned int state, unsigned char group) {
  return state | ((group & 0x3) << 13);
}

// Translate IME ui::KeyEvent to a GdkEventKey.
GdkEventKey* GdkEventFromImeKeyEvent(const ui::KeyEvent& key_event) {
  DCHECK(!GtkCheckVersion(4));
  GdkEventType event_type = key_event.type() == ui::EventType::kKeyPressed
                                ? GdkKeyPress()
                                : GdkKeyRelease();
  auto event_time = key_event.time_stamp() - base::TimeTicks();
  int hw_code = GetKeyEventProperty(key_event, ui::kPropertyKeyboardHwKeyCode);
  int group = GetKeyEventProperty(key_event, ui::kPropertyKeyboardGroup);

  GdkKeymap* keymap = gdk_keymap_get_for_display(gdk_display_get_default());

  // Get keyval and state
  GdkModifierType state = GetGdkKeyEventState(key_event);
  guint keyval = GDK_KEY_VoidSymbol;
  GdkModifierType consumed;
  gdk_keymap_translate_keyboard_state(keymap, hw_code, state, group, &keyval,
                                      nullptr, nullptr, &consumed);
  gdk_keymap_add_virtual_modifiers(keymap, &state);
  DCHECK_NE(keyval, static_cast<guint>(GDK_KEY_VoidSymbol));

  // Build GdkEvent
  GdkEvent* gdk_event = gdk_event_new(event_type);
  GdkEventKey* gdk_event_key = reinterpret_cast<GdkEventKey*>(gdk_event);
  gdk_event_key->type = event_type;
  gdk_event_key->time = event_time.InMilliseconds();
  gdk_event_key->hardware_keycode = hw_code;
  gdk_event_key->keyval = keyval;
  gdk_event_key->state = BuildXkbStateFromGdkEvent(state, group);
  gdk_event_key->group = group;
  gdk_event_key->send_event = key_event.flags() & ui::EF_FINAL;
  gdk_event_key->is_modifier = state & GDK_MODIFIER_MASK;
  gdk_event_key->length = 0;
  gdk_event_key->string = nullptr;
  return gdk_event_key;
}

}  // namespace

InputMethodContextImplGtk::InputMethodContextImplGtk(
    ui::LinuxInputMethodContextDelegate* delegate)
    : delegate_(delegate) {
  CHECK(delegate_);

  gtk_context_ = TakeGObject(gtk_im_multicontext_new());

  static const char kAllowGtkWaylandIm[] = "allow-gtk-wayland-im";
  static const gchar* const kContextIdWayland = "wayland";
  static const gchar* kContextIdIbus = "ibus";
  const gchar* context_id = gtk_im_multicontext_get_context_id(
      GTK_IM_MULTICONTEXT(gtk_context_.get()));
  // switch to allow wayland IM module if it is picked.
  if (context_id) {
    if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
            kAllowGtkWaylandIm) &&
        (std::string(context_id) == kContextIdWayland)) {
      // The wayland IM module doesn't work at all because of our usage of dummy
      // window. So try using ibus module instead. Direct Wayland IM integration
      // is being tracked under crbug.com/40113488.
      // TODO(crbug.com/40801194) Remove this if dummy window is no longer used.
      VLOG(1) << "Overriding wayland IM context to ibus";
      gtk_im_multicontext_set_context_id(
          GTK_IM_MULTICONTEXT(gtk_context_.get()), kContextIdIbus);
    } else {
      // This is the case where a non-wayland IM module is picked as per the
      // user's configuration.
      VLOG(1) << "Using GTK IM context: " << context_id;
    }
  }
  gtk_simple_context_ = TakeGObject(gtk_im_context_simple_new());

  auto connect = [&](const char* detailed_signal, auto receiver) {
    for (auto context : {gtk_context_, gtk_simple_context_}) {
      // Unretained() is safe since InputMethodContextImplGtk will own the
      // ScopedGSignal.
      signals_.emplace_back(
          context, detailed_signal,
          base::BindRepeating(receiver, base::Unretained(this)));
    }
  };

  connect("commit", &InputMethodContextImplGtk::OnCommit);
  connect("preedit-changed", &InputMethodContextImplGtk::OnPreeditChanged);
  connect("preedit-end", &InputMethodContextImplGtk::OnPreeditEnd);
  connect("preedit-start", &InputMethodContextImplGtk::OnPreeditStart);
  // TODO(shuchen): Handle operations on surrounding text.
  // "delete-surrounding" and "retrieve-surrounding" signals should be
  // handled.

  if (GtkCheckVersion(4)) {
    auto* dummy_window = GetDummyWindow();
    gtk_im_context_set_client_widget(gtk_context_, dummy_window);
    gtk_im_context_set_client_widget(gtk_simple_context_, dummy_window);
  }
}

InputMethodContextImplGtk::~InputMethodContextImplGtk() = default;

// Overridden from ui::LinuxInputMethodContext
bool InputMethodContextImplGtk::DispatchKeyEvent(
    const ui::KeyEvent& key_event) {
  auto* gtk_context = GetIMContext();
  if (!gtk_context) {
    return false;
  }

  GdkEventKey* event = nullptr;
  if (!GtkCheckVersion(4)) {
    event = GdkEventFromImeKeyEvent(key_event);
    DCHECK(event);

    auto* window = GetTargetWindow(key_event);
    event->window = window;

    auto& last_set_client_window =
        gtk_context == gtk_context_
            ? last_set_client_window_for_gtk_context_
            : last_set_client_window_for_gtk_simple_comtext_;
    if (last_set_client_window != window) {
      gtk_im_context_set_client_window(gtk_context, window);
      last_set_client_window = window;
    }
  }

  // Convert the last known caret bounds relative to the screen coordinates
  // to a GdkRectangle relative to the client window.
  aura::Window* window = static_cast<aura::Window*>(key_event.target());
  gfx::Rect caret_bounds;
  if (gtk_context == gtk_context_) {
    caret_bounds = last_caret_bounds_;
  }
  // Use absolute coordinates on GTK4 since a dummy context window is provided
  // to GTK at position (0, 0).
  if (!GtkCheckVersion(4)) {
    caret_bounds -= window->GetBoundsInScreen().OffsetFromOrigin();
  }

  // Chrome's DIPs may be different from GTK's DIPs if
  // --force-device-scale-factor is used.
  caret_bounds = ScaleToRoundedRect(
      caret_bounds,
      GetDeviceScaleFactor() / gtk_widget_get_scale_factor(GetDummyWindow()));
  GdkRectangle gdk_rect = {caret_bounds.x(), caret_bounds.y(),
                           caret_bounds.width(), caret_bounds.height()};
  gtk_im_context_set_cursor_location(gtk_context, &gdk_rect);

  if (!GtkCheckVersion(4)) {
    const bool handled = GtkImContextFilterKeypress(gtk_context, event);
    gdk_event_free(reinterpret_cast<GdkEvent*>(event));
    return handled;
  }
  // In GTK4, clients can no longer create or modify events.  This makes using
  // the gtk_im_context_filter_keypress() API impossible.  Fortunately, an
  // alternative API called gtk_im_context_filter_key() was added for clients
  // that would have needed to construct their own event.  The parameters to
  // the new API are just a deconstructed version of a KeyEvent.
  bool press = key_event.type() == ui::EventType::kKeyPressed;
  auto* surface =
      gtk_native_get_surface(gtk_widget_get_native(GetDummyWindow()));
  auto* device = gdk_seat_get_keyboard(
      gdk_display_get_default_seat(gdk_display_get_default()));
  auto time = (key_event.time_stamp() - base::TimeTicks()).InMilliseconds();
  auto keycode = GetKeyEventProperty(key_event, ui::kPropertyKeyboardHwKeyCode);
  auto group = GetKeyEventProperty(key_event, ui::kPropertyKeyboardGroup);
  auto state = GetGdkKeyEventState(key_event);
  return gtk_im_context_filter_key(gtk_context, press, surface, device, time,
                                   keycode, state, group);
}

bool InputMethodContextImplGtk::IsPeekKeyEvent(const ui::KeyEvent& key_event) {
  // Peek events are only sent to make Lacros work with Wayland. Gtk does not
  // send peek events.
  return false;
}

void InputMethodContextImplGtk::Reset() {
  gtk_im_context_reset(gtk_context_);
  gtk_im_context_reset(gtk_simple_context_);

  // Some input methods may not honour the reset call.
  // Focusing out/in the to make sure it gets reset correctly.
  if (type_ != ui::TEXT_INPUT_TYPE_NONE) {
    gtk_im_context_focus_out(gtk_context_);
    gtk_im_context_focus_in(gtk_context_);
  }
}

void InputMethodContextImplGtk::UpdateFocus(
    bool has_client,
    ui::TextInputType old_type,
    const TextInputClientAttributes& new_client_attributes,
    ui::TextInputClient::FocusReason reason) {
  type_ = new_client_attributes.input_type;

  // We only focus when the focus is in a textfield.
  if (old_type != ui::TEXT_INPUT_TYPE_NONE) {
    gtk_im_context_focus_out(gtk_context_);
  }
  if (new_client_attributes.input_type != ui::TEXT_INPUT_TYPE_NONE) {
    gtk_im_context_focus_in(gtk_context_);
  }

  // simple context can be used in any textfield, including password box, and
  // even if the focused text input client's text input type is
  // ui::TEXT_INPUT_TYPE_NONE.
  if (has_client) {
    gtk_im_context_focus_in(gtk_simple_context_);
  } else {
    gtk_im_context_focus_out(gtk_simple_context_);
  }

  if (new_client_attributes.flags & ui::TEXT_INPUT_FLAG_VERTICAL) {
    g_object_set(gtk_context_, "input-hints", GTK_INPUT_HINT_VERTICAL_WRITING,
                 nullptr);
    g_object_set(gtk_simple_context_, "input-hints",
                 GTK_INPUT_HINT_VERTICAL_WRITING, nullptr);
  }
}

void InputMethodContextImplGtk::SetCursorLocation(const gfx::Rect& rect) {
  // Remember the caret bounds so that we can set the cursor location later.
  // gtk_im_context_set_cursor_location() takes the location relative to the
  // client window, which is unknown at this point.  So we'll call
  // gtk_im_context_set_cursor_location() later in DispatchKeyEvent() where
  // (and only where) we know the client window.
  last_caret_bounds_ = rect;
}

void InputMethodContextImplGtk::SetSurroundingText(
    const std::u16string& text,
    const gfx::Range& text_range,
    const gfx::Range& composition_range,
    const gfx::Range& selection_range) {}

// private:

// GtkIMContext event handlers.

void InputMethodContextImplGtk::OnCommit(GtkIMContext* context, gchar* text) {
  if (context != GetIMContext()) {
    return;
  }

  delegate_->OnCommit(base::UTF8ToUTF16(text));
}

void InputMethodContextImplGtk::OnPreeditChanged(GtkIMContext* context) {
  if (context != GetIMContext()) {
    return;
  }

  gchar* str = nullptr;
  PangoAttrList* attrs = nullptr;
  gint cursor_pos = 0;
  gtk_im_context_get_preedit_string(context, &str, &attrs, &cursor_pos);
  ui::CompositionText composition_text;
  ui::ExtractCompositionTextFromGtkPreedit(str, attrs, cursor_pos,
                                           &composition_text);
  g_free(str);
  pango_attr_list_unref(attrs);

  delegate_->OnPreeditChanged(composition_text);
}

void InputMethodContextImplGtk::OnPreeditEnd(GtkIMContext* context) {
  if (context != GetIMContext()) {
    return;
  }

  delegate_->OnPreeditEnd();
}

void InputMethodContextImplGtk::OnPreeditStart(GtkIMContext* context) {
  if (context != GetIMContext()) {
    return;
  }

  delegate_->OnPreeditStart();
}

ui::VirtualKeyboardController*
InputMethodContextImplGtk::GetVirtualKeyboardController() {
  return nullptr;
}

GtkIMContext* InputMethodContextImplGtk::GetIMContext() {
  switch (type_) {
    case ui::TEXT_INPUT_TYPE_NONE:
    case ui::TEXT_INPUT_TYPE_PASSWORD:
      return gtk_simple_context_;
    default:
      return gtk_context_;
  }
}

}  // namespace gtk