New InputMethod api for Views.

views/ime/input_method_gtk.cc

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "views/ime/input_method_gtk.h"
+
+#include <gdk/gdk.h>
+#include <gdk/gdkkeysyms.h>
+
+#include <algorithm>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "base/string_util.h"
+#include "base/third_party/icu/icu_utf.h"
+#include "base/utf_string_conversions.h"
+#include "ui/base/gtk/event_synthesis_gtk.h"
+#include "ui/base/gtk/gtk_im_context_util.h"
+#include "ui/base/keycodes/keyboard_codes.h"
+#include "ui/base/keycodes/keyboard_code_conversion_gtk.h"
+#include "views/events/event.h"
+#include "views/widget/widget.h"
+
+namespace views {
+
+InputMethodGtk::InputMethodGtk(internal::InputMethodDelegate* delegate)
+    : context_(NULL),
+      context_simple_(NULL),
+      widget_realize_id_(0),
+      widget_unrealize_id_(0),
+      context_focused_(false),
+      handling_key_event_(false),
+      composing_text_(false),
+      composition_changed_(false),
+      suppress_next_result_(false) {
+  set_delegate(delegate);
+}
+
+InputMethodGtk::~InputMethodGtk() {
+  if (widget()) {
+    GtkWidget* native_view = widget()->GetNativeView();
+    if (native_view) {
+      g_signal_handler_disconnect(native_view, widget_realize_id_);
+      g_signal_handler_disconnect(native_view, widget_unrealize_id_);
+    }
+  }
+  if (context_) {
+    g_object_unref(context_);
+    context_ = NULL;
+  }
+  if (context_simple_) {
+    g_object_unref(context_simple_);
+    context_simple_ = NULL;
+  }
+}
+
+void InputMethodGtk::Init(Widget* widget) {
+  InputMethodBase::Init(widget);
+
+  DCHECK(GTK_IS_WIDGET(widget->GetNativeView()));
+
+  widget_realize_id_ =
+      g_signal_connect(widget->GetNativeView(), "realize",
+                       G_CALLBACK(OnWidgetRealizeThunk), this);
+  widget_unrealize_id_ =
+      g_signal_connect(widget->GetNativeView(), "unrealize",
+                       G_CALLBACK(OnWidgetUnrealizeThunk), this);
+
+  context_ = gtk_im_multicontext_new();
+  context_simple_ = gtk_im_context_simple_new();
+
+  // context_ and context_simple_ share the same callback handlers.
+  // All data come from them are treated equally.
+  // context_ is for full input method support.
+  // context_simple_ is for supporting dead/compose keys when input method is
+  // disabled, eg. in password input box.
+  g_signal_connect(context_, "commit",
+                   G_CALLBACK(OnCommitThunk), this);
+  g_signal_connect(context_, "preedit_start",
+                   G_CALLBACK(OnPreeditStartThunk), this);
+  g_signal_connect(context_, "preedit_end",
+                   G_CALLBACK(OnPreeditEndThunk), this);
+  g_signal_connect(context_, "preedit_changed",
+                   G_CALLBACK(OnPreeditChangedThunk), this);
+
+  g_signal_connect(context_simple_, "commit",
+                   G_CALLBACK(OnCommitThunk), this);
+  g_signal_connect(context_simple_, "preedit_start",
+                   G_CALLBACK(OnPreeditStartThunk), this);
+  g_signal_connect(context_simple_, "preedit_end",
+                   G_CALLBACK(OnPreeditEndThunk), this);
+  g_signal_connect(context_simple_, "preedit_changed",
+                   G_CALLBACK(OnPreeditChangedThunk), this);
+
+  // Set client window if the widget is already realized.
+  OnWidgetRealize(widget->GetNativeView());
+}
+
+void InputMethodGtk::OnFocusIn() {
+  DCHECK(!widget_focused());
+  InputMethodBase::OnFocusIn();
+  UpdateContextFocusState();
+}
+
+void InputMethodGtk::OnFocusOut() {
+  DCHECK(widget_focused());
+  ConfirmCompositionText();
+  InputMethodBase::OnFocusOut();
+  UpdateContextFocusState();
+}
+
+void InputMethodGtk::DispatchKeyEvent(const KeyEvent& key) {
+  suppress_next_result_ = false;
+
+  // We should bypass |context_| and |context_simple_| only if there is no
+  // text input client is focused at all. Otherwise, we should always send the
+  // key event to either |context_| or |context_simple_| even if the text input
+  // type is ui::TEXT_INPUT_TYPE_NONE, to make sure we can get correct character
+  // result.
+  if (!GetTextInputClient()) {
+    DispatchKeyEventPostIME(key);
+    return;
+  }
+
+  handling_key_event_ = true;
+  composition_changed_ = false;
+  result_text_.clear();
+
+  GdkEvent* event = key.native_event();
+  DCHECK(!event || event->type == GDK_KEY_PRESS ||
+         event->type == GDK_KEY_RELEASE);
+
+  // If it's a fake key event, then we need to synthesis a GdkEventKey.
+  bool need_free_event = false;
+  if (!event) {
+    event = SynthesizeGdkEventKey(key);
+    need_free_event = true;
+  }
+
+  gboolean filtered = false;
+  if (context_focused_)
+    filtered = gtk_im_context_filter_keypress(context_, &event->key);
+  else
+    filtered = gtk_im_context_filter_keypress(context_simple_, &event->key);
+
+  handling_key_event_ = false;
+
+  View* old_focused_view = focused_view();
+  if (key.type() == ui::ET_KEY_PRESSED && filtered)
+    ProcessFilteredKeyPressEvent(key);
+
+  // In case the focus was changed by the key event.
+  if (old_focused_view != focused_view())
+    return;
+
+  if (HasInputMethodResult())
+    ProcessInputMethodResult(key, filtered);
+
+  // In case the focus was changed when sending input method results to the
+  // focused View.
+  if (old_focused_view != focused_view())
+    return;
+
+  if (key.type() == ui::ET_KEY_PRESSED && !filtered)
+    ProcessUnfilteredKeyPressEvent(key);
+  else if (key.type() == ui::ET_KEY_RELEASED)
+    DispatchKeyEventPostIME(key);
+
+  if (need_free_event)
+    gdk_event_free(event);
+}
+
+void InputMethodGtk::OnTextInputTypeChanged(View* view) {
+  if (IsViewFocused(view)) {
+    DCHECK(!composing_text_);
+    UpdateContextFocusState();
+  }
+}
+
+void InputMethodGtk::OnCaretBoundsChanged(View* view) {
+  gfx::Rect rect;
+  if (!IsViewFocused(view) || !GetCaretBoundsInWidget(&rect))
+    return;
+
+  GdkRectangle gdk_rect = rect.ToGdkRectangle();
+  gtk_im_context_set_cursor_location(context_, &gdk_rect);
+}
+
+void InputMethodGtk::CancelComposition(View* view) {
+  if (IsViewFocused(view))
+    ResetContext();
+}
+
+std::string InputMethodGtk::GetInputLocale() {
+  // Not supported.
+  return std::string("");
+}
+
+base::i18n::TextDirection InputMethodGtk::GetInputTextDirection() {
+  // Not supported.
+  return base::i18n::UNKNOWN_DIRECTION;
+}
+
+bool InputMethodGtk::IsActive() {
+  // We always need to send keyboard events to either |context_| or
+  // |context_simple_|, so just return true here.
+  return true;
+}
+
+void InputMethodGtk::FocusedViewWillChange() {
+  ConfirmCompositionText();
+}
+
+void InputMethodGtk::FocusedViewDidChange() {
+  UpdateContextFocusState();
+}
+
+void InputMethodGtk::ConfirmCompositionText() {
+  TextInputClient* client = GetTextInputClient();
+  if (client && client->HasCompositionText())
+    client->ConfirmCompositionText();
+
+  ResetContext();
+}
+
+void InputMethodGtk::ResetContext() {
+  if (!GetTextInputClient())
+    return;
+
+  DCHECK(widget_focused());
+  DCHECK(focused_view());
+  DCHECK(!handling_key_event_);
+
+  // To prevent any text from being committed when resetting the |context_|;
+  handling_key_event_ = true;
+  suppress_next_result_ = true;
+
+  gtk_im_context_reset(context_);
+  gtk_im_context_reset(context_simple_);
+
+  // Some input methods may not honour the reset call. Focusing out/in the
+  // |context_| to make sure it gets reset correctly.
+  if (context_focused_) {
+    gtk_im_context_focus_out(context_);
+    gtk_im_context_focus_in(context_);
+  }
+
+  composition_.Clear();
+  result_text_.clear();
+  handling_key_event_ = false;
+  composing_text_ = false;
+  composition_changed_ = false;
+}
+
+void InputMethodGtk::UpdateContextFocusState() {
+  bool old_context_focused = context_focused_;
+  // Use switch here in case we are going to add more text input types.
+  switch (GetTextInputType()) {
+    case ui::TEXT_INPUT_TYPE_NONE:
+    case ui::TEXT_INPUT_TYPE_PASSWORD:
+      context_focused_ = false;
+      break;
+    default:
+      context_focused_ = true;
+      break;
+  }
+
+  // We only focus in |context_| when the focus is in a normal textfield.
+  if (old_context_focused && !context_focused_)
+    gtk_im_context_focus_out(context_);
+  else if (!old_context_focused && context_focused_)
+    gtk_im_context_focus_in(context_);
+
+  // |context_simple_| 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 (GetTextInputClient())
+    gtk_im_context_focus_in(context_simple_);
+  else
+    gtk_im_context_focus_out(context_simple_);
+}
+
+void InputMethodGtk::ProcessFilteredKeyPressEvent(const KeyEvent& key) {
+  if (NeedInsertChar()) {
+    DispatchKeyEventPostIME(key);
+  } else {
+    KeyEvent key(ui::ET_KEY_PRESSED, ui::VKEY_PROCESSKEY, key.flags());
+    DispatchKeyEventPostIME(key);
+  }
+}
+
+void InputMethodGtk::ProcessUnfilteredKeyPressEvent(const KeyEvent& key) {
+  DispatchKeyEventPostIME(key);
+
+  // If a key event was not filtered by |context_| or |context_simple_|, then
+  // it means the key event didn't generate any result text. For some cases,
+  // the key event may still generate a valid character, eg. a control-key
+  // event (ctrl-a, return, tab, etc.). We need to send the character to the
+  // focused text input client by calling TextInputClient::InsertChar().
+  char16 ch = key.GetCharacter();
+  TextInputClient* client = GetTextInputClient();
+  if (ch && client)
+    client->InsertChar(ch, key.flags());
+}
+
+void InputMethodGtk::ProcessInputMethodResult(const KeyEvent& key,
+                                              bool filtered) {
+  TextInputClient* client = GetTextInputClient();
+  DCHECK(client);
+
+  if (result_text_.length()) {
+    if (filtered && NeedInsertChar()) {
+      for (string16::const_iterator i = result_text_.begin();
+           i != result_text_.end(); ++i) {
+        client->InsertChar(*i, key.flags());
+      }
+    } else {
+      client->InsertText(result_text_);
+      composing_text_ = false;
+    }
+  }
+
+  if (composition_changed_ && !IsTextInputTypeNone()) {
+    if (composition_.text.length()) {
+      composing_text_ = true;
+      client->SetCompositionText(composition_);
+    } else if (result_text_.empty()) {
+      client->ClearCompositionText();
+    }
+  }
+}
+
+bool InputMethodGtk::NeedInsertChar() const {
+  return IsTextInputTypeNone() ||
+      (!composing_text_ && result_text_.length() == 1);
+}
+
+bool InputMethodGtk::HasInputMethodResult() const {
+  return result_text_.length() || composition_changed_;
+}
+
+void InputMethodGtk::SendFakeProcessKeyEvent(bool pressed) const {
+  KeyEvent key(pressed ? ui::ET_KEY_PRESSED : ui::ET_KEY_RELEASED,
+               ui::VKEY_PROCESSKEY, 0);
+  DispatchKeyEventPostIME(key);
+}
+
+GdkEvent* InputMethodGtk::SynthesizeGdkEventKey(const KeyEvent& key) const {
+  guint keyval =
+      ui::GdkKeyCodeForWindowsKeyCode(key.key_code(), key.IsShiftDown());
+  guint state = 0;
+  if (key.IsShiftDown())
+    state |= GDK_SHIFT_MASK;
+  if (key.IsControlDown())
+    state |= GDK_CONTROL_MASK;
+  if (key.IsAltDown())
+    state |= GDK_MOD1_MASK;
+  if (key.IsCapsLockDown())
+    state |= GDK_LOCK_MASK;
+
+  DCHECK(widget()->GetNativeView()->window);
+  return ui::SynthesizeKeyEvent(widget()->GetNativeView()->window,
+                                key.type() == ui::ET_KEY_PRESSED,
+                                keyval, state);
+}
+
+void InputMethodGtk::OnCommit(GtkIMContext* context, gchar* text) {
+  if (suppress_next_result_) {
+    suppress_next_result_ = false;
+    return;
+  }
+
+  // We need to receive input method result even if the text input type is
+  // ui::TEXT_INPUT_TYPE_NONE, to make sure we can always send correct
+  // character for each key event to the focused text input client.
+  if (!GetTextInputClient())
+    return;
+
+  string16 utf16_text(UTF8ToUTF16(text));
+
+  // Append the text to the buffer, because commit signal might be fired
+  // multiple times when processing a key event.
+  result_text_.append(utf16_text);
+
+  // If we are not handling key event, do not bother sending text result if the
+  // focused text input client does not support text input.
+  if (!handling_key_event_ && !IsTextInputTypeNone()) {
+    SendFakeProcessKeyEvent(true);
+    GetTextInputClient()->InsertText(utf16_text);
+    SendFakeProcessKeyEvent(false);
+  }
+}
+
+void InputMethodGtk::OnPreeditStart(GtkIMContext* context) {
+  if (suppress_next_result_ || IsTextInputTypeNone())
+    return;
+
+  composing_text_ = true;
+}
+
+void InputMethodGtk::OnPreeditChanged(GtkIMContext* context) {
+  if (suppress_next_result_ || IsTextInputTypeNone())
+    return;
+
+  gchar* text = NULL;
+  PangoAttrList* attrs = NULL;
+  gint cursor_position = 0;
+  gtk_im_context_get_preedit_string(context, &text, &attrs, &cursor_position);
+
+  ui::ExtractCompositionTextFromGtkPreedit(text, attrs, cursor_position,
+                                           &composition_);
+  composition_changed_ = true;
+
+  g_free(text);
+  pango_attr_list_unref(attrs);
+
+  if (composition_.text.length())
+    composing_text_ = true;
+
+  if (!handling_key_event_ && !IsTextInputTypeNone()) {
+    SendFakeProcessKeyEvent(true);
+    GetTextInputClient()->SetCompositionText(composition_);
+    SendFakeProcessKeyEvent(false);
+  }
+}
+
+void InputMethodGtk::OnPreeditEnd(GtkIMContext* context) {
+  if (composition_.text.empty() || IsTextInputTypeNone())
+    return;
+
+  composition_changed_ = true;
+  composition_.Clear();
+
+  if (!handling_key_event_) {
+    TextInputClient* client = GetTextInputClient();
+    if (client && client->HasCompositionText())
+      client->ClearCompositionText();
+  }
+}
+
+void InputMethodGtk::OnWidgetRealize(GtkWidget* widget) {
+  // We should only set im context's client window once, because when setting
+  // client window, im context may destroy and recreate its internal states and
+  // objects.
+  if (widget->window) {
+    gtk_im_context_set_client_window(context_, widget->window);
+    gtk_im_context_set_client_window(context_simple_, widget->window);
+  }
+}
+
+void InputMethodGtk::OnWidgetUnrealize(GtkWidget* widget) {
+  gtk_im_context_set_client_window(context_, NULL);
+  gtk_im_context_set_client_window(context_simple_, NULL);
+}
+
+}  // namespace views