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// Copyright 2010-2012, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//     * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#include "unix/ibus/mozc_engine.h"

#include <ibus.h>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <limits>
#include <map>
#include <sstream>
#include <string>

#include "base/base.h"
#include "base/const.h"
#include "base/protobuf/descriptor.h"
#include "base/protobuf/message.h"
#include "base/singleton.h"
#include "base/util.h"
#include "config/config.pb.h"
#include "session/commands.pb.h"
#include "session/ime_switch_util.h"
#include "unix/ibus/config_util.h"
#include "unix/ibus/engine_registrar.h"
#include "unix/ibus/ibus_candidate_window_handler.h"
#include "unix/ibus/key_event_handler.h"
#include "unix/ibus/message_translator.h"
#include "unix/ibus/mozc_engine_property.h"
#include "unix/ibus/path_util.h"
#include "unix/ibus/preedit_handler.h"
#include "unix/ibus/property_handler.h"

#ifdef OS_CHROMEOS
// use standalone (in-process) session
#include "unix/ibus/client.h"
#else
// use server/client session
#include "client/client.h"
#endif

#ifdef ENABLE_GTK_RENDERER
#include "renderer/renderer_client.h"
#include "unix/ibus/gtk_candidate_window_handler.h"
#endif  // ENABLE_GTK_RENDERER

#ifdef ENABLE_GTK_RENDERER
DEFINE_bool(use_mozc_candidate_window, true,
            "The engine uses GTK+ native candidate window service.");
#endif  // ENABLE_GTK_RENDERER

namespace {

// A key which associates an IBusProperty object with MozcEngineProperty.
const char kGObjectDataKey[] = "ibus-mozc-aux-data";
// An ID for a candidate which is not associated with a text.
const int32 kBadCandidateId = -1;
// The ibus-memconf section name in which we're interested.
const char kMozcSectionName[] = "engine/Mozc";

#ifdef ENABLE_GTK_RENDERER
const char kMozcPanelSectionName[] = "panel";
#endif  // ENABLE_GTK_RENDERER
// Icon path for MozcTool
const char kMozcToolIconPath[] = "tool.png";

// Default UI locale
const char kMozcDefaultUILocale[] = "en_US.UTF-8";

// for every 5 minutes, call SyncData
const uint64 kSyncDataInterval = 5 * 60;

#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
// Following constants are used to emulate ibus_engine_delete_surrounding_text

// Backspace key code
const guint kBackSpaceKeyCode = 14;

// Left shift key code
const guint kShiftLeftKeyCode = 42;
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT

#ifdef OS_CHROMEOS
// IBus config names for Mozc.
// This list must match the preference names of ibus-mozc for Chrome OS.
// Check the following file in the chrome repository when you modify this list.
// chrome/browser/chromeos/language_preferences.cc
const gchar* kMozcConfigNames[] = {
  "incognito_mode",
  "use_auto_ime_turn_off",
  "use_date_conversion",
  "use_single_kanji_conversion",
  "use_symbol_conversion",
  "use_number_conversion",
  "use_history_suggest",
  "use_dictionary_suggest",
  "use_realtime_conversion",
  "preedit_method",
  "session_keymap",
  "punctuation_method",
  "symbol_method",
  "space_character_form",
  "history_learning_level",
  //  "selection_shortcut",  // currently not supported
  "shift_key_mode_switch",
  "numpad_character_form",
  "suggestions_size",
};
#endif  // OS_CHROMEOS

#if IBUS_CHECK_VERSION(1, 4, 0)
#define USE_IBUS_ENGINE_GET_SURROUNDING_TEXT
#endif  // libibus (>= 1.4.0)

#ifndef OS_CHROMEOS
const char *kUILocaleEnvNames[] = {
  "LC_ALL",
  "LC_MESSAGES",
  "LANG",
};

string GetMessageLocale() {
  for (size_t i = 0; i < arraysize(kUILocaleEnvNames); ++i) {
    const char *env_ptr = ::getenv(kUILocaleEnvNames[i]);
    if (env_ptr == NULL || env_ptr[0] == '\0') {
      continue;
    }
    return env_ptr;
  }
  return kMozcDefaultUILocale;
}
#endif  // !OS_CHROMEOS

struct IBusMozcEngineClass {
  IBusEngineClass parent;
};

struct IBusMozcEngine {
  IBusEngine parent;
  mozc::ibus::MozcEngine *engine;
};

IBusEngineClass *g_parent_class = NULL;

GObject *MozcEngineClassConstructor(
    GType type,
    guint n_construct_properties,
    GObjectConstructParam *construct_properties) {
  return G_OBJECT_CLASS(g_parent_class)->constructor(type,
                                                     n_construct_properties,
                                                     construct_properties);
}

void MozcEngineClassDestroy(IBusObject *engine) {
  IBUS_OBJECT_CLASS(g_parent_class)->destroy(engine);
}

void MozcEngineClassInit(gpointer klass, gpointer class_data) {
  IBusEngineClass *engine_class = IBUS_ENGINE_CLASS(klass);

  VLOG(2) << "MozcEngineClassInit is called";
  mozc::ibus::EngineRegistrar::Register(
      mozc::Singleton<mozc::ibus::MozcEngine>::get(), engine_class);

  g_parent_class = reinterpret_cast<IBusEngineClass*>(
      g_type_class_peek_parent(klass));

  GObjectClass *object_class = G_OBJECT_CLASS(klass);
  object_class->constructor = MozcEngineClassConstructor;
  IBusObjectClass *ibus_object_class = IBUS_OBJECT_CLASS(klass);
  ibus_object_class->destroy = MozcEngineClassDestroy;
}

void MozcEngineInstanceInit(GTypeInstance *instance, gpointer klass) {
  IBusMozcEngine *engine = reinterpret_cast<IBusMozcEngine*>(instance);
  engine->engine = mozc::Singleton<mozc::ibus::MozcEngine>::get();
}

}  // namespace

namespace mozc {
namespace {

#if defined(USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT) ||  \
    defined(USE_IBUS_ENGINE_GET_SURROUNDING_TEXT)

// This function calculates |from| - |to| and stores the result
// into |delta| with checking integer overflow.
// Returns true when neither |abs(delta)| nor |-delta| does not cause
// integer overflow, that is, |delta| is in a safe range.
// Returns false otherwise.
bool GetSafeDelta(guint from, guint to, int32 *delta) {
  DCHECK(delta);

  COMPILE_ASSERT(sizeof(int64) > sizeof(guint), int64_guint_check);
  COMPILE_ASSERT(sizeof(int64) == sizeof(llabs(0)), int64_llabs_check);
  const int64 kInt32AbsMax =
      llabs(static_cast<int64>(numeric_limits<int32>::max()));
  const int64 kInt32AbsMin =
      llabs(static_cast<int64>(numeric_limits<int32>::min()));
  const int64 kInt32SafeAbsMax =
      min(kInt32AbsMax, kInt32AbsMin);

  const int64 diff = static_cast<int64>(from) - static_cast<int64>(to);
  if (llabs(diff) > kInt32SafeAbsMax) {
    return false;
  }

  *delta = static_cast<int32>(diff);
  return true;
}

#endif  // USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT ||
        // USE_IBUS_ENGINE_GET_SURROUNDING_TEXT
}  // namespace

namespace ibus {

namespace {
client::ClientInterface *CreateClient() {
#ifdef OS_CHROMEOS
  return new ibus::Client();
#else
  return client::ClientFactory::NewClient();
#endif
}

MessageTranslatorInterface *CreateTranslator() {
// It is OK not to translate messages in our side on ChromeOS, where built-in
// translation mechanism exists.
#ifdef OS_CHROMEOS
  return new NullMessageTranslator();
#else
  return new LocaleBasedMessageTranslator(GetMessageLocale());
#endif
}

}  // namespace

MozcEngine::MozcEngine()
    : last_sync_time_(Util::GetTime()),
      key_event_handler_(new KeyEventHandler),
      client_(CreateClient()),
#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
      ignore_reset_for_deletion_range_workaround_(false),
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
      property_handler_(new PropertyHandler(CreateTranslator(),
                                            client_.get())),
      preedit_handler_(new PreeditHandler()),
#ifdef ENABLE_GTK_RENDERER
      gtk_candidate_window_handler_(new GtkCandidateWindowHandler(
          new renderer::RendererClient())),
#else
      gtk_candidate_window_handler_(NULL),
#endif  // ENABLE_GTK_RENDERER
      ibus_candidate_window_handler_(new IBusCandidateWindowHandler()),
      preedit_method_(config::Config::ROMAN) {

  // Currently client capability is fixed.
  commands::Capability capability;
  capability.set_text_deletion(commands::Capability::DELETE_PRECEDING_TEXT);
  client_->set_client_capability(capability);
  // TODO(yusukes): write a unit test to check if the capability is set
  // as expected.
}

MozcEngine::~MozcEngine() {
  SyncData(true);
}

void MozcEngine::CandidateClicked(
    IBusEngine *engine,
    guint index,
    guint button,
    guint state) {
  if (index >= unique_candidate_ids_.size()) {
    return;
  }
  const int32 id = unique_candidate_ids_[index];
  if (id == kBadCandidateId) {
    return;
  }
  commands::Output output;
  commands::SessionCommand command;
  command.set_type(commands::SessionCommand::SELECT_CANDIDATE);
  command.set_id(id);
  client_->SendCommand(command, &output);
  UpdateAll(engine, output);
}

void MozcEngine::CursorDown(IBusEngine *engine) {
  // TODO(mazda): Implement this.
}

void MozcEngine::CursorUp(IBusEngine *engine) {
  // TODO(mazda): Implement this.
}

void MozcEngine::Disable(IBusEngine *engine) {
#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
  // Stop ignoring "reset" signal.  See ProcessKeyevent().
  ignore_reset_for_deletion_range_workaround_ = false;
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT

  RevertSession(engine);
  GetCandidateWindowHandler(engine)->Hide(engine);
}

void MozcEngine::Enable(IBusEngine *engine) {
#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
  // Stop ignoring "reset" signal.  See ProcessKeyevent().
  ignore_reset_for_deletion_range_workaround_ = false;
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT

  // Launch mozc_server
  client_->EnsureConnection();
  UpdatePreeditMethod();

  // When ibus-mozc is disabled by the "next input method" hot key, ibus-daemon
  // does not call MozcEngine::Disable(). Call RevertSession() here so the
  // mozc_server could discard a preedit string before the hot key is pressed
  // (crosbug.com/4596).
  RevertSession(engine);

#ifdef USE_IBUS_ENGINE_GET_SURROUNDING_TEXT
  // If engine wants to use surrounding text, we should call
  // ibus_engine_get_surrounding_text once when the engine enabled.
  ibus_engine_get_surrounding_text(engine, NULL, NULL, NULL);
#endif  // USE_IBUS_ENGINE_GET_SURROUNDING_TEXT
}

void MozcEngine::FocusIn(IBusEngine *engine) {
  property_handler_->Register(engine);
  UpdatePreeditMethod();
}

void MozcEngine::FocusOut(IBusEngine *engine) {
#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
  // Stop ignoring "reset" signal.  See ProcessKeyevent().
  ignore_reset_for_deletion_range_workaround_ = false;
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT

  GetCandidateWindowHandler(engine)->Hide(engine);

  // Do not call SubmitSession or RevertSession. Preedit string will commit on
  // Focus Out event automatically by ibus_engine_update_preedit_text_with_mode
  // which called in UpdatePreedit method.
  SyncData(false);
}

void MozcEngine::PageDown(IBusEngine *engine) {
  // TODO(mazda,yusukes): Implement this to support arrow icons inside the Gtk+
  // candidate window.
}

void MozcEngine::PageUp(IBusEngine *engine) {
  // TODO(mazda,yusukes): Implement this to support arrow icons inside the Gtk+
  // candidate window.
}

gboolean MozcEngine::ProcessKeyEvent(
    IBusEngine *engine,
    guint keyval,
    guint keycode,
    guint modifiers) {
  VLOG(2) << "keyval: " << keyval
          << ", keycode: " << keycode
          << ", modifiers: " << modifiers;

  // Send current caret location to mozc_server to manage suggest window
  // position.
  // TODO(nona): Merge SendKey event to reduce IPC cost.
  // TODO(nona): Add a unit test against b/6209562.
  SendCaretLocation(engine->cursor_area.x,
                    engine->cursor_area.y,
                    engine->cursor_area.width,
                    engine->cursor_area.height);

#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
  // Stop ignoring "reset" signal.  See the code of deletion below.
  ignore_reset_for_deletion_range_workaround_ = false;
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT

  // Since IBus for ChromeOS is based on in-process conversion,
  // it is basically ok to call GetConfig() at every keyevent.
  // On the other hands, IBus for Linux is based on out-process (IPC)
  // conversion and user may install large keybinding/roman-kana tables.
  // To reduce IPC overheads, we don't call UpdatePreeditMethod()
  // at every keyevent. When user changes the preedit method via
  // config dialog, the dialog shows a message saying that
  // "preedit method is enabled after new applications.".
  // This behavior is the same as Google Japanese Input for Windows.
#ifdef OS_CHROMEOS
  UpdatePreeditMethod();
#endif

  // TODO(yusukes): use |layout| in IBusEngineDesc if possible.
  const bool layout_is_jp =
      !g_strcmp0(ibus_engine_get_name(engine), "mozc-jp");

  commands::KeyEvent key;
  if (!key_event_handler_->GetKeyEvent(
          keyval, keycode, modifiers, preedit_method_, layout_is_jp, &key)) {
    // Doesn't send a key event to mozc_server.
    return FALSE;
  }

  VLOG(2) << key.DebugString();
  if (!property_handler_->IsActivated() &&
      !config::ImeSwitchUtil::IsDirectModeCommand(key)) {
    // We DO consume keys that should be handled even when in the DIRECT
    // mode such as (default) Henkan key to enable Mozc.
    return FALSE;
  }

  key.set_mode(property_handler_->GetOriginalCompositionMode());

  commands::Output output;
  if (!client_->SendKey(key, &output)) {
    LOG(ERROR) << "SendKey failed";
    return FALSE;
  }

  VLOG(2) << output.DebugString();

  UpdateAll(engine, output);

  const bool consumed = output.consumed();
  return consumed ? TRUE : FALSE;
}

void MozcEngine::PropertyActivate(IBusEngine *engine,
                                  const gchar *property_name,
                                  guint property_state) {
  property_handler_->ProcessPropertyActivate(engine, property_name,
                                             property_state);
}

void MozcEngine::PropertyHide(IBusEngine *engine,
                              const gchar *property_name) {
  // We can ignore the signal.
}

void MozcEngine::PropertyShow(IBusEngine *engine,
                              const gchar *property_name) {
  // We can ignore the signal.
}

void MozcEngine::Reset(IBusEngine *engine) {
#ifndef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
  // Ignore this signal if ignore_reset_for_deletion_range_workaround_ is true.
  // This is workaround of deletion of surrounding text.
  // See also ProcessKeyEvent().
  if (ignore_reset_for_deletion_range_workaround_) {
    VLOG(2) << "Reset signal is ignored";
    // We currently do not know the cases that application sends reset signal
    // more than once, so reset the flag here.
    ignore_reset_for_deletion_range_workaround_ = false;
    return;
  }
#endif  // !USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
  RevertSession(engine);
}

void MozcEngine::SetCapabilities(IBusEngine *engine,
                                 guint capabilities) {
  // Do nothing.
}

void MozcEngine::SetCursorLocation(IBusEngine *engine,
                                   gint x,
                                   gint y,
                                   gint w,
                                   gint h) {
  // Do nothing
}

GType MozcEngine::GetType() {
  static GType type = 0;

  static const GTypeInfo type_info = {
    sizeof(IBusMozcEngineClass),
    NULL,
    NULL,
    MozcEngineClassInit,
    NULL,
    NULL,
    sizeof(IBusMozcEngine),
    0,
    MozcEngineInstanceInit,
  };

  if (type == 0) {
    type = g_type_register_static(IBUS_TYPE_ENGINE,
                                  "IBusMozcEngine",
                                  &type_info,
                                  static_cast<GTypeFlags>(0));
    DCHECK_NE(type, 0) << "g_type_register_static failed";
  }

  return type;
}

// static
void MozcEngine::Disconnected(IBusBus *bus, gpointer user_data) {
  ibus_quit();
}

#if IBUS_CHECK_VERSION(1, 3, 99)
// For IBus 1.4.
void MozcEngine::ConfigValueChanged(IBusConfig *config,
                                    const gchar *section,
                                    const gchar *name,
                                    GVariant *value,
                                    gpointer user_data) {
  // This function might be called _before_ MozcEngineClassInit is called if
  // you press the "Configure..." button for Mozc before switching to the Mozc
  // input method.
  MozcEngine *engine = mozc::Singleton<MozcEngine>::get();
  engine->UpdateConfig(section, name, value);
}
#else
// For IBus 1.2 and 1.3.
void MozcEngine::ConfigValueChanged(IBusConfig *config,
                                    const gchar *section,
                                    const gchar *name,
                                    GValue *value,
                                    gpointer user_data) {
  MozcEngine *engine = mozc::Singleton<MozcEngine>::get();
  engine->UpdateConfig(section, name, value);
}
#endif

#ifdef ENABLE_GTK_RENDERER
void MozcEngine::InitRendererConfig(IBusConfig *config) {
#if IBUS_CHECK_VERSION(1, 4, 0)
  GVariant *custom_font_value = ibus_config_get_value(config,
                                                      kMozcPanelSectionName,
                                                      "custom_font");
  GVariant *use_custom_font_value = ibus_config_get_value(config,
                                                          kMozcPanelSectionName,
                                                          "use_custom_font");
#else
  // TODO(nona): Refactoring following logic or give up support 1.2.x
  GValue _custom_font_value = { 0 };
  GValue *custom_font_value = &_custom_font_value;
  ibus_config_get_value(config, kMozcPanelSectionName, "custom_font",
                        custom_font_value);

  GValue _use_custom_font_value = { 0 };
  GValue *use_custom_font_value = &_use_custom_font_value;
  ibus_config_get_value(config, kMozcPanelSectionName, "use_custom_font",
                        use_custom_font_value);
#endif  // IBUS >= 1.4.0
  gboolean use_custom_font;
  if (ConfigUtil::GetBoolean(use_custom_font_value, &use_custom_font)) {
    gtk_candidate_window_handler_->OnIBusUseCustomFontDescriptionChanged(
        static_cast<bool>(use_custom_font != FALSE));
  } else {
    LOG(ERROR) << "Initialize Failed: "
               << "Cannot get panel:use_custom_font configuration.";
  }
  const gchar *font_description;
  if (ConfigUtil::GetString(custom_font_value, &font_description)) {
    gtk_candidate_window_handler_->OnIBusCustomFontDescriptionChanged(
       font_description);
  } else {
    LOG(ERROR) << "Initialize Failed: "
               << "Cannot get panel:custom_font configuration.";
  }
}
#endif  // ENABLE_GTK_RENDERER

// TODO(mazda): Move the impelementation to an appropriate file.
void MozcEngine::InitConfig(IBusConfig *config) {
#ifdef ENABLE_GTK_RENDERER
  MozcEngine *engine = mozc::Singleton<MozcEngine>::get();
  engine->InitRendererConfig(config);
#endif  // ENABLE_GTK_RENDERER
#ifdef OS_CHROMEOS
  map<string, const char*> name_to_field;
  for (size_t i = 0; i < arraysize(kMozcConfigNames); ++i) {
    // Mozc uses identical names for ibus config names and protobuf config
    // field names.
    name_to_field.insert(make_pair(kMozcConfigNames[i], kMozcConfigNames[i]));
  }
  // Initialize the mozc config with the config loaded from ibus-memconf, which
  // is the primary config storage on Chrome OS.
  ConfigUtil::InitConfig(config, kMozcSectionName, name_to_field);
#endif  // OS_CHROMEOS
}


bool MozcEngine::UpdateAll(IBusEngine *engine, const commands::Output &output) {
  UpdateDeletionRange(engine, output);
  UpdateResult(engine, output);
  preedit_handler_->Update(engine, output);
  GetCandidateWindowHandler(engine)->Update(engine, output);
  UpdateCandidateIDMapping(output);

  property_handler_->Update(engine, output);

  LaunchTool(output);
  ExecuteCallback(engine, output);
  return true;
}

bool MozcEngine::UpdateDeletionRange(IBusEngine *engine,
                                     const commands::Output &output) {
  if (output.has_deletion_range() &&
      output.deletion_range().offset() < 0 &&
      output.deletion_range().offset() + output.deletion_range().length() >=
          0) {
#ifdef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
    // Nowadays 'ibus_engine_delete_surrounding_text' becomes functional on
    // many of the major applications.  Confirmed that it works on
    // Firefox 10.0, LibreOffice 3.3.4 and GEdit 3.2.3.
    ibus_engine_delete_surrounding_text(
        engine,
        output.deletion_range().offset(), output.deletion_range().length());
#else
    // Delete some characters of preceding text.  We really want to use
    // ibus_engine_delete_surrounding_text(), but it does not work on many
    // applications, e.g. Chrome, Firefox.  So we currently forward backspaces
    // to application.
    // NOTE: There are some workarounds.  They must be maintained
    // continuosly.
    // NOTE: It cannot delete range of characters not adjacent to the left side
    // of cursor.  If the range is not adjacent to the cursor, ignore it.  If
    // the range contains the cursor, only characters on the left side of cursor
    // are deleted.
    const int length = -output.deletion_range().offset();

    // Some applications, e.g. Chrome, delete preedit character when we forward
    // a backspace.  We can avoid it by hiding preedit before forwarding
    // backspaces.
    ibus_engine_hide_preedit_text(engine);

    // Forward backspaces.
    for (size_t i = 0; i < length; ++i) {
      ibus_engine_forward_key_event(
          engine, IBUS_BackSpace, kBackSpaceKeyCode, 0);
    }

    // This is a workaround.  Some applications (e.g. Chrome, etc.) send
    // strange signals such as "focus_out" and "focus_in" after forwarding
    // Backspace key event.  However, such strange signals are not sent if we
    // forward another key event after backspaces.  Here we choose Shift L,
    // which is one of the most quiet key event.
    ibus_engine_forward_key_event(engine, IBUS_Shift_L, kShiftLeftKeyCode, 0);

    // This is also a workaround.  Some applications (e.g. gedit, etc.) send a
    // "reset" signal after forwarding backspaces.  This signal is sent after
    // this ProcessKeyEvent() returns, and we want to avoid reverting the
    // session.
    // See also Reset(), which calls RevertSession() only if
    // ignore_reset_for_deletion_range_workaround_ is false.  This flag is
    // reset on Disable(), FocusOut(), and ProcessKeyEvent().  Reset() also
    // reset this flag, i.e. this flag does not work more than once.
    ignore_reset_for_deletion_range_workaround_ = true;
#endif
  }
  return true;
}

bool MozcEngine::UpdateResult(IBusEngine *engine,
                              const commands::Output &output) const {
  if (!output.has_result()) {
    VLOG(2) << "output doesn't contain result";
    return true;
  }

  IBusText *text = ibus_text_new_from_string(output.result().value().c_str());
  ibus_engine_commit_text(engine, text);
  // |text| is released by ibus_engine_commit_text.
  return true;
}

bool MozcEngine::UpdateCandidateIDMapping(const commands::Output &output) {
  if (!output.has_candidates() || output.candidates().candidate_size() == 0) {
    return true;
  }

  unique_candidate_ids_.clear();
  const commands::Candidates &candidates = output.candidates();
  for (int i = 0; i < candidates.candidate_size(); ++i) {
    if (candidates.candidate(i).has_id()) {
      const int32 id = candidates.candidate(i).id();
      unique_candidate_ids_.push_back(id);
    } else {
      // The parent node of the cascading window does not have an id since the
      // node does not contain a candidate word.
      unique_candidate_ids_.push_back(kBadCandidateId);
    }
  }
  return true;
}

void MozcEngine::UpdateConfig(const gchar *section,
                              const gchar *name,
#if IBUS_CHECK_VERSION(1, 3, 99)
                              GVariant *value
#else
                              GValue *value
#endif
                              ) {
  if (!section || !name || !value) {
    return;
  }
#ifdef ENABLE_GTK_RENDERER
  // TODO(nona): Introduce ConfigHandler
  if (g_strcmp0(section, kMozcPanelSectionName) == 0) {
    if (g_strcmp0(name, "use_custom_font") == 0) {
      gboolean use_custom_font;
      if (!ConfigUtil::GetBoolean(value, &use_custom_font)) {
        LOG(ERROR) << "Cannot get " << section << ":" << name << " value.";
        return;
      }
      gtk_candidate_window_handler_->OnIBusUseCustomFontDescriptionChanged(
          static_cast<bool>(use_custom_font != FALSE));
    } else if (g_strcmp0(name, "custom_font") == 0) {
      const gchar *font_description;
      if (!ConfigUtil::GetString(value, &font_description)) {
        LOG(ERROR) << "Cannot get " << section << ":" << name << " value.";
        return;
      }
      gtk_candidate_window_handler_->OnIBusCustomFontDescriptionChanged(
          font_description);
    }
  }
#endif  // ENABLE_GTK_RENDERER
#ifdef OS_CHROMEOS
  if (g_strcmp0(section, kMozcSectionName) == 0) {
    config::Config mozc_config;
    client_->GetConfig(&mozc_config);
    ConfigUtil::SetFieldForName(name, value, &mozc_config);

    // Update config1.db.
    client_->SetConfig(mozc_config);
    client_->SyncData();  // TODO(yusukes): remove this call?
    VLOG(2) << "Client::SetConfig() is called: " << name;
  }
#endif  // OS_CHROMEOS
}

void MozcEngine::UpdatePreeditMethod() {
  config::Config config;
  if (!client_->GetConfig(&config)) {
    LOG(ERROR) << "GetConfig failed";
    return;
  }
  preedit_method_ = config.has_preedit_method() ?
      config.preedit_method() : config::Config::ROMAN;
}

void MozcEngine::SyncData(bool force) {
  if (client_.get() == NULL) {
    return;
  }

  const uint64 current_time = Util::GetTime();
  if (force ||
      (current_time >= last_sync_time_ &&
       current_time - last_sync_time_ >= kSyncDataInterval)) {
    VLOG(1) << "Syncing data";
    client_->SyncData();
    last_sync_time_ = current_time;
  }
}

bool MozcEngine::LaunchTool(const commands::Output &output) const {
  if (!client_->LaunchToolWithProtoBuf(output)) {
    VLOG(2) << output.DebugString() << " Launch Failed";
    return false;
  }

  return true;
}

void MozcEngine::RevertSession(IBusEngine *engine) {
  commands::SessionCommand command;
  command.set_type(commands::SessionCommand::REVERT);
  commands::Output output;
  if (!client_->SendCommand(command, &output)) {
    LOG(ERROR) << "RevertSession() failed";
    return;
  }
  UpdateAll(engine, output);
}

bool MozcEngine::ExecuteCallback(IBusEngine *engine,
                                 const commands::Output &output) {
  if (!output.has_callback()) {
    return false;
  }

  // TODO(nona): Make IBus interface class and add unittest for ibus APIs.
  if (!output.callback().has_session_command()) {
    LOG(ERROR) << "callback does not have session_command";
    return false;
  }

  const commands::SessionCommand &callback_command =
      output.callback().session_command();

  if (!callback_command.has_type()) {
    LOG(ERROR) << "callback_command has no type";
    return false;
  }

  commands::SessionCommand session_command;
  session_command.set_type(callback_command.type());

#if defined(USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT) ||  \
    defined(USE_IBUS_ENGINE_GET_SURROUNDING_TEXT)
  // TODO(nona): Make a function to handle CONVERT_REVERSE.
  // Used by CONVERT_REVERSE and/or UNDO
  // This value represents how many characters are selected as a relative
  // distance of characters. Positive value represents forward text selection
  // and negative value represents backword text selection.
  // Note that you should not allow 0x80000000 for |relative_selected_length|
  // because you cannot safely use |-relative_selected_length| nor
  // |abs(relative_selected_length)| in this case due to integer overflow.
  int32 relative_selected_length = 0;
#endif  // USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT ||
        // USE_IBUS_ENGINE_GET_SURROUNDING_TEXT

  switch (callback_command.type()) {
    case commands::SessionCommand::UNDO:
      // As far as I've tested on Ubuntu 11.10, most of applications which
      // accept 'ibus_engine_delete_surrounding_text' doe not set
      // IBUS_CAP_SURROUNDING_TEXT bit.
      // So we should carefully uncomment the following code.
      // -----
      // #ifdef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
      // if (!(engine->client_capabilities & IBUS_CAP_SURROUNDING_TEXT)) {
      //   return false;
      // }
      // #endif  // USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
      break;
    case commands::SessionCommand::CONVERT_REVERSE: {
#ifdef USE_IBUS_ENGINE_GET_SURROUNDING_TEXT
      if (!(engine->client_capabilities & IBUS_CAP_SURROUNDING_TEXT)) {
        return false;
      }
      IBusText *text = NULL;
      guint cursor_pos = 0;
      guint anchor_pos = 0;

      ibus_engine_get_surrounding_text(engine, &text, &cursor_pos,
                                       &anchor_pos);
      if (cursor_pos == anchor_pos) {
        // There are no selection texts.
        return false;
      }

      if (!GetSafeDelta(cursor_pos, anchor_pos, &relative_selected_length)) {
        LOG(ERROR) << "Too long text selection.";
        return false;
      }

      const string surrounding_text(ibus_text_get_text(text));
      g_object_unref(text);

      // TODO(nona): Write a test for this logic (especially selection_length).
      // TODO(nona): Check integer range because Util::SubString works
      //     on size_t, not uint32.
      string selection_text;
      const uint32 selection_start = min(cursor_pos, anchor_pos);
      const uint32 selection_length = abs(relative_selected_length);
      Util::SubString(surrounding_text,
                      selection_start,
                      selection_length,
                      &selection_text);

      session_command.set_text(selection_text);
      break;
#else
      return false;
#endif
    }
    default:
      return false;
  }

  commands::Output new_output;
  if (!client_->SendCommand(session_command, &new_output)) {
    LOG(ERROR) << "Callback Command Failed";
    return false;
  }

  if (callback_command.type() == commands::SessionCommand::CONVERT_REVERSE) {
    // We need to remove selected text as a first step of reconversion.
    commands::DeletionRange *range = new_output.mutable_deletion_range();
#ifdef USE_IBUS_ENGINE_DELETE_SURROUNDING_TEXT
    // Use DeletionRange field to remove the selected text.
    // For forward selection (that is, |relative_selected_length > 0|), the
    // offset should be a negative value to delete preceding text.
    // For backward selection (that is, |relative_selected_length < 0|),
    // IBus and/or some applications seem to expect |offset == 0| somehow.
    const int32 offset = relative_selected_length > 0
        ? -relative_selected_length  // forward selection
        : 0;                         // backward selection
    range->set_offset(offset);
    range->set_length(abs(relative_selected_length));
#else
    // Send backspace key event once to remove selection area.
    // To set deletion range as follows, the engine forwards backspace key event
    // once to the client application via ibus-daemon.
    range->set_offset(-1);
    range->set_length(1);
#endif
  }

  // Here uses recursion of UpdateAll but it's okay because the converter
  // ensures that the second output never contains callback.
  UpdateAll(engine, new_output);
  return true;
}

CandidateWindowHandlerInterface *MozcEngine::GetCandidateWindowHandler(
    IBusEngine *engine) {
#ifndef ENABLE_GTK_RENDERER
  return ibus_candidate_window_handler_.get();
#else
  if (!FLAGS_use_mozc_candidate_window) {
    return ibus_candidate_window_handler_.get();
  }

  if (!(engine->client_capabilities & IBUS_CAP_PREEDIT_TEXT)) {
    return ibus_candidate_window_handler_.get();
  }

  // TODO(nona): integrate with renderer/renderer_client.cc
  const string renderer_path = mozc::Util::JoinPath(
      mozc::Util::GetServerDirectory(), "mozc_renderer");
  if (!Util::FileExists(renderer_path)) {
    return ibus_candidate_window_handler_.get();
  }

  // TODO(nona): Check executable bit for renderer.
  return gtk_candidate_window_handler_.get();
#endif  // not ENABLE_GTK_RENDERER
}

void MozcEngine::SendCaretLocation(uint32 x, uint32 y, uint32 width,
                                   uint32 height) {
  commands::Output output;
  commands::SessionCommand command;
  command.set_type(commands::SessionCommand::SEND_CARET_LOCATION);
  commands::Rectangle *caret_rectangle = command.mutable_caret_rectangle();
  caret_rectangle->set_x(x);
  caret_rectangle->set_y(y);
  caret_rectangle->set_width(width);
  caret_rectangle->set_height(height);
  client_->SendCommand(command, &output);
}

}  // namespace ibus
}  // namespace mozc