ui/linux/linux_ui_factory.cc

// Copyright 2022 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/linux/linux_ui_factory.h"

#include <memory>
#include <utility>

#include "base/command_line.h"
#include "base/environment.h"
#include "base/nix/xdg_util.h"
#include "base/strings/string_util.h"
#include "ui/base/buildflags.h"
#include "ui/color/system_theme.h"
#include "ui/linux/linux_ui.h"
#include "ui/linux/linux_ui_delegate.h"

#if BUILDFLAG(USE_GTK)
#include "ui/gtk/gtk_ui_factory.h"
#endif
#if BUILDFLAG(USE_QT)
#include "ui/qt/qt_ui.h"
#endif

namespace ui {

namespace {

const char kUiToolkitFlag[] = "ui-toolkit";

std::unique_ptr<LinuxUiAndTheme> CreateGtkUi() {
#if BUILDFLAG(USE_GTK)
  auto gtk_ui = BuildGtkUi();
  if (gtk_ui->Initialize())
    return gtk_ui;
#endif
  return nullptr;
}

LinuxUiAndTheme* GetGtkUi() {
  // LinuxUi creation will fail without a delegate.
  if (!ui::LinuxUiDelegate::GetInstance())
    return nullptr;
  static LinuxUiAndTheme* gtk_ui = CreateGtkUi().release();
  return gtk_ui;
}

std::unique_ptr<LinuxUiAndTheme> CreateQtUi() {
  if (!base::FeatureList::IsEnabled(kAllowQt))
    return nullptr;
#if BUILDFLAG(USE_QT)
  auto qt_ui = qt::CreateQtUi(GetGtkUi());
  if (qt_ui->Initialize())
    return qt_ui;
#endif
  return nullptr;
}

LinuxUiAndTheme* GetQtUi() {
  // LinuxUi creation will fail without a delegate.
  if (!ui::LinuxUiDelegate::GetInstance())
    return nullptr;
  static LinuxUiAndTheme* qt_ui = CreateQtUi().release();
  return qt_ui;
}

LinuxUiAndTheme* GetDefaultLinuxUiAndTheme() {
  auto* cmd_line = base::CommandLine::ForCurrentProcess();
  std::string ui_toolkit =
      base::ToLowerASCII(cmd_line->GetSwitchValueASCII(kUiToolkitFlag));
  if (ui_toolkit == "gtk") {
    if (auto* gtk_ui = GetGtkUi())
      return gtk_ui;
  } else if (ui_toolkit == "qt") {
    if (auto* qt_ui = GetQtUi())
      return qt_ui;
  }

  std::unique_ptr<base::Environment> env = base::Environment::Create();
  switch (GetDefaultSystemTheme()) {
    case SystemTheme::kQt:
      if (auto* qt_ui = GetQtUi())
        return qt_ui;
      return GetGtkUi();
    case SystemTheme::kGtk:
    case SystemTheme::kDefault:
      if (auto* gtk_ui = GetGtkUi())
        return gtk_ui;
      return GetQtUi();
  }
}

}  // namespace

const base::Feature kAllowQt{"AllowQt", base::FEATURE_DISABLED_BY_DEFAULT};

LinuxUi* GetDefaultLinuxUi() {
  return GetDefaultLinuxUiAndTheme();
}

LinuxUiTheme* GetDefaultLinuxUiTheme() {
  return GetDefaultLinuxUiAndTheme();
}

LinuxUiTheme* GetLinuxUiTheme(SystemTheme system_theme) {
  switch (system_theme) {
    case SystemTheme::kQt:
      return GetQtUi();
    case SystemTheme::kGtk:
      return GetGtkUi();
    case SystemTheme::kDefault:
      return nullptr;
  }
}

SystemTheme GetDefaultSystemTheme() {
  std::unique_ptr<base::Environment> env = base::Environment::Create();

  switch (base::nix::GetDesktopEnvironment(env.get())) {
    case base::nix::DESKTOP_ENVIRONMENT_CINNAMON:
    case base::nix::DESKTOP_ENVIRONMENT_GNOME:
    case base::nix::DESKTOP_ENVIRONMENT_PANTHEON:
    case base::nix::DESKTOP_ENVIRONMENT_UNITY:
    case base::nix::DESKTOP_ENVIRONMENT_XFCE:
      return SystemTheme::kGtk;
    case base::nix::DESKTOP_ENVIRONMENT_KDE3:
    case base::nix::DESKTOP_ENVIRONMENT_KDE4:
    case base::nix::DESKTOP_ENVIRONMENT_KDE5:
    case base::nix::DESKTOP_ENVIRONMENT_UKUI:
    case base::nix::DESKTOP_ENVIRONMENT_DEEPIN:
    case base::nix::DESKTOP_ENVIRONMENT_LXQT:
      return SystemTheme::kQt;
    case base::nix::DESKTOP_ENVIRONMENT_OTHER:
      return SystemTheme::kDefault;
  }
}

}  // namespace ui