electron/shell/browser/font_defaults.cc

// Copyright (c) 2018 Slack Technologies, Inc.
// Use of this source code is governed by the MIT license that can be
// found in the LICENSE file.

#include "shell/browser/font_defaults.h"

#include <array>
#include <string>
#include <string_view>

#include "base/stl_util.h"
#include "base/strings/strcat.h"
#include "base/strings/utf_string_conversions.h"
#include "chrome/common/pref_names.h"
#include "chrome/grit/platform_locale_settings.h"
#include "third_party/blink/public/common/web_preferences/web_preferences.h"
#include "ui/base/l10n/l10n_util.h"

namespace {

// The following list of font defaults was copied from
// https://chromium.googlesource.com/chromium/src/+/69.0.3497.106/chrome/browser/ui/prefs/prefs_tab_helper.cc#152
//
// The only updates that should be made to this list are copying updates that
// were made in Chromium.
//
// vvvvv DO NOT EDIT vvvvv

struct FontDefault {
  const char* pref_name;
  int resource_id;
};

// Font pref defaults.  The prefs that have defaults vary by platform, since not
// all platforms have fonts for all scripts for all generic families.
// TODO(falken): add proper defaults when possible for all
// platforms/scripts/generic families.
const FontDefault kFontDefaults[] = {
    {prefs::kWebKitStandardFontFamily, IDS_STANDARD_FONT_FAMILY},
    {prefs::kWebKitFixedFontFamily, IDS_FIXED_FONT_FAMILY},
    {prefs::kWebKitSerifFontFamily, IDS_SERIF_FONT_FAMILY},
    {prefs::kWebKitSansSerifFontFamily, IDS_SANS_SERIF_FONT_FAMILY},
    {prefs::kWebKitCursiveFontFamily, IDS_CURSIVE_FONT_FAMILY},
    {prefs::kWebKitFantasyFontFamily, IDS_FANTASY_FONT_FAMILY},
#if BUILDFLAG(IS_CHROMEOS) || BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)
    {prefs::kWebKitStandardFontFamilyJapanese,
     IDS_STANDARD_FONT_FAMILY_JAPANESE},
    {prefs::kWebKitFixedFontFamilyJapanese, IDS_FIXED_FONT_FAMILY_JAPANESE},
    {prefs::kWebKitSerifFontFamilyJapanese, IDS_SERIF_FONT_FAMILY_JAPANESE},
    {prefs::kWebKitSansSerifFontFamilyJapanese,
     IDS_SANS_SERIF_FONT_FAMILY_JAPANESE},
    {prefs::kWebKitStandardFontFamilyKorean, IDS_STANDARD_FONT_FAMILY_KOREAN},
    {prefs::kWebKitSerifFontFamilyKorean, IDS_SERIF_FONT_FAMILY_KOREAN},
    {prefs::kWebKitSansSerifFontFamilyKorean,
     IDS_SANS_SERIF_FONT_FAMILY_KOREAN},
    {prefs::kWebKitStandardFontFamilySimplifiedHan,
     IDS_STANDARD_FONT_FAMILY_SIMPLIFIED_HAN},
    {prefs::kWebKitSerifFontFamilySimplifiedHan,
     IDS_SERIF_FONT_FAMILY_SIMPLIFIED_HAN},
    {prefs::kWebKitSansSerifFontFamilySimplifiedHan,
     IDS_SANS_SERIF_FONT_FAMILY_SIMPLIFIED_HAN},
    {prefs::kWebKitStandardFontFamilyTraditionalHan,
     IDS_STANDARD_FONT_FAMILY_TRADITIONAL_HAN},
    {prefs::kWebKitSerifFontFamilyTraditionalHan,
     IDS_SERIF_FONT_FAMILY_TRADITIONAL_HAN},
    {prefs::kWebKitSansSerifFontFamilyTraditionalHan,
     IDS_SANS_SERIF_FONT_FAMILY_TRADITIONAL_HAN},
#endif
#if BUILDFLAG(IS_MAC) || BUILDFLAG(IS_WIN)
    {prefs::kWebKitCursiveFontFamilySimplifiedHan,
     IDS_CURSIVE_FONT_FAMILY_SIMPLIFIED_HAN},
    {prefs::kWebKitCursiveFontFamilyTraditionalHan,
     IDS_CURSIVE_FONT_FAMILY_TRADITIONAL_HAN},
#endif
#if BUILDFLAG(IS_CHROMEOS)
    {prefs::kWebKitStandardFontFamilyArabic, IDS_STANDARD_FONT_FAMILY_ARABIC},
    {prefs::kWebKitSerifFontFamilyArabic, IDS_SERIF_FONT_FAMILY_ARABIC},
    {prefs::kWebKitSansSerifFontFamilyArabic,
     IDS_SANS_SERIF_FONT_FAMILY_ARABIC},
    {prefs::kWebKitFixedFontFamilyKorean, IDS_FIXED_FONT_FAMILY_KOREAN},
    {prefs::kWebKitFixedFontFamilySimplifiedHan,
     IDS_FIXED_FONT_FAMILY_SIMPLIFIED_HAN},
    {prefs::kWebKitFixedFontFamilyTraditionalHan,
     IDS_FIXED_FONT_FAMILY_TRADITIONAL_HAN},
#elif BUILDFLAG(IS_WIN)
    {prefs::kWebKitFixedFontFamilyArabic, IDS_FIXED_FONT_FAMILY_ARABIC},
    {prefs::kWebKitSansSerifFontFamilyArabic,
     IDS_SANS_SERIF_FONT_FAMILY_ARABIC},
    {prefs::kWebKitStandardFontFamilyCyrillic,
     IDS_STANDARD_FONT_FAMILY_CYRILLIC},
    {prefs::kWebKitFixedFontFamilyCyrillic, IDS_FIXED_FONT_FAMILY_CYRILLIC},
    {prefs::kWebKitSerifFontFamilyCyrillic, IDS_SERIF_FONT_FAMILY_CYRILLIC},
    {prefs::kWebKitSansSerifFontFamilyCyrillic,
     IDS_SANS_SERIF_FONT_FAMILY_CYRILLIC},
    {prefs::kWebKitStandardFontFamilyGreek, IDS_STANDARD_FONT_FAMILY_GREEK},
    {prefs::kWebKitFixedFontFamilyGreek, IDS_FIXED_FONT_FAMILY_GREEK},
    {prefs::kWebKitSerifFontFamilyGreek, IDS_SERIF_FONT_FAMILY_GREEK},
    {prefs::kWebKitSansSerifFontFamilyGreek, IDS_SANS_SERIF_FONT_FAMILY_GREEK},
    {prefs::kWebKitFixedFontFamilyKorean, IDS_FIXED_FONT_FAMILY_KOREAN},
    {prefs::kWebKitCursiveFontFamilyKorean, IDS_CURSIVE_FONT_FAMILY_KOREAN},
    {prefs::kWebKitFixedFontFamilySimplifiedHan,
     IDS_FIXED_FONT_FAMILY_SIMPLIFIED_HAN},
    {prefs::kWebKitFixedFontFamilyTraditionalHan,
     IDS_FIXED_FONT_FAMILY_TRADITIONAL_HAN},
#endif
};

// ^^^^^ DO NOT EDIT ^^^^^

// Get `kFontDefault`'s default fontname for [font family, script].
// e.g. ("webkit.webprefs.fonts.fixed", "Zyyy") -> "Monospace"
std::string GetDefaultFont(const std::string_view family_name,
                           const std::string_view script_name) {
  const std::string pref_name = base::StrCat({family_name, ".", script_name});

  for (const FontDefault& pref : kFontDefaults) {
    if (pref_name == pref.pref_name) {
      return l10n_util::GetStringUTF8(pref.resource_id);
    }
  }

  return std::string{};
}

// Each font family has kWebKitScriptsForFontFamilyMapsLength scripts.
// This is a lookup array for script_index -> fontname
using PerFamilyFonts =
    std::array<std::u16string, prefs::kWebKitScriptsForFontFamilyMapsLength>;

PerFamilyFonts MakeCacheForFamily(const std::string_view family_name) {
  PerFamilyFonts ret;
  for (size_t i = 0; i < prefs::kWebKitScriptsForFontFamilyMapsLength; ++i) {
    const char* script_name = prefs::kWebKitScriptsForFontFamilyMaps[i];
    ret[i] = base::UTF8ToUTF16(GetDefaultFont(family_name, script_name));
  }
  return ret;
}

void FillFontFamilyMap(const PerFamilyFonts& cache,
                       blink::web_pref::ScriptFontFamilyMap& font_family_map) {
  for (size_t i = 0; i < prefs::kWebKitScriptsForFontFamilyMapsLength; ++i) {
    if (const std::u16string& fontname = cache[i]; !fontname.empty()) {
      char const* const script_name = prefs::kWebKitScriptsForFontFamilyMaps[i];
      font_family_map[script_name] = fontname;
    }
  }
}

struct FamilyCache {
  std::string_view family_name;

  // where to find the font_family_map in a WebPreferences instance
  blink::web_pref::ScriptFontFamilyMap blink::web_pref::WebPreferences::*
      map_offset;

  PerFamilyFonts fonts = {};
};

static auto MakeCache() {
  // the font families whose defaults we want to cache
  std::array<FamilyCache, 5> cache{{
      {prefs::kWebKitStandardFontFamilyMap,
       &blink::web_pref::WebPreferences::standard_font_family_map},
      {prefs::kWebKitFixedFontFamilyMap,
       &blink::web_pref::WebPreferences::fixed_font_family_map},
      {prefs::kWebKitSerifFontFamilyMap,
       &blink::web_pref::WebPreferences::serif_font_family_map},
      {prefs::kWebKitSansSerifFontFamilyMap,
       &blink::web_pref::WebPreferences::sans_serif_font_family_map},
      {prefs::kWebKitCursiveFontFamilyMap,
       &blink::web_pref::WebPreferences::cursive_font_family_map},
  }};

  // populate the cache
  for (FamilyCache& row : cache) {
    row.fonts = MakeCacheForFamily(row.family_name);
  }

  return cache;
}

}  // namespace

namespace electron {

void SetFontDefaults(blink::web_pref::WebPreferences* prefs) {
  static auto const cache = MakeCache();

  for (FamilyCache const& row : cache) {
    FillFontFamilyMap(row.fonts, prefs->*row.map_offset);
  }
}

}  // namespace electron