ui/base/webui/web_ui_util.cc

// Copyright 2013 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 "ui/base/webui/web_ui_util.h"

#include <vector>

#include "base/base64.h"
#include "base/feature_list.h"
#include "base/i18n/rtl.h"
#include "base/logging.h"
#include "base/memory/ref_counted_memory.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_piece.h"
#include "base/strings/string_util.h"
#include "base/trace_event/trace_event.h"
#include "build/build_config.h"
#include "build/chromeos_buildflags.h"
#include "net/base/escape.h"
#include "third_party/modp_b64/modp_b64.h"
#include "third_party/skia/include/core/SkBitmap.h"
#include "ui/base/l10n/l10n_util.h"
#include "ui/base/resource/resource_bundle.h"
#include "ui/base/template_expressions.h"
#include "ui/base/window_open_disposition.h"
#include "ui/gfx/codec/png_codec.h"
#include "ui/gfx/font.h"
#include "ui/gfx/image/image_skia.h"
#include "ui/resources/grit/webui_generated_resources.h"
#include "ui/strings/grit/app_locale_settings.h"
#include "url/gurl.h"

#if BUILDFLAG(IS_WIN)
#include "base/win/windows_version.h"
#endif

namespace webui {
namespace {
std::string GetWebUiCssTextDefaults(const std::string& css_template) {
  ui::TemplateReplacements placeholders;
  placeholders["textDirection"] = GetTextDirection();
  placeholders["fontFamily"] = GetFontFamily();
  placeholders["fontSize"] = GetFontSize();
  return ui::ReplaceTemplateExpressions(css_template, placeholders);
}
}  // namespace

std::string GetBitmapDataUrl(const SkBitmap& bitmap) {
  TRACE_EVENT2("ui", "GetBitmapDataUrl", "width", bitmap.width(), "height",
               bitmap.height());
  std::vector<unsigned char> output;
  gfx::PNGCodec::EncodeBGRASkBitmap(bitmap, false, &output);
  return GetPngDataUrl(output.data(), output.size());
}

std::string GetPngDataUrl(const unsigned char* data, size_t size) {
  constexpr char kPrefix[] = "data:image/png;base64,";
  constexpr size_t kPrefixLen = std::size(kPrefix) - 1;
  // Includes room for trailing null byte.
  size_t max_encode_len = modp_b64_encode_len(size);
  std::string output;
  // This initializes the characters in the string, but there's no good way to
  // avoid that and maintain a std::string API.
  output.resize(kPrefixLen + max_encode_len);
  memcpy(&output[0], kPrefix, kPrefixLen);
  // |max_encode_len| is >= 1, so &output[kPrefixLen] is valid.
  size_t actual_encode_len = modp_b64_encode(
      &output[kPrefixLen], reinterpret_cast<const char*>(data), size);
  output.resize(kPrefixLen + actual_encode_len);
  return output;
}

WindowOpenDisposition GetDispositionFromClick(const base::ListValue* args,
                                              int start_index) {
  base::Value::ConstListView list = args->GetListDeprecated();
  double button = list[start_index].GetDouble();
  bool alt_key = list[start_index + 1].GetBool();
  bool ctrl_key = list[start_index + 2].GetBool();
  bool meta_key = list[start_index + 3].GetBool();
  bool shift_key = list[start_index + 4].GetBool();

  return ui::DispositionFromClick(
      button == 1.0, alt_key, ctrl_key, meta_key, shift_key);
}

bool ParseScaleFactor(const base::StringPiece& identifier,
                      float* scale_factor) {
  *scale_factor = 1.0f;
  if (identifier.empty()) {
    LOG(WARNING) << "Invalid scale factor format: " << identifier;
    return false;
  }

  if (*identifier.rbegin() != 'x') {
    LOG(WARNING) << "Invalid scale factor format: " << identifier;
    return false;
  }

  double scale = 0;
  std::string stripped(identifier.substr(0, identifier.length() - 1));
  if (!base::StringToDouble(stripped, &scale)) {
    LOG(WARNING) << "Invalid scale factor format: " << identifier;
    return false;
  }
  *scale_factor = static_cast<float>(scale);
  return true;
}

// Parse a formatted frame index string into int and sets to |frame_index|.
bool ParseFrameIndex(const base::StringPiece& identifier, int* frame_index) {
  *frame_index = -1;
  if (identifier.empty()) {
    LOG(WARNING) << "Invalid frame index format: " << identifier;
    return false;
  }

  if (*identifier.rbegin() != ']') {
    LOG(WARNING) << "Invalid frame index format: " << identifier;
    return false;
  }

  unsigned frame = 0;
  if (!base::StringToUint(identifier.substr(0, identifier.length() - 1),
                          &frame)) {
    LOG(WARNING) << "Invalid frame index format: " << identifier;
    return false;
  }
  *frame_index = static_cast<int>(frame);
  return true;
}

void ParsePathAndImageSpec(const GURL& url,
                           std::string* path,
                           float* scale_factor,
                           int* frame_index) {
  *path = net::UnescapeBinaryURLComponent(url.path_piece().substr(1));
  if (scale_factor)
    *scale_factor = 1.0f;
  if (frame_index)
    *frame_index = -1;

  // Detect and parse resource string ending in @<scale>x.
  std::size_t pos = path->rfind('@');
  if (pos != std::string::npos) {
    base::StringPiece stripped_path(*path);
    float factor;

    if (ParseScaleFactor(stripped_path.substr(
            pos + 1, stripped_path.length() - pos - 1), &factor)) {
      // Strip scale factor specification from path.
      stripped_path.remove_suffix(stripped_path.length() - pos);
      path->assign(stripped_path.data(), stripped_path.size());
    }
    if (scale_factor)
      *scale_factor = factor;
  }

  // Detect and parse resource string ending in [<frame>].
  pos = path->rfind('[');
  if (pos != std::string::npos) {
    base::StringPiece stripped_path(*path);
    int index;

    if (ParseFrameIndex(
            stripped_path.substr(pos + 1, stripped_path.length() - pos - 1),
            &index)) {
      // Strip frame index specification from path.
      stripped_path.remove_suffix(stripped_path.length() - pos);
      path->assign(stripped_path.data(), stripped_path.size());
    }
    if (frame_index)
      *frame_index = index;
  }
}

void ParsePathAndScale(const GURL& url,
                       std::string* path,
                       float* scale_factor) {
  ParsePathAndImageSpec(url, path, scale_factor, nullptr);
}

void SetLoadTimeDataDefaults(const std::string& app_locale,
                             base::Value* localized_strings) {
  SetLoadTimeDataDefaults(app_locale, localized_strings->GetIfDict());
}

void SetLoadTimeDataDefaults(const std::string& app_locale,
                             base::Value::Dict* localized_strings) {
  localized_strings->Set("fontfamily", GetFontFamily());
  localized_strings->Set("fontsize", GetFontSize());
  localized_strings->Set("language", l10n_util::GetLanguage(app_locale));
  localized_strings->Set("textdirection", GetTextDirection());
}

void SetLoadTimeDataDefaults(const std::string& app_locale,
                             ui::TemplateReplacements* replacements) {
  (*replacements)["fontfamily"] = GetFontFamily();
  (*replacements)["fontsize"] = GetFontSize();
  (*replacements)["language"] = l10n_util::GetLanguage(app_locale);
  (*replacements)["textdirection"] = GetTextDirection();
}

std::string GetWebUiCssTextDefaults() {
  const ui::ResourceBundle& resource_bundle =
      ui::ResourceBundle::GetSharedInstance();
  return GetWebUiCssTextDefaults(
      resource_bundle.LoadDataResourceString(IDR_WEBUI_CSS_TEXT_DEFAULTS_CSS));
}

std::string GetWebUiCssTextDefaultsMd() {
  const ui::ResourceBundle& resource_bundle =
      ui::ResourceBundle::GetSharedInstance();
  return GetWebUiCssTextDefaults(resource_bundle.LoadDataResourceString(
      IDR_WEBUI_CSS_TEXT_DEFAULTS_MD_CSS));
}

void AppendWebUiCssTextDefaults(std::string* html) {
  html->append("<style>");
  html->append(GetWebUiCssTextDefaults());
  html->append("</style>");
}

std::string GetFontFamily() {
  std::string font_family = l10n_util::GetStringUTF8(IDS_WEB_FONT_FAMILY);

// TODO(crbug.com/1052397): Revisit the macro expression once build flag switch
// of lacros-chrome is complete.
#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)
  std::string font_name = ui::ResourceBundle::GetSharedInstance()
                              .GetFont(ui::ResourceBundle::BaseFont)
                              .GetFontName();
  // Wrap |font_name| with quotes to ensure it will always be parsed correctly
  // in CSS.
  font_family = "\"" + font_name + "\", " + font_family;
#endif

  return font_family;
}

std::string GetFontSize() {
  return l10n_util::GetStringUTF8(IDS_WEB_FONT_SIZE);
}

std::string GetTextDirection() {
  return base::i18n::IsRTL() ? "rtl" : "ltr";
}

}  // namespace webui