text: // 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 "chrome/browser/extensions/convert_web_app.h"
  
  #include <cmath>
  #include <limits>
  #include <string>
  #include <vector>
  
  #include "base/base64.h"
  #include "base/file_path.h"
  #include "base/file_util.h"
  #include "base/logging.h"
  #include "base/memory/scoped_temp_dir.h"
  #include "base/path_service.h"
  #include "base/stringprintf.h"
  #include "base/time.h"
  #include "base/utf_string_conversions.h"
  #include "crypto/sha2.h"
  #include "chrome/common/chrome_paths.h"
  #include "chrome/common/extensions/extension.h"
  #include "chrome/common/extensions/extension_constants.h"
  #include "chrome/common/extensions/extension_file_util.h"
  #include "chrome/common/web_apps.h"
  #include "content/common/json_value_serializer.h"
  #include "googleurl/src/gurl.h"
  #include "third_party/skia/include/core/SkBitmap.h"
  #include "ui/gfx/codec/png_codec.h"
  
  namespace keys = extension_manifest_keys;
  
  using base::Time;
  
  namespace {
  
  const char kIconsDirName[] = "icons";
  
  // Create the public key for the converted web app.
  //
  // Web apps are not signed, but the public key for an extension doubles as
  // its unique identity, and we need one of those. A web app's unique identity
  // is its manifest URL, so we hash that to create a public key. There will be
  // no corresponding private key, which means that these extensions cannot be
  // auto-updated using ExtensionUpdater. But Chrome does notice updates to the
  // manifest and regenerates these extensions.
  std::string GenerateKey(const GURL& manifest_url) {
    char raw[crypto::SHA256_LENGTH] = {0};
    std::string key;
    crypto::SHA256HashString(manifest_url.spec().c_str(),
                             raw,
                             crypto::SHA256_LENGTH);
    base::Base64Encode(std::string(raw, crypto::SHA256_LENGTH), &key);
    return key;
  }
  
  }
  
  
  // Generates a version for the converted app using the current date. This isn't
  // really needed, but it seems like useful information.
  std::string ConvertTimeToExtensionVersion(const Time& create_time) {
    Time::Exploded create_time_exploded;
    create_time.UTCExplode(&create_time_exploded);
  
    double micros = static_cast<double>(
        (create_time_exploded.millisecond * Time::kMicrosecondsPerMillisecond) +
        (create_time_exploded.second * Time::kMicrosecondsPerSecond) +
        (create_time_exploded.minute * Time::kMicrosecondsPerMinute) +
        (create_time_exploded.hour * Time::kMicrosecondsPerHour));
    double day_fraction = micros / Time::kMicrosecondsPerDay;
    double stamp = day_fraction * std::numeric_limits<uint16>::max();
  
    // Ghetto-round, since VC++ doesn't have round().
    stamp = stamp >= (floor(stamp) + 0.5) ? (stamp + 1) : stamp;
  
    return base::StringPrintf("%i.%i.%i.%i",
                              create_time_exploded.year,
                              create_time_exploded.month,
                              create_time_exploded.day_of_month,
                              static_cast<uint16>(stamp));
  }
  
  scoped_refptr<Extension> ConvertWebAppToExtension(
      const WebApplicationInfo& web_app,
      const Time& create_time) {
    FilePath user_data_temp_dir = extension_file_util::GetUserDataTempDir();
    if (user_data_temp_dir.empty()) {
      LOG(ERROR) << "Could not get path to profile temporary directory.";
      return NULL;
    }
  
    ScopedTempDir temp_dir;
    if (!temp_dir.CreateUniqueTempDirUnderPath(user_data_temp_dir)) {
      LOG(ERROR) << "Could not create temporary directory.";
      return NULL;
    }
  
    // Create the manifest
    scoped_ptr<DictionaryValue> root(new DictionaryValue);
    root->SetString(keys::kPublicKey, GenerateKey(web_app.manifest_url));
    root->SetString(keys::kName, UTF16ToUTF8(web_app.title));
    root->SetString(keys::kVersion, ConvertTimeToExtensionVersion(create_time));
    root->SetString(keys::kDescription, UTF16ToUTF8(web_app.description));
    root->SetString(keys::kLaunchWebURL, web_app.app_url.spec());
  
    if (!web_app.launch_container.empty())
      root->SetString(keys::kLaunchContainer, web_app.launch_container);
  
    // Add the icons.
    DictionaryValue* icons = new DictionaryValue();
    root->Set(keys::kIcons, icons);
    for (size_t i = 0; i < web_app.icons.size(); ++i) {
      std::string size = StringPrintf("%i", web_app.icons[i].width);
      std::string icon_path = StringPrintf("%s/%s.png", kIconsDirName,
                                           size.c_str());
      icons->SetString(size, icon_path);
    }
  
    // Add the permissions.
    ListValue* permissions = new ListValue();
    root->Set(keys::kPermissions, permissions);
    for (size_t i = 0; i < web_app.permissions.size(); ++i) {
      permissions->Append(Value::CreateStringValue(web_app.permissions[i]));
    }
  
    // Add the URLs.
    ListValue* urls = new ListValue();
    root->Set(keys::kWebURLs, urls);
    for (size_t i = 0; i < web_app.urls.size(); ++i) {
      urls->Append(Value::CreateStringValue(web_app.urls[i].spec()));
    }
  
    // Write the manifest.
    FilePath manifest_path = temp_dir.path().Append(
        Extension::kManifestFilename);
    JSONFileValueSerializer serializer(manifest_path);
    if (!serializer.Serialize(*root)) {
      LOG(ERROR) << "Could not serialize manifest.";
      return NULL;
    }
  
    // Write the icon files.
    FilePath icons_dir = temp_dir.path().AppendASCII(kIconsDirName);
    if (!file_util::CreateDirectory(icons_dir)) {
      LOG(ERROR) << "Could not create icons directory.";
      return NULL;
    }
    for (size_t i = 0; i < web_app.icons.size(); ++i) {
      FilePath icon_file = icons_dir.AppendASCII(
          StringPrintf("%i.png", web_app.icons[i].width));
      std::vector<unsigned char> image_data;
      if (!gfx::PNGCodec::EncodeBGRASkBitmap(web_app.icons[i].data,
                                             false,
                                             &image_data)) {
        LOG(ERROR) << "Could not create icon file.";
        return NULL;
      }
  
      const char* image_data_ptr = reinterpret_cast<const char*>(&image_data[0]);
      if (!file_util::WriteFile(icon_file, image_data_ptr, image_data.size())) {
        LOG(ERROR) << "Could not write icon file.";
        return NULL;
      }
    }
  
    // Finally, create the extension object to represent the unpacked directory.
    std::string error;
    scoped_refptr<Extension> extension = Extension::Create(
        temp_dir.path(),
        Extension::INTERNAL,
        *root,
        Extension::STRICT_ERROR_CHECKS,
        &error);
    if (!extension) {
      LOG(ERROR) << error;
      return NULL;
    }
  
    temp_dir.Take();  // The caller takes ownership of the directory.
    return extension;
  }
  