path: root/chrome/browser/extensions/extension_prefs.cc

// 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/extension_prefs.h"

#include "base/string_number_conversions.h"
#include "base/string_util.h"
#include "base/utf_string_conversions.h"
#include "chrome/browser/extensions/extension_pref_store.h"
#include "chrome/browser/prefs/pref_notifier.h"
#include "chrome/browser/prefs/scoped_user_pref_update.h"
#include "chrome/common/chrome_notification_types.h"
#include "chrome/common/url_constants.h"
#include "chrome/common/extensions/extension.h"
#include "chrome/common/extensions/url_pattern.h"
#include "chrome/common/pref_names.h"
#include "content/common/notification_service.h"

using base::Time;

namespace {

// Additional preferences keys

// Where an extension was installed from. (see Extension::Location)
const char kPrefLocation[] = "location";

// Enabled, disabled, killed, etc. (see Extension::State)
const char kPrefState[] = "state";

// The path to the current version's manifest file.
const char kPrefPath[] = "path";

// The dictionary containing the extension's manifest.
const char kPrefManifest[] = "manifest";

// The version number.
const char kPrefVersion[] = "manifest.version";

// Indicates if an extension is blacklisted:
const char kPrefBlacklist[] = "blacklist";

// Indicates whether to show an install warning when the user enables.
const char kExtensionDidEscalatePermissions[] = "install_warning_on_enable";

// A preference that tracks browser action toolbar configuration. This is a list
// object stored in the Preferences file. The extensions are stored by ID.
const char kExtensionToolbar[] = "extensions.toolbar";

// The key for a serialized Time value indicating the start of the day (from the
// server's perspective) an extension last included a "ping" parameter during
// its update check.
const char kLastPingDay[] = "lastpingday";

// Similar to kLastPingDay, but for "active" instead of "rollcall" pings.
const char kLastActivePingDay[] = "last_active_pingday";

// A bit we use to keep track of whether we need to do an "active" ping.
const char kActiveBit[] = "active_bit";

// Path for settings specific to blacklist update.
const char kExtensionsBlacklistUpdate[] = "extensions.blacklistupdate";

// Path and sub-keys for the idle install info dictionary preference.
const char kIdleInstallInfo[] = "idle_install_info";
const char kIdleInstallInfoCrxPath[] = "crx_path";
const char kIdleInstallInfoVersion[] = "version";
const char kIdleInstallInfoFetchTime[] = "fetch_time";

// A preference that, if true, will allow this extension to run in incognito
// mode.
const char kPrefIncognitoEnabled[] = "incognito";

// A preference to control whether an extension is allowed to inject script in
// pages with file URLs.
const char kPrefAllowFileAccess[] = "allowFileAccess";

// A preference set by the web store to indicate login information for
// purchased apps.
const char kWebStoreLogin[] = "extensions.webstore_login";

// A preference set by the the NTP to persist the desired launch container type
// used for apps.
const char kPrefLaunchType[] = "launchType";

// A preference determining the order of which the apps appear on the NTP.
const char kPrefAppLaunchIndex[] = "app_launcher_index";

// A preference determining the page on which an app appears in the NTP.
const char kPrefPageIndex[] = "page_index";

// A preference specifying if the user dragged the app on the NTP.
const char kPrefUserDraggedApp[] = "user_dragged_app_ntp";

// A preference for storing extra data sent in update checks for an extension.
const char kUpdateUrlData[] = "update_url_data";

// Whether the browser action is visible in the toolbar.
const char kBrowserActionVisible[] = "browser_action_visible";

// Preferences that hold which permissions the user has granted the extension.
// We explicitly keep track of these so that extensions can contain unknown
// permissions, for backwards compatibility reasons, and we can still prompt
// the user to accept them once recognized.
const char kPrefGrantedAPIs[] = "granted_permissions.api";
const char kPrefGrantedExplicitHosts[] = "granted_permissions.explicit_host";
const char kPrefGrantedScriptableHosts[] =
    "granted_permissions.scriptable_host";

// The preference names for the old granted permissions scheme.
const char kPrefOldGrantedFullAccess[] = "granted_permissions.full";
const char kPrefOldGrantedHosts[] = "granted_permissions.host";
const char kPrefOldGrantedAPIs[] = "granted_permissions.api";

// A preference that indicates when an extension was installed.
const char kPrefInstallTime[] = "install_time";

// A preference that indicates whether the extension was installed from the
// Chrome Web Store.
const char kPrefFromWebStore[] = "from_webstore";

// A preference that indicates whether the extension was installed from a
// mock App created from a bookmark.
const char kPrefFromBookmark[] = "from_bookmark";

// A preference that contains any extension-controlled preferences.
const char kPrefPreferences[] = "preferences";

// A preference that contains any extension-controlled incognito preferences.
const char kPrefIncognitoPreferences[] = "incognito_preferences";

// A preference that contains extension-set content settings.
const char kPrefContentSettings[] = "content_settings";

// A preference that contains extension-set content settings.
const char kPrefIncognitoContentSettings[] = "incognito_content_settings";

// Provider of write access to a dictionary storing extension prefs.
class ScopedExtensionPrefUpdate : public DictionaryPrefUpdate {
 public:
  ScopedExtensionPrefUpdate(PrefService* service,
                            const std::string& extension_id) :
    DictionaryPrefUpdate(service, ExtensionPrefs::kExtensionsPref),
    prefs_(service),
    extension_id_(extension_id) {}

  virtual ~ScopedExtensionPrefUpdate() {
    prefs_->ScheduleSavePersistentPrefs();
  }

  virtual DictionaryValue* Get() {
    DictionaryValue* dict = DictionaryPrefUpdate::Get();
    DictionaryValue* extension = NULL;
    if (!dict->GetDictionary(extension_id_, &extension)) {
      // Extension pref does not exist, create it.
      extension = new DictionaryValue();
      dict->Set(extension_id_, extension);
    }
    return extension;
  }

 private:
  PrefService* prefs_;
  const std::string extension_id_;

  DISALLOW_COPY_AND_ASSIGN(ScopedExtensionPrefUpdate);
};

// Provider of write access to a dictionary storing extension controlled prefs.
class ScopedExtensionControlledPrefUpdate : public DictionaryPrefUpdate {
 public:
  // |incognito_or_regular_path| indicates the sub-path where the
  // extension controlled preferences are stored. This has to be either
  // kPrefPreferences or kPrefIncognitoPreferences.
  ScopedExtensionControlledPrefUpdate(
      PrefService* service,
      const std::string& extension_id,
      const std::string& incognito_or_regular_path) :
    DictionaryPrefUpdate(service, ExtensionPrefs::kExtensionsPref),
    prefs_(service),
    extension_id_(extension_id),
    incognito_or_regular_path_(incognito_or_regular_path) {}

  virtual ~ScopedExtensionControlledPrefUpdate() {
    prefs_->ScheduleSavePersistentPrefs();
  }

  virtual DictionaryValue* Get() {
    DictionaryValue* dict = DictionaryPrefUpdate::Get();
    DictionaryValue* preferences = NULL;
    std::string key =
        extension_id_ + std::string(".") + incognito_or_regular_path_;
    if (!dict->GetDictionary(key, &preferences)) {
      preferences = new DictionaryValue;
      dict->Set(key, preferences);
    }
    return preferences;
  }

 private:
  PrefService* prefs_;
  const std::string extension_id_;
  const std::string incognito_or_regular_path_;

  DISALLOW_COPY_AND_ASSIGN(ScopedExtensionControlledPrefUpdate);
};

}  // namespace

ExtensionPrefs::ExtensionPrefs(
    PrefService* prefs,
    const FilePath& root_dir,
    ExtensionPrefValueMap* extension_pref_value_map)
    : prefs_(prefs),
      install_directory_(root_dir),
      extension_pref_value_map_(extension_pref_value_map),
      content_settings_store_(new ExtensionContentSettingsStore()) {
  MakePathsRelative();

  InitPrefStore();

  content_settings_store_->AddObserver(this);
}

ExtensionPrefs::~ExtensionPrefs() {
}

// static
const char ExtensionPrefs::kExtensionsPref[] = "extensions.settings";

static FilePath::StringType MakePathRelative(const FilePath& parent,
                                             const FilePath& child) {
  if (!parent.IsParent(child))
    return child.value();

  FilePath::StringType retval = child.value().substr(
      parent.value().length());
  if (FilePath::IsSeparator(retval[0]))
    return retval.substr(1);
  else
    return retval;
}

void ExtensionPrefs::MakePathsRelative() {
  const DictionaryValue* dict = prefs_->GetDictionary(kExtensionsPref);
  if (!dict || dict->empty())
    return;

  // Collect all extensions ids with absolute paths in |absolute_keys|.
  std::set<std::string> absolute_keys;
  for (DictionaryValue::key_iterator i = dict->begin_keys();
       i != dict->end_keys(); ++i) {
    DictionaryValue* extension_dict = NULL;
    if (!dict->GetDictionaryWithoutPathExpansion(*i, &extension_dict))
      continue;
    int location_value;
    if (extension_dict->GetInteger(kPrefLocation, &location_value) &&
        location_value == Extension::LOAD) {
      // Unpacked extensions can have absolute paths.
      continue;
    }
    FilePath::StringType path_string;
    if (!extension_dict->GetString(kPrefPath, &path_string))
      continue;
    FilePath path(path_string);
    if (path.IsAbsolute())
      absolute_keys.insert(*i);
  }
  if (absolute_keys.empty())
    return;

  // Fix these paths.
  DictionaryPrefUpdate update(prefs_, kExtensionsPref);
  const DictionaryValue* update_dict = update.Get();
  for (std::set<std::string>::iterator i = absolute_keys.begin();
       i != absolute_keys.end(); ++i) {
    DictionaryValue* extension_dict = NULL;
    if (!update_dict->GetDictionaryWithoutPathExpansion(*i, &extension_dict)) {
      NOTREACHED() << "Control should never reach here for extension " << *i;
      continue;
    }
    FilePath::StringType path_string;
    extension_dict->GetString(kPrefPath, &path_string);
    FilePath path(path_string);
    extension_dict->SetString(kPrefPath,
        MakePathRelative(install_directory_, path));
  }
  SavePrefs();
}

void ExtensionPrefs::MakePathsAbsolute(DictionaryValue* dict) {
  if (!dict || dict->empty())
    return;

  for (DictionaryValue::key_iterator i = dict->begin_keys();
       i != dict->end_keys(); ++i) {
    DictionaryValue* extension_dict = NULL;
    if (!dict->GetDictionaryWithoutPathExpansion(*i, &extension_dict)) {
      NOTREACHED();
      continue;
    }

    int location_value;
    if (extension_dict->GetInteger(kPrefLocation, &location_value) &&
        location_value == Extension::LOAD) {
      // Unpacked extensions will already have absolute paths.
      continue;
    }

    FilePath::StringType path_string;
    if (!extension_dict->GetString(kPrefPath, &path_string))
      continue;

    DCHECK(!FilePath(path_string).IsAbsolute());
    extension_dict->SetString(
        kPrefPath, install_directory_.Append(path_string).value());
  }
}

DictionaryValue* ExtensionPrefs::CopyCurrentExtensions() {
  const DictionaryValue* extensions = prefs_->GetDictionary(kExtensionsPref);
  if (extensions) {
    DictionaryValue* copy = extensions->DeepCopy();
    MakePathsAbsolute(copy);
    return copy;
  }
  return new DictionaryValue;
}

// static
bool ExtensionPrefs::ReadBooleanFromPref(
    const DictionaryValue* ext, const std::string& pref_key) {
  bool bool_value = false;
  ext->GetBoolean(pref_key, &bool_value);
  return bool_value;
}

bool ExtensionPrefs::ReadExtensionPrefBoolean(
    const std::string& extension_id, const std::string& pref_key) {
  const DictionaryValue* ext = GetExtensionPref(extension_id);
  if (!ext) {
    // No such extension yet.
    return false;
  }
  return ReadBooleanFromPref(ext, pref_key);
}

// static
bool ExtensionPrefs::ReadIntegerFromPref(
    const DictionaryValue* ext, const std::string& pref_key, int* out_value) {
  if (!ext->GetInteger(pref_key, out_value))
    return false;

  return out_value != NULL;
}

bool ExtensionPrefs::ReadExtensionPrefInteger(
    const std::string& extension_id, const std::string& pref_key,
    int* out_value) {
  const DictionaryValue* ext = GetExtensionPref(extension_id);
  if (!ext) {
    // No such extension yet.
    return false;
  }
  return ReadIntegerFromPref(ext, pref_key, out_value);
}

bool ExtensionPrefs::ReadExtensionPrefList(
    const std::string& extension_id, const std::string& pref_key,
    const ListValue** out_value) {
  const DictionaryValue* ext = GetExtensionPref(extension_id);
  ListValue* out = NULL;
  if (!ext || !ext->GetList(pref_key, &out))
    return false;
  if (out_value)
    *out_value = out;

  return true;
}

bool ExtensionPrefs::ReadExtensionPrefURLPatternSet(
    const std::string& extension_id,
    const std::string& pref_key,
    URLPatternSet* result,
    int valid_schemes) {
  const ListValue* value = NULL;
  if (!ReadExtensionPrefList(extension_id, pref_key, &value))
    return false;

  result->ClearPatterns();
  bool allow_file_access = AllowFileAccess(extension_id);

  for (size_t i = 0; i < value->GetSize(); ++i) {
    std::string item;
    if (!value->GetString(i, &item))
      return false;
    URLPattern pattern(valid_schemes);
    if (pattern.Parse(item, URLPattern::IGNORE_PORTS) !=
        URLPattern::PARSE_SUCCESS) {
      NOTREACHED();
      return false;
    }
    if (!allow_file_access && pattern.MatchesScheme(chrome::kFileScheme)) {
      pattern.SetValidSchemes(
          pattern.valid_schemes() & ~URLPattern::SCHEME_FILE);
    }
    result->AddPattern(pattern);
  }

  return true;
}

void ExtensionPrefs::SetExtensionPrefURLPatternSet(
    const std::string& extension_id,
    const std::string& pref_key,
    const URLPatternSet& new_value) {
  ListValue* value = new ListValue();
  for (URLPatternSet::const_iterator i = new_value.begin();
       i != new_value.end(); ++i)
    value->AppendIfNotPresent(Value::CreateStringValue(i->GetAsString()));

  UpdateExtensionPref(extension_id, pref_key, value);
}

void ExtensionPrefs::SavePrefs() {
  prefs_->ScheduleSavePersistentPrefs();
}

// static
bool ExtensionPrefs::IsBlacklistBitSet(DictionaryValue* ext) {
  return ReadBooleanFromPref(ext, kPrefBlacklist);
}

bool ExtensionPrefs::IsExtensionBlacklisted(const std::string& extension_id) {
  return ReadExtensionPrefBoolean(extension_id, kPrefBlacklist);
}

bool ExtensionPrefs::IsExtensionAllowedByPolicy(
    const std::string& extension_id) {
  std::string string_value;

  const ListValue* blacklist =
      prefs_->GetList(prefs::kExtensionInstallDenyList);
  if (!blacklist || blacklist->empty())
    return true;

  // Check the whitelist first.
  const ListValue* whitelist =
      prefs_->GetList(prefs::kExtensionInstallAllowList);
  if (whitelist) {
    for (ListValue::const_iterator it = whitelist->begin();
         it != whitelist->end(); ++it) {
      if (!(*it)->GetAsString(&string_value))
        LOG(WARNING) << "Failed to read whitelist string.";
      else if (string_value == extension_id)
        return true;
    }
  }

  // Then check the blacklist (the admin blacklist, not the Google blacklist).
  if (blacklist) {
    for (ListValue::const_iterator it = blacklist->begin();
         it != blacklist->end(); ++it) {
      if (!(*it)->GetAsString(&string_value)) {
        LOG(WARNING) << "Failed to read blacklist string.";
      } else {
        if (string_value == "*")
          return false;  // Only whitelisted extensions are allowed.
        if (string_value == extension_id)
          return false;
      }
    }
  }

  return true;
}

bool ExtensionPrefs::DidExtensionEscalatePermissions(
    const std::string& extension_id) {
  return ReadExtensionPrefBoolean(extension_id,
                                  kExtensionDidEscalatePermissions);
}

void ExtensionPrefs::SetDidExtensionEscalatePermissions(
    const Extension* extension, bool did_escalate) {
  UpdateExtensionPref(extension->id(), kExtensionDidEscalatePermissions,
                      Value::CreateBooleanValue(did_escalate));
}

void ExtensionPrefs::UpdateBlacklist(
    const std::set<std::string>& blacklist_set) {
  std::vector<std::string> remove_pref_ids;
  std::set<std::string> used_id_set;
  const DictionaryValue* extensions = prefs_->GetDictionary(kExtensionsPref);

  if (extensions) {
    for (DictionaryValue::key_iterator extension_id = extensions->begin_keys();
         extension_id != extensions->end_keys(); ++extension_id) {
      DictionaryValue* ext;
      if (!extensions->GetDictionaryWithoutPathExpansion(*extension_id, &ext)) {
        NOTREACHED() << "Invalid pref for extension " << *extension_id;
        continue;
      }
      const std::string& id(*extension_id);
      if (blacklist_set.find(id) == blacklist_set.end()) {
        if (!IsBlacklistBitSet(ext)) {
          // This extension is not in blacklist. And it was not blacklisted
          // before.
          continue;
        } else {
          if (ext->size() == 1) {
            // We should remove the entry if the only flag here is blacklist.
            remove_pref_ids.push_back(id);
          } else {
            // Remove the blacklist bit.
            ext->Remove(kPrefBlacklist, NULL);
          }
        }
      } else {
        if (!IsBlacklistBitSet(ext)) {
          // Only set the blacklist if it was not set.
          ext->SetBoolean(kPrefBlacklist, true);
        }
        // Keep the record if this extension is already processed.
        used_id_set.insert(id);
      }
    }
  }

  // Iterate the leftovers to set blacklist in pref
  std::set<std::string>::const_iterator set_itr = blacklist_set.begin();
  for (; set_itr != blacklist_set.end(); ++set_itr) {
    if (used_id_set.find(*set_itr) == used_id_set.end()) {
      UpdateExtensionPref(*set_itr, kPrefBlacklist,
                          Value::CreateBooleanValue(true));
    }
  }
  for (unsigned int i = 0; i < remove_pref_ids.size(); ++i) {
    DeleteExtensionPrefs(remove_pref_ids[i]);
  }
}

namespace {

// Serializes |time| as a string value mapped to |key| in |dictionary|.
void SaveTime(DictionaryValue* dictionary, const char* key, const Time& time) {
  if (!dictionary)
    return;
  std::string string_value = base::Int64ToString(time.ToInternalValue());
  dictionary->SetString(key, string_value);
}

// The opposite of SaveTime. If |key| is not found, this returns an empty Time
// (is_null() will return true).
Time ReadTime(const DictionaryValue* dictionary, const char* key) {
  if (!dictionary)
    return Time();
  std::string string_value;
  int64 value;
  if (dictionary->GetString(key, &string_value)) {
    if (base::StringToInt64(string_value, &value)) {
      return Time::FromInternalValue(value);
    }
  }
  return Time();
}

}  // namespace

Time ExtensionPrefs::LastPingDay(const std::string& extension_id) const {
  DCHECK(Extension::IdIsValid(extension_id));
  return ReadTime(GetExtensionPref(extension_id), kLastPingDay);
}

void ExtensionPrefs::SetLastPingDay(const std::string& extension_id,
                                    const Time& time) {
  DCHECK(Extension::IdIsValid(extension_id));
  ScopedExtensionPrefUpdate update(prefs_, extension_id);
  SaveTime(update.Get(), kLastPingDay, time);
}

Time ExtensionPrefs::BlacklistLastPingDay() const {
  return ReadTime(prefs_->GetDictionary(kExtensionsBlacklistUpdate),
                  kLastPingDay);
}

void ExtensionPrefs::SetBlacklistLastPingDay(const Time& time) {
  DictionaryPrefUpdate update(prefs_, kExtensionsBlacklistUpdate);
  SaveTime(update.Get(), kLastPingDay, time);
}

Time ExtensionPrefs::LastActivePingDay(const std::string& extension_id) {
  DCHECK(Extension::IdIsValid(extension_id));
  return ReadTime(GetExtensionPref(extension_id), kLastActivePingDay);
}

void ExtensionPrefs::SetLastActivePingDay(const std::string& extension_id,
                                          const base::Time& time) {
  DCHECK(Extension::IdIsValid(extension_id));
  ScopedExtensionPrefUpdate update(prefs_, extension_id);
  SaveTime(update.Get(), kLastActivePingDay, time);
}

bool ExtensionPrefs::GetActiveBit(const std::string& extension_id) {
  const DictionaryValue* dictionary = GetExtensionPref(extension_id);
  bool result = false;
  if (dictionary && dictionary->GetBoolean(kActiveBit, &result))
    return result;
  return false;
}

void ExtensionPrefs::SetActiveBit(const std::string& extension_id,
                                  bool active) {
  UpdateExtensionPref(extension_id, kActiveBit,
                      Value::CreateBooleanValue(active));
}

void ExtensionPrefs::MigratePermissions(const ExtensionIdSet& extension_ids) {
  ExtensionPermissionsInfo* info = ExtensionPermissionsInfo::GetInstance();
  for (ExtensionIdSet::const_iterator ext_id = extension_ids.begin();
       ext_id != extension_ids.end(); ++ext_id) {

    // An extension's granted permissions need to be migrated if the
    // full_access bit is present. This bit was always present in the previous
    // scheme and is never present now.
    bool full_access;
    const DictionaryValue* ext = GetExtensionPref(*ext_id);
    if (!ext || !ext->GetBoolean(kPrefOldGrantedFullAccess, &full_access))
      continue;

    // Remove the full access bit (empty list will get trimmed).
    UpdateExtensionPref(
        *ext_id, kPrefOldGrantedFullAccess, new ListValue());

    // Add the plugin permission if the full access bit was set.
    if (full_access) {
      ListValue* apis = NULL;
      ListValue* new_apis = NULL;

      if (ext->GetList(kPrefGrantedAPIs, &apis))
        new_apis = apis->DeepCopy();
      else
        new_apis = new ListValue();

      std::string plugin_name = info->GetByID(
          ExtensionAPIPermission::kPlugin)->name();
      new_apis->Append(Value::CreateStringValue(plugin_name));
      UpdateExtensionPref(*ext_id, kPrefGrantedAPIs, new_apis);
    }

    // The granted permissions originally only held the effective hosts,
    // which are a combination of host and user script host permissions.
    // We now maintain these lists separately. For migration purposes, it
    // does not matter how we treat the old effective hosts as long as the
    // new effective hosts will be the same, so we move them to explicit
    // host permissions.
    ListValue* hosts;
    if (ext->GetList(kPrefOldGrantedHosts, &hosts)) {
      UpdateExtensionPref(
          *ext_id, kPrefGrantedExplicitHosts, hosts->DeepCopy());

      // We can get rid of the old one by setting it to an empty list.
      UpdateExtensionPref(*ext_id, kPrefOldGrantedHosts, new ListValue());
    }
  }
}

ExtensionPermissionSet* ExtensionPrefs::GetGrantedPermissions(
    const std::string& extension_id) {
  CHECK(Extension::IdIsValid(extension_id));

  const DictionaryValue* ext = GetExtensionPref(extension_id);
  if (!ext)
    return NULL;

  // Retrieve the API permissions.
  ExtensionAPIPermissionSet apis;
  const ListValue* api_values = NULL;
  if (ReadExtensionPrefList(extension_id, kPrefGrantedAPIs, &api_values)) {
    ExtensionPermissionsInfo* info = ExtensionPermissionsInfo::GetInstance();
    for (size_t i = 0; i < api_values->GetSize(); ++i) {
      std::string permission_name;
      if (api_values->GetString(i, &permission_name)) {
        ExtensionAPIPermission *permission = info->GetByName(permission_name);
        if (permission)
          apis.insert(permission->id());
      }
    }
  }

  // Retrieve the explicit host permissions.
  URLPatternSet explicit_hosts;
  ReadExtensionPrefURLPatternSet(
      extension_id, kPrefGrantedExplicitHosts,
      &explicit_hosts, Extension::kValidHostPermissionSchemes);

  // Retrieve the scriptable host permissions.
  URLPatternSet scriptable_hosts;
  ReadExtensionPrefURLPatternSet(
      extension_id, kPrefGrantedScriptableHosts,
      &scriptable_hosts, UserScript::kValidUserScriptSchemes);

  return new ExtensionPermissionSet(apis, explicit_hosts, scriptable_hosts);
}

void ExtensionPrefs::AddGrantedPermissions(
    const std::string& extension_id,
    const ExtensionPermissionSet* permissions) {
  CHECK(Extension::IdIsValid(extension_id));

  scoped_ptr<ExtensionPermissionSet> granted_permissions(
      GetGrantedPermissions(extension_id));

  // The new granted permissions are the union of the already granted
  // permissions and the newly granted permissions.
  scoped_ptr<ExtensionPermissionSet> new_perms(
      ExtensionPermissionSet::CreateUnion(
          permissions, granted_permissions.get()));

  // Set the API permissions.
  ListValue* api_values = new ListValue();
  ExtensionAPIPermissionSet apis = new_perms->apis();
  ExtensionPermissionsInfo* info = ExtensionPermissionsInfo::GetInstance();
  for (ExtensionAPIPermissionSet::const_iterator i = apis.begin();
       i != apis.end(); ++i) {
    ExtensionAPIPermission* perm = info->GetByID(*i);
    if (perm)
      api_values->Append(Value::CreateStringValue(perm->name()));
  }
  UpdateExtensionPref(extension_id, kPrefGrantedAPIs, api_values);

  // Set the explicit host permissions.
  if (!new_perms->explicit_hosts().is_empty()) {
    SetExtensionPrefURLPatternSet(extension_id,
                                  kPrefGrantedExplicitHosts,
                                  new_perms->explicit_hosts());
  }

  // Set the scriptable host permissions.
  if (!new_perms->scriptable_hosts().is_empty()) {
    SetExtensionPrefURLPatternSet(extension_id,
                                  kPrefGrantedScriptableHosts,
                                  new_perms->scriptable_hosts());
  }
}

bool ExtensionPrefs::IsIncognitoEnabled(const std::string& extension_id) {
  return ReadExtensionPrefBoolean(extension_id, kPrefIncognitoEnabled);
}

void ExtensionPrefs::SetIsIncognitoEnabled(const std::string& extension_id,
                                           bool enabled) {
  UpdateExtensionPref(extension_id, kPrefIncognitoEnabled,
                      Value::CreateBooleanValue(enabled));
}

bool ExtensionPrefs::AllowFileAccess(const std::string& extension_id) {
  return ReadExtensionPrefBoolean(extension_id, kPrefAllowFileAccess);
}

void ExtensionPrefs::SetAllowFileAccess(const std::string& extension_id,
                                        bool allow) {
  UpdateExtensionPref(extension_id, kPrefAllowFileAccess,
                      Value::CreateBooleanValue(allow));
}

bool ExtensionPrefs::HasAllowFileAccessSetting(
    const std::string& extension_id) const {
  const DictionaryValue* ext = GetExtensionPref(extension_id);
  return ext && ext->HasKey(kPrefAllowFileAccess);
}

ExtensionPrefs::LaunchType ExtensionPrefs::GetLaunchType(
    const std::string& extension_id,
    ExtensionPrefs::LaunchType default_pref_value) {
  int value = -1;
  LaunchType result = LAUNCH_REGULAR;

  if (ReadExtensionPrefInteger(extension_id, kPrefLaunchType, &value) &&
     (value == LAUNCH_PINNED ||
      value == LAUNCH_REGULAR ||
      value == LAUNCH_FULLSCREEN ||
      value == LAUNCH_WINDOW)) {
    result = static_cast<LaunchType>(value);
  } else {
    result = default_pref_value;
  }
  #if defined(OS_MACOSX)
    // App windows are not yet supported on mac.  Pref sync could make
    // the launch type LAUNCH_WINDOW, even if there is no UI to set it
    // on mac.
    if (result == LAUNCH_WINDOW)
      result = LAUNCH_REGULAR;
  #endif

  return result;
}

extension_misc::LaunchContainer ExtensionPrefs::GetLaunchContainer(
    const Extension* extension,
    ExtensionPrefs::LaunchType default_pref_value) {
  extension_misc::LaunchContainer manifest_launch_container =
      extension->launch_container();

  const extension_misc::LaunchContainer kInvalidLaunchContainer =
      static_cast<extension_misc::LaunchContainer>(-1);

  extension_misc::LaunchContainer result = kInvalidLaunchContainer;

  if (manifest_launch_container == extension_misc::LAUNCH_PANEL) {
    // Apps with app.launch.container = 'panel' should always
    // open in a panel.
    result = extension_misc::LAUNCH_PANEL;

  } else if (manifest_launch_container == extension_misc::LAUNCH_TAB) {
    // Look for prefs that indicate the user's choice of launch
    // container.  The app's menu on the NTP provides a UI to set
    // this preference.  If no preference is set, |default_pref_value|
    // is used.
    ExtensionPrefs::LaunchType prefs_launch_type =
        GetLaunchType(extension->id(), default_pref_value);

    if (prefs_launch_type == ExtensionPrefs::LAUNCH_WINDOW) {
      // If the pref is set to launch a window (or no pref is set, and
      // window opening is the default), make the container a window.
      result = extension_misc::LAUNCH_WINDOW;

    } else {
      // All other launch types (tab, pinned, fullscreen) are
      // implemented as tabs in a window.
      result = extension_misc::LAUNCH_TAB;
    }
  } else {
    // If a new value for app.launch.container is added, logic
    // for it should be added here.  extension_misc::LAUNCH_WINDOW
    // is not present because there is no way to set it in a manifest.
    NOTREACHED() << manifest_launch_container;
  }

  // All paths should set |result|.
  if (result == kInvalidLaunchContainer) {
    DLOG(FATAL) << "Failed to set a launch container.";
    result = extension_misc::LAUNCH_TAB;
  }

  return result;
}

void ExtensionPrefs::SetLaunchType(const std::string& extension_id,
                                   LaunchType launch_type) {
  UpdateExtensionPref(extension_id, kPrefLaunchType,
      Value::CreateIntegerValue(static_cast<int>(launch_type)));
}

bool ExtensionPrefs::IsExternalExtensionUninstalled(
    const std::string& id) const {
  const DictionaryValue* extension = GetExtensionPref(id);
  if (!extension)
    return false;
  int state = 0;
  return extension->GetInteger(kPrefState, &state) &&
         state == static_cast<int>(Extension::EXTERNAL_EXTENSION_UNINSTALLED);
}

std::vector<std::string> ExtensionPrefs::GetToolbarOrder() {
  ExtensionPrefs::ExtensionIdSet extension_ids;
  const ListValue* toolbar_order = prefs_->GetList(kExtensionToolbar);
  if (toolbar_order) {
    for (size_t i = 0; i < toolbar_order->GetSize(); ++i) {
      std::string extension_id;
      if (toolbar_order->GetString(i, &extension_id))
        extension_ids.push_back(extension_id);
    }
  }
  return extension_ids;
}

void ExtensionPrefs::SetToolbarOrder(
    const std::vector<std::string>& extension_ids) {
  ListPrefUpdate update(prefs_, kExtensionToolbar);
  ListValue* toolbar_order = update.Get();
  toolbar_order->Clear();
  for (std::vector<std::string>::const_iterator iter = extension_ids.begin();
       iter != extension_ids.end(); ++iter) {
    toolbar_order->Append(new StringValue(*iter));
  }
  SavePrefs();
}

void ExtensionPrefs::OnExtensionInstalled(
    const Extension* extension,
    Extension::State initial_state,
    bool from_webstore) {
  const std::string& id = extension->id();
  CHECK(Extension::IdIsValid(id));
  ScopedExtensionPrefUpdate update(prefs_, id);
  DictionaryValue* extension_dict = update.Get();
  const base::Time install_time = GetCurrentTime();
  extension_dict->Set(kPrefState, Value::CreateIntegerValue(initial_state));
  extension_dict->Set(kPrefLocation,
                      Value::CreateIntegerValue(extension->location()));
  extension_dict->Set(kPrefFromWebStore,
                      Value::CreateBooleanValue(from_webstore));
  extension_dict->Set(kPrefFromBookmark,
                      Value::CreateBooleanValue(extension->from_bookmark()));
  extension_dict->Set(kPrefInstallTime,
                      Value::CreateStringValue(
                          base::Int64ToString(install_time.ToInternalValue())));
  extension_dict->Set(kPrefPreferences, new DictionaryValue());
  extension_dict->Set(kPrefIncognitoPreferences, new DictionaryValue());
  extension_dict->Set(kPrefContentSettings, new ListValue());
  extension_dict->Set(kPrefIncognitoContentSettings, new ListValue());

  FilePath::StringType path = MakePathRelative(install_directory_,
      extension->path());
  extension_dict->Set(kPrefPath, Value::CreateStringValue(path));
  // We store prefs about LOAD extensions, but don't cache their manifest
  // since it may change on disk.
  if (extension->location() != Extension::LOAD) {
    extension_dict->Set(kPrefManifest,
                        extension->manifest_value()->DeepCopy());
  }
  extension_dict->Set(kPrefAppLaunchIndex,
                      Value::CreateIntegerValue(GetNextAppLaunchIndex()));
  extension_pref_value_map_->RegisterExtension(
      id, install_time, initial_state == Extension::ENABLED);
  content_settings_store_->RegisterExtension(
      id, install_time, initial_state == Extension::ENABLED);
}

void ExtensionPrefs::OnExtensionUninstalled(const std::string& extension_id,
                                            const Extension::Location& location,
                                            bool external_uninstall) {
  // For external extensions, we save a preference reminding ourself not to try
  // and install the extension anymore (except when |external_uninstall| is
  // true, which signifies that the registry key was deleted or the pref file
  // no longer lists the extension).
  if (!external_uninstall && Extension::IsExternalLocation(location)) {
    UpdateExtensionPref(extension_id, kPrefState,
                        Value::CreateIntegerValue(
                            Extension::EXTERNAL_EXTENSION_UNINSTALLED));
    extension_pref_value_map_->SetExtensionState(extension_id, false);
    content_settings_store_->SetExtensionState(extension_id, false);
  } else {
    DeleteExtensionPrefs(extension_id);
  }
}

Extension::State ExtensionPrefs::GetExtensionState(
    const std::string& extension_id) const {
  const DictionaryValue* extension = GetExtensionPref(extension_id);

  int state = -1;
  if (!extension || !extension->GetInteger(kPrefState, &state) ||
      state < 0 || state >= Extension::NUM_STATES) {
    LOG(ERROR) << "Bad or missing pref 'state' for extension '"
               << extension_id << "'";
    return Extension::ENABLED;
  }
  return static_cast<Extension::State>(state);
}

void ExtensionPrefs::SetExtensionState(const std::string& extension_id,
                                       Extension::State state) {
  UpdateExtensionPref(extension_id, kPrefState,
                      Value::CreateIntegerValue(state));
  bool enabled = (state == Extension::ENABLED);
  extension_pref_value_map_->SetExtensionState(extension_id, enabled);
  content_settings_store_->SetExtensionState(extension_id, enabled);
}

bool ExtensionPrefs::GetBrowserActionVisibility(const Extension* extension) {
  const DictionaryValue* extension_prefs = GetExtensionPref(extension->id());
  if (!extension_prefs)
    return true;
  bool visible = false;
  if (!extension_prefs->GetBoolean(kBrowserActionVisible, &visible) || visible)
    return true;

  return false;
}

void ExtensionPrefs::SetBrowserActionVisibility(const Extension* extension,
                                                bool visible) {
  if (GetBrowserActionVisibility(extension) == visible)
    return;

  UpdateExtensionPref(extension->id(), kBrowserActionVisible,
                      Value::CreateBooleanValue(visible));
  NotificationService::current()->Notify(
      chrome::NOTIFICATION_EXTENSION_BROWSER_ACTION_VISIBILITY_CHANGED,
      Source<ExtensionPrefs>(this),
      Details<const Extension>(extension));
}

std::string ExtensionPrefs::GetVersionString(const std::string& extension_id) {
  const DictionaryValue* extension = GetExtensionPref(extension_id);
  if (!extension)
    return std::string();

  std::string version;
  if (!extension->GetString(kPrefVersion, &version)) {
    LOG(ERROR) << "Bad or missing pref 'version' for extension '"
               << extension_id << "'";
  }

  return version;
}

void ExtensionPrefs::UpdateManifest(const Extension* extension) {
  if (extension->location() != Extension::LOAD) {
    const DictionaryValue* extension_dict = GetExtensionPref(extension->id());
    if (!extension_dict)
      return;
    DictionaryValue* old_manifest = NULL;
    bool update_required =
        !extension_dict->GetDictionary(kPrefManifest, &old_manifest) ||
        !extension->manifest_value()->Equals(old_manifest);
    if (update_required) {
      UpdateExtensionPref(extension->id(), kPrefManifest,
                          extension->manifest_value()->DeepCopy());
    }
  }
}

FilePath ExtensionPrefs::GetExtensionPath(const std::string& extension_id) {
  const DictionaryValue* dict = GetExtensionPref(extension_id);
  if (!dict)
    return FilePath();

  std::string path;
  if (!dict->GetString(kPrefPath, &path))
    return FilePath();

  return install_directory_.Append(FilePath::FromWStringHack(UTF8ToWide(path)));
}

void ExtensionPrefs::UpdateExtensionPref(const std::string& extension_id,
                                         const std::string& key,
                                         Value* data_value) {
  if (!Extension::IdIsValid(extension_id)) {
    NOTREACHED() << "Invalid extension_id " << extension_id;
    return;
  }
  ScopedExtensionPrefUpdate update(prefs_, extension_id);
  update->Set(key, data_value);
}

void ExtensionPrefs::DeleteExtensionPrefs(const std::string& extension_id) {
  DictionaryPrefUpdate update(prefs_, kExtensionsPref);
  DictionaryValue* dict = update.Get();
  if (dict->HasKey(extension_id)) {
    dict->Remove(extension_id, NULL);
    SavePrefs();
  }
  extension_pref_value_map_->UnregisterExtension(extension_id);
  content_settings_store_->UnregisterExtension(extension_id);
}

const DictionaryValue* ExtensionPrefs::GetExtensionPref(
    const std::string& extension_id) const {
  const DictionaryValue* dict = prefs_->GetDictionary(kExtensionsPref);
  if (!dict)
    return NULL;
  DictionaryValue* extension = NULL;
  dict->GetDictionary(extension_id, &extension);
  return extension;
}

// Helper function for GetInstalledExtensionsInfo.
static ExtensionInfo* GetInstalledExtensionInfoImpl(
    DictionaryValue* extension_data,
    DictionaryValue::key_iterator extension_id) {
  DictionaryValue* ext;
  if (!extension_data->GetDictionaryWithoutPathExpansion(*extension_id, &ext)) {
    LOG(WARNING) << "Invalid pref for extension " << *extension_id;
    NOTREACHED();
    return NULL;
  }
  if (ext->HasKey(kPrefBlacklist)) {
    bool is_blacklisted = false;
    if (!ext->GetBoolean(kPrefBlacklist, &is_blacklisted)) {
      NOTREACHED() << "Invalid blacklist pref:" << *extension_id;
      return NULL;
    }
    if (is_blacklisted) {
      return NULL;
    }
  }
  int state_value;
  if (!ext->GetInteger(kPrefState, &state_value)) {
    // This can legitimately happen if we store preferences for component
    // extensions.
    return NULL;
  }
  if (state_value == Extension::EXTERNAL_EXTENSION_UNINSTALLED) {
    LOG(WARNING) << "External extension with id " << *extension_id
                 << " has been uninstalled by the user";
    return NULL;
  }
  FilePath::StringType path;
  if (!ext->GetString(kPrefPath, &path)) {
    return NULL;
  }
  int location_value;
  if (!ext->GetInteger(kPrefLocation, &location_value)) {
    return NULL;
  }

  // Only the following extension types can be installed permanently in the
  // preferences.
  Extension::Location location =
      static_cast<Extension::Location>(location_value);
  if (location != Extension::INTERNAL &&
      location != Extension::LOAD &&
      !Extension::IsExternalLocation(location)) {
    NOTREACHED();
    return NULL;
  }

  DictionaryValue* manifest = NULL;
  if (location != Extension::LOAD &&
      !ext->GetDictionary(kPrefManifest, &manifest)) {
    LOG(WARNING) << "Missing manifest for extension " << *extension_id;
    // Just a warning for now.
  }

  return new ExtensionInfo(manifest, *extension_id, FilePath(path), location);
}

ExtensionPrefs::ExtensionsInfo* ExtensionPrefs::GetInstalledExtensionsInfo() {
  scoped_ptr<DictionaryValue> extension_data(CopyCurrentExtensions());

  ExtensionsInfo* extensions_info = new ExtensionsInfo;

  for (DictionaryValue::key_iterator extension_id(
           extension_data->begin_keys());
       extension_id != extension_data->end_keys(); ++extension_id) {
    if (!Extension::IdIsValid(*extension_id))
      continue;

    ExtensionInfo* info = GetInstalledExtensionInfoImpl(extension_data.get(),
                                                        extension_id);
    if (info)
      extensions_info->push_back(linked_ptr<ExtensionInfo>(info));
  }

  return extensions_info;
}

ExtensionInfo* ExtensionPrefs::GetInstalledExtensionInfo(
    const std::string& extension_id) {
  scoped_ptr<DictionaryValue> extension_data(CopyCurrentExtensions());

  for (DictionaryValue::key_iterator extension_iter(
           extension_data->begin_keys());
       extension_iter != extension_data->end_keys(); ++extension_iter) {
    if (*extension_iter == extension_id) {
      return GetInstalledExtensionInfoImpl(extension_data.get(),
                                           extension_iter);
    }
  }

  return NULL;
}

void ExtensionPrefs::SetIdleInstallInfo(const std::string& extension_id,
                                        const FilePath& crx_path,
                                        const std::string& version,
                                        const base::Time& fetch_time) {
  DictionaryValue* info = new DictionaryValue();
  info->SetString(kIdleInstallInfoCrxPath, crx_path.value());
  info->SetString(kIdleInstallInfoVersion, version);
  info->SetString(kIdleInstallInfoFetchTime,
                  base::Int64ToString(fetch_time.ToInternalValue()));
  UpdateExtensionPref(extension_id, kIdleInstallInfo, info);
}

bool ExtensionPrefs::RemoveIdleInstallInfo(const std::string& extension_id) {
  if (!GetExtensionPref(extension_id))
    return false;
  ScopedExtensionPrefUpdate update(prefs_, extension_id);
  bool result = update->Remove(kIdleInstallInfo, NULL);
  return result;
}

bool ExtensionPrefs::GetIdleInstallInfo(const std::string& extension_id,
                                        FilePath* crx_path,
                                        std::string* version,
                                        base::Time* fetch_time) {
  const DictionaryValue* extension_prefs = GetExtensionPref(extension_id);
  if (!extension_prefs)
    return false;

  // Do all the reads from the prefs together, and don't do any assignment
  // to the out parameters unless all the reads succeed.
  DictionaryValue* info = NULL;
  if (!extension_prefs->GetDictionary(kIdleInstallInfo, &info))
    return false;

  FilePath::StringType path_string;
  if (!info->GetString(kIdleInstallInfoCrxPath, &path_string))
    return false;

  std::string tmp_version;
  if (!info->GetString(kIdleInstallInfoVersion, &tmp_version))
    return false;

  std::string fetch_time_string;
  if (!info->GetString(kIdleInstallInfoFetchTime, &fetch_time_string))
    return false;

  int64 fetch_time_value;
  if (!base::StringToInt64(fetch_time_string, &fetch_time_value))
    return false;

  if (crx_path)
    *crx_path = FilePath(path_string);

  if (version)
    *version = tmp_version;

  if (fetch_time)
    *fetch_time = base::Time::FromInternalValue(fetch_time_value);

  return true;
}

std::set<std::string> ExtensionPrefs::GetIdleInstallInfoIds() {
  std::set<std::string> result;

  const DictionaryValue* extensions = prefs_->GetDictionary(kExtensionsPref);
  if (!extensions)
    return result;

  for (DictionaryValue::key_iterator iter = extensions->begin_keys();
       iter != extensions->end_keys(); ++iter) {
    const std::string& id(*iter);
    if (!Extension::IdIsValid(id)) {
      NOTREACHED();
      continue;
    }

    const DictionaryValue* extension_prefs = GetExtensionPref(id);
    if (!extension_prefs)
      continue;

    if (extension_prefs->GetDictionary(kIdleInstallInfo, NULL))
      result.insert(id);
  }
  return result;
}

bool ExtensionPrefs::GetWebStoreLogin(std::string* result) {
  if (prefs_->HasPrefPath(kWebStoreLogin)) {
    *result = prefs_->GetString(kWebStoreLogin);
    return true;
  }
  return false;
}

void ExtensionPrefs::SetWebStoreLogin(const std::string& login) {
  prefs_->SetString(kWebStoreLogin, login);
  SavePrefs();
}

int ExtensionPrefs::GetAppLaunchIndex(const std::string& extension_id) {
  int value;
  if (ReadExtensionPrefInteger(extension_id, kPrefAppLaunchIndex, &value))
    return value;

  return -1;
}

void ExtensionPrefs::SetAppLaunchIndex(const std::string& extension_id,
                                       int index) {
  DCHECK_GE(index, 0);
  UpdateExtensionPref(extension_id, kPrefAppLaunchIndex,
                      Value::CreateIntegerValue(index));
}

int ExtensionPrefs::GetNextAppLaunchIndex() {
  const DictionaryValue* extensions = prefs_->GetDictionary(kExtensionsPref);
  if (!extensions)
    return 0;

  int max_value = -1;
  for (DictionaryValue::key_iterator extension_id = extensions->begin_keys();
       extension_id != extensions->end_keys(); ++extension_id) {
    int value = GetAppLaunchIndex(*extension_id);
    if (value > max_value)
      max_value = value;
  }
  return max_value + 1;
}

void ExtensionPrefs::SetAppLauncherOrder(
    const std::vector<std::string>& extension_ids) {
  for (size_t i = 0; i < extension_ids.size(); ++i)
    SetAppLaunchIndex(extension_ids.at(i), i);

  NotificationService::current()->Notify(
      chrome::NOTIFICATION_EXTENSION_LAUNCHER_REORDERED,
      Source<ExtensionPrefs>(this),
      NotificationService::NoDetails());
}

int ExtensionPrefs::GetPageIndex(const std::string& extension_id) {
  int value = -1;
  ReadExtensionPrefInteger(extension_id, kPrefPageIndex, &value);
  return value;
}

void ExtensionPrefs::SetPageIndex(const std::string& extension_id, int index) {
  CHECK_GE(index, 0);
  UpdateExtensionPref(extension_id, kPrefPageIndex,
                      Value::CreateIntegerValue(index));
}

bool ExtensionPrefs::WasAppDraggedByUser(const std::string& extension_id) {
  return ReadExtensionPrefBoolean(extension_id, kPrefUserDraggedApp);
}

void ExtensionPrefs::SetAppDraggedByUser(const std::string& extension_id) {
  UpdateExtensionPref(extension_id, kPrefUserDraggedApp,
                      Value::CreateBooleanValue(true));
}

void ExtensionPrefs::SetUpdateUrlData(const std::string& extension_id,
                                      const std::string& data) {
  UpdateExtensionPref(extension_id, kUpdateUrlData,
                      Value::CreateStringValue(data));
}

std::string ExtensionPrefs::GetUpdateUrlData(const std::string& extension_id) {
  const DictionaryValue* dictionary = GetExtensionPref(extension_id);
  if (!dictionary)
    return std::string();

  std::string data;
  dictionary->GetString(kUpdateUrlData, &data);
  return data;
}

base::Time ExtensionPrefs::GetCurrentTime() const {
  return base::Time::Now();
}

void ExtensionPrefs::OnContentSettingChanged(
    const std::string& extension_id,
    bool incognito) {
  if (incognito) {
    UpdateExtensionPref(
        extension_id, kPrefIncognitoContentSettings,
        content_settings_store_->GetSettingsForExtension(
            extension_id, kExtensionPrefsScopeIncognitoPersistent));
  } else {
    UpdateExtensionPref(
        extension_id, kPrefContentSettings,
        content_settings_store_->GetSettingsForExtension(
            extension_id, kExtensionPrefsScopeRegular));
  }
}

bool ExtensionPrefs::IsFromWebStore(
    const std::string& extension_id) const {
  const DictionaryValue* dictionary = GetExtensionPref(extension_id);
  bool result = false;
  if (dictionary && dictionary->GetBoolean(kPrefFromWebStore, &result))
    return result;
  return false;
}

bool ExtensionPrefs::IsFromBookmark(
    const std::string& extension_id) const {
  const DictionaryValue* dictionary = GetExtensionPref(extension_id);
  bool result = false;
  if (dictionary && dictionary->GetBoolean(kPrefFromBookmark, &result))
    return result;
  return false;
}

base::Time ExtensionPrefs::GetInstallTime(
    const std::string& extension_id) const {
  const DictionaryValue* extension = GetExtensionPref(extension_id);
  if (!extension) {
    NOTREACHED();
    return base::Time();
  }
  std::string install_time_str;
  if (!extension->GetString(kPrefInstallTime, &install_time_str))
    return base::Time();
  int64 install_time_i64 = 0;
  if (!base::StringToInt64(install_time_str, &install_time_i64))
    return base::Time();
  return base::Time::FromInternalValue(install_time_i64);
}

void ExtensionPrefs::GetExtensions(ExtensionIdSet* out) {
  CHECK(out);

  scoped_ptr<ExtensionsInfo> extensions_info(GetInstalledExtensionsInfo());

  for (size_t i = 0; i < extensions_info->size(); ++i) {
    ExtensionInfo* info = extensions_info->at(i).get();
    out->push_back(info->extension_id);
  }
}

void ExtensionPrefs::FixMissingPrefs(const ExtensionIdSet& extension_ids) {
  // Fix old entries that did not get an installation time entry when they
  // were installed or don't have a preferences field.
  for (ExtensionIdSet::const_iterator ext_id = extension_ids.begin();
       ext_id != extension_ids.end(); ++ext_id) {
    if (GetInstallTime(*ext_id) == base::Time()) {
      LOG(INFO) << "Could not parse installation time of extension "
                << *ext_id << ". It was probably installed before setting "
                << kPrefInstallTime << " was introduced. Updating "
                << kPrefInstallTime << " to the current time.";
      const base::Time install_time = GetCurrentTime();
      UpdateExtensionPref(*ext_id, kPrefInstallTime, Value::CreateStringValue(
          base::Int64ToString(install_time.ToInternalValue())));
    }
  }
}

const DictionaryValue* ExtensionPrefs::GetExtensionControlledPrefs(
    const std::string& extension_id,
    bool incognito) const {
  std::string key = extension_id + std::string(".") +
      (incognito ? kPrefIncognitoPreferences : kPrefPreferences);
  DictionaryValue* preferences = NULL;
  // First try the regular lookup.
  const DictionaryValue* source_dict = prefs_->GetDictionary(kExtensionsPref);
  if (!source_dict->GetDictionary(key, &preferences)) {
    // And then create a dictionary if it did not exist before.
    DictionaryPrefUpdate update(prefs_, kExtensionsPref);
    preferences = new DictionaryValue;
    update->Set(key, preferences);
  }
  return preferences;
}

void ExtensionPrefs::InitPrefStore() {
  // When this is called, the PrefService is initialized and provides access
  // to the user preferences stored in a JSON file.
  ExtensionIdSet extension_ids;
  GetExtensions(&extension_ids);
  // Create empty preferences dictionary for each extension (these dictionaries
  // are pruned when persisting the preferences to disk).
  for (ExtensionIdSet::iterator ext_id = extension_ids.begin();
       ext_id != extension_ids.end(); ++ext_id) {
    ScopedExtensionPrefUpdate update(prefs_, *ext_id);
    // This creates an empty dictionary if none is stored.
    update.Get();
  }

  FixMissingPrefs(extension_ids);
  MigratePermissions(extension_ids);

  // Store extension controlled preference values in the
  // |extension_pref_value_map_|, which then informs the subscribers
  // (ExtensionPrefStores) about the winning values.
  for (ExtensionIdSet::iterator ext_id = extension_ids.begin();
       ext_id != extension_ids.end(); ++ext_id) {
    extension_pref_value_map_->RegisterExtension(
        *ext_id,
        GetInstallTime(*ext_id),
        GetExtensionState(*ext_id) == Extension::ENABLED);
    content_settings_store_->RegisterExtension(
        *ext_id,
        GetInstallTime(*ext_id),
        GetExtensionState(*ext_id) == Extension::ENABLED);

    // Set regular extension controlled prefs.
    const DictionaryValue* prefs = GetExtensionControlledPrefs(*ext_id, false);
    for (DictionaryValue::key_iterator i = prefs->begin_keys();
         i != prefs->end_keys(); ++i) {
      Value* value;
      if (!prefs->GetWithoutPathExpansion(*i, &value))
        continue;
      extension_pref_value_map_->SetExtensionPref(
          *ext_id, *i, kExtensionPrefsScopeRegular, value->DeepCopy());
    }

    // Set incognito extension controlled prefs.
    prefs = GetExtensionControlledPrefs(*ext_id, true);
    for (DictionaryValue::key_iterator i = prefs->begin_keys();
         i != prefs->end_keys(); ++i) {
      Value* value;
      if (!prefs->GetWithoutPathExpansion(*i, &value))
        continue;
      extension_pref_value_map_->SetExtensionPref(
          *ext_id, *i, kExtensionPrefsScopeIncognitoPersistent,
          value->DeepCopy());
    }

    const DictionaryValue* extension_prefs = GetExtensionPref(*ext_id);
    DCHECK(extension_prefs);
    ListValue* content_settings = NULL;
    if (extension_prefs->GetList(kPrefContentSettings,
                                 &content_settings)) {
      content_settings_store_->SetExtensionContentSettingsFromList(
          *ext_id, content_settings,
          kExtensionPrefsScopeRegular);
    }
    if (extension_prefs->GetList(kPrefIncognitoContentSettings,
                                 &content_settings)) {
      content_settings_store_->SetExtensionContentSettingsFromList(
          *ext_id, content_settings,
          kExtensionPrefsScopeIncognitoPersistent);
    }
  }

  extension_pref_value_map_->NotifyInitializationCompleted();
}

void ExtensionPrefs::SetExtensionControlledPref(
    const std::string& extension_id,
    const std::string& pref_key,
    ExtensionPrefsScope scope,
    Value* value) {
#ifndef NDEBUG
  const PrefService::Preference* pref =
      pref_service()->FindPreference(pref_key.c_str());
  DCHECK(pref) << "Extension controlled preference key " << pref_key
               << " not registered.";
  DCHECK_EQ(pref->GetType(), value->GetType())
      << "Extension controlled preference " << pref_key << " has wrong type.";
#endif

  if (scope == kExtensionPrefsScopeRegular) {
    // Also store in persisted Preferences file to recover after a
    // browser restart.
    ScopedExtensionControlledPrefUpdate update(prefs_, extension_id,
                                               kPrefPreferences);
    update->SetWithoutPathExpansion(pref_key, value->DeepCopy());
  } else if (scope == kExtensionPrefsScopeIncognitoPersistent) {
    ScopedExtensionControlledPrefUpdate update(prefs_, extension_id,
                                               kPrefIncognitoPreferences);
    update->SetWithoutPathExpansion(pref_key, value->DeepCopy());
  }

  extension_pref_value_map_->SetExtensionPref(
      extension_id, pref_key, scope, value);
}

void ExtensionPrefs::RemoveExtensionControlledPref(
    const std::string& extension_id,
    const std::string& pref_key,
    ExtensionPrefsScope scope) {
  DCHECK(pref_service()->FindPreference(pref_key.c_str()))
      << "Extension controlled preference key " << pref_key
      << " not registered.";

  if (scope == kExtensionPrefsScopeRegular) {
    // Also store in persisted Preferences file to recover after a
    // browser restart.
    ScopedExtensionControlledPrefUpdate update(prefs_, extension_id,
                                               kPrefPreferences);
    update->RemoveWithoutPathExpansion(pref_key, NULL);
  } else if (scope == kExtensionPrefsScopeIncognitoPersistent) {
    ScopedExtensionControlledPrefUpdate update(prefs_, extension_id,
                                               kPrefIncognitoPreferences);
    update->RemoveWithoutPathExpansion(pref_key, NULL);
  }

  extension_pref_value_map_->RemoveExtensionPref(
      extension_id, pref_key, scope);
}

bool ExtensionPrefs::CanExtensionControlPref(const std::string& extension_id,
                                             const std::string& pref_key,
                                             bool incognito) {
  DCHECK(pref_service()->FindPreference(pref_key.c_str()))
      << "Extension controlled preference key " << pref_key
      << " not registered.";

  return extension_pref_value_map_->CanExtensionControlPref(extension_id,
                                                            pref_key,
                                                            incognito);
}

bool ExtensionPrefs::DoesExtensionControlPref(const std::string& extension_id,
                                              const std::string& pref_key,
                                              bool incognito) {
  DCHECK(pref_service()->FindPreference(pref_key.c_str()))
      << "Extension controlled preference key " << pref_key
      << " not registered.";

  return extension_pref_value_map_->DoesExtensionControlPref(extension_id,
                                                             pref_key,
                                                             incognito);
}

bool ExtensionPrefs::HasIncognitoPrefValue(const std::string& pref_key) {
  bool has_incognito_pref_value = false;
  extension_pref_value_map_->GetEffectivePrefValue(pref_key,
                                                   true,
                                                   &has_incognito_pref_value);
  return has_incognito_pref_value;
}

void ExtensionPrefs::ClearIncognitoSessionOnlyContentSettings() {
  ExtensionIdSet extension_ids;
  GetExtensions(&extension_ids);
  for (ExtensionIdSet::iterator ext_id = extension_ids.begin();
       ext_id != extension_ids.end(); ++ext_id) {
    content_settings_store_->ClearContentSettingsForExtension(
        *ext_id,
        kExtensionPrefsScopeIncognitoSessionOnly);
  }
}

// static
void ExtensionPrefs::RegisterUserPrefs(PrefService* prefs) {
  prefs->RegisterDictionaryPref(kExtensionsPref, PrefService::UNSYNCABLE_PREF);
  prefs->RegisterListPref(kExtensionToolbar, PrefService::UNSYNCABLE_PREF);
  prefs->RegisterIntegerPref(prefs::kExtensionToolbarSize,
                             -1,
                             PrefService::UNSYNCABLE_PREF);
  prefs->RegisterDictionaryPref(kExtensionsBlacklistUpdate,
                                PrefService::UNSYNCABLE_PREF);
  prefs->RegisterListPref(prefs::kExtensionInstallAllowList,
                          PrefService::UNSYNCABLE_PREF);
  prefs->RegisterListPref(prefs::kExtensionInstallDenyList,
                          PrefService::UNSYNCABLE_PREF);
  prefs->RegisterListPref(prefs::kExtensionInstallForceList,
                          PrefService::UNSYNCABLE_PREF);
  prefs->RegisterStringPref(kWebStoreLogin,
                            std::string() /* default_value */,
                            PrefService::UNSYNCABLE_PREF);
}