chrome/browser/prefs/pref_service.cc

// Copyright (c) 2010 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/prefs/pref_service.h"

#include <algorithm>
#include <string>

#include "app/l10n_util.h"
#include "base/command_line.h"
#include "base/file_path.h"
#include "base/file_util.h"
#include "base/histogram.h"
#include "base/logging.h"
#include "base/message_loop.h"
#include "base/stl_util-inl.h"
#include "base/string_number_conversions.h"
#include "base/string_util.h"
#include "base/sys_string_conversions.h"
#include "base/utf_string_conversions.h"
#include "build/build_config.h"
#include "chrome/browser/chrome_thread.h"
#include "chrome/browser/profile.h"
#include "chrome/common/notification_service.h"
#include "grit/chromium_strings.h"
#include "grit/generated_resources.h"

namespace {

// A helper function for RegisterLocalized*Pref that creates a Value* based on
// the string value in the locale dll.  Because we control the values in a
// locale dll, this should always return a Value of the appropriate type.
Value* CreateLocaleDefaultValue(Value::ValueType type, int message_id) {
  std::string resource_string = l10n_util::GetStringUTF8(message_id);
  DCHECK(!resource_string.empty());
  switch (type) {
    case Value::TYPE_BOOLEAN: {
      if ("true" == resource_string)
        return Value::CreateBooleanValue(true);
      if ("false" == resource_string)
        return Value::CreateBooleanValue(false);
      break;
    }

    case Value::TYPE_INTEGER: {
      int val;
      base::StringToInt(resource_string, &val);
      return Value::CreateIntegerValue(val);
    }

    case Value::TYPE_REAL: {
      double val;
      base::StringToDouble(resource_string, &val);
      return Value::CreateRealValue(val);
    }

    case Value::TYPE_STRING: {
      return Value::CreateStringValue(resource_string);
    }

    default: {
      NOTREACHED() <<
          "list and dictionary types can not have default locale values";
    }
  }
  NOTREACHED();
  return Value::CreateNullValue();
}

// Forwards a notification after a PostMessage so that we can wait for the
// MessageLoop to run.
void NotifyReadError(PrefService* pref, int message_id) {
  Source<PrefService> source(pref);
  NotificationService::current()->Notify(NotificationType::PROFILE_ERROR,
                                         source, Details<int>(&message_id));
}

}  // namespace

// static
PrefService* PrefService::CreatePrefService(const FilePath& pref_filename,
                                            Profile* profile) {
#if defined(OS_LINUX)
  // We'd like to see what fraction of our users have the preferences
  // stored on a network file system, as we've had no end of troubles
  // with NFS/AFS.
  // TODO(evanm): remove this once we've collected state.
  file_util::FileSystemType fstype;
  if (file_util::GetFileSystemType(pref_filename.DirName(), &fstype)) {
    UMA_HISTOGRAM_ENUMERATION("PrefService.FileSystemType",
                              static_cast<int>(fstype),
                              file_util::FILE_SYSTEM_TYPE_COUNT);
  }
#endif

  return new PrefService(
      PrefValueStore::CreatePrefValueStore(pref_filename, profile, false));
}

// static
PrefService* PrefService::CreateUserPrefService(const FilePath& pref_filename) {
  return new PrefService(
      PrefValueStore::CreatePrefValueStore(pref_filename, NULL, true));
}

PrefService::PrefService(PrefValueStore* pref_value_store)
    : pref_value_store_(pref_value_store) {
  pref_notifier_.reset(new PrefNotifier(this, pref_value_store));
  InitFromStorage();
}

PrefService::~PrefService() {
  DCHECK(CalledOnValidThread());
  STLDeleteContainerPointers(prefs_.begin(), prefs_.end());
  prefs_.clear();
}

void PrefService::InitFromStorage() {
  PrefStore::PrefReadError error = LoadPersistentPrefs();
  if (error == PrefStore::PREF_READ_ERROR_NONE)
    return;

  // Failing to load prefs on startup is a bad thing(TM). See bug 38352 for
  // an example problem that this can cause.
  // Do some diagnosis and try to avoid losing data.
  int message_id = 0;
  if (error <= PrefStore::PREF_READ_ERROR_JSON_TYPE) {
    message_id = IDS_PREFERENCES_CORRUPT_ERROR;
  } else if (error != PrefStore::PREF_READ_ERROR_NO_FILE) {
    message_id = IDS_PREFERENCES_UNREADABLE_ERROR;
  }

  if (message_id) {
    ChromeThread::PostTask(ChromeThread::UI, FROM_HERE,
        NewRunnableFunction(&NotifyReadError, this, message_id));
  }
  UMA_HISTOGRAM_ENUMERATION("PrefService.ReadError", error, 20);
}

bool PrefService::ReloadPersistentPrefs() {
  return (LoadPersistentPrefs() == PrefStore::PREF_READ_ERROR_NONE);
}

PrefStore::PrefReadError PrefService::LoadPersistentPrefs() {
  DCHECK(CalledOnValidThread());

  PrefStore::PrefReadError pref_error = pref_value_store_->ReadPrefs();

  for (PreferenceSet::iterator it = prefs_.begin();
       it != prefs_.end(); ++it) {
    (*it)->pref_value_store_ = pref_value_store_.get();
  }

  return pref_error;
}

bool PrefService::SavePersistentPrefs() {
  DCHECK(CalledOnValidThread());

  return pref_value_store_->WritePrefs();
}

void PrefService::ScheduleSavePersistentPrefs() {
  DCHECK(CalledOnValidThread());

  pref_value_store_->ScheduleWritePrefs();
}

void PrefService::RegisterBooleanPref(const char* path,
                                      bool default_value) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      Value::CreateBooleanValue(default_value));
  RegisterPreference(pref);
}

void PrefService::RegisterIntegerPref(const char* path, int default_value) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      Value::CreateIntegerValue(default_value));
  RegisterPreference(pref);
}

void PrefService::RegisterRealPref(const char* path, double default_value) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      Value::CreateRealValue(default_value));
  RegisterPreference(pref);
}

void PrefService::RegisterStringPref(const char* path,
                                     const std::string& default_value) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      Value::CreateStringValue(default_value));
  RegisterPreference(pref);
}

void PrefService::RegisterFilePathPref(const char* path,
                                       const FilePath& default_value) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      Value::CreateStringValue(default_value.value()));
  RegisterPreference(pref);
}

void PrefService::RegisterListPref(const char* path) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      new ListValue);
  RegisterPreference(pref);
}

void PrefService::RegisterDictionaryPref(const char* path) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      new DictionaryValue());
  RegisterPreference(pref);
}

void PrefService::RegisterLocalizedBooleanPref(const char* path,
                                               int locale_default_message_id) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      CreateLocaleDefaultValue(Value::TYPE_BOOLEAN, locale_default_message_id));
  RegisterPreference(pref);
}

void PrefService::RegisterLocalizedIntegerPref(const char* path,
                                               int locale_default_message_id) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      CreateLocaleDefaultValue(Value::TYPE_INTEGER, locale_default_message_id));
  RegisterPreference(pref);
}

void PrefService::RegisterLocalizedRealPref(const char* path,
                                            int locale_default_message_id) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      CreateLocaleDefaultValue(Value::TYPE_REAL, locale_default_message_id));
  RegisterPreference(pref);
}

void PrefService::RegisterLocalizedStringPref(const char* path,
                                              int locale_default_message_id) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      CreateLocaleDefaultValue(Value::TYPE_STRING, locale_default_message_id));
  RegisterPreference(pref);
}

bool PrefService::GetBoolean(const char* path) const {
  DCHECK(CalledOnValidThread());

  bool result = false;

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return result;
  }
  bool rv = pref->GetValue()->GetAsBoolean(&result);
  DCHECK(rv);
  return result;
}

int PrefService::GetInteger(const char* path) const {
  DCHECK(CalledOnValidThread());

  int result = 0;

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return result;
  }
  bool rv = pref->GetValue()->GetAsInteger(&result);
  DCHECK(rv);
  return result;
}

double PrefService::GetReal(const char* path) const {
  DCHECK(CalledOnValidThread());

  double result = 0.0;

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return result;
  }
  bool rv = pref->GetValue()->GetAsReal(&result);
  DCHECK(rv);
  return result;
}

std::string PrefService::GetString(const char* path) const {
  DCHECK(CalledOnValidThread());

  std::string result;

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return result;
  }
  bool rv = pref->GetValue()->GetAsString(&result);
  DCHECK(rv);
  return result;
}

FilePath PrefService::GetFilePath(const char* path) const {
  DCHECK(CalledOnValidThread());

  FilePath::StringType result;

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return FilePath(result);
  }
  bool rv = pref->GetValue()->GetAsString(&result);
  DCHECK(rv);
#if defined(OS_POSIX)
  // We store filepaths as UTF8, so convert it back to the system type.
  result = base::SysWideToNativeMB(UTF8ToWide(result));
#endif
  return FilePath(result);
}

bool PrefService::HasPrefPath(const char* path) const {
  return pref_value_store_->HasPrefPath(path);
}

const PrefService::Preference* PrefService::FindPreference(
    const char* pref_name) const {
  DCHECK(CalledOnValidThread());
  Preference p(NULL, pref_name, NULL);
  PreferenceSet::const_iterator it = prefs_.find(&p);
  return it == prefs_.end() ? NULL : *it;
}

bool PrefService::IsManagedPreference(const char* pref_name) const {
  const Preference* pref = FindPreference(pref_name);
  if (pref && pref->IsManaged()) {
    return true;
  }
  return false;
}

const DictionaryValue* PrefService::GetDictionary(const char* path) const {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return NULL;
  }
  const Value* value = pref->GetValue();
  if (value->GetType() == Value::TYPE_NULL)
    return NULL;
  return static_cast<const DictionaryValue*>(value);
}

const ListValue* PrefService::GetList(const char* path) const {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return NULL;
  }
  const Value* value = pref->GetValue();
  if (value->GetType() == Value::TYPE_NULL)
    return NULL;
  return static_cast<const ListValue*>(value);
}

void PrefService::AddPrefObserver(const char* path,
                                  NotificationObserver* obs) {
  pref_notifier_->AddPrefObserver(path, obs);
}

void PrefService::RemovePrefObserver(const char* path,
                                     NotificationObserver* obs) {
  pref_notifier_->RemovePrefObserver(path, obs);
}

void PrefService::RegisterPreference(Preference* pref) {
  DCHECK(CalledOnValidThread());

  if (FindPreference(pref->name().c_str())) {
    NOTREACHED() << "Tried to register duplicate pref " << pref->name();
    delete pref;
    return;
  }
  prefs_.insert(pref);
}

void PrefService::ClearPref(const char* path) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to clear an unregistered pref: " << path;
    return;
  }
  Value* value;
  bool has_old_value = pref_value_store_->GetValue(path, &value);
  pref_value_store_->RemoveUserPrefValue(path);

  // TODO(pamg): Removing the user value when there's a higher-priority setting
  // doesn't change the value and shouldn't fire observers.
  if (has_old_value)
    pref_notifier_->FireObservers(path);
}

void PrefService::Set(const char* path, const Value& value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }

  // Allow dictionary and list types to be set to null.
  if (value.GetType() == Value::TYPE_NULL &&
      (pref->type() == Value::TYPE_DICTIONARY ||
       pref->type() == Value::TYPE_LIST)) {
    scoped_ptr<Value> old_value(GetPrefCopy(path));
    if (!old_value->Equals(&value)) {
      pref_value_store_->RemoveUserPrefValue(path);
      pref_notifier_->FireObservers(path);
    }
    return;
  }

  if (pref->type() != value.GetType()) {
    NOTREACHED() << "Wrong type for Set: " << path;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
  pref_value_store_->SetUserPrefValue(path, value.DeepCopy());

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

void PrefService::SetBoolean(const char* path, bool value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }
  if (pref->IsManaged()) {
    NOTREACHED() << "Preference is managed: " << path;
    return;
  }
  if (pref->type() != Value::TYPE_BOOLEAN) {
    NOTREACHED() << "Wrong type for SetBoolean: " << path;
    return;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
  Value* new_value = Value::CreateBooleanValue(value);
  pref_value_store_->SetUserPrefValue(path, new_value);

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

void PrefService::SetInteger(const char* path, int value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }
  if (pref->IsManaged()) {
    NOTREACHED() << "Preference is managed: " << path;
    return;
  }
  if (pref->type() != Value::TYPE_INTEGER) {
    NOTREACHED() << "Wrong type for SetInteger: " << path;
    return;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
  Value* new_value = Value::CreateIntegerValue(value);
  pref_value_store_->SetUserPrefValue(path, new_value);

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

void PrefService::SetReal(const char* path, double value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }
  if (pref->IsManaged()) {
    NOTREACHED() << "Preference is managed: " << path;
    return;
  }
  if (pref->type() != Value::TYPE_REAL) {
    NOTREACHED() << "Wrong type for SetReal: " << path;
    return;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
  Value* new_value = Value::CreateRealValue(value);
  pref_value_store_->SetUserPrefValue(path, new_value);

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

void PrefService::SetString(const char* path, const std::string& value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }
  if (pref->IsManaged()) {
    NOTREACHED() << "Preference is managed: " << path;
    return;
  }
  if (pref->type() != Value::TYPE_STRING) {
    NOTREACHED() << "Wrong type for SetString: " << path;
    return;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
  Value* new_value = Value::CreateStringValue(value);
  pref_value_store_->SetUserPrefValue(path, new_value);

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

void PrefService::SetFilePath(const char* path, const FilePath& value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }
  if (pref->IsManaged()) {
    NOTREACHED() << "Preference is managed: " << path;
    return;
  }
  if (pref->type() != Value::TYPE_STRING) {
    NOTREACHED() << "Wrong type for SetFilePath: " << path;
    return;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
#if defined(OS_POSIX)
  // Value::SetString only knows about UTF8 strings, so convert the path from
  // the system native value to UTF8.
  std::string path_utf8 = WideToUTF8(base::SysNativeMBToWide(value.value()));
  Value* new_value = Value::CreateStringValue(path_utf8);
  pref_value_store_->SetUserPrefValue(path, new_value);
#else
  Value* new_value = Value::CreateStringValue(value.value());
  pref_value_store_->SetUserPrefValue(path, new_value);
#endif

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

void PrefService::SetInt64(const char* path, int64 value) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to write an unregistered pref: " << path;
    return;
  }
  if (pref->IsManaged()) {
    NOTREACHED() << "Preference is managed: " << path;
    return;
  }
  if (pref->type() != Value::TYPE_STRING) {
    NOTREACHED() << "Wrong type for SetInt64: " << path;
    return;
  }

  scoped_ptr<Value> old_value(GetPrefCopy(path));
  Value* new_value = Value::CreateStringValue(base::Int64ToString(value));
  pref_value_store_->SetUserPrefValue(path, new_value);

  pref_notifier_->OnUserPreferenceSet(path, old_value.get());
}

int64 PrefService::GetInt64(const char* path) const {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to read an unregistered pref: " << path;
    return 0;
  }
  std::string result("0");
  bool rv = pref->GetValue()->GetAsString(&result);
  DCHECK(rv);

  int64 val;
  base::StringToInt64(result, &val);
  return val;
}

void PrefService::RegisterInt64Pref(const char* path, int64 default_value) {
  Preference* pref = new Preference(pref_value_store_.get(), path,
      Value::CreateStringValue(base::Int64ToString(default_value)));
  RegisterPreference(pref);
}

DictionaryValue* PrefService::GetMutableDictionary(const char* path) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to get an unregistered pref: " << path;
    return NULL;
  }
  if (pref->type() != Value::TYPE_DICTIONARY) {
    NOTREACHED() << "Wrong type for GetMutableDictionary: " << path;
    return NULL;
  }

  DictionaryValue* dict = NULL;
  Value* tmp_value = NULL;
  if (!pref_value_store_->GetValue(path, &tmp_value) ||
      !tmp_value->IsType(Value::TYPE_DICTIONARY)) {
    dict = new DictionaryValue;
    pref_value_store_->SetUserPrefValue(path, dict);
  } else {
    dict = static_cast<DictionaryValue*>(tmp_value);
  }
  return dict;
}

ListValue* PrefService::GetMutableList(const char* path) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  if (!pref) {
    NOTREACHED() << "Trying to get an unregistered pref: " << path;
    return NULL;
  }
  if (pref->type() != Value::TYPE_LIST) {
    NOTREACHED() << "Wrong type for GetMutableList: " << path;
    return NULL;
  }

  ListValue* list = NULL;
  Value* tmp_value = NULL;
  if (!pref_value_store_->GetValue(path, &tmp_value)) {
    list = new ListValue;
    pref_value_store_->SetUserPrefValue(path, list);
  } else {
    list = static_cast<ListValue*>(tmp_value);
  }
  return list;
}

Value* PrefService::GetPrefCopy(const char* path) {
  DCHECK(CalledOnValidThread());

  const Preference* pref = FindPreference(path);
  DCHECK(pref);
  return pref->GetValue()->DeepCopy();
}

///////////////////////////////////////////////////////////////////////////////
// PrefService::Preference

PrefService::Preference::Preference(PrefValueStore* pref_value_store,
                                    const char* name,
                                    Value* default_value)
      : type_(Value::TYPE_NULL),
        name_(name),
        default_value_(default_value),
        pref_value_store_(pref_value_store) {
  DCHECK(name);

  if (default_value) {
    type_ = default_value->GetType();
    DCHECK(type_ != Value::TYPE_NULL && type_ != Value::TYPE_BINARY) <<
        "invalid preference type: " << type_;
  }

  // We set the default value of lists and dictionaries to be null so it's
  // easier for callers to check for empty list/dict prefs.
  if (Value::TYPE_LIST == type_ || Value::TYPE_DICTIONARY == type_)
    default_value_.reset(Value::CreateNullValue());
}

const Value* PrefService::Preference::GetValue() const {
  DCHECK(NULL != pref_value_store_) <<
      "Must register pref before getting its value";

  Value* temp_value = NULL;
  if (pref_value_store_->GetValue(name_, &temp_value) &&
      temp_value->GetType() == type_) {
    return temp_value;
  }

  // Pref not found, just return the app default.
  return default_value_.get();
}

bool PrefService::Preference::IsDefaultValue() const {
  DCHECK(default_value_.get());
  return default_value_->Equals(GetValue());
}

bool PrefService::Preference::IsManaged() const {
  return pref_value_store_->PrefValueInManagedStore(name_.c_str());
}

bool PrefService::Preference::HasExtensionSetting() const {
  return pref_value_store_->PrefValueInExtensionStore(name_.c_str());
}

bool PrefService::Preference::HasUserSetting() const {
  return pref_value_store_->PrefValueInUserStore(name_.c_str());
}

bool PrefService::Preference::IsExtensionControlled() const {
  return pref_value_store_->PrefValueFromExtensionStore(name_.c_str());
}

bool PrefService::Preference::IsUserControlled() const {
  return pref_value_store_->PrefValueFromUserStore(name_.c_str());
}

bool PrefService::Preference::IsUserModifiable() const {
  return pref_value_store_->PrefValueUserModifiable(name_.c_str());
}