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      1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #include "base/prefs/pref_member.h"
      6 
      7 #include "base/callback.h"
      8 #include "base/callback_helpers.h"
      9 #include "base/location.h"
     10 #include "base/message_loop/message_loop_proxy.h"
     11 #include "base/prefs/pref_service.h"
     12 #include "base/value_conversions.h"
     13 
     14 using base::MessageLoopProxy;
     15 using base::SingleThreadTaskRunner;
     16 
     17 namespace subtle {
     18 
     19 PrefMemberBase::PrefMemberBase()
     20     : prefs_(NULL),
     21       setting_value_(false) {
     22 }
     23 
     24 PrefMemberBase::~PrefMemberBase() {
     25   Destroy();
     26 }
     27 
     28 void PrefMemberBase::Init(const char* pref_name,
     29                           PrefService* prefs,
     30                           const NamedChangeCallback& observer) {
     31   observer_ = observer;
     32   Init(pref_name, prefs);
     33 }
     34 
     35 void PrefMemberBase::Init(const char* pref_name,
     36                           PrefService* prefs) {
     37   DCHECK(pref_name);
     38   DCHECK(prefs);
     39   DCHECK(pref_name_.empty());  // Check that Init is only called once.
     40   prefs_ = prefs;
     41   pref_name_ = pref_name;
     42   // Check that the preference is registered.
     43   DCHECK(prefs_->FindPreference(pref_name_.c_str()))
     44       << pref_name << " not registered.";
     45 
     46   // Add ourselves as a pref observer so we can keep our local value in sync.
     47   prefs_->AddPrefObserver(pref_name, this);
     48 }
     49 
     50 void PrefMemberBase::Destroy() {
     51   if (prefs_ && !pref_name_.empty()) {
     52     prefs_->RemovePrefObserver(pref_name_.c_str(), this);
     53     prefs_ = NULL;
     54   }
     55 }
     56 
     57 void PrefMemberBase::MoveToThread(
     58     const scoped_refptr<SingleThreadTaskRunner>& task_runner) {
     59   VerifyValuePrefName();
     60   // Load the value from preferences if it hasn't been loaded so far.
     61   if (!internal())
     62     UpdateValueFromPref(base::Closure());
     63   internal()->MoveToThread(task_runner);
     64 }
     65 
     66 void PrefMemberBase::OnPreferenceChanged(PrefService* service,
     67                                          const std::string& pref_name) {
     68   VerifyValuePrefName();
     69   UpdateValueFromPref((!setting_value_ && !observer_.is_null()) ?
     70       base::Bind(observer_, pref_name) : base::Closure());
     71 }
     72 
     73 void PrefMemberBase::UpdateValueFromPref(const base::Closure& callback) const {
     74   VerifyValuePrefName();
     75   const PrefService::Preference* pref =
     76       prefs_->FindPreference(pref_name_.c_str());
     77   DCHECK(pref);
     78   if (!internal())
     79     CreateInternal();
     80   internal()->UpdateValue(pref->GetValue()->DeepCopy(),
     81                           pref->IsManaged(),
     82                           pref->IsUserModifiable(),
     83                           callback);
     84 }
     85 
     86 void PrefMemberBase::VerifyPref() const {
     87   VerifyValuePrefName();
     88   if (!internal())
     89     UpdateValueFromPref(base::Closure());
     90 }
     91 
     92 void PrefMemberBase::InvokeUnnamedCallback(const base::Closure& callback,
     93                                            const std::string& pref_name) {
     94   callback.Run();
     95 }
     96 
     97 PrefMemberBase::Internal::Internal()
     98     : thread_loop_(MessageLoopProxy::current()),
     99       is_managed_(false),
    100       is_user_modifiable_(false) {
    101 }
    102 PrefMemberBase::Internal::~Internal() { }
    103 
    104 bool PrefMemberBase::Internal::IsOnCorrectThread() const {
    105   // In unit tests, there may not be a message loop.
    106   return thread_loop_.get() == NULL || thread_loop_->BelongsToCurrentThread();
    107 }
    108 
    109 void PrefMemberBase::Internal::UpdateValue(
    110     base::Value* v,
    111     bool is_managed,
    112     bool is_user_modifiable,
    113     const base::Closure& callback) const {
    114   scoped_ptr<base::Value> value(v);
    115   base::ScopedClosureRunner closure_runner(callback);
    116   if (IsOnCorrectThread()) {
    117     bool rv = UpdateValueInternal(*value);
    118     DCHECK(rv);
    119     is_managed_ = is_managed;
    120     is_user_modifiable_ = is_user_modifiable;
    121   } else {
    122     bool may_run = thread_loop_->PostTask(
    123         FROM_HERE,
    124         base::Bind(&PrefMemberBase::Internal::UpdateValue, this,
    125                    value.release(), is_managed, is_user_modifiable,
    126                    closure_runner.Release()));
    127     DCHECK(may_run);
    128   }
    129 }
    130 
    131 void PrefMemberBase::Internal::MoveToThread(
    132     const scoped_refptr<SingleThreadTaskRunner>& task_runner) {
    133   CheckOnCorrectThread();
    134   thread_loop_ = task_runner;
    135 }
    136 
    137 bool PrefMemberVectorStringUpdate(const base::Value& value,
    138                                   std::vector<std::string>* string_vector) {
    139   if (!value.IsType(base::Value::TYPE_LIST))
    140     return false;
    141   const base::ListValue* list = static_cast<const base::ListValue*>(&value);
    142 
    143   std::vector<std::string> local_vector;
    144   for (base::ListValue::const_iterator it = list->begin();
    145        it != list->end(); ++it) {
    146     std::string string_value;
    147     if (!(*it)->GetAsString(&string_value))
    148       return false;
    149 
    150     local_vector.push_back(string_value);
    151   }
    152 
    153   string_vector->swap(local_vector);
    154   return true;
    155 }
    156 
    157 }  // namespace subtle
    158 
    159 template <>
    160 void PrefMember<bool>::UpdatePref(const bool& value) {
    161   prefs()->SetBoolean(pref_name().c_str(), value);
    162 }
    163 
    164 template <>
    165 bool PrefMember<bool>::Internal::UpdateValueInternal(
    166     const base::Value& value) const {
    167   return value.GetAsBoolean(&value_);
    168 }
    169 
    170 template <>
    171 void PrefMember<int>::UpdatePref(const int& value) {
    172   prefs()->SetInteger(pref_name().c_str(), value);
    173 }
    174 
    175 template <>
    176 bool PrefMember<int>::Internal::UpdateValueInternal(
    177     const base::Value& value) const {
    178   return value.GetAsInteger(&value_);
    179 }
    180 
    181 template <>
    182 void PrefMember<double>::UpdatePref(const double& value) {
    183   prefs()->SetDouble(pref_name().c_str(), value);
    184 }
    185 
    186 template <>
    187 bool PrefMember<double>::Internal::UpdateValueInternal(const base::Value& value)
    188     const {
    189   return value.GetAsDouble(&value_);
    190 }
    191 
    192 template <>
    193 void PrefMember<std::string>::UpdatePref(const std::string& value) {
    194   prefs()->SetString(pref_name().c_str(), value);
    195 }
    196 
    197 template <>
    198 bool PrefMember<std::string>::Internal::UpdateValueInternal(
    199     const base::Value& value)
    200     const {
    201   return value.GetAsString(&value_);
    202 }
    203 
    204 template <>
    205 void PrefMember<base::FilePath>::UpdatePref(const base::FilePath& value) {
    206   prefs()->SetFilePath(pref_name().c_str(), value);
    207 }
    208 
    209 template <>
    210 bool PrefMember<base::FilePath>::Internal::UpdateValueInternal(
    211     const base::Value& value)
    212     const {
    213   return base::GetValueAsFilePath(value, &value_);
    214 }
    215 
    216 template <>
    217 void PrefMember<std::vector<std::string> >::UpdatePref(
    218     const std::vector<std::string>& value) {
    219   base::ListValue list_value;
    220   list_value.AppendStrings(value);
    221   prefs()->Set(pref_name().c_str(), list_value);
    222 }
    223 
    224 template <>
    225 bool PrefMember<std::vector<std::string> >::Internal::UpdateValueInternal(
    226     const base::Value& value) const {
    227   return subtle::PrefMemberVectorStringUpdate(value, &value_);
    228 }
    229