| // Copyright 2014 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef LIBBRILLO_BRILLO_DBUS_EXPORTED_PROPERTY_SET_H_ |
| #define LIBBRILLO_BRILLO_DBUS_EXPORTED_PROPERTY_SET_H_ |
| |
| #include <stdint.h> |
| |
| #include <map> |
| #include <memory> |
| #include <string> |
| #include <vector> |
| |
| #include <base/memory/weak_ptr.h> |
| #include <brillo/any.h> |
| #include <brillo/brillo_export.h> |
| #include <brillo/dbus/dbus_signal.h> |
| #include <brillo/errors/error.h> |
| #include <brillo/errors/error_codes.h> |
| #include <brillo/variant_dictionary.h> |
| #include <dbus/exported_object.h> |
| #include <dbus/message.h> |
| |
| namespace brillo { |
| |
| namespace dbus_utils { |
| |
| // This class may be used to implement the org.freedesktop.DBus.Properties |
| // interface. It sends the update signal on property updates: |
| // |
| // org.freedesktop.DBus.Properties.PropertiesChanged ( |
| // STRING interface_name, |
| // DICT<STRING,VARIANT> changed_properties, |
| // ARRAY<STRING> invalidated_properties); |
| // |
| // |
| // and implements the required methods of the interface: |
| // |
| // org.freedesktop.DBus.Properties.Get(in STRING interface_name, |
| // in STRING property_name, |
| // out VARIANT value); |
| // org.freedesktop.DBus.Properties.Set(in STRING interface_name, |
| // in STRING property_name, |
| // in VARIANT value); |
| // org.freedesktop.DBus.Properties.GetAll(in STRING interface_name, |
| // out DICT<STRING,VARIANT> props); |
| // |
| // This class is very similar to the PropertySet class in Chrome, except that |
| // it allows objects to expose properties rather than to consume them. |
| // It is used as part of DBusObject to implement D-Bus object properties on |
| // registered interfaces. See description of DBusObject class for more details. |
| |
| class DBusInterface; |
| class DBusObject; |
| |
| class BRILLO_EXPORT ExportedPropertyBase { |
| public: |
| enum class Access { |
| kReadOnly, |
| kWriteOnly, |
| kReadWrite, |
| }; |
| |
| ExportedPropertyBase() = default; |
| virtual ~ExportedPropertyBase() = default; |
| |
| using OnUpdateCallback = base::Callback<void(const ExportedPropertyBase*)>; |
| |
| // Called by ExportedPropertySet to register a callback. This callback |
| // triggers ExportedPropertySet to send a signal from the properties |
| // interface of the exported object. |
| virtual void SetUpdateCallback(const OnUpdateCallback& cb); |
| |
| // Clears the update callback that was previously set with SetUpdateCallback. |
| virtual void ClearUpdateCallback(); |
| |
| // Returns the contained value as Any. |
| virtual brillo::Any GetValue() const = 0; |
| |
| virtual bool SetValue(brillo::ErrorPtr* error, const brillo::Any& value) = 0; |
| |
| void SetAccessMode(Access access_mode); |
| Access GetAccessMode() const; |
| |
| protected: |
| // Notify the listeners of OnUpdateCallback that the property has changed. |
| void NotifyPropertyChanged(); |
| |
| private: |
| OnUpdateCallback on_update_callback_; |
| // Default to read-only. |
| Access access_mode_{Access::kReadOnly}; |
| }; |
| |
| class BRILLO_EXPORT ExportedPropertySet { |
| public: |
| using PropertyWriter = base::Callback<void(VariantDictionary* dict)>; |
| |
| explicit ExportedPropertySet(::dbus::Bus* bus); |
| ExportedPropertySet(const ExportedPropertySet&) = delete; |
| ExportedPropertySet& operator=(const ExportedPropertySet&) = delete; |
| |
| virtual ~ExportedPropertySet() = default; |
| |
| // Called to notify ExportedPropertySet that the Properties interface of the |
| // D-Bus object has been exported successfully and property notification |
| // signals can be sent out. |
| void OnPropertiesInterfaceExported(DBusInterface* prop_interface); |
| |
| // Return a callback that knows how to write this property set's properties |
| // to a message. This writer retains a weak pointer to this, and must |
| // only be invoked on the same thread as the rest of ExportedPropertySet. |
| PropertyWriter GetPropertyWriter(const std::string& interface_name); |
| |
| void RegisterProperty(const std::string& interface_name, |
| const std::string& property_name, |
| ExportedPropertyBase* exported_property); |
| |
| // Unregisters a property from this exported property set. |
| void UnregisterProperty(const std::string& interface_name, |
| const std::string& property_name); |
| |
| // D-Bus methods for org.freedesktop.DBus.Properties interface. |
| VariantDictionary HandleGetAll(const std::string& interface_name); |
| bool HandleGet(brillo::ErrorPtr* error, |
| const std::string& interface_name, |
| const std::string& property_name, |
| brillo::Any* result); |
| // While Properties.Set has a handler to complete the interface, we don't |
| // support writable properties. This is almost a feature, since bindings for |
| // many languages don't support errors coming back from invalid writes. |
| // Instead, use setters in exposed interfaces. |
| bool HandleSet(brillo::ErrorPtr* error, |
| const std::string& interface_name, |
| const std::string& property_name, |
| const brillo::Any& value); |
| // Returns a string-to-variant map of all the properties for the given |
| // interface and their values. |
| VariantDictionary GetInterfaceProperties( |
| const std::string& interface_name) const; |
| |
| private: |
| // Used to write the dictionary of string->variant to a message. |
| // This dictionary represents the property name/value pairs for the |
| // given interface. |
| BRILLO_PRIVATE void WritePropertiesToDict(const std::string& interface_name, |
| VariantDictionary* dict); |
| BRILLO_PRIVATE void HandlePropertyUpdated( |
| const std::string& interface_name, |
| const std::string& property_name, |
| const ExportedPropertyBase* exported_property); |
| |
| ::dbus::Bus* bus_; // weak; owned by outer DBusObject containing this object. |
| // This is a map from interface name -> property name -> pointer to property. |
| std::map<std::string, std::map<std::string, ExportedPropertyBase*>> |
| properties_; |
| |
| // D-Bus callbacks may last longer the property set exporting those methods. |
| base::WeakPtrFactory<ExportedPropertySet> weak_ptr_factory_; |
| |
| using SignalPropertiesChanged = |
| DBusSignal<std::string, VariantDictionary, std::vector<std::string>>; |
| |
| std::weak_ptr<SignalPropertiesChanged> signal_properties_changed_; |
| |
| friend class DBusObject; |
| friend class ExportedPropertySetTest; |
| }; |
| |
| template <typename T> |
| class ExportedProperty : public ExportedPropertyBase { |
| public: |
| ExportedProperty() = default; |
| ExportedProperty(const ExportedProperty&) = delete; |
| ExportedProperty& operator=(const ExportedProperty&) = delete; |
| |
| ~ExportedProperty() override = default; |
| |
| // Retrieves the current value. |
| const T& value() const { return value_; } |
| |
| // Set the value exposed to remote applications. This triggers notifications |
| // of changes over the Properties interface. |
| void SetValue(const T& new_value) { |
| if (value_ != new_value) { |
| value_ = new_value; |
| this->NotifyPropertyChanged(); |
| } |
| } |
| |
| // Set the validator for value checking when setting the property by remote |
| // application. |
| void SetValidator( |
| const base::Callback<bool(brillo::ErrorPtr*, const T&)>& validator) { |
| validator_ = validator; |
| } |
| |
| // Implementation provided by specialization. |
| brillo::Any GetValue() const override { return value_; } |
| |
| bool SetValue(brillo::ErrorPtr* error, const brillo::Any& value) override { |
| if (GetAccessMode() == ExportedPropertyBase::Access::kReadOnly) { |
| brillo::Error::AddTo(error, FROM_HERE, errors::dbus::kDomain, |
| DBUS_ERROR_PROPERTY_READ_ONLY, |
| "Property is read-only."); |
| return false; |
| } |
| if (!value.IsTypeCompatible<T>()) { |
| brillo::Error::AddTo(error, FROM_HERE, errors::dbus::kDomain, |
| DBUS_ERROR_INVALID_ARGS, |
| "Argument type mismatched."); |
| return false; |
| } |
| if (value_ == value.Get<T>()) { |
| // No change to the property value, nothing to be done. |
| return true; |
| } |
| if (!validator_.is_null() && !validator_.Run(error, value.Get<T>())) { |
| return false; |
| } |
| SetValue(value.Get<T>()); |
| return true; |
| } |
| |
| private: |
| T value_{}; |
| base::Callback<bool(brillo::ErrorPtr*, const T&)> validator_; |
| }; |
| |
| } // namespace dbus_utils |
| |
| } // namespace brillo |
| |
| #endif // LIBBRILLO_BRILLO_DBUS_EXPORTED_PROPERTY_SET_H_ |