Property/include/OgreProperty.h

/*
-----------------------------------------------------------------------------
This source file is part of OGRE
(Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2014 Torus Knot Software Ltd

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The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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*/
#ifndef __OGRE_PROPERTY_H__
#define __OGRE_PROPERTY_H__

#include "OgrePropertyPrerequisites.h"
#include "OgreAny.h"
#include "OgreString.h"
#include "OgreException.h"
#include "OgreQuaternion.h"
#include "OgreMatrix4.h"

#include <functional>

/** \addtogroup Optional
*  @{
*/
/** \defgroup Property Property
* Associate values of arbitrary type with names
*  @{
*/

/** @file
    OGRE's property system allows you to associate values of arbitrary type with
    names, and have those values exposed via a self-describing interface. Unlike
    Ogre::StringInterface, the values are passed as their native types without
    needing conversion to or from strings; they are simply wrapped in an Ogre::Any
    and casts are performed to access them.
    @par
    Property values are actually not stored in this system; instead the property
    definitions reference getter & setter methods which provide the 'backing' for
    the property. This means you can directly expose features of your classes as properties
    without any duplication.
    @par
    There are two aspects to exposing a property on your class. One is exposing
    the definition of the property (PropertyDef), which should be shared between
    all instances and probably stored in a static PropertyDefMap somewhere. The second
    is the instance 'wiring' which ensures that a call to set a property calls
    a method on this particular instance of the class; this is formed by a number of
    Property instances, contained in a PropertySet. Each Property has an explicit
    binding to getter and setter instance methods.
    @par
    So, here's an example of setting up properties on an instance:

    @code
    // Make sure the property definition is created
    // propertyDefs is a variable of type PropertyDefMap, shared between instances
    PropertyDefMap::iterator defi = propertyDefs.find("name");
    if (defi == propertyDefs.end())
    {
        defi = propertyDefs.insert(PropertyDefMap::value_type("name",
            PropertyDef("name",
                "The name of the object.", PROP_STRING))).first;
    }
    // This has established the property definition, and its description.
    // Now, we need to 'wire' a property instance for this object instance
    // We assume the class is called 'Foo' and the instance is pointed to by a variable called 'inst'
    // 'props' is a PropertySet, specific to the instance
    props.addProperty(
        OGRE_NEW Property<String>(&(defi->second),
            std::bind(&Foo::getName, inst),
            std::bind(&Foo::setName, inst, _1)));

    @endcode

*/

/** @} */
/** @} */
namespace Ogre
{
    using std::function;

    /** \addtogroup Optional
    *  @{
    */
    /** \addtogroup Property
    *  @{
    */

    /// The type of a property
    enum PropertyType
    {
        PROP_SHORT = 0,
        PROP_UNSIGNED_SHORT = 1,
        PROP_INT = 2,
        PROP_UNSIGNED_INT = 3,
        PROP_LONG = 4,
        PROP_UNSIGNED_LONG = 5,
        PROP_REAL = 6,
        PROP_STRING = 7,
        PROP_VECTOR2 = 8,
        PROP_VECTOR3 = 9,
        PROP_VECTOR4 = 10,
        PROP_COLOUR = 11,
        PROP_BOOL = 12,
        PROP_QUATERNION = 13,
        PROP_MATRIX3 = 14,
        PROP_MATRIX4 = 15,

        PROP_UNKNOWN = 999
    };

    typedef GeneralAllocatedObject PropertyAlloc;

    /** Definition of a property of an object.
    @remarks
    This definition is shared between all instances of an object and therefore
    has no value. Property contains values.
    */
    class _OgrePropertyExport PropertyDef : public PropertyAlloc
    {
    public:

        /** Construct a property.
        @param name The name of the property
        @param desc A (potentially) long description of the property
        @param pType The type of the property
        */
        PropertyDef(const String& name, const String& desc, PropertyType pType)
            : mName(name), mDesc(desc), mType(pType) {}

        /// Get the name of the property
        const String& getName() const { return mName; }

        /// Get the description of the property
        const String& getDescription() const { return mDesc; }

        /// Get the type of the property
        PropertyType getType() const { return mType; }

        /// Get a string name of a property type
        static const String& getTypeName(PropertyType theType);

        static PropertyType getTypeForValue(const short& val) { return PROP_SHORT; }
        static PropertyType getTypeForValue(const unsigned short& val) { return PROP_UNSIGNED_SHORT; }
        static PropertyType getTypeForValue(const int& val) { return PROP_INT; }
        static PropertyType getTypeForValue(const unsigned int& val) { return PROP_UNSIGNED_INT; }
        static PropertyType getTypeForValue(const long& val) { return PROP_LONG; }
        static PropertyType getTypeForValue(const unsigned long& val) { return PROP_UNSIGNED_LONG; }
        static PropertyType getTypeForValue(const Real& val) { return PROP_REAL; }
        static PropertyType getTypeForValue(const String& val) { return PROP_STRING; }
        static PropertyType getTypeForValue(const Vector2& val) { return PROP_VECTOR2; }
        static PropertyType getTypeForValue(const Vector3& val) { return PROP_VECTOR3; }
        static PropertyType getTypeForValue(const Vector4& val) { return PROP_VECTOR4; }
        static PropertyType getTypeForValue(const ColourValue& val) { return PROP_COLOUR; }
        static PropertyType getTypeForValue(const bool& val) { return PROP_BOOL; }
        static PropertyType getTypeForValue(const Quaternion& val) { return PROP_QUATERNION; }
        static PropertyType getTypeForValue(const Matrix3& val) { return PROP_MATRIX3; }
        static PropertyType getTypeForValue(const Matrix4& val) { return PROP_MATRIX4; }

    protected:
        // no default construction
        PropertyDef() {}

        String mName;
        String mDesc;
        PropertyType mType;

    };

    /// Map from property name to shared definition
    typedef std::map<String, PropertyDef> PropertyDefMap;

    /** Base interface for an instance of a property.
    */
    class _OgrePropertyExport PropertyBase : public PropertyAlloc
    {
    public:
        /// Constructor
        PropertyBase(PropertyDef* def) : mDef(def) {}
        virtual ~PropertyBase() {}

        /// Get the name of the property
        const String& getName() const { return mDef->getName(); }

        /// Get the description of the property
        const String& getDescription() const { return mDef->getDescription(); }

        /// Get the type of the property
        PropertyType getType() const { return mDef->getType(); }

        /// Return the current value as an Any
        virtual Ogre::Any getValue() const = 0;

    protected:
        // disallow default construction
        PropertyBase() {}
        PropertyDef* mDef;

    };

    /** Property instance with passthrough calls to a given object. */
    template <typename T>
    class Property : public PropertyBase
    {
    public:
        typedef T value_type;
        typedef function< T (void) > getter_func;
        typedef function< void (T) > setter_func;

        /** Construct a property which is able to directly call a given
        getter and setter on a specific object instance, via functors.
        */
        Property(PropertyDef* def, getter_func getter, setter_func setter)
            : PropertyBase(def)
            , mGetter(getter)
            , mSetter(setter)
        {
        }

        /** Set the property value.
        */
        virtual void set(T val)
        {
            mSetter(val);
        }

        virtual T get() const
        {
            return mGetter();
        }

        Ogre::Any getValue() const
        {
            return Ogre::Any(get());
        }

    protected:
        // disallow default construction
        Property() {}
        ~Property() {}

        getter_func mGetter;
        setter_func mSetter;
    };

    /** A simple structure designed just as a holder of property values between
    the instances of objects they might target. There is just enough information
    here to be able to interpret the results accurately but no more.
    */
    struct PropertyValue
    {
        PropertyType propType;
        Ogre::Any val;
    };
    /// Defines a transferable map of properties using wrapped value types (Ogre::Any)
    typedef std::map<String, PropertyValue> PropertyValueMap;


    /** Defines a complete set of properties for a single object instance.
    */
    class _OgrePropertyExport PropertySet : public PropertyAlloc
    {
    public:
        PropertySet();
        ~PropertySet();

        /** Adds a property to this set.
        @remarks
        The PropertySet is responsible for deleting this object.
        */
        void addProperty(PropertyBase* prop);

        /** Gets the property object for a given property name.
        @remarks
        Note that this property will need to be cast to a templated property
        compatible with the type you will be setting. You might find the
        overloaded set and get<type> methods quicker if
        you already know the type.
        */
        PropertyBase* getProperty(const String& name) const;

        /** Reports whether this property set contains a named property. */
        bool hasProperty(const String& name) const;

        /** Removes the named property from the property set. */
        void removeProperty(const String& name);

        typedef std::map<String, PropertyBase*> PropertyMap;

        /** Gets an independently usable collection of property values from the
        current state.
        */
        PropertyValueMap getValueMap() const;

        /** Sets the current state from a given value map.
        */
        void setValueMap(const PropertyValueMap& values);

        /** Get a named property value.
        */
        template<typename T>
        void getValue(const String& name, T& value) const
        {
            getPropertyImpl(name, value, PropertyDef::getTypeForValue(value));
        }

        /** Set a named property value (via pointer to avoid copy).
        */
        template<typename T>
        void setValue(const String& name, const T* value)
        {
            setPropertyImpl(name, *value, PropertyDef::getTypeForValue(*value));
        }
        /** Set a named property value.
        */
        template<typename T>
        void setValue(const String& name, T value)
        {
            setPropertyImpl(name, value, PropertyDef::getTypeForValue(value));
        }
        /** Special-case char*, convert to String automatically.
        */
        void setValue(const String& name, const char* pChar)
        {
            String v(pChar);
            setPropertyImpl(name, v, PROP_STRING);
        }


    protected:
        PropertyMap mPropertyMap;

        /// Set a named property value, internal implementation (type match required)
        template <typename T>
        void setPropertyImpl(const String& name, const T& val, PropertyType typeCheck)
        {
            PropertyBase* baseProp = getProperty(name);
            if (baseProp->getType() != typeCheck)
            {
                StringStream msg;
                msg << "Property error: type passed in: '" << PropertyDef::getTypeName(typeCheck)
                    << "', type of property: '" << PropertyDef::getTypeName(baseProp->getType()) << "'";
                OGRE_EXCEPT(Exception::ERR_INVALIDPARAMS, msg.str(), "PropertySet::setPropertyImpl");
            }
            static_cast<Property<T>*>(baseProp)->set(val);
        }

        /// Get a named property value, internal implementation (type match required)
        template <typename T>
        void getPropertyImpl(const String& name, T& refVal, PropertyType typeCheck) const
        {
            PropertyBase* baseProp = getProperty(name);
            if (baseProp->getType() != typeCheck)
            {
                StringStream msg;
                msg << "Property error: type requested: '" << PropertyDef::getTypeName(typeCheck)
                    << "', type of property: '" << PropertyDef::getTypeName(baseProp->getType()) << "'";
                OGRE_EXCEPT(Exception::ERR_INVALIDPARAMS, msg.str(), "PropertySet::getPropertyImpl");
            }
            refVal = static_cast<Property<T>*>(baseProp)->get();
        }

    };

    /** @} */
    /** @} */

}

#endif