Chris@1729: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@1729: 
Chris@1729: /*
Chris@1729:     Sonic Visualiser
Chris@1729:     An audio file viewer and annotation editor.
Chris@1729:     Centre for Digital Music, Queen Mary, University of London.
Chris@1729:     
Chris@1729:     This program is free software; you can redistribute it and/or
Chris@1729:     modify it under the terms of the GNU General Public License as
Chris@1729:     published by the Free Software Foundation; either version 2 of the
Chris@1729:     License, or (at your option) any later version.  See the file
Chris@1729:     COPYING included with this distribution for more information.
Chris@1729: */
Chris@1729: 
Chris@1729: #ifndef SV_BY_ID_H
Chris@1729: #define SV_BY_ID_H
Chris@1729: 
Chris@1734: #include "Debug.h"
Chris@1734: 
Chris@1729: #include <memory>
Chris@1731: #include <iostream>
Chris@1731: #include <climits>
Chris@1742: #include <stdexcept>
Chris@1729: 
Chris@1729: #include <QMutex>
Chris@1731: #include <QString>
Chris@1729: 
Chris@1738: #include "XmlExportable.h"
Chris@1738: 
Chris@1744: //!!! todo: docs
Chris@1744: 
Chris@1750: //!!! further possibilities:
Chris@1750: //
Chris@1750: //    - id can only be queried when an object is added to ById (maybe
Chris@1750: //      add() returns the id, and there is a ById::idOf, but the
Chris@1750: //      object has no public getId())
Chris@1750: //
Chris@1750: //    - get() returns a pointer wrapper that cannot be shared/copied
Chris@1750: //      again by the caller (except by the usual C++ trickery)
Chris@1750: //
Chris@1750: // also to do: review how often we are calling getAs<...> when we
Chris@1750: // could just be using get
Chris@1750: 
Chris@1742: struct IdAlloc {
Chris@1742: 
Chris@1742:     // The value NO_ID (-1) is never allocated
Chris@1742:     static const int NO_ID = -1;
Chris@1742:     
Chris@1742:     static int getNextId();
Chris@1742: };
Chris@1742: 
Chris@1731: template <typename T>
Chris@1742: struct TypedId {
Chris@1735:     
Chris@1742:     int untyped;
Chris@1742:     
Chris@1742:     TypedId() : untyped(IdAlloc::NO_ID) {}
Chris@1729: 
Chris@1742:     TypedId(const TypedId &) =default;
Chris@1742:     TypedId &operator=(const TypedId &) =default;
Chris@1735: 
Chris@1742:     bool operator==(const TypedId &other) const {
Chris@1742:         return untyped == other.untyped;
Chris@1742:     }
Chris@1742:     bool operator!=(const TypedId &other) const {
Chris@1742:         return untyped != other.untyped;
Chris@1742:     }
Chris@1742:     bool operator<(const TypedId &other) const {
Chris@1742:         return untyped < other.untyped;
Chris@1742:     }
Chris@1742:     bool isNone() const {
Chris@1742:         return untyped == IdAlloc::NO_ID;
Chris@1731:     }
Chris@1731: };
Chris@1731: 
Chris@1731: template <typename T>
Chris@1739: std::ostream &
Chris@1742: operator<<(std::ostream &ostr, const TypedId<T> &id)
Chris@1739: {
Chris@1739:     // For diagnostic purposes only. Do not use these IDs for
Chris@1739:     // serialisation - see XmlExportable instead.
Chris@1739:     if (id.isNone()) {
Chris@1739:         return (ostr << "<none>");
Chris@1739:     } else {
Chris@1742:         return (ostr << "#" << id.untyped);
Chris@1739:     }
Chris@1739: }
Chris@1739: 
Chris@1729: class WithId
Chris@1729: {
Chris@1729: public:
Chris@1729:     WithId() :
Chris@1742:         m_id(IdAlloc::getNextId()) {
Chris@1742:     }
Chris@1742:     virtual ~WithId() {
Chris@1729:     }
Chris@1729: 
Chris@1752: protected:
Chris@1752:     friend class AnyById;
Chris@1752:     
Chris@1731:     /**
Chris@1742:      * Return an id for this object. The id is a unique number for
Chris@1731:      * this object among all objects that implement WithId within this
Chris@1731:      * single run of the application.
Chris@1731:      */
Chris@1742:     int getUntypedId() const {
Chris@1742:         return m_id;
Chris@1742:     }
Chris@1742: 
Chris@1742: private:
Chris@1742:     int m_id;
Chris@1742: };
Chris@1742: 
Chris@1742: template <typename T>
Chris@1742: class WithTypedId : virtual public WithId
Chris@1742: {
Chris@1742: public:
Chris@1742:     typedef TypedId<T> Id;
Chris@1742:     
Chris@1742:     WithTypedId() : WithId() { }
Chris@1742: 
Chris@1752: protected:
Chris@1752:     template <typename Item, typename Id>
Chris@1752:     friend class TypedById;
Chris@1752:     
Chris@1742:     /**
Chris@1742:      * Return an id for this object. The id is a unique value for this
Chris@1742:      * object among all objects that implement WithTypedId within this
Chris@1742:      * single run of the application.
Chris@1742:      */
Chris@1729:     Id getId() const {
Chris@1731:         Id id;
Chris@1742:         id.untyped = getUntypedId();
Chris@1731:         return id;
Chris@1729:     }
Chris@1742: };
Chris@1742: 
Chris@1742: class AnyById
Chris@1742: {
Chris@1742: public:
Chris@1752:     static int add(std::shared_ptr<WithId>);
Chris@1742:     static void release(int);
Chris@1746:     static std::shared_ptr<WithId> get(int); 
Chris@1742: 
Chris@1742:     template <typename Derived>
Chris@1746:     static bool isa(int id) {
Chris@1746:         std::shared_ptr<WithId> p = get(id);
Chris@1746:         return bool(std::dynamic_pointer_cast<Derived>(p));
Chris@1746:     }
Chris@1746:    
Chris@1746:     template <typename Derived>
Chris@1742:     static std::shared_ptr<Derived> getAs(int id) {
Chris@1742:         std::shared_ptr<WithId> p = get(id);
Chris@1742:         return std::dynamic_pointer_cast<Derived>(p);
Chris@1742:     }
Chris@1729: 
Chris@1729: private:
Chris@1742:     class Impl;
Chris@1742:     static Impl &impl();
Chris@1729: };
Chris@1729: 
Chris@1731: template <typename Item, typename Id>
Chris@1742: class TypedById
Chris@1729: {
Chris@1729: public:
Chris@1750:     static Id add(std::shared_ptr<Item> item) {
Chris@1752:         Id id;
Chris@1752:         id.untyped = AnyById::add(item);
Chris@1750:         return id;
Chris@1729:     }
Chris@1729: 
Chris@1742:     static void release(Id id) {
Chris@1742:         AnyById::release(id.untyped);
Chris@1729:     }
Chris@1742:     static void release(std::shared_ptr<Item> item) {
Chris@1742:         release(item->getId());
Chris@1729:     }
Chris@1729: 
Chris@1729:     template <typename Derived>
Chris@1746:     static bool isa(Id id) {
Chris@1746:         return AnyById::isa<Derived>(id.untyped);
Chris@1746:     }
Chris@1746: 
Chris@1746:     template <typename Derived>
Chris@1742:     static std::shared_ptr<Derived> getAs(Id id) {
Chris@1742:         return AnyById::getAs<Derived>(id.untyped);
Chris@1742:     }
Chris@1742: 
Chris@1742:     static std::shared_ptr<Item> get(Id id) {
Chris@1742:         return getAs<Item>(id);
Chris@1729:     }
Chris@1752:     
Chris@1738:     /**
Chris@1738:      * If the Item type is an XmlExportable, return the export ID of
Chris@1739:      * the given item ID. A call to this function will fail to compile
Chris@1739:      * if the Item is not an XmlExportable.
Chris@1739:      *
Chris@1739:      * The export ID is a simple int, and is only allocated when first
Chris@1739:      * requested, so objects that are never exported don't get one.
Chris@1738:      */
Chris@1742:     static int getExportId(Id id) {
Chris@1738:         auto exportable = getAs<XmlExportable>(id);
Chris@1738:         if (exportable) {
Chris@1738:             return exportable->getExportId();
Chris@1738:         } else {
Chris@1738:             return XmlExportable::NO_ID;
Chris@1738:         }
Chris@1738:     }
Chris@1729: };
Chris@1731: 
Chris@1729: #endif
Chris@1729: