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@1729: #include <map>
Chris@1731: #include <typeinfo>
Chris@1731: #include <iostream>
Chris@1731: #include <climits>
Chris@1729: 
Chris@1729: #include <QMutex>
Chris@1731: #include <QString>
Chris@1729: 
Chris@1738: #include "XmlExportable.h"
Chris@1738: 
Chris@1731: template <typename T>
Chris@1731: struct SvId {
Chris@1735:     
Chris@1731:     int id;
Chris@1729: 
Chris@1735:     enum {
Chris@1735:         // The value NO_ID (-1) is never allocated by WithId
Chris@1735:         NO_ID = -1
Chris@1735:     };
Chris@1735:     
Chris@1735:     SvId() : id(NO_ID) {}
Chris@1735: 
Chris@1735:     SvId(const SvId &) =default;
Chris@1735:     SvId &operator=(const SvId &) =default;
Chris@1735: 
Chris@1735:     bool operator==(const SvId &other) const { return id == other.id; }
Chris@1731:     bool operator<(const SvId &other) const { return id < other.id; }
Chris@1731: 
Chris@1735:     bool isNone() const { return id == NO_ID; }
Chris@1735: 
Chris@1731:     QString toString() const {
Chris@1731:         return QString("%1").arg(id);
Chris@1731:     }
Chris@1731: };
Chris@1731: 
Chris@1731: template <typename T>
Chris@1739: std::ostream &
Chris@1739: operator<<(std::ostream &ostr, const SvId<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@1739:         return (ostr << "#" << id.id);
Chris@1739:     }
Chris@1739: }
Chris@1739: 
Chris@1739: template <typename T>
Chris@1729: class WithId
Chris@1729: {
Chris@1729: public:
Chris@1731:     typedef SvId<T> Id;
Chris@1731:     
Chris@1729:     WithId() :
Chris@1729:         m_id(getNextId()) {
Chris@1729:     }
Chris@1729: 
Chris@1731:     /**
Chris@1731:      * Return an id for this object. The id is a unique identifier for
Chris@1731:      * this object among all objects that implement WithId within this
Chris@1731:      * single run of the application.
Chris@1731:      */
Chris@1729:     Id getId() const {
Chris@1731:         Id id;
Chris@1731:         id.id = m_id;
Chris@1731:         return id;
Chris@1729:     }
Chris@1729: 
Chris@1729: private:
Chris@1731:     int m_id;
Chris@1731: 
Chris@1731:     static int getNextId() {
Chris@1731:         static int nextId = 0;
Chris@1731:         static QMutex mutex;
Chris@1731:         QMutexLocker locker(&mutex);
Chris@1731:         int i = nextId;
Chris@1731:         if (nextId == INT_MAX) {
Chris@1731:             nextId = INT_MIN;
Chris@1735:         } else {
Chris@1735:             ++nextId;
Chris@1735:             if (nextId == 0 || nextId == Id::NO_ID) {
Chris@1735:                 throw std::runtime_error("Internal ID limit exceeded!");
Chris@1735:             }
Chris@1731:         }
Chris@1731:         return i;
Chris@1731:     }
Chris@1729: };
Chris@1729: 
Chris@1731: template <typename Item, typename Id>
Chris@1729: class ById
Chris@1729: {
Chris@1729: public:
Chris@1731:     ~ById() {
Chris@1731:         QMutexLocker locker(&m_mutex);
Chris@1731:         for (const auto &p: m_items) {
Chris@1731:             if (p.second && p.second.use_count() > 0) {
Chris@1734:                 SVCERR << "WARNING: ById map destroyed with use count of "
Chris@1734:                        << p.second.use_count() << " for item with type "
Chris@1734:                        << typeid(*p.second.get()).name()
Chris@1734:                        << " and id " << p.first.id << endl;
Chris@1731:             }
Chris@1731:         }
Chris@1731:     }
Chris@1731:     
Chris@1729:     void add(std::shared_ptr<Item> item) {
Chris@1729:         QMutexLocker locker(&m_mutex);
Chris@1734:         auto id = item->getId();
Chris@1739:         if (id.isNone()) {
Chris@1739:             throw std::logic_error("item id should never be None");
Chris@1739:         }
Chris@1734:         if (m_items.find(id) != m_items.end()) {
Chris@1734:             SVCERR << "WARNING: ById::add: item with id " << id
Chris@1734:                    << " is already recorded, replacing it (item type is "
Chris@1734:                    << typeid(*item.get()).name() << ")" << endl;
Chris@1734:         }
Chris@1734:         m_items[id] = item;
Chris@1729:     }
Chris@1729: 
Chris@1729:     void
Chris@1729:     release(Id id) {
Chris@1729:         QMutexLocker locker(&m_mutex);
Chris@1729:         m_items.erase(id);
Chris@1729:     }
Chris@1729: 
Chris@1729:     std::shared_ptr<Item> get(Id id) const {
Chris@1739:         if (id.isNone()) return {}; // this id is never issued: avoid locking
Chris@1729:         QMutexLocker locker(&m_mutex);
Chris@1729:         const auto &itr = m_items.find(id);
Chris@1729:         if (itr != m_items.end()) {
Chris@1729:             return itr->second;
Chris@1729:         } else {
Chris@1739:             return {};
Chris@1729:         }
Chris@1729:     }
Chris@1729: 
Chris@1729:     template <typename Derived>
Chris@1729:     std::shared_ptr<Derived> getAs(Id id) const {
Chris@1729:         return std::dynamic_pointer_cast<Derived>(get(id));
Chris@1729:     }
Chris@1738: 
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@1738:     int getExportId(Id id) const {
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@1729: private:
Chris@1729:     mutable QMutex m_mutex;
Chris@1729:     std::map<Id, std::shared_ptr<Item>> m_items;
Chris@1729: };
Chris@1729: 
Chris@1731: template <typename Item, typename Id>
Chris@1731: class StaticById
Chris@1729: {
Chris@1729: public:
Chris@1731:     static void add(std::shared_ptr<Item> imagined) {
Chris@1731:         byId().add(imagined);
Chris@1729:     }
Chris@1729: 
Chris@1729:     static void release(Id id) {
Chris@1731:         byId().release(id);
Chris@1729:     }
Chris@1729: 
Chris@1731:     static std::shared_ptr<Item> get(Id id) {
Chris@1731:         return byId().get(id);
Chris@1729:     }
Chris@1729: 
Chris@1729:     template <typename Derived>
Chris@1729:     static
Chris@1729:     std::shared_ptr<Derived> getAs(Id id) {
Chris@1731:         return std::dynamic_pointer_cast<Derived>(get(id));
Chris@1729:     }
Chris@1729: 
Chris@1738:     static int getExportId(Id id) {
Chris@1738:         return byId().getExportId(id);
Chris@1738:     }
Chris@1738:     
Chris@1729: private:
Chris@1731:     static
Chris@1731:     ById<Item, Id> &byId() {
Chris@1731:         static ById<Item, Id> b;
Chris@1731:         return b;
Chris@1731:     }
Chris@1729: };
Chris@1731: 
Chris@1729: #endif
Chris@1729: