annotate base/ById.cpp @ 1742:52705a328b34 by-id

Rejig ById so as to put everything in a single pool, so that at the core you can go from numeric id (untyped) to anything the object can be dynamic_cast to. Useful for building other abstractions like PlayParameter-type registrations that don't know about e.g. Models. Probably some more tweaking needed. Also add tests

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "ById.h"

#include <unordered_map>
#include <typeinfo>

int IdAlloc::getNextId()
{
    static int nextId = 0;
    static QMutex mutex;
    QMutexLocker locker(&mutex);
    int i = nextId;
    if (nextId == INT_MAX) {
        nextId = INT_MIN;
    } else {
        ++nextId;
        if (nextId == 0 || nextId == NO_ID) {
            throw std::runtime_error("Internal ID limit exceeded!");
        }
    }
    return i;
}

class AnyById::Impl
{
public:    
    ~Impl() {
        QMutexLocker locker(&m_mutex);
        bool empty = true;
        for (const auto &p: m_items) {
            if (p.second && p.second.use_count() > 0) {
                empty = false;
                break;
            }
        }
        if (!empty) {
            SVCERR << "WARNING: ById map is not empty at close; some items have not been released" << endl;
            SVCERR << "         Unreleased items are:" << endl;
            for (const auto &p: m_items) {
                if (p.second && p.second.use_count() > 0) {
                    SVCERR << "         - id #" << p.first
                           << ": type " << typeid(*p.second.get()).name()
                           << ", use count " << p.second.use_count() << endl;
                }
            }
        }
    }
        
    void add(int id, std::shared_ptr<WithId> item) {
        QMutexLocker locker(&m_mutex);
        if (m_items.find(id) != m_items.end()) {
            SVCERR << "ById::add: item with id " << id
                   << " is already recorded (existing item type is "
                   << typeid(*m_items.find(id)->second.get()).name()
                   << ", proposed is "
                   << typeid(*item.get()).name() << ")" << endl;
            throw std::logic_error("item id is already recorded in add");
        }
        m_items[id] = item;
    }

    void release(int id) {
        QMutexLocker locker(&m_mutex);
        if (m_items.find(id) == m_items.end()) {
            SVCERR << "ById::release: unknown item id " << id << endl;
            throw std::logic_error("unknown item id in release");
        }
        m_items.erase(id);
    }
    
    std::shared_ptr<WithId> get(int id) const {
        QMutexLocker locker(&m_mutex);
        const auto &itr = m_items.find(id);
        if (itr != m_items.end()) {
            return itr->second;
        } else {
            return {};
        }
    }

private:
    mutable QMutex m_mutex;
    std::unordered_map<int, std::shared_ptr<WithId>> m_items;
};

void
AnyById::add(int id, std::shared_ptr<WithId> item)
{
    impl().add(id, item);
}

void
AnyById::release(int id)
{
    impl().release(id);
}

std::shared_ptr<WithId>
AnyById::get(int id)
{
    return impl().get(id);
}

AnyById::Impl &
AnyById::impl()
{
    static Impl impl;
    return impl;
}