MaskDict.cc

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/*
 * Developed for the LSST Data Management System.
 * This product includes software developed by the LSST Project
 * (https://www.lsst.org).
 * See the COPYRIGHT file at the top-level directory of this distribution
 * for details of code ownership.
 *
 * 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 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <mutex>
#include <set>

#include "boost/functional/hash.hpp"
#include "lsst/afw/image/detail/MaskDict.h"

namespace lsst { namespace afw { namespace image { namespace detail {

// A thread-safe singleton that manages MaskDict's global state.
class MaskDict::GlobalState final {
public:

    static GlobalState & get() {
        static GlobalState instance;
        return instance;
    }

    std::shared_ptr<MaskDict> copyOrGetDefault(MaskPlaneDict const & mpd) {
        std::lock_guard<std::recursive_mutex> lock(_mutex);
        if (!mpd.empty()) {
            std::shared_ptr<MaskDict> dict(new MaskDict(mpd));
            _allMaskDicts.insert(dict);
            return dict;
        }
        return _defaultMaskDict;
    }

    std::shared_ptr<MaskDict> copy(MaskDict const & dict) {
        std::lock_guard<std::recursive_mutex> lock(_mutex);
        std::shared_ptr<MaskDict> result(new MaskDict(dict));
        _allMaskDicts.insert(result);
        return result;
    }

    std::shared_ptr<MaskDict> getDefault() const noexcept {
        return _defaultMaskDict;
    }

    void setDefault(std::shared_ptr<MaskDict> dict) {
        _defaultMaskDict = std::move(dict);
    }

    std::shared_ptr<MaskDict> detachDefault() {
        std::lock_guard<std::recursive_mutex> lock(_mutex);
        _defaultMaskDict = copy(*_defaultMaskDict);
        return _defaultMaskDict;
    }

    template <typename Functor>
    void forEachMaskDict(Functor functor) {
        std::lock_guard<std::recursive_mutex> lock(_mutex);
        _prune();  // guarantees dereference below is safe
        for (auto const & ptr : _allMaskDicts) {
            functor(*ptr.lock());
        }
    }

private:

    GlobalState() : _defaultMaskDict(new MaskDict()) {
        _allMaskDicts.insert(_defaultMaskDict);
        _defaultMaskDict->_addInitialMaskPlanes();
    }

    GlobalState(GlobalState const &) = delete;
    GlobalState(GlobalState &&) = delete;

    GlobalState & operator=(GlobalState const &) = delete;
    GlobalState & operator=(GlobalState &&) = delete;

    ~GlobalState() = default;

    // Prune expired weak_ptrs from _allMaskDicts.  Not thread safe; should
    // only be called by routines that have already locked the mutex.
    void _prune() {
        for (auto iter = _allMaskDicts.begin(); iter != _allMaskDicts.end(); ) {
            if (iter->expired()) {
                iter = _allMaskDicts.erase(iter);
            } else {
                ++iter;
            }
        }
    }

    std::recursive_mutex _mutex;  // guards _allMaskDicts and synchronizes updates to it and _defaultMaskDict
    std::set<std::weak_ptr<MaskDict>, std::owner_less<std::weak_ptr<MaskDict>>> _allMaskDicts;
    std::shared_ptr<MaskDict> _defaultMaskDict;
};

std::shared_ptr<MaskDict> MaskDict::copyOrGetDefault(MaskPlaneDict const& mpd) {
    return GlobalState::get().copyOrGetDefault(mpd);
}

std::shared_ptr<MaskDict> MaskDict::getDefault() {
    return GlobalState::get().getDefault();
}

void MaskDict::setDefault(std::shared_ptr<MaskDict> dict) {
    GlobalState::get().setDefault(std::move(dict));
}

std::shared_ptr<MaskDict> MaskDict::detachDefault() {
    return GlobalState::get().detachDefault();
}

void MaskDict::addAllMasksPlane(std::string const & name, int bitId) {
    GlobalState::get().forEachMaskDict(
        [&name, bitId](MaskDict & dict) {
            auto const found = std::find_if(
                dict.begin(), dict.end(),
                [bitId](auto const & item) { return item.second == bitId; }
            );
            if (found == dict.end()) {
                // is name already in use?
                if (dict.find(name) == dict.end()) {
                    dict.add(name, bitId);
                }
            }
        }
    );
}

MaskDict::~MaskDict() noexcept = default;

std::shared_ptr<MaskDict> MaskDict::clone() const {
    return GlobalState::get().copy(*this);
}

int MaskDict::getUnusedPlane() const {
    if (empty()) {
        return 0;
    }

    auto const maxIter = std::max_element(
        begin(), end(),
        [](auto const & a, auto const & b) { return a.second < b.second; }
    );
    assert(maxIter != end());
    int id = maxIter->second + 1;  // The maskPlane to use if there are no gaps

    for (int i = 0; i < id; ++i) {
        // is i already used in this Mask?
        auto const sameIter = std::find_if(
            begin(), end(),
            [i](auto const & item) { return item.second == i; }
        );
        if (sameIter == end()) {  // Not used; so we'll use it
            return i;
        }
    }

    return id;
}

int MaskDict::getMaskPlane(std::string const & name) const {
    auto iter = find(name);
    return (iter == end()) ? -1 : iter->second;
}

void MaskDict::print() const {
    for (auto const & item : *this) {
        std::cout << "Plane " << item.second << " -> " << item.first << std::endl;
    }
}

bool MaskDict::operator==(MaskDict const& rhs) const {
    return this == &rhs || (_hash == rhs._hash && _dict == rhs._dict);
}

void MaskDict::add(std::string const & name, int bitId) {
    _dict[name] = bitId;
    _hash = boost::hash<MaskPlaneDict>()(_dict);
}

void MaskDict::erase(std::string const & name) {
    _dict.erase(name);
    _hash = boost::hash<MaskPlaneDict>()(_dict);
}

void MaskDict::clear() {
    _dict.clear();
    _hash = 0x0;
}

void MaskDict::_addInitialMaskPlanes() {
    int i = -1;
    _dict["BAD"] = ++i;
    _dict["SAT"] = ++i;
    _dict["INTRP"] = ++i;
    _dict["CR"] = ++i;
    _dict["EDGE"] = ++i;
    _dict["DETECTED"] = ++i;
    _dict["DETECTED_NEGATIVE"] = ++i;
    _dict["SUSPECT"] = ++i;
    _dict["NO_DATA"] = ++i;
    _hash = boost::hash<MaskPlaneDict>()(_dict);
}

MaskDict::MaskDict() : _dict(), _hash(0x0) {}

MaskDict::MaskDict(MaskPlaneDict const & dict) : _dict(dict), _hash(boost::hash<MaskPlaneDict>()(_dict)) {}

}}}} // lsst::afw::image::detail