python.h

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/*
 * This file is part of afw.
 *
 * 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/>.
 */
 
#ifndef LSST_AFW_TYPEHANDLING_PYTHON_H
#define LSST_AFW_TYPEHANDLING_PYTHON_H
 
#include "pybind11/pybind11.h"
 
#include <string>
 
#include "lsst/afw/typehandling/Storable.h"
#include "lsst/afw/formatters/Utils.h"
#include "lsst/afw/table/io/CatalogVector.h"
#include "lsst/afw/table/io/OutputArchive.h"
#include "lsst/afw/table/io/Persistable.cc"
 
namespace lsst {
namespace afw {
namespace typehandling {

template <class Base = Storable>
class StorableHelper : public Base, public pybind11::trampoline_self_life_support {
public:
    using Base::Base;

    template<typename... Args>
    explicit StorableHelper<Base>(Args... args) : Base(args...) {}
 
    std::shared_ptr<Storable> cloneStorable() const override {
        /* __deepcopy__ takes an optional dict, but PYBIND11_OVERLOAD_* won't
         * compile unless you give it arguments that work for the C++ method
         */
        PYBIND11_OVERLOAD_NAME(std::shared_ptr<Storable>, Base, "__deepcopy__", cloneStorable, );
    }
 
    std::string toString() const override {
        PYBIND11_OVERLOAD_NAME(std::string, Base, "__repr__", toString, );
    }
 
    std::size_t hash_value() const override {
        PYBIND11_OVERLOAD_NAME(std::size_t, Base, "__hash__", hash_value, );
    }
 
    bool equals(Storable const& other) const noexcept override {
        PYBIND11_OVERLOAD_NAME(bool, Base, "__eq__", equals, other);
    }
 
    bool isPersistable() const noexcept override {
        PYBIND11_OVERLOAD(
            bool, Base, isPersistable
        );
    }
 
    std::string getPersistenceName() const override {
        PYBIND11_OVERLOAD_NAME(
            std::string, Base, "_getPersistenceName", getPersistenceName
        );
    }
 
    std::string getPythonModule() const override {
        PYBIND11_OVERLOAD_NAME(
            std::string, Base, "_getPythonModule", getPythonModule
        );
    }
 
    void write(table::io::OutputArchiveHandle& handle) const override;
};
 
std::string declareGenericMapRestrictions(std::string const& className, std::string const& keyName);

 
namespace {
 
class StorableHelperPersistenceHelper {
public:
    table::Schema schema;
    table::Key<table::Array<std::uint8_t>> bytes;
 
    static StorableHelperPersistenceHelper const &get() {
        static StorableHelperPersistenceHelper instance;
        return instance;
    }
 
    // No copying
    StorableHelperPersistenceHelper(StorableHelperPersistenceHelper const &) = delete;
    StorableHelperPersistenceHelper &operator=(StorableHelperPersistenceHelper const &) = delete;
 
    // No moving
    StorableHelperPersistenceHelper(StorableHelperPersistenceHelper &&) = delete;
    StorableHelperPersistenceHelper &operator=(StorableHelperPersistenceHelper &&) = delete;
 
private:
    StorableHelperPersistenceHelper() :
        schema(),
        bytes(schema.addField<table::Array<std::uint8_t>>(
            "bytes", "an opaque bytestring representation of a Storable", ""
        ))
    {}
};
 
 
class StorableHelperFactory : public table::io::PersistableFactory {
public:
    StorableHelperFactory(std::string const &module, std::string const &name) :
        table::io::PersistableFactory(name),
        _module(module),
        _name(name)
    {}
 
    std::shared_ptr<table::io::Persistable> read(
        InputArchive const &archive,
        CatalogVector const &catalogs
    ) const override {
        pybind11::gil_scoped_acquire gil;
        auto const &keys = StorableHelperPersistenceHelper::get();
        LSST_ARCHIVE_ASSERT(catalogs.size() == 1u);
        LSST_ARCHIVE_ASSERT(catalogs.front().size() == 1u);
        LSST_ARCHIVE_ASSERT(catalogs.front().getSchema() == keys.schema);
        auto const &record = catalogs.front().front();
        std::string stringRep = formatters::bytesToString(record.get(keys.bytes));
        auto cls = pybind11::module::import(_module.c_str()).attr(_name.c_str());
        auto pyobj = cls.attr("_read")(pybind11::bytes(stringRep));
        return pyobj.cast<std::shared_ptr<Storable>>();
    }
 
private:
    std::string _module;
    std::string _name;
};
 
}  // namespace
 
 
template <typename Base>
void StorableHelper<Base>::write(table::io::OutputArchiveHandle& handle) const {
    pybind11::gil_scoped_acquire gil;
    pybind11::function overload = pybind11::get_overload(static_cast<const Base *>(this), "_write");
    if (!overload)
        throw std::runtime_error("Cannot find StorableHelper _write overload");
    auto o = overload().cast<std::string>();
    auto const &keys = StorableHelperPersistenceHelper::get();
    table::BaseCatalog cat = handle.makeCatalog(keys.schema);
    std::shared_ptr<table::BaseRecord> record = cat.addNew();
    record->set(keys.bytes, formatters::stringToBytes(o));
    handle.saveCatalog(cat);
}
 
}  // namespace typehandling
}  // namespace afw
}  // namespace lsst
 
#endif