salmanoff/hcore/include/senseApis/senseApiLib.h

#ifndef SENSE_API_PROVIDER_DESC_H
#define SENSE_API_PROVIDER_DESC_H

#include <string>
#include <memory>
#include <vector>
#include <dlfcn.h>
#include <functional>
#include <user/senseApiDesc.h>

namespace hk {
namespace sense_api {

/* C++ version of the C struct above, which Harikoff uses to manage the
 * lib and connect implexors to it.
 */
class SenseApiDesc
{
public:
    class ExportedImplexorApiDesc
    {
    public:
        ExportedImplexorApiDesc(const CExportedImplexorApiDesc& cDesc)
        // The caller should sanity check before calling this constructor.
        :   name(cDesc.name)
        {}

        const std::string name;
    };

public:
    SenseApiDesc() = default;
    SenseApiDesc(const CSenseApiDesc& cDesc)
    // The caller should sanity check before calling this constructor.
    :   name(cDesc.name)
    {
        for (uint32_t i = 0; i < cDesc.numExportedImplexorApis; ++i)
        {
            if (!CExportedImplexorApiDesc_sanityCheck(
                &cDesc.exportedImplexorApis[i]))
            {
                throw std::runtime_error(
                    "Sanity check failed for exported implexor API descriptor");
            }

            exportedImplexorApis.push_back(
                ExportedImplexorApiDesc(cDesc.exportedImplexorApis[i]));
        }
    }

    std::string name;
    // These are the implexors whose APIs this lib exports.
    std::vector<ExportedImplexorApiDesc> exportedImplexorApis;
};

class SenseApiLib
{
public:
    SenseApiLib(
        const std::string& path, void *_dlopen_handle, getSenseApiDescFn *descFn)
    :   libraryPath(path),
        dlopen_handle(
            _dlopen_handle, reinterpret_cast<void(*)(void*)>(&dlclose)),
        HK_GET_SENSE_API_DESC_FN_NAME(descFn)
    {}

    void setSenseApiDesc(const CSenseApiDesc* desc)
    {
        if (!CSenseApiDesc_sanityCheck(desc) ||
            !Csal_libMgmtOps_sanityCheck(desc->sal_libMgmtOps))
        {
            throw std::runtime_error(
                std::string(__func__) + ": Sanity check failed for sense API "
                "descriptor in library '" + libraryPath + "'");
        }
        for (uint32_t i = 0; i < desc->numExportedImplexorApis; ++i)
        {
            if (!CExportedImplexorApiDesc_sanityCheck(
                &desc->exportedImplexorApis[i]))
            {
                throw std::runtime_error(
                    std::string(__func__) + ": Sanity check failed for "
                    "exported implexor API descriptor in library '"
                    + libraryPath + "'");
            }
        }
        new (&senseApiDesc) SenseApiDesc(*desc); // Placement new
    }

public:
    std::string libraryPath;
    std::unique_ptr<void, void(*)(void*)> dlopen_handle;
    /* UNIMPLEMENTED: API-specific cmdline options. These affect this specific
     * sense api lib's behaviour globally.
     */
    std::vector<std::string> options;

    /**
     * @brief Every sense API lib is required to provide a function that returns
     * a CSenseApiDesc struct. This struct states which API the lib uses to
     * connect Harikoff to the sense provider it supports.
     *
     * This getter function should be visible to dlsym() so that Harikoff can
     * find it in the lib after loading it, and call it.
     */
    std::function<getSenseApiDescFn> HK_GET_SENSE_API_DESC_FN_NAME;

    /**
     * @brief Harikoff will call the `HK_GET_SENSE_API_DESC_FN_NAME` getter
     * function and use the data it provides in order to fill out this
     * descriptor.
     */
    SenseApiDesc senseApiDesc;
};

} // namespace sense_api
} // namespace hk

#endif // SENSE_API_PROVIDER_DESC_H