connect.h

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// -*- mode: C++; c-file-style: "virtutech-c++" -*-
 
/*
  © 2021 Intel Corporation
 
  This software and the related documents are Intel copyrighted materials, and
  your use of them is governed by the express license under which they were
  provided to you ("License"). Unless the License provides otherwise, you may
  not use, modify, copy, publish, distribute, disclose or transmit this software
  or the related documents without Intel's prior written permission.
 
  This software and the related documents are provided as is, with no express or
  implied warranties, other than those that are expressly stated in the License.
*/
 
#ifndef SIMICS_CONNECT_H
#define SIMICS_CONNECT_H
 
#include <simics/base/log.h>  // SIM_LOG_INFO
#include <tuple>
#include <string>
#include <set>
#include <stdexcept>  // runtime_error
#include <cassert>
 
#include "conf-object.h"
#include "detail/attribute-exceptions.h"  // InterfaceNotFound
 
namespace simics {
 
class ConnectBase {
  public:
    ConnectBase() : obj_(nullptr) {}
    virtual ~ConnectBase() = default;
 
    virtual bool set(const ConfObjectRef &o) = 0;
    ConfObjectRef get() const { return obj_; }
    operator conf_object_t*() const { return obj_.object(); }
 
  protected:
    ConfObjectRef obj_;
};
 
class ConnectConfig {
  public:
    ConnectConfig() = default;
 
    bool is_optional(const std::string &iface_name) const {
        return optional_ifaces_.find(iface_name) \
            != optional_ifaces_.end();
    }
 
    template<typename FirstIface, typename... RestIfaces>
    static ConnectConfig optional() {
        ConnectConfig config;
        config.mark_optional<FirstIface, RestIfaces...>();
        return config;
    }
 
  private:
    template<typename T>
    void mark_optional() {
        optional_ifaces_.insert(typename T::Info().name());
    }
 
    // The variadic template
    template<typename FirstIface, typename... RestIfaces>
    typename std::enable_if<sizeof...(RestIfaces) != 0, void>::type
    mark_optional() {
        optional_ifaces_.insert(typename FirstIface::Info().name());
        mark_optional<RestIfaces...>();
    }
 
    std::set<std::string> optional_ifaces_;
};
 
template<typename FirstIface, typename... RestIfaces>
class Connect : public ConnectBase {
  public:
    typedef std::tuple<typename FirstIface::ToC,
                       typename RestIfaces::ToC...> ifaces_type;
    Connect() = default;
    explicit Connect(const ConnectConfig &config) : config_(config) {}
 
    explicit Connect(const ConfObjectRef &device) : device_(device) {}
    Connect(const ConfObjectRef &device, const ConnectConfig &config)
        : device_(device), config_(config) {}
 
    // ConnectBase
    bool set(const ConfObjectRef &o) override {
        if (obj_ == o) {
            return true;
        }
 
        if (!o) {
            ifaces_ = ifaces_type();
            obj_ = o;
            return true;
        }
 
        try {
            set_ifaces<FirstIface, RestIfaces...>(o);
        } catch (const detail::SetInterfaceNotFound &e) {
            if (device_) {
                SIM_LOG_INFO(1, device_, 0, "%s", e.what());
            } else {
                SIM_LOG_INFO(1, SIM_get_object("sim"), 0, "%s", e.what());
            }
            ifaces_ = ifaces_type();
            return false;
        }
 
        obj_ = o;
        return true;
    }
 
    template<typename T>
    typename std::enable_if<sizeof...(RestIfaces) != 0,
                            const typename T::ToC>::type
    iface() const {
        return std::get<typename T::ToC>(ifaces_);
    }
 
    const typename FirstIface::ToC &iface() const {
        return std::get<typename FirstIface::ToC>(ifaces_);
    }
 
  protected:
    conf_object_t *device() const {
        if (device_ == nullptr) {
            SIM_LOG_ERROR(SIM_get_object("sim"), 0,
                          "Device is not set, should be set from the CTOR");
        }
        return device_;
    }
 
  private:
    template<typename T>
    const typename T::ctype *interface_(const ConfObjectRef &o) const {
        std::string iface_name = typename T::Info().name();
        auto iface = static_cast<const typename T::ctype *>(
                o.get_interface(iface_name));
        if (!iface && !config_.is_optional(iface_name)) {
            throw detail::SetInterfaceNotFound {
                "Interface " + iface_name + " not found in " + o.name()
            };
        }
        return iface;
    }
 
    template<typename T>
    void set_ifaces(const ConfObjectRef &o) {
        std::get<typename T::ToC>(ifaces_) = \
            typename T::ToC(o.object(), interface_<T>(o));
    }
 
    // The variadic template
    template<typename First, typename... Rest>
    typename std::enable_if<sizeof...(Rest) != 0, void>::type
    set_ifaces(const ConfObjectRef &o) {
        std::get<typename First::ToC>(ifaces_) = \
            typename First::ToC(o.object(), interface_<First>(o));
        set_ifaces<Rest...>(o);
    }
 
    ifaces_type ifaces_;
    conf_object_t *device_ {nullptr};
    ConnectConfig config_;
};
 
}  // namespace simics
 
#endif