functor.hpp

#pragma once

#include <utility>
#include <memory>
#include <sdbusplus/bus.hpp>
#include "utils.hpp"
#include "types.hpp"

namespace phosphor
{
namespace inventory
{
namespace manager
{

class Manager;

/** @brief make_action
 *
 *  Adapt an action function object.
 *
 *  @param[in] action - The action being adapted.
 *  @returns - The adapted action.
 *
 *  @tparam T - The type of the action being adapted.
 */
template <typename T> auto make_action(T&& action)
{
    return Action(std::forward<T>(action));
}

/** @brief make_filter
 *
 *  Adapt a filter function object.
 *
 *  @param[in] filter - The filter being adapted.
 *  @returns - The adapted filter.
 *
 *  @tparam T - The type of the filter being adapted.
 */
template <typename T> auto make_filter(T&& filter)
{
    return Filter(std::forward<T>(filter));
}

/** @brief make_path_condition
 *
 *  Adapt a path_condition function object.
 *
 *  @param[in] filter - The functor being adapted.
 *  @returns - The adapted functor.
 *
 *  @tparam T - The type of the functor being adapted.
 */
template <typename T> auto make_path_condition(T&& condition)
{
    return PathCondition(std::forward<T>(condition));
}

template <typename T, typename... Args>
auto callArrayWithStatus(T&& container, Args&&... args)
{
    for (auto f : container)
    {
        if (!f(std::forward<Args>(args)...))
        {
            return false;
        }
    }
    return true;
}

namespace functor
{

/** @brief Destroy objects action.  */
inline auto destroyObjects(std::vector<const char*>&& paths,
                           std::vector<PathCondition>&& conditions)
{
    return [=](auto& b, auto& m) {
        for (const auto& p : paths)
        {
            if (callArrayWithStatus(conditions, p, b, m))
            {
                m.destroyObjects({p});
            }
        }
    };
}

/** @brief Create objects action.  */
inline auto
    createObjects(std::map<sdbusplus::message::object_path, Object>&& objs)
{
    return [=](auto&, auto& m) { m.createObjects(objs); };
}

/** @brief Set a property action.
 *
 *  Invoke the requested method with a reference to the requested
 *  sdbusplus server binding interface as a parameter.
 *
 *  @tparam T - The sdbusplus server binding interface type.
 *  @tparam U - The type of the sdbusplus server binding member
 *      function that sets the property.
 *  @tparam V - The property value type.
 *
 *  @param[in] paths - The DBus paths on which the property should
 *      be set.
 *  @param[in] iface - The DBus interface hosting the property.
 *  @param[in] member - Pointer to sdbusplus server binding member.
 *  @param[in] value - The value the property should be set to.
 *
 *  @returns - A function object that sets the requested property
 *      to the requested value.
 */
template <typename T, typename U, typename V>
auto setProperty(std::vector<const char*>&& paths,
                 std::vector<PathCondition>&& conditions, const char* iface,
                 U&& member, V&& value)
{
    // The manager is the only parameter passed to actions.
    // Bind the path, interface, interface member function pointer,
    // and value to a lambda.  When it is called, forward the
    // path, interface and value on to the manager member function.
    return [
        paths, conditions = conditions, iface, member,
        value = std::forward<V>(value)
    ](auto& b, auto& m)
    {
        for (auto p : paths)
        {
            if (callArrayWithStatus(conditions, p, b, m))
            {
                m.template invokeMethod<T>(p, iface, member, value);
            }
        }
    };
}

/** @struct PropertyChangedCondition
 *  @brief Match filter functor that tests a property value.
 *
 *  @tparam T - The type of the property being tested.
 *  @tparam U - The type of the condition checking functor.
 */
template <typename T, typename U> struct PropertyChangedCondition
{
    PropertyChangedCondition() = delete;
    ~PropertyChangedCondition() = default;
    PropertyChangedCondition(const PropertyChangedCondition&) = default;
    PropertyChangedCondition&
        operator=(const PropertyChangedCondition&) = default;
    PropertyChangedCondition(PropertyChangedCondition&&) = default;
    PropertyChangedCondition& operator=(PropertyChangedCondition&&) = default;
    PropertyChangedCondition(const char* iface, const char* property,
                             U&& condition) :
        _iface(iface),
        _property(property), _condition(std::forward<U>(condition))
    {
    }

    /** @brief Test a property value.
     *
     * Extract the property from the PropertiesChanged
     * message and run the condition test.
     */
    bool operator()(sdbusplus::bus::bus&, sdbusplus::message::message& msg,
                    Manager&) const
    {
        std::map<std::string, sdbusplus::message::variant<T>> properties;
        const char* iface = nullptr;

        msg.read(iface);
        if (!iface || strcmp(iface, _iface))
        {
            return false;
        }

        msg.read(properties);
        auto it = properties.find(_property);
        if (it == properties.cend())
        {
            return false;
        }

        return _condition(std::forward<T>(it->second.template get<T>()));
    }

  private:
    const char* _iface;
    const char* _property;
    U _condition;
};

/** @struct PropertyConditionBase
 *  @brief Match filter functor that tests a property value.
 *
 *  Base class for PropertyCondition - factored out code that
 *  doesn't need to be templated.
 */
struct PropertyConditionBase
{
    PropertyConditionBase() = delete;
    virtual ~PropertyConditionBase() = default;
    PropertyConditionBase(const PropertyConditionBase&) = default;
    PropertyConditionBase& operator=(const PropertyConditionBase&) = default;
    PropertyConditionBase(PropertyConditionBase&&) = default;
    PropertyConditionBase& operator=(PropertyConditionBase&&) = default;

    /** @brief Constructor
     *
     *  The service argument can be nullptr.  If something
     *  else is provided the function will call the the
     *  service directly.  If omitted, the function will
     *  look up the service in the ObjectMapper.
     *
     *  @param path - The path of the object containing
     *     the property to be tested.
     *  @param iface - The interface hosting the property
     *     to be tested.
     *  @param property - The property to be tested.
     *  @param service - The DBus service hosting the object.
     */
    PropertyConditionBase(const char* path, const char* iface,
                          const char* property, const char* service) :
        _path(path ? path : std::string()),
        _iface(iface), _property(property), _service(service)
    {
    }

    /** @brief Forward comparison to type specific implementation. */
    virtual bool eval(sdbusplus::message::message&) const = 0;

    /** @brief Test a property value.
     *
     * Make a DBus call and test the value of any property.
     */
    bool operator()(sdbusplus::bus::bus&, sdbusplus::message::message&,
                    Manager&) const;

    /** @brief Test a property value.
     *
     * Make a DBus call and test the value of any property.
     */
    bool operator()(const std::string&, sdbusplus::bus::bus&, Manager&) const;

  private:
    std::string _path;
    std::string _iface;
    std::string _property;
    const char* _service;
};

/** @struct PropertyCondition
 *  @brief Match filter functor that tests a property value.
 *
 *  @tparam T - The type of the property being tested.
 *  @tparam U - The type of the condition checking functor.
 */
template <typename T, typename U>
struct PropertyCondition final : public PropertyConditionBase
{
    PropertyCondition() = delete;
    ~PropertyCondition() = default;
    PropertyCondition(const PropertyCondition&) = default;
    PropertyCondition& operator=(const PropertyCondition&) = default;
    PropertyCondition(PropertyCondition&&) = default;
    PropertyCondition& operator=(PropertyCondition&&) = default;

    /** @brief Constructor
     *
     *  The service argument can be nullptr.  If something
     *  else is provided the function will call the the
     *  service directly.  If omitted, the function will
     *  look up the service in the ObjectMapper.
     *
     *  @param path - The path of the object containing
     *     the property to be tested.
     *  @param iface - The interface hosting the property
     *     to be tested.
     *  @param property - The property to be tested.
     *  @param condition - The test to run on the property.
     *  @param service - The DBus service hosting the object.
     */
    PropertyCondition(const char* path, const char* iface, const char* property,
                      U&& condition, const char* service) :
        PropertyConditionBase(path, iface, property, service),
        _condition(std::forward<decltype(condition)>(condition))
    {
    }

    /** @brief Test a property value.
     *
     * Make a DBus call and test the value of any property.
     */
    bool eval(sdbusplus::message::message& msg) const override
    {
        sdbusplus::message::variant<T> value;
        msg.read(value);
        return _condition(std::forward<T>(value.template get<T>()));
    }

  private:
    U _condition;
};

/** @brief Implicit type deduction for constructing PropertyChangedCondition. */
template <typename T>
auto propertyChangedTo(const char* iface, const char* property, T&& val)
{
    auto condition = [val = std::forward<T>(val)](T && arg)
    {
        return arg == val;
    };
    using U = decltype(condition);
    return PropertyChangedCondition<T, U>(iface, property,
                                          std::move(condition));
}

/** @brief Implicit type deduction for constructing PropertyCondition.  */
template <typename T>
auto propertyIs(const char* path, const char* iface, const char* property,
                T&& val, const char* service = nullptr)
{
    auto condition = [val = std::forward<T>(val)](T && arg)
    {
        return arg == val;
    };
    using U = decltype(condition);
    return PropertyCondition<T, U>(path, iface, property, std::move(condition),
                                   service);
}
} // namespace functor
} // namespace manager
} // namespace inventory
} // namespace phosphor

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