nf7/iface/common/container.hh

143 lines
3.9 KiB
C++

// No copyright
#pragma once
#include <cassert>
#include <cstdint>
#include <functional>
#include <memory>
#include <typeindex>
#include <unordered_map>
#include <utility>
#include <vector>
#include "iface/common/exception.hh"
namespace nf7 {
template <typename I>
class Container {
public:
Container() = default;
virtual ~Container() = default;
Container(const Container&) = delete;
Container(Container&&) = delete;
Container& operator=(const Container&) = delete;
Container& operator=(Container&&) = delete;
virtual std::shared_ptr<I> Get(std::type_index) = 0;
virtual bool installed(std::type_index) const noexcept = 0;
template <typename I2>
void Get(std::shared_ptr<I2>& out) {
out = Get<I2>();
}
template <typename I2>
std::shared_ptr<I2> Get() {
auto ptr = GetOr<I2>();
if (nullptr == ptr) {
throw Exception {"missing dependency"};
}
return ptr;
}
template <typename I2>
void GetOr(std::shared_ptr<I2>& out,
const std::shared_ptr<I2>& def = nullptr) {
out = GetOr<I2>(def);
}
template <typename I2>
std::shared_ptr<I2> GetOr(const std::shared_ptr<I2>& def = nullptr) {
auto ptr = GetOr(typeid(I2), def);
auto casted_ptr = std::dynamic_pointer_cast<I2>(ptr);
assert(nullptr == ptr || nullptr != casted_ptr);
return casted_ptr;
}
std::shared_ptr<I> GetOr(std::type_index idx, const std::shared_ptr<I>& def) {
const auto& ret = Get(idx);
return nullptr != ret? ret: def;
}
template <typename T>
bool installed() const noexcept {
return installed(typeid(T));
}
};
template <typename I>
class SimpleContainer : public Container<I> {
public:
using Factory = std::function<std::shared_ptr<I>(Container<I>&)>;
template <typename I2, typename T>
static std::pair<std::type_index, Factory> MakePair() noexcept {
static_assert(std::is_base_of_v<I, I2>,
"registerable interface must be based on "
"container common interface");
static_assert(std::is_base_of_v<I2, T>,
"registerable concrete type must be based on "
"an interface to be being registered");
static_assert(std::is_constructible_v<T, Container<I>&>,
"registerable concrete type must be "
"constructible with container");
return std::pair<std::type_index, Factory>{
typeid(I2), [](auto& x) { return std::make_shared<T>(x); }};
}
static std::shared_ptr<Container<I>> Make(
std::unordered_map<std::type_index, Factory>&& factories) {
try {
return std::make_shared<Container<I>>(std::move(factories));
} catch (const std::bad_alloc&) {
throw Exception {"memory shortage"};
}
}
SimpleContainer() = delete;
explicit SimpleContainer(
std::unordered_map<std::type_index, Factory>&& factories) noexcept
: factories_(std::move(factories)) { }
std::shared_ptr<I> Get(std::type_index idx) override {
const auto obj_itr = objs_.find(idx);
if (objs_.end() != obj_itr) {
return obj_itr->second;
}
const auto factory_itr = factories_.find(idx);
if (factories_.end() != factory_itr) {
assert(nest_ < 1000 &&
"circular dependency detected in container factory");
++nest_;
auto obj = factory_itr->second(*this);
--nest_;
try {
const auto [itr, added] = objs_.insert({idx, std::move(obj)});
(void) itr;
(void) added;
assert(added);
return itr->second;
} catch (...) {
throw Exception {"memory shortage"};
}
}
return nullptr;
}
bool installed(std::type_index idx) const noexcept override {
return factories_.contains(idx);
}
using Container<I>::Get;
using Container<I>::GetOr;
using Container<I>::installed;
private:
std::unordered_map<std::type_index, Factory> factories_;
std::unordered_map<std::type_index, std::shared_ptr<I>> objs_;
uint32_t nest_ = 0;
};
} // namespace nf7