promise.h

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#pragma once
 
#include <functional>
 
#include <millicast-sdk/error.h>
#include <millicast-sdk/exports.h>
 
namespace millicast {
 
namespace detail {
template <typename T>
struct PromiseResultCbType {
  using Type = std::function<void(T&&)>;
};
 
template <>
struct PromiseResultCbType<void> {
  using Type = std::function<void()>;
};
 
template <typename T>
class PromiseImpl {
 public:
  virtual ~PromiseImpl() = default;
  virtual void on_result(
      const typename detail::PromiseResultCbType<T>::Type& cb) = 0;
  virtual void on_error(const std::function<void(const Error&)>& cb) = 0;
};
}  // namespace detail
 
template <typename T>
class MILLICAST_TEMPLATE_API Promise {
 public:
  Promise(std::unique_ptr<detail::PromiseImpl<T>> impl)
      : _impl(std::move(impl)){};
  Promise(const Promise&) = delete;
  Promise(Promise&&) = delete;
  Promise& operator=(const Promise&) = delete;
  Promise& operator=(Promise&&) = delete;
 
  Promise<T>& on_result(
      const typename detail::PromiseResultCbType<T>::Type& cb) {
    _impl->on_result(cb);
    return *this;
  }
 
  Promise<T>& on_error(const std::function<void(const Error&)>& cb) {
    _impl->on_error(cb);
    return *this;
  }
 
  void done() { _impl = {}; }
 
 private:
  std::unique_ptr<detail::PromiseImpl<T>> _impl;
};
}  // namespace millicast