/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_mscom_ActivationContext_h
#define mozilla_mscom_ActivationContext_h

#include <utility>

#include "mozilla/Attributes.h"

#if defined(MOZILLA_INTERNAL_API)
#  include "mozilla/ResultVariant.h"
#  include "nsString.h"
#endif  // defined(MOZILLA_INTERNAL_API)

#include <windows.h>

namespace mozilla {
namespace mscom {

class ActivationContext final {
 public:
  // This is the default resource ID that the Windows dynamic linker searches
  // for when seeking a manifest while loading a DLL.
  static constexpr WORD kDllManifestDefaultResourceId = 2;

  ActivationContext() : mActCtx(INVALID_HANDLE_VALUE) {}

  explicit ActivationContext(WORD aResourceId);
  explicit ActivationContext(HMODULE aLoadFromModule,
                             WORD aResourceId = kDllManifestDefaultResourceId);

  ActivationContext(ActivationContext&& aOther);
  ActivationContext& operator=(ActivationContext&& aOther);

  ActivationContext(const ActivationContext& aOther);
  ActivationContext& operator=(const ActivationContext& aOther);

  ~ActivationContext();

  explicit operator bool() const { return mActCtx != INVALID_HANDLE_VALUE; }

#if defined(MOZILLA_INTERNAL_API)
  static Result<uintptr_t, HRESULT> GetCurrent();
  static HRESULT GetCurrentManifestPath(nsAString& aOutManifestPath);
#endif  // defined(MOZILLA_INTERNAL_API)

 private:
  void Init(ACTCTX& aActCtx);
  void AddRef();
  void Release();

 private:
  HANDLE mActCtx;

  friend class ActivationContextRegion;
};

class MOZ_NON_TEMPORARY_CLASS ActivationContextRegion final {
 public:
  template <typename... Args>
  explicit ActivationContextRegion(Args&&... aArgs)
      : mActCtx(std::forward<Args>(aArgs)...), mActCookie(0) {
    Activate();
  }

  ActivationContextRegion();

  explicit ActivationContextRegion(const ActivationContext& aActCtx);
  ActivationContextRegion& operator=(const ActivationContext& aActCtx);

  explicit ActivationContextRegion(ActivationContext&& aActCtx);
  ActivationContextRegion& operator=(ActivationContext&& aActCtx);

  ActivationContextRegion(ActivationContextRegion&& aRgn);
  ActivationContextRegion& operator=(ActivationContextRegion&& aRgn);

  ~ActivationContextRegion();

  explicit operator bool() const { return !!mActCookie; }

  ActivationContextRegion(const ActivationContextRegion&) = delete;
  ActivationContextRegion& operator=(const ActivationContextRegion&) = delete;

  bool Deactivate();

 private:
  void Activate();

  ActivationContext mActCtx;
  ULONG_PTR mActCookie;
};

}  // namespace mscom
}  // namespace mozilla

#endif  // mozilla_mscom_ActivationContext_h