gecko-dev/xpcom/components/nsComponentManagerUtils.h

/* -*- 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 nsComponentManagerUtils_h__
#define nsComponentManagerUtils_h__

#include "nscore.h"
#include "nsCOMPtr.h"

#include "nsIFactory.h"

nsresult CallCreateInstance(const nsCID& aCID, const nsIID& aIID,
                            void** aResult);

nsresult CallCreateInstance(const char* aContractID, const nsIID& aIID,
                            void** aResult);

nsresult CallGetClassObject(const nsCID& aCID, const nsIID& aIID,
                            void** aResult);

nsresult CallGetClassObject(const char* aContractID, const nsIID& aIID,
                            void** aResult);

class MOZ_STACK_CLASS nsCreateInstanceByCID final : public nsCOMPtr_helper {
 public:
  nsCreateInstanceByCID(const nsCID& aCID, nsresult* aErrorPtr)
      : mCID(aCID), mErrorPtr(aErrorPtr) {}

  virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const override;

 private:
  const nsCID& mCID;
  nsresult* mErrorPtr;
};

class MOZ_STACK_CLASS nsCreateInstanceByContractID final
    : public nsCOMPtr_helper {
 public:
  nsCreateInstanceByContractID(const char* aContractID, nsresult* aErrorPtr)
      : mContractID(aContractID), mErrorPtr(aErrorPtr) {}

  virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const override;

 private:
  const char* mContractID;
  nsresult* mErrorPtr;
};

class MOZ_STACK_CLASS nsCreateInstanceFromFactory final
    : public nsCOMPtr_helper {
 public:
  nsCreateInstanceFromFactory(nsIFactory* aFactory, nsresult* aErrorPtr)
      : mFactory(aFactory), mErrorPtr(aErrorPtr) {}

  virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const override;

 private:
  nsIFactory* MOZ_NON_OWNING_REF mFactory;
  nsresult* mErrorPtr;
};

inline const nsCreateInstanceByCID do_CreateInstance(const nsCID& aCID,
                                                     nsresult* aError = 0) {
  return nsCreateInstanceByCID(aCID, aError);
}

inline const nsCreateInstanceByContractID do_CreateInstance(
    const char* aContractID, nsresult* aError = 0) {
  return nsCreateInstanceByContractID(aContractID, aError);
}

inline const nsCreateInstanceFromFactory do_CreateInstance(
    nsIFactory* aFactory, nsresult* aError = 0) {
  return nsCreateInstanceFromFactory(aFactory, aError);
}

class MOZ_STACK_CLASS nsGetClassObjectByCID final : public nsCOMPtr_helper {
 public:
  nsGetClassObjectByCID(const nsCID& aCID, nsresult* aErrorPtr)
      : mCID(aCID), mErrorPtr(aErrorPtr) {}

  virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const override;

 private:
  const nsCID& mCID;
  nsresult* mErrorPtr;
};

class MOZ_STACK_CLASS nsGetClassObjectByContractID final
    : public nsCOMPtr_helper {
 public:
  nsGetClassObjectByContractID(const char* aContractID, nsresult* aErrorPtr)
      : mContractID(aContractID), mErrorPtr(aErrorPtr) {}

  virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const override;

 private:
  const char* mContractID;
  nsresult* mErrorPtr;
};

/**
 * do_GetClassObject can be used to improve performance of callers
 * that call |CreateInstance| many times.  They can cache the factory
 * and call do_CreateInstance or CallCreateInstance with the cached
 * factory rather than having the component manager retrieve it every
 * time.
 */
inline const nsGetClassObjectByCID do_GetClassObject(const nsCID& aCID,
                                                     nsresult* aError = 0) {
  return nsGetClassObjectByCID(aCID, aError);
}

inline const nsGetClassObjectByContractID do_GetClassObject(
    const char* aContractID, nsresult* aError = 0) {
  return nsGetClassObjectByContractID(aContractID, aError);
}

// type-safe shortcuts for calling |CreateInstance|
template <class DestinationType>
inline nsresult CallCreateInstance(const nsCID& aClass,
                                   DestinationType** aDestination) {
  MOZ_ASSERT(aDestination, "null parameter");

  return CallCreateInstance(aClass, NS_GET_IID(DestinationType),
                            reinterpret_cast<void**>(aDestination));
}

template <class DestinationType>
inline nsresult CallCreateInstance(const char* aContractID,
                                   DestinationType** aDestination) {
  MOZ_ASSERT(aContractID, "null parameter");
  MOZ_ASSERT(aDestination, "null parameter");

  return CallCreateInstance(aContractID, NS_GET_IID(DestinationType),
                            reinterpret_cast<void**>(aDestination));
}

template <class DestinationType>
inline nsresult CallCreateInstance(nsIFactory* aFactory,
                                   DestinationType** aDestination) {
  MOZ_ASSERT(aFactory, "null parameter");
  MOZ_ASSERT(aDestination, "null parameter");

  return aFactory->CreateInstance(nullptr, NS_GET_IID(DestinationType),
                                  reinterpret_cast<void**>(aDestination));
}

template <class DestinationType>
inline nsresult CallGetClassObject(const nsCID& aClass,
                                   DestinationType** aDestination) {
  MOZ_ASSERT(aDestination, "null parameter");

  return CallGetClassObject(aClass, NS_GET_IID(DestinationType),
                            reinterpret_cast<void**>(aDestination));
}

template <class DestinationType>
inline nsresult CallGetClassObject(const char* aContractID,
                                   DestinationType** aDestination) {
  MOZ_ASSERT(aDestination, "null parameter");

  return CallGetClassObject(aContractID, NS_GET_IID(DestinationType),
                            reinterpret_cast<void**>(aDestination));
}

#endif /* nsComponentManagerUtils_h__ */