services/common/app_services_logger/AppServicesLoggerComponents.h

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #ifndef mozilla_services_AppServicesLoggerComponents_h_
   6 #define mozilla_services_AppServicesLoggerComponents_h_
   7
   8 #include "mozIAppServicesLogger.h"
   9 #include "nsCOMPtr.h"
  10
  11 extern "C" {
  12
  13 // Implemented in Rust, in the `app_services_logger` crate.
  14 nsresult NS_NewAppServicesLogger(mozIAppServicesLogger** aResult);
  15
  16 }  // extern "C"
  17
  18 namespace mozilla {
  19 namespace appservices {
  20
  21 // The C++ constructor for a `services.appServicesLogger` service. This wrapper
  22 // exists because `components.conf` requires a component class constructor to
  23 // return an `already_AddRefed<T>`, but Rust doesn't have such a type. So we
  24 // call the Rust constructor using a `nsCOMPtr` (which is compatible with Rust's
  25 // `xpcom::RefPtr`) out param, and return that.
  26 already_AddRefed<mozIAppServicesLogger> NewLogService() {
  27   nsCOMPtr<mozIAppServicesLogger> logger;
  28   nsresult rv = NS_NewAppServicesLogger(getter_AddRefs(logger));
  29   if (NS_WARN_IF(NS_FAILED(rv))) {
  30     return nullptr;
  31   }
  32   return logger.forget();
  33 }
  34
  35 }  // namespace appservices
  36 }  // namespace mozilla
  37
  38 #endif  // mozilla_services_AppServicesLoggerComponents_h_