Add ImplPtr and makeImpl

The original (more complex and comprehensive) solution belongs to
https://oliora.github.io/2015/12/29/pimpl-and-rule-of-zero.html - this
commit only provides a small wrapper for non-copyable Private class
implementations common throughout libQuotient. Unlike the original,
default initialisation is made explicit - you have to pass
ZeroImpl<Private>() instead (and I firmly believe it's a good thing:
normally pointers to Private should not remain nullptr). The reason
ZeroImpl<> is not a template variable is quite simple: unique_ptr is
non-copyable and so cannot be initialised from; while a template
function will initialise the value in-place thanks to copy elision.

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/jobs/basejob.h b/lib/jobs/basejob.h
index f41fc63c..c899170d 100644
--- a/lib/jobs/basejob.h
+++ b/lib/jobs/basejob.h
@@ -467,7 +467,7 @@ private:
     void finishJob();
 
     class Private;
-    QScopedPointer<Private> d;
+    ImplPtr<Private> d;
 };
 
 inline bool QUOTIENT_API isJobPending(BaseJob* job)