Introduce an internal QtJniTypes namespace with types that allow us to
concatenate string literals at compile time. This makes it possible to
generate arbitrary strings based on types, which we can then use as
signatures to JNI method calls.
Move some of the private members of QJniObject into the QtJniTypes
namespace for consistency, and to allow further template specialization
by user code to make other types and their JNI signature string known.
Remove the "Jni" prefix from names.
Use the compile-time generated string in QJniObject methods that created
the signature string at runtime, which involved a temporary memory
allocation.
Treat 'void' as a primitive type (with signature string 'V'), and
remove redundant template specializations.
Add a test case to verify the the strings are constructed correctly
at compile time.
Change-Id: I5e3895a97f7dc1b86961f7a7855b899d9203037d
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>