Unique_ptr c++ usage - c++

Question

Sincerelly i m not so expert with c++ RAII features. I never used before. Anyway i m begining to study about it (i m in "kernel panic"). Compiling a module i have the following error :
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h: In instantiation of ‘void std::unique_ptr<_Tp [], _Dp>::reset(_Up) [with _Up = char*; <template-parameter-2-2> = void; _Tp = const char; _Dp = std::default_delete<const char []>]’:
/usr/include/c++/6/bits/unique_ptr.h:539:9: required from ‘typename std::enable_if<std::__and_<std::__and_<std::is_array<_Up>, std::is_same<typename std::unique_ptr<_Tp [], _Dp>::_Pointer::type, _Tp*>, std::is_same<typename std::unique_ptr<_Up, _Ep>::pointer, typename std::unique_ptr<_Up, _Ep>::element_type*>, std::is_convertible<typename std::unique_ptr<_Up, _Ep>::element_type (*)[], _Tp (*)[]>, std::__or_<std::__and_<std::is_reference<_Dp>, std::is_same<_T2, _U2> >, std::__and_<std::__not_<std::is_reference<_Dp> >, std::is_convertible<_Ep, _Dp> > > >, std::is_assignable<_T2&, _U2&&> >::value, std::unique_ptr<_Tp [], _Dp>&>::type std::unique_ptr<_Tp [], _Dp>::operator=(std::unique_ptr<_Up, _Ep>&&) [with _Up = char []; _Ep = std::default_delete<char []>; _Tp = const char; _Dp = std::default_delete<const char []>; typename std::enable_if<std::__and_<std::__and_<std::is_array<_Up>, std::is_same<typename std::unique_ptr<_Tp [], _Dp>::_Pointer::type, _Tp*>, std::is_same<typename std::unique_ptr<_Up, _Ep>::pointer, typename std::unique_ptr<_Up, _Ep>::element_type*>, std::is_convertible<typename std::unique_ptr<_Up, _Ep>::element_type (*)[], _Tp (*)[]>, std::__or_<std::__and_<std::is_reference<_Dp>, std::is_same<_T2, _U2> >, std::__and_<std::__not_<std::is_reference<_Dp> >, std::is_convertible<_Ep, _Dp> > > >, std::is_assignable<_T2&, _U2&&> >::value, std::unique_ptr<_Tp [], _Dp>&>::type = std::unique_ptr<const char []>&]’
java/rocksjni/compaction_filter_factory_jnicallback.cc:33:58: required from here
/usr/include/c++/6/bits/unique_ptr.h:614:6: error: no matching function for call to ‘swap(const char*&, char*&)’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/bits/stl_pair.h:59:0,
from /usr/include/c++/6/bits/stl_algobase.h:64,
from /usr/include/c++/6/memory:62,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/move.h:179:5: note: candidate: template<class _Tp> typename std::enable_if<std::__and_<std::is_move_constructible<_Tp>, std::is_move_assignable<_Tp> >::value>::type std::swap(_Tp&, _Tp&)
swap(_Tp& __a, _Tp& __b)
^~~~
/usr/include/c++/6/bits/move.h:179:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: deduced conflicting types for parameter ‘_Tp’ (‘const char*’ and ‘char*’)
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/bits/stl_pair.h:59:0,
from /usr/include/c++/6/bits/stl_algobase.h:64,
from /usr/include/c++/6/memory:62,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/move.h:202:5: note: candidate: template<class _Tp, long unsigned int _Nm> typename std::enable_if<std::__is_swappable<_Tp>::value>::type std::swap(_Tp (&)[_Nm], _Tp (&)[_Nm])
swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
^~~~
/usr/include/c++/6/bits/move.h:202:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘_Tp [_Nm]’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:64:0,
from /usr/include/c++/6/memory:62,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/stl_pair.h:471:5: note: candidate: template<class _T1, class _T2> void std::swap(std::pair<_T1, _T2>&, std::pair<_T1, _T2>&)
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
^~~~
/usr/include/c++/6/bits/stl_pair.h:471:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::pair<_T1, _T2>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
from /usr/include/c++/6/stdexcept:39,
from /usr/include/c++/6/array:39,
from /usr/include/c++/6/tuple:39,
from /usr/include/c++/6/functional:55,
from /usr/include/c++/6/memory:79,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/basic_string.h:5287:5: note: candidate: template<class _CharT, class _Traits, class _Alloc> void std::swap(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)
swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
^~~~
/usr/include/c++/6/bits/basic_string.h:5287:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/tuple:39:0,
from /usr/include/c++/6/functional:55,
from /usr/include/c++/6/memory:79,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/array:275:5: note: candidate: template<class _Tp, long unsigned int _Nm> void std::swap(std::array<_Tp, _Nm>&, std::array<_Tp, _Nm>&)
swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
^~~~
/usr/include/c++/6/array:275:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::array<_Tp, _Nm>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/functional:55:0,
from /usr/include/c++/6/memory:79,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/tuple:1546:5: note: candidate: template<class ... _Elements> void std::swap(std::tuple<_Elements ...>&, std::tuple<_Elements ...>&)
swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
^~~~
/usr/include/c++/6/tuple:1546:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::tuple<_Elements ...>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/memory:79:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/functional:2238:5: note: candidate: template<class _Res, class ... _Args> void std::swap(std::function<_Res(_ArgTypes ...)>&, std::function<_Res(_ArgTypes ...)>&)
swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
^~~~
/usr/include/c++/6/functional:2238:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/compaction_filter_factory_jnicallback.h:13,
from java/rocksjni/compaction_filter_factory_jnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::function<_Res(_ArgTypes ...)>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h: In instantiation of ‘void std::unique_ptr<_Tp [], _Dp>::reset(_Up) [with _Up = char*; <template-parameter-2-2> = void; _Tp = const char; _Dp = std::default_delete<const char []>]’:
/usr/include/c++/6/bits/unique_ptr.h:539:9: required from ‘typename std::enable_if<std::__and_<std::__and_<std::is_array<_Up>, std::is_same<typename std::unique_ptr<_Tp [], _Dp>::_Pointer::type, _Tp*>, std::is_same<typename std::unique_ptr<_Up, _Ep>::pointer, typename std::unique_ptr<_Up, _Ep>::element_type*>, std::is_convertible<typename std::unique_ptr<_Up, _Ep>::element_type (*)[], _Tp (*)[]>, std::__or_<std::__and_<std::is_reference<_Dp>, std::is_same<_T2, _U2> >, std::__and_<std::__not_<std::is_reference<_Dp> >, std::is_convertible<_Ep, _Dp> > > >, std::is_assignable<_T2&, _U2&&> >::value, std::unique_ptr<_Tp [], _Dp>&>::type std::unique_ptr<_Tp [], _Dp>::operator=(std::unique_ptr<_Up, _Ep>&&) [with _Up = char []; _Ep = std::default_delete<char []>; _Tp = const char; _Dp = std::default_delete<const char []>; typename std::enable_if<std::__and_<std::__and_<std::is_array<_Up>, std::is_same<typename std::unique_ptr<_Tp [], _Dp>::_Pointer::type, _Tp*>, std::is_same<typename std::unique_ptr<_Up, _Ep>::pointer, typename std::unique_ptr<_Up, _Ep>::element_type*>, std::is_convertible<typename std::unique_ptr<_Up, _Ep>::element_type (*)[], _Tp (*)[]>, std::__or_<std::__and_<std::is_reference<_Dp>, std::is_same<_T2, _U2> >, std::__and_<std::__not_<std::is_reference<_Dp> >, std::is_convertible<_Ep, _Dp> > > >, std::is_assignable<_T2&, _U2&&> >::value, std::unique_ptr<_Tp [], _Dp>&>::type = std::unique_ptr<const char []>&]’
java/rocksjni/comparatorjnicallback.cc:34:21: required from here
/usr/include/c++/6/bits/unique_ptr.h:614:6: error: no matching function for call to ‘swap(const char*&, char*&)’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/bits/stl_pair.h:59:0,
from /usr/include/c++/6/bits/stl_algobase.h:64,
from /usr/include/c++/6/memory:62,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/move.h:179:5: note: candidate: template<class _Tp> typename std::enable_if<std::__and_<std::is_move_constructible<_Tp>, std::is_move_assignable<_Tp> >::value>::type std::swap(_Tp&, _Tp&)
swap(_Tp& __a, _Tp& __b)
^~~~
/usr/include/c++/6/bits/move.h:179:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: deduced conflicting types for parameter ‘_Tp’ (‘const char*’ and ‘char*’)
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/bits/stl_pair.h:59:0,
from /usr/include/c++/6/bits/stl_algobase.h:64,
from /usr/include/c++/6/memory:62,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/move.h:202:5: note: candidate: template<class _Tp, long unsigned int _Nm> typename std::enable_if<std::__is_swappable<_Tp>::value>::type std::swap(_Tp (&)[_Nm], _Tp (&)[_Nm])
swap(_Tp (&__a)[_Nm], _Tp (&__b)[_Nm])
^~~~
/usr/include/c++/6/bits/move.h:202:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘_Tp [_Nm]’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/bits/stl_algobase.h:64:0,
from /usr/include/c++/6/memory:62,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/stl_pair.h:471:5: note: candidate: template<class _T1, class _T2> void std::swap(std::pair<_T1, _T2>&, std::pair<_T1, _T2>&)
swap(pair<_T1, _T2>& __x, pair<_T1, _T2>& __y)
^~~~
/usr/include/c++/6/bits/stl_pair.h:471:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::pair<_T1, _T2>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/string:52:0,
from /usr/include/c++/6/stdexcept:39,
from /usr/include/c++/6/array:39,
from /usr/include/c++/6/tuple:39,
from /usr/include/c++/6/functional:55,
from /usr/include/c++/6/memory:79,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/basic_string.h:5287:5: note: candidate: template<class _CharT, class _Traits, class _Alloc> void std::swap(std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&, std::__cxx11::basic_string<_CharT, _Traits, _Alloc>&)
swap(basic_string<_CharT, _Traits, _Alloc>& __lhs,
^~~~
/usr/include/c++/6/bits/basic_string.h:5287:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::__cxx11::basic_string<_CharT, _Traits, _Alloc>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/tuple:39:0,
from /usr/include/c++/6/functional:55,
from /usr/include/c++/6/memory:79,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/array:275:5: note: candidate: template<class _Tp, long unsigned int _Nm> void std::swap(std::array<_Tp, _Nm>&, std::array<_Tp, _Nm>&)
swap(array<_Tp, _Nm>& __one, array<_Tp, _Nm>& __two)
^~~~
/usr/include/c++/6/array:275:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::array<_Tp, _Nm>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/functional:55:0,
from /usr/include/c++/6/memory:79,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/tuple:1546:5: note: candidate: template<class ... _Elements> void std::swap(std::tuple<_Elements ...>&, std::tuple<_Elements ...>&)
swap(tuple<_Elements...>& __x, tuple<_Elements...>& __y)
^~~~
/usr/include/c++/6/tuple:1546:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::tuple<_Elements ...>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/6/memory:79:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/functional:2238:5: note: candidate: template<class _Res, class ... _Args> void std::swap(std::function<_Res(_ArgTypes ...)>&, std::function<_Res(_ArgTypes ...)>&)
swap(function<_Res(_Args...)>& __x, function<_Res(_Args...)>& __y)
^~~~
/usr/include/c++/6/functional:2238:5: note: template argument deduction/substitution failed:
In file included from /usr/include/c++/6/memory:81:0,
from ./java/./rocksjni/comparatorjnicallback.h:13,
from java/rocksjni/comparatorjnicallback.cc:9:
/usr/include/c++/6/bits/unique_ptr.h:614:6: note: mismatched types ‘std::function<_Res(_ArgTypes ...)>’ and ‘std::__tuple_element_t<0ul, std::tuple<const char*, std::default_delete<const char []> > > {aka const char*}’
swap(std::get<0>(_M_t), __p);
I m not sure to understand this stack trace but it seams there is a mismatch in the unique_ptr . Maybe const char* and char*.
the class where there is the bug is :
CompactionFilterFactoryJniCallback::CompactionFilterFactoryJniCallback(
JNIEnv* env, jobject jcompaction_filter_factory)
: JniCallback(env, jcompaction_filter_factory) {
// Note: The name of a CompactionFilterFactory will not change during
// it's lifetime, so we cache it in a global var
jmethodID jname_method_id =
AbstractCompactionFilterFactoryJni::getNameMethodId(env);
if(jname_method_id == nullptr) {
// exception thrown: NoSuchMethodException or OutOfMemoryError
return;
}
jstring jname =
(jstring)env->CallObjectMethod(m_jcallback_obj, jname_method_id);
if(env->ExceptionCheck()) {
// exception thrown
return;
}
jboolean has_exception = JNI_FALSE;
// line 33
m_name = JniUtil::copyString(env, jname, &has_exception); // also releases jname
if (has_exception == JNI_TRUE) {
// exception thrown
return;
}
m_jcreate_compaction_filter_methodid =
AbstractCompactionFilterFactoryJni::getCreateCompactionFilterMethodId(env);
if(m_jcreate_compaction_filter_methodid == nullptr) {
// exception thrown: NoSuchMethodException or OutOfMemoryError
return;
}
}
const char* CompactionFilterFactoryJniCallback::Name() const {
return m_name.get();
}
std::unique_ptr<CompactionFilter> CompactionFilterFactoryJniCallback::CreateCompactionFilter(
const CompactionFilter::Context& context) {
jboolean attached_thread = JNI_FALSE;
JNIEnv* env = getJniEnv(&attached_thread);
assert(env != nullptr);
jlong addr_compaction_filter = env->CallLongMethod(m_jcallback_obj,
m_jcreate_compaction_filter_methodid,
static_cast<jboolean>(context.is_full_compaction),
static_cast<jboolean>(context.is_manual_compaction));
if(env->ExceptionCheck()) {
// exception thrown from CallLongMethod
env->ExceptionDescribe(); // print out exception to stderr
releaseJniEnv(attached_thread);
return nullptr;
}
auto* const cff = reinterpret_cast<CompactionFilter*>(addr_compaction_filter);
releaseJniEnv(attached_thread);
return std::unique_ptr<CompactionFilter>(cff);
}
It is not clear how to read this stack trace for identifying the problem. I would appreciate to receive a little suggestion for understand how fix the problem and read the stack trace.

Answer 1

The error says that you have a std::unique_ptr<char const[]> object on which you try to call function reset passing char* as an argument.
Well, that argument needs to be char const* for that to compile, which you can achieve with a const_cast, e.g.:
std::unique_ptr<char const[]> p;
char* q = new char[1]{};
p.reset(const_cast<char const*>(q));
Looks like JniUtil::copyString returns std::unique_ptr<char[]> and you assign it to std::unique_ptr<char const[]> which causes the error.
One fix is to change the type of m_name to be std::unique_ptr<char[]>.
Another is to manually add constness (adding constness is safe and is an implicit conversion, but is needed here to choose the correct overload of std::unique_ptr<>::reset):
m_name.reset(const_cast<char const*>(JniUtil::copyString(...).release()));