2017-12-27 580 views
-3

因爲我不太熟悉C++ RAII特性。我從來沒有用過。無論如何,我開始研究它(我在「內核恐慌」)。編譯模塊,我有以下錯誤:Unique_ptr C++用法

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); 

我不是一定要了解該堆棧跟蹤,但它接縫有在的unique_ptr不匹配。也許const char *和char *。

類哪裏有錯誤是:

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); 
} 

目前尚不清楚如何閱讀堆棧跟蹤識別問題。我希望收到一些建議,瞭解如何解決問題並閱讀堆棧跟蹤。

+2

哪條線是線33?什麼是'm_name'的類型? – cpplearner

+0

「CompactionFilter」類的定義是什麼?如果你沒有使用'unique_ptr',並且你完成了使用這種方式創建的'CompactionFilter',你將如何擺脫它? –

+0

請將代碼縮小到[mcve]。 –

回答

0

錯誤說你有,你嘗試調用函數reset傳遞char*作爲參數std::unique_ptr<char const[]>對象。

好了,這樣的說法必須char const*爲編譯,您可以用const_cast實現,如:

std::unique_ptr<char const[]> p; 
char* q = new char[1]{}; 
p.reset(const_cast<char const*>(q)); 

貌似JniUtil::copyString回報std::unique_ptr<char[]>,你把它分配給std::unique_ptr<char const[]>導致錯誤。

一種修復方法是將m_name的類型更改爲std::unique_ptr<char[]>

另一種是手動添加常量性(增加常量性是安全的,是一個隱式轉換,但這裏需要選擇的std::unique_ptr<>::reset正確的過載):

m_name.reset(const_cast<char const*>(JniUtil::copyString(...).release())); 
+0

'const_cast'非常非常*很少是正確的解決方案。 –

+0

@JesperJuhl如果你在這裏考慮'const_cast',它會添加const而不是刪除它,這是非常安全的,並且是一種隱式轉換。 –

+0

m_name.reset(const_cast (JniUtil :: copyString(env,jname,&has_exception))); //也釋放jname ---> java/rocksjni/compaction_filter_factory_jnicallback.cc:34:90:error:從類型'std :: unique_ptr '無效const_cast類型'char * const' m_name.reset(const_cast (JniUtil :: copyString(env,jname,&has_exception))); //也發佈jname –