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mdbx++: refine buffer::data_preserver.

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Change-Id: Ie101209588daa10bb5ad21ece0f3ea469e9b98e6
This commit is contained in:
Leonid Yuriev 2020-09-26 01:40:11 +03:00
parent 9f071c7dbe
commit c424a80705
1 changed files with 20 additions and 16 deletions
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36
mdbx.h++
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@ -854,11 +854,17 @@ template <class ALLOCATOR = legacy_allocator> class buffer {
} }
struct data_preserver : public exception_thunk { struct data_preserver : public exception_thunk {
buffer data;
data_preserver(ALLOCATOR &allocator) : data(allocator) {}
static int callback(void *context, MDBX_val *target, const void *src, static int callback(void *context, MDBX_val *target, const void *src,
size_t bytes) noexcept; size_t bytes) noexcept;
MDBX_CXX11_CONSTEXPR operator MDBX_preserve_func() const noexcept { MDBX_CXX11_CONSTEXPR operator MDBX_preserve_func() const noexcept {
return callback; return callback;
} }
MDBX_CXX11_CONSTEXPR operator const buffer &() const noexcept {
return data;
}
MDBX_CXX11_CONSTEXPR operator buffer &() noexcept { return data; }
}; };
public: public:
@ -3964,12 +3970,11 @@ inline void txn::replace(map_handle map, const slice &key, slice old_value,
template <class ALLOCATOR> template <class ALLOCATOR>
inline buffer<ALLOCATOR> txn::extract(map_handle map, const slice &key, inline buffer<ALLOCATOR> txn::extract(map_handle map, const slice &key,
const ALLOCATOR &allocator) { const ALLOCATOR &allocator) {
buffer<ALLOCATOR> result(allocator); typename buffer<ALLOCATOR>::data_preserver result(allocator);
typename buffer<ALLOCATOR>::data_preserver thunk;
error::success_or_throw(::mdbx_replace_ex(handle_, map.dbi, &key, nullptr, error::success_or_throw(::mdbx_replace_ex(handle_, map.dbi, &key, nullptr,
&result.slice_, MDBX_CURRENT, thunk, &result.slice_, MDBX_CURRENT,
&thunk), result, &result),
thunk); result);
return result; return result;
} }
@ -3977,12 +3982,11 @@ template <class ALLOCATOR>
inline buffer<ALLOCATOR> txn::replace(map_handle map, const slice &key, inline buffer<ALLOCATOR> txn::replace(map_handle map, const slice &key,
const slice &new_value, const slice &new_value,
const ALLOCATOR &allocator) { const ALLOCATOR &allocator) {
buffer<ALLOCATOR> result(allocator); typename buffer<ALLOCATOR>::data_preserver result(allocator);
typename buffer<ALLOCATOR>::data_preserver thunk;
error::success_or_throw( error::success_or_throw(
::mdbx_replace_ex(handle_, map.dbi, &key, const_cast<slice *>(&new_value), ::mdbx_replace_ex(handle_, map.dbi, &key, const_cast<slice *>(&new_value),
&result.slice_, MDBX_CURRENT, thunk, &thunk), &result.slice_, MDBX_CURRENT, result, &result),
thunk); result);
return result; return result;
} }
@ -3990,12 +3994,11 @@ template <class ALLOCATOR>
inline buffer<ALLOCATOR> txn::replace_reserve(map_handle map, const slice &key, inline buffer<ALLOCATOR> txn::replace_reserve(map_handle map, const slice &key,
slice &new_value, slice &new_value,
const ALLOCATOR &allocator) { const ALLOCATOR &allocator) {
buffer<ALLOCATOR> result(allocator); typename buffer<ALLOCATOR>::data_preserver result(allocator);
typename buffer<ALLOCATOR>::data_preserver thunk;
error::success_or_throw( error::success_or_throw(
::mdbx_replace_ex(handle_, map.dbi, &key, &new_value, &result.slice_, ::mdbx_replace_ex(handle_, map.dbi, &key, &new_value, &result.slice_,
MDBX_CURRENT | MDBX_RESERVE, thunk, &thunk), MDBX_CURRENT | MDBX_RESERVE, result, &result),
thunk); result);
return result; return result;
} }
@ -4549,11 +4552,12 @@ inline int buffer<ALLOCATOR>::data_preserver::callback(void *context,
MDBX_val *target, MDBX_val *target,
const void *src, const void *src,
size_t bytes) noexcept { size_t bytes) noexcept {
const auto self = static_cast<data_preserver *>(context); auto self = static_cast<data_preserver *>(context);
assert(self->is_clean()); assert(self->is_clean());
assert(&self->data.slice_ == target);
(void)target;
try { try {
owner_of(static_cast<::mdbx::slice *>(target), &buffer::slice_) self->data.assign(src, bytes, false);
->assign(src, bytes, false);
return MDBX_RESULT_FALSE; return MDBX_RESULT_FALSE;
} catch (... /* capture any exception to rethrow it over C code */) { } catch (... /* capture any exception to rethrow it over C code */) {
self->capture(); self->capture();