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exception-safe object creation, fixes #118

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This commit is contained in:
Daniel Frey 2015-09-20 20:06:33 +02:00
parent 0a81353989
commit f7fb405564
1 changed files with 25 additions and 42 deletions
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67
src/json.hpp.re2c
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@ -584,6 +584,17 @@ class basic_json
private:
/// helper for exception-safe object creation
template<typename T, typename... Args>
static T* create( Args&&... args )
{
AllocatorType<T> alloc;
auto deleter = [&](T* object) { alloc.deallocate(object, 1); };
std::unique_ptr<T, decltype(deleter)> object(alloc.allocate(1), deleter);
alloc.construct(object.get(), std::forward<Args>(args)...);
return object.release();
}
////////////////////////
// JSON value storage //
////////////////////////
@ -625,25 +636,19 @@ class basic_json
case (value_t::object):
{
AllocatorType<object_t> alloc;
object = alloc.allocate(1);
alloc.construct(object);
object = create<object_t>();
break;
}
case (value_t::array):
{
AllocatorType<array_t> alloc;
array = alloc.allocate(1);
alloc.construct(array);
array = create<array_t>();
break;
}
case (value_t::string):
{
AllocatorType<string_t> alloc;
string = alloc.allocate(1);
alloc.construct(string, "");
string = create<string_t>("");
break;
}
@ -670,25 +675,19 @@ class basic_json
/// constructor for strings
json_value(const string_t& value)
{
AllocatorType<string_t> alloc;
string = alloc.allocate(1);
alloc.construct(string, value);
string = create<string_t>(value);
}
/// constructor for objects
json_value(const object_t& value)
{
AllocatorType<object_t> alloc;
object = alloc.allocate(1);
alloc.construct(object, value);
object = create<object_t>(value);
}
/// constructor for arrays
json_value(const array_t& value)
{
AllocatorType<array_t> alloc;
array = alloc.allocate(1);
alloc.construct(array, value);
array = create<array_t>(value);
}
};
@ -892,11 +891,9 @@ class basic_json
basic_json(const CompatibleObjectType& value)
: m_type(value_t::object)
{
AllocatorType<object_t> alloc;
m_value.object = alloc.allocate(1);
using std::begin;
using std::end;
alloc.construct(m_value.object, begin(value), end(value));
m_value.object = create<object_t>(begin(value), end(value));
}
/*!
@ -953,11 +950,9 @@ class basic_json
basic_json(const CompatibleArrayType& value)
: m_type(value_t::array)
{
AllocatorType<array_t> alloc;
m_value.array = alloc.allocate(1);
using std::begin;
using std::end;
alloc.construct(m_value.array, begin(value), end(value));
m_value.array = create<array_t>(begin(value), end(value));
}
/*!
@ -1315,9 +1310,7 @@ class basic_json
{
// the initializer list describes an array -> create array
m_type = value_t::array;
AllocatorType<array_t> alloc;
m_value.array = alloc.allocate(1);
alloc.construct(m_value.array, std::move(init));
m_value.array = create<array_t>(std::move(init));
}
}
@ -1416,9 +1409,7 @@ class basic_json
basic_json(size_type count, const basic_json& value)
: m_type(value_t::array)
{
AllocatorType<array_t> alloc;
m_value.array = alloc.allocate(1);
alloc.construct(m_value.array, count, value);
m_value.array = create<array_t>(count, value);
}
/*!
@ -1514,17 +1505,13 @@ class basic_json
case value_t::object:
{
AllocatorType<object_t> alloc;
m_value.object = alloc.allocate(1);
alloc.construct(m_value.object, first.m_it.object_iterator, last.m_it.object_iterator);
m_value.object = create<object_t>(first.m_it.object_iterator, last.m_it.object_iterator);
break;
}
case value_t::array:
{
AllocatorType<array_t> alloc;
m_value.array = alloc.allocate(1);
alloc.construct(m_value.array, first.m_it.array_iterator, last.m_it.array_iterator);
m_value.array = create<array_t>(first.m_it.array_iterator, last.m_it.array_iterator);
break;
}
@ -2598,9 +2585,7 @@ class basic_json
if (m_type == value_t::null)
{
m_type = value_t::array;
AllocatorType<array_t> alloc;
m_value.array = alloc.allocate(1);
alloc.construct(m_value.array);
m_value.array = create<array_t>();
}
// [] only works for arrays
@ -2670,9 +2655,7 @@ class basic_json
if (m_type == value_t::null)
{
m_type = value_t::object;
AllocatorType<object_t> alloc;
m_value.object = alloc.allocate(1);
alloc.construct(m_value.object);
m_value.object = create<object_t>();
}
// [] only works for objects