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Merge pull request #609 from theodelrieu/develop

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Add pair support, fix CompatibleObject conversions (fixes #600)
This commit is contained in:
Niels Lohmann 2017-06-07 16:38:23 +02:00 committed by GitHub
commit 52f934cbbf
2 changed files with 96 additions and 4 deletions
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52
src/json.hpp
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@ -285,7 +285,7 @@ class invalid_iterator : public exception
Exceptions have ids 3xx.
name / id | example massage | description
name / id | example message | description
----------------------------- | --------------- | -------------------------
json.exception.type_error.301 | cannot create object from initializer list | To create an object from an initializer list, the initializer list must consist only of a list of pairs whose first element is a string. When this constraint is violated, an array is created instead.
json.exception.type_error.302 | type must be object, but is array | During implicit or explicit value conversion, the JSON type must be compatible to the target type. For instance, a JSON string can only be converted into string types, but not into numbers or boolean types.
@ -324,7 +324,7 @@ class type_error : public exception
Exceptions have ids 4xx.
name / id | example massage | description
name / id | example message | description
------------------------------- | --------------- | -------------------------
json.exception.out_of_range.401 | array index 3 is out of range | The provided array index @a i is larger than @a size-1.
json.exception.out_of_range.402 | array index '-' (3) is out of range | The special array index `-` in a JSON Pointer never describes a valid element of the array, but the index past the end. That is, it can only be used to add elements at this position, but not to read it.
@ -355,9 +355,10 @@ class out_of_range : public exception
Exceptions have ids 5xx.
name / id | example massage | description
name / id | example message | description
------------------------------ | --------------- | -------------------------
json.exception.other_error.501 | unsuccessful: {"op":"test","path":"/baz", "value":"bar"} | A JSON Patch operation 'test' failed. The unsuccessful operation is also printed.
json.exception.other_error.502 | invalid object size for conversion | Some conversions to user-defined types impose constraints on the object size (e.g. std::pair)
@since version 3.0.0
*/
@ -865,6 +866,14 @@ void to_json(BasicJsonType& j, T (&arr)[N])
external_constructor<value_t::array>::construct(j, arr);
}
template <typename BasicJsonType, typename CompatibleString, typename T,
enable_if_t<std::is_constructible<typename BasicJsonType::string_t,
CompatibleString>::value, int> = 0>
void to_json(BasicJsonType& j, std::pair<CompatibleString, T> const& p)
{
j[p.first] = p.second;
}
///////////////
// from_json //
///////////////
@ -1037,10 +1046,24 @@ void from_json(const BasicJsonType& j, CompatibleObjectType& obj)
auto inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
using std::begin;
using std::end;
using value_type = typename CompatibleObjectType::value_type;
std::vector<value_type> v;
v.reserve(j.size());
std::transform(
inner_object->begin(), inner_object->end(), std::back_inserter(v),
[](typename BasicJsonType::object_t::value_type const & p)
{
return value_type
{
p.first,
p.second
.template get<typename CompatibleObjectType::mapped_type>()};
});
// we could avoid the assignment, but this might require a for loop, which
// might be less efficient than the container constructor for some
// containers (would it?)
obj = CompatibleObjectType(begin(*inner_object), end(*inner_object));
obj = CompatibleObjectType(std::make_move_iterator(begin(v)),
std::make_move_iterator(end(v)));
}
// overload for arithmetic types, not chosen for basic_json template arguments
@ -1086,6 +1109,27 @@ void from_json(const BasicJsonType& j, ArithmeticType& val)
}
}
template <typename BasicJsonType, typename CompatibleString, typename T,
enable_if_t<std::is_constructible<typename BasicJsonType::string_t,
CompatibleString>::value, int> = 0>
void from_json(const BasicJsonType& j, std::pair<CompatibleString, T>& p)
{
if (not j.is_object())
{
JSON_THROW(type_error::create(302, "type must be object, but is " + j.type_name()));
}
auto const inner_object = j.template get_ptr<const typename BasicJsonType::object_t*>();
auto const size = inner_object->size();
if (size != 1)
{
JSON_THROW(other_error::create(502, "conversion to std::pair requires the object to have exactly one field, but it has " + std::to_string(size)));
}
auto const& obj = *inner_object->begin();
// cannot use *inner_object, need to convert both members
p = std::make_pair(obj.first, obj.second.template get<T>());
}
struct to_json_fn
{
private:

48
test/src/unit-constructor1.cpp
View File

@ -156,6 +156,31 @@ TEST_CASE("constructors")
CHECK(j == j_reference);
}
SECTION("std::pair<CompatibleString, T>")
{
std::pair<std::string, std::string> p{"first", "second"};
json j(p);
CHECK((j.get<decltype(p)>() == p));
std::pair<std::string, int> p2{"first", 1};
// use char const*
json j2(std::make_pair("first", 1));
CHECK((j2.get<decltype(p2)>() == p2));
}
SECTION("std::map<std::string, std::string> #600")
{
std::map<std::string, std::string> m;
m["a"] = "b";
m["c"] = "d";
m["e"] = "f";
json j(m);
CHECK((j.get<decltype(m)>() == m));
}
SECTION("std::map<const char*, json>")
{
std::map<const char*, json> o {{"a", json(1)}, {"b", json(1u)}, {"c", json(2.2)}, {"d", json(false)}, {"e", json("string")}, {"f", json()}};
@ -164,6 +189,7 @@ TEST_CASE("constructors")
CHECK(j == j_reference);
}
SECTION("std::multimap<json::string_t, json>")
{
std::multimap<json::string_t, json> o {{"a", json(1)}, {"b", json(1u)}, {"c", json(2.2)}, {"d", json(false)}, {"e", json("string")}, {"f", json()}};
@ -954,6 +980,28 @@ TEST_CASE("constructors")
"[json.exception.type_error.301] cannot create object from initializer list");
}
SECTION("std::pair<CompatibleString, T> with error")
{
SECTION("wrong field number")
{
json j{{"too", "much"}, {"string", "fields"}};
CHECK_THROWS_AS((j.get<std::pair<std::string, std::string>>()), json::other_error);
CHECK_THROWS_WITH((j.get<std::pair<std::string, std::string>>()),
"[json.exception.other_error.502] conversion "
"to std::pair requires the object to have "
"exactly one field, but it has 2");
}
SECTION("wrong JSON type")
{
json j(42);
CHECK_THROWS_AS((j.get<std::pair<std::string, std::string>>()), json::type_error);
CHECK_THROWS_WITH((j.get<std::pair<std::string, std::string>>()),
"[json.exception.type_error.302] type must be object, but is number");
}
}
SECTION("empty array")
{
json j = json::array();