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4
Commits
| Author | SHA1 | Date | |
|---|---|---|---|
 Niels Lohmann
|
8e4842cbf7 | ||
|
Niels Lohmann
|
f386f367df | ||
|
Niels Lohmann
|
abf827a5bd | ||
|
Niels Lohmann
|
a335a81ba7 |
@@ -562,7 +562,11 @@ binary32 or binary64 field and have no encoding for `#!cpp long double`.
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## `AllocatorType`
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`AllocatorType` is instantiated with **one** argument, for each of `object_t`, `array_t`, `string_t`, `binary_t`,
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`basic_json`, and `#!cpp std::pair<const StringType, basic_json>`.
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`basic_json`, `#!cpp std::pair<const StringType, basic_json>`, and `#!cpp std::pair<StringType, basic_json>`.
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`AllocatorType` is not the only allocator a `basic_json` uses. It allocates the JSON values themselves, but most
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temporary storage is allocated with `#!cpp std::allocator`. This includes the parser's stacks and the stacks that
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process deeply nested values without recursion.
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### Always required
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+4
-400
@@ -1003,7 +1003,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
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using copy_worklist_t = std::vector<std::pair<const basic_json*, basic_json*>>;
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/// scratch space to build the key skeleton of an object copy in one go
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using copy_scratch_t = std::vector<std::pair<typename object_t::key_type, basic_json>>;
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using copy_scratch_value_t = std::pair<typename object_t::key_type, basic_json>;
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using copy_scratch_t = std::vector<copy_scratch_value_t, AllocatorType<copy_scratch_value_t>>;
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/// @brief copy everything of @a src into @a dst but its type and value
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static void copy_metadata(const basic_json& src, basic_json& dst)
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@@ -5992,100 +5993,6 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
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JSON_HEDLEY_WARN_UNUSED_RESULT
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static basic_json diff(const basic_json& source, const basic_json& target,
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const string_t& path = "")
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{
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// Diffing descends into both values once per nesting level and
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// compares them with operator== on the way, which recurses as well,
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// so values nested deeply enough used to exhaust the call stack.
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// Both only descend as far as the source is nested, so a source
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// nested no more than detail::recursion_depth_limit() levels deep -
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// all but a vanishing minority - is diffed recursively as before;
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// deeper ones are diffed without the call stack.
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if (JSON_HEDLEY_LIKELY(!nesting_exceeds(source, detail::recursion_depth_limit())))
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{
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return diff_recursively(source, target, path);
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}
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return diff_iteratively(source, target, path);
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}
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private:
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/*!
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@brief whether @a j is nested more than @a limit levels deep
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A primitive value is not nested at all, an array or object one level more
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than its most deeply nested element. Recurses at most @a limit levels.
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*/
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static bool nesting_exceeds(const basic_json& j, const std::size_t limit)
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{
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switch (j.m_data.m_type)
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{
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case value_t::array:
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{
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return limit == 0 || std::any_of(j.m_data.m_value.array->cbegin(), j.m_data.m_value.array->cend(),
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[limit](const basic_json & element)
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{
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return element.is_structured() && nesting_exceeds(element, limit - 1);
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});
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}
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||||
|
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case value_t::object:
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{
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return limit == 0 || std::any_of(j.m_data.m_value.object->cbegin(), j.m_data.m_value.object->cend(),
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[limit](const typename object_t::value_type & element)
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{
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return element.second.is_structured() && nesting_exceeds(element.second, limit - 1);
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});
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}
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|
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case value_t::null:
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case value_t::string:
|
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case value_t::boolean:
|
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case value_t::number_integer:
|
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case value_t::number_unsigned:
|
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case value_t::number_float:
|
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case value_t::binary:
|
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case value_t::discarded:
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default:
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return false;
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}
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}
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/// @brief two arrays or two objects @ref diff_iteratively is diffing
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struct diff_frame
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{
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diff_frame(const basic_json* source_, const basic_json* target_, const std::size_t path_length_) noexcept
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: source(source_), target(target_), path_length(path_length_)
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{}
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// declared for GCC's -Weffc++, which asks for them in a class with
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// pointer members and a non-trivial destructor; the exception
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// specifications are left implicit, as GCC 4.8 rejects explicit ones
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// that differ from them
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diff_frame(const diff_frame&) = default;
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diff_frame(diff_frame&&) = default;
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diff_frame& operator=(const diff_frame&) = default;
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diff_frame& operator=(diff_frame&&) = default;
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~diff_frame() = default;
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/// the values being diffed, both arrays or both objects
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const basic_json* source;
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const basic_json* target;
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/// the length of their path in `current_path`
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std::size_t path_length;
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/// arrays: the next index to diff
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std::size_t index = 0;
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/// objects: the next member of source to look at
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const_iterator member{}; // NOLINT(readability-redundant-member-init)
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/// objects: the keys common to both, in source's order
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std::vector<typename object_t::key_type> common_keys{}; // NOLINT(readability-redundant-member-init)
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/// objects: the next entry of common_keys
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std::size_t next_common = 0;
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/// objects: the "add" operations for keys only target has
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basic_json added_ops{}; // NOLINT(readability-redundant-member-init)
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};
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/// @ref diff for a @a source nested no more than @ref detail::recursion_depth_limit levels deep
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static basic_json diff_recursively(const basic_json& source, const basic_json& target,
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const string_t& path)
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{
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// the patch
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basic_json result(value_t::array);
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@@ -6115,7 +6022,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
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while (i < source.size() && i < target.size())
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{
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// recursive call to compare array values at index i
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auto temp_diff = diff_recursively(source[i], target[i], detail::concat<string_t>(path, '/', detail::to_string<string_t>(i)));
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auto temp_diff = diff(source[i], target[i], detail::concat<string_t>(path, '/', detail::to_string<string_t>(i)));
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result.insert(result.end(), temp_diff.begin(), temp_diff.end());
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++i;
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}
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@@ -6234,7 +6141,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
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if (common_it != common_keys_source_order.cend() && it.key() == *common_it)
|
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{
|
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const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
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auto temp_diff = diff_recursively(it.value(), target[it.key()], path_key);
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auto temp_diff = diff(it.value(), target[it.key()], path_key);
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result.insert(result.end(), temp_diff.begin(), temp_diff.end());
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++common_it;
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}
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@@ -6318,309 +6225,6 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
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|
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return result;
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}
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||||
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||||
/*!
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@brief @ref diff without the call stack
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Produces the same patch as @ref diff_recursively. Only used for a source
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nested more deeply than @ref detail::recursion_depth_limit; any arrays and objects
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below it that are not nested that deeply are diffed recursively.
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||||
*/
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static basic_json diff_iteratively(const basic_json& source, const basic_json& target,
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const string_t& path)
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{
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// the patch
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basic_json result(value_t::array);
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||||
|
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// The arrays and objects being diffed are kept on an explicit stack,
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||||
// and every pair of elements is still diffed completely before the
|
||||
// next one, so the operations come out in the same order as in
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// diff_recursively. The path of the values being diffed is kept in
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// one buffer that grows and shrinks with the stack, rather than in a
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// new string per level.
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std::vector<diff_frame> stack;
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string_t current_path = path;
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// diff `s` against `t`, whose path is current_path: primitives,
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||||
// values of different types, and objects whose members were reordered
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// are handled right away; arrays and other objects get a frame
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const auto enter = [&result, &stack, ¤t_path](const basic_json & s, const basic_json & t)
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||||
{
|
||||
// if the values are the same, there is nothing to do. Arrays and
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||||
// objects are not compared up front: comparing them recurses into
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||||
// everything below them - equal ones yield no operations anyway.
|
||||
if ((!s.is_structured() || !t.is_structured()) && s == t)
|
||||
{
|
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return;
|
||||
}
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||||
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||||
if (s.type() != t.type())
|
||||
{
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// different types: replace value
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result.push_back(
|
||||
{
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{"op", "replace"}, {"path", current_path}, {"value", t}
|
||||
});
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return;
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||||
}
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||||
|
||||
// arrays and objects that are not nested too deeply for the call
|
||||
// stack are diffed recursively, which can skip equal parts
|
||||
if (!nesting_exceeds(s, detail::recursion_depth_limit()))
|
||||
{
|
||||
const basic_json partial = diff_recursively(s, t, current_path);
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result.insert(result.end(), partial.begin(), partial.end());
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||||
return;
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||||
}
|
||||
|
||||
switch (s.type())
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||||
{
|
||||
case value_t::array:
|
||||
{
|
||||
stack.emplace_back(&s, &t, current_path.size());
|
||||
return;
|
||||
}
|
||||
|
||||
case value_t::object:
|
||||
{
|
||||
// first pass: record, for every source key, whether it is
|
||||
// common to both objects (in source's iteration order) or
|
||||
// was deleted (i.e., in source but not in target) -- this is
|
||||
// a by-product of the t.find() call already needed to
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||||
// tell the two cases apart, so it adds no extra lookups. The
|
||||
// "remove" ops themselves are emitted later, interleaved
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||||
// with the per-key diffs in the fast path below, to match
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||||
// source's original iteration order (as the original,
|
||||
// pre-reordering-aware implementation did) instead of
|
||||
// grouping all removes before all per-key diffs.
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||||
std::vector<typename object_t::key_type> common_keys_source_order;
|
||||
for (auto it = s.cbegin(); it != s.cend(); ++it)
|
||||
{
|
||||
if (t.find(it.key()) != t.end())
|
||||
{
|
||||
common_keys_source_order.push_back(it.key());
|
||||
}
|
||||
}
|
||||
|
||||
// second pass: find keys that were added (i.e., in target but
|
||||
// not in source), and record the keys common to both, in
|
||||
// target's iteration order -- again a by-product of the
|
||||
// s.find() call already needed to detect added keys. At
|
||||
// the same time, determine whether every added key comes
|
||||
// after every common key in target's order (a precondition
|
||||
// for the fast path below, which only ever appends new keys
|
||||
// at the very end): for an object_t whose iteration order is
|
||||
// a pure function of the key set (e.g. the default std::map,
|
||||
// which always iterates in sorted key order), the order
|
||||
// check further below is always true and this whole
|
||||
// mechanism is effectively a no-op; it only matters for a
|
||||
// reorderable object_t such as the one backing `ordered_json`.
|
||||
// patch ops for keys that were added (i.e., in target but not
|
||||
// in source); built here so the fast path below can reuse
|
||||
// them without a second s.find() per target key. Only
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||||
// used by the fast path -- the slow (reordering) path
|
||||
// rebuilds "add" ops for every key itself.
|
||||
std::vector<typename object_t::key_type> common_keys_target_order;
|
||||
basic_json added_ops(value_t::array);
|
||||
bool new_keys_form_suffix = true;
|
||||
bool seen_new_key = false;
|
||||
for (auto it = t.cbegin(); it != t.cend(); ++it)
|
||||
{
|
||||
if (s.find(it.key()) == s.end())
|
||||
{
|
||||
seen_new_key = true;
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
added_ops.push_back(
|
||||
{
|
||||
{"op", "add"}, {"path", path_key},
|
||||
{"value", it.value()}
|
||||
});
|
||||
}
|
||||
else
|
||||
{
|
||||
common_keys_target_order.push_back(it.key());
|
||||
if (seen_new_key)
|
||||
{
|
||||
new_keys_form_suffix = false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (common_keys_source_order == common_keys_target_order && new_keys_form_suffix)
|
||||
{
|
||||
// fast path: order of common keys already matches (or the
|
||||
// object_t's iteration order does not depend on
|
||||
// insertion history), so a plain per-key diff is correct
|
||||
// and minimal, as before. The frame walks source in
|
||||
// lockstep with common_keys_source_order, which is, by
|
||||
// construction, the subsequence of source's keys that
|
||||
// are common to both objects, in source's iteration
|
||||
// order -- so a cheap key comparison replaces another
|
||||
// lookup. Deleted keys are interleaved there too, in
|
||||
// source's original order, and the "add" ops collected
|
||||
// above are appended once all members are done.
|
||||
stack.emplace_back(&s, &t, current_path.size());
|
||||
stack.back().member = s.cbegin();
|
||||
stack.back().common_keys = std::move(common_keys_source_order);
|
||||
stack.back().added_ops = std::move(added_ops);
|
||||
return;
|
||||
}
|
||||
|
||||
// slow path: the common keys are in a different relative
|
||||
// order in source and target (only possible for a
|
||||
// reorderable object_t like ordered_map). Building a
|
||||
// minimal reordering patch is a nontrivial (LCS-like)
|
||||
// problem; instead, remove every source key -- both
|
||||
// deleted keys (which must be removed regardless) and
|
||||
// common keys (removed so they can be re-added in
|
||||
// target's order) -- and re-add every key that should
|
||||
// remain, with its final target value, in target's
|
||||
// order. basic_json::patch()'s "add" operation on an
|
||||
// object uses operator[], which appends at the end for a
|
||||
// vector-backed insertion-ordered map when the key does
|
||||
// not already exist -- so removing a key and then adding
|
||||
// it moves it to the end, fixing its position.
|
||||
for (auto it = s.cbegin(); it != s.cend(); ++it)
|
||||
{
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
result.push_back(object(
|
||||
{
|
||||
{"op", "remove"}, {"path", path_key}
|
||||
}));
|
||||
}
|
||||
|
||||
// add every key that is either common (just removed
|
||||
// above) or brand new, in target's iteration order, so
|
||||
// that the final order after applying the patch matches
|
||||
// target exactly
|
||||
for (auto it = t.cbegin(); it != t.cend(); ++it)
|
||||
{
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "add"}, {"path", path_key},
|
||||
{"value", it.value()}
|
||||
});
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
case value_t::null:
|
||||
case value_t::string:
|
||||
case value_t::boolean:
|
||||
case value_t::number_integer:
|
||||
case value_t::number_unsigned:
|
||||
case value_t::number_float:
|
||||
case value_t::binary:
|
||||
case value_t::discarded:
|
||||
default:
|
||||
{
|
||||
// both primitive types: replace value
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "replace"}, {"path", current_path}, {"value", t}
|
||||
});
|
||||
return;
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
enter(source, target);
|
||||
while (!stack.empty())
|
||||
{
|
||||
diff_frame& frame = stack.back();
|
||||
const std::size_t path_length = frame.path_length;
|
||||
const std::size_t depth = stack.size();
|
||||
|
||||
if (frame.source->is_array())
|
||||
{
|
||||
const auto& source_array = *frame.source->m_data.m_value.array;
|
||||
const auto& target_array = *frame.target->m_data.m_value.array;
|
||||
|
||||
// first pass: traverse common elements
|
||||
if (frame.index < source_array.size() && frame.index < target_array.size())
|
||||
{
|
||||
const std::size_t i = frame.index++;
|
||||
detail::concat_into(current_path, '/', detail::to_string<string_t>(i));
|
||||
enter(source_array[i], target_array[i]); // may push, which invalidates `frame`
|
||||
if (stack.size() == depth)
|
||||
{
|
||||
current_path.resize(path_length);
|
||||
}
|
||||
continue;
|
||||
}
|
||||
|
||||
// We now reached the end of at least one array
|
||||
// in a second pass, traverse the remaining elements
|
||||
|
||||
// remove my remaining elements, highest index first; appending
|
||||
// in that order avoids the quadratic reinsertion done before
|
||||
for (std::size_t j = source_array.size(); j > frame.index; --j)
|
||||
{
|
||||
result.push_back(object(
|
||||
{
|
||||
{"op", "remove"},
|
||||
{"path", detail::concat<string_t>(current_path, '/', detail::to_string<string_t>(j - 1))}
|
||||
}));
|
||||
}
|
||||
|
||||
// add other remaining elements
|
||||
for (std::size_t i = source_array.size(); i < target_array.size(); ++i)
|
||||
{
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "add"},
|
||||
{"path", detail::concat<string_t>(current_path, "/-")},
|
||||
{"value", target_array[i]}
|
||||
});
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
if (frame.member != frame.source->cend())
|
||||
{
|
||||
const const_iterator it = frame.member;
|
||||
++frame.member;
|
||||
if (frame.next_common < frame.common_keys.size() && it.key() == frame.common_keys[frame.next_common])
|
||||
{
|
||||
++frame.next_common;
|
||||
const basic_json& target_value = (*frame.target)[it.key()];
|
||||
detail::concat_into(current_path, '/', detail::escape(it.key()));
|
||||
enter(it.value(), target_value); // may push, which invalidates `frame`
|
||||
if (stack.size() == depth)
|
||||
{
|
||||
current_path.resize(path_length);
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
// found a key that is not in target -> remove it
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
result.push_back(object(
|
||||
{
|
||||
{"op", "remove"}, {"path", path_key}
|
||||
}));
|
||||
}
|
||||
continue;
|
||||
}
|
||||
|
||||
// append the "add" ops for brand-new keys collected when the
|
||||
// object was entered
|
||||
result.insert(result.end(), frame.added_ops.begin(), frame.added_ops.end());
|
||||
}
|
||||
|
||||
// this array or object is done: continue with the one it is in
|
||||
stack.pop_back();
|
||||
if (!stack.empty())
|
||||
{
|
||||
current_path.resize(stack.back().path_length);
|
||||
}
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
public:
|
||||
/// @}
|
||||
|
||||
////////////////////////////////
|
||||
|
||||
@@ -25648,7 +25648,8 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
using copy_worklist_t = std::vector<std::pair<const basic_json*, basic_json*>>;
|
||||
|
||||
/// scratch space to build the key skeleton of an object copy in one go
|
||||
using copy_scratch_t = std::vector<std::pair<typename object_t::key_type, basic_json>>;
|
||||
using copy_scratch_value_t = std::pair<typename object_t::key_type, basic_json>;
|
||||
using copy_scratch_t = std::vector<copy_scratch_value_t, AllocatorType<copy_scratch_value_t>>;
|
||||
|
||||
/// @brief copy everything of @a src into @a dst but its type and value
|
||||
static void copy_metadata(const basic_json& src, basic_json& dst)
|
||||
@@ -30637,100 +30638,6 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
JSON_HEDLEY_WARN_UNUSED_RESULT
|
||||
static basic_json diff(const basic_json& source, const basic_json& target,
|
||||
const string_t& path = "")
|
||||
{
|
||||
// Diffing descends into both values once per nesting level and
|
||||
// compares them with operator== on the way, which recurses as well,
|
||||
// so values nested deeply enough used to exhaust the call stack.
|
||||
// Both only descend as far as the source is nested, so a source
|
||||
// nested no more than detail::recursion_depth_limit() levels deep -
|
||||
// all but a vanishing minority - is diffed recursively as before;
|
||||
// deeper ones are diffed without the call stack.
|
||||
if (JSON_HEDLEY_LIKELY(!nesting_exceeds(source, detail::recursion_depth_limit())))
|
||||
{
|
||||
return diff_recursively(source, target, path);
|
||||
}
|
||||
return diff_iteratively(source, target, path);
|
||||
}
|
||||
|
||||
private:
|
||||
/*!
|
||||
@brief whether @a j is nested more than @a limit levels deep
|
||||
|
||||
A primitive value is not nested at all, an array or object one level more
|
||||
than its most deeply nested element. Recurses at most @a limit levels.
|
||||
*/
|
||||
static bool nesting_exceeds(const basic_json& j, const std::size_t limit)
|
||||
{
|
||||
switch (j.m_data.m_type)
|
||||
{
|
||||
case value_t::array:
|
||||
{
|
||||
return limit == 0 || std::any_of(j.m_data.m_value.array->cbegin(), j.m_data.m_value.array->cend(),
|
||||
[limit](const basic_json & element)
|
||||
{
|
||||
return element.is_structured() && nesting_exceeds(element, limit - 1);
|
||||
});
|
||||
}
|
||||
|
||||
case value_t::object:
|
||||
{
|
||||
return limit == 0 || std::any_of(j.m_data.m_value.object->cbegin(), j.m_data.m_value.object->cend(),
|
||||
[limit](const typename object_t::value_type & element)
|
||||
{
|
||||
return element.second.is_structured() && nesting_exceeds(element.second, limit - 1);
|
||||
});
|
||||
}
|
||||
|
||||
case value_t::null:
|
||||
case value_t::string:
|
||||
case value_t::boolean:
|
||||
case value_t::number_integer:
|
||||
case value_t::number_unsigned:
|
||||
case value_t::number_float:
|
||||
case value_t::binary:
|
||||
case value_t::discarded:
|
||||
default:
|
||||
return false;
|
||||
}
|
||||
}
|
||||
|
||||
/// @brief two arrays or two objects @ref diff_iteratively is diffing
|
||||
struct diff_frame
|
||||
{
|
||||
diff_frame(const basic_json* source_, const basic_json* target_, const std::size_t path_length_) noexcept
|
||||
: source(source_), target(target_), path_length(path_length_)
|
||||
{}
|
||||
|
||||
// declared for GCC's -Weffc++, which asks for them in a class with
|
||||
// pointer members and a non-trivial destructor; the exception
|
||||
// specifications are left implicit, as GCC 4.8 rejects explicit ones
|
||||
// that differ from them
|
||||
diff_frame(const diff_frame&) = default;
|
||||
diff_frame(diff_frame&&) = default;
|
||||
diff_frame& operator=(const diff_frame&) = default;
|
||||
diff_frame& operator=(diff_frame&&) = default;
|
||||
~diff_frame() = default;
|
||||
|
||||
/// the values being diffed, both arrays or both objects
|
||||
const basic_json* source;
|
||||
const basic_json* target;
|
||||
/// the length of their path in `current_path`
|
||||
std::size_t path_length;
|
||||
/// arrays: the next index to diff
|
||||
std::size_t index = 0;
|
||||
/// objects: the next member of source to look at
|
||||
const_iterator member{}; // NOLINT(readability-redundant-member-init)
|
||||
/// objects: the keys common to both, in source's order
|
||||
std::vector<typename object_t::key_type> common_keys{}; // NOLINT(readability-redundant-member-init)
|
||||
/// objects: the next entry of common_keys
|
||||
std::size_t next_common = 0;
|
||||
/// objects: the "add" operations for keys only target has
|
||||
basic_json added_ops{}; // NOLINT(readability-redundant-member-init)
|
||||
};
|
||||
|
||||
/// @ref diff for a @a source nested no more than @ref detail::recursion_depth_limit levels deep
|
||||
static basic_json diff_recursively(const basic_json& source, const basic_json& target,
|
||||
const string_t& path)
|
||||
{
|
||||
// the patch
|
||||
basic_json result(value_t::array);
|
||||
@@ -30760,7 +30667,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
while (i < source.size() && i < target.size())
|
||||
{
|
||||
// recursive call to compare array values at index i
|
||||
auto temp_diff = diff_recursively(source[i], target[i], detail::concat<string_t>(path, '/', detail::to_string<string_t>(i)));
|
||||
auto temp_diff = diff(source[i], target[i], detail::concat<string_t>(path, '/', detail::to_string<string_t>(i)));
|
||||
result.insert(result.end(), temp_diff.begin(), temp_diff.end());
|
||||
++i;
|
||||
}
|
||||
@@ -30879,7 +30786,7 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
if (common_it != common_keys_source_order.cend() && it.key() == *common_it)
|
||||
{
|
||||
const auto path_key = detail::concat<string_t>(path, '/', detail::escape(it.key()));
|
||||
auto temp_diff = diff_recursively(it.value(), target[it.key()], path_key);
|
||||
auto temp_diff = diff(it.value(), target[it.key()], path_key);
|
||||
result.insert(result.end(), temp_diff.begin(), temp_diff.end());
|
||||
++common_it;
|
||||
}
|
||||
@@ -30963,309 +30870,6 @@ class basic_json // NOLINT(cppcoreguidelines-special-member-functions,hicpp-spec
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
/*!
|
||||
@brief @ref diff without the call stack
|
||||
|
||||
Produces the same patch as @ref diff_recursively. Only used for a source
|
||||
nested more deeply than @ref detail::recursion_depth_limit; any arrays and objects
|
||||
below it that are not nested that deeply are diffed recursively.
|
||||
*/
|
||||
static basic_json diff_iteratively(const basic_json& source, const basic_json& target,
|
||||
const string_t& path)
|
||||
{
|
||||
// the patch
|
||||
basic_json result(value_t::array);
|
||||
|
||||
// The arrays and objects being diffed are kept on an explicit stack,
|
||||
// and every pair of elements is still diffed completely before the
|
||||
// next one, so the operations come out in the same order as in
|
||||
// diff_recursively. The path of the values being diffed is kept in
|
||||
// one buffer that grows and shrinks with the stack, rather than in a
|
||||
// new string per level.
|
||||
std::vector<diff_frame> stack;
|
||||
string_t current_path = path;
|
||||
|
||||
// diff `s` against `t`, whose path is current_path: primitives,
|
||||
// values of different types, and objects whose members were reordered
|
||||
// are handled right away; arrays and other objects get a frame
|
||||
const auto enter = [&result, &stack, ¤t_path](const basic_json & s, const basic_json & t)
|
||||
{
|
||||
// if the values are the same, there is nothing to do. Arrays and
|
||||
// objects are not compared up front: comparing them recurses into
|
||||
// everything below them - equal ones yield no operations anyway.
|
||||
if ((!s.is_structured() || !t.is_structured()) && s == t)
|
||||
{
|
||||
return;
|
||||
}
|
||||
|
||||
if (s.type() != t.type())
|
||||
{
|
||||
// different types: replace value
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "replace"}, {"path", current_path}, {"value", t}
|
||||
});
|
||||
return;
|
||||
}
|
||||
|
||||
// arrays and objects that are not nested too deeply for the call
|
||||
// stack are diffed recursively, which can skip equal parts
|
||||
if (!nesting_exceeds(s, detail::recursion_depth_limit()))
|
||||
{
|
||||
const basic_json partial = diff_recursively(s, t, current_path);
|
||||
result.insert(result.end(), partial.begin(), partial.end());
|
||||
return;
|
||||
}
|
||||
|
||||
switch (s.type())
|
||||
{
|
||||
case value_t::array:
|
||||
{
|
||||
stack.emplace_back(&s, &t, current_path.size());
|
||||
return;
|
||||
}
|
||||
|
||||
case value_t::object:
|
||||
{
|
||||
// first pass: record, for every source key, whether it is
|
||||
// common to both objects (in source's iteration order) or
|
||||
// was deleted (i.e., in source but not in target) -- this is
|
||||
// a by-product of the t.find() call already needed to
|
||||
// tell the two cases apart, so it adds no extra lookups. The
|
||||
// "remove" ops themselves are emitted later, interleaved
|
||||
// with the per-key diffs in the fast path below, to match
|
||||
// source's original iteration order (as the original,
|
||||
// pre-reordering-aware implementation did) instead of
|
||||
// grouping all removes before all per-key diffs.
|
||||
std::vector<typename object_t::key_type> common_keys_source_order;
|
||||
for (auto it = s.cbegin(); it != s.cend(); ++it)
|
||||
{
|
||||
if (t.find(it.key()) != t.end())
|
||||
{
|
||||
common_keys_source_order.push_back(it.key());
|
||||
}
|
||||
}
|
||||
|
||||
// second pass: find keys that were added (i.e., in target but
|
||||
// not in source), and record the keys common to both, in
|
||||
// target's iteration order -- again a by-product of the
|
||||
// s.find() call already needed to detect added keys. At
|
||||
// the same time, determine whether every added key comes
|
||||
// after every common key in target's order (a precondition
|
||||
// for the fast path below, which only ever appends new keys
|
||||
// at the very end): for an object_t whose iteration order is
|
||||
// a pure function of the key set (e.g. the default std::map,
|
||||
// which always iterates in sorted key order), the order
|
||||
// check further below is always true and this whole
|
||||
// mechanism is effectively a no-op; it only matters for a
|
||||
// reorderable object_t such as the one backing `ordered_json`.
|
||||
// patch ops for keys that were added (i.e., in target but not
|
||||
// in source); built here so the fast path below can reuse
|
||||
// them without a second s.find() per target key. Only
|
||||
// used by the fast path -- the slow (reordering) path
|
||||
// rebuilds "add" ops for every key itself.
|
||||
std::vector<typename object_t::key_type> common_keys_target_order;
|
||||
basic_json added_ops(value_t::array);
|
||||
bool new_keys_form_suffix = true;
|
||||
bool seen_new_key = false;
|
||||
for (auto it = t.cbegin(); it != t.cend(); ++it)
|
||||
{
|
||||
if (s.find(it.key()) == s.end())
|
||||
{
|
||||
seen_new_key = true;
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
added_ops.push_back(
|
||||
{
|
||||
{"op", "add"}, {"path", path_key},
|
||||
{"value", it.value()}
|
||||
});
|
||||
}
|
||||
else
|
||||
{
|
||||
common_keys_target_order.push_back(it.key());
|
||||
if (seen_new_key)
|
||||
{
|
||||
new_keys_form_suffix = false;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
if (common_keys_source_order == common_keys_target_order && new_keys_form_suffix)
|
||||
{
|
||||
// fast path: order of common keys already matches (or the
|
||||
// object_t's iteration order does not depend on
|
||||
// insertion history), so a plain per-key diff is correct
|
||||
// and minimal, as before. The frame walks source in
|
||||
// lockstep with common_keys_source_order, which is, by
|
||||
// construction, the subsequence of source's keys that
|
||||
// are common to both objects, in source's iteration
|
||||
// order -- so a cheap key comparison replaces another
|
||||
// lookup. Deleted keys are interleaved there too, in
|
||||
// source's original order, and the "add" ops collected
|
||||
// above are appended once all members are done.
|
||||
stack.emplace_back(&s, &t, current_path.size());
|
||||
stack.back().member = s.cbegin();
|
||||
stack.back().common_keys = std::move(common_keys_source_order);
|
||||
stack.back().added_ops = std::move(added_ops);
|
||||
return;
|
||||
}
|
||||
|
||||
// slow path: the common keys are in a different relative
|
||||
// order in source and target (only possible for a
|
||||
// reorderable object_t like ordered_map). Building a
|
||||
// minimal reordering patch is a nontrivial (LCS-like)
|
||||
// problem; instead, remove every source key -- both
|
||||
// deleted keys (which must be removed regardless) and
|
||||
// common keys (removed so they can be re-added in
|
||||
// target's order) -- and re-add every key that should
|
||||
// remain, with its final target value, in target's
|
||||
// order. basic_json::patch()'s "add" operation on an
|
||||
// object uses operator[], which appends at the end for a
|
||||
// vector-backed insertion-ordered map when the key does
|
||||
// not already exist -- so removing a key and then adding
|
||||
// it moves it to the end, fixing its position.
|
||||
for (auto it = s.cbegin(); it != s.cend(); ++it)
|
||||
{
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
result.push_back(object(
|
||||
{
|
||||
{"op", "remove"}, {"path", path_key}
|
||||
}));
|
||||
}
|
||||
|
||||
// add every key that is either common (just removed
|
||||
// above) or brand new, in target's iteration order, so
|
||||
// that the final order after applying the patch matches
|
||||
// target exactly
|
||||
for (auto it = t.cbegin(); it != t.cend(); ++it)
|
||||
{
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "add"}, {"path", path_key},
|
||||
{"value", it.value()}
|
||||
});
|
||||
}
|
||||
return;
|
||||
}
|
||||
|
||||
case value_t::null:
|
||||
case value_t::string:
|
||||
case value_t::boolean:
|
||||
case value_t::number_integer:
|
||||
case value_t::number_unsigned:
|
||||
case value_t::number_float:
|
||||
case value_t::binary:
|
||||
case value_t::discarded:
|
||||
default:
|
||||
{
|
||||
// both primitive types: replace value
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "replace"}, {"path", current_path}, {"value", t}
|
||||
});
|
||||
return;
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
enter(source, target);
|
||||
while (!stack.empty())
|
||||
{
|
||||
diff_frame& frame = stack.back();
|
||||
const std::size_t path_length = frame.path_length;
|
||||
const std::size_t depth = stack.size();
|
||||
|
||||
if (frame.source->is_array())
|
||||
{
|
||||
const auto& source_array = *frame.source->m_data.m_value.array;
|
||||
const auto& target_array = *frame.target->m_data.m_value.array;
|
||||
|
||||
// first pass: traverse common elements
|
||||
if (frame.index < source_array.size() && frame.index < target_array.size())
|
||||
{
|
||||
const std::size_t i = frame.index++;
|
||||
detail::concat_into(current_path, '/', detail::to_string<string_t>(i));
|
||||
enter(source_array[i], target_array[i]); // may push, which invalidates `frame`
|
||||
if (stack.size() == depth)
|
||||
{
|
||||
current_path.resize(path_length);
|
||||
}
|
||||
continue;
|
||||
}
|
||||
|
||||
// We now reached the end of at least one array
|
||||
// in a second pass, traverse the remaining elements
|
||||
|
||||
// remove my remaining elements, highest index first; appending
|
||||
// in that order avoids the quadratic reinsertion done before
|
||||
for (std::size_t j = source_array.size(); j > frame.index; --j)
|
||||
{
|
||||
result.push_back(object(
|
||||
{
|
||||
{"op", "remove"},
|
||||
{"path", detail::concat<string_t>(current_path, '/', detail::to_string<string_t>(j - 1))}
|
||||
}));
|
||||
}
|
||||
|
||||
// add other remaining elements
|
||||
for (std::size_t i = source_array.size(); i < target_array.size(); ++i)
|
||||
{
|
||||
result.push_back(
|
||||
{
|
||||
{"op", "add"},
|
||||
{"path", detail::concat<string_t>(current_path, "/-")},
|
||||
{"value", target_array[i]}
|
||||
});
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
if (frame.member != frame.source->cend())
|
||||
{
|
||||
const const_iterator it = frame.member;
|
||||
++frame.member;
|
||||
if (frame.next_common < frame.common_keys.size() && it.key() == frame.common_keys[frame.next_common])
|
||||
{
|
||||
++frame.next_common;
|
||||
const basic_json& target_value = (*frame.target)[it.key()];
|
||||
detail::concat_into(current_path, '/', detail::escape(it.key()));
|
||||
enter(it.value(), target_value); // may push, which invalidates `frame`
|
||||
if (stack.size() == depth)
|
||||
{
|
||||
current_path.resize(path_length);
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
// found a key that is not in target -> remove it
|
||||
const auto path_key = detail::concat<string_t>(current_path, '/', detail::escape(it.key()));
|
||||
result.push_back(object(
|
||||
{
|
||||
{"op", "remove"}, {"path", path_key}
|
||||
}));
|
||||
}
|
||||
continue;
|
||||
}
|
||||
|
||||
// append the "add" ops for brand-new keys collected when the
|
||||
// object was entered
|
||||
result.insert(result.end(), frame.added_ops.begin(), frame.added_ops.end());
|
||||
}
|
||||
|
||||
// this array or object is done: continue with the one it is in
|
||||
stack.pop_back();
|
||||
if (!stack.empty())
|
||||
{
|
||||
current_path.resize(stack.back().path_length);
|
||||
}
|
||||
}
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
public:
|
||||
/// @}
|
||||
|
||||
////////////////////////////////
|
||||
|
||||
@@ -270,6 +270,82 @@ TEST_CASE("controlled bad_alloc")
|
||||
}
|
||||
}
|
||||
|
||||
namespace
|
||||
{
|
||||
// counts the allocations of pairs with a non-const first member: the object
|
||||
// types store std::pair<const Key, T>, so only the scratch space of the
|
||||
// iterative deep copy allocates std::pair<Key, T>
|
||||
std::size_t scratch_pair_allocations = 0;
|
||||
|
||||
template<class T>
|
||||
struct is_scratch_pair : std::false_type {};
|
||||
|
||||
template<class K, class V>
|
||||
struct is_scratch_pair<std::pair<K, V>> : std::integral_constant < bool, !std::is_const<K>::value > {};
|
||||
|
||||
template<class T>
|
||||
struct scratch_counting_allocator : std::allocator<T>
|
||||
{
|
||||
using std::allocator<T>::allocator;
|
||||
|
||||
T* allocate(std::size_t n)
|
||||
{
|
||||
if (is_scratch_pair<T>::value)
|
||||
{
|
||||
++scratch_pair_allocations;
|
||||
}
|
||||
return std::allocator<T>::allocate(n);
|
||||
}
|
||||
|
||||
#ifdef __cpp_lib_allocate_at_least
|
||||
// std::allocator<T>::allocate_at_least would bypass the counting, and
|
||||
// libc++'s containers prefer it over allocate from C++23 on
|
||||
auto allocate_at_least(std::size_t n)
|
||||
{
|
||||
if (is_scratch_pair<T>::value)
|
||||
{
|
||||
++scratch_pair_allocations;
|
||||
}
|
||||
return std::allocator<T>::allocate_at_least(n);
|
||||
}
|
||||
#endif
|
||||
|
||||
template <class U>
|
||||
struct rebind
|
||||
{
|
||||
using other = scratch_counting_allocator<U>;
|
||||
};
|
||||
};
|
||||
} // namespace
|
||||
|
||||
TEST_CASE("deep copy uses the provided allocator")
|
||||
{
|
||||
using counting_json = nlohmann::basic_json<std::map,
|
||||
std::vector,
|
||||
std::string,
|
||||
bool,
|
||||
std::int64_t,
|
||||
std::uint64_t,
|
||||
double,
|
||||
scratch_counting_allocator>;
|
||||
|
||||
// deeper than the 128 levels the copy constructor descends into, so the
|
||||
// innermost objects are copied by the iterative deep copy
|
||||
counting_json j = 1;
|
||||
for (std::size_t i = 0; i < 300; ++i)
|
||||
{
|
||||
counting_json wrapper = counting_json::object();
|
||||
wrapper["a"] = std::move(j);
|
||||
j = std::move(wrapper);
|
||||
}
|
||||
|
||||
scratch_pair_allocations = 0;
|
||||
// NOLINTNEXTLINE(performance-unnecessary-copy-initialization): the copy is what is tested
|
||||
const counting_json copy(j);
|
||||
CHECK(scratch_pair_allocations > 0);
|
||||
CHECK(copy == j);
|
||||
}
|
||||
|
||||
namespace
|
||||
{
|
||||
template<class T>
|
||||
|
||||
@@ -15,65 +15,8 @@ using nlohmann::json;
|
||||
#endif
|
||||
|
||||
#include <fstream>
|
||||
#include <string>
|
||||
#include <vector>
|
||||
#include "make_test_data_available.hpp"
|
||||
|
||||
namespace
|
||||
{
|
||||
// alternating objects and arrays nested `depth` levels deep, with members that
|
||||
// depend on `variant` at some levels, so diffing two variants yields
|
||||
// operations on many levels: replacing the innermost value, adding, removing,
|
||||
// and (for ordered_json) reordering members, and changing array lengths
|
||||
template<typename BasicJsonType>
|
||||
BasicJsonType nested(const std::size_t depth, const int variant)
|
||||
{
|
||||
BasicJsonType value = variant;
|
||||
for (std::size_t i = 0; i < depth; ++i)
|
||||
{
|
||||
if (i % 2 == 0)
|
||||
{
|
||||
BasicJsonType object = BasicJsonType::object();
|
||||
if ((i + static_cast<std::size_t>(variant)) % 7 == 0)
|
||||
{
|
||||
object["x"] = i;
|
||||
}
|
||||
if (variant == 2 && i % 11 == 0)
|
||||
{
|
||||
object["z"] = "z";
|
||||
}
|
||||
object["a"] = std::move(value);
|
||||
if (variant == 1 && i % 5 == 0)
|
||||
{
|
||||
object["y"] = 1;
|
||||
}
|
||||
value = std::move(object);
|
||||
}
|
||||
else
|
||||
{
|
||||
BasicJsonType array = BasicJsonType::array({std::move(value)});
|
||||
if ((i + static_cast<std::size_t>(variant)) % 3 == 0)
|
||||
{
|
||||
array.push_back(i);
|
||||
}
|
||||
value = std::move(array);
|
||||
}
|
||||
}
|
||||
return value;
|
||||
}
|
||||
|
||||
// a path of `depth` reference tokens, as nested() nests its values
|
||||
std::string nested_path(const std::size_t depth)
|
||||
{
|
||||
std::string path;
|
||||
for (std::size_t i = depth; i > 0; --i)
|
||||
{
|
||||
path += (i - 1) % 2 == 0 ? "/a" : "/0";
|
||||
}
|
||||
return path;
|
||||
}
|
||||
} // namespace
|
||||
|
||||
TEST_CASE("JSON patch")
|
||||
{
|
||||
SECTION("examples from RFC 6902")
|
||||
@@ -1808,99 +1751,3 @@ TEST_CASE("JSON patch - diff emits array removals in descending index order")
|
||||
CHECK(source.patch(patch) == target);
|
||||
}
|
||||
}
|
||||
|
||||
TEST_CASE("JSON patch: diff of deeply nested values")
|
||||
{
|
||||
SECTION("the diff reproduces the target at every depth")
|
||||
{
|
||||
// depths on either side of the nesting depth up to which diff()
|
||||
// recurses (detail::recursion_depth_limit(), 128); not every depth up
|
||||
// to 300, as the test would then time out under Valgrind
|
||||
std::vector<std::size_t> depths;
|
||||
for (std::size_t depth = 0; depth <= 16; ++depth)
|
||||
{
|
||||
depths.push_back(depth);
|
||||
}
|
||||
for (std::size_t depth = 120; depth <= 136; ++depth)
|
||||
{
|
||||
depths.push_back(depth);
|
||||
}
|
||||
depths.push_back(300);
|
||||
|
||||
for (const auto depth : depths)
|
||||
{
|
||||
CAPTURE(depth);
|
||||
for (int from = 0; from < 3; ++from)
|
||||
{
|
||||
for (int to = 0; to < 3; ++to)
|
||||
{
|
||||
CAPTURE(from);
|
||||
CAPTURE(to);
|
||||
const auto source = nested<json>(depth, from);
|
||||
const auto target = nested<json>(depth, to);
|
||||
const auto patch = json::diff(source, target);
|
||||
CHECK(source.patch(patch) == target);
|
||||
CHECK(patch.empty() == (from == to));
|
||||
|
||||
const auto ordered_source = nested<nlohmann::ordered_json>(depth, from);
|
||||
const auto ordered_target = nested<nlohmann::ordered_json>(depth, to);
|
||||
CHECK(ordered_source.patch(nlohmann::ordered_json::diff(ordered_source, ordered_target)) == ordered_target);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
SECTION("a difference only in the innermost value is one replace operation")
|
||||
{
|
||||
for (std::size_t depth = 0; depth <= 300; ++depth)
|
||||
{
|
||||
CAPTURE(depth);
|
||||
json source = 1;
|
||||
json target = 2;
|
||||
for (std::size_t i = 0; i < depth; ++i)
|
||||
{
|
||||
source = i % 2 == 0 ? json::object({{"a", std::move(source)}}) : json::array({std::move(source)});
|
||||
target = i % 2 == 0 ? json::object({{"a", std::move(target)}}) : json::array({std::move(target)});
|
||||
}
|
||||
CHECK(json::diff(source, target, "/root") == json::array({{{"op", "replace"}, {"path", "/root" + nested_path(depth)}, {"value", 2}}}));
|
||||
}
|
||||
}
|
||||
|
||||
SECTION("values nested too deeply for the call stack (#5393)")
|
||||
{
|
||||
// diff() used to recurse once per nesting level, and compared the
|
||||
// values with operator== on every level. The values are only
|
||||
// parsed and diffed, never copied or compared, since those recurse
|
||||
// too.
|
||||
const std::size_t depth = 100000;
|
||||
for (const bool objects :
|
||||
{
|
||||
false, true
|
||||
})
|
||||
{
|
||||
CAPTURE(objects);
|
||||
std::string source_text;
|
||||
std::string target_text;
|
||||
std::string equal_text;
|
||||
std::string path;
|
||||
for (std::size_t i = 0; i < depth; ++i)
|
||||
{
|
||||
source_text += objects ? "{\"a\":" : "[";
|
||||
path += objects ? "/a" : "/0";
|
||||
}
|
||||
target_text = source_text + "2";
|
||||
equal_text = source_text + "1";
|
||||
source_text += "1";
|
||||
const std::string closing(depth, objects ? '}' : ']');
|
||||
const auto source = json::parse(source_text + closing);
|
||||
|
||||
const auto patch = json::diff(source, json::parse(target_text + closing));
|
||||
REQUIRE(patch.size() == 1);
|
||||
CHECK(patch[0]["op"] == "replace");
|
||||
CHECK(patch[0]["path"] == path);
|
||||
CHECK(patch[0]["value"] == 2);
|
||||
|
||||
CHECK(json::diff(source, json::parse(equal_text + closing)).empty());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user