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Merge branch 'feature/json-patch' into develop

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Niels 2016-05-07 18:41:02 +02:00
parent 74544b42af c04275966f
commit 688cd49bdc
21 changed files with 2785 additions and 311 deletions
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2
.travis.yml
View file

@ -109,6 +109,8 @@ matrix:
env: COMPILER=clang
script:
- uname -a
- $COMPILER --version
- make CXX=$COMPILER CXXFLAGS="-lstdc++"
- ./json_unit "*"
- if [ `which valgrind` ]; then

5
ChangeLog.md
View file

@ -5,10 +5,12 @@ All notable changes to this project will be documented in this file. This projec
[Full Changelog](https://github.com/nlohmann/json/compare/v1.1.0...HEAD)
- Additional integration options [\#237](https://github.com/nlohmann/json/issues/237)
- Can't use basic\_json::iterator as a base iterator for std::move\_iterator [\#233](https://github.com/nlohmann/json/issues/233)
- Provide a FAQ [\#163](https://github.com/nlohmann/json/issues/163)
- Create PULL\_REQUEST\_TEMPLATE.md [\#213](https://github.com/nlohmann/json/pull/213) ([whackashoe](https://github.com/whackashoe))
- fixed noexcept; added constexpr [\#208](https://github.com/nlohmann/json/pull/208) ([nlohmann](https://github.com/nlohmann))
- Add support for afl-fuzz testing [\#207](https://github.com/nlohmann/json/pull/207) ([msm-](https://github.com/msm-))
- Add support for afl-fuzz testing [\#207](https://github.com/nlohmann/json/pull/207) ([mykter](https://github.com/mykter))
- Issue \#178 - Extending support to full uint64\_t/int64\_t range and unsigned type \(updated\) [\#193](https://github.com/nlohmann/json/pull/193) ([twelsby](https://github.com/twelsby))
- double values are serialized with commas as decimal points [\#228](https://github.com/nlohmann/json/issues/228)
@ -26,6 +28,7 @@ All notable changes to this project will be documented in this file. This projec
- Conflicting typedef of ssize\_t on Windows 32 bit when using Boost.Python [\#204](https://github.com/nlohmann/json/issues/204)
- Integer conversion to unsigned [\#178](https://github.com/nlohmann/json/issues/178)
- Implement additional integration options [\#238](https://github.com/nlohmann/json/pull/238) ([robertmrk](https://github.com/robertmrk))
- make serialization locale-independent [\#232](https://github.com/nlohmann/json/pull/232) ([nlohmann](https://github.com/nlohmann))
- fixes \#223 by updating README.md [\#227](https://github.com/nlohmann/json/pull/227) ([kevin--](https://github.com/kevin--))
- Use namespace std for int64\_t and uint64\_t [\#226](https://github.com/nlohmann/json/pull/226) ([lv-zheng](https://github.com/lv-zheng))

23
README.md
View file

@ -48,6 +48,8 @@ Though it's 2016 already, the support for C++11 is still a bit sparse. Currently
- Clang 3.4 - 3.9 (and possibly later)
- Microsoft Visual C++ 14.0 RC (and possibly later)
The code is currently checked with Travis for GCC 4.9, GCC
I would be happy to learn about other compilers/versions.
Please note:
@ -63,6 +65,25 @@ Please note:
- For GCC running on MinGW or Android SDK, the error `'to_string' is not a member of 'std'` (or similarly, for `strtod`) may occur. Note this is not an issue with the code, but rather with the compiler itself. On Android, see above to build with a newer environment. For MinGW, please refer to [this site](http://tehsausage.com/mingw-to-string) and [this discussion](https://github.com/nlohmann/json/issues/136) for information on how to fix this bug.
The following compilers are currently used in [continuous integration](https://travis-ci.org/nlohmann/json):
| Compiler | Operating System | Version String |
|-----------------|------------------------------|----------------|
| GCC 4.9.3 | Ubuntu 14.04.3 LTS | g++-4.9 (Ubuntu 4.9.3-8ubuntu2~14.04) 4.9.3 |
| GCC 5.3.0 | Ubuntu 14.04.3 LTS | g++-5 (Ubuntu 5.3.0-3ubuntu1~14.04) 5.3.0 20151204 |
| Clang 3.6.2 | Ubuntu 14.04.3 LTS | Ubuntu clang version 3.6.2-svn240577-1~exp1 (branches/release_36) (based on LLVM 3.6.2) |
| Clang 3.7.1 | Ubuntu 14.04.3 LTS | Ubuntu clang version 3.7.1-svn253571-1~exp1 (branches/release_37) (based on LLVM 3.7.1) |
| Clang 3.8.1 | Ubuntu 14.04.3 LTS | clang version 3.8.1-svn265380-1~exp1 (branches/release_38) |
| Clang 3.9.0 | Ubuntu 14.04.3 LTS | clang version 3.9.0-svn267478-1~exp1 (trunk) |
| Clang Xcode 6.1 | Darwin Kernel Version 13.4.0 | Apple LLVM version 6.0 (clang-600.0.54) (based on LLVM 3.5svn) |
| Clang Xcode 6.2 | Darwin Kernel Version 13.4.0 | Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn) |
| Clang Xcode 6.3 | Darwin Kernel Version 14.3.0 | Apple LLVM version 6.1.0 (clang-602.0.49) (based on LLVM 3.6.0svn) |
| Clang Xcode 6.4 | Darwin Kernel Version 14.3.0 | Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn) |
| Clang Xcode 7.1 | Darwin Kernel Version 14.5.0 | Apple LLVM version 7.0.0 (clang-700.1.76) |
| Clang Xcode 7.2 | Darwin Kernel Version 15.0.0 | Apple LLVM version 7.0.2 (clang-700.1.81) |
| Clang Xcode 7.3 | Darwin Kernel Version 14.5.0 | Apple LLVM version 7.3.0 (clang-703.0.29) |
| Visual Studio 14 2015 | Windows Server 2012 R2 (x64) | Microsoft (R) Build Engine version 14.0.25123.0 |
## Examples
Here are some examples to give you an idea how to use the class.
@ -428,7 +449,7 @@ $ make
$ ./json_unit "*"
===============================================================================
All tests passed (3344416 assertions in 30 test cases)
All tests passed (5568703 assertions in 31 test cases)
```
For more information, have a look at the file [.travis.yml](https://github.com/nlohmann/json/blob/master/.travis.yml).

34
doc/examples/diff.cpp Normal file
View file

@ -0,0 +1,34 @@
#include <json.hpp>
using json = nlohmann::json;
int main()
{
// the source document
json source = R"(
{
"baz": "qux",
"foo": "bar"
}
)"_json;
// the target document
json target = R"(
{
"baz": "boo",
"hello": [
"world"
]
}
)"_json;
// create the patch
json patch = json::diff(source, target);
// roundtrip
json patched_source = source.patch(patch);
// output patch and roundtrip result
std::cout << std::setw(4) << patch << "\n\n"
<< std::setw(4) << patched_source << std::endl;
}

1
doc/examples/diff.link Normal file
View file

@ -0,0 +1 @@
<a target="_blank" href="http://melpon.org/wandbox/permlink/hicmeOK39tBxaluM"><b>online</b></a>

25
doc/examples/diff.output Normal file
View file

@ -0,0 +1,25 @@
[
{
"op": "replace",
"path": "/baz",
"value": "boo"
},
{
"op": "remove",
"path": "/foo"
},
{
"op": "add",
"path": "/hello",
"value": [
"world"
]
}
]
{
"baz": "boo",
"hello": [
"world"
]
}

9
doc/examples/flatten.cpp
View file

@ -20,18 +20,11 @@ int main()
{
"object", {
{"currency", "USD"},
{"value", 42.99},
{"", "empty string"},
{"/", "slash"},
{"~", "tilde"},
{"~1", "tilde1"}
{"value", 42.99}
}
}
};
// call flatten()
std::cout << std::setw(4) << j.flatten() << '\n';
// flatten for a primitive value
std::cout << j["pi"].flatten() << '\n';
}

2
doc/examples/flatten.link
View file

@ -1 +1 @@
<a target="_blank" href="http://melpon.org/wandbox/permlink/skGi8b32VhI8HOgV"><b>online</b></a>
<a target="_blank" href="http://melpon.org/wandbox/permlink/OZG9sHcJCXsScNiy"><b>online</b></a>

5
doc/examples/flatten.output
View file

@ -6,12 +6,7 @@
"/list/2": 2,
"/name": "Niels",
"/nothing": null,
"/object/": "empty string",
"/object/currency": "USD",
"/object/value": 42.99,
"/object/~0": "tilde",
"/object/~01": "tilde1",
"/object/~1": "slash",
"/pi": 3.141
}
{"":3.141}

34
doc/examples/json_pointer__to_string.cpp Normal file
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@ -0,0 +1,34 @@
#include <json.hpp>
using json = nlohmann::json;
int main()
{
// different JSON Pointers
json::json_pointer ptr1("");
json::json_pointer ptr2("/foo");
json::json_pointer ptr3("/foo/0");
json::json_pointer ptr4("/");
json::json_pointer ptr5("/a~1b");
json::json_pointer ptr6("/c%d");
json::json_pointer ptr7("/e^f");
json::json_pointer ptr8("/g|h");
json::json_pointer ptr9("/i\\j");
json::json_pointer ptr10("/k\"l");
json::json_pointer ptr11("/ ");
json::json_pointer ptr12("/m~0n");
std::cout << ptr1.to_string() << '\n'
<< ptr2.to_string() << '\n'
<< ptr3.to_string() << '\n'
<< ptr4.to_string() << '\n'
<< ptr5.to_string() << '\n'
<< ptr6.to_string() << '\n'
<< ptr7.to_string() << '\n'
<< ptr8.to_string() << '\n'
<< ptr9.to_string() << '\n'
<< ptr10.to_string() << '\n'
<< ptr11.to_string() << '\n'
<< ptr12.to_string() << std::endl;
}

1
doc/examples/json_pointer__to_string.link Normal file
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@ -0,0 +1 @@
<a target="_blank" href="http://melpon.org/wandbox/permlink/O4FbKx0TbZioFhfU"><b>online</b></a>

12
doc/examples/json_pointer__to_string.output Normal file
View file

@ -0,0 +1,12 @@
/foo
/foo/0
/
/a~1b
/c%d
/e^f
/g|h
/i\j
/k"l
/
/m~0n

30
doc/examples/patch.cpp Normal file
View file

@ -0,0 +1,30 @@
#include <json.hpp>
using json = nlohmann::json;
int main()
{
// the original document
json doc = R"(
{
"baz": "qux",
"foo": "bar"
}
)"_json;
// the patch
json patch = R"(
[
{ "op": "replace", "path": "/baz", "value": "boo" },
{ "op": "add", "path": "/hello", "value": ["world"] },
{ "op": "remove", "path": "/foo"}
]
)"_json;
// apply the patch
json patched_doc = doc.patch(patch);
// output original and patched document
std::cout << std::setw(4) << doc << "\n\n"
<< std::setw(4) << patched_doc << std::endl;
}

1
doc/examples/patch.link Normal file
View file

@ -0,0 +1 @@
<a target="_blank" href="http://melpon.org/wandbox/permlink/lbczW3AzcUbH1Nbo"><b>online</b></a>

11
doc/examples/patch.output Normal file
View file

@ -0,0 +1,11 @@
{
"baz": "qux",
"foo": "bar"
}
{
"baz": "boo",
"hello": [
"world"
]
}

4
doc/examples/unflatten.cpp
View file

@ -14,12 +14,8 @@ int main()
{"/list/2", 2},
{"/name", "Niels"},
{"/nothing", nullptr},
{"/object/", "empty string"},
{"/object/currency", "USD"},
{"/object/value", 42.99},
{"/object/~0", "tilde"},
{"/object/~01", "tilde1"},
{"/object/~1", "slash"},
{"/pi", 3.141}
};

2
doc/examples/unflatten.link
View file

@ -1 +1 @@
<a target="_blank" href="http://melpon.org/wandbox/permlink/ITqCZsXmi0I7KGYy"><b>online</b></a>
<a target="_blank" href="http://melpon.org/wandbox/permlink/m2UmItixDxnYs1Se"><b>online</b></a>

6
doc/examples/unflatten.output
View file

@ -11,12 +11,8 @@
"name": "Niels",
"nothing": null,
"object": {
"": "empty string",
"/": "slash",
"currency": "USD",
"value": 42.99,
"~": "tilde",
"~1": "tilde1"
"value": 42.99
},
"pi": 3.141
}

828
src/json.hpp
View file

@ -3595,121 +3595,6 @@ class basic_json
}
}
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. Similar to
@ref operator[](const typename object_t::key_type&), `null` values
are created in arrays and objects if necessary.
In particular:
- If the JSON pointer points to an object key that does not exist, it
is created an filled with a `null` value before a reference to it
is returned.
- If the JSON pointer points to an array index that does not exist, it
is created an filled with a `null` value before a reference to it
is returned. All indices between the current maximum and the given
index are also filled with `null`.
- The special value `-` is treated as a synonym for the index past the
end.
@param[in] ptr a JSON pointer
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer}
@since version 2.0.0
*/
reference operator[](const json_pointer& ptr)
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. The function does not change the JSON
value; no `null` values are created. In particular, the the special value
`-` yields an exception.
@param[in] ptr JSON pointer to the desired element
@return const reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
@since version 2.0.0
*/
const_reference operator[](const json_pointer& ptr) const
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a reference to the element at with specified JSON pointer @a ptr,
with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer}
@since version 2.0.0
*/
reference at(const json_pointer& ptr)
{
return ptr.get_checked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a const reference to the element at with specified JSON pointer
@a ptr, with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer_const}
@since version 2.0.0
*/
const_reference at(const json_pointer& ptr) const
{
return ptr.get_checked(this);
}
/*!
@brief access specified object element with default value
@ -4145,8 +4030,8 @@ class basic_json
@throw std::domain_error when called on a type other than JSON array;
example: `"cannot use erase() with null"`
@throw std::out_of_range when `idx >= size()`; example: `"index out of
range"`
@throw std::out_of_range when `idx >= size()`; example: `"array index 17
is out of range"`
@complexity Linear in distance between @a idx and the end of the container.
@ -4167,7 +4052,7 @@ class basic_json
{
if (idx >= size())
{
throw std::out_of_range("index out of range");
throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
}
assert(m_value.array != nullptr);
@ -8933,6 +8818,10 @@ basic_json_parser_63:
/*!
@brief JSON Pointer
A JSON pointer defines a string syntax for identifying a specific value
within a JSON document. It can be used with functions `at` and
`operator[]`. Furthermore, JSON pointers are the base for JSON patches.
@sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
@since version 2.0.0
@ -8969,7 +8858,71 @@ basic_json_parser_63:
: reference_tokens(split(s))
{}
/*!
@brief return a string representation of the JSON pointer
@invariant For each JSON pointer `ptr`, it holds:
@code {.cpp}
ptr == json_pointer(ptr.to_string());
@endcode
@return a string representation of the JSON pointer
@liveexample{The example shows the result of `to_string`.,
json_pointer__to_string}
@since version 2.0.0
*/
std::string to_string() const noexcept
{
std::string result;
for (const auto& reference_token : reference_tokens)
{
result += "/" + escape(reference_token);
}
return result;
}
/// @copydoc to_string()
operator std::string() const
{
return to_string();
}
private:
/// remove and return last reference pointer
std::string pop_back()
{
if (is_root())
{
throw std::domain_error("JSON pointer has no parent");
}
auto last = reference_tokens.back();
reference_tokens.pop_back();
return last;
}
/// return whether pointer points to the root document
bool is_root() const
{
return reference_tokens.empty();
}
json_pointer top() const
{
if (is_root())
{
throw std::domain_error("JSON pointer has no parent");
}
json_pointer result = *this;
result.reference_tokens = {reference_tokens[0]};
return result;
}
/*!
@brief create and return a reference to the pointed to value
*/
@ -9008,7 +8961,7 @@ basic_json_parser_63:
case value_t::array:
{
// create an entry in the array
result = &result->operator[](static_cast<size_t>(std::stoi(reference_token)));
result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -9071,7 +9024,7 @@ basic_json_parser_63:
else
{
// convert array index to number; unchecked access
ptr = &ptr->operator[](static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
}
break;
}
@ -9116,7 +9069,7 @@ basic_json_parser_63:
}
// note: at performs range check
ptr = &ptr->at(static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -9168,7 +9121,7 @@ basic_json_parser_63:
}
// use unchecked array access
ptr = &ptr->operator[](static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -9212,7 +9165,7 @@ basic_json_parser_63:
}
// note: at performs range check
ptr = &ptr->at(static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -9279,12 +9232,8 @@ basic_json_parser_63:
}
}
// first transform any occurrence of the sequence '~1' to '/'
replace_substring(reference_token, "~1", "/");
// then transform any occurrence of the sequence '~0' to '~'
replace_substring(reference_token, "~0", "~");
// finally, store the reference token
unescape(reference_token);
result.push_back(reference_token);
}
@ -9320,6 +9269,24 @@ basic_json_parser_63:
);
}
/// escape tilde and slash
static std::string escape(std::string s)
{
// escape "~"" to "~0" and "/" to "~1"
replace_substring(s, "~", "~0");
replace_substring(s, "/", "~1");
return s;
}
/// unescape tilde and slash
static void unescape(std::string& s)
{
// first transform any occurrence of the sequence '~1' to '/'
replace_substring(s, "~1", "/");
// then transform any occurrence of the sequence '~0' to '~'
replace_substring(s, "~0", "~");
}
/*!
@param[in] reference_string the reference string to the current value
@param[in] value the value to consider
@ -9327,7 +9294,7 @@ basic_json_parser_63:
@note Empty objects or arrays are flattened to `null`.
*/
static void flatten(const std::string reference_string,
static void flatten(const std::string& reference_string,
const basic_json& value,
basic_json& result)
{
@ -9364,12 +9331,7 @@ basic_json_parser_63:
// iterate object and use keys as reference string
for (const auto& element : *value.m_value.object)
{
// escape "~"" to "~0" and "/" to "~1"
std::string key(element.first);
replace_substring(key, "~", "~0");
replace_substring(key, "/", "~1");
flatten(reference_string + "/" + key,
flatten(reference_string + "/" + escape(element.first),
element.second, result);
}
}
@ -9420,16 +9382,131 @@ basic_json_parser_63:
private:
/// the reference tokens
const std::vector<std::string> reference_tokens {};
std::vector<std::string> reference_tokens {};
};
////////////////////////////
// JSON Pointer functions //
////////////////////////////
//////////////////////////
// JSON Pointer support //
//////////////////////////
/// @name JSON Pointer functions
/// @{
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. Similar to
@ref operator[](const typename object_t::key_type&), `null` values
are created in arrays and objects if necessary.
In particular:
- If the JSON pointer points to an object key that does not exist, it
is created an filled with a `null` value before a reference to it
is returned.
- If the JSON pointer points to an array index that does not exist, it
is created an filled with a `null` value before a reference to it
is returned. All indices between the current maximum and the given
index are also filled with `null`.
- The special value `-` is treated as a synonym for the index past the
end.
@param[in] ptr a JSON pointer
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer}
@since version 2.0.0
*/
reference operator[](const json_pointer& ptr)
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. The function does not change the JSON
value; no `null` values are created. In particular, the the special value
`-` yields an exception.
@param[in] ptr JSON pointer to the desired element
@return const reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
@since version 2.0.0
*/
const_reference operator[](const json_pointer& ptr) const
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a reference to the element at with specified JSON pointer @a ptr,
with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer}
@since version 2.0.0
*/
reference at(const json_pointer& ptr)
{
return ptr.get_checked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a const reference to the element at with specified JSON pointer
@a ptr, with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer_const}
@since version 2.0.0
*/
const_reference at(const json_pointer& ptr) const
{
return ptr.get_checked(this);
}
/*!
@brief return flattened JSON value
@ -9492,6 +9569,473 @@ basic_json_parser_63:
}
/// @}
//////////////////////////
// JSON Patch functions //
//////////////////////////
/// @name JSON Patch functions
/// @{
/*!
@brief applies a JSON patch
[JSON Patch](http://jsonpatch.com) defines a JSON document structure for
expressing a sequence of operations to apply to a JSON) document. With
this funcion, a JSON Patch is applied to the current JSON value by
executing all operations from the patch.
@param[in] patch JSON patch document
@return patched document
@note The application of a patch is atomic: Either all operations succeed
and the patched document is returned or an exception is thrown. In
any case, the original value is not changed: the patch is applied
to a copy of the value.
@throw std::out_of_range if a JSON pointer inside the patch could not
be resolved successfully in the current JSON value; example: `"key baz
not found"`
@throw invalid_argument if the JSON patch is malformed (e.g., mandatory
attributes are missing); example: `"operation add must have member path"`
@complexity Linear in the size of the JSON value and the length of the
JSON patch. As usually only a fraction of the JSON value is affected by
the patch, the complexity can usually be neglected.
@liveexample{The following code shows how a JSON patch is applied to a
value.,patch}
@sa @ref diff -- create a JSON patch by comparing two JSON values
@sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
@sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
@since version 2.0.0
*/
basic_json patch(const basic_json& patch) const
{
// make a working copy to apply the patch to
basic_json result = *this;
// the valid JSON Patch operations
enum class patch_operations {add, remove, replace, move, copy, test, invalid};
const auto get_op = [](const std::string op)
{
if (op == "add")
{
return patch_operations::add;
}
if (op == "remove")
{
return patch_operations::remove;
}
if (op == "replace")
{
return patch_operations::replace;
}
if (op == "move")
{
return patch_operations::move;
}
if (op == "copy")
{
return patch_operations::copy;
}
if (op == "test")
{
return patch_operations::test;
}
return patch_operations::invalid;
};
// wrapper for "add" operation; add value at ptr
const auto operation_add = [&result](json_pointer & ptr, basic_json val)
{
// adding to the root of the target document means replacing it
if (ptr.is_root())
{
result = val;
}
else
{
// make sure the top element of the pointer exists
json_pointer top_pointer = ptr.top();
if (top_pointer != ptr)
{
basic_json& x = result.at(top_pointer);
}
// get reference to parent of JSON pointer ptr
const auto last_path = ptr.pop_back();
basic_json& parent = result[ptr];
switch (parent.m_type)
{
case value_t::null:
case value_t::object:
{
// use operator[] to add value
parent[last_path] = val;
break;
}
case value_t::array:
{
if (last_path == "-")
{
// special case: append to back
parent.push_back(val);
}
else
{
const auto idx = std::stoi(last_path);
if (static_cast<size_type>(idx) > parent.size())
{
// avoid undefined behavior
throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
}
else
{
// default case: insert add offset
parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
}
}
break;
}
default:
{
// if there exists a parent it cannot be primitive
assert(false); // LCOV_EXCL_LINE
}
}
}
};
// wrapper for "remove" operation; remove value at ptr
const auto operation_remove = [&result](json_pointer & ptr)
{
// get reference to parent of JSON pointer ptr
const auto last_path = ptr.pop_back();
basic_json& parent = result.at(ptr);
// remove child
if (parent.is_object())
{
// perform range check
auto it = parent.find(last_path);
if (it != parent.end())
{
parent.erase(it);
}
else
{
throw std::out_of_range("key '" + last_path + "' not found");
}
}
else if (parent.is_array())
{
// note erase performs range check
parent.erase(static_cast<size_type>(std::stoi(last_path)));
}
};
// type check
if (not patch.is_array())
{
// a JSON patch must be an array of objects
throw std::invalid_argument("JSON patch must be an array of objects");
}
// iterate and apply th eoperations
for (const auto& val : patch)
{
// wrapper to get a value for an operation
const auto get_value = [&val](const std::string & op,
const std::string & member,
bool string_type) -> basic_json&
{
// find value
auto it = val.m_value.object->find(member);
// context-sensitive error message
const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
// check if desired value is present
if (it == val.m_value.object->end())
{
throw std::invalid_argument(error_msg + " must have member '" + member + "'");
}
// check if result is of type string
if (string_type and not it->second.is_string())
{
throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
}
// no error: return value
return it->second;
};
// type check
if (not val.is_object())
{
throw std::invalid_argument("JSON patch must be an array of objects");
}
// collect mandatory members
const std::string op = get_value("op", "op", true);
const std::string path = get_value(op, "path", true);
json_pointer ptr(path);
switch (get_op(op))
{
case patch_operations::add:
{
operation_add(ptr, get_value("add", "value", false));
break;
}
case patch_operations::remove:
{
operation_remove(ptr);
break;
}
case patch_operations::replace:
{
// the "path" location must exist - use at()
result.at(ptr) = get_value("replace", "value", false);
break;
}
case patch_operations::move:
{
const std::string from_path = get_value("move", "from", true);
json_pointer from_ptr(from_path);
// the "from" location must exist - use at()
basic_json v = result.at(from_ptr);
// The move operation is functionally identical to a
// "remove" operation on the "from" location, followed
// immediately by an "add" operation at the target
// location with the value that was just removed.
operation_remove(from_ptr);
operation_add(ptr, v);
break;
}
case patch_operations::copy:
{
const std::string from_path = get_value("copy", "from", true);;
const json_pointer from_ptr(from_path);
// the "from" location must exist - use at()
result[ptr] = result.at(from_ptr);
break;
}
case patch_operations::test:
{
bool success = false;
try
{
// check if "value" matches the one at "path"
// the "path" location must exist - use at()
success = (result.at(ptr) == get_value("test", "value", false));
}
catch (std::out_of_range&)
{
// ignore out of range errors: success remains false
}
// throw an exception if test fails
if (not success)
{
throw std::domain_error("unsuccessful: " + val.dump());
}
break;
}
case patch_operations::invalid:
{
// op must be "add", "remove", "replace", "move", "copy", or
// "test"
throw std::invalid_argument("operation value '" + op + "' is invalid");
}
}
}
return result;
}
/*!
@brief creates a diff as a JSON patch
Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can
be changed into the value @a target by calling @ref patch function.
@invariant For two JSON values @a source and @a target, the following code
yields always `true`:
@code {.cpp}
source.patch(diff(source, target)) == target;
@endcode
@note Currently, only `remove`, `add`, and `replace` operations are
generated.
@param[in] source JSON value to copare from
@param[in] target JSON value to copare against
@param[in] path helper value to create JSON pointers
@return a JSON patch to convert the @a source to @a target
@complexity Linear in the lengths of @a source and @a target.
@liveexample{The following code shows how a JSON patch is created as a
diff for two JSON values.,diff}
@sa @ref patch -- apply a JSON patch
@sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
@since version 2.0.0
*/
static basic_json diff(const basic_json& source,
const basic_json& target,
std::string path = "") noexcept
{
// the patch
basic_json result(value_t::array);
// if the values are the same, return empty patch
if (source == target)
{
return result;
}
if (source.type() != target.type())
{
// different types: replace value
result.push_back(
{
{"op", "replace"},
{"path", path},
{"value", target}
});
}
else
{
switch (source.type())
{
case value_t::array:
{
// first pass: traverse common elements
size_t i = 0;
while (i < source.size() and i < target.size())
{
// recursive call to compare array values at index i
auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
result.insert(result.end(), temp_diff.begin(), temp_diff.end());
++i;
}
// i now reached the end of at least one array
// in a second pass, traverse the remaining elements
// remove my remaining elements
while (i < source.size())
{
result.push_back(object(
{
{"op", "remove"},
{"path", path + "/" + std::to_string(i)}
}));
++i;
}
// add other remaining elements
while (i < target.size())
{
result.push_back(
{
{"op", "add"},
{"path", path + "/" + std::to_string(i)},
{"value", target[i]}
});
++i;
}
break;
}
case value_t::object:
{
// first pass: traverse this object's elements
for (auto it = source.begin(); it != source.end(); ++it)
{
// escape the key name to be used in a JSON patch
const auto key = json_pointer::escape(it.key());
if (target.find(it.key()) != target.end())
{
// recursive call to compare object values at key it
auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
result.insert(result.end(), temp_diff.begin(), temp_diff.end());
}
else
{
// found a key that is not in o -> remove it
result.push_back(object(
{
{"op", "remove"},
{"path", path + "/" + key}
}));
}
}
// second pass: traverse other object's elements
for (auto it = target.begin(); it != target.end(); ++it)
{
if (source.find(it.key()) == source.end())
{
// found a key that is not in this -> add it
const auto key = json_pointer::escape(it.key());
result.push_back(
{
{"op", "add"},
{"path", path + "/" + key},
{"value", it.value()}
});
}
}
break;
}
default:
{
// both primitive type: replace value
result.push_back(
{
{"op", "replace"},
{"path", path},
{"value", target}
});
break;
}
}
}
return result;
}
/// @}
};
@ -9511,9 +10055,9 @@ using json = basic_json<>;
}
/////////////////////////
// nonmember functions //
/////////////////////////
///////////////////////
// nonmember support //
///////////////////////
// specialization of std::swap, and std::hash
namespace std

828
src/json.hpp.re2c
View file

@ -3595,121 +3595,6 @@ class basic_json
}
}
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. Similar to
@ref operator[](const typename object_t::key_type&), `null` values
are created in arrays and objects if necessary.
In particular:
- If the JSON pointer points to an object key that does not exist, it
is created an filled with a `null` value before a reference to it
is returned.
- If the JSON pointer points to an array index that does not exist, it
is created an filled with a `null` value before a reference to it
is returned. All indices between the current maximum and the given
index are also filled with `null`.
- The special value `-` is treated as a synonym for the index past the
end.
@param[in] ptr a JSON pointer
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer}
@since version 2.0.0
*/
reference operator[](const json_pointer& ptr)
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. The function does not change the JSON
value; no `null` values are created. In particular, the the special value
`-` yields an exception.
@param[in] ptr JSON pointer to the desired element
@return const reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
@since version 2.0.0
*/
const_reference operator[](const json_pointer& ptr) const
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a reference to the element at with specified JSON pointer @a ptr,
with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer}
@since version 2.0.0
*/
reference at(const json_pointer& ptr)
{
return ptr.get_checked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a const reference to the element at with specified JSON pointer
@a ptr, with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer_const}
@since version 2.0.0
*/
const_reference at(const json_pointer& ptr) const
{
return ptr.get_checked(this);
}
/*!
@brief access specified object element with default value
@ -4145,8 +4030,8 @@ class basic_json
@throw std::domain_error when called on a type other than JSON array;
example: `"cannot use erase() with null"`
@throw std::out_of_range when `idx >= size()`; example: `"index out of
range"`
@throw std::out_of_range when `idx >= size()`; example: `"array index 17
is out of range"`
@complexity Linear in distance between @a idx and the end of the container.
@ -4167,7 +4052,7 @@ class basic_json
{
if (idx >= size())
{
throw std::out_of_range("index out of range");
throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
}
assert(m_value.array != nullptr);
@ -8243,6 +8128,10 @@ class basic_json
/*!
@brief JSON Pointer
A JSON pointer defines a string syntax for identifying a specific value
within a JSON document. It can be used with functions `at` and
`operator[]`. Furthermore, JSON pointers are the base for JSON patches.
@sa [RFC 6901](https://tools.ietf.org/html/rfc6901)
@since version 2.0.0
@ -8279,7 +8168,71 @@ class basic_json
: reference_tokens(split(s))
{}
/*!
@brief return a string representation of the JSON pointer
@invariant For each JSON pointer `ptr`, it holds:
@code {.cpp}
ptr == json_pointer(ptr.to_string());
@endcode
@return a string representation of the JSON pointer
@liveexample{The example shows the result of `to_string`.,
json_pointer__to_string}
@since version 2.0.0
*/
std::string to_string() const noexcept
{
std::string result;
for (const auto& reference_token : reference_tokens)
{
result += "/" + escape(reference_token);
}
return result;
}
/// @copydoc to_string()
operator std::string() const
{
return to_string();
}
private:
/// remove and return last reference pointer
std::string pop_back()
{
if (is_root())
{
throw std::domain_error("JSON pointer has no parent");
}
auto last = reference_tokens.back();
reference_tokens.pop_back();
return last;
}
/// return whether pointer points to the root document
bool is_root() const
{
return reference_tokens.empty();
}
json_pointer top() const
{
if (is_root())
{
throw std::domain_error("JSON pointer has no parent");
}
json_pointer result = *this;
result.reference_tokens = {reference_tokens[0]};
return result;
}
/*!
@brief create and return a reference to the pointed to value
*/
@ -8318,7 +8271,7 @@ class basic_json
case value_t::array:
{
// create an entry in the array
result = &result->operator[](static_cast<size_t>(std::stoi(reference_token)));
result = &result->operator[](static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -8381,7 +8334,7 @@ class basic_json
else
{
// convert array index to number; unchecked access
ptr = &ptr->operator[](static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
}
break;
}
@ -8426,7 +8379,7 @@ class basic_json
}
// note: at performs range check
ptr = &ptr->at(static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -8478,7 +8431,7 @@ class basic_json
}
// use unchecked array access
ptr = &ptr->operator[](static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->operator[](static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -8522,7 +8475,7 @@ class basic_json
}
// note: at performs range check
ptr = &ptr->at(static_cast<size_t>(std::stoi(reference_token)));
ptr = &ptr->at(static_cast<size_type>(std::stoi(reference_token)));
break;
}
@ -8589,12 +8542,8 @@ class basic_json
}
}
// first transform any occurrence of the sequence '~1' to '/'
replace_substring(reference_token, "~1", "/");
// then transform any occurrence of the sequence '~0' to '~'
replace_substring(reference_token, "~0", "~");
// finally, store the reference token
unescape(reference_token);
result.push_back(reference_token);
}
@ -8630,6 +8579,24 @@ class basic_json
);
}
/// escape tilde and slash
static std::string escape(std::string s)
{
// escape "~"" to "~0" and "/" to "~1"
replace_substring(s, "~", "~0");
replace_substring(s, "/", "~1");
return s;
}
/// unescape tilde and slash
static void unescape(std::string& s)
{
// first transform any occurrence of the sequence '~1' to '/'
replace_substring(s, "~1", "/");
// then transform any occurrence of the sequence '~0' to '~'
replace_substring(s, "~0", "~");
}
/*!
@param[in] reference_string the reference string to the current value
@param[in] value the value to consider
@ -8637,7 +8604,7 @@ class basic_json
@note Empty objects or arrays are flattened to `null`.
*/
static void flatten(const std::string reference_string,
static void flatten(const std::string& reference_string,
const basic_json& value,
basic_json& result)
{
@ -8674,12 +8641,7 @@ class basic_json
// iterate object and use keys as reference string
for (const auto& element : *value.m_value.object)
{
// escape "~"" to "~0" and "/" to "~1"
std::string key(element.first);
replace_substring(key, "~", "~0");
replace_substring(key, "/", "~1");
flatten(reference_string + "/" + key,
flatten(reference_string + "/" + escape(element.first),
element.second, result);
}
}
@ -8730,16 +8692,131 @@ class basic_json
private:
/// the reference tokens
const std::vector<std::string> reference_tokens {};
std::vector<std::string> reference_tokens {};
};
////////////////////////////
// JSON Pointer functions //
////////////////////////////
//////////////////////////
// JSON Pointer support //
//////////////////////////
/// @name JSON Pointer functions
/// @{
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. Similar to
@ref operator[](const typename object_t::key_type&), `null` values
are created in arrays and objects if necessary.
In particular:
- If the JSON pointer points to an object key that does not exist, it
is created an filled with a `null` value before a reference to it
is returned.
- If the JSON pointer points to an array index that does not exist, it
is created an filled with a `null` value before a reference to it
is returned. All indices between the current maximum and the given
index are also filled with `null`.
- The special value `-` is treated as a synonym for the index past the
end.
@param[in] ptr a JSON pointer
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer}
@since version 2.0.0
*/
reference operator[](const json_pointer& ptr)
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Uses a JSON pointer to retrieve a reference to the respective JSON value.
No bound checking is performed. The function does not change the JSON
value; no `null` values are created. In particular, the the special value
`-` yields an exception.
@param[in] ptr JSON pointer to the desired element
@return const reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,operatorjson_pointer_const}
@since version 2.0.0
*/
const_reference operator[](const json_pointer& ptr) const
{
return ptr.get_unchecked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a reference to the element at with specified JSON pointer @a ptr,
with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer}
@since version 2.0.0
*/
reference at(const json_pointer& ptr)
{
return ptr.get_checked(this);
}
/*!
@brief access specified element via JSON Pointer
Returns a const reference to the element at with specified JSON pointer
@a ptr, with bounds checking.
@param[in] ptr JSON pointer to the desired element
@return reference to the element pointed to by @a ptr
@complexity Constant.
@throw std::out_of_range if the JSON pointer can not be resolved
@throw std::domain_error if an array index begins with '0'
@throw std::invalid_argument if an array index was not a number
@liveexample{The behavior is shown in the example.,at_json_pointer_const}
@since version 2.0.0
*/
const_reference at(const json_pointer& ptr) const
{
return ptr.get_checked(this);
}
/*!
@brief return flattened JSON value
@ -8802,6 +8879,473 @@ class basic_json
}
/// @}
//////////////////////////
// JSON Patch functions //
//////////////////////////
/// @name JSON Patch functions
/// @{
/*!
@brief applies a JSON patch
[JSON Patch](http://jsonpatch.com) defines a JSON document structure for
expressing a sequence of operations to apply to a JSON) document. With
this funcion, a JSON Patch is applied to the current JSON value by
executing all operations from the patch.
@param[in] patch JSON patch document
@return patched document
@note The application of a patch is atomic: Either all operations succeed
and the patched document is returned or an exception is thrown. In
any case, the original value is not changed: the patch is applied
to a copy of the value.
@throw std::out_of_range if a JSON pointer inside the patch could not
be resolved successfully in the current JSON value; example: `"key baz
not found"`
@throw invalid_argument if the JSON patch is malformed (e.g., mandatory
attributes are missing); example: `"operation add must have member path"`
@complexity Linear in the size of the JSON value and the length of the
JSON patch. As usually only a fraction of the JSON value is affected by
the patch, the complexity can usually be neglected.
@liveexample{The following code shows how a JSON patch is applied to a
value.,patch}
@sa @ref diff -- create a JSON patch by comparing two JSON values
@sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
@sa [RFC 6901 (JSON Pointer)](https://tools.ietf.org/html/rfc6901)
@since version 2.0.0
*/
basic_json patch(const basic_json& patch) const
{
// make a working copy to apply the patch to
basic_json result = *this;
// the valid JSON Patch operations
enum class patch_operations {add, remove, replace, move, copy, test, invalid};
const auto get_op = [](const std::string op)
{
if (op == "add")
{
return patch_operations::add;
}
if (op == "remove")
{
return patch_operations::remove;
}
if (op == "replace")
{
return patch_operations::replace;
}
if (op == "move")
{
return patch_operations::move;
}
if (op == "copy")
{
return patch_operations::copy;
}
if (op == "test")
{
return patch_operations::test;
}
return patch_operations::invalid;
};
// wrapper for "add" operation; add value at ptr
const auto operation_add = [&result](json_pointer & ptr, basic_json val)
{
// adding to the root of the target document means replacing it
if (ptr.is_root())
{
result = val;
}
else
{
// make sure the top element of the pointer exists
json_pointer top_pointer = ptr.top();
if (top_pointer != ptr)
{
basic_json& x = result.at(top_pointer);
}
// get reference to parent of JSON pointer ptr
const auto last_path = ptr.pop_back();
basic_json& parent = result[ptr];
switch (parent.m_type)
{
case value_t::null:
case value_t::object:
{
// use operator[] to add value
parent[last_path] = val;
break;
}
case value_t::array:
{
if (last_path == "-")
{
// special case: append to back
parent.push_back(val);
}
else
{
const auto idx = std::stoi(last_path);
if (static_cast<size_type>(idx) > parent.size())
{
// avoid undefined behavior
throw std::out_of_range("array index " + std::to_string(idx) + " is out of range");
}
else
{
// default case: insert add offset
parent.insert(parent.begin() + static_cast<difference_type>(idx), val);
}
}
break;
}
default:
{
// if there exists a parent it cannot be primitive
assert(false); // LCOV_EXCL_LINE
}
}
}
};
// wrapper for "remove" operation; remove value at ptr
const auto operation_remove = [&result](json_pointer & ptr)
{
// get reference to parent of JSON pointer ptr
const auto last_path = ptr.pop_back();
basic_json& parent = result.at(ptr);
// remove child
if (parent.is_object())
{
// perform range check
auto it = parent.find(last_path);
if (it != parent.end())
{
parent.erase(it);
}
else
{
throw std::out_of_range("key '" + last_path + "' not found");
}
}
else if (parent.is_array())
{
// note erase performs range check
parent.erase(static_cast<size_type>(std::stoi(last_path)));
}
};
// type check
if (not patch.is_array())
{
// a JSON patch must be an array of objects
throw std::invalid_argument("JSON patch must be an array of objects");
}
// iterate and apply th eoperations
for (const auto& val : patch)
{
// wrapper to get a value for an operation
const auto get_value = [&val](const std::string & op,
const std::string & member,
bool string_type) -> basic_json&
{
// find value
auto it = val.m_value.object->find(member);
// context-sensitive error message
const auto error_msg = (op == "op") ? "operation" : "operation '" + op + "'";
// check if desired value is present
if (it == val.m_value.object->end())
{
throw std::invalid_argument(error_msg + " must have member '" + member + "'");
}
// check if result is of type string
if (string_type and not it->second.is_string())
{
throw std::invalid_argument(error_msg + " must have string member '" + member + "'");
}
// no error: return value
return it->second;
};
// type check
if (not val.is_object())
{
throw std::invalid_argument("JSON patch must be an array of objects");
}
// collect mandatory members
const std::string op = get_value("op", "op", true);
const std::string path = get_value(op, "path", true);
json_pointer ptr(path);
switch (get_op(op))
{
case patch_operations::add:
{
operation_add(ptr, get_value("add", "value", false));
break;
}
case patch_operations::remove:
{
operation_remove(ptr);
break;
}
case patch_operations::replace:
{
// the "path" location must exist - use at()
result.at(ptr) = get_value("replace", "value", false);
break;
}
case patch_operations::move:
{
const std::string from_path = get_value("move", "from", true);
json_pointer from_ptr(from_path);
// the "from" location must exist - use at()
basic_json v = result.at(from_ptr);
// The move operation is functionally identical to a
// "remove" operation on the "from" location, followed
// immediately by an "add" operation at the target
// location with the value that was just removed.
operation_remove(from_ptr);
operation_add(ptr, v);
break;
}
case patch_operations::copy:
{
const std::string from_path = get_value("copy", "from", true);;
const json_pointer from_ptr(from_path);
// the "from" location must exist - use at()
result[ptr] = result.at(from_ptr);
break;
}
case patch_operations::test:
{
bool success = false;
try
{
// check if "value" matches the one at "path"
// the "path" location must exist - use at()
success = (result.at(ptr) == get_value("test", "value", false));
}
catch (std::out_of_range&)
{
// ignore out of range errors: success remains false
}
// throw an exception if test fails
if (not success)
{
throw std::domain_error("unsuccessful: " + val.dump());
}
break;
}
case patch_operations::invalid:
{
// op must be "add", "remove", "replace", "move", "copy", or
// "test"
throw std::invalid_argument("operation value '" + op + "' is invalid");
}
}
}
return result;
}
/*!
@brief creates a diff as a JSON patch
Creates a [JSON Patch](http://jsonpatch.com) so that value @a source can
be changed into the value @a target by calling @ref patch function.
@invariant For two JSON values @a source and @a target, the following code
yields always `true`:
@code {.cpp}
source.patch(diff(source, target)) == target;
@endcode
@note Currently, only `remove`, `add`, and `replace` operations are
generated.
@param[in] source JSON value to copare from
@param[in] target JSON value to copare against
@param[in] path helper value to create JSON pointers
@return a JSON patch to convert the @a source to @a target
@complexity Linear in the lengths of @a source and @a target.
@liveexample{The following code shows how a JSON patch is created as a
diff for two JSON values.,diff}
@sa @ref patch -- apply a JSON patch
@sa [RFC 6902 (JSON Patch)](https://tools.ietf.org/html/rfc6902)
@since version 2.0.0
*/
static basic_json diff(const basic_json& source,
const basic_json& target,
std::string path = "") noexcept
{
// the patch
basic_json result(value_t::array);
// if the values are the same, return empty patch
if (source == target)
{
return result;
}
if (source.type() != target.type())
{
// different types: replace value
result.push_back(
{
{"op", "replace"},
{"path", path},
{"value", target}
});
}
else
{
switch (source.type())
{
case value_t::array:
{
// first pass: traverse common elements
size_t i = 0;
while (i < source.size() and i < target.size())
{
// recursive call to compare array values at index i
auto temp_diff = diff(source[i], target[i], path + "/" + std::to_string(i));
result.insert(result.end(), temp_diff.begin(), temp_diff.end());
++i;
}
// i now reached the end of at least one array
// in a second pass, traverse the remaining elements
// remove my remaining elements
while (i < source.size())
{
result.push_back(object(
{
{"op", "remove"},
{"path", path + "/" + std::to_string(i)}
}));
++i;
}
// add other remaining elements
while (i < target.size())
{
result.push_back(
{
{"op", "add"},
{"path", path + "/" + std::to_string(i)},
{"value", target[i]}
});
++i;
}
break;
}
case value_t::object:
{
// first pass: traverse this object's elements
for (auto it = source.begin(); it != source.end(); ++it)
{
// escape the key name to be used in a JSON patch
const auto key = json_pointer::escape(it.key());
if (target.find(it.key()) != target.end())
{
// recursive call to compare object values at key it
auto temp_diff = diff(it.value(), target[it.key()], path + "/" + key);
result.insert(result.end(), temp_diff.begin(), temp_diff.end());
}
else
{
// found a key that is not in o -> remove it
result.push_back(object(
{
{"op", "remove"},
{"path", path + "/" + key}
}));
}
}
// second pass: traverse other object's elements
for (auto it = target.begin(); it != target.end(); ++it)
{
if (source.find(it.key()) == source.end())
{
// found a key that is not in this -> add it
const auto key = json_pointer::escape(it.key());
result.push_back(
{
{"op", "add"},
{"path", path + "/" + key},
{"value", it.value()}
});
}
}
break;
}
default:
{
// both primitive type: replace value
result.push_back(
{
{"op", "replace"},
{"path", path},
{"value", target}
});
break;
}
}
}
return result;
}
/// @}
};
@ -8821,9 +9365,9 @@ using json = basic_json<>;
}
/////////////////////////
// nonmember functions //
/////////////////////////
///////////////////////
// nonmember support //
///////////////////////
// specialization of std::swap, and std::hash
namespace std

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