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🔨 using the SAX-DOM parser

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This commit is contained in:
Niels Lohmann 2018-03-06 18:17:07 +01:00
parent faf2546a15
commit 5beab80553
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GPG key ID: 7F3CEA63AE251B69
6 changed files with 173 additions and 166 deletions
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43
include/nlohmann/detail/input/json_sax.hpp
View file

@ -132,6 +132,10 @@ class json_sax_dom_parser : public json_sax<BasicJsonType>
using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
using number_float_t = typename BasicJsonType::number_float_t;
json_sax_dom_parser(BasicJsonType& r, const bool allow_exceptions_ = true)
: root(r), allow_exceptions(allow_exceptions_)
{}
bool null() override
{
handle_value(nullptr);
@ -204,25 +208,30 @@ class json_sax_dom_parser : public json_sax<BasicJsonType>
return true;
}
bool parse_error(std::size_t position, const std::string&, const std::string& error_msg) override
bool parse_error(std::size_t position, const std::string& token,
const std::string& error_msg) override
{
JSON_THROW(BasicJsonType::parse_error::create(101, position, error_msg));
errored = true;
if (allow_exceptions)
{
if (error_msg == "number overflow")
{
JSON_THROW(BasicJsonType::out_of_range::create(406, "number overflow parsing '" + token + "'"));
}
else
{
JSON_THROW(BasicJsonType::parse_error::create(101, position, error_msg));
}
}
return false;
}
BasicJsonType& get_value()
bool is_errored() const
{
return root;
return errored;
}
private:
/// the parsed JSON value
BasicJsonType root;
/// stack to model hierarchy of values
std::vector<BasicJsonType*> ref_stack;
/// helper to hold the reference for the next object element
BasicJsonType* object_element = nullptr;
/*!
@invariant If the ref stack is empty, then the passed value will be the new
root.
@ -234,7 +243,6 @@ class json_sax_dom_parser : public json_sax<BasicJsonType>
{
if (ref_stack.empty())
{
assert(root.is_null());
root = BasicJsonType(std::forward<Value>(v));
return &root;
}
@ -254,6 +262,17 @@ class json_sax_dom_parser : public json_sax<BasicJsonType>
}
}
}
/// the parsed JSON value
BasicJsonType& root;
/// stack to model hierarchy of values
std::vector<BasicJsonType*> ref_stack;
/// helper to hold the reference for the next object element
BasicJsonType* object_element = nullptr;
/// whether a syntax error occurred
bool errored = false;
/// whether to throw exceptions in case of errors
const bool allow_exceptions = true;
};
}

90
include/nlohmann/detail/input/parser.hpp
View file

@ -63,11 +63,10 @@ class parser
const parser_callback_t cb = nullptr,
const bool allow_exceptions_ = true)
: callback(cb), m_lexer(adapter), allow_exceptions(allow_exceptions_)
{}
parser(detail::input_adapter_t adapter, json_sax_t* s)
: m_lexer(adapter), sax(s)
{}
{
// read first token
get_token();
}
/*!
@brief public parser interface
@ -81,31 +80,52 @@ class parser
*/
void parse(const bool strict, BasicJsonType& result)
{
// read first token
get_token();
parse_internal(true, result);
result.assert_invariant();
// in strict mode, input must be completely read
if (strict)
if (callback)
{
get_token();
expect(token_type::end_of_input);
parse_internal(true, result);
result.assert_invariant();
// in strict mode, input must be completely read
if (strict)
{
get_token();
expect(token_type::end_of_input);
}
// in case of an error, return discarded value
if (errored)
{
result = value_t::discarded;
return;
}
// set top-level value to null if it was discarded by the callback
// function
if (result.is_discarded())
{
result = nullptr;
}
}
// in case of an error, return discarded value
if (errored)
else
{
result = value_t::discarded;
return;
}
json_sax_dom_parser<BasicJsonType> sdp(result, allow_exceptions);
sax_parse_internal(&sdp);
result.assert_invariant();
// set top-level value to null if it was discarded by the callback
// function
if (result.is_discarded())
{
result = nullptr;
// in strict mode, input must be completely read
if (strict and (get_token() != token_type::end_of_input))
{
sdp.parse_error(m_lexer.get_position(),
m_lexer.get_token_string(),
exception_message(token_type::end_of_input));
}
// in case of an error, return discarded value
if (sdp.is_errored())
{
result = value_t::discarded;
return;
}
}
}
@ -117,9 +137,6 @@ class parser
*/
bool accept(const bool strict = true)
{
// read first token
get_token();
if (not accept_internal())
{
return false;
@ -129,12 +146,9 @@ class parser
return not strict or (get_token() == token_type::end_of_input);
}
bool sax_parse()
bool sax_parse(json_sax_t* sax)
{
// read first token
get_token();
return sax_parse_internal();
return sax_parse_internal(sax);
}
private:
@ -535,7 +549,7 @@ class parser
}
}
bool sax_parse_internal()
bool sax_parse_internal(json_sax_t* sax)
{
switch (last_token)
{
@ -584,7 +598,7 @@ class parser
// parse value
get_token();
if (not sax_parse_internal())
if (not sax_parse_internal(sax))
{
return false;
}
@ -631,7 +645,7 @@ class parser
while (true)
{
// parse value
if (not sax_parse_internal())
if (not sax_parse_internal(sax))
{
return false;
}
@ -782,8 +796,6 @@ class parser
bool errored = false;
/// whether to throw exceptions in case of errors
const bool allow_exceptions = true;
/// associated SAX parse event receiver
json_sax_t* sax = nullptr;
};
}
}

6
include/nlohmann/json.hpp
View file

@ -5930,12 +5930,12 @@ class basic_json
static bool sax_parse(detail::input_adapter i, json_sax_t* sax)
{
return parser(i, sax).sax_parse();
return parser(i).sax_parse(sax);
}
static bool sax_parse(detail::input_adapter& i, json_sax_t* sax)
{
return parser(i, sax).sax_parse();
return parser(i).sax_parse(sax);
}
/*!
@ -6013,7 +6013,7 @@ class basic_json
typename std::iterator_traits<IteratorType>::iterator_category>::value, int>::type = 0>
static bool sax_parse(IteratorType first, IteratorType last, json_sax_t* sax)
{
return parser(detail::input_adapter(first, last), sax).sax_parse();
return parser(detail::input_adapter(first, last)).sax_parse(sax);
}
/*!