Json_dom Class Reference

JSON DOM abstract base class. More...

#include <json_dom.h>

Inheritance diagram for Json_dom:

Public Member Functions
virtual	~Json_dom ()=default
void *	operator new (size_t size, const std::nothrow_t &) noexcept
	Allocate space on the heap for a Json_dom object. More...
void	operator delete (void *ptr) noexcept
	Deallocate the space used by a Json_dom object. More...
void	operator delete (void *ptr, const std::nothrow_t &) noexcept
	Nothrow delete. More...
Json_container *	parent () const
	Get the parent dom to which this dom is attached. More...
virtual enum_json_type	json_type () const =0
virtual bool	is_scalar () const
virtual bool	is_number () const
virtual uint32	depth () const =0
	Compute the depth of a document. More...
virtual Json_dom_ptr	clone () const =0
	Make a deep clone. More...
Json_path	get_location () const
	Get the path location of this dom, measured from the outermost document it nests inside. More...
bool	seek (const Json_seekable_path &path, size_t legs, Json_dom_vector *hits, bool auto_wrap, bool only_need_one)
	Finds all of the json sub-documents which match the path expression. More...

Static Public Member Functions
static Json_dom_ptr	parse (const char *text, size_t length, const JsonParseErrorHandler &error_handler, const JsonErrorHandler &depth_handler)
	Parse Json text to DOM (using rapidjson). More...
static Json_dom_ptr	parse (const json_binary::Value &v)
	Construct a DOM object based on a binary JSON value. More...

Private Member Functions
void	set_parent (Json_container *parent)
	Set the parent dom to which this dom is attached. More...

Private Attributes
Json_container *	m_parent {nullptr}
	Parent pointer. More...

Friends
class	Json_object
class	Json_array

Detailed Description

JSON DOM abstract base class.

MySQL representation of in-memory JSON objects used by the JSON type Supports access, deep cloning, and updates. See also Json_wrapper and json_binary::Value. Uses heap for space allocation for now. FIXME.

Class hierarchy:

    Json_dom (abstract)
     Json_scalar (abstract)
       Json_string
       Json_number (abstract)
         Json_decimal
         Json_int
         Json_uint
         Json_double
       Json_boolean
       Json_null
       Json_datetime
       Json_opaque
     Json_container (abstract)
       Json_object
       Json_array

At the outset, object and array add/insert/append operations takes a clone unless specified in the method, e.g. add_alias hands the responsibility for the passed in object over to the object.

Constructor & Destructor Documentation

~Json_dom()

virtual Json_dom::~Json_dom ( )

virtualdefault

Member Function Documentation

clone()

virtual Json_dom_ptr Json_dom::clone ( ) const

pure virtual

Make a deep clone.

The ownership of the returned object is henceforth with the caller.

Returns

a cloned Json_dom object.

Implemented in Json_object, Json_array, Json_string, Json_decimal, Json_double, Json_int, Json_uint, Json_null, Json_datetime, Json_opaque, and Json_boolean.

depth()

virtual uint32 Json_dom::depth ( ) const

pure virtual

Compute the depth of a document.

This is the value which would be returned by the JSON_DEPTH() system function.

• for scalar values, empty array and empty object: 1
• for non-empty array: 1+ max(depth of array elements)
• for non-empty objects: 1+ max(depth of object values)

For example: "abc", [] and {} have depth 1. ["abc", [3]] and {"a": "abc", "b": [3]} have depth 3.

Returns

the depth of the document

Implemented in Json_scalar, Json_object, and Json_array.

get_location()

Json_path Json_dom::get_location

(

)

const

Get the path location of this dom, measured from the outermost document it nests inside.

is_number()

virtual bool Json_dom::is_number ( ) const

inlinevirtual

Returns

true of the object is a subclass of Json_number

Reimplemented in Json_number.

is_scalar()

virtual bool Json_dom::is_scalar ( ) const

inlinevirtual

Returns

true if the object is a subclass of Json_scalar

Reimplemented in Json_scalar.

json_type()

virtual enum_json_type Json_dom::json_type ( ) const

pure virtual

Returns

the type corresponding to the actual Json_dom subclass

Implemented in Json_object, Json_array, Json_string, Json_decimal, Json_double, Json_int, Json_uint, Json_null, Json_datetime, Json_opaque, and Json_boolean.

operator delete() [1/2]

void Json_dom::operator delete ( void *  ptr )

noexcept

Deallocate the space used by a Json_dom object.

operator delete() [2/2]

void Json_dom::operator delete ( void *  ptr, const std::nothrow_t &    )

noexcept

Nothrow delete.

operator new()

void * Json_dom::operator new ( size_t  size, const std::nothrow_t &    )

noexcept

Allocate space on the heap for a Json_dom object.

Returns

pointer to the allocated memory, or NULL if memory could not be allocated (in which case my_error() will have been called with the appropriate error message)

parent()

Json_container * Json_dom::parent ( ) const

inline

Get the parent dom to which this dom is attached.

Returns

the parent dom.

parse() [1/2]

Json_dom_ptr Json_dom::parse ( const char *  text, size_t  length, const JsonParseErrorHandler &  error_handler, const JsonErrorHandler &  depth_handler  )

static

Parse Json text to DOM (using rapidjson).

The text must be valid JSON. The results when supplying an invalid document is undefined. The ownership of the returned object is henceforth with the caller.

If the parsing fails because of a syntax error, the errmsg and offset arguments will be given values that point to a detailed error message and where the syntax error was located. The caller will have to generate an error message with my_error() in this case.

If the parsing fails because of some other error (such as out of memory), errmsg will point to a location that holds the value NULL. In this case, parse() will already have called my_error(), and the caller doesn't need to generate an error message.

Parameters

[in]	text	the JSON text
[in]	length	the length of the text
[in]	error_handler	Pointer to a function that should handle reporting of parsing error.
[in]	depth_handler	Pointer to a function that should handle error occurred when depth is exceeded.

Returns

the built DOM if JSON text was parseable, else NULL

parse() [2/2]

Json_dom_ptr Json_dom::parse ( const json_binary::Value &  v )

static

Construct a DOM object based on a binary JSON value.

The ownership of the returned object is henceforth with the caller.

Parameters

v	the binary value to parse

Returns

a DOM representation of the binary value, or NULL on error

seek()

bool Json_dom::seek	(	const Json_seekable_path &	path,
		size_t	legs,
		Json_dom_vector *	hits,
		bool	auto_wrap,
		bool	only_need_one
	)

Finds all of the json sub-documents which match the path expression.

Adds a vector element for each match.

See the header comment for Json_wrapper.seek() for a discussion of complexities involving path expression with more than one ellipsis (**) token.

Parameters

[in]	path	the (possibly wildcarded) address of the sub-documents
[in]	legs	the number of legs to use from path
[out]	hits	one element per match
[in]	auto_wrap	if true, match a tailing [0] to scalar at that position.
[in]	only_need_one	True if we can stop after finding one match

Returns

false on success, true on error

set_parent()

void Json_dom::set_parent ( Json_container *  parent )

inlineprivate

Set the parent dom to which this dom is attached.

Parameters

[in]

parent

the parent we're being attached to

Friends And Related Function Documentation

Json_array

friend class Json_array

friend

Json_object

friend class Json_object

friend

Member Data Documentation

m_parent

Json_container* Json_dom::m_parent {nullptr}

private

Parent pointer.

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The documentation for this class was generated from the following files:

• sql-common/json_dom.h
• sql-common/json_dom.cc