Json_path_cache Class Reference

Path cache for JSON functions. More...

#include <item_json_func.h>

Classes
struct	Path_cell
	Struct that points to a cell in m_paths and tells its status. More...

Public Member Functions
	Json_path_cache (THD *thd, uint size)
	Json_path_cache. More...
	~Json_path_cache ()
bool	parse_and_cache_path (const THD *thd, Item **args, uint arg_idx, bool forbid_wildcards)
	Parse a path expression if necessary. More...
const Json_path *	get_path (uint arg_idx) const
	Return an already parsed path expression. More...
void	reset_cache ()
	Reset the cache for re-use when a statement is re-executed. More...

Private Types
enum class	enum_path_status : uint8 { UNINITIALIZED , OK_NOT_NULL , OK_NULL }
	Enum that tells the status of a cell in m_paths. More...

Private Attributes
String	m_path_value
	Holder for path strings. More...
Prealloced_array< Json_path, 8 >	m_paths
	List of paths. More...
Mem_root_array< Path_cell >	m_arg_idx_to_vector_idx
	Map argument indexes to indexes into m_paths. More...

Detailed Description

Path cache for JSON functions.

Caches parsed path objects for arguments which are string literals. Maintains a vector of path objects and an array of ints which map path argument numbers to slots in the array.

Member Enumeration Documentation

enum_path_status

enum class Json_path_cache::enum_path_status : uint8

strongprivate

Enum that tells the status of a cell in m_paths.

Enumerator
UNINITIALIZED
OK_NOT_NULL
OK_NULL

Constructor & Destructor Documentation

Json_path_cache()

Json_path_cache::Json_path_cache	(	THD *	thd,
		uint	size
	)

Json_path_cache.

~Json_path_cache()

Json_path_cache::~Json_path_cache ( )

default

Member Function Documentation

get_path()

const Json_path * Json_path_cache::get_path

(

uint

arg_idx

)

const

Return an already parsed path expression.

Parameters

[in]

arg_idx

Index of the path_expression in the JSON function args

Returns

the already parsed path, possibly NULL

parse_and_cache_path()

bool Json_path_cache::parse_and_cache_path	(	const THD *	thd,
		Item **	args,
		uint	arg_idx,
		bool	forbid_wildcards
	)

Parse a path expression if necessary.

Does nothing if the path expression is constant and it has already been parsed. Assumes that we've already verified that the path expression is not null. Raises an error if the path expression is syntactically incorrect. Raises an error if the path expression contains wildcard tokens but is not supposed to. Otherwise puts the parsed path onto the path vector.

Parameters

[in]	thd	THD handle
[in]	args	Array of args to a JSON function
[in]	arg_idx	Index of the path_expression in args
[in]	forbid_wildcards	True if the path shouldn't contain * or **

Returns

false on success (valid path or NULL), true on error

reset_cache()

void Json_path_cache::reset_cache

(

)

Reset the cache for re-use when a statement is re-executed.

Member Data Documentation

m_arg_idx_to_vector_idx

Mem_root_array<Path_cell> Json_path_cache::m_arg_idx_to_vector_idx

private

Map argument indexes to indexes into m_paths.

m_path_value

String Json_path_cache::m_path_value

private

Holder for path strings.

m_paths

Prealloced_array<Json_path, 8> Json_path_cache::m_paths

private

List of paths.

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

• sql/item_json_func.h
• sql/item_json_func.cc