json_path.h File Reference

This file contains interface support for the JSON path abstraction. More...

#include <assert.h>
#include <stddef.h>
#include <algorithm>
#include <functional>
#include <new>
#include <string>
#include <utility>
#include "my_alloc.h"
#include "my_inttypes.h"
#include "my_sys.h"
#include "prealloced_array.h"
#include "sql-common/json_error_handler.h"

Go to the source code of this file.

Classes
class	Json_array_index
	A class that represents the index of an element in a JSON array. More...
class	Json_path_leg
	One path leg in a JSON path expression. More...
struct	Json_path_leg::Array_range
	A structure that represents an array range. More...
class	Json_seekable_path
	A path expression which can be used to seek to a position inside a JSON value. More...
class	Json_path
	A JSON path expression. More...
class	Json_path_clone
	A lightweight path expression. More...

Typedefs
using	Json_path_leg_pointers = Prealloced_array< const Json_path_leg *, 8 >
using	Json_path_iterator = Json_path_leg_pointers::const_iterator

Enumerations
enum	enum_json_path_leg_type {   jpl_member , jpl_array_cell , jpl_array_range , jpl_member_wildcard ,   jpl_array_cell_wildcard , jpl_ellipsis }
	The type of a Json_path_leg. More...

Functions
bool	parse_path (size_t path_length, const char *path_expression, Json_path *path, size_t *bad_index, const JsonDocumentDepthHandler &depth_handler)
	Initialize a Json_path from a path expression. More...
bool	parse_path (const String &path_value, bool forbid_wildcards, Json_path *json_path)
	A helper function that uses the above one as workhorse. More...

Detailed Description

This file contains interface support for the JSON path abstraction.

The path abstraction is described by the functional spec attached to WL#7909.

Typedef Documentation

Json_path_iterator

using Json_path_iterator = Json_path_leg_pointers::const_iterator

Json_path_leg_pointers

using Json_path_leg_pointers = Prealloced_array<const Json_path_leg *, 8>

Enumeration Type Documentation

enum_json_path_leg_type

enum enum_json_path_leg_type

The type of a Json_path_leg.

Enumerator
jpl_member	A path leg that represents a JSON object member (such as .name). This path leg matches a single member in a JSON object.
jpl_array_cell	A path leg that represents a JSON array cell (such as [10]). This path leg matches a single element in a JSON object.
jpl_array_range	A path leg that represents a range in a JSON array (such as [2 to 7]).
jpl_member_wildcard	A path leg that represents the member wildcard. A path leg that represents the member wildcard (.*), which matches all the members of a JSON object.
jpl_array_cell_wildcard	A path leg that represents the array wildcard ([*]), which matches all the elements of a JSON array.
jpl_ellipsis	A path leg that represents the ellipsis (**), which matches any JSON value and recursively all the JSON values nested within it if it is an object or an array.

Function Documentation

parse_path() [1/2]

bool parse_path	(	const String &	path_value,
		bool	forbid_wildcards,
		Json_path *	json_path
	)

A helper function that uses the above one as workhorse.

Entry point for for JSON_TABLE (Table_function_json class) and Json_path_cache. 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 updates the supplied Json_path object with the parsed path.

Parameters

[in]	path_value	A String to be interpreted as a path.
[in]	forbid_wildcards	True if the path shouldn't contain * or **
[out]	json_path	The object that will hold the parsed path

Returns

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

parse_path() [2/2]

bool parse_path	(	size_t	path_length,
		const char *	path_expression,
		Json_path *	path,
		size_t *	bad_index,
		const JsonDocumentDepthHandler &	depth_handler
	)

Initialize a Json_path from a path expression.

Stops parsing on the first error. It initializes the Json_path and returns false if the path is parsed successfully. Otherwise, it returns false. In that case, the output bad_index argument will contain an index into the path expression. The parsing failed near that index.

Parameters

[in]	path_length	The length of the path expression.
[in]	path_expression	The string form of the path expression.
[out]	path	The Json_path object to be initialized.
[out]	bad_index	If null is returned, the parsing failed around here.
[in]	depth_handler	Pointer to a function that should handle error occurred when depth is exceeded.

Returns

false on success, true on error

Initialize a Json_path from a path expression.