Source

pgdevel / src / include / utils / jsonapi.h

/*-------------------------------------------------------------------------
 *
 * jsonapi.h
 *	  Declarations for JSON API support.
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/utils/jsonapi.h
 *
 *-------------------------------------------------------------------------
 */

#ifndef JSONAPI_H
#define JSONAPI_H

#include "lib/stringinfo.h"

typedef enum
{
	JSON_TOKEN_INVALID,
	JSON_TOKEN_STRING,
	JSON_TOKEN_NUMBER,
	JSON_TOKEN_OBJECT_START,
	JSON_TOKEN_OBJECT_END,
	JSON_TOKEN_ARRAY_START,
	JSON_TOKEN_ARRAY_END,
	JSON_TOKEN_COMMA,
	JSON_TOKEN_COLON,
	JSON_TOKEN_TRUE,
	JSON_TOKEN_FALSE,
	JSON_TOKEN_NULL,
	JSON_TOKEN_END,
}	JsonTokenType;

typedef struct JsonLexContext
{
	char	   *input;
	char	   *token_start;
	char	   *token_terminator;
	char	   *prev_token_terminator;
	JsonTokenType token_type;
	int         lex_level;
	int			line_number;
	char	   *line_start;
	StringInfo	strval;
}	JsonLexContext;

typedef void (*json_struct_action) (void *state);
typedef void (*json_ofield_action) (void *state, char *fname, bool isnull);
typedef void (*json_aelem_action) (void *state, bool isnull);
typedef void (*json_scalar_action) (void *state, char *token, JsonTokenType tokentype);


/*
 * any of these actions can be NULL, in which case nothig is done.
 */
typedef struct jsonSemAction
{
	void	   *semstate;
	json_struct_action object_start;
	json_struct_action object_end;
	json_struct_action array_start;
	json_struct_action array_end;
	json_ofield_action object_field_start;
	json_ofield_action object_field_end;
	json_aelem_action array_element_start;
	json_aelem_action array_element_end;
	json_scalar_action scalar;
}	jsonSemAction, *JsonSemAction;

/*
 * parse_json will parse the string in the lex calling the
 * action functions in sem at the appropriate points. It is
 * up to them to keep what state they need	in semstate. If they
 * need access to the state of the lexer, then its pointer
 * should be passed to them as a member of whatever semstate
 * points to. If the action pointers are NULL the parser
 * does nothing and just continues.
 */
extern void pg_parse_json(JsonLexContext * lex, JsonSemAction sem);

/* constructor for JsonLexContext, with or without strval element */
extern JsonLexContext *makeJsonLexContext(char * json, bool need_escapes);

#endif   /* JSONAPI_H */