text: /*-------------------------------------------------------------------------
   *
   * jsonapi.h
   *	  Declarations for JSON API support.
   *
   * Portions Copyright (c) 1996-2017, 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 "jsonb.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;
  
  
  /*
   * All the fields in this structure should be treated as read-only.
   *
   * If strval is not null, then it should contain the de-escaped value
   * of the lexeme if it's a string. Otherwise most of these field names
   * should be self-explanatory.
   *
   * line_number and line_start are principally for use by the parser's
   * error reporting routines.
   * token_terminator and prev_token_terminator point to the character
   * AFTER the end of the token, i.e. where there would be a nul byte
   * if we were using nul-terminated strings.
   */
  typedef struct JsonLexContext
  {
  	char	   *input;
  	int			input_length;
  	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);
  
  
  /*
   * Semantic Action structure for use in parsing json.
   * Any of these actions can be NULL, in which case nothing is done at that
   * point, Likewise, semstate can be NULL. Using an all-NULL structure amounts
   * to doing a pure parse with no side-effects, and is therefore exactly
   * what the json input routines do.
   *
   * The 'fname' and 'token' strings passed to these actions are palloc'd.
   * They are not free'd or used further by the parser, so the action function
   * is free to do what it wishes with them.
   */
  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;
  
  /*
   * 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);
  
  /*
   * json_count_array_elements performs a fast secondary parse to determine the
   * number of elements in passed array lex context. It should be called from an
   * array_start action.
   */
  extern int	json_count_array_elements(JsonLexContext *lex);
  
  /*
   * constructors for JsonLexContext, with or without strval element.
   * If supplied, the strval element will contain a de-escaped version of
   * the lexeme. However, doing this imposes a performance penalty, so
   * it should be avoided if the de-escaped lexeme is not required.
   *
   * If you already have the json as a text* value, use the first of these
   * functions, otherwise use  makeJsonLexContextCstringLen().
   */
  extern JsonLexContext *makeJsonLexContext(text *json, bool need_escapes);
  extern JsonLexContext *makeJsonLexContextCstringLen(char *json,
  							 int len,
  							 bool need_escapes);
  
  /*
   * Utility function to check if a string is a valid JSON number.
   *
   * str argument does not need to be nul-terminated.
   */
  extern bool IsValidJsonNumber(const char *str, int len);
  
  /* an action that will be applied to each value in iterate_json(b)_string_vaues functions */
  typedef void (*JsonIterateStringValuesAction) (void *state, char *elem_value, int elem_len);
  
  /* an action that will be applied to each value in transform_json(b)_string_values functions */
  typedef text *(*JsonTransformStringValuesAction) (void *state, char *elem_value, int elem_len);
  
  extern void iterate_jsonb_string_values(Jsonb *jb, void *state,
  							JsonIterateStringValuesAction action);
  extern void iterate_json_string_values(text *json, void *action_state,
  						   JsonIterateStringValuesAction action);
  extern Jsonb *transform_jsonb_string_values(Jsonb *jsonb, void *action_state,
  						   JsonTransformStringValuesAction transform_action);
  extern text *transform_json_string_values(text *json, void *action_state,
  						   JsonTransformStringValuesAction transform_action);
  
  #endif   /* JSONAPI_H */
  