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224 lines
7.2 KiB
224 lines
7.2 KiB
/*-------------------------------------------------------------------------
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*
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* jsonapi.h
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* Declarations for JSON API support.
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*
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* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/common/jsonapi.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef JSONAPI_H
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#define JSONAPI_H
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#include "lib/stringinfo.h"
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typedef enum JsonTokenType
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{
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JSON_TOKEN_INVALID,
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JSON_TOKEN_STRING,
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JSON_TOKEN_NUMBER,
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JSON_TOKEN_OBJECT_START,
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JSON_TOKEN_OBJECT_END,
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JSON_TOKEN_ARRAY_START,
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JSON_TOKEN_ARRAY_END,
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JSON_TOKEN_COMMA,
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JSON_TOKEN_COLON,
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JSON_TOKEN_TRUE,
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JSON_TOKEN_FALSE,
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JSON_TOKEN_NULL,
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JSON_TOKEN_END,
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} JsonTokenType;
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typedef enum JsonParseErrorType
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{
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JSON_SUCCESS,
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JSON_INCOMPLETE,
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JSON_INVALID_LEXER_TYPE,
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JSON_NESTING_TOO_DEEP,
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JSON_ESCAPING_INVALID,
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JSON_ESCAPING_REQUIRED,
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JSON_EXPECTED_ARRAY_FIRST,
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JSON_EXPECTED_ARRAY_NEXT,
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JSON_EXPECTED_COLON,
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JSON_EXPECTED_END,
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JSON_EXPECTED_JSON,
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JSON_EXPECTED_MORE,
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JSON_EXPECTED_OBJECT_FIRST,
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JSON_EXPECTED_OBJECT_NEXT,
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JSON_EXPECTED_STRING,
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JSON_INVALID_TOKEN,
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JSON_UNICODE_CODE_POINT_ZERO,
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JSON_UNICODE_ESCAPE_FORMAT,
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JSON_UNICODE_HIGH_ESCAPE,
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JSON_UNICODE_UNTRANSLATABLE,
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JSON_UNICODE_HIGH_SURROGATE,
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JSON_UNICODE_LOW_SURROGATE,
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JSON_SEM_ACTION_FAILED, /* error should already be reported */
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} JsonParseErrorType;
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/* Parser state private to jsonapi.c */
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typedef struct JsonParserStack JsonParserStack;
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typedef struct JsonIncrementalState JsonIncrementalState;
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/*
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* All the fields in this structure should be treated as read-only.
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*
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* If strval is not null, then it should contain the de-escaped value
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* of the lexeme if it's a string. Otherwise most of these field names
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* should be self-explanatory.
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*
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* line_number and line_start are principally for use by the parser's
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* error reporting routines.
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* token_terminator and prev_token_terminator point to the character
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* AFTER the end of the token, i.e. where there would be a nul byte
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* if we were using nul-terminated strings.
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*
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* The prev_token_terminator field should not be used when incremental is
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* true, as the previous token might have started in a previous piece of input,
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* and thus it can't be used in any pointer arithmetic or other operations in
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* conjunction with token_start.
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*
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* JSONLEX_FREE_STRUCT/STRVAL are used to drive freeJsonLexContext.
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*/
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#define JSONLEX_FREE_STRUCT (1 << 0)
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#define JSONLEX_FREE_STRVAL (1 << 1)
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typedef struct JsonLexContext
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{
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char *input;
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int input_length;
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int input_encoding;
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char *token_start;
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char *token_terminator;
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char *prev_token_terminator;
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bool incremental;
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JsonTokenType token_type;
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int lex_level;
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bits32 flags;
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int line_number; /* line number, starting from 1 */
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char *line_start; /* where that line starts within input */
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JsonParserStack *pstack;
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JsonIncrementalState *inc_state;
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StringInfo strval;
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StringInfo errormsg;
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} JsonLexContext;
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typedef JsonParseErrorType (*json_struct_action) (void *state);
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typedef JsonParseErrorType (*json_ofield_action) (void *state, char *fname, bool isnull);
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typedef JsonParseErrorType (*json_aelem_action) (void *state, bool isnull);
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typedef JsonParseErrorType (*json_scalar_action) (void *state, char *token, JsonTokenType tokentype);
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/*
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* Semantic Action structure for use in parsing json.
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*
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* Any of these actions can be NULL, in which case nothing is done at that
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* point, Likewise, semstate can be NULL. Using an all-NULL structure amounts
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* to doing a pure parse with no side-effects, and is therefore exactly
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* what the json input routines do.
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*
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* The 'fname' and 'token' strings passed to these actions are palloc'd.
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* They are not free'd or used further by the parser, so the action function
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* is free to do what it wishes with them.
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*
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* All action functions return JsonParseErrorType. If the result isn't
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* JSON_SUCCESS, the parse is abandoned and that error code is returned.
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* If it is JSON_SEM_ACTION_FAILED, the action function is responsible
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* for having reported the error in some appropriate way.
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*/
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typedef struct JsonSemAction
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{
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void *semstate;
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json_struct_action object_start;
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json_struct_action object_end;
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json_struct_action array_start;
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json_struct_action array_end;
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json_ofield_action object_field_start;
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json_ofield_action object_field_end;
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json_aelem_action array_element_start;
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json_aelem_action array_element_end;
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json_scalar_action scalar;
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} JsonSemAction;
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/*
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* pg_parse_json will parse the string in the lex calling the
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* action functions in sem at the appropriate points. It is
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* up to them to keep what state they need in semstate. If they
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* need access to the state of the lexer, then its pointer
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* should be passed to them as a member of whatever semstate
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* points to. If the action pointers are NULL the parser
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* does nothing and just continues.
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*/
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extern JsonParseErrorType pg_parse_json(JsonLexContext *lex,
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JsonSemAction *sem);
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extern JsonParseErrorType pg_parse_json_incremental(JsonLexContext *lex,
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JsonSemAction *sem,
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char *json,
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int len,
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bool is_last);
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/* the null action object used for pure validation */
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extern PGDLLIMPORT JsonSemAction nullSemAction;
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/*
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* json_count_array_elements performs a fast secondary parse to determine the
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* number of elements in passed array lex context. It should be called from an
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* array_start action.
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*
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* The return value indicates whether any error occurred, while the number
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* of elements is stored into *elements (but only if the return value is
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* JSON_SUCCESS).
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*/
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extern JsonParseErrorType json_count_array_elements(JsonLexContext *lex,
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int *elements);
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/*
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* initializer for JsonLexContext.
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*
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* If a valid 'lex' pointer is given, it is initialized. This can be used
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* for stack-allocated structs, saving overhead. If NULL is given, a new
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* struct is allocated.
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*
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* If need_escapes is true, ->strval stores the unescaped lexemes.
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* Unescaping is expensive, so only request it when necessary.
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*
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* If need_escapes is true or lex was given as NULL, then the caller is
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* responsible for freeing the returned struct, either by calling
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* freeJsonLexContext() or (in backend environment) via memory context
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* cleanup.
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*/
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extern JsonLexContext *makeJsonLexContextCstringLen(JsonLexContext *lex,
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char *json,
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int len,
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int encoding,
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bool need_escapes);
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/*
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* make a JsonLexContext suitable for incremental parsing.
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* the string chunks will be handed to pg_parse_json_incremental,
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* so there's no need for them here.
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*/
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extern JsonLexContext *makeJsonLexContextIncremental(JsonLexContext *lex,
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int encoding,
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bool need_escapes);
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extern void freeJsonLexContext(JsonLexContext *lex);
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/* lex one token */
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extern JsonParseErrorType json_lex(JsonLexContext *lex);
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/* construct an error detail string for a json error */
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extern char *json_errdetail(JsonParseErrorType error, JsonLexContext *lex);
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/*
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* Utility function to check if a string is a valid JSON number.
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*
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* str argument does not need to be nul-terminated.
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*/
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extern bool IsValidJsonNumber(const char *str, int len);
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#endif /* JSONAPI_H */
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