/*------------------------------------------------------------------------- * * jsonapi.c * JSON parser and lexer interfaces * * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION * src/backend/utils/adt/jsonapi.c * *------------------------------------------------------------------------- */ #include "postgres.h" #include "mb/pg_wchar.h" #include "miscadmin.h" #include "utils/jsonapi.h" /* * The context of the parser is maintained by the recursive descent * mechanism, but is passed explicitly to the error reporting routine * for better diagnostics. */ typedef enum /* contexts of JSON parser */ { JSON_PARSE_VALUE, /* expecting a value */ JSON_PARSE_STRING, /* expecting a string (for a field name) */ JSON_PARSE_ARRAY_START, /* saw '[', expecting value or ']' */ JSON_PARSE_ARRAY_NEXT, /* saw array element, expecting ',' or ']' */ JSON_PARSE_OBJECT_START, /* saw '{', expecting label or '}' */ JSON_PARSE_OBJECT_LABEL, /* saw object label, expecting ':' */ JSON_PARSE_OBJECT_NEXT, /* saw object value, expecting ',' or '}' */ JSON_PARSE_OBJECT_COMMA, /* saw object ',', expecting next label */ JSON_PARSE_END /* saw the end of a document, expect nothing */ } JsonParseContext; static inline void json_lex_string(JsonLexContext *lex); static inline void json_lex_number(JsonLexContext *lex, char *s, bool *num_err, int *total_len); static inline void parse_scalar(JsonLexContext *lex, JsonSemAction *sem); static void parse_object_field(JsonLexContext *lex, JsonSemAction *sem); static void parse_object(JsonLexContext *lex, JsonSemAction *sem); static void parse_array_element(JsonLexContext *lex, JsonSemAction *sem); static void parse_array(JsonLexContext *lex, JsonSemAction *sem); static void report_parse_error(JsonParseContext ctx, JsonLexContext *lex) pg_attribute_noreturn(); static void report_invalid_token(JsonLexContext *lex) pg_attribute_noreturn(); static int report_json_context(JsonLexContext *lex); static char *extract_mb_char(char *s); /* the null action object used for pure validation */ JsonSemAction nullSemAction = { NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL }; /* Recursive Descent parser support routines */ /* * lex_peek * * what is the current look_ahead token? */ static inline JsonTokenType lex_peek(JsonLexContext *lex) { return lex->token_type; } /* * lex_accept * * accept the look_ahead token and move the lexer to the next token if the * look_ahead token matches the token parameter. In that case, and if required, * also hand back the de-escaped lexeme. * * returns true if the token matched, false otherwise. */ static inline bool lex_accept(JsonLexContext *lex, JsonTokenType token, char **lexeme) { if (lex->token_type == token) { if (lexeme != NULL) { if (lex->token_type == JSON_TOKEN_STRING) { if (lex->strval != NULL) *lexeme = pstrdup(lex->strval->data); } else { int len = (lex->token_terminator - lex->token_start); char *tokstr = palloc(len + 1); memcpy(tokstr, lex->token_start, len); tokstr[len] = '\0'; *lexeme = tokstr; } } json_lex(lex); return true; } return false; } /* * lex_accept * * move the lexer to the next token if the current look_ahead token matches * the parameter token. Otherwise, report an error. */ static inline void lex_expect(JsonParseContext ctx, JsonLexContext *lex, JsonTokenType token) { if (!lex_accept(lex, token, NULL)) report_parse_error(ctx, lex); } /* chars to consider as part of an alphanumeric token */ #define JSON_ALPHANUMERIC_CHAR(c) \ (((c) >= 'a' && (c) <= 'z') || \ ((c) >= 'A' && (c) <= 'Z') || \ ((c) >= '0' && (c) <= '9') || \ (c) == '_' || \ IS_HIGHBIT_SET(c)) /* * Utility function to check if a string is a valid JSON number. * * str is of length len, and need not be null-terminated. */ bool IsValidJsonNumber(const char *str, int len) { bool numeric_error; int total_len; JsonLexContext dummy_lex; if (len <= 0) return false; /* * json_lex_number expects a leading '-' to have been eaten already. * * having to cast away the constness of str is ugly, but there's not much * easy alternative. */ if (*str == '-') { dummy_lex.input = unconstify(char *, str) +1; dummy_lex.input_length = len - 1; } else { dummy_lex.input = unconstify(char *, str); dummy_lex.input_length = len; } json_lex_number(&dummy_lex, dummy_lex.input, &numeric_error, &total_len); return (!numeric_error) && (total_len == dummy_lex.input_length); } /* * makeJsonLexContext * * lex constructor, with or without StringInfo object * for de-escaped lexemes. * * Without is better as it makes the processing faster, so only make one * if really required. * * If you already have the json as a text* value, use the first of these * functions, otherwise use makeJsonLexContextCstringLen(). */ JsonLexContext * makeJsonLexContext(text *json, bool need_escapes) { return makeJsonLexContextCstringLen(VARDATA_ANY(json), VARSIZE_ANY_EXHDR(json), need_escapes); } JsonLexContext * makeJsonLexContextCstringLen(char *json, int len, bool need_escapes) { JsonLexContext *lex = palloc0(sizeof(JsonLexContext)); lex->input = lex->token_terminator = lex->line_start = json; lex->line_number = 1; lex->input_length = len; if (need_escapes) lex->strval = makeStringInfo(); return lex; } /* * pg_parse_json * * Publicly visible entry point for the JSON parser. * * lex is a lexing context, set up for the json to be processed by calling * makeJsonLexContext(). sem is a structure of function pointers to semantic * action routines to be called at appropriate spots during parsing, and a * pointer to a state object to be passed to those routines. */ void pg_parse_json(JsonLexContext *lex, JsonSemAction *sem) { JsonTokenType tok; /* get the initial token */ json_lex(lex); tok = lex_peek(lex); /* parse by recursive descent */ switch (tok) { case JSON_TOKEN_OBJECT_START: parse_object(lex, sem); break; case JSON_TOKEN_ARRAY_START: parse_array(lex, sem); break; default: parse_scalar(lex, sem); /* json can be a bare scalar */ } lex_expect(JSON_PARSE_END, lex, JSON_TOKEN_END); } /* * json_count_array_elements * * Returns number of array elements in lex context at start of array token * until end of array token at same nesting level. * * Designed to be called from array_start routines. */ int json_count_array_elements(JsonLexContext *lex) { JsonLexContext copylex; int count; /* * It's safe to do this with a shallow copy because the lexical routines * don't scribble on the input. They do scribble on the other pointers * etc, so doing this with a copy makes that safe. */ memcpy(©lex, lex, sizeof(JsonLexContext)); copylex.strval = NULL; /* not interested in values here */ copylex.lex_level++; count = 0; lex_expect(JSON_PARSE_ARRAY_START, ©lex, JSON_TOKEN_ARRAY_START); if (lex_peek(©lex) != JSON_TOKEN_ARRAY_END) { do { count++; parse_array_element(©lex, &nullSemAction); } while (lex_accept(©lex, JSON_TOKEN_COMMA, NULL)); } lex_expect(JSON_PARSE_ARRAY_NEXT, ©lex, JSON_TOKEN_ARRAY_END); return count; } /* * Recursive Descent parse routines. There is one for each structural * element in a json document: * - scalar (string, number, true, false, null) * - array ( [ ] ) * - array element * - object ( { } ) * - object field */ static inline void parse_scalar(JsonLexContext *lex, JsonSemAction *sem) { char *val = NULL; json_scalar_action sfunc = sem->scalar; char **valaddr; JsonTokenType tok = lex_peek(lex); valaddr = sfunc == NULL ? NULL : &val; /* a scalar must be a string, a number, true, false, or null */ switch (tok) { case JSON_TOKEN_TRUE: lex_accept(lex, JSON_TOKEN_TRUE, valaddr); break; case JSON_TOKEN_FALSE: lex_accept(lex, JSON_TOKEN_FALSE, valaddr); break; case JSON_TOKEN_NULL: lex_accept(lex, JSON_TOKEN_NULL, valaddr); break; case JSON_TOKEN_NUMBER: lex_accept(lex, JSON_TOKEN_NUMBER, valaddr); break; case JSON_TOKEN_STRING: lex_accept(lex, JSON_TOKEN_STRING, valaddr); break; default: report_parse_error(JSON_PARSE_VALUE, lex); } if (sfunc != NULL) (*sfunc) (sem->semstate, val, tok); } static void parse_object_field(JsonLexContext *lex, JsonSemAction *sem) { /* * An object field is "fieldname" : value where value can be a scalar, * object or array. Note: in user-facing docs and error messages, we * generally call a field name a "key". */ char *fname = NULL; /* keep compiler quiet */ json_ofield_action ostart = sem->object_field_start; json_ofield_action oend = sem->object_field_end; bool isnull; char **fnameaddr = NULL; JsonTokenType tok; if (ostart != NULL || oend != NULL) fnameaddr = &fname; if (!lex_accept(lex, JSON_TOKEN_STRING, fnameaddr)) report_parse_error(JSON_PARSE_STRING, lex); lex_expect(JSON_PARSE_OBJECT_LABEL, lex, JSON_TOKEN_COLON); tok = lex_peek(lex); isnull = tok == JSON_TOKEN_NULL; if (ostart != NULL) (*ostart) (sem->semstate, fname, isnull); switch (tok) { case JSON_TOKEN_OBJECT_START: parse_object(lex, sem); break; case JSON_TOKEN_ARRAY_START: parse_array(lex, sem); break; default: parse_scalar(lex, sem); } if (oend != NULL) (*oend) (sem->semstate, fname, isnull); } static void parse_object(JsonLexContext *lex, JsonSemAction *sem) { /* * an object is a possibly empty sequence of object fields, separated by * commas and surrounded by curly braces. */ json_struct_action ostart = sem->object_start; json_struct_action oend = sem->object_end; JsonTokenType tok; check_stack_depth(); if (ostart != NULL) (*ostart) (sem->semstate); /* * Data inside an object is at a higher nesting level than the object * itself. Note that we increment this after we call the semantic routine * for the object start and restore it before we call the routine for the * object end. */ lex->lex_level++; /* we know this will succeed, just clearing the token */ lex_expect(JSON_PARSE_OBJECT_START, lex, JSON_TOKEN_OBJECT_START); tok = lex_peek(lex); switch (tok) { case JSON_TOKEN_STRING: parse_object_field(lex, sem); while (lex_accept(lex, JSON_TOKEN_COMMA, NULL)) parse_object_field(lex, sem); break; case JSON_TOKEN_OBJECT_END: break; default: /* case of an invalid initial token inside the object */ report_parse_error(JSON_PARSE_OBJECT_START, lex); } lex_expect(JSON_PARSE_OBJECT_NEXT, lex, JSON_TOKEN_OBJECT_END); lex->lex_level--; if (oend != NULL) (*oend) (sem->semstate); } static void parse_array_element(JsonLexContext *lex, JsonSemAction *sem) { json_aelem_action astart = sem->array_element_start; json_aelem_action aend = sem->array_element_end; JsonTokenType tok = lex_peek(lex); bool isnull; isnull = tok == JSON_TOKEN_NULL; if (astart != NULL) (*astart) (sem->semstate, isnull); /* an array element is any object, array or scalar */ switch (tok) { case JSON_TOKEN_OBJECT_START: parse_object(lex, sem); break; case JSON_TOKEN_ARRAY_START: parse_array(lex, sem); break; default: parse_scalar(lex, sem); } if (aend != NULL) (*aend) (sem->semstate, isnull); } static void parse_array(JsonLexContext *lex, JsonSemAction *sem) { /* * an array is a possibly empty sequence of array elements, separated by * commas and surrounded by square brackets. */ json_struct_action astart = sem->array_start; json_struct_action aend = sem->array_end; check_stack_depth(); if (astart != NULL) (*astart) (sem->semstate); /* * Data inside an array is at a higher nesting level than the array * itself. Note that we increment this after we call the semantic routine * for the array start and restore it before we call the routine for the * array end. */ lex->lex_level++; lex_expect(JSON_PARSE_ARRAY_START, lex, JSON_TOKEN_ARRAY_START); if (lex_peek(lex) != JSON_TOKEN_ARRAY_END) { parse_array_element(lex, sem); while (lex_accept(lex, JSON_TOKEN_COMMA, NULL)) parse_array_element(lex, sem); } lex_expect(JSON_PARSE_ARRAY_NEXT, lex, JSON_TOKEN_ARRAY_END); lex->lex_level--; if (aend != NULL) (*aend) (sem->semstate); } /* * Lex one token from the input stream. */ void json_lex(JsonLexContext *lex) { char *s; int len; /* Skip leading whitespace. */ s = lex->token_terminator; len = s - lex->input; while (len < lex->input_length && (*s == ' ' || *s == '\t' || *s == '\n' || *s == '\r')) { if (*s == '\n') ++lex->line_number; ++s; ++len; } lex->token_start = s; /* Determine token type. */ if (len >= lex->input_length) { lex->token_start = NULL; lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s; lex->token_type = JSON_TOKEN_END; } else switch (*s) { /* Single-character token, some kind of punctuation mark. */ case '{': lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; lex->token_type = JSON_TOKEN_OBJECT_START; break; case '}': lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; lex->token_type = JSON_TOKEN_OBJECT_END; break; case '[': lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; lex->token_type = JSON_TOKEN_ARRAY_START; break; case ']': lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; lex->token_type = JSON_TOKEN_ARRAY_END; break; case ',': lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; lex->token_type = JSON_TOKEN_COMMA; break; case ':': lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; lex->token_type = JSON_TOKEN_COLON; break; case '"': /* string */ json_lex_string(lex); lex->token_type = JSON_TOKEN_STRING; break; case '-': /* Negative number. */ json_lex_number(lex, s + 1, NULL, NULL); lex->token_type = JSON_TOKEN_NUMBER; break; case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9': /* Positive number. */ json_lex_number(lex, s, NULL, NULL); lex->token_type = JSON_TOKEN_NUMBER; break; default: { char *p; /* * We're not dealing with a string, number, legal * punctuation mark, or end of string. The only legal * tokens we might find here are true, false, and null, * but for error reporting purposes we scan until we see a * non-alphanumeric character. That way, we can report * the whole word as an unexpected token, rather than just * some unintuitive prefix thereof. */ for (p = s; p - s < lex->input_length - len && JSON_ALPHANUMERIC_CHAR(*p); p++) /* skip */ ; /* * We got some sort of unexpected punctuation or an * otherwise unexpected character, so just complain about * that one character. */ if (p == s) { lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; report_invalid_token(lex); } /* * We've got a real alphanumeric token here. If it * happens to be true, false, or null, all is well. If * not, error out. */ lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = p; if (p - s == 4) { if (memcmp(s, "true", 4) == 0) lex->token_type = JSON_TOKEN_TRUE; else if (memcmp(s, "null", 4) == 0) lex->token_type = JSON_TOKEN_NULL; else report_invalid_token(lex); } else if (p - s == 5 && memcmp(s, "false", 5) == 0) lex->token_type = JSON_TOKEN_FALSE; else report_invalid_token(lex); } } /* end of switch */ } /* * The next token in the input stream is known to be a string; lex it. */ static inline void json_lex_string(JsonLexContext *lex) { char *s; int len; int hi_surrogate = -1; if (lex->strval != NULL) resetStringInfo(lex->strval); Assert(lex->input_length > 0); s = lex->token_start; len = lex->token_start - lex->input; for (;;) { s++; len++; /* Premature end of the string. */ if (len >= lex->input_length) { lex->token_terminator = s; report_invalid_token(lex); } else if (*s == '"') break; else if ((unsigned char) *s < 32) { /* Per RFC4627, these characters MUST be escaped. */ /* Since *s isn't printable, exclude it from the context string */ lex->token_terminator = s; ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Character with value 0x%02x must be escaped.", (unsigned char) *s), report_json_context(lex))); } else if (*s == '\\') { /* OK, we have an escape character. */ s++; len++; if (len >= lex->input_length) { lex->token_terminator = s; report_invalid_token(lex); } else if (*s == 'u') { int i; int ch = 0; for (i = 1; i <= 4; i++) { s++; len++; if (len >= lex->input_length) { lex->token_terminator = s; report_invalid_token(lex); } else if (*s >= '0' && *s <= '9') ch = (ch * 16) + (*s - '0'); else if (*s >= 'a' && *s <= 'f') ch = (ch * 16) + (*s - 'a') + 10; else if (*s >= 'A' && *s <= 'F') ch = (ch * 16) + (*s - 'A') + 10; else { lex->token_terminator = s + pg_mblen(s); ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("\"\\u\" must be followed by four hexadecimal digits."), report_json_context(lex))); } } if (lex->strval != NULL) { char utf8str[5]; int utf8len; if (ch >= 0xd800 && ch <= 0xdbff) { if (hi_surrogate != -1) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Unicode high surrogate must not follow a high surrogate."), report_json_context(lex))); hi_surrogate = (ch & 0x3ff) << 10; continue; } else if (ch >= 0xdc00 && ch <= 0xdfff) { if (hi_surrogate == -1) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Unicode low surrogate must follow a high surrogate."), report_json_context(lex))); ch = 0x10000 + hi_surrogate + (ch & 0x3ff); hi_surrogate = -1; } if (hi_surrogate != -1) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Unicode low surrogate must follow a high surrogate."), report_json_context(lex))); /* * For UTF8, replace the escape sequence by the actual * utf8 character in lex->strval. Do this also for other * encodings if the escape designates an ASCII character, * otherwise raise an error. */ if (ch == 0) { /* We can't allow this, since our TEXT type doesn't */ ereport(ERROR, (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER), errmsg("unsupported Unicode escape sequence"), errdetail("\\u0000 cannot be converted to text."), report_json_context(lex))); } else if (GetDatabaseEncoding() == PG_UTF8) { unicode_to_utf8(ch, (unsigned char *) utf8str); utf8len = pg_utf_mblen((unsigned char *) utf8str); appendBinaryStringInfo(lex->strval, utf8str, utf8len); } else if (ch <= 0x007f) { /* * This is the only way to designate things like a * form feed character in JSON, so it's useful in all * encodings. */ appendStringInfoChar(lex->strval, (char) ch); } else { ereport(ERROR, (errcode(ERRCODE_UNTRANSLATABLE_CHARACTER), errmsg("unsupported Unicode escape sequence"), errdetail("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8."), report_json_context(lex))); } } } else if (lex->strval != NULL) { if (hi_surrogate != -1) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Unicode low surrogate must follow a high surrogate."), report_json_context(lex))); switch (*s) { case '"': case '\\': case '/': appendStringInfoChar(lex->strval, *s); break; case 'b': appendStringInfoChar(lex->strval, '\b'); break; case 'f': appendStringInfoChar(lex->strval, '\f'); break; case 'n': appendStringInfoChar(lex->strval, '\n'); break; case 'r': appendStringInfoChar(lex->strval, '\r'); break; case 't': appendStringInfoChar(lex->strval, '\t'); break; default: /* Not a valid string escape, so error out. */ lex->token_terminator = s + pg_mblen(s); ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Escape sequence \"\\%s\" is invalid.", extract_mb_char(s)), report_json_context(lex))); } } else if (strchr("\"\\/bfnrt", *s) == NULL) { /* * Simpler processing if we're not bothered about de-escaping * * It's very tempting to remove the strchr() call here and * replace it with a switch statement, but testing so far has * shown it's not a performance win. */ lex->token_terminator = s + pg_mblen(s); ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Escape sequence \"\\%s\" is invalid.", extract_mb_char(s)), report_json_context(lex))); } } else if (lex->strval != NULL) { if (hi_surrogate != -1) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Unicode low surrogate must follow a high surrogate."), report_json_context(lex))); appendStringInfoChar(lex->strval, *s); } } if (hi_surrogate != -1) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Unicode low surrogate must follow a high surrogate."), report_json_context(lex))); /* Hooray, we found the end of the string! */ lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s + 1; } /* * The next token in the input stream is known to be a number; lex it. * * In JSON, a number consists of four parts: * * (1) An optional minus sign ('-'). * * (2) Either a single '0', or a string of one or more digits that does not * begin with a '0'. * * (3) An optional decimal part, consisting of a period ('.') followed by * one or more digits. (Note: While this part can be omitted * completely, it's not OK to have only the decimal point without * any digits afterwards.) * * (4) An optional exponent part, consisting of 'e' or 'E', optionally * followed by '+' or '-', followed by one or more digits. (Note: * As with the decimal part, if 'e' or 'E' is present, it must be * followed by at least one digit.) * * The 's' argument to this function points to the ostensible beginning * of part 2 - i.e. the character after any optional minus sign, or the * first character of the string if there is none. * * If num_err is not NULL, we return an error flag to *num_err rather than * raising an error for a badly-formed number. Also, if total_len is not NULL * the distance from lex->input to the token end+1 is returned to *total_len. */ static inline void json_lex_number(JsonLexContext *lex, char *s, bool *num_err, int *total_len) { bool error = false; int len = s - lex->input; /* Part (1): leading sign indicator. */ /* Caller already did this for us; so do nothing. */ /* Part (2): parse main digit string. */ if (len < lex->input_length && *s == '0') { s++; len++; } else if (len < lex->input_length && *s >= '1' && *s <= '9') { do { s++; len++; } while (len < lex->input_length && *s >= '0' && *s <= '9'); } else error = true; /* Part (3): parse optional decimal portion. */ if (len < lex->input_length && *s == '.') { s++; len++; if (len == lex->input_length || *s < '0' || *s > '9') error = true; else { do { s++; len++; } while (len < lex->input_length && *s >= '0' && *s <= '9'); } } /* Part (4): parse optional exponent. */ if (len < lex->input_length && (*s == 'e' || *s == 'E')) { s++; len++; if (len < lex->input_length && (*s == '+' || *s == '-')) { s++; len++; } if (len == lex->input_length || *s < '0' || *s > '9') error = true; else { do { s++; len++; } while (len < lex->input_length && *s >= '0' && *s <= '9'); } } /* * Check for trailing garbage. As in json_lex(), any alphanumeric stuff * here should be considered part of the token for error-reporting * purposes. */ for (; len < lex->input_length && JSON_ALPHANUMERIC_CHAR(*s); s++, len++) error = true; if (total_len != NULL) *total_len = len; if (num_err != NULL) { /* let the caller handle any error */ *num_err = error; } else { /* return token endpoint */ lex->prev_token_terminator = lex->token_terminator; lex->token_terminator = s; /* handle error if any */ if (error) report_invalid_token(lex); } } /* * Report a parse error. * * lex->token_start and lex->token_terminator must identify the current token. */ static void report_parse_error(JsonParseContext ctx, JsonLexContext *lex) { char *token; int toklen; /* Handle case where the input ended prematurely. */ if (lex->token_start == NULL || lex->token_type == JSON_TOKEN_END) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("The input string ended unexpectedly."), report_json_context(lex))); /* Separate out the current token. */ toklen = lex->token_terminator - lex->token_start; token = palloc(toklen + 1); memcpy(token, lex->token_start, toklen); token[toklen] = '\0'; /* Complain, with the appropriate detail message. */ if (ctx == JSON_PARSE_END) ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected end of input, but found \"%s\".", token), report_json_context(lex))); else { switch (ctx) { case JSON_PARSE_VALUE: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected JSON value, but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_STRING: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected string, but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_ARRAY_START: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected array element or \"]\", but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_ARRAY_NEXT: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected \",\" or \"]\", but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_OBJECT_START: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected string or \"}\", but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_OBJECT_LABEL: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected \":\", but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_OBJECT_NEXT: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected \",\" or \"}\", but found \"%s\".", token), report_json_context(lex))); break; case JSON_PARSE_OBJECT_COMMA: ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Expected string, but found \"%s\".", token), report_json_context(lex))); break; default: elog(ERROR, "unexpected json parse state: %d", ctx); } } } /* * Report an invalid input token. * * lex->token_start and lex->token_terminator must identify the token. */ static void report_invalid_token(JsonLexContext *lex) { char *token; int toklen; /* Separate out the offending token. */ toklen = lex->token_terminator - lex->token_start; token = palloc(toklen + 1); memcpy(token, lex->token_start, toklen); token[toklen] = '\0'; ereport(ERROR, (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), errmsg("invalid input syntax for type %s", "json"), errdetail("Token \"%s\" is invalid.", token), report_json_context(lex))); } /* * Report a CONTEXT line for bogus JSON input. * * lex->token_terminator must be set to identify the spot where we detected * the error. Note that lex->token_start might be NULL, in case we recognized * error at EOF. * * The return value isn't meaningful, but we make it non-void so that this * can be invoked inside ereport(). */ static int report_json_context(JsonLexContext *lex) { const char *context_start; const char *context_end; const char *line_start; int line_number; char *ctxt; int ctxtlen; const char *prefix; const char *suffix; /* Choose boundaries for the part of the input we will display */ context_start = lex->input; context_end = lex->token_terminator; line_start = context_start; line_number = 1; for (;;) { /* Always advance over newlines */ if (context_start < context_end && *context_start == '\n') { context_start++; line_start = context_start; line_number++; continue; } /* Otherwise, done as soon as we are close enough to context_end */ if (context_end - context_start < 50) break; /* Advance to next multibyte character */ if (IS_HIGHBIT_SET(*context_start)) context_start += pg_mblen(context_start); else context_start++; } /* * We add "..." to indicate that the excerpt doesn't start at the * beginning of the line ... but if we're within 3 characters of the * beginning of the line, we might as well just show the whole line. */ if (context_start - line_start <= 3) context_start = line_start; /* Get a null-terminated copy of the data to present */ ctxtlen = context_end - context_start; ctxt = palloc(ctxtlen + 1); memcpy(ctxt, context_start, ctxtlen); ctxt[ctxtlen] = '\0'; /* * Show the context, prefixing "..." if not starting at start of line, and * suffixing "..." if not ending at end of line. */ prefix = (context_start > line_start) ? "..." : ""; suffix = (lex->token_type != JSON_TOKEN_END && context_end - lex->input < lex->input_length && *context_end != '\n' && *context_end != '\r') ? "..." : ""; return errcontext("JSON data, line %d: %s%s%s", line_number, prefix, ctxt, suffix); } /* * Extract a single, possibly multi-byte char from the input string. */ static char * extract_mb_char(char *s) { char *res; int len; len = pg_mblen(s); res = palloc(len + 1); memcpy(res, s, len); res[len] = '\0'; return res; }