diff options
Diffstat (limited to 'src/backend/parser/scan.l')
| -rw-r--r-- | src/backend/parser/scan.l | 131 |
1 files changed, 114 insertions, 17 deletions
diff --git a/src/backend/parser/scan.l b/src/backend/parser/scan.l index 84c73914a85..b1ea0cb5384 100644 --- a/src/backend/parser/scan.l +++ b/src/backend/parser/scan.l @@ -106,6 +106,18 @@ const uint16 ScanKeywordTokens[] = { */ #define ADVANCE_YYLLOC(delta) ( *(yylloc) += (delta) ) +/* + * Sometimes, we do want yylloc to point into the middle of a token; this is + * useful for instance to throw an error about an escape sequence within a + * string literal. But if we find no error there, we want to revert yylloc + * to the token start, so that that's the location reported to the parser. + * Use PUSH_YYLLOC/POP_YYLLOC to save/restore yylloc around such code. + * (Currently the implied "stack" is just one location, but someday we might + * need to nest these.) + */ +#define PUSH_YYLLOC() (yyextra->save_yylloc = *(yylloc)) +#define POP_YYLLOC() (*(yylloc) = yyextra->save_yylloc) + #define startlit() ( yyextra->literallen = 0 ) static void addlit(char *ytext, int yleng, core_yyscan_t yyscanner); static void addlitchar(unsigned char ychar, core_yyscan_t yyscanner); @@ -605,8 +617,18 @@ other . <xe>{xeunicode} { pg_wchar c = strtoul(yytext + 2, NULL, 16); + /* + * For consistency with other productions, issue any + * escape warning with cursor pointing to start of string. + * We might want to change that, someday. + */ check_escape_warning(yyscanner); + /* Remember start of overall string token ... */ + PUSH_YYLLOC(); + /* ... and set the error cursor to point at this esc seq */ + SET_YYLLOC(); + if (is_utf16_surrogate_first(c)) { yyextra->utf16_first_part = c; @@ -616,10 +638,18 @@ other . yyerror("invalid Unicode surrogate pair"); else addunicode(c, yyscanner); + + /* Restore yylloc to be start of string token */ + POP_YYLLOC(); } <xeu>{xeunicode} { pg_wchar c = strtoul(yytext + 2, NULL, 16); + /* Remember start of overall string token ... */ + PUSH_YYLLOC(); + /* ... and set the error cursor to point at this esc seq */ + SET_YYLLOC(); + if (!is_utf16_surrogate_second(c)) yyerror("invalid Unicode surrogate pair"); @@ -627,12 +657,21 @@ other . addunicode(c, yyscanner); + /* Restore yylloc to be start of string token */ + POP_YYLLOC(); + BEGIN(xe); } -<xeu>. { yyerror("invalid Unicode surrogate pair"); } -<xeu>\n { yyerror("invalid Unicode surrogate pair"); } -<xeu><<EOF>> { yyerror("invalid Unicode surrogate pair"); } +<xeu>. | +<xeu>\n | +<xeu><<EOF>> { + /* Set the error cursor to point at missing esc seq */ + SET_YYLLOC(); + yyerror("invalid Unicode surrogate pair"); + } <xe,xeu>{xeunicodefail} { + /* Set the error cursor to point at malformed esc seq */ + SET_YYLLOC(); ereport(ERROR, (errcode(ERRCODE_INVALID_ESCAPE_SEQUENCE), errmsg("invalid Unicode escape"), @@ -1029,12 +1068,13 @@ other . * scanner_errposition * Report a lexer or grammar error cursor position, if possible. * - * This is expected to be used within an ereport() call. The return value + * This is expected to be used within an ereport() call, or via an error + * callback such as setup_scanner_errposition_callback(). The return value * is a dummy (always 0, in fact). * * Note that this can only be used for messages emitted during raw parsing - * (essentially, scan.l and gram.y), since it requires the yyscanner struct - * to still be available. + * (essentially, scan.l, parser.c, and gram.y), since it requires the + * yyscanner struct to still be available. */ int scanner_errposition(int location, core_yyscan_t yyscanner) @@ -1051,6 +1091,62 @@ scanner_errposition(int location, core_yyscan_t yyscanner) } /* + * Error context callback for inserting scanner error location. + * + * Note that this will be called for *any* error occurring while the + * callback is installed. We avoid inserting an irrelevant error location + * if the error is a query cancel --- are there any other important cases? + */ +static void +scb_error_callback(void *arg) +{ + ScannerCallbackState *scbstate = (ScannerCallbackState *) arg; + + if (geterrcode() != ERRCODE_QUERY_CANCELED) + (void) scanner_errposition(scbstate->location, scbstate->yyscanner); +} + +/* + * setup_scanner_errposition_callback + * Arrange for non-scanner errors to report an error position + * + * Sometimes the scanner calls functions that aren't part of the scanner + * subsystem and can't reasonably be passed the yyscanner pointer; yet + * we would like any errors thrown in those functions to be tagged with an + * error location. Use this function to set up an error context stack + * entry that will accomplish that. Usage pattern: + * + * declare a local variable "ScannerCallbackState scbstate" + * ... + * setup_scanner_errposition_callback(&scbstate, yyscanner, location); + * call function that might throw error; + * cancel_scanner_errposition_callback(&scbstate); + */ +void +setup_scanner_errposition_callback(ScannerCallbackState *scbstate, + core_yyscan_t yyscanner, + int location) +{ + /* Setup error traceback support for ereport() */ + scbstate->yyscanner = yyscanner; + scbstate->location = location; + scbstate->errcallback.callback = scb_error_callback; + scbstate->errcallback.arg = (void *) scbstate; + scbstate->errcallback.previous = error_context_stack; + error_context_stack = &scbstate->errcallback; +} + +/* + * Cancel a previously-set-up errposition callback. + */ +void +cancel_scanner_errposition_callback(ScannerCallbackState *scbstate) +{ + /* Pop the error context stack */ + error_context_stack = scbstate->errcallback.previous; +} + +/* * scanner_yyerror * Report a lexer or grammar error. * @@ -1226,19 +1322,20 @@ process_integer_literal(const char *token, YYSTYPE *lval) static void addunicode(pg_wchar c, core_yyscan_t yyscanner) { - char buf[8]; + ScannerCallbackState scbstate; + char buf[MAX_UNICODE_EQUIVALENT_STRING + 1]; - /* See also check_unicode_value() in parser.c */ - if (c == 0 || c > 0x10FFFF) + if (!is_valid_unicode_codepoint(c)) yyerror("invalid Unicode escape value"); - if (c > 0x7F) - { - if (GetDatabaseEncoding() != PG_UTF8) - yyerror("Unicode escape values cannot be used for code point values above 007F when the server encoding is not UTF8"); - yyextra->saw_non_ascii = true; - } - unicode_to_utf8(c, (unsigned char *) buf); - addlit(buf, pg_mblen(buf), yyscanner); + + /* + * We expect that pg_unicode_to_server() will complain about any + * unconvertible code point, so we don't have to set saw_non_ascii. + */ + setup_scanner_errposition_callback(&scbstate, yyscanner, *(yylloc)); + pg_unicode_to_server(c, (unsigned char *) buf); + cancel_scanner_errposition_callback(&scbstate); + addlit(buf, strlen(buf), yyscanner); } static unsigned char |