diff options
Diffstat (limited to 'src/backend/utils/adt/jsonpath_scan.l')
| -rw-r--r-- | src/backend/utils/adt/jsonpath_scan.l | 638 |
1 files changed, 638 insertions, 0 deletions
diff --git a/src/backend/utils/adt/jsonpath_scan.l b/src/backend/utils/adt/jsonpath_scan.l new file mode 100644 index 00000000000..110ea2160d9 --- /dev/null +++ b/src/backend/utils/adt/jsonpath_scan.l @@ -0,0 +1,638 @@ +/*------------------------------------------------------------------------- + * + * jsonpath_scan.l + * Lexical parser for jsonpath datatype + * + * Copyright (c) 2019, PostgreSQL Global Development Group + * + * IDENTIFICATION + * src/backend/utils/adt/jsonpath_scan.l + * + *------------------------------------------------------------------------- + */ + +%{ +#include "postgres.h" + +#include "mb/pg_wchar.h" +#include "nodes/pg_list.h" +#include "utils/jsonpath_scanner.h" + +static string scanstring; + +/* No reason to constrain amount of data slurped */ +/* #define YY_READ_BUF_SIZE 16777216 */ + +/* Handles to the buffer that the lexer uses internally */ +static YY_BUFFER_STATE scanbufhandle; +static char *scanbuf; +static int scanbuflen; + +static void addstring(bool init, char *s, int l); +static void addchar(bool init, char s); +static int checkSpecialVal(void); /* examine scanstring for the special + * value */ + +static void parseUnicode(char *s, int l); +static void parseHexChars(char *s, int l); + +/* Avoid exit() on fatal scanner errors (a bit ugly -- see yy_fatal_error) */ +#undef fprintf +#define fprintf(file, fmt, msg) fprintf_to_ereport(fmt, msg) + +static void +fprintf_to_ereport(const char *fmt, const char *msg) +{ + ereport(ERROR, (errmsg_internal("%s", msg))); +} + +#define yyerror jsonpath_yyerror +%} + +%option 8bit +%option never-interactive +%option nodefault +%option noinput +%option nounput +%option noyywrap +%option warn +%option prefix="jsonpath_yy" +%option bison-bridge +%option noyyalloc +%option noyyrealloc +%option noyyfree + +%x xQUOTED +%x xNONQUOTED +%x xVARQUOTED +%x xSINGLEQUOTED +%x xCOMMENT + +special [\?\%\$\.\[\]\{\}\(\)\|\&\!\=\<\>\@\#\,\*:\-\+\/] +any [^\?\%\$\.\[\]\{\}\(\)\|\&\!\=\<\>\@\#\,\*:\-\+\/\\\"\' \t\n\r\f] +blank [ \t\n\r\f] +hex_dig [0-9A-Fa-f] +unicode \\u({hex_dig}{4}|\{{hex_dig}{1,6}\}) +hex_char \\x{hex_dig}{2} + + +%% + +<INITIAL>\&\& { return AND_P; } + +<INITIAL>\|\| { return OR_P; } + +<INITIAL>\! { return NOT_P; } + +<INITIAL>\*\* { return ANY_P; } + +<INITIAL>\< { return LESS_P; } + +<INITIAL>\<\= { return LESSEQUAL_P; } + +<INITIAL>\=\= { return EQUAL_P; } + +<INITIAL>\<\> { return NOTEQUAL_P; } + +<INITIAL>\!\= { return NOTEQUAL_P; } + +<INITIAL>\>\= { return GREATEREQUAL_P; } + +<INITIAL>\> { return GREATER_P; } + +<INITIAL>\${any}+ { + addstring(true, yytext + 1, yyleng - 1); + addchar(false, '\0'); + yylval->str = scanstring; + return VARIABLE_P; + } + +<INITIAL>\$\" { + addchar(true, '\0'); + BEGIN xVARQUOTED; + } + +<INITIAL>{special} { return *yytext; } + +<INITIAL>{blank}+ { /* ignore */ } + +<INITIAL>\/\* { + addchar(true, '\0'); + BEGIN xCOMMENT; + } + +<INITIAL>[0-9]+(\.[0-9]+)?[eE][+-]?[0-9]+ /* float */ { + addstring(true, yytext, yyleng); + addchar(false, '\0'); + yylval->str = scanstring; + return NUMERIC_P; + } + +<INITIAL>\.[0-9]+[eE][+-]?[0-9]+ /* float */ { + addstring(true, yytext, yyleng); + addchar(false, '\0'); + yylval->str = scanstring; + return NUMERIC_P; + } + +<INITIAL>([0-9]+)?\.[0-9]+ { + addstring(true, yytext, yyleng); + addchar(false, '\0'); + yylval->str = scanstring; + return NUMERIC_P; + } + +<INITIAL>[0-9]+ { + addstring(true, yytext, yyleng); + addchar(false, '\0'); + yylval->str = scanstring; + return INT_P; + } + +<INITIAL>{any}+ { + addstring(true, yytext, yyleng); + BEGIN xNONQUOTED; + } + +<INITIAL>\" { + addchar(true, '\0'); + BEGIN xQUOTED; + } + +<INITIAL>\' { + addchar(true, '\0'); + BEGIN xSINGLEQUOTED; + } + +<INITIAL>\\ { + yyless(0); + addchar(true, '\0'); + BEGIN xNONQUOTED; + } + +<xNONQUOTED>{any}+ { + addstring(false, yytext, yyleng); + } + +<xNONQUOTED>{blank}+ { + yylval->str = scanstring; + BEGIN INITIAL; + return checkSpecialVal(); + } + + +<xNONQUOTED>\/\* { + yylval->str = scanstring; + BEGIN xCOMMENT; + } + +<xNONQUOTED>({special}|\"|\') { + yylval->str = scanstring; + yyless(0); + BEGIN INITIAL; + return checkSpecialVal(); + } + +<xNONQUOTED><<EOF>> { + yylval->str = scanstring; + BEGIN INITIAL; + return checkSpecialVal(); + } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\[\"\'\\] { addchar(false, yytext[1]); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\b { addchar(false, '\b'); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\f { addchar(false, '\f'); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\n { addchar(false, '\n'); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\r { addchar(false, '\r'); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\t { addchar(false, '\t'); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\v { addchar(false, '\v'); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{unicode}+ { parseUnicode(yytext, yyleng); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>{hex_char}+ { parseHexChars(yytext, yyleng); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\x { yyerror(NULL, "Hex character sequence is invalid"); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\u { yyerror(NULL, "Unicode sequence is invalid"); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\. { yyerror(NULL, "Escape sequence is invalid"); } + +<xNONQUOTED,xQUOTED,xVARQUOTED,xSINGLEQUOTED>\\ { yyerror(NULL, "Unexpected end after backslash"); } + +<xQUOTED,xVARQUOTED,xSINGLEQUOTED><<EOF>> { yyerror(NULL, "Unexpected end of quoted string"); } + +<xQUOTED>\" { + yylval->str = scanstring; + BEGIN INITIAL; + return STRING_P; + } + +<xVARQUOTED>\" { + yylval->str = scanstring; + BEGIN INITIAL; + return VARIABLE_P; + } + +<xSINGLEQUOTED>\' { + yylval->str = scanstring; + BEGIN INITIAL; + return STRING_P; + } + +<xQUOTED,xVARQUOTED>[^\\\"]+ { addstring(false, yytext, yyleng); } + +<xSINGLEQUOTED>[^\\\']+ { addstring(false, yytext, yyleng); } + +<INITIAL><<EOF>> { yyterminate(); } + +<xCOMMENT>\*\/ { BEGIN INITIAL; } + +<xCOMMENT>[^\*]+ { } + +<xCOMMENT>\* { } + +<xCOMMENT><<EOF>> { yyerror(NULL, "Unexpected end of comment"); } + +%% + +void +jsonpath_yyerror(JsonPathParseResult **result, const char *message) +{ + if (*yytext == YY_END_OF_BUFFER_CHAR) + { + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("bad jsonpath representation"), + /* translator: %s is typically "syntax error" */ + errdetail("%s at end of input", message))); + } + else + { + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("bad jsonpath representation"), + /* translator: first %s is typically "syntax error" */ + errdetail("%s at or near \"%s\"", message, yytext))); + } +} + +typedef struct keyword +{ + int16 len; + bool lowercase; + int val; + char *keyword; +} keyword; + +/* + * Array of key words should be sorted by length and then + * alphabetical order + */ + +static keyword keywords[] = { + { 2, false, IS_P, "is"}, + { 2, false, TO_P, "to"}, + { 3, false, ABS_P, "abs"}, + { 3, false, LAX_P, "lax"}, + { 4, false, FLAG_P, "flag"}, + { 4, false, LAST_P, "last"}, + { 4, true, NULL_P, "null"}, + { 4, false, SIZE_P, "size"}, + { 4, true, TRUE_P, "true"}, + { 4, false, TYPE_P, "type"}, + { 4, false, WITH_P, "with"}, + { 5, true, FALSE_P, "false"}, + { 5, false, FLOOR_P, "floor"}, + { 6, false, DOUBLE_P, "double"}, + { 6, false, EXISTS_P, "exists"}, + { 6, false, STARTS_P, "starts"}, + { 6, false, STRICT_P, "strict"}, + { 7, false, CEILING_P, "ceiling"}, + { 7, false, UNKNOWN_P, "unknown"}, + { 8, false, KEYVALUE_P, "keyvalue"}, + { 10,false, LIKE_REGEX_P, "like_regex"}, +}; + +static int +checkSpecialVal() +{ + int res = IDENT_P; + int diff; + keyword *StopLow = keywords, + *StopHigh = keywords + lengthof(keywords), + *StopMiddle; + + if (scanstring.len > keywords[lengthof(keywords) - 1].len) + return res; + + while(StopLow < StopHigh) + { + StopMiddle = StopLow + ((StopHigh - StopLow) >> 1); + + if (StopMiddle->len == scanstring.len) + diff = pg_strncasecmp(StopMiddle->keyword, scanstring.val, + scanstring.len); + else + diff = StopMiddle->len - scanstring.len; + + if (diff < 0) + StopLow = StopMiddle + 1; + else if (diff > 0) + StopHigh = StopMiddle; + else + { + if (StopMiddle->lowercase) + diff = strncmp(StopMiddle->keyword, scanstring.val, + scanstring.len); + + if (diff == 0) + res = StopMiddle->val; + + break; + } + } + + return res; +} + +/* + * Called before any actual parsing is done + */ +static void +jsonpath_scanner_init(const char *str, int slen) +{ + if (slen <= 0) + slen = strlen(str); + + /* + * Might be left over after ereport() + */ + yy_init_globals(); + + /* + * Make a scan buffer with special termination needed by flex. + */ + + scanbuflen = slen; + scanbuf = palloc(slen + 2); + memcpy(scanbuf, str, slen); + scanbuf[slen] = scanbuf[slen + 1] = YY_END_OF_BUFFER_CHAR; + scanbufhandle = yy_scan_buffer(scanbuf, slen + 2); + + BEGIN(INITIAL); +} + + +/* + * Called after parsing is done to clean up after jsonpath_scanner_init() + */ +static void +jsonpath_scanner_finish(void) +{ + yy_delete_buffer(scanbufhandle); + pfree(scanbuf); +} + +static void +addstring(bool init, char *s, int l) +{ + if (init) + { + scanstring.total = 32; + scanstring.val = palloc(scanstring.total); + scanstring.len = 0; + } + + if (s && l) + { + while(scanstring.len + l + 1 >= scanstring.total) + { + scanstring.total *= 2; + scanstring.val = repalloc(scanstring.val, scanstring.total); + } + + memcpy(scanstring.val + scanstring.len, s, l); + scanstring.len += l; + } +} + +static void +addchar(bool init, char s) +{ + if (init) + { + scanstring.total = 32; + scanstring.val = palloc(scanstring.total); + scanstring.len = 0; + } + else if(scanstring.len + 1 >= scanstring.total) + { + scanstring.total *= 2; + scanstring.val = repalloc(scanstring.val, scanstring.total); + } + + scanstring.val[ scanstring.len ] = s; + if (s != '\0') + scanstring.len++; +} + +JsonPathParseResult * +parsejsonpath(const char *str, int len) +{ + JsonPathParseResult *parseresult; + + jsonpath_scanner_init(str, len); + + if (jsonpath_yyparse((void*)&parseresult) != 0) + jsonpath_yyerror(NULL, "bugus input"); + + jsonpath_scanner_finish(); + + return parseresult; +} + +static int +hexval(char c) +{ + if (c >= '0' && c <= '9') + return c - '0'; + if (c >= 'a' && c <= 'f') + return c - 'a' + 0xA; + if (c >= 'A' && c <= 'F') + return c - 'A' + 0xA; + elog(ERROR, "invalid hexadecimal digit"); + return 0; /* not reached */ +} + +static void +addUnicodeChar(int ch) +{ + /* + * 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."))); + } + else if (GetDatabaseEncoding() == PG_UTF8) + { + char utf8str[5]; + int utf8len; + + unicode_to_utf8(ch, (unsigned char *) utf8str); + utf8len = pg_utf_mblen((unsigned char *) utf8str); + addstring(false, 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. + */ + addchar(false, (char) ch); + } + else + { + ereport(ERROR, + (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), + errmsg("invalid input syntax for type jsonpath"), + errdetail("Unicode escape values cannot be used for code " + "point values above 007F when the server encoding " + "is not UTF8."))); + } +} + +static void +addUnicode(int ch, int *hi_surrogate) +{ + if (ch >= 0xd800 && ch <= 0xdbff) + { + if (*hi_surrogate != -1) + ereport(ERROR, + (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), + errmsg("invalid input syntax for type jsonpath"), + errdetail("Unicode high surrogate must not follow " + "a high surrogate."))); + *hi_surrogate = (ch & 0x3ff) << 10; + return; + } + else if (ch >= 0xdc00 && ch <= 0xdfff) + { + if (*hi_surrogate == -1) + ereport(ERROR, + (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), + errmsg("invalid input syntax for type jsonpath"), + errdetail("Unicode low surrogate must follow a high " + "surrogate."))); + ch = 0x10000 + *hi_surrogate + (ch & 0x3ff); + *hi_surrogate = -1; + } + else if (*hi_surrogate != -1) + { + ereport(ERROR, + (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), + errmsg("invalid input syntax for type jsonpath"), + errdetail("Unicode low surrogate must follow a high " + "surrogate."))); + } + + addUnicodeChar(ch); +} + +/* + * parseUnicode was adopted from json_lex_string() in + * src/backend/utils/adt/json.c + */ +static void +parseUnicode(char *s, int l) +{ + int i; + int hi_surrogate = -1; + + for (i = 2; i < l; i += 2) /* skip '\u' */ + { + int ch = 0; + int j; + + if (s[i] == '{') /* parse '\u{XX...}' */ + { + while (s[++i] != '}' && i < l) + ch = (ch << 4) | hexval(s[i]); + i++; /* ski p '}' */ + } + else /* parse '\uXXXX' */ + { + for (j = 0; j < 4 && i < l; j++) + ch = (ch << 4) | hexval(s[i++]); + } + + addUnicode(ch, &hi_surrogate); + } + + if (hi_surrogate != -1) + { + ereport(ERROR, + (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), + errmsg("invalid input syntax for type jsonpath"), + errdetail("Unicode low surrogate must follow a high " + "surrogate."))); + } +} + +static void +parseHexChars(char *s, int l) +{ + int i; + + Assert(l % 4 /* \xXX */ == 0); + + for (i = 0; i < l / 4; i++) + { + int ch = (hexval(s[i * 4 + 2]) << 4) | hexval(s[i * 4 + 3]); + + addUnicodeChar(ch); + } +} + +/* + * Interface functions to make flex use palloc() instead of malloc(). + * It'd be better to make these static, but flex insists otherwise. + */ + +void * +jsonpath_yyalloc(yy_size_t bytes) +{ + return palloc(bytes); +} + +void * +jsonpath_yyrealloc(void *ptr, yy_size_t bytes) +{ + if (ptr) + return repalloc(ptr, bytes); + else + return palloc(bytes); +} + +void +jsonpath_yyfree(void *ptr) +{ + if (ptr) + pfree(ptr); +} + |