Cope with more than 64K phrases in a thesaurus dictionary.

dict_thesaurus stored phrase IDs in uint16 fields, so it would get confused
and even crash if there were more than 64K entries in the configuration
file.  It turns out to be basically free to widen the phrase IDs to uint32,
so let's just do so.

This was complained of some time ago by David Boutin (in bug #7793);
he later submitted an informal patch but it was never acted on.
We now have another complaint (bug #11901 from Luc Ouellette) so it's
time to make something happen.

This is basically Boutin's patch, but for future-proofing I also added a
defense against too many words per phrase.  Note that we don't need any
explicit defense against overflow of the uint32 counters, since before that
happens we'd hit array allocation sizes that repalloc rejects.

Back-patch to all supported branches because of the crash risk.

diff --git a/src/backend/tsearch/dict_thesaurus.c b/src/backend/tsearch/dict_thesaurus.c
index fe4b8f41918ddf132dba550fbe2922e6b3665e5c..bb8132e98d72fbd3b66a3e602ab31217ecf22ab8 100644 (file)
--- a/src/backend/tsearch/dict_thesaurus.c
+++ b/src/backend/tsearch/dict_thesaurus.c
@@ -28,7 +28,7 @@
 
 typedef struct LexemeInfo
 {
-   uint16      idsubst;        /* entry's number in DictThesaurus->subst */
+   uint32      idsubst;        /* entry's number in DictThesaurus->subst */
    uint16      posinsubst;     /* pos info in entry */
    uint16      tnvariant;      /* total num lexemes in one variant */
    struct LexemeInfo *nextentry;
@@ -68,7 +68,7 @@ typedef struct
 
 
 static void
-newLexeme(DictThesaurus *d, char *b, char *e, uint16 idsubst, uint16 posinsubst)
+newLexeme(DictThesaurus *d, char *b, char *e, uint32 idsubst, uint16 posinsubst)
 {
    TheLexeme  *ptr;
 
@@ -102,7 +102,7 @@ newLexeme(DictThesaurus *d, char *b, char *e, uint16 idsubst, uint16 posinsubst)
 }
 
 static void
-addWrd(DictThesaurus *d, char *b, char *e, uint16 idsubst, uint16 nwrd, uint16 posinsubst, bool useasis)
+addWrd(DictThesaurus *d, char *b, char *e, uint32 idsubst, uint16 nwrd, uint16 posinsubst, bool useasis)
 {
    static int  nres = 0;
    static int  ntres = 0;
@@ -143,7 +143,6 @@ addWrd(DictThesaurus *d, char *b, char *e, uint16 idsubst, uint16 nwrd, uint16 p
            ntres *= 2;
            ptr->res = (TSLexeme *) repalloc(ptr->res, sizeof(TSLexeme) * ntres);
        }
-
    }
 
    ptr->res[nres].lexeme = palloc(e - b + 1);
@@ -168,7 +167,7 @@ static void
 thesaurusRead(char *filename, DictThesaurus *d)
 {
    tsearch_readline_state trst;
-   uint16      idsubst = 0;
+   uint32      idsubst = 0;
    bool        useasis = false;
    char       *line;
 
@@ -184,8 +183,8 @@ thesaurusRead(char *filename, DictThesaurus *d)
        char       *ptr;
        int         state = TR_WAITLEX;
        char       *beginwrd = NULL;
-       uint16      posinsubst = 0;
-       uint16      nwrd = 0;
+       uint32      posinsubst = 0;
+       uint32      nwrd = 0;
 
        ptr = line;
 
@@ -286,6 +285,16 @@ thesaurusRead(char *filename, DictThesaurus *d)
                    (errcode(ERRCODE_CONFIG_FILE_ERROR),
                     errmsg("unexpected end of line")));
 
+       /*
+        * Note: currently, tsearch_readline can't return lines exceeding 4KB,
+        * so overflow of the word counts is impossible.  But that may not
+        * always be true, so let's check.
+        */
+       if (nwrd != (uint16) nwrd || posinsubst != (uint16) posinsubst)
+           ereport(ERROR,
+                   (errcode(ERRCODE_CONFIG_FILE_ERROR),
+                    errmsg("too many lexemes in thesaurus entry")));
+
        pfree(line);
    }
 
@@ -670,7 +679,7 @@ findTheLexeme(DictThesaurus *d, char *lexeme)
 }
 
 static bool
-matchIdSubst(LexemeInfo *stored, uint16 idsubst)
+matchIdSubst(LexemeInfo *stored, uint32 idsubst)
 {
    bool        res = true;