Handle interaction of regexp's makesearch and MATCHALL more honestly.

Second thoughts about commit 824bf7190: we apply makesearch() to
an NFA after having determined whether it is a MATCHALL pattern.
Prepending ".*" doesn't make it non-MATCHALL, but it does change the
maximum possible match length, and makesearch() failed to update that.
This has no ill effects given the stylized usage of search NFAs, but
it seems like it's better to keep the data structure consistent.  In
particular, fixing this allows more honest handling of the MATCHALL
check in matchuntil(): we can now assert that maxmatchall is infinity,
instead of lamely assuming that it should act that way.

In passing, improve the code in dump[c]nfa so that infinite maxmatchall
is printed as "inf" not a magic number.

diff --git a/src/backend/regex/regc_nfa.c b/src/backend/regex/regc_nfa.c
index 059cf64df07a1c03fa4997779f6f609485d47485..60fb0bec5d7baf20f7a316a46468dcfdfc38bbbd 100644 (file)
--- a/src/backend/regex/regc_nfa.c
+++ b/src/backend/regex/regc_nfa.c
@@ -3660,8 +3660,13 @@ dumpnfa(struct nfa *nfa,
    if (nfa->flags & HASLACONS)
        fprintf(f, ", haslacons");
    if (nfa->flags & MATCHALL)
-       fprintf(f, ", minmatchall %d, maxmatchall %d",
-               nfa->minmatchall, nfa->maxmatchall);
+   {
+       fprintf(f, ", minmatchall %d", nfa->minmatchall);
+       if (nfa->maxmatchall == DUPINF)
+           fprintf(f, ", maxmatchall inf");
+       else
+           fprintf(f, ", maxmatchall %d", nfa->maxmatchall);
+   }
    fprintf(f, "\n");
    for (s = nfa->states; s != NULL; s = s->next)
    {
@@ -3824,8 +3829,13 @@ dumpcnfa(struct cnfa *cnfa,
    if (cnfa->flags & HASLACONS)
        fprintf(f, ", haslacons");
    if (cnfa->flags & MATCHALL)
-       fprintf(f, ", minmatchall %d, maxmatchall %d",
-               cnfa->minmatchall, cnfa->maxmatchall);
+   {
+       fprintf(f, ", minmatchall %d", cnfa->minmatchall);
+       if (cnfa->maxmatchall == DUPINF)
+           fprintf(f, ", maxmatchall inf");
+       else
+           fprintf(f, ", maxmatchall %d", cnfa->maxmatchall);
+   }
    fprintf(f, "\n");
    for (st = 0; st < cnfa->nstates; st++)
        dumpcstate(st, cnfa, f);

diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c
index d9840171a3393905ffada2e9c9dc63c951d73b2b..473738040bba478fd79e9f7d502138495ffd6473 100644 (file)
--- a/src/backend/regex/regcomp.c
+++ b/src/backend/regex/regcomp.c
@@ -599,6 +599,13 @@ makesearch(struct vars *v,
        /* and ^* and \A* too -- not always necessary, but harmless */
        newarc(nfa, PLAIN, nfa->bos[0], pre, pre);
        newarc(nfa, PLAIN, nfa->bos[1], pre, pre);
+
+       /*
+        * The pattern is still MATCHALL if it was before, but the max match
+        * length is now infinity.
+        */
+       if (nfa->flags & MATCHALL)
+           nfa->maxmatchall = DUPINF;
    }
 
    /*

diff --git a/src/backend/regex/rege_dfa.c b/src/backend/regex/rege_dfa.c
index 1d79d734468f94db502ad3db599cfbc5553134cf..ba1289c64a9553d622068046c0f2037ca6ecc486 100644 (file)
--- a/src/backend/regex/rege_dfa.c
+++ b/src/backend/regex/rege_dfa.c
@@ -385,14 +385,10 @@ matchuntil(struct vars *v,
    {
        size_t      nchr = probe - v->start;
 
-       /*
-        * It might seem that we should check maxmatchall too, but the .* at
-        * the front of the pattern absorbs any extra characters (and it was
-        * tacked on *after* computing minmatchall/maxmatchall).  Thus, we
-        * should match if there are at least minmatchall characters.
-        */
        if (nchr < d->cnfa->minmatchall)
            return 0;
+       /* maxmatchall will always be infinity, cf. makesearch() */
+       assert(d->cnfa->maxmatchall == DUPINF);
        return 1;
    }