On 2020-Aug-03, Asim Praveen wrote: > Thank you Alvaro for reviewing the patch! > > > On 01-Aug-2020, at 7:22 AM, Alvaro Herrera <alvhe...@2ndquadrant.com> wrote: > > > > What happens if a replacement string happens to be split in the middle > > by the fgets buffering? I think it'll fail to be replaced. This > > applies to both versions. > > Can a string to be replaced be split across multiple lines in the source > file? If I understand correctly, fgets reads one line from input file at a > time. If I do not, in the worst case, we will get an un-replaced string in > the output, such as “@abs_dir@“ and it should be easily detected by a failing > diff.
I meant what if the line is longer than 1023 chars and the replace marker starts at byte 1021, for example. Then the first fgets would get "@ab" and the second fgets would get "s_dir@" and none would see it as replaceable. > > In the stringinfo version it seemed to me that using pnstrdup is > > possible to avoid copying trailing bytes. > > That’s a good suggestion. Using pnstrdup would look like this: > > --- a/src/test/regress/pg_regress.c > +++ b/src/test/regress/pg_regress.c > @@ -465,7 +465,7 @@ replace_stringInfo(StringInfo string, const char > *replace, const char *replaceme > > while ((ptr = strstr(string->data, replace)) != NULL) > { > - char *dup = pg_strdup(string->data); > + char *dup = pnstrdup(string->data, string->maxlen); I was thinking pnstrdup(string->data, ptr - string->data) to avoid copying the chars beyond ptr. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services