[Pidgin] #17232: improve smiley matching for unicode

[Pidgin]

#17232: improve smiley matching for unicode
--------------------+--------------------------
 Reporter:  gnubfx  |      Owner:
     Type:  patch   |     Status:  new
Milestone:  2.12.1  |  Component:  pidgin (gtk)
  Version:  2.12.0  |   Keywords:  smiley tree
--------------------+--------------------------
 Hi,

 smileys are matched by traversing a tree and trying to find the longest
 match. Comparison is bytewise. This works well for ASCII smiley-shortcuts,
 not as much for unicode because unicode characters tend to start with the
 same bytes. Example:

 {{{

 abc         ->    smiley1
 abcdef      ->    smiley2
 dxy         ->    smiley3

 }}}

 Now the expected behaviour for abcdxy would be to evaluate to
 (smiley1)(smiley3) but it only evaluates to (smiley3).

 I propose the matching routine to fall back to the last complete match,
 once a string stops matching:

 See pidgin/gtkimhtml.c from line 2056

 {{{
 --- old.c       2016-06-02 19:44:51.000000000 +0200
 +++ gtkimhtml.c 2017-07-24 20:23:56.619917000 +0200
 @@ -2056,7 +2056,8 @@
         const gchar *x = text;
         gint len = 0;
         const gchar *amp;
 -       gint alen;
 +       gint alen,
 +               lastlen = 0;

         while (*x) {
                 gchar *pos;
 @@ -2091,9 +2092,12 @@
                         pos = strchr (t->values->str, *x);
                 }

 -               if (pos)
 +               if (pos) {
                         t = t->children [GPOINTER_TO_INT(pos) -
 GPOINTER_TO_INT(t->values->str)];
 -               else
 +
 +                       if (t->image)
 +                               lastlen = len + alen;
 +               } else
                         break;

                 x += alen;
 @@ -2103,7 +2107,7 @@
         if (t->image)
                 return len;

 -       return 0;
 +       return lastlen;
  }
 }}}

--
Ticket URL: <https://developer.pidgin.im/ticket/17232>
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