Fix encoding of empty input by DOT filter.

* libmailutils/filter/dot.c (_dot_encoder): Don't emit additional
empty line on empty input (i.e. if mu_filter_lastbuf arrives when
dfa is in dot_encode_init state).
* libmailutils/tests/dot.at: Test empty input.

3 files changed, 11 insertions, 2 deletions

diff --git a/libmailutils/filter/dot.c b/libmailutils/filter/dot.c
index 1e41df12c..d3a3aab34 100644
--- a/libmailutils/filter/dot.c
+++ b/libmailutils/filter/dot.c
@@ -178,7 +178,7 @@ _dot_encoder (void *xd,
   size_t isize;
   char *optr;
   size_t osize;
-  int *state = xd;
+  enum dot_encode_state *state = xd;
   
   switch (cmd)
     {
@@ -229,6 +229,7 @@ _dot_encoder (void *xd,
     {
       switch (*state)
         {
+        case dot_encode_init:
         case dot_encode_lf:
           if (j + 2 > osize)
             result = mu_filter_again;
diff --git a/libmailutils/tests/dot.at b/libmailutils/tests/dot.at
index 1516a1bf8..7be7bb6b2 100644
--- a/libmailutils/tests/dot.at
+++ b/libmailutils/tests/dot.at
@@ -48,6 +48,14 @@ end.
 ])
 AT_CLEANUP
 
+AT_SETUP([DOT empty input])
+AT_KEYWORDS([DOT empty input])
+AT_CHECK([fltst dot encode read < /dev/null],
+[0],
+[.
+])
+AT_CLEANUP
+
 AT_SETUP([DOT reversibility])
 AT_KEYWORDS([filter dot])
 AT_CHECK([
diff --git a/libmailutils/tests/testsuite.at b/libmailutils/tests/testsuite.at
index db284fd86..5e302ee6a 100644
--- a/libmailutils/tests/testsuite.at
+++ b/libmailutils/tests/testsuite.at
@@ -215,9 +215,9 @@ m4_include([hdrcpy.at])
 m4_include([linecon.at])
 m4_include([htmlent.at])
 m4_include([xml.at])
+m4_include([dot.at])
 m4_include([crlf.at])
 m4_include([crlfdot.at])
-m4_include([dot.at])
 
 AT_BANNER(Debug Specification)
 m4_include([debugspec.at])