Allow clobbering of a PerlIO::Scalar and more tests

Message-ID: <Pine.LNX.4.21.0105031508360.805-100000@marmot.rim.canoe.ca>

p4raw-id: //depot/perl@9981

diff --git a/ext/PerlIO/Scalar/Scalar.xs b/ext/PerlIO/Scalar/Scalar.xs
index 9e9412a..a4203bf 100644 (file)
--- a/ext/PerlIO/Scalar/Scalar.xs
+++ b/ext/PerlIO/Scalar/Scalar.xs
@@ -44,6 +44,8 @@ PerlIOScalar_pushed(PerlIO *f, const char *mode, SV *arg)
    s->posn = SvCUR(SvRV(arg));
  else
    s->posn = 0;
+ if ((PerlIOBase(f)->flags) & PERLIO_F_TRUNCATE)
+   SvCUR(SvRV(arg)) = 0;
  return code;
 }
 

diff --git a/t/lib/io_scalar.t b/t/lib/io_scalar.t
index 928355e..14bbf4d 100644 (file)
--- a/t/lib/io_scalar.t
+++ b/t/lib/io_scalar.t
@@ -10,7 +10,7 @@ BEGIN {
 }
 
 $| = 1;
-print "1..11\n";
+print "1..19\n";
 
 my $fh;
 my $var = "ok 2\n";
@@ -32,17 +32,57 @@ print "not " if eof($fh);
 print "ok 8\n";
 print "not " unless <$fh> eq "foo\n";
 print "ok 9\n";
-# Test multiple consecutive writes to $var
-$var = "";
-seek($fh, 0, 0);
-print $fh "Fred and Wilma ";
-print $fh "Flintstone";
-print "not " unless $var eq "Fred and Wilma Flintstone";
+my $rv = close $fh;
+if (!$rv) {
+    print "# Close on scalar failed: $!\n";
+    print "not ";
+}
 print "ok 10\n";
-# Test appending
+
+# Test that semantics are similar to normal file-based I/O
+# Check that ">" clobbers the scalar
+$var = "Something";
+open $fh, ">", \$var;
+print "# Got [$var], expect []\n";
+print "not " unless $var eq "";
+print "ok 11\n";
+#  Check that file offset set to beginning of scalar
+my $off = tell($fh);
+print "# Got $off, expect 0\n";
+print "not " unless $off == 0;
+print "ok 12\n";
+# Check that writes go where they should and update the offset
+$var = "Something";
+print $fh "Brea";
+$off = tell($fh);
+print "# Got $off, expect 4\n";
+print "not " unless $off == 4;
+print "ok 13\n";
+print "# Got [$var], expect [Breathing]\n";
+print "not " unless $var eq "Breathing";
+print "ok 14\n";
 close $fh;
-$var = "Fred and Wilma ";
+
+# Check that ">>" appends to the scalar
+$var = "Something ";
 open $fh, ">>", \$var;
-print $fh "Flintstone";
-print "not " unless $var eq "Fred and Wilma Flintstone";
-print "ok 11\n";
+$off = tell($fh);
+print "# Got $off, expect 10\n";
+print "not " unless $off == 10;
+print "ok 15\n";
+print "# Got [$var], expect [Something ]\n";
+print "not " unless $var eq "Something ";
+print "ok 16\n";
+#  Check that further writes go to the very end of the scalar
+$var .= "else ";
+print "# Got [$var], expect [Something else ]\n";
+print "not " unless $var eq "Something else ";
+print "ok 17\n";
+$off = tell($fh);
+print "# Got $off, expect 10\n";
+print "not " unless $off == 10;
+print "ok 18\n";
+print $fh "is here";
+print "# Got [$var], expect [Something else is here]\n";
+print "not " unless $var eq "Something else is here";
+print "ok 19\n";