X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Flanguage%2Fdictionary%2Fdelete-variables.c;h=ded5c48ad3c99829db7a8735a432a0a8cffd47f4;hb=f28909ad7b8374f226cbed5edf928484442131c3;hp=5cee7035f8fb17a8b21de494fc687a19329dde0a;hpb=f5c108becd49d78f4898cab11352291f5689d24e;p=pspp

diff --git a/src/language/dictionary/delete-variables.c b/src/language/dictionary/delete-variables.c
index 5cee7035f8..ded5c48ad3 100644
--- a/src/language/dictionary/delete-variables.c
+++ b/src/language/dictionary/delete-variables.c
@@ -1,32 +1,29 @@
-/* PSPP - computes sample statistics.
-   Copyright (C) 2006, 2007 Free Software Foundation, Inc.
-   Written by Ben Pfaff <blp@gnu.org>.
+/* PSPP - a program for statistical analysis.
+   Copyright (C) 2006, 2007, 2010, 2011, 2013 Free Software Foundation, Inc.
 
-   This program is free software; you can redistribute it and/or
-   modify it under the terms of the GNU General Public License as
-   published by the Free Software Foundation; either version 2 of the
-   License, or (at your option) any later version.
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
 
-   This program is distributed in the hope that it will be useful, but
-   WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   General Public License for more details.
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program; if not, write to the Free Software
-   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
-   02110-1301, USA. */
+   along with this program.  If not, see <http://www.gnu.org/licenses/>. */
 
 #include <config.h>
 
 #include <stdlib.h>
 
-#include <data/casereader.h>
-#include <data/dictionary.h>
-#include <data/procedure.h>
-#include <language/command.h>
-#include <language/lexer/variable-parser.h>
-#include <libpspp/message.h>
+#include "data/casereader.h"
+#include "data/dataset.h"
+#include "data/dictionary.h"
+#include "language/command.h"
+#include "language/lexer/variable-parser.h"
+#include "libpspp/message.h"
 
 #include "gettext.h"
 #define _(msgid) gettext (msgid)
@@ -40,25 +37,69 @@ cmd_delete_variables (struct lexer *lexer, struct dataset *ds)
   bool ok;
 
   if (proc_make_temporary_transformations_permanent (ds))
-    msg (SE, _("DELETE VARIABLES may not be used after TEMPORARY.  "
-               "Temporary transformations will be made permanent."));
+    msg (SE, _("%s may not be used after %s.  "
+               "Temporary transformations will be made permanent."),
+	 "DELETE VARIABLES", "TEMPORARY");
 
-  if (!parse_variables (lexer, dataset_dict (ds), &vars, &var_cnt,
-			      PV_NONE))
+  if (!parse_variables (lexer, dataset_dict (ds), &vars, &var_cnt, PV_NONE))
     goto error;
   if (var_cnt == dict_get_var_cnt (dataset_dict (ds)))
     {
-      msg (SE, _("DELETE VARIABLES may not be used to delete all variables "
-                 "from the active file dictionary.  Use NEW FILE instead."));
+      msg (SE, _("%s may not be used to delete all variables "
+                 "from the active dataset dictionary.  "
+                 "Use %s instead."), "DELETE VARIABLES", "NEW FILE");
       goto error;
     }
 
-  ok = casereader_destroy (proc_open (ds));
+  ok = casereader_destroy (proc_open_filtering (ds, false));
   ok = proc_commit (ds) && ok;
   if (!ok)
     goto error;
+
   dict_delete_vars (dataset_dict (ds), vars, var_cnt);
 
+  /* XXX A bunch of bugs conspire to make executing transformations again here
+     necessary, even though it shouldn't be.
+
+     Consider the following (which is included in delete-variables.at):
+
+        DATA LIST NOTABLE /s1 TO s2 1-2(A).
+        BEGIN DATA
+        12
+        END DATA.
+        DELETE VARIABLES s1.
+        NUMERIC n1.
+        LIST.
+
+     The DATA LIST gives us a caseproto with widths 1,1.  DELETE VARIABLES
+     deletes the first variable so we now have -1,1.  This already is
+     technically a problem because proc_casereader_read() calls
+     case_unshare_and_resize() from the former to the latter caseproto, and
+     these caseprotos are not conformable (which is a requirement for
+     case_resize()).  It doesn't cause an assert by default because
+     case_resize() uses expensive_assert() to check for it though.  However, in
+     practice we don't see a problem yet because case_resize() only does work
+     if the number of widths in the source and dest caseproto are different.
+
+     Executing NUMERIC adds a third variable, though, so we have -1,1,0.  This
+     makes caseproto_resize() notice that there are fewer strings in the new
+     caseproto.  Therefore it destroys the second one (s2).  It should destroy
+     the first one (s1), but if the caseprotos were really conformable then it
+     would have destroyed the right one.  This mistake eventually causes a bad
+     memory reference.
+
+     Executing transformations a second time after DELETE VARIABLES, like we do
+     below, works around the problem because we can never run into a situation
+     where we've got both new variables (triggering a resize) and deleted
+     variables (triggering the bad free).
+
+     We should fix this in a better way.  Doing it cleanly seems hard.  This
+     seems to work for now. */
+  ok = casereader_destroy (proc_open_filtering (ds, false));
+  ok = proc_commit (ds) && ok;
+  if (!ok)
+    goto error;
+
   free (vars);
 
   return CMD_SUCCESS;