Add wmem scopes for packet and file lifetimes. The file lifetime scope isn't

yet initialized because I can't figure out where the enter() and leave() calls
should go - the obvious place in packet.c causes a lot of assertion errors.

svn path=/trunk/; revision=45879

1 files changed, 176 insertions, 0 deletions

diff --git a/epan/wmem/wmem_scopes.c b/epan/wmem/wmem_scopes.c
new file mode 100644
index 0000000000..8d0e1a2268
--- /dev/null
+++ b/epan/wmem/wmem_scopes.c
@@ -0,0 +1,176 @@
+/* wmem_scopes.c
+ * Wireshark Memory Manager Scopes
+ * Copyright 2012, Evan Huus <eapache@gmail.com>
+ *
+ * $Id$
+ *
+ * Wireshark - Network traffic analyzer
+ * By Gerald Combs <gerald@wireshark.org>
+ * Copyright 1998 Gerald Combs
+ *
+ * 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 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.
+ */
+
+#include <glib.h>
+
+#include "wmem_scopes.h"
+#include "wmem_allocator_glib.h"
+
+/* One of the supposed benefits of wmem over the old emem was going to be that
+ * the scoping of the various memory pools would be obvious, since they would
+ * no longer be global. Instead, the pools would be managed as variables scoped
+ * by the compiler, so functions outside of that scope wouldn't have access to
+ * the pools and wouldn't be able to allocate memory in a scope to which they
+ * didn't belong.
+ *
+ * That idea fell apart rather quickly :P
+ *
+ * The principle still stands, and most pools should be managed in that way.
+ * The three in this file are *exceptions*. They are the three scopes that emem
+ * provided as globals. Converting all of the code that used them to pass an
+ * extra parameter (or three) around would have been a nightmare of epic
+ * proportions, so we provide these three as globals still.
+ *
+ * We do, however, use some extra booleans and a mountain of assertions to try
+ * and catch anybody accessing the pools out of the correct scope. It's not
+ * perfect, but it should stop most of the bad behaviour that emem permitted.
+ */
+
+/* TODO: Make these thread-local */
+static wmem_allocator_t *epan_scope   = NULL;
+static wmem_allocator_t *packet_scope = NULL;
+static wmem_allocator_t *file_scope   = NULL;
+
+static gboolean in_packet_scope = FALSE;
+static gboolean in_file_scope   = FALSE;
+
+/* Epan Scope */
+
+wmem_allocator_t *
+wmem_epan_scope(void)
+{
+    g_assert(epan_scope);
+
+    return epan_scope;
+}
+
+/* Packet Scope */
+
+wmem_allocator_t *
+wmem_packet_scope(void)
+{
+    g_assert(packet_scope);
+    g_assert(in_packet_scope);
+
+    return epan_scope;
+}
+
+void
+wmem_enter_packet_scope(void)
+{
+    g_assert(packet_scope);
+    g_assert(!in_packet_scope);
+
+    in_packet_scope = TRUE;
+}
+
+void
+wmem_leave_packet_scope(void)
+{
+    g_assert(packet_scope);
+    g_assert(in_packet_scope);
+
+    wmem_free_all(packet_scope);
+    in_packet_scope = FALSE;
+}
+
+/* File Scope */
+
+wmem_allocator_t *
+wmem_file_scope(void)
+{
+    g_assert(file_scope);
+    g_assert(in_file_scope);
+
+    return epan_scope;
+}
+
+void
+wmem_enter_file_scope(void)
+{
+    g_assert(file_scope);
+    g_assert(!in_file_scope);
+
+    in_file_scope = TRUE;
+}
+
+void
+wmem_leave_file_scope(void)
+{
+    g_assert(file_scope);
+    g_assert(in_file_scope);
+
+    wmem_free_all(file_scope);
+    in_file_scope = FALSE;
+}
+
+/* Scope Management */
+
+void
+wmem_init_scopes(void)
+{
+    g_assert(epan_scope   == NULL);
+    g_assert(packet_scope == NULL);
+    g_assert(file_scope   == NULL);
+
+    g_assert(in_packet_scope == FALSE);
+    g_assert(in_file_scope   == FALSE);
+
+    epan_scope   = wmem_create_glib_allocator();
+    packet_scope = wmem_create_glib_allocator();
+    file_scope   = wmem_create_glib_allocator();
+}
+
+void
+wmem_cleanup_scopes(void)
+{
+    g_assert(epan_scope);
+    g_assert(packet_scope);
+    g_assert(file_scope);
+
+    g_assert(in_packet_scope == FALSE);
+    g_assert(in_file_scope   == FALSE);
+
+    wmem_destroy_allocator(epan_scope);
+    wmem_destroy_allocator(packet_scope);
+    wmem_destroy_allocator(file_scope);
+
+    epan_scope   = NULL;
+    packet_scope = NULL;
+    file_scope   = NULL;
+}
+
+/*
+ * Editor modelines  -  http://www.wireshark.org/tools/modelines.html
+ *
+ * Local variables:
+ * c-basic-offset: 4
+ * tab-width: 8
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * vi: set shiftwidth=4 tabstop=8 expandtab:
+ * :indentSize=4:tabSize=8:noTabs=true:
+ */