llist: Add a C++ wrapper for linux_list

This commit adds the LListHead class which is a wrapper around the
linuxlist. It adds an additional member to refer to the container,
since the container_of macro doesn't work properly with C++ classes.
All functions and macros from linuxlist.h are support except for the
entry macros (e.g. llist_entry, llist_for_each_entry, ...). To access
the container (entry), an entry() method is provided instead:

  llist_for_each(pos, &elems) {
      pos->entry()->do_something();
  }

Sponsored-by: On-Waves ehf

.gitignore

@@ -37,6 +37,7 @@ tests/rlcmac/RLCMACTest
 tests/tbf/TbfTest
 tests/types/TypesTest
 tests/ms/MsTest
+tests/llist/LListTest
 tests/emu/pcu_emu
 tests/testsuite
 tests/testsuite.log

src/Makefile.am

@@ -95,7 +95,8 @@ noinst_HEADERS = \
 	rlc.h \
 	decoding.h \
 	llc.h \
-	pcu_utils.h
+	pcu_utils.h \
+	cxx_linuxlist.h
 
 osmo_pcu_SOURCES = pcu_main.cpp
 

src/cxx_linuxlist.h

@@ -0,0 +1,133 @@
+/* cxx_linuxlist.h
+ *
+ * Copyright (C) 2015 by Sysmocom s.f.m.c. GmbH
+ * Author: Jacob Erlbeck <jerlbeck@sysmocom.de>
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#pragma once
+
+extern "C" {
+	#include <osmocom/core/linuxlist.h>
+}
+
+template <typename T>
+struct LListHead {
+	typedef T entry_t;
+
+	/* This must match the declaration of struct llist_head */
+	LListHead<T> *next;
+	LListHead<T> *prev;
+
+	LListHead() : m_back(0) { INIT_LLIST_HEAD(this); }
+	LListHead(T* entry) : m_back(entry) {
+		next = (LListHead<T> *)LLIST_POISON1;
+		prev = (LListHead<T> *)LLIST_POISON2;
+	}
+
+	T *entry() {return m_back;}
+	const T *entry() const {return m_back;}
+
+	llist_head &llist() {
+		return *static_cast<llist_head *>(static_cast<void *>(this));
+	}
+	const llist_head &llist() const {
+		return *static_cast<llist_head *>(static_cast<void *>(this));
+	}
+
+private:
+	T *const m_back;
+};
+
+/* Define a family of casting functions */
+template <typename T>
+llist_head &llist(LListHead<T> &l)
+{
+	return l->llist();
+}
+
+template <typename T>
+const llist_head &llist(const LListHead<T> &l)
+{
+	return l->llist();
+}
+
+template <typename T>
+llist_head *llptr(LListHead<T> *l)
+{
+	return &(l->llist());
+}
+
+template <typename T>
+const llist_head *llptr(const LListHead<T> *l)
+{
+	return &(l->llist());
+}
+
+/* Define type-safe wrapper for the existing linux_list.h functions */
+template <typename T>
+inline void llist_add(LListHead<T> *new_, LListHead<T> *head)
+{
+	llist_add(llptr(new_), llptr(head));
+}
+
+template <typename T>
+inline void llist_add_tail(LListHead<T> *new_, LListHead<T> *head)
+{
+	llist_add_tail(llptr(new_), llptr(head));
+}
+
+template <typename T>
+inline void llist_del(LListHead<T> *entry)
+{
+	llist_del(llptr(entry));
+}
+
+template <typename T>
+inline void llist_del_init(LListHead<T> *entry)
+{
+	llist_del_init(llptr(entry));
+}
+
+template <typename T>
+inline void llist_move(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_move(llptr(list), llptr(head));
+}
+
+template <typename T>
+inline void llist_move_tail(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_move_tail(llptr(list), llptr(head));
+}
+
+template <typename T>
+inline int llist_empty(const LListHead<T> *head)
+{
+	return llist_empty(llptr(head));
+}
+
+template <typename T>
+inline void llist_splice(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_splice(llptr(list), llptr(head));
+}
+
+template <typename T>
+inline void llist_splice_init(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_splice_init(llptr(list), llptr(head));
+}

tests/Makefile.am

@@ -1,6 +1,6 @@
 AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES) $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGB_CFLAGS) $(LIBOSMOGSM_CFLAGS) -I$(top_srcdir)/src/
 
-check_PROGRAMS = rlcmac/RLCMACTest alloc/AllocTest tbf/TbfTest types/TypesTest ms/MsTest
+check_PROGRAMS = rlcmac/RLCMACTest alloc/AllocTest tbf/TbfTest types/TypesTest ms/MsTest llist/LListTest
 noinst_PROGRAMS = emu/pcu_emu
 
 rlcmac_RLCMACTest_SOURCES = rlcmac/RLCMACTest.cpp
@@ -54,6 +54,14 @@ ms_MsTest_LDADD = \
 ms_MsTest_LDFLAGS = \
 	-Wl,-u,bssgp_prim_cb
 
+llist_LListTest_SOURCES = llist/LListTest.cpp
+llist_LListTest_LDADD = \
+	$(top_builddir)/src/libgprs.la \
+	$(LIBOSMOGB_LIBS) \
+	$(LIBOSMOGSM_LIBS) \
+	$(LIBOSMOCORE_LIBS) \
+	$(COMMON_LA)
+
 # The `:;' works around a Bash 3.2 bug when the output is not writeable.
 $(srcdir)/package.m4: $(top_srcdir)/configure.ac
 	:;{ \
@@ -78,7 +86,8 @@ EXTRA_DIST = \
 	alloc/AllocTest.ok alloc/AllocTest.err \
 	tbf/TbfTest.ok tbf/TbfTest.err \
 	types/TypesTest.ok types/TypesTest.err \
-	ms/MsTest.ok ms/MsTest.err
+	ms/MsTest.ok ms/MsTest.err \
+	llist/LListTest.ok llist/LListTest.err
 
 DISTCLEANFILES = atconfig
 

tests/llist/LListTest.cpp

@@ -0,0 +1,87 @@
+/*
+ * LListTest.cpp
+ *
+ * Copyright (C) 2015 by Sysmocom s.f.m.c. GmbH
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Affero 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.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "cxx_linuxlist.h"
+
+extern "C" {
+#include <osmocom/core/application.h>
+#include <osmocom/core/talloc.h>
+#include <osmocom/core/utils.h>
+}
+
+#include <errno.h>
+
+
+struct TestElem {
+	const char *str;
+	LListHead<TestElem> list;
+
+	TestElem(const char *s) : str(s), list(this) {};
+};
+
+static void test_linux_list()
+{
+	LListHead<TestElem> elems, *pos, *tmp;
+	TestElem elem1("number one");
+	TestElem elem2("number two");
+	TestElem elem3("number three");
+	int count = 0;
+
+	printf("=== start %s ===\n", __func__);
+
+	llist_add_tail(&elem1.list, &elems);
+	llist_add_tail(&elem2.list, &elems);
+	llist_add_tail(&elem3.list, &elems);
+
+	llist_for_each(pos, &elems) {
+		count += 1;
+		printf(" %i -> %s\n", count, pos->entry()->str);
+	}
+	OSMO_ASSERT(count == 3);
+
+	count = 0;
+	llist_for_each_safe(pos, tmp, &elems) {
+		count += 1;
+		if (count == 2)
+			llist_del(pos);
+
+		printf(" %i -> %s\n", count, pos->entry()->str);
+	}
+	OSMO_ASSERT(count == 3);
+
+	count = 0;
+	llist_for_each(pos, &elems) {
+		count += 1;
+		OSMO_ASSERT(pos != &elem2.list);
+		printf(" %i -> %s\n", count, pos->entry()->str);
+	}
+	OSMO_ASSERT(count == 2);
+
+	printf("=== end %s ===\n", __func__);
+}
+
+int main(int argc, char **argv)
+{
+	test_linux_list();
+
+	return EXIT_SUCCESS;
+}

tests/llist/LListTest.ok

@@ -0,0 +1,10 @@
+=== start test_linux_list ===
+ 1 -> number one
+ 2 -> number two
+ 3 -> number three
+ 1 -> number one
+ 2 -> number two
+ 3 -> number three
+ 1 -> number one
+ 2 -> number three
+=== end test_linux_list ===

tests/ms/MsTest.cpp

@@ -231,7 +231,6 @@ static void test_ms_replace_tbf()
 	printf("=== end %s ===\n", __func__);
 }
 
-
 static const struct log_info_cat default_categories[] = {
 	{"DPCU", "", "GPRS Packet Control Unit (PCU)", LOGL_INFO, 1},
 };

tests/testsuite.at

@@ -36,3 +36,10 @@ cat $abs_srcdir/ms/MsTest.ok > expout
 cat $abs_srcdir/ms/MsTest.err > experr
 AT_CHECK([$OSMO_QEMU $abs_top_builddir/tests/ms/MsTest], [0], [expout], [experr])
 AT_CLEANUP
+
+AT_SETUP([llist])
+AT_KEYWORDS([llist])
+cat $abs_srcdir/llist/LListTest.ok > expout
+cat $abs_srcdir/llist/LListTest.err > experr
+AT_CHECK([$OSMO_QEMU $abs_top_builddir/tests/llist/LListTest], [0], [expout], [experr])
+AT_CLEANUP