Libguestfs - Feb 2017 - [PATCH nbdkit v2] Really fix C++ support in the <nbdkit-plugin.h>

This version uses Eric's subtype suggestion:
https://bugzilla.redhat.com/show_bug.cgi?id=1418328#c6

Rich.

Fixes commit 3647fe831a5c6d12832c4e48d1337489fd44fa59.
---
 .gitignore                |   1 -
 include/nbdkit-plugin.h   |  15 +++--
 tests/Makefile.am         |  39 ++++++++----
 tests/test-cxx-plugin.cpp | 152 ++++++++++++++++++++++++++++++++++++++++++++++
 tests/test-cxx.cpp        |  44 --------------
 tests/test-cxx.sh         |  38 ++++++++++++
 6 files changed, 227 insertions(+), 62 deletions(-)
 create mode 100644 tests/test-cxx-plugin.cpp
 delete mode 100644 tests/test-cxx.cpp
 create mode 100755 tests/test-cxx.sh

diff --git a/.gitignore b/.gitignore
index 0f4e574..59e9510 100644
--- a/.gitignore
+++ b/.gitignore
@@ -43,7 +43,6 @@ Makefile.in
 /tests/disk.xz
 /tests/file-data
 /tests/test-connect
-/tests/test-cxx
 /tests/test-file
 /tests/test-gzip
 /tests/test-newstyle
diff --git a/include/nbdkit-plugin.h b/include/nbdkit-plugin.h
index 9b3a5c9..568aaf5 100644
--- a/include/nbdkit-plugin.h
+++ b/include/nbdkit-plugin.h
@@ -36,13 +36,13 @@
 #ifndef NBDKIT_PLUGIN_H
 #define NBDKIT_PLUGIN_H
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 #include <stdarg.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define NBDKIT_THREAD_MODEL_SERIALIZE_CONNECTIONS     0
 #define NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS    1
 #define NBDKIT_THREAD_MODEL_SERIALIZE_REQUESTS        2
@@ -108,7 +108,14 @@ extern void nbdkit_vdebug (const char *msg, va_list args);
 extern char *nbdkit_absolute_path (const char *path);
 extern int64_t nbdkit_parse_size (const char *str);
 
+#ifdef __cplusplus
+#define NBDKIT_CXX_LANG_C extern "C"
+#else
+#define NBDKIT_CXX_LANG_C /* nothing */
+#endif
+
 #define NBDKIT_REGISTER_PLUGIN(plugin)                                  \
+  NBDKIT_CXX_LANG_C                                                     \
   struct nbdkit_plugin *                                                \
   plugin_init (void)                                                    \
   {                                                                     \
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c2d473a..daf1d2a 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -71,6 +71,12 @@ check-valgrind:
 
 # Basic server command line and start-up tests.
 
+check_PROGRAMS +check_DATA +check_SCRIPTS +check_LTLIBRARIES
+noinst_LTLIBRARIES +
 TESTS = \
 	test-help.sh \
 	test-help-plugin.sh \
@@ -86,24 +92,34 @@ TESTS = \
 	test-ipv4.sh \
 	test-socket-activation
 
-check_PROGRAMS = \
+check_PROGRAMS += \
 	test-socket-activation
 
 test_socket_activation_SOURCES = test-socket-activation.c
 test_socket_activation_CFLAGS = $(WARNINGS_CFLAGS)
 
 if HAVE_CXX
-# Test we can include the <nbdkit-plugin.h> header file from C++.
-# The test does nothing interesting, we're only interested if
-# it builds.
+# This builds a plugin using the C++ compiler.  The plugin
+# doesn't do anything interesting when run.
 TESTS += \
-	test-cxx
-check_PROGRAMS += \
-	test-cxx
+	test-cxx.sh
+# check_LTLIBRARIES won't build a shared library (see automake manual).
+# So we have to do this and add a dependency.
+noinst_LTLIBRARIES += \
+	test-cxx-plugin.la
+test-cxx.sh: test-cxx-plugin.la
 
-test_cxx_SOURCES = test-cxx.cpp
-test_cxx_CXXFLAGS = \
+test_cxx_plugin_la_SOURCES = \
+	test-cxx-plugin.cpp \
+	$(top_srcdir)/include/nbdkit-plugin.h
+test_cxx_plugin_la_CPPFLAGS = \
+	-I$(top_srcdir)/include
+test_cxx_plugin_la_CXXFLAGS = \
         $(WARNINGS_CFLAGS)
+# For use of the -rpath option, see:
+# https://lists.gnu.org/archive/html/libtool/2007-07/msg00067.html
+test_cxx_plugin_la_LDFLAGS = \
+	-module -avoid-version -shared -rpath /nowhere
 endif
 
 # In-depth tests need libguestfs, since that is a convenient way to
@@ -120,13 +136,10 @@ TESTS_ENVIRONMENT = \
 	LD_LIBRARY_PATH=../plugins/ocaml/.libs
 
 # Common test library.
-check_LTLIBRARIES = libtest.la
+check_LTLIBRARIES += libtest.la
 libtest_la_SOURCES = test.c test.h
 libtest_la_CFLAGS = $(WARNINGS_CFLAGS)
 
-check_DATA -check_SCRIPTS -
 # Basic connection test.
 check_PROGRAMS += test-connect
 TESTS += test-connect.sh
diff --git a/tests/test-cxx-plugin.cpp b/tests/test-cxx-plugin.cpp
new file mode 100644
index 0000000..1568497
--- /dev/null
+++ b/tests/test-cxx-plugin.cpp
@@ -0,0 +1,152 @@
+/* nbdkit
+ * Copyright (C) 2013-2017 Red Hat Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of Red Hat nor the names of its contributors may be
+ * used to endorse or promote products derived from this software without
+ * specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS
IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+ * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+ * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef __cplusplus
+#error "this test should be compiled with a C++ compiler"
+#endif
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <nbdkit-plugin.h>
+
+/* This looks like a 100MB disk with one empty partition. */
+static unsigned char bootsector[512] = {
+  0xfa, 0xb8, 0x00, 0x10, 0x8e, 0xd0, 0xbc, 0x00,
+  0xb0, 0xb8, 0x00, 0x00, 0x8e, 0xd8, 0x8e, 0xc0,
+  0xfb, 0xbe, 0x00, 0x7c, 0xbf, 0x00, 0x06, 0xb9,
+  0x00, 0x02, 0xf3, 0xa4, 0xea, 0x21, 0x06, 0x00,
+  0x00, 0xbe, 0xbe, 0x07, 0x38, 0x04, 0x75, 0x0b,
+  0x83, 0xc6, 0x10, 0x81, 0xfe, 0xfe, 0x07, 0x75,
+  0xf3, 0xeb, 0x16, 0xb4, 0x02, 0xb0, 0x01, 0xbb,
+  0x00, 0x7c, 0xb2, 0x80, 0x8a, 0x74, 0x01, 0x8b,
+  0x4c, 0x02, 0xcd, 0x13, 0xea, 0x00, 0x7c, 0x00,
+  0x00, 0xeb, 0xfe, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0xe1, 0x5b, 0x02, 0x00, 0x00, 0x00, 0x00, 0x02,
+  0x03, 0x00, 0x83, 0xbc, 0x31, 0x0c, 0x80, 0x00,
+  0x00, 0x00, 0x01, 0x1f, 0x03, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0xaa
+};
+static unsigned char data[104857600];
+
+static void
+cxx_load (void)
+{
+  memcpy (data, bootsector, sizeof bootsector);
+}
+
+static void *
+cxx_open (int readonly)
+{
+  return data;
+}
+
+static int64_t
+cxx_get_size (void *handle)
+{
+  return (int64_t) sizeof (data);
+}
+
+#define THREAD_MODEL NBDKIT_THREAD_MODEL_SERIALIZE_ALL_REQUESTS
+
+static int
+cxx_pread (void *handle, void *buf, uint32_t count, uint64_t offset)
+{
+  memcpy (buf, data+offset, count);
+  return 0;
+}
+
+/* https://bugzilla.redhat.com/show_bug.cgi?id=1418328#c6 */
+static struct nbdkit_plugin_temp : nbdkit_plugin { nbdkit_plugin_temp() {
+  name = "cxx";
+  version = PACKAGE_VERSION;
+  load = cxx_load;
+  open = cxx_open;
+  get_size = cxx_get_size;
+  pread = cxx_pread;
+} } plugin;
+
+NBDKIT_REGISTER_PLUGIN(plugin)
diff --git a/tests/test-cxx.cpp b/tests/test-cxx.cpp
deleted file mode 100644
index a78c4a3..0000000
--- a/tests/test-cxx.cpp
+++ /dev/null
@@ -1,44 +0,0 @@
-/* nbdkit
- * Copyright (C) 2017 Red Hat Inc.
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met:
- *
- * * Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * * Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * * Neither the name of Red Hat nor the names of its contributors may be
- * used to endorse or promote products derived from this software without
- * specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS
IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
- * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
- * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
- * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-
-#ifndef __cplusplus
-#error "this test should be compiled with a C++ compiler"
-#endif
-
-#include "nbdkit-plugin.h"
-
-int
-main (int argc, char *argv[])
-{
-  return 0;
-}
diff --git a/tests/test-cxx.sh b/tests/test-cxx.sh
new file mode 100755
index 0000000..1b86167
--- /dev/null
+++ b/tests/test-cxx.sh
@@ -0,0 +1,38 @@
+#!/bin/bash -
+# nbdkit
+# Copyright (C) 2017 Red Hat Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+# * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+# notice, this list of conditions and the following disclaimer in the
+# documentation and/or other materials provided with the distribution.
+#
+# * Neither the name of Red Hat nor the names of its contributors may be
+# used to endorse or promote products derived from this software without
+# specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY RED HAT AND CONTRIBUTORS ''AS
IS'' AND
+# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
+# THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+# PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL RED HAT OR
+# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+# SUCH DAMAGE.
+
+set -e
+
+# We only really care that the plugin compiled, so we don't
+# need to run it properly.
+$VG ../src/nbdkit ./.libs/test-cxx-plugin.so --version
-- 
2.10.2