From ecbd585f12fd11e9efe689b6dce6a578fd0665cd Mon Sep 17 00:00:00 2001
From: Erik Boasson <eb@ilities.com>
Date: Wed, 25 Mar 2020 10:39:44 +0100
Subject: [PATCH] Generate header with compile-time features

Currently:

* DDS_HAS_SECURITY for DDS Security support
* DDS_HAS_LIFESPAN for lifespan QoS support
* DDS_HAS_DEADLINE_MISSED for "deadline missed" event support

These are defined to 1 if support for the feature is included in the
build and left undefined if it isn't.

Signed-off-by: Erik Boasson <eb@ilities.com>
---
 src/CMakeLists.txt              | 20 ++++++++++++++++++++
 src/core/ddsc/include/dds/dds.h |  1 +
 src/features.h.in               | 24 ++++++++++++++++++++++++
 3 files changed, 45 insertions(+)
 create mode 100644 src/features.h.in

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index ee0b287..9e5f5c7 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -16,6 +16,26 @@ if(NOT ${PROJECT_NAME} STREQUAL "CycloneDDS")
   message(FATAL_ERROR "Top-level CMakeLists.txt was moved to the top-level directory.  Please run cmake on ${dir} instead of ${CMAKE_CURRENT_LIST_DIR}")
 endif()
 
+# Generate a header file listing compile-time options relevant to the API.  Define to
+# "1" if enabled so that the generated features.h ends up having either
+#
+# - #define DDS_HAS_SECURITY 1
+# or
+# - /* #undef DDS_HAS_SECURITY */
+#
+# which caters both for those who prefer #ifdef DDS_HAS_SECURITY and for those who prefer
+# #if DDS_HAS_SECURITY.
+if(ENABLE_SECURITY)
+  set(DDS_HAS_SECURITY "1")
+endif()
+if(ENABLE_LIFESPAN)
+  set(DDS_HAS_LIFESPAN "1")
+endif()
+if(ENABLE_DEADLINE_MISSED)
+  set(DDS_HAS_DEADLINE_MISSED "1")
+endif()
+configure_file(features.h.in "${CMAKE_CURRENT_BINARY_DIR}/core/include/dds/features.h")
+
 add_definitions(-DDDSI_INCLUDE_NETWORK_PARTITIONS -DDDSI_INCLUDE_SSM)
 
 # OpenSSL is huge, raising the RSS by 1MB or so, and moreover find_package(OpenSSL) causes
diff --git a/src/core/ddsc/include/dds/dds.h b/src/core/ddsc/include/dds/dds.h
index b50f1d0..aa2f139 100644
--- a/src/core/ddsc/include/dds/dds.h
+++ b/src/core/ddsc/include/dds/dds.h
@@ -25,6 +25,7 @@
 #endif
 
 #include "dds/export.h"
+#include "dds/features.h"
 
 /**
  * Handle to an entity. A valid entity handle will always have a positive
diff --git a/src/features.h.in b/src/features.h.in
new file mode 100644
index 0000000..636f19f
--- /dev/null
+++ b/src/features.h.in
@@ -0,0 +1,24 @@
+/*
+ * Copyright(c) 2020 ADLINK Technology Limited and others
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Eclipse Distribution License
+ * v. 1.0 which is available at
+ * http://www.eclipse.org/org/documents/edl-v10.php.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause
+ */
+#ifndef _DDS_PUBLIC_FEATURES_H_
+#define _DDS_PUBLIC_FEATURES_H_
+
+/* Whether or not support for DDS Security is included */
+#cmakedefine DDS_HAS_SECURITY @DDS_HAS_SECURITY@
+
+/* Whether or not support for the lifespan QoS is included */
+#cmakedefine DDS_HAS_LIFESPAN @DDS_HAS_LIFESPAN@
+
+/* Whether or not support for generating "deadline missed" events is included */
+#cmakedefine DDS_HAS_DEADLINE_MISSED @DDS_HAS_DEADLINE_MISSED@
+
+#endif