check rmw id using RCL_ASSERT_RMW_ID_MATCHES (#51)

* check rmw id using RCL_CHECK_RMW_ID_MATCHES_OR_DIE

* return a more distinct return code on mismatch

* rename env var to RCL_ASSERT_RMW_ID_MATCHES

* [style] fixup

rcl/CMakeLists.txt

@@ -24,11 +24,12 @@ set(${PROJECT_NAME}_sources
   src/rcl/node.c
   src/rcl/publisher.c
   src/rcl/rcl.c
+  src/rcl/rmw_implementation_identifier_check.c
   src/rcl/service.c
   src/rcl/subscription.c
-  src/rcl/wait.c
   src/rcl/time.c
   src/rcl/timer.c
+  src/rcl/wait.c
 )
 
 macro(target)

rcl/include/rcl/types.h

@@ -26,6 +26,7 @@ typedef rmw_ret_t rcl_ret_t;
 #define RCL_RET_NOT_INIT 101
 #define RCL_RET_BAD_ALLOC 102
 #define RCL_RET_INVALID_ARGUMENT 103
+#define RCL_RET_MISMATCHED_RMW_ID 104
 // rcl node specific ret codes in 2XX
 #define RCL_RET_NODE_INVALID 200
 // rcl publisher specific ret codes in 3XX

rcl/src/rcl/rmw_implementation_identifier_check.c

@@ -0,0 +1,77 @@
+// Copyright 2016 Open Source Robotics Foundation, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#if __cplusplus
+extern "C"
+{
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <rmw/rmw.h>
+
+#include "rcl/types.h"
+#include "./common.h"
+
+// Extracted this portable method of doing a "shared library constructor" from SO:
+//   http://stackoverflow.com/a/2390626/671658
+// Initializer/finalizer sample for MSVC and GCC/Clang.
+// 2010-2016 Joe Lowe. Released into the public domain.
+#if defined(_MSC_VER)
+  #pragma section(".CRT$XCU", read)
+  #define INITIALIZER2_(f, p) \
+  static void f(void); \
+  __declspec(allocate(".CRT$XCU")) void(*f ## _)(void) = f; \
+  __pragma(comment(linker, "/include:" p #f "_")) \
+  static void f(void)
+  #ifdef _WIN64
+    #define INITIALIZER(f) INITIALIZER2_(f, "")
+  #else
+    #define INITIALIZER(f) INITIALIZER2_(f, "_")
+  #endif
+#else
+  #define INITIALIZER(f) \
+  static void f(void) __attribute__((constructor)); \
+  static void f(void)
+#endif
+
+INITIALIZER(initialize) {
+  // If the environement variable RCL_ASSERT_RMW_ID_MATCHES is set,
+  // check that the result of `rmw_get_implementation_identifier` matches.
+  const char * expected = NULL;
+  rcl_ret_t ret = rcl_impl_getenv("RCL_ASSERT_RMW_ID_MATCHES", &expected);
+  if (ret != RCL_RET_OK) {
+    fprintf(stderr,
+      "Error getting environement variable 'RCL_ASSERT_RMW_ID_MATCHES': %s\n",
+      rcl_get_error_string_safe()
+    );
+    exit(ret);
+  }
+  // If the environment variable is set, and it does not match, print a warning and exit.
+  if (strlen(expected) > 0 && strcmp(rmw_get_implementation_identifier(), expected) != 0) {
+    fprintf(stderr,
+      "Expected RMW implementation identifier of '%s' but instead found '%s', exiting with %d.\n",
+      expected,
+      rmw_get_implementation_identifier(),
+      RCL_RET_MISMATCHED_RMW_ID
+    );
+    exit(RCL_RET_MISMATCHED_RMW_ID);
+  }
+}
+
+#if __cplusplus
+}
+#endif