Add rcl_node_get_fully_qualified_name (#255)

rcl/include/rcl/node.h

@@ -352,6 +352,29 @@ RCL_WARN_UNUSED
 const char *
 rcl_node_get_namespace(const rcl_node_t * node);
 
+/// Return the fully qualified name of the node.
+/**
+ * This function returns the node's internal namespace and name combined string.
+ * This function can fail, and therefore return `NULL`, if:
+ *   - node is `NULL`
+ *   - node has not been initialized (the implementation is invalid)
+ *
+ * <hr>
+ * Attribute          | Adherence
+ * ------------------ | -------------
+ * Allocates Memory   | Yes
+ * Thread-Safe        | No
+ * Uses Atomics       | No
+ * Lock-Free          | Yes
+ *
+ * \param[in] node pointer to the node
+ * \return fully qualified name string if successful, otherwise `NULL`
+ */
+RCL_PUBLIC
+RCL_WARN_UNUSED
+const char *
+rcl_node_get_fully_qualified_name(const rcl_node_t * node);
+
 /// Return the rcl node options.
 /**
  * This function returns the node's internal options struct.

rcl/src/rcl/node.c

@@ -603,6 +603,31 @@ rcl_node_get_namespace(const rcl_node_t * node)
   return node->impl->rmw_node_handle->namespace_;
 }
 
+const char *
+rcl_node_get_fully_qualified_name(const rcl_node_t * node)
+{
+  if (!rcl_node_is_valid_except_context(node)) {
+    return NULL;  // error already set
+  }
+
+  const char * name = rcl_node_get_name(node);
+  const char * ns = rcl_node_get_namespace(node);
+  char * fq_name = NULL;
+
+  if ('/' == ns[strlen(ns) - 1]) {
+    fq_name = (char *)calloc(strlen(ns) + strlen(name), sizeof(char));
+    strcpy(fq_name, ns);
+    strcat(fq_name, name);
+  }
+  else {
+    fq_name = (char *)calloc(strlen(ns) + strlen(name) + 1, sizeof(char));
+    strcpy(fq_name, ns);
+    strcat(fq_name, "/");
+    strcat(fq_name, name);
+  }
+  return fq_name;
+}
+
 const rcl_node_options_t *
 rcl_node_get_options(const rcl_node_t * node)
 {

rcl/test/rcl/test_node.cpp

@@ -16,6 +16,7 @@
 
 #include <regex>
 #include <string>
+#include <cstdlib>
 
 #include "rcl/rcl.h"
 #include "rcl/node.h"
@@ -99,6 +100,7 @@ TEST_F(CLASSNAME(TestNodeFixture, RMW_IMPLEMENTATION), test_rcl_node_accessors)
   rcl_node_t invalid_node = rcl_get_zero_initialized_node();
   const char * name = "test_rcl_node_accessors_node";
   const char * namespace_ = "/ns";
+  const char * fq_name = "/ns/test_rcl_node_accessors_node";
   rcl_node_options_t default_options = rcl_node_get_default_options();
   default_options.domain_id = 42;  // Set the domain id to something explicit.
   ret = rcl_node_init(&invalid_node, name, namespace_, &invalid_context, &default_options);
@@ -204,6 +206,27 @@ TEST_F(CLASSNAME(TestNodeFixture, RMW_IMPLEMENTATION), test_rcl_node_accessors)
   if (actual_node_namespace) {
     EXPECT_EQ(std::string(namespace_), std::string(actual_node_namespace));
   }
+  // Test rcl_node_get_fully_qualified_name().
+  const char * actual_fq_node_name;
+  actual_fq_node_name = rcl_node_get_fully_qualified_name(nullptr);
+  EXPECT_EQ(nullptr, actual_fq_node_name);
+  rcl_reset_error();
+  actual_fq_node_name = rcl_node_get_fully_qualified_name(&zero_node);
+  EXPECT_EQ(nullptr, actual_fq_node_name);
+  rcl_reset_error();
+  actual_fq_node_name = rcl_node_get_fully_qualified_name(&invalid_node);
+  EXPECT_TRUE(actual_fq_node_name ? true : false);
+  if (actual_fq_node_name) {
+    EXPECT_STREQ(fq_name, actual_fq_node_name);
+    free((char *)actual_fq_node_name);
+  }
+  rcl_reset_error();
+  actual_fq_node_name = rcl_node_get_fully_qualified_name(&node);
+  EXPECT_TRUE(actual_fq_node_name ? true : false);
+  if (actual_fq_node_name) {
+    EXPECT_EQ(std::string(fq_name), std::string(actual_fq_node_name));
+    free((char *)actual_fq_node_name);
+  }
   // Test rcl_node_get_logger_name().
   const char * actual_node_logger_name;
   actual_node_logger_name = rcl_node_get_logger_name(nullptr);