1 files changed, 53 insertions, 1 deletions

diff --git a/src/lib/cc/command_interpreter.cc b/src/lib/cc/command_interpreter.cc
index c17230b242..163cdc1da0 100644
--- a/src/lib/cc/command_interpreter.cc
+++ b/src/lib/cc/command_interpreter.cc
@@ -8,8 +8,9 @@
 
 #include <exceptions/exceptions.h>
 #include <cc/command_interpreter.h>
-#include <string>
 #include <cc/data.h>
+#include <string>
+#include <set>
 
 using namespace std;
 
@@ -171,5 +172,56 @@ parseCommand(ConstElementPtr& arg, ConstElementPtr command) {
     return (cmd->stringValue());
 }
 
+ConstElementPtr
+combineCommandsLists(const ConstElementPtr& response1,
+                     const ConstElementPtr& response2) {
+    // Usually when this method is called there should be two non-null
+    // responses. If there is just a single response, return this
+    // response.
+    if (!response1 && response2) {
+        return (response2);
+
+    } else if (response1 && !response2) {
+        return (response1);
+
+    } else if (!response1 && !response2) {
+        return (ConstElementPtr());
+
+    } else {
+        // Both responses are non-null so we need to combine the lists
+        // of supported commands if the status codes are 0.
+        int status_code;
+        ConstElementPtr args1 = parseAnswer(status_code, response1);
+        if (status_code != 0) {
+            return (response1);
+        }
+
+        ConstElementPtr args2 = parseAnswer(status_code, response2);
+        if (status_code != 0) {
+            return (response2);
+        }
+
+        const std::vector<ElementPtr> vec1 = args1->listValue();
+        const std::vector<ElementPtr> vec2 = args2->listValue();
+
+        // Storing command names in a set guarantees that the non-unique
+        // command names are aggregated.
+        std::set<std::string> combined_set;
+        for (auto v = vec1.cbegin(); v != vec1.cend(); ++v) {
+            combined_set.insert((*v)->stringValue());
+        }
+        for (auto v = vec2.cbegin(); v != vec2.cend(); ++v) {
+            combined_set.insert((*v)->stringValue());
+        }
+
+        // Create a combined list of commands.
+        ElementPtr combined_list = Element::createList();
+        for (auto s = combined_set.cbegin(); s != combined_set.cend(); ++s) {
+            combined_list->add(Element::create(*s));
+        }
+        return (createAnswer(CONTROL_RESULT_SUCCESS, combined_list));
+    }
+}
+
 }
 }