fix style

Author: facontidavide

gtest/gtest_factory.cpp

@@ -100,7 +100,7 @@ TEST(BehaviorTreeFactory, VerifyLargeTree)
 
     BT::TreeNodePtr root_node = parser.instantiateTree(factory, nodes);
 
-    BT::PrintTreeRecursively(root_node.get());
+    BT::printTreeRecursively(root_node.get());
 
     ASSERT_EQ(root_node->name(), "root_selector");
 
@@ -155,7 +155,7 @@ TEST(BehaviorTreeFactory, Subtree)
     CrossDoor cross_door(factory);
 
     BT::TreeNodePtr root_node = parser.instantiateTree(factory, nodes);
-    BT::PrintTreeRecursively(root_node.get());
+    BT::printTreeRecursively(root_node.get());
 
     ASSERT_EQ(root_node->name(), "root_selector");
 

include/behavior_tree_core/behavior_tree.h

@@ -31,12 +31,12 @@
 
 namespace BT
 {
-void RecursiveVisitor(const TreeNode *node, const std::function<void(const TreeNode*)> visitor);
+void recursiveVisitor(const TreeNode *node, const std::function<void(const TreeNode*)> visitor);
 
 /**
  * Debug function to print on a stream
  */
-void PrintTreeRecursively(const TreeNode* root_node);
+void printTreeRecursively(const TreeNode* root_node);
 }
 
 #endif   // BEHAVIOR_TREE_H

include/behavior_tree_core/tree_node.h

@@ -32,6 +32,7 @@
 
 #include "behavior_tree_core/tick_engine.h"
 #include "behavior_tree_core/exceptions.h"
+#include "behavior_tree_core/signal.h"
 
 namespace BT
 {
@@ -154,23 +155,23 @@ typedef std::map<std::string, std::string> NodeParameters;
 class TreeNode
 {
   private:
-    // Node name
     std::string name_;
     NodeStatus status_;
+    Signal<NodeStatus,NodeStatus> state_change_signal_;
+    std::condition_variable state_condition_variable_;
+    mutable std::mutex state_mutex_;
 
   protected:
-    mutable std::mutex state_mutex_;
-    std::condition_variable state_condition_variable_;
 
     // Method to be implemented by the user
     virtual BT::NodeStatus tick() = 0;
 
   public:
-    // The constructor and the distructor
+    // The constructor and the destructor
     TreeNode(std::string name);
     virtual ~TreeNode() = default;
 
-    // The method that is going to be executed when the node receive a tick
+    // The method that should be executed to invoke the tick()
     virtual BT::NodeStatus executeTick();
 
     // The method used to interrupt the execution of the node
@@ -184,9 +185,24 @@ class TreeNode
     const std::string& name() const;
     void setName(const std::string& new_name);
 
+    // Will block until the status is either RUNNING, FAILURE or SUCCESS.
     BT::NodeStatus waitValidStatus();
 
     virtual NodeType type() const = 0;
+
+    using StateChangeCallback   = Signal<NodeStatus,NodeStatus>::CallableFuntion;
+    using StateChangeSubscriber = Signal<NodeStatus,NodeStatus>::Subscriber;
+
+    /**
+     * @brief subscribeToStateChange allows the user to have a callback invoked every time
+     * the state of the this TreeNode changes.
+     *
+     * @param callback funtion, must have the signature [ void callback(BT::NodeStatus prev_status, BT::NodeStatus new_status) ]
+     *
+     * @return the returned StateChangeSubscriber objects will be automatically unsubscribed when it goes out of scope.
+     */
+    StateChangeSubscriber subscribeToStateChange(StateChangeCallback callback);
+
 };
 
 typedef std::shared_ptr<TreeNode> TreeNodePtr;

src/behavior_tree.cpp

@@ -2,7 +2,7 @@
 
 namespace BT
 {
-void RecursiveVisitor(const TreeNode* node, const std::function<void(const TreeNode*)> visitor)
+void recursiveVisitor(const TreeNode* node, const std::function<void(const TreeNode*)> visitor)
 {
     if (!node)
     {
@@ -16,17 +16,17 @@ void RecursiveVisitor(const TreeNode* node, const std::function<void(const TreeN
     {
         for (const auto& child : control->children())
         {
-            RecursiveVisitor(child, visitor);
+            recursiveVisitor(child, visitor);
         }
     }
     auto decorator = dynamic_cast<const BT::DecoratorNode*>(node);
     if (decorator)
     {
-        RecursiveVisitor(decorator->child(), visitor);
+        recursiveVisitor(decorator->child(), visitor);
     }
 }
 
-void PrintTreeRecursively(const TreeNode* root_node)
+void printTreeRecursively(const TreeNode* root_node)
 {
     std::function<void(int, const BT::TreeNode*)> recursivePrint;