Added Root mutable accessors, and Root::Clone function

include/sdf/Root.hh

@@ -125,6 +125,13 @@ namespace sdf
     /// \sa uint64_t WorldCount() const
     public: const World *WorldByIndex(const uint64_t _index) const;
 
+    /// \brief Get a mutable world based on an index.
+    /// \param[in] _index Index of the world. The index should be in the
+    /// range [0..WorldCount()).
+    /// \return Pointer to the world. Nullptr if the index does not exist.
+    /// \sa uint64_t WorldCount() const
+    public: World *WorldByIndex(const uint64_t _index);
+
     /// \brief Get whether a world name exists.
     /// \param[in] _name Name of the world to check.
     /// \return True if there exists a world with the given name.
@@ -151,6 +158,16 @@ namespace sdf
     /// not been called.
     public: sdf::ElementPtr Element() const;
 
+    /// \brief Add a world to the root.
+    /// \param[in] _word World to add.
+    /// \return True if successful, false if a world with the name already
+    /// exists.
+    /// \return True on success, false if the world name already exists.
+    public: bool AddWorld(const World &_world);
+
+    /// \brief Remove all worlds.
+    public: void ClearWorlds();
+
     /// \brief Private data pointer
     IGN_UTILS_UNIQUE_IMPL_PTR(dataPtr)
   };

src/Root.cc

@@ -381,6 +381,14 @@ const World *Root::WorldByIndex(const uint64_t _index) const
   return nullptr;
 }
 
+/////////////////////////////////////////////////
+World *Root::WorldByIndex(const uint64_t _index)
+{
+  if (_index < this->dataPtr->worlds.size())
+    return &this->dataPtr->worlds[_index];
+  return nullptr;
+}
+
 /////////////////////////////////////////////////
 bool Root::WorldNameExists(const std::string &_name) const
 {
@@ -417,3 +425,20 @@ sdf::ElementPtr Root::Element() const
 {
   return this->dataPtr->sdf;
 }
+
+/////////////////////////////////////////////////
+bool Root::AddWorld(const World &_world)
+{
+  if (!this->WorldNameExists(_world.Name()))
+  {
+    this->dataPtr->worlds.push_back(_world);
+    return true;
+  }
+  return false;
+}
+
+/////////////////////////////////////////////////
+void Root::ClearWorlds()
+{
+  this->dataPtr->worlds.clear();
+}

src/Root_TEST.cc

@@ -270,3 +270,45 @@ TEST(DOMRoot, FrameSemanticsOnMove)
     testFrame1(root2);
   }
 }
+
+/////////////////////////////////////////////////
+TEST(DOMRoot, AddWorld)
+{
+  sdf::Root root;
+  EXPECT_EQ(0u, root.WorldCount());
+
+  sdf::World world;
+  world.SetName("world1");
+  EXPECT_TRUE(root.AddWorld(world));
+  EXPECT_EQ(1u, root.WorldCount());
+  EXPECT_FALSE(root.AddWorld(world));
+  EXPECT_EQ(1u, root.WorldCount());
+
+  root.ClearWorlds();
+  EXPECT_EQ(0u, root.WorldCount());
+
+  EXPECT_TRUE(root.AddWorld(world));
+  EXPECT_EQ(1u, root.WorldCount());
+  const sdf::World *worldFromRoot = root.WorldByIndex(0);
+  ASSERT_NE(nullptr, worldFromRoot);
+  EXPECT_EQ(worldFromRoot->Name(), world.Name());
+}
+
+/////////////////////////////////////////////////
+TEST(DOMRoot, MutableByIndex)
+{
+  sdf::Root root;
+  EXPECT_EQ(0u, root.WorldCount());
+
+  sdf::World world;
+  world.SetName("world1");
+  EXPECT_TRUE(root.AddWorld(world));
+  EXPECT_EQ(1u, root.WorldCount());
+
+  // Modify the world
+  sdf::World *w = root.WorldByIndex(0);
+  ASSERT_NE(nullptr, w);
+  EXPECT_EQ("world1", w->Name());
+  w->SetName("world2");
+  EXPECT_EQ("world2", root.WorldByIndex(0)->Name());
+}