Merge pull request #28 from aesophor/divide-by-zero-fix

Fix issue #24: fix divide by zero in Workspace::DfsTileHelper()

src/tree.cc

@@ -38,25 +38,7 @@ Tree::Node* Tree::GetTreeNode(Client* client) const {
 }
 
 vector<Tree::Node*> Tree::GetLeaves() const {
-  vector<Tree::Node*> leaves;
-  stack<Tree::Node*> st;
-  st.push(root_node_.get());
-
-  while (!st.empty()) {
-    Tree::Node* node = st.top();
-    st.pop();
-
-    // If this node is a leaf, add it to the leaf vector.
-    if (node->children().empty()) {
-      leaves.push_back(node);
-    }
-
-    // Push all children onto the stack in reverse order (if any).
-    for (int i = node->children().size() - 1; i >= 0; i--) {
-      st.push(node->children().at(i));
-    }
-  }
-  return leaves;
+  return root_node_->GetLeaves();
 }
 
 Tree::Node* Tree::root_node() const {
@@ -243,6 +225,39 @@ Tree::Node* Tree::Node::GetRightSibling() const {
   }
 }
 
+vector<Tree::Node*> Tree::Node::GetLeaves() {
+  vector<Tree::Node*> leaves;
+  stack<Tree::Node*> st;
+  st.push(this);
+
+  while (!st.empty()) {
+    Tree::Node* node = st.top();
+    st.pop();
+
+    // If this node is a leaf, add it to the leaf vector.
+    if (node->children().empty()) {
+      leaves.push_back(node);
+    }
+
+    // Push all children onto the stack in reverse order (if any).
+    for (int i = node->children().size() - 1; i >= 0; i--) {
+      st.push(node->children().at(i));
+    }
+  }
+  return leaves;
+}
+
+bool Tree::Node::HasTilingClientsInSubtree() {
+  // Get all leaves from this node's subtree,
+  // and check if it has any tiling client.
+  for (auto leaf : this->GetLeaves()) {
+    if (!leaf->client()->is_floating()) {
+      return true;
+    }
+  }
+  return false;
+}
+
 vector<Tree::Node*> Tree::Node::children() const {
   vector<Tree::Node*> children(children_.size());
   for (size_t i = 0; i < children.size(); i++) {

src/tree.h

@@ -33,6 +33,9 @@ class Tree {
     Tree::Node* GetLeftSibling() const;
     Tree::Node* GetRightSibling() const;
 
+    std::vector<Tree::Node*> GetLeaves();
+    bool HasTilingClientsInSubtree();
+
     std::vector<Tree::Node*> children() const;
     Tree::Node* parent() const;
     Client* client() const;

src/workspace.cc

@@ -137,11 +137,17 @@ void Workspace::DfsTileHelper(Tree::Node* node, int x, int y, int w, int h, int
                               int gap_width) const {
   vector<Tree::Node*> children = node->children();
 
-  // We don't care about floating windows. Remove them.
-  children.erase(
-      std::remove_if(children.begin(), children.end(),
-                     [](Tree::Node* n) { return n->client() && n->client()->is_floating(); }),
-      children.end());
+  // We don't care about two kinds of `Tree::Node`s
+  // 1. an internal node with no tiling clients in its subtree
+  // 2. a leaf but it has a floating client
+  // Tree::Node::HasTilingClientsInSubtree() can check 1 and 2 at the same time.
+  children.erase(std::remove_if(children.begin(), children.end(),
+                                [](Tree::Node* n) { return !n->HasTilingClientsInSubtree(); }),
+                 children.end());
+
+  if (children.empty()) {
+    return;
+  }
 
   // Calculate each child's x, y, width and height based on node's tiling
   // direction.
@@ -177,6 +183,13 @@ void Workspace::SetTilingDirection(TilingDirection tiling_direction) {
 
   Tree::Node* current_node = client_tree_.current_node();
 
+  // If current node has no siblings, we can simply set the new
+  // tiling direction on its parent and return.
+  if (current_node->parent()->children().size() == 1) {
+    current_node->parent()->set_tiling_direction(tiling_direction);
+    return;
+  }
+
   unique_ptr<Client> client(current_node->release_client());
   unique_ptr<Tree::Node> new_node = std::make_unique<Tree::Node>(std::move(client));