From 11fa4b939d176da02580e4a7f397bdd7c7179e4f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pasindu=20Gunasekara=20=F0=9F=8D=A3?=
 <pgunasekara@microsoft.com>
Date: Wed, 9 Feb 2022 21:29:20 +0000
Subject: [PATCH] Merged PR 648568: Detours - Avoid allocating memory in
 PathTree destructor

- Avoids allocating wstring and vectors in the destructor

Related work items: #1913787
---
 .../Sandbox/Windows/DetoursServices/PathTree.cpp | 16 +++++++++++++---
 .../Sandbox/Windows/DetoursServices/PathTree.h   |  3 +++
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/Public/Src/Sandbox/Windows/DetoursServices/PathTree.cpp b/Public/Src/Sandbox/Windows/DetoursServices/PathTree.cpp
index 20084092e..3a871e983 100644
--- a/Public/Src/Sandbox/Windows/DetoursServices/PathTree.cpp
+++ b/Public/Src/Sandbox/Windows/DetoursServices/PathTree.cpp
@@ -23,9 +23,7 @@ PathTree::PathTree()
 
 PathTree::~PathTree()
 {
-    std::vector<std::wstring> descendants;
-    RetrieveAndRemoveAllDescendants(L"", m_root, descendants);
-
+    RemoveAllDescendants(m_root);
     delete m_root;
 }
 
@@ -159,6 +157,18 @@ void PathTree::RetrieveAndRemoveAllDescendants(const std::wstring& path, TreeNod
     node->children.clear();
 }
 
+void PathTree::RemoveAllDescendants(TreeNode* node)
+{
+    for (auto iter = node->children.begin(); iter != node->children.end(); iter++)
+    {
+        RemoveAllDescendants(iter->second);
+
+        delete iter->second;
+    }
+
+    node->children.clear();
+}
+
 bool PathTree::TryFind(const std::wstring& path, std::vector<std::pair<std::wstring, TreeNode*>>& nodeTrace)
 {
     std::vector<std::wstring> elements;
diff --git a/Public/Src/Sandbox/Windows/DetoursServices/PathTree.h b/Public/Src/Sandbox/Windows/DetoursServices/PathTree.h
index 788f1213f..82f0442fc 100644
--- a/Public/Src/Sandbox/Windows/DetoursServices/PathTree.h
+++ b/Public/Src/Sandbox/Windows/DetoursServices/PathTree.h
@@ -56,6 +56,9 @@ private:
     // Removes all descendants from the given node and builds the descendants collection using the given path as a prefix
     void RetrieveAndRemoveAllDescendants(const std::wstring& path, TreeNode* lastNode, std::vector<std::wstring>& descendants);
 
+    // Removes all descendants from the given node
+    void RemoveAllDescendants(TreeNode* node);
+
     // Debugging facility
     std::wstring ToDebugString(TreeNode* node = nullptr, std::wstring ident = L"");