From 6d682ab7ebaa8e0db0124e672343c84397517bf8 Mon Sep 17 00:00:00 2001
From: Chris Roberts <croberts@hashicorp.com>
Date: Wed, 6 Oct 2021 08:41:30 -0700
Subject: [PATCH] Add simple stack implementation

---
 .../commands/serve/mappers/internal/stack.rb  | 45 +++++++++++++++++++
 1 file changed, 45 insertions(+)
 create mode 100644 plugins/commands/serve/mappers/internal/stack.rb

diff --git a/plugins/commands/serve/mappers/internal/stack.rb b/plugins/commands/serve/mappers/internal/stack.rb
new file mode 100644
index 000000000..fbf0bd8b4
--- /dev/null
+++ b/plugins/commands/serve/mappers/internal/stack.rb
@@ -0,0 +1,45 @@
+module VagrantPlugins
+  module CommandServe
+    class Mappers
+      module Internal
+        # Simple stack implementation
+        class Stack
+          def initialize
+            @data = []
+            @m = Mutex.new
+          end
+
+          def include?(v)
+            @m.synchronize do
+              @data.include?(v)
+            end
+          end
+
+          def pop
+            @m.synchronize do
+              @data.pop
+            end
+          end
+
+          def push(v)
+            @m.synchronize do
+              @data.push(v)
+            end
+          end
+
+          def size
+            @m.synchronize do
+              @data.size
+            end
+          end
+
+          def values
+            @m.synchronize do
+              @data.dup
+            end
+          end
+        end
+      end
+    end
+  end
+end