1 files changed, 104 insertions, 0 deletions
diff --git a/dom/xslt/base/txStack.h b/dom/xslt/base/txStack.h
new file mode 100644
index 0000000000..83c91ae49d
--- /dev/null
+++ b/dom/xslt/base/txStack.h
@@ -0,0 +1,104 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef txStack_h___
+#define txStack_h___
+
+#include "nsTArray.h"
+
+class txStack : private nsTArray<void*> {
+ public:
+  /**
+   * Returns the specified object from the top of this stack,
+   * without removing it from the stack.
+   *
+   * @return a pointer to the object that is the top of this stack.
+   */
+  inline void* peek() {
+    NS_ASSERTION(!isEmpty(), "peeking at empty stack");
+    return !isEmpty() ? ElementAt(Length() - 1) : nullptr;
+  }
+
+  /**
+   * Adds the specified object to the top of this stack.
+   *
+   * @param obj a pointer to the object that is to be added to the
+   * top of this stack.
+   */
+  inline nsresult push(void* aObject) {
+    // XXX(Bug 1631371) Check if this should use a fallible operation as it
+    // pretended earlier, or change the return type to void.
+    AppendElement(aObject);
+    return NS_OK;
+  }
+
+  /**
+   * Removes and returns the specified object from the top of this
+   * stack.
+   *
+   * @return a pointer to the object that was the top of this stack.
+   */
+  inline void* pop() {
+    void* object = nullptr;
+    NS_ASSERTION(!isEmpty(), "popping from empty stack");
+    if (!isEmpty()) {
+      object = PopLastElement();
+    }
+    return object;
+  }
+
+  /**
+   * Returns true if there are no objects in the stack.
+   *
+   * @return true if there are no objects in the stack.
+   */
+  inline bool isEmpty() { return IsEmpty(); }
+
+  /**
+   * Returns the number of elements in the Stack.
+   *
+   * @return the number of elements in the Stack.
+   */
+  inline int32_t size() { return Length(); }
+
+ private:
+  friend class txStackIterator;
+};
+
+class txStackIterator {
+ public:
+  /**
+   * Creates an iterator for the given stack.
+   *
+   * @param aStack the stack to create an iterator for.
+   */
+  inline explicit txStackIterator(txStack* aStack)
+      : mStack(aStack), mPosition(0) {}
+
+  /**
+   * Returns true if there is more objects on the stack.
+   *
+   * @return .
+   */
+  inline bool hasNext() { return (mPosition < mStack->Length()); }
+
+  /**
+   * Returns the next object pointer from the stack.
+   *
+   * @return .
+   */
+  inline void* next() {
+    if (mPosition == mStack->Length()) {
+      return nullptr;
+    }
+    return mStack->ElementAt(mPosition++);
+  }
+
+ private:
+  txStack* mStack;
+  uint32_t mPosition;
+};
+
+#endif /* txStack_h___ */