From 1623de8bd07e801333aa954d3cb195c0a296fa71 Mon Sep 17 00:00:00 2001
From: Daniel Agar <daniel@agar.ca>
Date: Tue, 11 Jun 2019 14:38:28 -0400
Subject: [PATCH] IntrusiveQueue add remove method, iterators, and update test

---
 src/include/containers/IntrusiveQueue.hpp    | 52 ++++++++++++++++++
 src/systemcmds/tests/test_IntrusiveQueue.cpp | 57 ++++++++++++++++++++
 2 files changed, 109 insertions(+)

diff --git a/src/include/containers/IntrusiveQueue.hpp b/src/include/containers/IntrusiveQueue.hpp
index 100017cd29..47f2099725 100644
--- a/src/include/containers/IntrusiveQueue.hpp
+++ b/src/include/containers/IntrusiveQueue.hpp
@@ -95,6 +95,58 @@ public:
 		return ret;
 	}
 
+	bool remove(T removeNode)
+	{
+		// base case
+		if (removeNode == _head) {
+			if (_head->next_intrusive_queue_node() != nullptr) {
+				_head = _head->next_intrusive_queue_node();
+
+			} else {
+				_head = nullptr;
+			}
+
+			return true;
+		}
+
+		for (T node = _head; node != nullptr; node = node->next_intrusive_queue_node()) {
+			// is sibling the node to remove?
+			if (node->next_intrusive_queue_node() == removeNode) {
+				// replace sibling
+				if (node->next_intrusive_queue_node() != nullptr) {
+					node->set_next_intrusive_queue_node(node->next_intrusive_queue_node()->next_intrusive_queue_node());
+
+				} else {
+					node->set_next_intrusive_queue_node(nullptr);
+				}
+
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	struct Iterator {
+		T node;
+		Iterator(T v) : node(v) {}
+
+		operator T() const { return node; }
+		operator T &() { return node; }
+		T operator* () const { return node; }
+		Iterator &operator++ ()
+		{
+			if (node) {
+				node = node->next_intrusive_queue_node();
+			};
+
+			return *this;
+		}
+	};
+
+	Iterator begin() { return Iterator(_head); }
+	Iterator end() { return Iterator(nullptr); }
+
 private:
 
 	T _head{nullptr};
diff --git a/src/systemcmds/tests/test_IntrusiveQueue.cpp b/src/systemcmds/tests/test_IntrusiveQueue.cpp
index d82f7607f4..6c7005cc1d 100644
--- a/src/systemcmds/tests/test_IntrusiveQueue.cpp
+++ b/src/systemcmds/tests/test_IntrusiveQueue.cpp
@@ -50,6 +50,7 @@ public:
 	bool test_push();
 	bool test_pop();
 	bool test_push_duplicate();
+	bool test_remove();
 
 };
 
@@ -58,6 +59,7 @@ bool IntrusiveQueueTest::run_tests()
 	ut_run_test(test_push);
 	ut_run_test(test_pop);
 	ut_run_test(test_push_duplicate);
+	ut_run_test(test_remove);
 
 	return (_tests_failed == 0);
 }
@@ -211,4 +213,59 @@ bool IntrusiveQueueTest::test_push_duplicate()
 	return true;
 }
 
+bool IntrusiveQueueTest::test_remove()
+{
+	IntrusiveQueue<testContainer *> q1;
+
+	// size should be 0 initially
+	ut_compare("size initially 0", q1.size(), 0);
+	ut_assert_true(q1.empty());
+
+	// insert 100
+	for (int i = 0; i < 100; i++) {
+		testContainer *t = new testContainer();
+		t->i = i;
+		q1.push(t);
+
+		ut_compare("size increasing with i", q1.size(), i + 1);
+		ut_assert_true(!q1.empty());
+	}
+
+	// verify full size (100)
+	ut_assert_true(q1.size() == 100);
+
+	// test removing elements
+	for (int remove_i = 0; remove_i < 100; remove_i++) {
+
+		// find node with i == remove_i
+		for (auto t : q1) {
+			if (t->i == remove_i) {
+				ut_assert_true(q1.remove(t));
+			}
+		}
+
+		// iterate list again to verify removal
+		for (auto t : q1) {
+			ut_assert_true(t->i != remove_i);
+		}
+
+		ut_assert_true(q1.size() == 100 - remove_i - 1);
+	}
+
+	// list should now be empty
+	ut_assert_true(q1.empty());
+	ut_compare("size 0", q1.size(), 0);
+
+	// delete all elements (should be safe on empty list)
+	while (!q1.empty()) {
+		q1.pop();
+	}
+
+	// verify list has been cleared
+	ut_assert_true(q1.empty());
+	ut_compare("size 0", q1.size(), 0);
+
+	return true;
+}
+
 ut_declare_test_c(test_IntrusiveQueue, IntrusiveQueueTest)