RefCount: Add a unit test for reference counting pointers.

This test exercises each of the functions in the reference counting pointer
implementation individually (except get()) and verifies they have some
minimially expected behavior. It also checks that reference counted objects
are freed when their usage count goes to 0 in some basic situations,
specifically a pointer being set to NULL and a pointer being deleted.

src/unittest/SConscript

@@ -44,6 +44,7 @@ UnitTest('offtest', 'offtest.cc')
 UnitTest('rangetest', 'rangetest.cc')
 UnitTest('rangemaptest', 'rangemaptest.cc')
 UnitTest('rangemultimaptest', 'rangemultimaptest.cc')
+UnitTest('refcnttest', 'refcnttest.cc')
 UnitTest('stattest', 'stattest.cc')
 UnitTest('strnumtest', 'strnumtest.cc')
 UnitTest('symtest', 'symtest.cc')

src/unittest/refcnttest.cc

@@ -0,0 +1,187 @@
+/*
+ * Copyright (c) 2010 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Gabe Black
+ */
+
+#include <cassert>
+#include <iostream>
+#include <list>
+
+#include "base/refcnt.hh"
+
+using namespace std;
+
+namespace {
+
+class TestRC;
+typedef list<TestRC *> LiveList;
+LiveList liveList;
+
+int
+live()
+{
+    return liveList.size();
+}
+
+int
+liveChange()
+{
+    static int oldLive = 0;
+    int newLive = live();
+    int diff =  newLive - oldLive;
+    oldLive = newLive;
+    return diff;
+}
+
+class TestRC : public RefCounted
+{
+  protected:
+    const char *_tag;
+    LiveList::iterator liveIt;
+
+  public:
+    TestRC(const char *newTag) : _tag(newTag)
+    {
+        cout << "  Creating object \"" << _tag << "\"\n";
+        liveList.push_front(this);
+        liveIt = liveList.begin();
+    }
+
+    ~TestRC()
+    {
+        cout << "  Destroying object \"" << _tag << "\"\n";
+        liveList.erase(liveIt);
+    }
+
+    const char *
+    tag()
+    {
+        return _tag;
+    }
+
+    int testVal;
+};
+
+typedef RefCountingPtr<TestRC> Ptr;
+
+}
+
+int
+main()
+{
+    assert(live() == 0);
+    assert(liveChange() == 0);
+
+    // Create an empty Ptr and verify it's data pointer is NULL.
+    cout << "NULL check.\n";
+    Ptr nullCheck;
+    assert(nullCheck.get() == NULL);
+
+    assert(liveChange() == 0);
+
+    // Construct a Ptr from a TestRC pointer.
+    cout << "Construction from pointer.\n";
+    Ptr constFromPointer = new TestRC("construction from pointer");
+
+    assert(liveChange() == 1);
+
+    // Construct a Ptr from an existing Ptr.
+    cout << "Construction from a Ptr.\n";
+    Ptr constFromPtr = constFromPointer;
+
+    assert(liveChange() == 0);
+
+    // Test a Ptr being destroyed.
+    cout << "Destroying a Ptr.\n";
+    Ptr *ptrPtr = new Ptr(new TestRC("destroying a ptr"));
+    assert(liveChange() == 1);
+    delete ptrPtr;
+    assert(liveChange() == -1);
+
+    // Test assignment from a pointer and from a Ptr.
+    cout << "Assignment operators.\n";
+    Ptr assignmentTarget;
+    TestRC *assignmentSourcePointer = new TestRC("assignment source 1");
+    assert(liveChange() == 1);
+    assignmentTarget = assignmentSourcePointer;
+    assert(liveChange() == 0);
+    assignmentTarget = NULL;
+    assert(liveChange() == -1);
+    Ptr assignmentSourcePtr(new TestRC("assignment source 2"));
+    assert(liveChange() == 1);
+    assignmentTarget = assignmentSourcePtr;
+    assert(liveChange() == 0);
+    assignmentSourcePtr = NULL;
+    assert(liveChange() == 0);
+    assignmentTarget = NULL;
+    assert(liveChange() == -1);
+
+    // Test access to members of the pointed to class and dereferencing.
+    cout << "Access to members.\n";
+    TestRC *accessTest = new TestRC("access test");
+    Ptr accessTestPtr = accessTest;
+    accessTest->testVal = 1;
+    assert(accessTestPtr->testVal == 1);
+    assert((*accessTestPtr).testVal == 1);
+    accessTest->testVal = 2;
+    assert(accessTestPtr->testVal == 2);
+    assert((*accessTestPtr).testVal == 2);
+    accessTestPtr->testVal = 3;
+    assert(accessTest->testVal == 3);
+    (*accessTestPtr).testVal = 4;
+    assert(accessTest->testVal == 4);
+    accessTestPtr = NULL;
+    accessTest = NULL;
+    assert(liveChange() == 0);
+
+    // Test bool and ! operator overloads.
+    cout << "Conversion to bool and ! overload.\n";
+    Ptr boolTest = new TestRC("bool test");
+    assert(boolTest == true);
+    assert(!boolTest == false);
+    boolTest = NULL;
+    assert(boolTest == false);
+    assert(!boolTest == true);
+    assert(liveChange() == 0);
+
+    // Test the equality operators.
+    cout << "Equality operators.\n";
+    TestRC *equalTestA = new TestRC("equal test a");
+    Ptr equalTestAPtr = equalTestA;
+    Ptr equalTestAPtr2 = equalTestA;
+    TestRC *equalTestB = new TestRC("equal test b");
+    Ptr equalTestBPtr = equalTestB;
+    assert(equalTestA == equalTestAPtr);
+    assert(equalTestAPtr == equalTestA);
+    assert(equalTestAPtr == equalTestAPtr2);
+    assert(equalTestA != equalTestBPtr);
+    assert(equalTestAPtr != equalTestB);
+    assert(equalTestAPtr != equalTestBPtr);
+
+    cout << flush;
+}