1 files changed, 159 insertions, 0 deletions
diff --git a/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp b/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp
new file mode 100644
index 00000000000..c3d7b874c36
--- /dev/null
+++ b/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp
@@ -0,0 +1,159 @@
+// Copyright 2016 Yahoo Inc. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#include <vespa/fastos/fastos.h>
+#include <vespa/log/log.h>
+LOG_SETUP("generationhandler_test");
+#include <vespa/vespalib/testkit/testapp.h>
+#include <vespa/vespalib/util/generationhandler.h>
+#include <deque>
+
+namespace vespalib {
+
+typedef GenerationHandler::Guard GenGuard;
+
+class Test : public vespalib::TestApp {
+private:
+    void requireThatGenerationCanBeIncreased();
+    void requireThatReadersCanTakeGuards();
+    void requireThatGuardsCanBeCopied();
+    void requireThatTheFirstUsedGenerationIsCorrect();
+    void requireThatGenerationCanGrowLarge();
+public:
+    int Main();
+};
+
+void
+Test::requireThatGenerationCanBeIncreased()
+{
+    GenerationHandler gh;
+    EXPECT_EQUAL(0u, gh.getCurrentGeneration());
+    EXPECT_EQUAL(0u, gh.getFirstUsedGeneration());
+    gh.incGeneration();
+    EXPECT_EQUAL(1u, gh.getCurrentGeneration());
+    EXPECT_EQUAL(1u, gh.getFirstUsedGeneration());
+}
+
+void
+Test::requireThatReadersCanTakeGuards()
+{
+    GenerationHandler gh;
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount(0));
+    {
+        GenGuard g1 = gh.takeGuard();
+        EXPECT_EQUAL(1u, gh.getGenerationRefCount(0));
+        {
+            GenGuard g2 = gh.takeGuard();
+            EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+            gh.incGeneration();
+            {
+                GenGuard g3 = gh.takeGuard();
+                EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+                EXPECT_EQUAL(1u, gh.getGenerationRefCount(1));
+                EXPECT_EQUAL(3u, gh.getGenerationRefCount());
+            }
+            EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+            EXPECT_EQUAL(0u, gh.getGenerationRefCount(1));
+            gh.incGeneration();
+            {
+                GenGuard g3 = gh.takeGuard();
+                EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+                EXPECT_EQUAL(0u, gh.getGenerationRefCount(1));
+                EXPECT_EQUAL(1u, gh.getGenerationRefCount(2));
+            }
+            EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+            EXPECT_EQUAL(0u, gh.getGenerationRefCount(1));
+            EXPECT_EQUAL(0u, gh.getGenerationRefCount(2));
+        }
+        EXPECT_EQUAL(1u, gh.getGenerationRefCount(0));
+        EXPECT_EQUAL(0u, gh.getGenerationRefCount(1));
+        EXPECT_EQUAL(0u, gh.getGenerationRefCount(2));
+    }
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount(0));
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount(1));
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount(2));
+}
+
+void
+Test::requireThatGuardsCanBeCopied()
+{
+    GenerationHandler gh;
+    GenGuard g1 = gh.takeGuard();
+    EXPECT_EQUAL(1u, gh.getGenerationRefCount(0));
+    GenGuard g2(g1);
+    EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+    gh.incGeneration();
+    GenGuard g3 = gh.takeGuard();
+    EXPECT_EQUAL(2u, gh.getGenerationRefCount(0));
+    EXPECT_EQUAL(1u, gh.getGenerationRefCount(1));
+    g3 = g2;
+    EXPECT_EQUAL(3u, gh.getGenerationRefCount(0));
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount(1));
+}
+
+void
+Test::requireThatTheFirstUsedGenerationIsCorrect()
+{
+    GenerationHandler gh;
+    EXPECT_EQUAL(0u, gh.getFirstUsedGeneration());
+    gh.incGeneration();
+    EXPECT_EQUAL(1u, gh.getFirstUsedGeneration());
+    {
+        GenGuard g1 = gh.takeGuard();
+        gh.incGeneration();
+        EXPECT_EQUAL(true, gh.hasReaders());
+        EXPECT_EQUAL(1u, gh.getFirstUsedGeneration());
+    }
+    EXPECT_EQUAL(1u, gh.getFirstUsedGeneration());
+    gh.updateFirstUsedGeneration();	// Only writer should call this
+    EXPECT_EQUAL(false, gh.hasReaders());
+    EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
+    {
+        GenGuard g1 = gh.takeGuard();
+        gh.incGeneration();
+        gh.incGeneration();
+        EXPECT_EQUAL(true, gh.hasReaders());
+        EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
+        {
+            GenGuard g2 = gh.takeGuard();
+            EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
+        }
+    }
+    EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
+    gh.updateFirstUsedGeneration();	// Only writer should call this
+    EXPECT_EQUAL(false, gh.hasReaders());
+    EXPECT_EQUAL(4u, gh.getFirstUsedGeneration());
+}
+
+void
+Test::requireThatGenerationCanGrowLarge()
+{
+    GenerationHandler gh;
+    std::deque<GenGuard> guards;
+    for (size_t i = 0; i < 10000; ++i) {
+        EXPECT_EQUAL(i, gh.getCurrentGeneration());
+        guards.push_back(gh.takeGuard()); // take guard on current generation
+        if (i >= 128) {
+            EXPECT_EQUAL(i - 128, gh.getFirstUsedGeneration());
+            guards.pop_front();
+            EXPECT_EQUAL(128u, gh.getGenerationRefCount());
+        }
+        gh.incGeneration();
+    }
+}
+
+int
+Test::Main()
+{
+    TEST_INIT("generationhandler_test");
+
+    TEST_DO(requireThatGenerationCanBeIncreased());
+    TEST_DO(requireThatReadersCanTakeGuards());
+    TEST_DO(requireThatGuardsCanBeCopied());
+    TEST_DO(requireThatTheFirstUsedGenerationIsCorrect());
+    TEST_DO(requireThatGenerationCanGrowLarge());
+
+    TEST_DONE();
+}
+
+}
+
+TEST_APPHOOK(vespalib::Test);