1 files changed, 185 insertions, 0 deletions
diff --git a/gfx/tests/gtest/TestArena.cpp b/gfx/tests/gtest/TestArena.cpp
new file mode 100644
index 0000000000..7f9aad6592
--- /dev/null
+++ b/gfx/tests/gtest/TestArena.cpp
@@ -0,0 +1,185 @@
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+
+#include "gtest/gtest.h"
+#include "gmock/gmock.h"
+
+#include "mozilla/gfx/IterableArena.h"
+#include <string>
+
+using namespace mozilla;
+using namespace mozilla::gfx;
+
+#ifdef A
+#  undef A
+#endif
+
+#ifdef B
+#  undef B
+#endif
+
+// to avoid having symbols that collide easily like A and B in the global
+// namespace
+namespace test_arena {
+
+class A;
+class B;
+
+class Base {
+ public:
+  virtual ~Base() = default;
+  virtual A* AsA() { return nullptr; }
+  virtual B* AsB() { return nullptr; }
+};
+
+static int sDtorItemA = 0;
+static int sDtorItemB = 0;
+
+class A : public Base {
+ public:
+  virtual A* AsA() override { return this; }
+
+  explicit A(uint64_t val) : mVal(val) {}
+  ~A() { ++sDtorItemA; }
+
+  uint64_t mVal;
+};
+
+class B : public Base {
+ public:
+  virtual B* AsB() override { return this; }
+
+  explicit B(const std::string& str) : mVal(str) {}
+  ~B() { ++sDtorItemB; }
+
+  std::string mVal;
+};
+
+struct BigStruct {
+  uint64_t mVal;
+  uint8_t data[120];
+
+  explicit BigStruct(uint64_t val) : mVal(val) {}
+};
+
+static void TestArenaAlloc(IterableArena::ArenaType aType) {
+  sDtorItemA = 0;
+  sDtorItemB = 0;
+  IterableArena arena(aType, 256);
+
+  // An empty arena has no items to iterate over.
+  {
+    int iterations = 0;
+    arena.ForEach([&](void* item) { iterations++; });
+    ASSERT_EQ(iterations, 0);
+  }
+
+  auto a1 = arena.Alloc<A>(42);
+  auto b1 = arena.Alloc<B>("Obladi oblada");
+  auto a2 = arena.Alloc<A>(1337);
+  auto b2 = arena.Alloc<B>("Yellow submarine");
+  auto b3 = arena.Alloc<B>("She's got a ticket to ride");
+
+  // Alloc returns a non-negative offset if the allocation succeeded.
+  ASSERT_TRUE(a1 >= 0);
+  ASSERT_TRUE(a2 >= 0);
+  ASSERT_TRUE(b1 >= 0);
+  ASSERT_TRUE(b2 >= 0);
+  ASSERT_TRUE(b3 >= 0);
+
+  ASSERT_TRUE(arena.GetStorage(a1) != nullptr);
+  ASSERT_TRUE(arena.GetStorage(a2) != nullptr);
+  ASSERT_TRUE(arena.GetStorage(b1) != nullptr);
+  ASSERT_TRUE(arena.GetStorage(b2) != nullptr);
+  ASSERT_TRUE(arena.GetStorage(b3) != nullptr);
+
+  ASSERT_TRUE(((Base*)arena.GetStorage(a1))->AsA() != nullptr);
+  ASSERT_TRUE(((Base*)arena.GetStorage(a2))->AsA() != nullptr);
+
+  ASSERT_TRUE(((Base*)arena.GetStorage(b1))->AsB() != nullptr);
+  ASSERT_TRUE(((Base*)arena.GetStorage(b2))->AsB() != nullptr);
+  ASSERT_TRUE(((Base*)arena.GetStorage(b3))->AsB() != nullptr);
+
+  ASSERT_EQ(((Base*)arena.GetStorage(a1))->AsA()->mVal, (uint64_t)42);
+  ASSERT_EQ(((Base*)arena.GetStorage(a2))->AsA()->mVal, (uint64_t)1337);
+
+  ASSERT_EQ(((Base*)arena.GetStorage(b1))->AsB()->mVal,
+            std::string("Obladi oblada"));
+  ASSERT_EQ(((Base*)arena.GetStorage(b2))->AsB()->mVal,
+            std::string("Yellow submarine"));
+  ASSERT_EQ(((Base*)arena.GetStorage(b3))->AsB()->mVal,
+            std::string("She's got a ticket to ride"));
+
+  {
+    int iterations = 0;
+    arena.ForEach([&](void* item) { iterations++; });
+    ASSERT_EQ(iterations, 5);
+  }
+
+  // Typically, running the destructors of the elements in the arena will is
+  // done manually like this:
+  arena.ForEach([](void* item) { ((Base*)item)->~Base(); });
+  arena.Clear();
+  ASSERT_EQ(sDtorItemA, 2);
+  ASSERT_EQ(sDtorItemB, 3);
+
+  // An empty arena has no items to iterate over (we just cleared it).
+  {
+    int iterations = 0;
+    arena.ForEach([&](void* item) { iterations++; });
+    ASSERT_EQ(iterations, 0);
+  }
+}
+
+static void TestArenaLimit(IterableArena::ArenaType aType,
+                           bool aShouldReachLimit) {
+  IterableArena arena(aType, 128);
+
+  // A non-growable arena should return a negative offset when running out
+  // of space, without crashing.
+  // We should not run out of space with a growable arena (unless the os is
+  // running out of memory but this isn't expected for this test).
+  bool reachedLimit = false;
+  for (int i = 0; i < 100; ++i) {
+    auto offset = arena.Alloc<A>(42);
+    if (offset < 0) {
+      reachedLimit = true;
+      break;
+    }
+  }
+  ASSERT_EQ(reachedLimit, aShouldReachLimit);
+}
+
+}  // namespace test_arena
+
+using namespace test_arena;
+
+TEST(Moz2D, FixedArena)
+{
+  TestArenaAlloc(IterableArena::FIXED_SIZE);
+  TestArenaLimit(IterableArena::FIXED_SIZE, true);
+}
+
+TEST(Moz2D, GrowableArena)
+{
+  TestArenaAlloc(IterableArena::GROWABLE);
+  TestArenaLimit(IterableArena::GROWABLE, false);
+
+  IterableArena arena(IterableArena::GROWABLE, 16);
+  // sizeof(BigStruct) is more than twice the initial capacity, make sure that
+  // this doesn't blow everything up, since the arena doubles its storage size
+  // each time it grows (until it finds a size that fits).
+  auto a = arena.Alloc<BigStruct>(1);
+  auto b = arena.Alloc<BigStruct>(2);
+  auto c = arena.Alloc<BigStruct>(3);
+
+  // Offsets should also still point to the appropriate values after
+  // reallocation.
+  ASSERT_EQ(((BigStruct*)arena.GetStorage(a))->mVal, (uint64_t)1);
+  ASSERT_EQ(((BigStruct*)arena.GetStorage(b))->mVal, (uint64_t)2);
+  ASSERT_EQ(((BigStruct*)arena.GetStorage(c))->mVal, (uint64_t)3);
+
+  arena.Clear();
+}