skia/ext/refptr_unittest.cc

   1 // Copyright 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "skia/ext/refptr.h"
   6
   7 #include "testing/gtest/include/gtest/gtest.h"
   8
   9 namespace skia {
  10 namespace {
  11
  12 TEST(RefPtrTest, ReferenceCounting) {
  13   SkRefCnt* ref = new SkRefCnt();
  14   EXPECT_TRUE(ref->unique());
  15
  16   {
  17     // Adopt the reference from the caller on creation.
  18     RefPtr<SkRefCnt> refptr1 = AdoptRef(ref);
  19     EXPECT_TRUE(ref->unique());
  20     EXPECT_TRUE(refptr1->unique());
  21
  22     EXPECT_EQ(ref, &*refptr1);
  23     EXPECT_EQ(ref, refptr1.get());
  24
  25     {
  26       // Take a second reference for the second instance.
  27       RefPtr<SkRefCnt> refptr2(refptr1);
  28       EXPECT_FALSE(ref->unique());
  29
  30       RefPtr<SkRefCnt> refptr3;
  31       EXPECT_FALSE(refptr3);
  32
  33       // Take a third reference for the third instance.
  34       refptr3 = refptr1;
  35       EXPECT_FALSE(ref->unique());
  36
  37       // Same object, so should have the same refcount.
  38       refptr2 = refptr3;
  39       EXPECT_FALSE(ref->unique());
  40
  41       // Drop the object from refptr2, so it should lose its reference.
  42       EXPECT_TRUE(refptr2);
  43       refptr2.clear();
  44       EXPECT_FALSE(ref->unique());
  45
  46       EXPECT_FALSE(refptr2);
  47       EXPECT_EQ(nullptr, refptr2.get());
  48
  49       EXPECT_TRUE(refptr3);
  50       EXPECT_FALSE(refptr3->unique());
  51       EXPECT_EQ(ref, &*refptr3);
  52       EXPECT_EQ(ref, refptr3.get());
  53     }
  54
  55     // Drop a reference when the third object is destroyed.
  56     EXPECT_TRUE(ref->unique());
  57   }
  58 }
  59
  60 TEST(RefPtrTest, Construct) {
  61   SkRefCnt* ref = new SkRefCnt();
  62   EXPECT_TRUE(ref->unique());
  63
  64   // Adopt the reference from the caller on creation.
  65   RefPtr<SkRefCnt> refptr1(AdoptRef(ref));
  66   EXPECT_TRUE(ref->unique());
  67   EXPECT_TRUE(refptr1->unique());
  68
  69   EXPECT_EQ(ref, &*refptr1);
  70   EXPECT_EQ(ref, refptr1.get());
  71
  72   RefPtr<SkRefCnt> refptr2(refptr1);
  73   EXPECT_FALSE(ref->unique());
  74 }
  75
  76 TEST(RefPtrTest, DeclareAndAssign) {
  77   SkRefCnt* ref = new SkRefCnt();
  78   EXPECT_TRUE(ref->unique());
  79
  80   // Adopt the reference from the caller on creation.
  81   RefPtr<SkRefCnt> refptr1 = AdoptRef(ref);
  82   EXPECT_TRUE(ref->unique());
  83   EXPECT_TRUE(refptr1->unique());
  84
  85   EXPECT_EQ(ref, &*refptr1);
  86   EXPECT_EQ(ref, refptr1.get());
  87
  88   RefPtr<SkRefCnt> refptr2 = refptr1;
  89   EXPECT_FALSE(ref->unique());
  90 }
  91
  92 TEST(RefPtrTest, Assign) {
  93   SkRefCnt* ref = new SkRefCnt();
  94   EXPECT_TRUE(ref->unique());
  95
  96   // Adopt the reference from the caller on creation.
  97   RefPtr<SkRefCnt> refptr1;
  98   refptr1 = AdoptRef(ref);
  99   EXPECT_TRUE(ref->unique());
 100   EXPECT_TRUE(refptr1->unique());
 101
 102   EXPECT_EQ(ref, &*refptr1);
 103   EXPECT_EQ(ref, refptr1.get());
 104
 105   RefPtr<SkRefCnt> refptr2;
 106   refptr2 = refptr1;
 107   EXPECT_FALSE(ref->unique());
 108 }
 109
 110 class Subclass : public SkRefCnt {};
 111
 112 TEST(RefPtrTest, Upcast) {
 113   RefPtr<Subclass> child = AdoptRef(new Subclass());
 114   EXPECT_TRUE(child->unique());
 115
 116   RefPtr<SkRefCnt> parent = child;
 117   EXPECT_TRUE(child);
 118   EXPECT_TRUE(parent);
 119
 120   EXPECT_FALSE(child->unique());
 121   EXPECT_FALSE(parent->unique());
 122 }
 123
 124 // Counts the number of ref/unref operations (which require atomic operations)
 125 // that are done.
 126 class RefCountCounter : public SkRefCnt {
 127  public:
 128   void ref() const {
 129     ref_count_changes_++;
 130     SkRefCnt::ref();
 131   }
 132   void unref() const {
 133     ref_count_changes_++;
 134     SkRefCnt::unref();
 135   }
 136   int ref_count_changes() const { return ref_count_changes_; }
 137   void ResetRefCountChanges() { ref_count_changes_ = 0; }
 138
 139  private:
 140   mutable int ref_count_changes_ = 0;
 141 };
 142
 143 TEST(RefPtrTest, ConstructionFromTemporary) {
 144   // No ref count changes to move temporary into a local.
 145   RefPtr<RefCountCounter> object = skia::AdoptRef(new RefCountCounter);
 146   EXPECT_EQ(0, object->ref_count_changes());
 147
 148   // Only one change to share the pointer.
 149   object->ResetRefCountChanges();
 150   RefPtr<RefCountCounter> shared = skia::SharePtr(object.get());
 151   EXPECT_EQ(1, object->ref_count_changes());
 152
 153   // Two ref count changes for the extra ref when passed as an argument, but no
 154   // more.
 155   object->ResetRefCountChanges();
 156   auto do_nothing = [](RefPtr<RefCountCounter>) {};
 157   do_nothing(object);
 158   EXPECT_EQ(2, object->ref_count_changes());
 159
 160   // No ref count changes when passing a newly adopted ref as an argument.
 161   auto lambda = [](RefPtr<RefCountCounter> arg) {
 162     EXPECT_EQ(0, arg->ref_count_changes());
 163   };
 164   lambda(skia::AdoptRef(new RefCountCounter));
 165 }
 166
 167 TEST(RefPtrTest, AssignmentFromTemporary) {
 168   // No ref count changes to move temporary into a local.
 169   RefPtr<RefCountCounter> object;
 170   object = skia::AdoptRef(new RefCountCounter);
 171   EXPECT_EQ(0, object->ref_count_changes());
 172
 173   // Only one change to share the pointer.
 174   object->ResetRefCountChanges();
 175   RefPtr<RefCountCounter> shared;
 176   shared = skia::SharePtr(object.get());
 177   EXPECT_EQ(1, object->ref_count_changes());
 178 }
 179
 180 TEST(RefPtrTest, PassIntoArguments) {
 181   // No ref count changes when passing an argument with Pass().
 182   RefPtr<RefCountCounter> object = skia::AdoptRef(new RefCountCounter);
 183   RefPtr<RefCountCounter> object2 = object.Pass();
 184   auto lambda = [](RefPtr<RefCountCounter> arg) {
 185     EXPECT_EQ(0, arg->ref_count_changes());
 186   };
 187   lambda(object2.Pass());
 188 }
 189
 190 class DestructionNotifier : public SkRefCnt {
 191  public:
 192   DestructionNotifier(bool* flag) : flag_(flag) {}
 193   ~DestructionNotifier() override { *flag_ = true; }
 194
 195  private:
 196   bool* flag_;
 197 };
 198
 199 TEST(RefPtrTest, PassIntoSelf) {
 200   bool is_destroyed = false;
 201   RefPtr<DestructionNotifier> object =
 202       skia::AdoptRef(new DestructionNotifier(&is_destroyed));
 203   object = object.Pass();
 204   ASSERT_FALSE(is_destroyed);
 205   EXPECT_TRUE(object->unique());
 206 }
 207
 208 TEST(RefPtrTest, Nullptr) {
 209   RefPtr<SkRefCnt> null(nullptr);
 210   EXPECT_FALSE(null);
 211
 212   bool is_destroyed = false;
 213   RefPtr<DestructionNotifier> destroy_me =
 214       skia::AdoptRef(new DestructionNotifier(&is_destroyed));
 215   destroy_me = nullptr;
 216   EXPECT_TRUE(is_destroyed);
 217   EXPECT_FALSE(destroy_me);
 218
 219   // Check that returning nullptr from a function correctly causes an implicit
 220   // conversion.
 221   auto lambda = []() -> RefPtr<SkRefCnt> { return nullptr; };
 222   RefPtr<SkRefCnt> returned = lambda();
 223   EXPECT_FALSE(returned);
 224 }
 225
 226 }  // namespace
 227 }  // namespace skia