// Copyright 2018 The PDFium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "core/fxcrt/autorestorer.h"
#include "core/fxcrt/retain_ptr.h"
#include "core/fxcrt/unowned_ptr.h"
#include "testing/gtest/include/gtest/gtest.h"
#include "testing/pseudo_retainable.h"

TEST(fxcrt, AutoRestorer) {
  int x = 5;
  {
    AutoRestorer<int> restorer(&x);
    x = 6;
    EXPECT_EQ(6, x);
  }
  EXPECT_EQ(5, x);
}

TEST(fxcrt, AutoRestorerNoOp) {
  int x = 5;
  {
    AutoRestorer<int> restorer(&x);
    EXPECT_EQ(5, x);
  }
  EXPECT_EQ(5, x);
}

TEST(fxcrt, AutoRestorerAbandon) {
  int x = 5;
  {
    AutoRestorer<int> restorer(&x);
    x = 6;
    EXPECT_EQ(6, x);
    restorer.AbandonRestoration();
  }
  EXPECT_EQ(6, x);
}

TEST(fxcrt, AutoRestorerUnownedPtr) {
  int x = 5;
  int y = 6;
  UnownedPtr<int> ptr(&x);
  {
    AutoRestorer<UnownedPtr<int>> restorer(&ptr);
    ptr = &y;
    EXPECT_EQ(&y, ptr);
  }
  EXPECT_EQ(&x, ptr);
}

TEST(fxcrt, AutoRestorerUnownedNoOp) {
  int x = 5;
  UnownedPtr<int> ptr(&x);
  {
    AutoRestorer<UnownedPtr<int>> restorer(&ptr);
    EXPECT_EQ(&x, ptr);
  }
  EXPECT_EQ(&x, ptr);
}

TEST(fxcrt, AutoRestorerUnownedPtrAbandon) {
  int x = 5;
  int y = 6;
  UnownedPtr<int> ptr(&x);
  {
    AutoRestorer<UnownedPtr<int>> restorer(&ptr);
    ptr = &y;
    EXPECT_EQ(&y, ptr);
    restorer.AbandonRestoration();
  }
  EXPECT_EQ(&y, ptr);
}

TEST(fxcrt, AutoRestorerRetainPtr) {
  PseudoRetainable obj1;
  PseudoRetainable obj2;
  RetainPtr<PseudoRetainable> ptr(&obj1);
  EXPECT_EQ(1, obj1.retain_count());
  EXPECT_EQ(0, obj1.release_count());
  {
    AutoRestorer<RetainPtr<PseudoRetainable>> restorer(&ptr);
    // |obj1| is kept alive by restorer in case it need to be restored.
    EXPECT_EQ(2, obj1.retain_count());
    EXPECT_EQ(0, obj1.release_count());
    ptr.Reset(&obj2);
    EXPECT_EQ(&obj2, ptr.Get());

    // |obj1| released by |ptr| assignment.
    EXPECT_TRUE(obj1.alive());
    EXPECT_EQ(2, obj1.retain_count());
    EXPECT_EQ(1, obj1.release_count());

    // |obj2| now kept alive by |ptr|.
    EXPECT_TRUE(obj1.alive());
    EXPECT_EQ(1, obj2.retain_count());
    EXPECT_EQ(0, obj2.release_count());
  }
  EXPECT_EQ(&obj1, ptr.Get());

  // |obj1| now kept alive again by |ptr|.
  EXPECT_TRUE(obj1.alive());
  EXPECT_EQ(3, obj1.retain_count());
  EXPECT_EQ(2, obj1.release_count());

  // |obj2| dead.
  EXPECT_FALSE(obj2.alive());
  EXPECT_EQ(1, obj2.retain_count());
  EXPECT_EQ(1, obj2.release_count());
}

TEST(fxcrt, AutoRestorerRetainPtrNoOp) {
  PseudoRetainable obj1;
  RetainPtr<PseudoRetainable> ptr(&obj1);
  EXPECT_EQ(1, obj1.retain_count());
  EXPECT_EQ(0, obj1.release_count());
  {
    AutoRestorer<RetainPtr<PseudoRetainable>> restorer(&ptr);
    EXPECT_EQ(2, obj1.retain_count());
    EXPECT_EQ(0, obj1.release_count());
  }
  EXPECT_EQ(&obj1, ptr.Get());

  // Self-reassignement avoided ref churn.
  EXPECT_TRUE(obj1.alive());
  EXPECT_EQ(2, obj1.retain_count());
  EXPECT_EQ(1, obj1.release_count());
}

TEST(fxcrt, AutoRestorerRetainPtrAbandon) {
  PseudoRetainable obj1;
  PseudoRetainable obj2;
  RetainPtr<PseudoRetainable> ptr(&obj1);
  EXPECT_EQ(1, obj1.retain_count());
  EXPECT_EQ(0, obj1.release_count());
  {
    AutoRestorer<RetainPtr<PseudoRetainable>> restorer(&ptr);
    // |obj1| is kept alive by restorer in case it need to be restored.
    EXPECT_EQ(2, obj1.retain_count());
    EXPECT_EQ(0, obj1.release_count());
    ptr.Reset(&obj2);
    EXPECT_EQ(&obj2, ptr.Get());

    // |obj1| released by |ptr| assignment.
    EXPECT_EQ(2, obj1.retain_count());
    EXPECT_EQ(1, obj1.release_count());

    // |obj2| now kept alive by |ptr|.
    EXPECT_EQ(1, obj2.retain_count());
    EXPECT_EQ(0, obj2.release_count());

    restorer.AbandonRestoration();
  }
  EXPECT_EQ(&obj2, ptr.Get());

  // |obj1| now dead as a result of abandonment.
  EXPECT_FALSE(obj1.alive());
  EXPECT_EQ(2, obj1.retain_count());
  EXPECT_EQ(2, obj1.release_count());

  // |obj2| kept alive by |ptr|.
  EXPECT_TRUE(obj2.alive());
  EXPECT_EQ(1, obj2.retain_count());
  EXPECT_EQ(0, obj2.release_count());
}