text: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   * 
   *   http://www.apache.org/licenses/LICENSE-2.0
   * 
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  
  #include "pagespeed/kernel/cache/fallback_cache.h"
  
  #include "pagespeed/kernel/base/google_message_handler.h"
  #include "pagespeed/kernel/base/string.h"
  #include "pagespeed/kernel/base/string_util.h"
  #include "pagespeed/kernel/cache/cache_interface.h"
  #include "pagespeed/kernel/cache/lru_cache.h"
  #include "test/pagespeed/kernel/base/gtest.h"
  #include "test/pagespeed/kernel/cache/cache_test_base.h"
  
  namespace net_instaweb {
  
  namespace {
  
  const int kTestValueSizeThreshold = 200;
  const int kFallbackCacheSize = 3 * kTestValueSizeThreshold;
  const int kMediumValueSize = kTestValueSizeThreshold - 100;
  const int kLargeWriteSize = kTestValueSizeThreshold + 1;
  const int kHugeWriteSize = 2 * kTestValueSizeThreshold;
  const char kLargeKey1[] = "large1";
  const char kLargeKey2[] = "large2";
  
  }  // namespace
  
  class FallbackCacheTest : public CacheTestBase {
   protected:
    FallbackCacheTest()
        : small_cache_(kFallbackCacheSize),
          large_cache_(kFallbackCacheSize),
          fallback_cache_(&small_cache_, &large_cache_, kTestValueSizeThreshold,
                          &handler_) {}
  
    CacheInterface* Cache() override { return &fallback_cache_; }
  
    GoogleMessageHandler handler_;
    LRUCache small_cache_;
    LRUCache large_cache_;
    FallbackCache fallback_cache_;
  };
  
  // Simple flow of putting in an item, getting it, deleting it.
  TEST_F(FallbackCacheTest, PutGetDelete) {
    CheckPut("Name", "Value");
    CheckGet("Name", "Value");
    CheckNotFound("Another Name");
  
    CheckPut("Name", "NewValue");
    CheckGet("Name", "NewValue");
  
    EXPECT_LT(0, small_cache_.size_bytes()) << "small cache used.";
    EXPECT_EQ(0, large_cache_.size_bytes()) << "large cache not used.";
  
    Cache()->Delete("Name");
    CheckNotFound("Name");
  
    EXPECT_EQ(0, small_cache_.size_bytes());
    EXPECT_EQ(0, large_cache_.size_bytes());
  }
  
  TEST_F(FallbackCacheTest, MultiGet) {
    TestMultiGet();
    EXPECT_EQ(0, large_cache_.size_bytes()) << "fallback not used.";
  }
  
  TEST_F(FallbackCacheTest, BasicInvalid) {
    // Check that we honor callback veto on validity.
    CheckPut("nameA", "valueA");
    CheckPut("nameB", "valueB");
    CheckGet("nameA", "valueA");
    CheckGet("nameB", "valueB");
    set_invalid_value("valueA");
    CheckNotFound("nameA");
    CheckGet("nameB", "valueB");
    EXPECT_EQ(0, large_cache_.size_bytes()) << "fallback not used.";
  }
  
  TEST_F(FallbackCacheTest, LargeInvalid) {
    const GoogleString kValueA(kLargeWriteSize, 'a');
    const GoogleString kValueB(kLargeWriteSize, 'b');
  
    // Check that we honor callback veto on validity.
    CheckPut("nameA", kValueA);
    CheckPut("nameB", kValueB);
    CheckGet("nameA", kValueA);
    CheckGet("nameB", kValueB);
    set_invalid_value(kValueA.c_str());
    CheckNotFound("nameA");
    CheckGet("nameB", kValueB);
    EXPECT_LT(0, large_cache_.size_bytes()) << "fallback was used.";
  }
  
  TEST_F(FallbackCacheTest, SizeTest) {
    for (int x = 0; x < 10; ++x) {
      for (int i = kMediumValueSize / 2; i < kMediumValueSize; ++i) {
        GoogleString value(i, 'a');
        GoogleString key = StrCat("big", IntegerToString(i));
        CheckPut(key, value);
        CheckGet(key, value);
      }
    }
    EXPECT_EQ(0, large_cache_.size_bytes()) << "fallback not used.";
  }
  
  TEST_F(FallbackCacheTest, JustUnderThreshold) {
    const GoogleString kValue(kMediumValueSize, 'a');
    const char kKey[] = "just_under_threshold";
    CheckPut(kKey, kValue);
    CheckGet(kKey, kValue);
    EXPECT_EQ(0, large_cache_.size_bytes()) << "fallback not used.";
  }
  
  TEST_F(FallbackCacheTest, NotCountingKeys) {
    // By default, we do count the keys.
    const char kKey[] = "a";
    const GoogleString kValue(kTestValueSizeThreshold - 1, 'b');
    CheckPut(kKey, kValue);
    CheckGet(kKey, kValue);
    // This should go into large cache (as it's 1 byte over limit due to the
    // key + 1 byte for marker).
    EXPECT_NE(0, large_cache_.size_bytes()) << "fallback used";
  
    small_cache_.Clear();
    large_cache_.Clear();
  
    // If we don't count the key, it should fit in snuggly.
    fallback_cache_.set_account_for_key_size(false);
    CheckPut(kKey, kValue);
    CheckGet(kKey, kValue);
    EXPECT_EQ(0, large_cache_.size_bytes()) << "fallback not used.";
  }
  
  // Basic operation with huge values, only one of which will fit
  // in the fallback cache at a time.
  TEST_F(FallbackCacheTest, HugeValue) {
    const GoogleString kValue(kHugeWriteSize, 'a');
    CheckPut(kLargeKey1, kValue);
    CheckGet(kLargeKey1, kValue);
    EXPECT_LE(kHugeWriteSize, large_cache_.size_bytes());
  
    // Now put in another large value, causing the 1st to get evicted from
    // the large cache.
    CheckPut(kLargeKey2, kValue);
    CheckGet(kLargeKey2, kValue);
    CheckNotFound(kLargeKey1);
  
    // Finally, delete the second value explicitly.
    CheckGet(kLargeKey2, kValue);
    Cache()->Delete(kLargeKey2);
    CheckNotFound(kLargeKey2);
  }
  
  TEST_F(FallbackCacheTest, LargeValueMultiGet) {
    const GoogleString kLargeValue1(kLargeWriteSize, 'a');
    CheckPut(kLargeKey1, kLargeValue1);
    CheckGet(kLargeKey1, kLargeValue1);
    EXPECT_EQ(kLargeWriteSize + STATIC_STRLEN(kLargeKey1),
              large_cache_.size_bytes());
  
    const char kSmallKey[] = "small";
    const char kSmallValue[] = "value";
    CheckPut(kSmallKey, kSmallValue);
  
    const GoogleString kLargeValue2(kLargeWriteSize, 'b');
    CheckPut(kLargeKey2, kLargeValue2);
    CheckGet(kLargeKey2, kLargeValue2);
    EXPECT_LE(2 * kLargeWriteSize, large_cache_.size_bytes())
        << "Checks that both large values were written to the fallback cache";
  
    Callback* large1 = AddCallback();
    Callback* small = AddCallback();
    Callback* large2 = AddCallback();
    IssueMultiGet(large1, kLargeKey1, small, kSmallKey, large2, kLargeKey2);
    WaitAndCheck(large1, kLargeValue1);
    WaitAndCheck(small, "value");
    WaitAndCheck(large2, kLargeValue2);
  }
  
  TEST_F(FallbackCacheTest, MultiLargeSharingSmall) {
    // Make another connection to the same small_cache_, but with a different
    // large_ cache.
    LRUCache large_cache2(kFallbackCacheSize);
    FallbackCache fallback_cache2(&small_cache_, &large_cache2,
                                  kTestValueSizeThreshold, &handler_);
  
    // Now when we store a large object from server1, and fetch it from
    // server2, we will get a miss because they do not share fallback caches..
    // But then we can re-store it and fetch it from either server.
    const GoogleString kLargeValue(kLargeWriteSize, 'a');
    CheckPut(kLargeKey1, kLargeValue);
    CheckGet(kLargeKey1, kLargeValue);
  
    // The large caches are not shared, so we get a miss from fallback_cache2.
    CheckNotFound(&fallback_cache2, kLargeKey1);
  
    CheckPut(&fallback_cache2, kLargeKey1, kLargeValue);
    CheckGet(&fallback_cache2, kLargeKey1, kLargeValue);
    CheckGet(Cache(), kLargeKey1, kLargeValue);
  }
  
  TEST_F(FallbackCacheTest, LargeKeyUnderThreshold) {
    const GoogleString kKey(kMediumValueSize, 'a');
    const char kValue[] = "value";
    CheckPut(kKey, kValue);
    CheckGet(kKey, kValue);
    EXPECT_EQ(0, large_cache_.size_bytes());
  }
  
  // Even keys that are over the *value* threshold can be stored in and
  // retrieved from the fallback cache.
  //
  // Note: we do not expect to see ridiculously large keys; we are just
  // testing for corner cases here.
  TEST_F(FallbackCacheTest, LargeKeyOverThreshold) {
    const GoogleString kKey(kLargeWriteSize, 'a');
    const char kValue[] = "value";
    CheckPut(kKey, kValue);
    CheckGet(kKey, kValue);
    EXPECT_EQ(kKey.size() + STATIC_STRLEN(kValue), large_cache_.size_bytes());
  }
  
  // Tests what happens when we read an empty value, lacking the trailing L
  // or S, from the small cache.
  TEST_F(FallbackCacheTest, EmptyValue) {
    CheckPut(&small_cache_, "key", "");
    CheckNotFound("key");
  }
  
  // Tests what happens when we read a non-empty value, lacking the trailing L
  // or S, from the small cache.
  TEST_F(FallbackCacheTest, CorruptValue) {
    CheckPut(&small_cache_, "key", "garbage");
    CheckNotFound("key");
  }
  
  // If the last-character is 'L', it should be a one-character value.
  TEST_F(FallbackCacheTest, CorruptValueLastCharL) {
    CheckPut(&small_cache_, "key", "xL");
    CheckNotFound("key");
  }
  
  }  // namespace net_instaweb
  