| // Copyright 2018 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "components/previews/content/hint_cache.h" |
| |
| #include <algorithm> |
| |
| #include "base/bind.h" |
| #include "url/gurl.h" |
| |
| namespace previews { |
| |
| namespace { |
| |
| // Realistic minimum length of a host suffix. |
| const int kMinHostSuffix = 6; // eg., abc.tv |
| |
| // The default number of hints retained within the memory cache. When the limit |
| // is exceeded, the least recently used hint is purged from the cache. |
| const size_t kDefaultMaxMemoryCacheHints = 20; |
| |
| } // namespace |
| |
| HintCache::HintCache( |
| std::unique_ptr<HintCacheStore> hint_store, |
| base::Optional<int> max_memory_cache_hints /*= base::Optional<int>()*/) |
| : hint_store_(std::move(hint_store)), |
| memory_cache_( |
| std::max(max_memory_cache_hints.value_or(kDefaultMaxMemoryCacheHints), |
| 1)) { |
| DCHECK(hint_store_); |
| } |
| |
| HintCache::~HintCache() = default; |
| |
| void HintCache::Initialize(bool purge_existing_data, |
| base::OnceClosure callback) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| hint_store_->Initialize( |
| purge_existing_data, |
| base::BindOnce(&HintCache::OnStoreInitialized, base::Unretained(this), |
| std::move(callback))); |
| } |
| |
| std::unique_ptr<HintCacheStore::ComponentUpdateData> |
| HintCache::MaybeCreateComponentUpdateData(const base::Version& version) const { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| return hint_store_->MaybeCreateComponentUpdateData(version); |
| } |
| |
| void HintCache::UpdateComponentData( |
| std::unique_ptr<HintCacheStore::ComponentUpdateData> component_data, |
| base::OnceClosure callback) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(component_data); |
| |
| // Clear the memory cache prior to updating the store with the new component |
| // data. |
| memory_cache_.Clear(); |
| |
| hint_store_->UpdateComponentData(std::move(component_data), |
| std::move(callback)); |
| } |
| |
| bool HintCache::HasHint(const std::string& host) const { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| HintCacheStore::EntryKey hint_entry_key; |
| return FindHintEntryKey(host, &hint_entry_key); |
| } |
| |
| void HintCache::LoadHint(const std::string& host, HintLoadedCallback callback) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| HintCacheStore::EntryKey hint_entry_key; |
| if (!FindHintEntryKey(host, &hint_entry_key)) { |
| std::move(callback).Run(nullptr); |
| return; |
| } |
| |
| // Search for the entry key in the memory cache; if it is not already there, |
| // then asynchronously load it from the store and return. |
| auto hint_it = memory_cache_.Get(hint_entry_key); |
| if (hint_it == memory_cache_.end()) { |
| hint_store_->LoadHint( |
| hint_entry_key, |
| base::BindOnce(&HintCache::OnLoadStoreHint, base::Unretained(this), |
| std::move(callback))); |
| return; |
| } |
| |
| // Run the callback with the hint from the memory cache. |
| std::move(callback).Run(hint_it->second.get()); |
| } |
| |
| const optimization_guide::proto::Hint* HintCache::GetHintIfLoaded( |
| const std::string& host) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| |
| // Try to retrieve the hint entry key for the host. If no hint exists for the |
| // host, then simply return. |
| HintCacheStore::EntryKey hint_entry_key; |
| if (!FindHintEntryKey(host, &hint_entry_key)) { |
| return nullptr; |
| } |
| |
| // Find the hint within the memory cache. It will only be available here if |
| // it has been loaded recently enough to be retained within the MRU cache. |
| auto hint_it = memory_cache_.Get(hint_entry_key); |
| if (hint_it != memory_cache_.end()) { |
| return hint_it->second.get(); |
| } |
| |
| return nullptr; |
| } |
| |
| void HintCache::OnStoreInitialized(base::OnceClosure callback) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| std::move(callback).Run(); |
| } |
| |
| void HintCache::OnLoadStoreHint( |
| HintLoadedCallback callback, |
| const HintCacheStore::EntryKey& hint_entry_key, |
| std::unique_ptr<optimization_guide::proto::Hint> hint) { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| if (!hint) { |
| std::move(callback).Run(nullptr); |
| return; |
| } |
| |
| // Check if the hint was cached in memory after the load was requested from |
| // the store. This can occur if multiple loads for the same entry key occur |
| // consecutively prior to any returning. |
| auto hint_it = memory_cache_.Get(hint_entry_key); |
| if (hint_it == memory_cache_.end()) { |
| hint_it = memory_cache_.Put(hint_entry_key, std::move(hint)); |
| } |
| |
| std::move(callback).Run(hint_it->second.get()); |
| } |
| |
| bool HintCache::FindHintEntryKey( |
| const std::string& host, |
| HintCacheStore::EntryKey* out_hint_entry_key) const { |
| DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_); |
| DCHECK(out_hint_entry_key); |
| |
| // Look for longest host name suffix that has a hint. No need to continue |
| // lookups and substring work once get to a root domain like ".com" or |
| // ".co.in" (MinHostSuffix length check is a heuristic for that). |
| std::string host_suffix(host); |
| while (host_suffix.length() >= kMinHostSuffix) { |
| // Attempt to find a hint entry key associated with the current host suffix |
| // within the store. |
| if (hint_store_->FindHintEntryKey(host_suffix, out_hint_entry_key)) { |
| return true; |
| } |
| |
| size_t pos = host_suffix.find_first_of('.'); |
| if (pos == std::string::npos) { |
| break; |
| } |
| host_suffix = host_suffix.substr(pos + 1); |
| } |
| return false; |
| } |
| |
| } // namespace previews |