51 lines
1.2 KiB
C++
51 lines
1.2 KiB
C++
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#include "Cache.h"
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using std::unique_ptr;
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using std::make_unique;
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using std::mutex;
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using std::lock_guard;
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using std::pair;
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namespace blockstore {
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namespace caching2 {
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constexpr uint32_t Cache::MAX_ENTRIES;
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Cache::Cache(): _cachedBlocks() {
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}
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Cache::~Cache() {
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}
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unique_ptr<Block> Cache::pop(const Key &key) {
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lock_guard<mutex> lock(_mutex);
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auto found = _cachedBlocks.find(key);
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if (found == _cachedBlocks.end()) {
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return nullptr;
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}
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auto block = found->second.releaseBlock();
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_cachedBlocks.erase(found);
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return block;
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}
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void Cache::push(unique_ptr<Block> block) {
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lock_guard<mutex> lock(_mutex);
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if (_cachedBlocks.size() > MAX_ENTRIES) {
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deleteOldestEntry();
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assert(_cachedBlocks.size() == MAX_ENTRIES-1);
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}
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Key key = block->key();
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_cachedBlocks.emplace(key, std::move(block));
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}
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void Cache::deleteOldestEntry() {
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auto oldestEntry = std::min_element(_cachedBlocks.begin(), _cachedBlocks.end(), [] (const pair<const Key, CacheEntry> &lhs, const pair<const Key, CacheEntry> &rhs) {
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return lhs.second.ageSeconds() > rhs.second.ageSeconds();
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});
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//printf("Deleting age %f (vs %f)\n", oldestEntry->second.ageSeconds(), _cachedBlocks.begin()->second.ageSeconds());
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_cachedBlocks.erase(oldestEntry);
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}
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}
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}
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