57 lines
1.4 KiB
C++
57 lines
1.4 KiB
C++
#include "Cache.h"
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#include "PeriodicTask.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 caching {
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constexpr uint32_t Cache::MAX_ENTRIES;
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constexpr double Cache::PURGE_LIFETIME_SEC;
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constexpr double Cache::PURGE_INTERVAL;
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constexpr double Cache::MAX_LIFETIME_SEC;
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Cache::Cache(): _cachedBlocks(), _timeoutFlusher(nullptr) {
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//Don't initialize timeoutFlusher in the initializer list,
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//because it then might already call Cache::popOldEntries() before Cache is done constructing
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_timeoutFlusher = make_unique<PeriodicTask>(std::bind(&Cache::_popOldEntries, this), PURGE_INTERVAL);
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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.pop(key);
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if (found.get() == nullptr) {
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return nullptr;
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}
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auto block = found->releaseBlock();
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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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assert(_cachedBlocks.size() <= MAX_ENTRIES);
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if (_cachedBlocks.size() == MAX_ENTRIES) {
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_cachedBlocks.pop();
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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.push(key, make_unique<CacheEntry>(std::move(block)));
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}
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void Cache::_popOldEntries() {
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lock_guard<mutex> lock(_mutex);
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while(_cachedBlocks.size() > 0 && _cachedBlocks.peek().ageSeconds() > PURGE_LIFETIME_SEC) {
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_cachedBlocks.pop();
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}
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}
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}
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}
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