Leveldb源码分析之过滤器(三) —-InternalFilterPolicy
InternalFilterPolicy是对FilterPolicy的一个封装，将InternalKey转为UserKey。
2.创建过滤器
先将Key转为UserKey，然后再创建过滤器
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void InternalFilterPolicy::CreateFilter(const Slice* keys, int n, std::string* dst) const { // We rely on the fact that the code in table.cc does not mind us // adjusting keys[]. Slice* mkey = const_cast<Slice*>(keys); for (int i = 0; i < n; i++) { mkey[i] = ExtractUserKey(keys[i]); // TODO(sanjay): Suppress dups? } user_policy_->CreateFilter(keys, n, dst); } |
3.判断Key是否在Filter中
先将InternalKey转为UserKey，再判断
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bool InternalFilterPolicy::KeyMayMatch(const Slice& key, const Slice& f) const { return user_policy_->KeyMayMatch(ExtractUserKey(key), f); } |
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