Summary: also add an override option total_order_iteration if you want to use full iterator with prefix_extractor Test Plan: make all check Reviewers: igor, haobo, sdong, yhchiang Reviewed By: haobo CC: leveldb, dhruba Differential Revision: https://reviews.facebook.net/D17805main
Lei Jin
11 years ago
parent
8ce5492623
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3995e801ab
@ -1,75 +0,0 @@ |
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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Wrap an underlying iterator, but exclude any results not starting
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// with a given prefix. Seeking to keys not beginning with the prefix
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// is invalid, and SeekToLast is not implemented (that would be
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// non-trivial), but otherwise this iterator will behave just like the
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// underlying iterator would if there happened to be no non-matching
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// keys in the dataset.
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#pragma once |
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#include "rocksdb/iterator.h" |
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#include "rocksdb/slice.h" |
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#include "rocksdb/slice_transform.h" |
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namespace rocksdb { |
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class PrefixFilterIterator : public Iterator { |
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private: |
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Iterator* iter_; |
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const Slice &prefix_; |
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const SliceTransform *prefix_extractor_; |
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Status status_; |
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public: |
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PrefixFilterIterator(Iterator* iter, |
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const Slice &prefix, |
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const SliceTransform* prefix_extractor) |
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: iter_(iter), prefix_(prefix), |
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prefix_extractor_(prefix_extractor), |
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status_(Status::OK()) { |
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if (prefix_extractor == nullptr) { |
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status_ = Status::InvalidArgument("A prefix filter may not be used " |
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"unless a function is also defined " |
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"for extracting prefixes"); |
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} else if (!prefix_extractor_->InRange(prefix)) { |
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status_ = Status::InvalidArgument("Must provide a slice for prefix which" |
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"is a prefix for some key"); |
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} |
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} |
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~PrefixFilterIterator() { |
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delete iter_; |
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} |
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Slice key() const { return iter_->key(); } |
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Slice value() const { return iter_->value(); } |
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Status status() const { |
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if (!status_.ok()) { |
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return status_; |
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} |
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return iter_->status(); |
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} |
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void Next() { iter_->Next(); } |
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void Prev() { iter_->Prev(); } |
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void Seek(const Slice& k) { |
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if (prefix_extractor_->Transform(k) == prefix_) { |
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iter_->Seek(k); |
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} else { |
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status_ = Status::InvalidArgument("Seek must begin with target prefix"); |
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} |
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} |
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void SeekToFirst() { |
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Seek(prefix_); |
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} |
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void SeekToLast() { |
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status_ = Status::NotSupported("SeekToLast is incompatible with prefixes"); |
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} |
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bool Valid() const { |
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return (status_.ok() && iter_->Valid() && |
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prefix_extractor_->Transform(iter_->key()) == prefix_); |
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} |
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}; |
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} // namespace rocksdb
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