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author | dgrogan@chromium.org <dgrogan@chromium.org@62dab493-f737-651d-591e-8d6aee1b9529> | 2011-04-19 23:01:25 +0000 |
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committer | dgrogan@chromium.org <dgrogan@chromium.org@62dab493-f737-651d-591e-8d6aee1b9529> | 2011-04-19 23:01:25 +0000 |
commit | b743906eeabc925f3e824d91a9747012bf249e2f (patch) | |
tree | e7cb4f854196c43045756469627920e4e7b146c1 /table/two_level_iterator.cc | |
parent | b409afe968b6917574ec08e02c4bf6e6f722e3ca (diff) | |
download | leveldb-b743906eeabc925f3e824d91a9747012bf249e2f.tar.gz |
Revision created by MOE tool push_codebase.
MOE_MIGRATION=
git-svn-id: https://leveldb.googlecode.com/svn/trunk@22 62dab493-f737-651d-591e-8d6aee1b9529
Diffstat (limited to 'table/two_level_iterator.cc')
-rw-r--r-- | table/two_level_iterator.cc | 182 |
1 files changed, 0 insertions, 182 deletions
diff --git a/table/two_level_iterator.cc b/table/two_level_iterator.cc deleted file mode 100644 index 24a1241..0000000 --- a/table/two_level_iterator.cc +++ /dev/null @@ -1,182 +0,0 @@ -// Copyright (c) 2011 The LevelDB Authors. All rights reserved. -// Use of this source code is governed by a BSD-style license that can be -// found in the LICENSE file. See the AUTHORS file for names of contributors. - -#include "table/two_level_iterator.h" - -#include "leveldb/table.h" -#include "table/block.h" -#include "table/format.h" -#include "table/iterator_wrapper.h" - -namespace leveldb { - -namespace { - -typedef Iterator* (*BlockFunction)(void*, const ReadOptions&, const Slice&); - -class TwoLevelIterator: public Iterator { - public: - TwoLevelIterator( - Iterator* index_iter, - BlockFunction block_function, - void* arg, - const ReadOptions& options); - - virtual ~TwoLevelIterator(); - - virtual void Seek(const Slice& target); - virtual void SeekToFirst(); - virtual void SeekToLast(); - virtual void Next(); - virtual void Prev(); - - virtual bool Valid() const { - return data_iter_.Valid(); - } - virtual Slice key() const { - assert(Valid()); - return data_iter_.key(); - } - virtual Slice value() const { - assert(Valid()); - return data_iter_.value(); - } - virtual Status status() const { - // It'd be nice if status() returned a const Status& instead of a Status - if (!index_iter_.status().ok()) { - return index_iter_.status(); - } else if (data_iter_.iter() != NULL && !data_iter_.status().ok()) { - return data_iter_.status(); - } else { - return status_; - } - } - - private: - void SaveError(const Status& s) { - if (status_.ok() && !s.ok()) status_ = s; - } - void SkipEmptyDataBlocksForward(); - void SkipEmptyDataBlocksBackward(); - void SetDataIterator(Iterator* data_iter); - void InitDataBlock(); - - BlockFunction block_function_; - void* arg_; - const ReadOptions options_; - Status status_; - IteratorWrapper index_iter_; - IteratorWrapper data_iter_; // May be NULL - // If data_iter_ is non-NULL, then "data_block_handle_" holds the - // "index_value" passed to block_function_ to create the data_iter_. - std::string data_block_handle_; -}; - -TwoLevelIterator::TwoLevelIterator( - Iterator* index_iter, - BlockFunction block_function, - void* arg, - const ReadOptions& options) - : block_function_(block_function), - arg_(arg), - options_(options), - index_iter_(index_iter), - data_iter_(NULL) { -} - -TwoLevelIterator::~TwoLevelIterator() { -} - -void TwoLevelIterator::Seek(const Slice& target) { - index_iter_.Seek(target); - InitDataBlock(); - if (data_iter_.iter() != NULL) data_iter_.Seek(target); - SkipEmptyDataBlocksForward(); -} - -void TwoLevelIterator::SeekToFirst() { - index_iter_.SeekToFirst(); - InitDataBlock(); - if (data_iter_.iter() != NULL) data_iter_.SeekToFirst(); - SkipEmptyDataBlocksForward(); -} - -void TwoLevelIterator::SeekToLast() { - index_iter_.SeekToLast(); - InitDataBlock(); - if (data_iter_.iter() != NULL) data_iter_.SeekToLast(); - SkipEmptyDataBlocksBackward(); -} - -void TwoLevelIterator::Next() { - assert(Valid()); - data_iter_.Next(); - SkipEmptyDataBlocksForward(); -} - -void TwoLevelIterator::Prev() { - assert(Valid()); - data_iter_.Prev(); - SkipEmptyDataBlocksBackward(); -} - - -void TwoLevelIterator::SkipEmptyDataBlocksForward() { - while (data_iter_.iter() == NULL || !data_iter_.Valid()) { - // Move to next block - if (!index_iter_.Valid()) { - SetDataIterator(NULL); - return; - } - index_iter_.Next(); - InitDataBlock(); - if (data_iter_.iter() != NULL) data_iter_.SeekToFirst(); - } -} - -void TwoLevelIterator::SkipEmptyDataBlocksBackward() { - while (data_iter_.iter() == NULL || !data_iter_.Valid()) { - // Move to next block - if (!index_iter_.Valid()) { - SetDataIterator(NULL); - return; - } - index_iter_.Prev(); - InitDataBlock(); - if (data_iter_.iter() != NULL) data_iter_.SeekToLast(); - } -} - -void TwoLevelIterator::SetDataIterator(Iterator* data_iter) { - if (data_iter_.iter() != NULL) SaveError(data_iter_.status()); - data_iter_.Set(data_iter); -} - -void TwoLevelIterator::InitDataBlock() { - if (!index_iter_.Valid()) { - SetDataIterator(NULL); - } else { - Slice handle = index_iter_.value(); - if (data_iter_.iter() != NULL && handle.compare(data_block_handle_) == 0) { - // data_iter_ is already constructed with this iterator, so - // no need to change anything - } else { - Iterator* iter = (*block_function_)(arg_, options_, handle); - data_block_handle_.assign(handle.data(), handle.size()); - SetDataIterator(iter); - } - } -} - -} - -Iterator* NewTwoLevelIterator( - Iterator* index_iter, - BlockFunction block_function, - void* arg, - const ReadOptions& options) { - return new TwoLevelIterator(index_iter, block_function, arg, options); -} - -} |