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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
#pragma once
#include "postinglistcounts.h"
#include "postinglisthandle.h"
#include "postinglistparams.h"
#include <vespa/searchlib/common/tunefileinfo.h>
class FastOS_FileInterface;
namespace search::common { class FileHeaderContext; }
namespace search::index {
class DocIdAndFeatures;
/**
* Interface for posting list files containing document ids and features
* for words.
*/
class PostingListFileSeqRead {
protected:
PostingListCounts _counts;
unsigned int _residueDocs; // Docids left to read for word
public:
PostingListFileSeqRead();
virtual ~PostingListFileSeqRead();
/**
* Read document id and features.
*/
virtual void readDocIdAndFeatures(DocIdAndFeatures &features) = 0;
/**
* Read counts for a word.
*/
virtual void readCounts(const PostingListCounts &counts) = 0;
/**
* Open posting list file for sequential read.
*/
virtual bool open(const vespalib::string &name, const TuneFileSeqRead &tuneFileRead) = 0;
/**
* Close posting list file.
*/
virtual bool close() = 0;
/*
* Get current parameters.
*/
virtual void getParams(PostingListParams ¶ms);
/*
* Set (word, docid) feature parameters.
*
* Typically can only enable or disable cooked features.
*/
virtual void setFeatureParams(const PostingListParams ¶ms);
/*
* Get current (word, docid) feature parameters.
*/
virtual void getFeatureParams(PostingListParams ¶ms);
// Methods used when generating posting list for common word pairs.
/*
* Get current posting offset, measured in bits. First posting list
* starts at 0, i.e. file header is not accounted for here.
*
* @return current posting offset, measured in bits.
*/
virtual uint64_t getCurrentPostingOffset() const = 0;
/**
* Set current posting offset, measured in bits. First posting
* list starts at 0, i.e. file header is not accounted for here.
*
* @param Offset start of posting lists for word pair.
* @param endOffset end of posting lists for word pair.
* @param readAheadOffset end of posting list for either this or a
* later word pair, depending on disk seek cost.
*/
virtual void setPostingOffset(uint64_t offset, uint64_t endOffset, uint64_t readAheadOffset) = 0;
/**
* Get counts read by last readCounts().
*/
const PostingListCounts &getCounts() const { return _counts; }
PostingListCounts &getCounts() { return _counts; }
};
/**
* Interface for posting list files containing document ids and features
* for words.
*/
class PostingListFileSeqWrite {
protected:
PostingListCounts _counts;
public:
PostingListFileSeqWrite();
virtual ~PostingListFileSeqWrite();
/**
* Write document id and features.
*/
virtual void writeDocIdAndFeatures(const DocIdAndFeatures &features) = 0;
/**
* Flush word (during write) after it is complete to buffers, i.e.
* prepare for next word, but not for application crash.
*/
virtual void flushWord() = 0;
/**
* Open posting list file for sequential write.
*/
virtual bool
open(const vespalib::string &name,
const TuneFileSeqWrite &tuneFileWrite,
const common::FileHeaderContext &fileHeaderContext) = 0;
/**
* Close posting list file.
*/
virtual bool close() = 0;
/*
* Set parameters.
*/
virtual void setParams(const PostingListParams ¶ms);
/*
* Get current parameters.
*/
virtual void getParams(PostingListParams ¶ms);
/*
* Set (word, docid) feature parameters.
*/
virtual void setFeatureParams(const PostingListParams ¶ms);
/*
* Get current (word, docid) feature parameters.
*/
virtual void getFeatureParams(PostingListParams ¶ms);
PostingListCounts &getCounts() { return _counts; }
};
/**
* Interface for posting list files containing document ids and features
* for words.
*/
class PostingListFileRandRead {
protected:
// Can be examined after open
bool _memoryMapped;
public:
typedef std::shared_ptr<PostingListFileRandRead> SP;
PostingListFileRandRead();
virtual ~PostingListFileRandRead();
/**
* Create iterator for single word. Semantic lifetime of counts and
* handle must exceed lifetime of iterator.
*
* XXX: TODO: How to read next set of segments from disk if handle
* didn't cover the whole word, probably need access to higher level
* API above caches.
*/
virtual search::queryeval::SearchIterator *
createIterator(const PostingListCounts &counts,
const PostingListHandle &handle,
const search::fef::TermFieldMatchDataArray &matchData,
bool usebitVector) const = 0;
/**
* Read (possibly partial) posting list into handle.
*/
virtual void
readPostingList(const PostingListCounts &counts,
uint32_t firstSegment,
uint32_t numSegments,
PostingListHandle &handle) = 0;
/**
* Open posting list file for random read.
*/
virtual bool open(const vespalib::string &name, const TuneFileRandRead &tuneFileRead) = 0;
/**
* Close posting list file.
*/
virtual bool close() = 0;
bool getMemoryMapped() const { return _memoryMapped; }
protected:
void afterOpen(FastOS_FileInterface &file);
};
/**
* Passthrough class.
*/
class PostingListFileRandReadPassThrough : public PostingListFileRandRead {
protected:
PostingListFileRandRead *_lower;
bool _ownLower;
public:
PostingListFileRandReadPassThrough(PostingListFileRandRead *lower, bool ownLower);
~PostingListFileRandReadPassThrough();
search::queryeval::SearchIterator *
createIterator(const PostingListCounts &counts,
const PostingListHandle &handle,
const search::fef::TermFieldMatchDataArray &matchData,
bool usebitVector) const override;
void readPostingList(const PostingListCounts &counts, uint32_t firstSegment,
uint32_t numSegments, PostingListHandle &handle) override;
bool open(const vespalib::string &name, const TuneFileRandRead &tuneFileRead) override;
bool close() override;
};
}
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