Abstract base class for leaf postlists. More...

#include <leafpostlist.h>

Inheritance diagram for LeafPostList:

Collaboration diagram for LeafPostList:

Public Member Functions
	~LeafPostList ()

void	set_termweight (const Xapian::Weight *weight_)
	Set the weighting scheme to use during matching. More...

double	resolve_lazy_termweight (Xapian::Weight weight_, Xapian::Weight::Internal stats, Xapian::termcount qlen, Xapian::termcount wqf, double factor)

virtual Xapian::doccount	get_termfreq () const =0
	Return the exact term frequency. More...

Xapian::doccount	get_termfreq_min () const
	Get a lower bound on the number of documents indexed by this term. More...

Xapian::doccount	get_termfreq_max () const
	Get an upper bound on the number of documents indexed by this term. More...

Xapian::doccount	get_termfreq_est () const
	Get an estimate of the number of documents indexed by this term. More...

double	get_maxweight () const
	Return an upper bound on what get_weight() can return. More...

double	get_weight () const
	Return the weight contribution for the current position. More...

double	recalc_maxweight ()
	Recalculate the upper bound on what get_weight() can return. More...

TermFreqs	get_termfreq_est_using_stats (const Xapian::Weight::Internal &stats) const
	Get an estimate for the termfreq and reltermfreq, given the stats. More...

Xapian::termcount	count_matching_subqs () const
	Count the number of leaf subqueries which match at the current position. More...

void	gather_position_lists (OrPositionList *orposlist)
	Gather PositionList* objects for a subtree. More...

virtual LeafPostList *	open_nearby_postlist (const std::string &term_) const
	Open another postlist from the same database. More...

virtual Xapian::termcount	get_wdf_upper_bound () const =0

void	set_term (const std::string &term_)
	Set the term name. More...

Public Member Functions inherited from Xapian::PostingIterator::Internal
virtual	~Internal ()
	We have virtual methods and want to be able to delete derived classes using a pointer to the base class, so we need a virtual destructor. More...

virtual Xapian::docid	get_docid () const =0
	Return the current docid. More...

virtual Xapian::termcount	get_doclength () const =0
	Return the length of current document. More...

virtual Xapian::termcount	get_unique_terms () const =0
	Return the number of unique terms in the current document. More...

virtual Xapian::termcount	get_wdf () const
	Return the wdf for the document at the current position. More...

virtual const std::string *	get_sort_key () const

virtual const std::string *	get_collapse_key () const
	If the collapse key is already known, return it. More...

virtual bool	at_end () const =0
	Return true if the current position is past the last entry in this list. More...

virtual PositionList *	read_position_list ()
	Read the position list for the term in the current document and return a pointer to it (owned by the PostList). More...

virtual PositionList *	open_position_list () const
	Read the position list for the term in the current document and return a pointer to it (not owned by the PostList). More...

virtual Internal *	next (double w_min)=0
	Advance the current position to the next document in the postlist. More...

virtual Internal *	skip_to (Xapian::docid did, double w_min)=0
	Skip forward to the specified docid. More...

virtual Internal *	check (Xapian::docid did, double w_min, bool &valid)
	Check if the specified docid occurs in this postlist. More...

Internal *	next ()
	Advance the current position to the next document in the postlist. More...

Internal *	skip_to (Xapian::docid did)
	Skip forward to the specified docid. More...

virtual std::string	get_description () const =0
	Return a string description of this object. More...

Public Member Functions inherited from Xapian::Internal::intrusive_base
	intrusive_base ()
	Construct with no references. More...

Protected Member Functions
	LeafPostList (const std::string &term_)
	Only constructable as a base class for derived classes. More...

Protected Member Functions inherited from Xapian::PostingIterator::Internal
	Internal ()
	Only constructable as a base class for derived classes. More...

Protected Attributes
const Xapian::Weight *	weight

bool	need_doclength

bool	need_unique_terms

std::string	term
	The term name for this postlist (empty for an alldocs postlist). More...

Private Member Functions
void	operator= (const LeafPostList &)
	Don't allow assignment. More...

	LeafPostList (const LeafPostList &)
	Don't allow copying. More...

Additional Inherited Members
Public Attributes inherited from Xapian::Internal::intrusive_base
unsigned	_refs
	Reference count. More...

Detailed Description

Abstract base class for leaf postlists.

This class provides the following features in addition to the PostList class:

Definition at line 39 of file leafpostlist.h.

Constructor & Destructor Documentation

◆ LeafPostList() [1/2]

LeafPostList::LeafPostList ( const LeafPostList & )

private

Don't allow copying.

◆ LeafPostList() [2/2]

LeafPostList::LeafPostList ( const std::string & term_ )

inlineexplicitprotected

Only constructable as a base class for derived classes.

Definition at line 55 of file leafpostlist.h.

◆ ~LeafPostList()

LeafPostList::~LeafPostList ( )

Definition at line 33 of file leafpostlist.cc.

Member Function Documentation

◆ count_matching_subqs()

Xapian::termcount LeafPostList::count_matching_subqs ( ) const

virtual

Count the number of leaf subqueries which match at the current position.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 110 of file leafpostlist.cc.

◆ gather_position_lists()

void LeafPostList::gather_position_lists ( OrPositionList * orposlist )

virtual

Gather PositionList* objects for a subtree.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 116 of file leafpostlist.cc.

References OrPositionList::add_poslist().

◆ get_maxweight()

double LeafPostList::get_maxweight ( ) const

virtual

Return an upper bound on what get_weight() can return.

Implements Xapian::PostingIterator::Internal.

Definition at line 67 of file leafpostlist.cc.

Referenced by recalc_maxweight().

◆ get_termfreq()

virtual Xapian::doccount LeafPostList::get_termfreq ( ) const

pure virtual

Return the exact term frequency.

Leaf postlists have an exact termfreq, which get_termfreq_min(), get_termfreq_max(), and get_termfreq_est() all report.

Implemented in ChertPostList, InMemoryAllDocsPostList, GlassPostList, InMemoryPostList, NetworkPostList, ChertModifiedPostList, ContiguousAllDocsPostList, ChertAllDocsPostList, and GlassAllDocsPostList.

Referenced by LocalSubMatch::open_post_list().

◆ get_termfreq_est()

Xapian::doccount LeafPostList::get_termfreq_est ( ) const

virtual

Get an estimate of the number of documents indexed by this term.

It should always be true that: get_termfreq_min() <= get_termfreq_est() <= get_termfreq_max()

Implements Xapian::PostingIterator::Internal.

Definition at line 51 of file leafpostlist.cc.

◆ get_termfreq_est_using_stats()

TermFreqs LeafPostList::get_termfreq_est_using_stats ( const Xapian::Weight::Internal & stats ) const

virtual

Get an estimate for the termfreq and reltermfreq, given the stats.

The frequencies may be for a combination of databases, or for just the relevant documents, so the results need not lie in the bounds given by get_termfreq_min() and get_termfreq_max().

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 95 of file leafpostlist.cc.

References Assert, Xapian::Weight::Internal::collection_size, LOGCALL, RETURN, Xapian::Weight::Internal::rset_size, Xapian::Weight::Internal::termfreqs, and Xapian::Weight::Internal::total_length.

◆ get_termfreq_max()

Xapian::doccount LeafPostList::get_termfreq_max ( ) const

virtual

Get an upper bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 45 of file leafpostlist.cc.

◆ get_termfreq_min()

Xapian::doccount LeafPostList::get_termfreq_min ( ) const

virtual

Get a lower bound on the number of documents indexed by this term.

Implements Xapian::PostingIterator::Internal.

Definition at line 39 of file leafpostlist.cc.

◆ get_wdf_upper_bound()

virtual Xapian::termcount LeafPostList::get_wdf_upper_bound ( ) const

pure virtual

Implemented in ChertPostList, GlassPostList, InMemoryAllDocsPostList, InMemoryPostList, NetworkPostList, and ContiguousAllDocsPostList.

Referenced by Xapian::Weight::init_().

◆ get_weight()

double LeafPostList::get_weight ( ) const

virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 73 of file leafpostlist.cc.

References AssertRel.

◆ open_nearby_postlist()

LeafPostList * LeafPostList::open_nearby_postlist ( const std::string & term_ ) const

virtual

Open another postlist from the same database.

Parameters

term_ The term to open a postlist for. If term_ is near to this postlist's term, then this can be a lot more efficient (and if it isn't very near, there's not much of a penalty). Using this method can make a wildcard expansion much more memory efficient.

Returns: The new postlist object, or NULL if not supported (in which case the caller should probably open the postlist via the database instead).

Reimplemented in GlassPostList.

Definition at line 122 of file leafpostlist.cc.

Referenced by LocalSubMatch::open_post_list().

◆ operator=()

void LeafPostList::operator= ( const LeafPostList & )

private

Don't allow assignment.

◆ recalc_maxweight()

double LeafPostList::recalc_maxweight ( )

virtual

Recalculate the upper bound on what get_weight() can return.

If the tree has pruned, get_maxweight() may use cached values. Calling this method instead forces a full recalculation.

Note that this method may be called after the postlist has reached the end. In this situation, the method should return 0.

Implements Xapian::PostingIterator::Internal.

Definition at line 89 of file leafpostlist.cc.

References get_maxweight().

◆ resolve_lazy_termweight()

double LeafPostList::resolve_lazy_termweight	(	Xapian::Weight *	weight_,
		Xapian::Weight::Internal *	stats,
		Xapian::termcount	qlen,
		Xapian::termcount	wqf,
		double	factor
	)

inline

Definition at line 73 of file leafpostlist.h.

References Assert, Xapian::Weight::get_maxpart(), Xapian::Weight::get_sumpart_needs_doclength_(), Xapian::Weight::init_(), and Xapian::Weight::Internal::termfreqs.

◆ set_term()

void LeafPostList::set_term ( const std::string & term_ )

inline

Set the term name.

This is useful when we optimise a term matching all documents to an all documents postlist under OP_SYNONYM, as the term name is used by LeafPostList::get_termfreq_est_using_stats() to locate the appropriate TermFreqs object.

Definition at line 139 of file leafpostlist.h.

Referenced by LocalSubMatch::open_post_list().

◆ set_termweight()

void LeafPostList::set_termweight ( const Xapian::Weight * weight_ )

Set the weighting scheme to use during matching.

If this isn't called, get_weight() and get_maxweight() will both return 0.

You should not call this more than once on a particular object.

Parameters

weight_ The weighting object to use. Must not be NULL.

Definition at line 57 of file leafpostlist.cc.

References Assert.

Referenced by LocalSubMatch::open_post_list().

Member Data Documentation

◆ need_doclength

bool LeafPostList::need_doclength

protected

Definition at line 49 of file leafpostlist.h.

◆ need_unique_terms

bool LeafPostList::need_unique_terms

protected

Definition at line 49 of file leafpostlist.h.

◆ term

std::string LeafPostList::term

protected

◆ weight

const Xapian::Weight* LeafPostList::weight

protected

Definition at line 47 of file leafpostlist.h.

The documentation for this class was generated from the following files:

api/leafpostlist.h
api/leafpostlist.cc

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ LeafPostList() [1/2]

◆ LeafPostList() [2/2]

◆ ~LeafPostList()

Member Function Documentation

◆ count_matching_subqs()

◆ gather_position_lists()

◆ get_maxweight()

◆ get_termfreq()

◆ get_termfreq_est()

◆ get_termfreq_est_using_stats()

◆ get_termfreq_max()

◆ get_termfreq_min()

◆ get_wdf_upper_bound()

◆ get_weight()

◆ open_nearby_postlist()

◆ operator=()

◆ recalc_maxweight()

◆ resolve_lazy_termweight()

◆ set_term()

◆ set_termweight()

Member Data Documentation

◆ need_doclength

◆ need_unique_terms

◆ term

◆ weight