A postlist with weights modified by another postlist. More...

#include <andmaybepostlist.h>

Inheritance diagram for AndMaybePostList:

Collaboration diagram for AndMaybePostList:

Public Member Functions
Xapian::doccount	get_termfreq_max () const
	Get an upper bound on the number of documents indexed by this term. 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_est () const
	Get an estimate of the number of documents indexed by this term. 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::docid	get_docid () const
	Return the current docid. More...

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

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

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

PostList *	next (double w_min)
	Advance the current position to the next document in the postlist. More...

PostList *	skip_to (Xapian::docid did, double w_min)
	Skip forward to the specified docid. More...

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

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

virtual Xapian::termcount	get_doclength () const
	Return the document length of the document the current term comes from. More...

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

	AndMaybePostList (PostList left_, PostList right_, MultiMatch *matcher_, Xapian::doccount dbsize_)

	AndMaybePostList (PostList left_, PostList right_, MultiMatch *matcher_, Xapian::doccount dbsize_, Xapian::docid lhead_, Xapian::docid rhead_)
	Constructor for use by decomposing OrPostList. More...

PostList *	sync_rhs (double w_min)
	Synchronise the RHS to the LHS after construction. More...

Xapian::termcount	get_wdf () const
	get_wdf() for ANDMAYBE postlists returns the sum of the wdfs of the sub postlists which are at the current document - this is desirable when the ANDMAYBE is part of a synonym. 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...

Public Member Functions inherited from BranchPostList
	BranchPostList (PostList l_, PostList r_, MultiMatch *matcher_)

virtual	~BranchPostList ()

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 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 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 *	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...

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

Private Member Functions
PostList *	process_next_or_skip_to (double w_min, PostList *ret)

Private Attributes
Xapian::doccount	dbsize

Xapian::docid	lhead

Xapian::docid	rhead

double	lmax

double	rmax

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

Protected Member Functions inherited from BranchPostList
void	handle_prune (PostList &kid, PostList ret)
	Utility method, to call recalc_maxweight() and do the pruning if a next() or skip_to() returns non-NULL result. More...

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

Protected Attributes inherited from BranchPostList
PostList *	l
	Left sub-postlist. More...

PostList *	r
	Right sub-postlist. More...

MultiMatch *	matcher
	The object which is using this postlist to perform a match. More...

Detailed Description

A postlist with weights modified by another postlist.

This postlist returns a posting if and only if it is in the left sub-postlist.

If the posting does not occur in the right postlist, the weight for the posting is simply that in the left postlist. If the posting occurs in both postlists, the weight for the posting is the sum of the weights in the sub-postlists.

This type of postlist is useful for specifying a set of terms which must appear in the query result: these terms can be specified as the left hand argument, with the rest of the query being on the right hand side, and having the effect of modifying the weights.

The postlist is also used as a "decay product" of other postlist types during the match process: when a postlist can no longer cause a document to enter the mset on its own, but can influence relative rankings, it may be combined using one of these.

Definition at line 54 of file andmaybepostlist.h.

Constructor & Destructor Documentation

◆ AndMaybePostList() [1/2]

AndMaybePostList::AndMaybePostList	(	PostList *	left_,
		PostList *	right_,
		MultiMatch *	matcher_,
		Xapian::doccount	dbsize_
	)

inline

Definition at line 88 of file andmaybepostlist.h.

◆ AndMaybePostList() [2/2]

AndMaybePostList::AndMaybePostList	(	PostList *	left_,
		PostList *	right_,
		MultiMatch *	matcher_,
		Xapian::doccount	dbsize_,
		Xapian::docid	lhead_,
		Xapian::docid	rhead_
	)

inline

Constructor for use by decomposing OrPostList.

Definition at line 99 of file andmaybepostlist.h.

References count_matching_subqs(), gather_position_lists(), Xapian::PostingIterator::Internal::get_maxweight(), get_wdf(), BranchPostList::l, BranchPostList::r, and sync_rhs().

Member Function Documentation

◆ at_end()

bool AndMaybePostList::at_end ( ) const

virtual

Return true if the current position is past the last entry in this list.

Implements Xapian::PostingIterator::Internal.

Definition at line 186 of file andmaybepostlist.cc.

References lhead, LOGCALL, and RETURN.

◆ count_matching_subqs()

Xapian::termcount AndMaybePostList::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 226 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::count_matching_subqs(), BranchPostList::l, lhead, LOGCALL, BranchPostList::r, RETURN, and rhead.

Referenced by AndMaybePostList().

◆ gather_position_lists()

void AndMaybePostList::gather_position_lists ( OrPositionList * orposlist )

virtual

Gather PositionList* objects for a subtree.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 235 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::gather_position_lists(), BranchPostList::l, lhead, BranchPostList::r, and rhead.

Referenced by AndMaybePostList().

◆ get_description()

std::string AndMaybePostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 193 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::get_description(), BranchPostList::l, and BranchPostList::r.

◆ get_docid()

Xapian::docid AndMaybePostList::get_docid ( ) const

virtual

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 151 of file andmaybepostlist.cc.

References Assert, lhead, LOGCALL, and RETURN.

◆ get_doclength()

Xapian::termcount AndMaybePostList::get_doclength ( ) const

virtual

Return the document length of the document the current term comes from.

Implements Xapian::PostingIterator::Internal.

Definition at line 200 of file andmaybepostlist.cc.

References Assert, AssertEq, Xapian::PostingIterator::Internal::get_doclength(), BranchPostList::l, lhead, LOGCALL, BranchPostList::r, RETURN, and rhead.

◆ get_maxweight()

double AndMaybePostList::get_maxweight ( ) const

virtual

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

Implements Xapian::PostingIterator::Internal.

Definition at line 170 of file andmaybepostlist.cc.

References lmax, LOGCALL, RETURN, and rmax.

Referenced by recalc_maxweight().

◆ get_termfreq_est()

Xapian::doccount AndMaybePostList::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 134 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_est(), BranchPostList::l, LOGCALL, and RETURN.

◆ get_termfreq_est_using_stats()

TermFreqs AndMaybePostList::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 142 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_est_using_stats(), BranchPostList::l, LOGCALL, and RETURN.

◆ get_termfreq_max()

Xapian::doccount AndMaybePostList::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 118 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_max(), BranchPostList::l, LOGCALL, and RETURN.

◆ get_termfreq_min()

Xapian::doccount AndMaybePostList::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 126 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::get_termfreq_min(), BranchPostList::l, LOGCALL, and RETURN.

◆ get_unique_terms()

Xapian::termcount AndMaybePostList::get_unique_terms ( ) const

virtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 209 of file andmaybepostlist.cc.

References Assert, AssertEq, Xapian::PostingIterator::Internal::get_unique_terms(), BranchPostList::l, lhead, LOGCALL, BranchPostList::r, RETURN, and rhead.

◆ get_wdf()

Xapian::termcount AndMaybePostList::get_wdf ( ) const

virtual

get_wdf() for ANDMAYBE postlists returns the sum of the wdfs of the sub postlists which are at the current document - this is desirable when the ANDMAYBE is part of a synonym.

Reimplemented from Xapian::PostingIterator::Internal.

Definition at line 218 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::get_wdf(), BranchPostList::l, lhead, LOGCALL, BranchPostList::r, RETURN, and rhead.

Referenced by AndMaybePostList().

◆ get_weight()

double AndMaybePostList::get_weight ( ) const

virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 160 of file andmaybepostlist.cc.

References Assert, Xapian::PostingIterator::Internal::get_weight(), BranchPostList::l, lhead, LOGCALL, BranchPostList::r, RETURN, and rhead.

◆ next()

PostList * AndMaybePostList::next ( double w_min )

virtual

Advance the current position to the next document in the postlist.

The list starts before the first entry in the list, so next(), skip_to() or check() must be called before any methods which need the context of the current position.

Parameters

w_min The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::PostingIterator::Internal.

Definition at line 81 of file andmaybepostlist.cc.

References dbsize, BranchPostList::l, lhead, lmax, LOGCALL, LOGLINE, BranchPostList::matcher, Xapian::PostingIterator::Internal::next(), process_next_or_skip_to(), BranchPostList::r, RETURN, rhead, rmax, and skip_to_handling_prune().

◆ process_next_or_skip_to()

PostList * AndMaybePostList::process_next_or_skip_to	(	double	w_min,
		PostList *	ret
	)

private

Definition at line 33 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), check_handling_prune(), Xapian::PostingIterator::Internal::get_docid(), BranchPostList::handle_prune(), BranchPostList::l, lhead, lmax, LOGCALL, BranchPostList::matcher, BranchPostList::r, RETURN, and rhead.

Referenced by next(), and skip_to().

◆ recalc_maxweight()

double AndMaybePostList::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 177 of file andmaybepostlist.cc.

References get_maxweight(), BranchPostList::l, lmax, LOGCALL, BranchPostList::r, Xapian::PostingIterator::Internal::recalc_maxweight(), RETURN, and rmax.

◆ skip_to()

PostList * AndMaybePostList::skip_to	(	Xapian::docid	did,
		double	w_min
	)

virtual

Skip forward to the specified docid.

If the specified docid isn't in the list, position ourselves on the first document after it (or at_end() if no greater docids are present).

Parameters

w_min The minimum weight contribution that is needed (this is just a hint which PostList subclasses may ignore).

Returns: If a non-NULL pointer is returned, then the caller should substitute the returned pointer for its pointer to us, and then delete us. This "pruning" can only happen for a non-leaf subclass of this class.

Implements Xapian::PostingIterator::Internal.

Definition at line 97 of file andmaybepostlist.cc.

References dbsize, BranchPostList::l, lhead, lmax, LOGCALL, LOGLINE, BranchPostList::matcher, process_next_or_skip_to(), BranchPostList::r, RETURN, rhead, rmax, Xapian::PostingIterator::Internal::skip_to(), and skip_to_handling_prune().

◆ sync_rhs()

PostList * AndMaybePostList::sync_rhs ( double w_min )

Synchronise the RHS to the LHS after construction.

Used after constructing from a decomposing OrPostList

Definition at line 62 of file andmaybepostlist.cc.

References Xapian::PostingIterator::Internal::at_end(), check_handling_prune(), Xapian::PostingIterator::Internal::get_docid(), BranchPostList::l, lhead, lmax, LOGCALL, BranchPostList::matcher, BranchPostList::r, RETURN, and rhead.

Referenced by AndMaybePostList(), OrPostList::check(), OrPostList::next(), and OrPostList::skip_to().

Member Data Documentation

◆ dbsize

Xapian::doccount AndMaybePostList::dbsize

private

Definition at line 56 of file andmaybepostlist.h.

Referenced by next(), and skip_to().

◆ lhead

Xapian::docid AndMaybePostList::lhead

private

Definition at line 57 of file andmaybepostlist.h.

Referenced by at_end(), count_matching_subqs(), gather_position_lists(), get_docid(), get_doclength(), get_unique_terms(), get_wdf(), get_weight(), next(), process_next_or_skip_to(), skip_to(), and sync_rhs().

◆ lmax

double AndMaybePostList::lmax

private

Definition at line 58 of file andmaybepostlist.h.

Referenced by get_maxweight(), next(), process_next_or_skip_to(), recalc_maxweight(), skip_to(), and sync_rhs().

◆ rhead

Xapian::docid AndMaybePostList::rhead

private

Definition at line 57 of file andmaybepostlist.h.

Referenced by count_matching_subqs(), gather_position_lists(), get_doclength(), get_unique_terms(), get_wdf(), get_weight(), next(), process_next_or_skip_to(), skip_to(), and sync_rhs().

◆ rmax

double AndMaybePostList::rmax

private

Definition at line 58 of file andmaybepostlist.h.

Referenced by get_maxweight(), next(), recalc_maxweight(), and skip_to().

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

matcher/andmaybepostlist.h
matcher/andmaybepostlist.cc

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ AndMaybePostList() [1/2]

◆ AndMaybePostList() [2/2]

Member Function Documentation

◆ at_end()

◆ count_matching_subqs()

◆ gather_position_lists()

◆ get_description()

◆ get_docid()

◆ get_doclength()

◆ get_maxweight()

◆ get_termfreq_est()

◆ get_termfreq_est_using_stats()

◆ get_termfreq_max()

◆ get_termfreq_min()

◆ get_unique_terms()

◆ get_wdf()

◆ get_weight()

◆ next()

◆ process_next_or_skip_to()

◆ recalc_maxweight()

◆ skip_to()

◆ sync_rhs()

Member Data Documentation

◆ dbsize

◆ lhead

◆ lmax

◆ rhead

◆ rmax