PostList class implementing Query::OP_OR. More...

#include <orpostlist.h>

Inheritance diagram for OrPostList:

Collaboration diagram for OrPostList:

Public Member Functions
	OrPostList (PostList left, PostList right, PostListTree *pltree_)

	~OrPostList ()

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

double	get_weight (Xapian::termcount doclen, Xapian::termcount unique_terms, Xapian::termcount wdfdocmax) const
	Return the weight contribution for the current position. More...

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

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

void	get_docid_range (Xapian::docid &first, Xapian::docid &last) const
	Get the bounds on the range of docids this PostList can return. More...

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

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

Xapian::doccount	get_termfreq () const
	Get an estimate of the number of documents this PostList will return. 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...

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

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

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

	OrPostList (const OrPostList &)=delete
	Don't allow copying. More...

PostList *	decay_to_and (Xapian::docid did, double w_min, bool *valid_ptr=NULL)

PostList *	decay_to_andmaybe (PostList left, PostList right, Xapian::docid did, double w_min, bool *valid_ptr=NULL)

Private Attributes
PostList *	l
	Left side. More...

PostList *	r
	Right side. More...

Xapian::docid	l_did = 0

Xapian::docid	r_did = 0

double	l_max = 0

double	r_max = 0

PostListTree *	pltree

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

Protected Attributes inherited from Xapian::Internal::PostList
Xapian::doccount	termfreq
	Estimate of the number of documents this PostList will return. More...

Detailed Description

PostList class implementing Query::OP_OR.

Definition at line 29 of file orpostlist.h.

Constructor & Destructor Documentation

◆ OrPostList() [1/2]

OrPostList::OrPostList ( const OrPostList & )

privatedelete

Don't allow copying.

◆ OrPostList() [2/2]

OrPostList::OrPostList	(	PostList *	left,
		PostList *	right,
		PostListTree *	pltree_
	)

Definition at line 82 of file orpostlist.cc.

References estimate_or_assuming_indep(), Xapian::Internal::PostList::get_docid_range(), Xapian::Internal::PostList::get_termfreq(), l, r, and Xapian::Internal::PostList::termfreq.

◆ ~OrPostList()

OrPostList::~OrPostList ( )

inline

Definition at line 70 of file orpostlist.h.

References l, and r.

Member Function Documentation

◆ at_end()

bool OrPostList::at_end ( ) const

virtual

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

Implements Xapian::Internal::PostList.

Definition at line 419 of file orpostlist.cc.

◆ check()

PostList * OrPostList::check	(	Xapian::docid	did,
		double	w_min,
		bool &	valid
	)

virtual

Check if the specified docid occurs in this postlist.

The caller is required to ensure that the specified docid actually exists in the database.

This method acts like skip_to() if that can be done at little extra cost, in which case it then sets valid to true.

Otherwise it simply checks if a particular docid is present. If it is, valid is set to true. If it isn't, it sets valid to false, and leaves the position unspecified (and hence the result of calling methods which depend on the current position, such as get_docid() and at_end(), are also unspecified). In this state, next() will advance to the first matching position after docid, and skip_to() will act as it would if the position was the first matching position after docid. If valid is set to false, then NULL must be returned (pruning in this situation doesn't make sense).

The default implementation calls skip_to().

Reimplemented from Xapian::Internal::PostList.

Definition at line 336 of file orpostlist.cc.

References Assert, Xapian::Internal::PostList::at_end(), Xapian::Internal::PostList::check(), decay_to_and(), decay_to_andmaybe(), PostListTree::force_recalc(), Xapian::Internal::PostList::get_docid(), l, l_did, l_max, pltree, r, r_did, and r_max.

◆ count_matching_subqs()

Xapian::termcount OrPostList::count_matching_subqs ( ) const

virtual

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

Reimplemented from Xapian::Internal::PostList.

Definition at line 459 of file orpostlist.cc.

References Xapian::Internal::PostList::count_matching_subqs(), l, l_did, r, and r_did.

◆ decay_to_and()

PostList * OrPostList::decay_to_and	(	Xapian::docid	did,
		double	w_min,
		bool *	valid_ptr = `NULL`
	)

private

Definition at line 106 of file orpostlist.cc.

References Xapian::Internal::PostList::check(), PostListTree::force_recalc(), l, l_max, pltree, r, r_max, Xapian::Internal::PostList::skip_to(), and Xapian::Internal::PostList::termfreq.

Referenced by check(), next(), and skip_to().

◆ decay_to_andmaybe()

PostList * OrPostList::decay_to_andmaybe	(	PostList *	left,
		PostList *	right,
		Xapian::docid	did,
		double	w_min,
		bool *	valid_ptr = `NULL`
	)

private

Definition at line 127 of file orpostlist.cc.

References Xapian::Internal::PostList::check(), PostListTree::force_recalc(), l, l_max, pltree, r, r_max, and Xapian::Internal::PostList::skip_to().

Referenced by check(), next(), and skip_to().

◆ gather_position_lists()

void OrPostList::gather_position_lists ( OrPositionList * orposlist )

virtual

Gather PositionList* objects for a subtree.

Reimplemented from Xapian::Internal::PostList.

Definition at line 469 of file orpostlist.cc.

References Xapian::Internal::PostList::gather_position_lists(), l, l_did, r, and r_did.

◆ get_description()

std::string OrPostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::Internal::PostList.

Definition at line 438 of file orpostlist.cc.

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

◆ get_docid()

Xapian::docid OrPostList::get_docid ( ) const

virtual

Return the current docid.

Implements Xapian::Internal::PostList.

Definition at line 151 of file orpostlist.cc.

References l_did, min_non_zero(), and r_did.

◆ get_docid_range()

void OrPostList::get_docid_range	(	Xapian::docid &	first,
		Xapian::docid &	last
	)		const

virtual

Get the bounds on the range of docids this PostList can return.

Parameters

[out]	first	Set to a lower bound on the docids that can be returned, or not changed if there's no known lower bound (other than 1).
[out]	last	Set to an upper bound on the docids that can be returned, or not changed if there's no known upper bound (other than the highest used docid).

The default implementation (PostList::get_docid_range()) does nothing, which is suitable when there's no known lower or upper bound.

Reimplemented from Xapian::Internal::PostList.

Definition at line 428 of file orpostlist.cc.

References Xapian::Internal::PostList::get_docid_range(), l, and r.

◆ get_wdf()

Xapian::termcount OrPostList::get_wdf ( ) const

virtual

Return the wdf for the document at the current position.

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::Internal::PostList.

Definition at line 449 of file orpostlist.cc.

References Xapian::Internal::PostList::get_wdf(), l, l_did, r, and r_did.

◆ get_weight()

double OrPostList::get_weight	(	Xapian::termcount	doclen,
		Xapian::termcount	unique_terms,
		Xapian::termcount	wdfdocmax
	)		const

virtual

Return the weight contribution for the current position.

Implements Xapian::Internal::PostList.

Definition at line 159 of file orpostlist.cc.

References Xapian::Internal::PostList::get_weight(), l, l_did, r, and r_did.

◆ next()

PostList * OrPostList::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::Internal::PostList.

Definition at line 180 of file orpostlist.cc.

References Xapian::Internal::PostList::at_end(), decay_to_and(), decay_to_andmaybe(), PostListTree::force_recalc(), Xapian::Internal::PostList::get_docid(), l, l_did, l_max, Xapian::Internal::PostList::next(), pltree, r, r_did, and r_max.

◆ operator=()

void OrPostList::operator= ( const OrPostList & )

privatedelete

Don't allow assignment.

◆ recalc_maxweight()

double OrPostList::recalc_maxweight ( )

virtual

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

The maximum weight that get_weight() can return can decrease as the match progresses (typically when the PostList tree prunes) - calling this method calculates a current upper bound.

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

Implements Xapian::Internal::PostList.

Definition at line 172 of file orpostlist.cc.

References l, l_max, r, r_max, and Xapian::Internal::PostList::recalc_maxweight().

◆ skip_to()

PostList * OrPostList::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::Internal::PostList.

Definition at line 273 of file orpostlist.cc.

References Xapian::Internal::PostList::at_end(), decay_to_and(), decay_to_andmaybe(), PostListTree::force_recalc(), Xapian::Internal::PostList::get_docid(), l, l_did, l_max, pltree, r, r_did, r_max, and Xapian::Internal::PostList::skip_to().