#include <externalpostlist.h>

Inheritance diagram for ExternalPostList:

Collaboration diagram for ExternalPostList:

Public Member Functions
	ExternalPostList (const Xapian::Database &db, Xapian::PostingSource source_, EstimateOp estimate_op, double factor_, bool *max_weight_cached_flag_ptr, Xapian::doccount shard_index)
	Constructor. More...

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...

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

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...

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

PostList *	skip_to (Xapian::docid, 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...

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

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

std::string	get_description () const
	Return a string description of this object. 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 Xapian::termcount	get_wdf () const
	Return the wdf for the document at the current position. 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...

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

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

Private Member Functions
	ExternalPostList (const ExternalPostList &)
	Disallow copying. More...

void	operator= (const ExternalPostList &)
	Disallow assignment. More...

PostList *	update_after_advance ()

Private Attributes
Xapian::Internal::opt_intrusive_ptr< Xapian::PostingSource >	source

Xapian::docid	current = 0

double	factor

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

Definition at line 34 of file externalpostlist.h.

Constructor & Destructor Documentation

◆ ExternalPostList() [1/2]

ExternalPostList::ExternalPostList ( const ExternalPostList & )

private

Disallow copying.

◆ ExternalPostList() [2/2]

ExternalPostList::ExternalPostList	(	const Xapian::Database &	db,
		Xapian::PostingSource *	source_,
		EstimateOp *	estimate_op,
		double	factor_,
		bool *	max_weight_cached_flag_ptr,
		Xapian::doccount	shard_index
	)

Constructor.

Parameters

estimate_op	Object to report min/est/max to.
max_weight_cached_flag_ptr	Pointer to flag to clear when max weight changes.

Definition at line 34 of file externalpostlist.cc.

References Assert, Xapian::PostingSource::clone(), Xapian::PostingSource::get_termfreq_est(), Xapian::PostingSource::get_termfreq_max(), Xapian::PostingSource::get_termfreq_min(), Xapian::PostingSource::release(), EstimateOp::report_termfreqs(), Xapian::PostingSource::reset(), Xapian::PostingSource::set_max_weight_cached_flag_ptr_(), source, and Xapian::Internal::PostList::termfreq.

Member Function Documentation

◆ at_end()

bool ExternalPostList::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 152 of file externalpostlist.cc.

References LOGCALL, RETURN, and source.

◆ check()

PostList * ExternalPostList::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 133 of file externalpostlist.cc.

References Assert, Xapian::PostingSource::at_end(), Xapian::PostingSource::check(), current, Xapian::PostingSource::get_docid(), LOGCALL, LOGLINE, RETURN, and source.

◆ count_matching_subqs()

Xapian::termcount ExternalPostList::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 159 of file externalpostlist.cc.

◆ get_description()

string ExternalPostList::get_description ( ) const

virtual

Return a string description of this object.

Implements Xapian::Internal::PostList.

Definition at line 165 of file externalpostlist.cc.

References Xapian::PostingSource::get_description(), and source.

◆ get_docid()

Xapian::docid ExternalPostList::get_docid ( ) const

virtual

Return the current docid.

Implements Xapian::Internal::PostList.

Definition at line 66 of file externalpostlist.cc.

References Assert, current, LOGCALL, and RETURN.

◆ get_weight()

double ExternalPostList::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 74 of file externalpostlist.cc.

References Assert, factor, Xapian::PostingSource::get_weight(), LOGCALL, RETURN, and source.

◆ next()

PostList * ExternalPostList::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 114 of file externalpostlist.cc.

References Assert, LOGCALL, Xapian::PostingSource::next(), RETURN, source, and update_after_advance().

◆ operator=()

void ExternalPostList::operator= ( const ExternalPostList & )

private

Disallow assignment.

◆ read_position_list()

PositionList * ExternalPostList::read_position_list ( )

virtual

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

The default implementation throws Xapian::UnimplementedError.

Reimplemented from Xapian::Internal::PostList.

Definition at line 95 of file externalpostlist.cc.

◆ recalc_maxweight()

double ExternalPostList::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 85 of file externalpostlist.cc.

References factor, Xapian::PostingSource::get_maxweight(), LOGCALL, RETURN, and source.

◆ skip_to()

PostList * ExternalPostList::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 123 of file externalpostlist.cc.

References Assert, current, LOGCALL, RETURN, Xapian::PostingSource::skip_to(), source, and update_after_advance().