xapian-core  1.4.19
Public Member Functions | Private Member Functions | Private Attributes | List of all members
ExternalPostList Class Reference

#include <externalpostlist.h>

+ Inheritance diagram for ExternalPostList:
+ Collaboration diagram for ExternalPostList:

Public Member Functions

 ExternalPostList (const Xapian::Database &db, Xapian::PostingSource *source_, double factor_, MultiMatch *matcher, Xapian::doccount shard_index)
 Constructor. 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...
 
Xapian::doccount get_termfreq_max () const
 Get an upper bound on the number of documents indexed by this term. More...
 
double get_maxweight () const
 Return an upper bound on what get_weight() can return. More...
 
Xapian::docid get_docid () const
 Return the current docid. More...
 
double get_weight () const
 Return the weight contribution for the current position. More...
 
Xapian::termcount get_doclength () const
 Return the length of current document. More...
 
Xapian::termcount get_unique_terms () const
 Return the number of unique terms in the current document. More...
 
double recalc_maxweight ()
 Recalculate the upper bound on what get_weight() can return. More...
 
PositionListread_position_list ()
 Read the position list for the term in the current document and return a pointer to it (owned by the PostList). More...
 
PostListnext (double w_min)
 Advance the current position to the next document in the postlist. More...
 
PostListskip_to (Xapian::docid, double w_min)
 Skip forward to the specified docid. More...
 
PostListcheck (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::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 TermFreqs get_termfreq_est_using_stats (const Xapian::Weight::Internal &stats) const
 Get an estimate for the termfreq and reltermfreq, given the stats. 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 PositionListopen_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...
 
Internalnext ()
 Advance the current position to the next document in the postlist. More...
 
Internalskip_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...
 
- Public Member Functions inherited from Xapian::Internal::intrusive_base
 intrusive_base ()
 Construct with no references. More...
 

Private Member Functions

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

Private Attributes

Xapian::Internal::opt_intrusive_ptr< Xapian::PostingSourcesource
 
Xapian::docid current
 
double factor
 

Additional Inherited Members

- Public Attributes inherited from Xapian::Internal::intrusive_base
unsigned _refs
 Reference count. More...
 
- Protected Member Functions inherited from Xapian::PostingIterator::Internal
 Internal ()
 Only constructable as a base class for derived classes. More...
 

Detailed Description

Definition at line 33 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_,
double  factor_,
MultiMatch matcher,
Xapian::doccount  shard_index 
)

Constructor.

Parameters
matcherThe matcher to notify when maximum weight changes.

Definition at line 34 of file externalpostlist.cc.

References Assert, Xapian::PostingSource::clone(), Xapian::PostingSource::init(), Xapian::PostingSource::register_matcher_(), Xapian::PostingSource::release(), and source.

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::PostingIterator::Internal.

Definition at line 184 of file externalpostlist.cc.

References Xapian::Internal::opt_intrusive_ptr< T >::get(), 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::PostingIterator::Internal.

Definition at line 165 of file externalpostlist.cc.

References Assert, Xapian::PostingSource::at_end(), Xapian::PostingSource::check(), current, Xapian::Internal::opt_intrusive_ptr< T >::get(), 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::PostingIterator::Internal.

Definition at line 191 of file externalpostlist.cc.

◆ get_description()

string ExternalPostList::get_description ( ) const
virtual

Return a string description of this object.

Implements Xapian::PostingIterator::Internal.

Definition at line 197 of file externalpostlist.cc.

References Xapian::Internal::opt_intrusive_ptr< T >::get(), Xapian::PostingSource::get_description(), and source.

◆ get_docid()

Xapian::docid ExternalPostList::get_docid ( ) const
virtual

Return the current docid.

Implements Xapian::PostingIterator::Internal.

Definition at line 90 of file externalpostlist.cc.

References Assert, current, LOGCALL, and RETURN.

◆ get_doclength()

Xapian::termcount ExternalPostList::get_doclength ( ) const
virtual

Return the length of current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 107 of file externalpostlist.cc.

References Assert.

◆ get_maxweight()

double ExternalPostList::get_maxweight ( ) const
virtual

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

Implements Xapian::PostingIterator::Internal.

Definition at line 80 of file externalpostlist.cc.

References factor, Xapian::Internal::opt_intrusive_ptr< T >::get(), Xapian::PostingSource::get_maxweight(), LOGCALL, RETURN, and source.

Referenced by recalc_maxweight().

◆ get_termfreq_est()

Xapian::doccount ExternalPostList::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 66 of file externalpostlist.cc.

References Assert, Xapian::Internal::opt_intrusive_ptr< T >::get(), Xapian::PostingSource::get_termfreq_est(), and source.

◆ get_termfreq_max()

Xapian::doccount ExternalPostList::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 73 of file externalpostlist.cc.

References Assert, Xapian::Internal::opt_intrusive_ptr< T >::get(), Xapian::PostingSource::get_termfreq_max(), and source.

◆ get_termfreq_min()

Xapian::doccount ExternalPostList::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 59 of file externalpostlist.cc.

References Assert, Xapian::Internal::opt_intrusive_ptr< T >::get(), Xapian::PostingSource::get_termfreq_min(), and source.

◆ get_unique_terms()

Xapian::termcount ExternalPostList::get_unique_terms ( ) const
virtual

Return the number of unique terms in the current document.

Implements Xapian::PostingIterator::Internal.

Definition at line 114 of file externalpostlist.cc.

References Assert.

◆ get_weight()

double ExternalPostList::get_weight ( ) const
virtual

Return the weight contribution for the current position.

Implements Xapian::PostingIterator::Internal.

Definition at line 98 of file externalpostlist.cc.

References Assert, factor, Xapian::Internal::opt_intrusive_ptr< T >::get(), 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_minThe 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 146 of file externalpostlist.cc.

References Assert, Xapian::Internal::opt_intrusive_ptr< T >::get(), 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::PostingIterator::Internal.

Definition at line 127 of file externalpostlist.cc.

◆ recalc_maxweight()

double ExternalPostList::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 121 of file externalpostlist.cc.

References get_maxweight().

◆ 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_minThe 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 155 of file externalpostlist.cc.

References Assert, current, Xapian::Internal::opt_intrusive_ptr< T >::get(), LOGCALL, RETURN, Xapian::PostingSource::skip_to(), source, and update_after_advance().

◆ update_after_advance()

PostList * ExternalPostList::update_after_advance ( )
private

Member Data Documentation

◆ current

Xapian::docid ExternalPostList::current
private

Definition at line 42 of file externalpostlist.h.

Referenced by check(), get_docid(), skip_to(), and update_after_advance().

◆ factor

double ExternalPostList::factor
private

Definition at line 44 of file externalpostlist.h.

Referenced by get_maxweight(), and get_weight().

◆ source


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