xapian-core/api/postingiterator.cc

   1 /** @file postingiterator.cc
   2  *  @brief Class for iterating over a list of document ids.
   3  */
   4 /* Copyright (C) 2008,2009,2010,2011,2013 Olly Betts
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  19  */
  20
  21 #include <config.h>
  22
  23 #include "xapian/postingiterator.h"
  24
  25 #include "debuglog.h"
  26 #include "omassert.h"
  27 #include "postlist.h"
  28
  29 using namespace std;
  30
  31 namespace Xapian {
  32
  33 void
  34 PostingIterator::decref()
  35 {
  36     Assert(internal);
  37     if (--internal->_refs == 0)
  38         delete internal;
  39 }
  40
  41 void
  42 PostingIterator::post_advance(Internal * res)
  43 {
  44     if (res) {
  45         // FIXME: It seems this can't happen for any PostList which we wrap
  46         // with PostingIterator.
  47         ++res->_refs;
  48         decref();
  49         internal = res;
  50     }
  51     if (internal->at_end()) {
  52         decref();
  53         internal = NULL;
  54     }
  55 }
  56
  57 PostingIterator::PostingIterator(Internal *internal_) : internal(internal_)
  58 {
  59     LOGCALL_CTOR(API, "PostingIterator", internal_);
  60     if (!internal) return;
  61     try {
  62         ++internal->_refs;
  63         post_advance(internal->next());
  64     } catch (...) {
  65         // The destructor only runs if the constructor completes, so we have to
  66         // take care of cleaning up for ourselves here.
  67         decref();
  68         throw;
  69     }
  70 }
  71
  72 PostingIterator::PostingIterator(const PostingIterator & o)
  73     : internal(o.internal)
  74 {
  75     LOGCALL_CTOR(API, "PostingIterator", o);
  76     if (internal)
  77         ++internal->_refs;
  78 }
  79
  80 PostingIterator &
  81 PostingIterator::operator=(const PostingIterator & o)
  82 {
  83     LOGCALL(API, PostingIterator &, "PostingIterator::operator=", o);
  84     if (o.internal)
  85         ++o.internal->_refs;
  86     if (internal)
  87         decref();
  88     internal = o.internal;
  89     RETURN(*this);
  90 }
  91
  92 Xapian::docid
  93 PostingIterator::operator*() const
  94 {
  95     LOGCALL(API, Xapian::docid, "PostingIterator::operator*", NO_ARGS);
  96     Assert(internal);
  97     RETURN(internal->get_docid());
  98 }
  99
 100 PostingIterator &
 101 PostingIterator::operator++()
 102 {
 103     LOGCALL(API, PostingIterator &, "PostingIterator::operator++", NO_ARGS);
 104     Assert(internal);
 105     post_advance(internal->next());
 106     RETURN(*this);
 107 }
 108
 109 Xapian::termcount
 110 PostingIterator::get_wdf() const
 111 {
 112     LOGCALL(API, Xapian::termcount, "PostingIterator::get_wdf", NO_ARGS);
 113     Assert(internal);
 114     RETURN(internal->get_wdf());
 115 }
 116
 117 Xapian::termcount
 118 PostingIterator::get_doclength() const
 119 {
 120     LOGCALL(API, Xapian::termcount, "PostingIterator::get_doclength", NO_ARGS);
 121     Assert(internal);
 122     RETURN(internal->get_doclength());
 123 }
 124
 125 Xapian::termcount
 126 PostingIterator::get_unique_terms() const
 127 {
 128     LOGCALL(API, Xapian::termcount, "PostingIterator::get_unique_terms", NO_ARGS);
 129     Assert(internal);
 130     RETURN(internal->get_unique_terms());
 131 }
 132
 133 #if 0 // FIXME: TermIterator supports this, so PostingIterator really ought to.
 134 Xapian::termcount
 135 PostingIterator::positionlist_count() const
 136 {
 137     LOGCALL(API, Xapian::termcount, "PostingIterator::positionlist_count", NO_ARGS);
 138     Assert(internal);
 139     RETURN(internal->positionlist_count());
 140 }
 141 #endif
 142
 143 PositionIterator
 144 PostingIterator::positionlist_begin() const
 145 {
 146     LOGCALL(API, PositionIterator, "PostingIterator::positionlist_begin", NO_ARGS);
 147     Assert(internal);
 148     RETURN(PositionIterator(internal->open_position_list()));
 149 }
 150
 151 void
 152 PostingIterator::skip_to(Xapian::docid did)
 153 {
 154     LOGCALL_VOID(API, "PostingIterator::skip_to", did);
 155     if (internal)
 156         post_advance(internal->skip_to(did));
 157 }
 158
 159 std::string
 160 PostingIterator::get_description() const
 161 {
 162     string desc = "PostingIterator(";
 163     if (internal)
 164         desc += internal->get_description();
 165     desc += ')';
 166     return desc;
 167 }
 168
 169 }