workspace/plasma/runners/nepomuksearch/nepomuksearchrunner.cpp

   1 /* This file is part of the Nepomuk Project
   2    Copyright (c) 2008 Sebastian Trueg <trueg@kde.org>
   3
   4    This library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Library General Public
   6    License version 2 as published by the Free Software Foundation.
   7
   8    This library is distributed in the hope that it will be useful,
   9    but WITHOUT ANY WARRANTY; without even the implied warranty of
  10    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11    Library General Public License for more details.
  12
  13    You should have received a copy of the GNU Library General Public License
  14    along with this library; see the file COPYING.LIB.  If not, write to
  15    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  16    Boston, MA 02110-1301, USA.
  17 */
  18
  19 #include "nepomuksearchrunner.h"
  20 #include "queryclientwrapper.h"
  21
  22 #include "queryserviceclient.h"
  23
  24 #include <KRun>
  25 #include <KDebug>
  26 #include <KUrl>
  27
  28 #include <Nepomuk/Resource>
  29 #include <Nepomuk/ResourceManager>
  30
  31 #include <Soprano/Vocabulary/NAO>
  32
  33
  34 Q_DECLARE_METATYPE(Nepomuk::Resource)
  35
  36 namespace {
  37     /**
  38      * Milliseconds to wait before issuing the next query.
  39      * This timeout is intended to prevent us from starting
  40      * a query after each key press by the user. So it should
  41      * roughly equal the time between key presses of an average user.
  42      */
  43     const int s_userActionTimeout = 400;
  44 }
  45
  46
  47 Nepomuk::SearchRunner::SearchRunner( QObject* parent, const QVariantList& args )
  48     : Plasma::AbstractRunner( parent, args )
  49 {
  50     init();
  51 }
  52
  53
  54 Nepomuk::SearchRunner::SearchRunner( QObject* parent, const QString& serviceId )
  55     : Plasma::AbstractRunner( parent, serviceId )
  56 {
  57     init();
  58 }
  59
  60
  61 void Nepomuk::SearchRunner::init()
  62 {
  63     Nepomuk::ResourceManager::instance()->init();
  64
  65     // we are pretty slow at times and use DBus calls
  66     setSpeed( SlowSpeed );
  67
  68     // we are way less important than others, mostly because we are slow
  69     setPriority( LowPriority );
  70
  71     m_matchCnt = 0;
  72 }
  73
  74
  75 Nepomuk::SearchRunner::~SearchRunner()
  76 {
  77 }
  78
  79
  80 void Nepomuk::SearchRunner::match( Plasma::RunnerContext& context )
  81 {
  82     kDebug() << &context << context.query();
  83
  84     // This method needs to be thread-safe since KRunner does simply start new threads whenever
  85     // the query term changes.
  86     m_mutex.lock();
  87
  88     // we do not want to restart a query on each key-press. That would result
  89     // in way too many queries for the rather sluggy Nepomuk query service
  90     // Thus, we use a little timeout to make sure we do not query too often
  91
  92     // we remember the match count when starting to wait, so we do not start the query
  93     // in case another call deprecated us (KRunner will simply rerun this method in another
  94     // thread when the user input changes)
  95     int c = ++m_matchCnt;
  96
  97     kDebug() << &context << "waiting for match cnt" << c;
  98
  99     m_waiter.wait( &m_mutex, s_userActionTimeout );
 100     if( c != m_matchCnt ) {
 101         kDebug() << &context << "deprecated match cnt" << c;
 102         // we are no longer the latest call
 103         m_mutex.unlock();
 104         return;
 105     }
 106
 107     kDebug() << &context << "running match cnt" << c;
 108
 109     m_mutex.unlock();
 110
 111     // no queries on very short strings
 112     if( Search::QueryServiceClient::serviceAvailable() &&
 113         context.query().count() >= 3 ) {
 114         QueryClientWrapper queryWrapper( this, &context );
 115         queryWrapper.runQuery();
 116         m_waiter.wakeAll();
 117     }
 118 }
 119
 120
 121 void Nepomuk::SearchRunner::run( const Plasma::RunnerContext&, const Plasma::QueryMatch& match )
 122 {
 123     Nepomuk::Resource res = match.data().value<Nepomuk::Resource>();
 124     KUrl url;
 125
 126     if( res.hasType( Soprano::Vocabulary::NAO::Tag() ) ) {
 127         url.setProtocol( "nepomuksearch" );
 128         url.setPath( QString( "/hasTag:\"%1\"" ).arg( res.genericLabel() ) );
 129      }
 130     else {
 131         url = res.resourceUri();
 132     }
 133
 134     (void)new KRun( url, 0 );
 135 }
 136
 137 K_EXPORT_PLASMA_RUNNER(nepomuksearchrunner, Nepomuk::SearchRunner)
 138
 139 #include "nepomuksearchrunner.moc"