org.eclipse.linuxtools.tmf.ui/src/org/eclipse/linuxtools/tmf/ui/viewers/events/TmfEventsCache.java

   1 /*******************************************************************************
   2  * Copyright (c) 2011 Ericsson
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Patrick Tasse - Initial API and implementation
  11  ******************************************************************************/
  12
  13 package org.eclipse.linuxtools.tmf.ui.viewers.events;
  14
  15 import java.util.ArrayList;
  16 import java.util.Arrays;
  17 import java.util.List;
  18
  19 import org.eclipse.core.runtime.IProgressMonitor;
  20 import org.eclipse.core.runtime.IStatus;
  21 import org.eclipse.core.runtime.Status;
  22 import org.eclipse.core.runtime.jobs.Job;
  23 import org.eclipse.linuxtools.internal.tmf.ui.Activator;
  24 import org.eclipse.linuxtools.tmf.core.component.ITmfDataProvider;
  25 import org.eclipse.linuxtools.tmf.core.event.ITmfEvent;
  26 import org.eclipse.linuxtools.tmf.core.filter.ITmfFilter;
  27 import org.eclipse.linuxtools.tmf.core.request.TmfDataRequest;
  28 import org.eclipse.linuxtools.tmf.core.trace.ITmfTrace;
  29
  30 /**
  31  * The generic TMF Events table events cache
  32  *
  33  * This can help avoid re-reading the trace when the user scrolls a window,
  34  * for example.
  35  *
  36  * @version 1.0
  37  * @author Patrick Tasse
  38  */
  39 public class TmfEventsCache {
  40
  41     /**
  42      * The generic TMF Events table cached event
  43      *
  44      * @version 1.0
  45      * @author Patrick Tasse
  46      */
  47     public static class CachedEvent {
  48         ITmfEvent event;
  49         long rank;
  50
  51         /**
  52          * Constructor for new cached events.
  53          *
  54          * @param iTmfEvent
  55          *            The original trace event
  56          * @param rank
  57          *            The rank of this event in the trace
  58          */
  59         public CachedEvent (ITmfEvent iTmfEvent, long rank) {
  60             this.event = iTmfEvent;
  61             this.rank = rank;
  62         }
  63     }
  64
  65     private final CachedEvent[] fCache;
  66     private int fCacheStartIndex = 0;
  67     private int fCacheEndIndex   = 0;
  68
  69     private ITmfTrace fTrace;
  70     private final TmfEventsTable fTable;
  71     private ITmfFilter fFilter;
  72     private final List<Integer> fFilterIndex = new ArrayList<Integer>(); // contains the event rank at each 'cache size' filtered events
  73
  74     /**
  75      * Constructor for the event cache
  76      *
  77      * @param cacheSize
  78      *            The size of the cache, in number of events
  79      * @param table
  80      *            The Events table this cache will cover
  81      */
  82     public TmfEventsCache(int cacheSize, TmfEventsTable table) {
  83         fCache = new CachedEvent[cacheSize];
  84         fTable = table;
  85     }
  86
  87     /**
  88      * Assign a new trace to this events cache. This clears the current
  89      * contents.
  90      *
  91      * @param trace
  92      *            The trace to assign.
  93      */
  94     public void setTrace(ITmfTrace trace) {
  95         fTrace = trace;
  96         clear();
  97     }
  98
  99     /**
 100      * Clear the current contents of this cache.
 101      */
 102     public synchronized void clear() {
 103         if (job != null && job.getState() != Job.NONE) {
 104             job.cancel();
 105         }
 106         Arrays.fill(fCache, null);
 107         fCacheStartIndex = 0;
 108         fCacheEndIndex = 0;
 109         fFilterIndex.clear();
 110     }
 111
 112     /**
 113      * Apply a filter on this event cache. This clears the current cache
 114      * contents.
 115      *
 116      * @param filter
 117      *            The ITmfFilter to apply.
 118      */
 119     public void applyFilter(ITmfFilter filter) {
 120         fFilter = filter;
 121         clear();
 122     }
 123
 124     /**
 125      * Clear the current filter on this cache. This also clears the current
 126      * cache contents.
 127      */
 128     public void clearFilter() {
 129         fFilter = null;
 130         clear();
 131     }
 132
 133     /**
 134      * Get an event from the cache. This will remove the event from the cache.
 135      *
 136      * FIXME this does not currently remove the event!
 137      *
 138      * @param index
 139      *            The index of this event in the cache
 140      * @return The cached event, or 'null' if there is no event at that index
 141      */
 142     public synchronized CachedEvent getEvent(int index) {
 143         if ((index >= fCacheStartIndex) && (index < fCacheEndIndex)) {
 144             int i = index - fCacheStartIndex;
 145             return fCache[i];
 146         }
 147         populateCache(index);
 148         return null;
 149     }
 150
 151     /**
 152      * Read an event, but without removing it from the cache.
 153      *
 154      * @param index
 155      *            Index of the event to peek
 156      * @return A reference to the event, or 'null' if there is no event at this
 157      *         index
 158      */
 159     public synchronized CachedEvent peekEvent(int index) {
 160         if ((index >= fCacheStartIndex) && (index < fCacheEndIndex)) {
 161             int i = index - fCacheStartIndex;
 162             return fCache[i];
 163         }
 164         return null;
 165     }
 166
 167     /**
 168      * Add a trace event to the cache.
 169      *
 170      * @param event
 171      *            The original trace event to be cached
 172      * @param rank
 173      *            The rank of this event in the trace
 174      * @param index
 175      *            The index this event will occupy in the cache
 176      */
 177     public synchronized void storeEvent(ITmfEvent event, long rank, int index) {
 178         if (index == fCacheEndIndex) {
 179             int i = index - fCacheStartIndex;
 180             if (i < fCache.length) {
 181                 fCache[i] = new CachedEvent(event.clone(), rank);
 182                 fCacheEndIndex++;
 183             }
 184         }
 185         if ((fFilter != null) && ((index % fCache.length) == 0)) {
 186             int i = index / fCache.length;
 187             fFilterIndex.add(i, Integer.valueOf((int) rank));
 188         }
 189     }
 190
 191     /**
 192      * Get the cache index of an event from his rank in the trace. This will
 193      * take in consideration any filter that might be applied.
 194      *
 195      * @param rank
 196      *            The rank of the event in the trace
 197      * @return The position (index) this event should use once cached
 198      */
 199     public int getFilteredEventIndex(final long rank) {
 200         int current;
 201         int startRank;
 202         TmfDataRequest request;
 203         final ITmfFilter filter = fFilter;
 204         synchronized (this) {
 205             int start = 0;
 206             int end = fFilterIndex.size();
 207
 208             if ((fCacheEndIndex - fCacheStartIndex) > 1) {
 209                 if (rank < fCache[0].rank) {
 210                     end = (fCacheStartIndex / fCache.length) + 1;
 211                 } else if (rank > fCache[fCacheEndIndex - fCacheStartIndex - 1].rank) {
 212                     start = fCacheEndIndex / fCache.length;
 213                 } else {
 214                     for (int i = 0; i < (fCacheEndIndex - fCacheStartIndex); i++) {
 215                         if (fCache[i].rank >= rank) {
 216                             return fCacheStartIndex + i;
 217                         }
 218                     }
 219                     return fCacheEndIndex;
 220                 }
 221             }
 222
 223             current = (start + end) / 2;
 224             while (current != start) {
 225                 if (rank < fFilterIndex.get(current)) {
 226                     end = current;
 227                     current = (start + end) / 2;
 228                 } else {
 229                     start = current;
 230                     current = (start + end) / 2;
 231                 }
 232             }
 233             startRank = fFilterIndex.size() > 0 ? fFilterIndex.get(current) : 0;
 234         }
 235
 236         final int index = current * fCache.length;
 237
 238         class DataRequest extends TmfDataRequest {
 239             ITmfFilter requestFilter;
 240             int requestRank;
 241             int requestIndex;
 242
 243             DataRequest(Class<? extends ITmfEvent> dataType, ITmfFilter reqFilter, int start, int nbRequested) {
 244                 super(dataType, start, nbRequested);
 245                 requestFilter = reqFilter;
 246                 requestRank = start;
 247                 requestIndex = index;
 248             }
 249
 250             @Override
 251             public void handleData(ITmfEvent event) {
 252                 super.handleData(event);
 253                 if (isCancelled()) {
 254                     return;
 255                 }
 256                 if (requestRank >= rank) {
 257                     cancel();
 258                     return;
 259                 }
 260                 requestRank++;
 261                 if (requestFilter.matches(event)) {
 262                     requestIndex++;
 263                 }
 264             }
 265
 266             public int getFilteredIndex() {
 267                 return requestIndex;
 268             }
 269         }
 270
 271         request = new DataRequest(ITmfEvent.class, filter, startRank, TmfDataRequest.ALL_DATA);
 272         ((ITmfDataProvider) fTrace).sendRequest(request);
 273         try {
 274             request.waitForCompletion();
 275             return ((DataRequest) request).getFilteredIndex();
 276         } catch (InterruptedException e) {
 277             Activator.getDefault().logError("Filter request interrupted!", e); //$NON-NLS-1$
 278         }
 279         return 0;
 280     }
 281
 282     // ------------------------------------------------------------------------
 283     // Event cache population
 284     // ------------------------------------------------------------------------
 285
 286     // The event fetching job
 287     private Job job;
 288     private synchronized void populateCache(final int index) {
 289
 290         /* Check if the current job will fetch the requested event:
 291          * 1. The job must exist
 292          * 2. It must be running (i.e. not completed)
 293          * 3. The requested index must be within the cache range
 294          *
 295          * If the job meets these conditions, we simply exit.
 296          * Otherwise, we create a new job but we might have to cancel
 297          * an existing job for an obsolete range.
 298          */
 299         if (job != null) {
 300             if (job.getState() != Job.NONE) {
 301                 if ((index >= fCacheStartIndex) && (index < (fCacheStartIndex + fCache.length))) {
 302                     return;
 303                 }
 304                 // The new index is out of the requested range
 305                 // Kill the job and start a new one
 306                 job.cancel();
 307             }
 308         }
 309
 310         fCacheStartIndex = index;
 311         fCacheEndIndex   = index;
 312
 313         job = new Job("Fetching Events") { //$NON-NLS-1$
 314             private int startIndex = index;
 315             private int skipCount = 0;
 316             @Override
 317             protected IStatus run(final IProgressMonitor monitor) {
 318
 319                 int nbRequested;
 320                 if (fFilter == null) {
 321                     nbRequested = fCache.length;
 322                 } else {
 323                     nbRequested = TmfDataRequest.ALL_DATA;
 324                     int i = index / fCache.length;
 325                     if (i < fFilterIndex.size()) {
 326                         startIndex = fFilterIndex.get(i);
 327                         skipCount = index - (i * fCache.length);
 328                     }
 329                 }
 330
 331                 TmfDataRequest request = new TmfDataRequest(ITmfEvent.class, startIndex, nbRequested) {
 332                     private int count = 0;
 333                     private long rank = startIndex;
 334                     @Override
 335                     public void handleData(ITmfEvent event) {
 336                         // If the job is canceled, cancel the request so waitForCompletion() will unlock
 337                         if (monitor.isCanceled()) {
 338                             cancel();
 339                             return;
 340                         }
 341                         super.handleData(event);
 342                         if (event != null) {
 343                             if (((fFilter == null) || fFilter.matches(event)) && (skipCount-- <= 0)) {
 344                                 synchronized (TmfEventsCache.this) {
 345                                     if (monitor.isCanceled()) {
 346                                         return;
 347                                     }
 348                                     fCache[count] = new CachedEvent(event.clone(), rank);
 349                                     count++;
 350                                     fCacheEndIndex++;
 351                                 }
 352                                 if (fFilter != null) {
 353                                     fTable.cacheUpdated(false);
 354                                 }
 355                             }
 356                         }
 357                         if (count >= fCache.length) {
 358                             cancel();
 359                         } else if ((fFilter != null) && (count >= (fTable.getTable().getItemCount() - 3))) { // -1 for header row, -2 for top and bottom filter status rows
 360                             cancel();
 361                         }
 362                         rank++;
 363                     }
 364                 };
 365
 366                 ((ITmfDataProvider) fTrace).sendRequest(request);
 367                 try {
 368                     request.waitForCompletion();
 369                 } catch (InterruptedException e) {
 370                     Activator.getDefault().logError("Wait for completion interrupted for populateCache ", e); //$NON-NLS-1$
 371                 }
 372
 373                 fTable.cacheUpdated(true);
 374
 375                 // Flag the UI thread that the cache is ready
 376                 if (monitor.isCanceled()) {
 377                     return Status.CANCEL_STATUS;
 378                 }
 379                 return Status.OK_STATUS;
 380             }
 381         };
 382         //job.setSystem(true);
 383         job.setPriority(Job.SHORT);
 384         job.schedule();
 385     }
 386
 387 }