1 /*
2 Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
3 Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
4 Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
5 Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
6
7 This library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Library General Public
9 License as published by the Free Software Foundation; either
10 version 2 of the License, or (at your option) any later version.
11
12 This library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Library General Public License for more details.
16
17 You should have received a copy of the GNU Library General Public License
18 along with this library; see the file COPYING.LIB. If not, write to
19 the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
20 Boston, MA 02110-1301, USA.
21 */
22
23 #include "config.h"
24 #include "core/fetch/MemoryCache.h"
25
26 #include "core/dom/CrossThreadTask.h"
27 #include "core/dom/Document.h"
28 #include "core/fetch/ResourcePtr.h"
29 #include "core/frame/FrameView.h"
30 #include "core/workers/WorkerGlobalScope.h"
31 #include "core/workers/WorkerLoaderProxy.h"
32 #include "core/workers/WorkerThread.h"
33 #include "platform/Logging.h"
34 #include "platform/TraceEvent.h"
35 #include "platform/weborigin/SecurityOrigin.h"
36 #include "platform/weborigin/SecurityOriginHash.h"
37 #include "public/platform/Platform.h"
38 #include "wtf/Assertions.h"
39 #include "wtf/CurrentTime.h"
40 #include "wtf/MathExtras.h"
41 #include "wtf/TemporaryChange.h"
42 #include "wtf/text/CString.h"
43
44 namespace WebCore {
45
46 static MemoryCache* gMemoryCache;
47
48 static const unsigned cDefaultCacheCapacity = 8192 * 1024;
49 static const unsigned cDeferredPruneDeadCapacityFactor = 2;
50 static const int cMinDelayBeforeLiveDecodedPrune = 1; // Seconds.
51 static const double cMaxPruneDeferralDelay = 0.5; // Seconds.
52 static const float cTargetPrunePercentage = .95f; // Percentage of capacity toward which we prune, to avoid immediately pruning again.
53
memoryCache()54 MemoryCache* memoryCache()
55 {
56 ASSERT(WTF::isMainThread());
57 if (!gMemoryCache)
58 gMemoryCache = new MemoryCache();
59 return gMemoryCache;
60 }
61
setMemoryCacheForTesting(MemoryCache * memoryCache)62 void setMemoryCacheForTesting(MemoryCache* memoryCache)
63 {
64 gMemoryCache = memoryCache;
65 }
66
MemoryCache()67 MemoryCache::MemoryCache()
68 : m_inPruneResources(false)
69 , m_prunePending(false)
70 , m_maxPruneDeferralDelay(cMaxPruneDeferralDelay)
71 , m_capacity(cDefaultCacheCapacity)
72 , m_minDeadCapacity(0)
73 , m_maxDeadCapacity(cDefaultCacheCapacity)
74 , m_maxDeferredPruneDeadCapacity(cDeferredPruneDeadCapacityFactor * cDefaultCacheCapacity)
75 , m_delayBeforeLiveDecodedPrune(cMinDelayBeforeLiveDecodedPrune)
76 , m_liveSize(0)
77 , m_deadSize(0)
78 #ifdef MEMORY_CACHE_STATS
79 , m_statsTimer(this, &MemoryCache::dumpStats)
80 #endif
81 {
82 #ifdef MEMORY_CACHE_STATS
83 const double statsIntervalInSeconds = 15;
84 m_statsTimer.startRepeating(statsIntervalInSeconds, FROM_HERE);
85 #endif
86 m_pruneTimeStamp = m_pruneFrameTimeStamp = FrameView::currentFrameTimeStamp();
87 }
88
~MemoryCache()89 MemoryCache::~MemoryCache()
90 {
91 if (m_prunePending)
92 blink::Platform::current()->currentThread()->removeTaskObserver(this);
93 }
94
removeFragmentIdentifierIfNeeded(const KURL & originalURL)95 KURL MemoryCache::removeFragmentIdentifierIfNeeded(const KURL& originalURL)
96 {
97 if (!originalURL.hasFragmentIdentifier())
98 return originalURL;
99 // Strip away fragment identifier from HTTP URLs.
100 // Data URLs must be unmodified. For file and custom URLs clients may expect resources
101 // to be unique even when they differ by the fragment identifier only.
102 if (!originalURL.protocolIsInHTTPFamily())
103 return originalURL;
104 KURL url = originalURL;
105 url.removeFragmentIdentifier();
106 return url;
107 }
108
add(Resource * resource)109 void MemoryCache::add(Resource* resource)
110 {
111 ASSERT(WTF::isMainThread());
112 RELEASE_ASSERT(!m_resources.contains(resource->url()));
113 m_resources.set(resource->url(), MemoryCacheEntry::create(resource));
114 update(resource, 0, resource->size(), true);
115
116 WTF_LOG(ResourceLoading, "MemoryCache::add Added '%s', resource %p\n", resource->url().string().latin1().data(), resource);
117 }
118
replace(Resource * newResource,Resource * oldResource)119 void MemoryCache::replace(Resource* newResource, Resource* oldResource)
120 {
121 if (MemoryCacheEntry* oldEntry = m_resources.get(oldResource->url()))
122 evict(oldEntry);
123 add(newResource);
124 if (newResource->decodedSize() && newResource->hasClients())
125 insertInLiveDecodedResourcesList(m_resources.get(newResource->url()));
126 }
127
remove(Resource * resource)128 void MemoryCache::remove(Resource* resource)
129 {
130 // The resource may have already been removed by someone other than our caller,
131 // who needed a fresh copy for a reload.
132 if (!contains(resource))
133 return;
134 evict(m_resources.get(resource->url()));
135 }
136
contains(const Resource * resource) const137 bool MemoryCache::contains(const Resource* resource) const
138 {
139 if (resource->url().isNull())
140 return false;
141 const MemoryCacheEntry* entry = m_resources.get(resource->url());
142 return entry && entry->m_resource == resource;
143 }
144
resourceForURL(const KURL & resourceURL)145 Resource* MemoryCache::resourceForURL(const KURL& resourceURL)
146 {
147 ASSERT(WTF::isMainThread());
148 KURL url = removeFragmentIdentifierIfNeeded(resourceURL);
149 MemoryCacheEntry* entry = m_resources.get(url);
150 if (!entry)
151 return 0;
152 Resource* resource = entry->m_resource.get();
153 if (resource && !resource->lock()) {
154 ASSERT(!resource->hasClients());
155 bool didEvict = evict(entry);
156 ASSERT_UNUSED(didEvict, didEvict);
157 return 0;
158 }
159 return resource;
160 }
161
deadCapacity() const162 size_t MemoryCache::deadCapacity() const
163 {
164 // Dead resource capacity is whatever space is not occupied by live resources, bounded by an independent minimum and maximum.
165 size_t capacity = m_capacity - std::min(m_liveSize, m_capacity); // Start with available capacity.
166 capacity = std::max(capacity, m_minDeadCapacity); // Make sure it's above the minimum.
167 capacity = std::min(capacity, m_maxDeadCapacity); // Make sure it's below the maximum.
168 return capacity;
169 }
170
liveCapacity() const171 size_t MemoryCache::liveCapacity() const
172 {
173 // Live resource capacity is whatever is left over after calculating dead resource capacity.
174 return m_capacity - deadCapacity();
175 }
176
pruneLiveResources()177 void MemoryCache::pruneLiveResources()
178 {
179 ASSERT(!m_prunePending);
180 size_t capacity = liveCapacity();
181 if (!m_liveSize || (capacity && m_liveSize <= capacity))
182 return;
183
184 size_t targetSize = static_cast<size_t>(capacity * cTargetPrunePercentage); // Cut by a percentage to avoid immediately pruning again.
185
186 // Destroy any decoded data in live objects that we can.
187 // Start from the tail, since this is the lowest priority
188 // and least recently accessed of the objects.
189
190 // The list might not be sorted by the m_lastDecodedFrameTimeStamp. The impact
191 // of this weaker invariant is minor as the below if statement to check the
192 // elapsedTime will evaluate to false as the current time will be a lot
193 // greater than the current->m_lastDecodedFrameTimeStamp.
194 // For more details see: https://bugs.webkit.org/show_bug.cgi?id=30209
195
196 // Start pruning from the lowest priority list.
197 for (int priority = MemoryCacheLiveResourcePriorityLow; priority <= MemoryCacheLiveResourcePriorityHigh; ++priority) {
198 MemoryCacheEntry* current = m_liveDecodedResources[priority].m_tail;
199 while (current) {
200 MemoryCacheEntry* previous = current->m_previousInLiveResourcesList;
201 ASSERT(current->m_resource->hasClients());
202 if (current->m_resource->isLoaded() && current->m_resource->decodedSize()) {
203 // Check to see if the remaining resources are too new to prune.
204 double elapsedTime = m_pruneFrameTimeStamp - current->m_lastDecodedAccessTime;
205 if (elapsedTime < m_delayBeforeLiveDecodedPrune)
206 return;
207
208 // Destroy our decoded data if possible. This will remove us
209 // from m_liveDecodedResources, and possibly move us to a
210 // different LRU list in m_allResources.
211 current->m_resource->prune();
212
213 if (targetSize && m_liveSize <= targetSize)
214 return;
215 }
216 current = previous;
217 }
218 }
219 }
220
pruneDeadResources()221 void MemoryCache::pruneDeadResources()
222 {
223 size_t capacity = deadCapacity();
224 if (!m_deadSize || (capacity && m_deadSize <= capacity))
225 return;
226
227 size_t targetSize = static_cast<size_t>(capacity * cTargetPrunePercentage); // Cut by a percentage to avoid immediately pruning again.
228
229 int size = m_allResources.size();
230
231 // See if we have any purged resources we can evict.
232 for (int i = 0; i < size; i++) {
233 MemoryCacheEntry* current = m_allResources[i].m_tail;
234 while (current) {
235 MemoryCacheEntry* previous = current->m_previousInAllResourcesList;
236 // Main Resources in the cache are only substitue data that was
237 // precached and should not be evicted.
238 if (current->m_resource->wasPurged() && current->m_resource->canDelete()
239 && current->m_resource->type() != Resource::MainResource) {
240 ASSERT(!current->m_resource->hasClients());
241 ASSERT(!current->m_resource->isPreloaded());
242 bool wasEvicted = evict(current);
243 ASSERT_UNUSED(wasEvicted, wasEvicted);
244 }
245 current = previous;
246 }
247 }
248 if (targetSize && m_deadSize <= targetSize)
249 return;
250
251 bool canShrinkLRULists = true;
252 for (int i = size - 1; i >= 0; i--) {
253 // Remove from the tail, since this is the least frequently accessed of the objects.
254 MemoryCacheEntry* current = m_allResources[i].m_tail;
255
256 // First flush all the decoded data in this queue.
257 while (current) {
258 // Protect 'previous' so it can't get deleted during destroyDecodedData().
259 MemoryCacheEntry* previous = current->m_previousInAllResourcesList;
260 ASSERT(!previous || contains(previous->m_resource.get()));
261 if (!current->m_resource->hasClients() && !current->m_resource->isPreloaded() && current->m_resource->isLoaded()) {
262 // Destroy our decoded data. This will remove us from
263 // m_liveDecodedResources, and possibly move us to a different
264 // LRU list in m_allResources.
265 current->m_resource->prune();
266
267 if (targetSize && m_deadSize <= targetSize)
268 return;
269 }
270 // Decoded data may reference other resources. Stop iterating if 'previous' somehow got
271 // kicked out of cache during destroyDecodedData().
272 if (previous && !contains(previous->m_resource.get()))
273 break;
274 current = previous;
275 }
276
277 // Now evict objects from this queue.
278 current = m_allResources[i].m_tail;
279 while (current) {
280 MemoryCacheEntry* previous = current->m_previousInAllResourcesList;
281 ASSERT(!previous || contains(previous->m_resource.get()));
282 if (!current->m_resource->hasClients() && !current->m_resource->isPreloaded()
283 && !current->m_resource->isCacheValidator() && current->m_resource->canDelete()
284 && current->m_resource->type() != Resource::MainResource) {
285 // Main Resources in the cache are only substitue data that was
286 // precached and should not be evicted.
287 bool wasEvicted = evict(current);
288 ASSERT_UNUSED(wasEvicted, wasEvicted);
289 if (targetSize && m_deadSize <= targetSize)
290 return;
291 }
292 if (previous && !contains(previous->m_resource.get()))
293 break;
294 current = previous;
295 }
296
297 // Shrink the vector back down so we don't waste time inspecting
298 // empty LRU lists on future prunes.
299 if (m_allResources[i].m_head)
300 canShrinkLRULists = false;
301 else if (canShrinkLRULists)
302 m_allResources.resize(i);
303 }
304 }
305
setCapacities(size_t minDeadBytes,size_t maxDeadBytes,size_t totalBytes)306 void MemoryCache::setCapacities(size_t minDeadBytes, size_t maxDeadBytes, size_t totalBytes)
307 {
308 ASSERT(minDeadBytes <= maxDeadBytes);
309 ASSERT(maxDeadBytes <= totalBytes);
310 m_minDeadCapacity = minDeadBytes;
311 m_maxDeadCapacity = maxDeadBytes;
312 m_maxDeferredPruneDeadCapacity = cDeferredPruneDeadCapacityFactor * maxDeadBytes;
313 m_capacity = totalBytes;
314 prune();
315 }
316
evict(MemoryCacheEntry * entry)317 bool MemoryCache::evict(MemoryCacheEntry* entry)
318 {
319 ASSERT(WTF::isMainThread());
320
321 Resource* resource = entry->m_resource.get();
322 bool canDelete = resource->canDelete();
323 WTF_LOG(ResourceLoading, "Evicting resource %p for '%s' from cache", resource, resource->url().string().latin1().data());
324 // The resource may have already been removed by someone other than our caller,
325 // who needed a fresh copy for a reload. See <http://bugs.webkit.org/show_bug.cgi?id=12479#c6>.
326 update(resource, resource->size(), 0, false);
327 removeFromLiveDecodedResourcesList(entry);
328
329 ResourceMap::iterator it = m_resources.find(resource->url());
330 ASSERT(it != m_resources.end());
331 OwnPtr<MemoryCacheEntry> entryPtr;
332 entryPtr.swap(it->value);
333 m_resources.remove(it);
334 return canDelete;
335 }
336
lruListFor(unsigned accessCount,size_t size)337 MemoryCache::LRUList* MemoryCache::lruListFor(unsigned accessCount, size_t size)
338 {
339 ASSERT(accessCount > 0);
340 unsigned queueIndex = WTF::fastLog2(size / accessCount);
341 if (m_allResources.size() <= queueIndex)
342 m_allResources.grow(queueIndex + 1);
343 return &m_allResources[queueIndex];
344 }
345
removeFromLRUList(MemoryCacheEntry * entry,LRUList * list)346 void MemoryCache::removeFromLRUList(MemoryCacheEntry* entry, LRUList* list)
347 {
348 #if ASSERT_ENABLED
349 // Verify that we are in fact in this list.
350 bool found = false;
351 for (MemoryCacheEntry* current = list->m_head; current; current = current->m_nextInAllResourcesList) {
352 if (current == entry) {
353 found = true;
354 break;
355 }
356 }
357 ASSERT(found);
358 #endif
359
360 MemoryCacheEntry* next = entry->m_nextInAllResourcesList;
361 MemoryCacheEntry* previous = entry->m_previousInAllResourcesList;
362 entry->m_nextInAllResourcesList = 0;
363 entry->m_previousInAllResourcesList = 0;
364
365 if (next)
366 next->m_previousInAllResourcesList = previous;
367 else
368 list->m_tail = previous;
369
370 if (previous)
371 previous->m_nextInAllResourcesList = next;
372 else
373 list->m_head = next;
374 }
375
insertInLRUList(MemoryCacheEntry * entry,LRUList * list)376 void MemoryCache::insertInLRUList(MemoryCacheEntry* entry, LRUList* list)
377 {
378 ASSERT(!entry->m_nextInAllResourcesList && !entry->m_previousInAllResourcesList);
379
380 entry->m_nextInAllResourcesList = list->m_head;
381 list->m_head = entry;
382
383 if (entry->m_nextInAllResourcesList)
384 entry->m_nextInAllResourcesList->m_previousInAllResourcesList = entry;
385 else
386 list->m_tail = entry;
387
388 #if ASSERT_ENABLED
389 // Verify that we are in now in the list like we should be.
390 bool found = false;
391 for (MemoryCacheEntry* current = list->m_head; current; current = current->m_nextInAllResourcesList) {
392 if (current == entry) {
393 found = true;
394 break;
395 }
396 }
397 ASSERT(found);
398 #endif
399 }
400
removeFromLiveDecodedResourcesList(MemoryCacheEntry * entry)401 void MemoryCache::removeFromLiveDecodedResourcesList(MemoryCacheEntry* entry)
402 {
403 // If we've never been accessed, then we're brand new and not in any list.
404 if (!entry->m_inLiveDecodedResourcesList)
405 return;
406 entry->m_inLiveDecodedResourcesList = false;
407
408 LRUList* list = &m_liveDecodedResources[entry->m_liveResourcePriority];
409
410 #if ASSERT_ENABLED
411 // Verify that we are in fact in this list.
412 bool found = false;
413 for (MemoryCacheEntry* current = list->m_head; current; current = current->m_nextInLiveResourcesList) {
414 if (current == entry) {
415 found = true;
416 break;
417 }
418 }
419 ASSERT(found);
420 #endif
421
422 MemoryCacheEntry* next = entry->m_nextInLiveResourcesList;
423 MemoryCacheEntry* previous = entry->m_previousInLiveResourcesList;
424
425 entry->m_nextInLiveResourcesList = 0;
426 entry->m_previousInLiveResourcesList = 0;
427
428 if (next)
429 next->m_previousInLiveResourcesList = previous;
430 else
431 list->m_tail = previous;
432
433 if (previous)
434 previous->m_nextInLiveResourcesList = next;
435 else
436 list->m_head = next;
437 }
438
insertInLiveDecodedResourcesList(MemoryCacheEntry * entry)439 void MemoryCache::insertInLiveDecodedResourcesList(MemoryCacheEntry* entry)
440 {
441 // Make sure we aren't in the list already.
442 ASSERT(!entry->m_nextInLiveResourcesList && !entry->m_previousInLiveResourcesList && !entry->m_inLiveDecodedResourcesList);
443 entry->m_inLiveDecodedResourcesList = true;
444
445 LRUList* list = &m_liveDecodedResources[entry->m_liveResourcePriority];
446 entry->m_nextInLiveResourcesList = list->m_head;
447 if (list->m_head)
448 list->m_head->m_previousInLiveResourcesList = entry;
449 list->m_head = entry;
450
451 if (!entry->m_nextInLiveResourcesList)
452 list->m_tail = entry;
453
454 #if ASSERT_ENABLED
455 // Verify that we are in now in the list like we should be.
456 bool found = false;
457 for (MemoryCacheEntry* current = list->m_head; current; current = current->m_nextInLiveResourcesList) {
458 if (current == entry) {
459 found = true;
460 break;
461 }
462 }
463 ASSERT(found);
464 #endif
465 }
466
makeLive(Resource * resource)467 void MemoryCache::makeLive(Resource* resource)
468 {
469 if (!contains(resource))
470 return;
471 ASSERT(m_deadSize >= resource->size());
472 m_liveSize += resource->size();
473 m_deadSize -= resource->size();
474 }
475
makeDead(Resource * resource)476 void MemoryCache::makeDead(Resource* resource)
477 {
478 if (!contains(resource))
479 return;
480 m_liveSize -= resource->size();
481 m_deadSize += resource->size();
482 removeFromLiveDecodedResourcesList(m_resources.get(resource->url()));
483 }
484
update(Resource * resource,size_t oldSize,size_t newSize,bool wasAccessed)485 void MemoryCache::update(Resource* resource, size_t oldSize, size_t newSize, bool wasAccessed)
486 {
487 if (!contains(resource))
488 return;
489 MemoryCacheEntry* entry = m_resources.get(resource->url());
490
491 // The object must now be moved to a different queue, since either its size or its accessCount has been changed,
492 // and both of those are used to determine which LRU queue the resource should be in.
493 if (oldSize)
494 removeFromLRUList(entry, lruListFor(entry->m_accessCount, oldSize));
495 if (wasAccessed)
496 entry->m_accessCount++;
497 if (newSize)
498 insertInLRUList(entry, lruListFor(entry->m_accessCount, newSize));
499
500 ptrdiff_t delta = newSize - oldSize;
501 if (resource->hasClients()) {
502 ASSERT(delta >= 0 || m_liveSize >= static_cast<size_t>(-delta) );
503 m_liveSize += delta;
504 } else {
505 ASSERT(delta >= 0 || m_deadSize >= static_cast<size_t>(-delta) );
506 m_deadSize += delta;
507 }
508 }
509
updateDecodedResource(Resource * resource,UpdateReason reason,MemoryCacheLiveResourcePriority priority)510 void MemoryCache::updateDecodedResource(Resource* resource, UpdateReason reason, MemoryCacheLiveResourcePriority priority)
511 {
512 if (!contains(resource))
513 return;
514 MemoryCacheEntry* entry = m_resources.get(resource->url());
515
516 removeFromLiveDecodedResourcesList(entry);
517 if (priority != MemoryCacheLiveResourcePriorityUnknown && priority != entry->m_liveResourcePriority)
518 entry->m_liveResourcePriority = priority;
519 if (resource->decodedSize() && resource->hasClients())
520 insertInLiveDecodedResourcesList(entry);
521
522 if (reason != UpdateForAccess)
523 return;
524
525 double timestamp = resource->isImage() ? FrameView::currentFrameTimeStamp() : 0.0;
526 if (!timestamp)
527 timestamp = currentTime();
528 entry->m_lastDecodedAccessTime = timestamp;
529 }
530
priority(Resource * resource) const531 MemoryCacheLiveResourcePriority MemoryCache::priority(Resource* resource) const
532 {
533 if (!contains(resource))
534 return MemoryCacheLiveResourcePriorityUnknown;
535 MemoryCacheEntry* entry = m_resources.get(resource->url());
536 return entry->m_liveResourcePriority;
537 }
538
removeURLFromCache(ExecutionContext * context,const KURL & url)539 void MemoryCache::removeURLFromCache(ExecutionContext* context, const KURL& url)
540 {
541 if (context->isWorkerGlobalScope()) {
542 WorkerGlobalScope* workerGlobalScope = toWorkerGlobalScope(context);
543 workerGlobalScope->thread()->workerLoaderProxy().postTaskToLoader(createCallbackTask(&removeURLFromCacheInternal, url));
544 return;
545 }
546 removeURLFromCacheInternal(context, url);
547 }
548
removeURLFromCacheInternal(ExecutionContext *,const KURL & url)549 void MemoryCache::removeURLFromCacheInternal(ExecutionContext*, const KURL& url)
550 {
551 if (Resource* resource = memoryCache()->resourceForURL(url))
552 memoryCache()->remove(resource);
553 }
554
addResource(Resource * o)555 void MemoryCache::TypeStatistic::addResource(Resource* o)
556 {
557 bool purged = o->wasPurged();
558 bool purgeable = o->isPurgeable() && !purged;
559 size_t pageSize = (o->encodedSize() + o->overheadSize() + 4095) & ~4095;
560 count++;
561 size += purged ? 0 : o->size();
562 liveSize += o->hasClients() ? o->size() : 0;
563 decodedSize += o->decodedSize();
564 encodedSize += o->encodedSize();
565 encodedSizeDuplicatedInDataURLs += o->url().protocolIsData() ? o->encodedSize() : 0;
566 purgeableSize += purgeable ? pageSize : 0;
567 purgedSize += purged ? pageSize : 0;
568 }
569
getStatistics()570 MemoryCache::Statistics MemoryCache::getStatistics()
571 {
572 Statistics stats;
573 ResourceMap::iterator e = m_resources.end();
574 for (ResourceMap::iterator i = m_resources.begin(); i != e; ++i) {
575 Resource* resource = i->value->m_resource.get();
576 switch (resource->type()) {
577 case Resource::Image:
578 stats.images.addResource(resource);
579 break;
580 case Resource::CSSStyleSheet:
581 stats.cssStyleSheets.addResource(resource);
582 break;
583 case Resource::Script:
584 stats.scripts.addResource(resource);
585 break;
586 case Resource::XSLStyleSheet:
587 stats.xslStyleSheets.addResource(resource);
588 break;
589 case Resource::Font:
590 stats.fonts.addResource(resource);
591 break;
592 default:
593 stats.other.addResource(resource);
594 break;
595 }
596 }
597 return stats;
598 }
599
evictResources()600 void MemoryCache::evictResources()
601 {
602 for (;;) {
603 ResourceMap::iterator i = m_resources.begin();
604 if (i == m_resources.end())
605 break;
606 evict(i->value.get());
607 }
608 }
609
prune(Resource * justReleasedResource)610 void MemoryCache::prune(Resource* justReleasedResource)
611 {
612 TRACE_EVENT0("renderer", "MemoryCache::prune()");
613
614 if (m_inPruneResources)
615 return;
616 if (m_liveSize + m_deadSize <= m_capacity && m_maxDeadCapacity && m_deadSize <= m_maxDeadCapacity) // Fast path.
617 return;
618
619 // To avoid burdening the current thread with repetitive pruning jobs,
620 // pruning is postponed until the end of the current task. If it has
621 // been more that m_maxPruneDeferralDelay since the last prune,
622 // then we prune immediately.
623 // If the current thread's run loop is not active, then pruning will happen
624 // immediately only if it has been over m_maxPruneDeferralDelay
625 // since the last prune.
626 double currentTime = WTF::currentTime();
627 if (m_prunePending) {
628 if (currentTime - m_pruneTimeStamp >= m_maxPruneDeferralDelay) {
629 pruneNow(currentTime);
630 }
631 } else {
632 if (currentTime - m_pruneTimeStamp >= m_maxPruneDeferralDelay) {
633 pruneNow(currentTime); // Delay exceeded, prune now.
634 } else {
635 // Defer.
636 blink::Platform::current()->currentThread()->addTaskObserver(this);
637 m_prunePending = true;
638 }
639 }
640
641 if (m_prunePending && m_deadSize > m_maxDeferredPruneDeadCapacity && justReleasedResource) {
642 // The following eviction does not respect LRU order, but it can be done
643 // immediately in constant time, as opposed to pruneDeadResources, which
644 // we would rather defer because it is O(N), which would make tear-down of N
645 // objects O(N^2) if we pruned immediately. This immediate eviction is a
646 // safeguard against runaway memory consumption by dead resources
647 // while a prune is pending.
648 // Main Resources in the cache are only substitue data that was
649 // precached and should not be evicted.
650 if (contains(justReleasedResource) && justReleasedResource->type() != Resource::MainResource)
651 evict(m_resources.get(justReleasedResource->url()));
652
653 // As a last resort, prune immediately
654 if (m_deadSize > m_maxDeferredPruneDeadCapacity)
655 pruneNow(currentTime);
656 }
657 }
658
willProcessTask()659 void MemoryCache::willProcessTask()
660 {
661 }
662
didProcessTask()663 void MemoryCache::didProcessTask()
664 {
665 // Perform deferred pruning
666 ASSERT(m_prunePending);
667 pruneNow(WTF::currentTime());
668 }
669
pruneNow(double currentTime)670 void MemoryCache::pruneNow(double currentTime)
671 {
672 if (m_prunePending) {
673 m_prunePending = false;
674 blink::Platform::current()->currentThread()->removeTaskObserver(this);
675 }
676
677 TemporaryChange<bool> reentrancyProtector(m_inPruneResources, true);
678 pruneDeadResources(); // Prune dead first, in case it was "borrowing" capacity from live.
679 pruneLiveResources();
680 m_pruneFrameTimeStamp = FrameView::currentFrameTimeStamp();
681 m_pruneTimeStamp = currentTime;
682 }
683
684 #ifdef MEMORY_CACHE_STATS
685
dumpStats(Timer<MemoryCache> *)686 void MemoryCache::dumpStats(Timer<MemoryCache>*)
687 {
688 Statistics s = getStatistics();
689 printf("%-13s %-13s %-13s %-13s %-13s %-13s %-13s\n", "", "Count", "Size", "LiveSize", "DecodedSize", "PurgeableSize", "PurgedSize");
690 printf("%-13s %-13s %-13s %-13s %-13s %-13s %-13s\n", "-------------", "-------------", "-------------", "-------------", "-------------", "-------------", "-------------");
691 printf("%-13s %13d %13d %13d %13d %13d %13d\n", "Images", s.images.count, s.images.size, s.images.liveSize, s.images.decodedSize, s.images.purgeableSize, s.images.purgedSize);
692 printf("%-13s %13d %13d %13d %13d %13d %13d\n", "CSS", s.cssStyleSheets.count, s.cssStyleSheets.size, s.cssStyleSheets.liveSize, s.cssStyleSheets.decodedSize, s.cssStyleSheets.purgeableSize, s.cssStyleSheets.purgedSize);
693 printf("%-13s %13d %13d %13d %13d %13d %13d\n", "XSL", s.xslStyleSheets.count, s.xslStyleSheets.size, s.xslStyleSheets.liveSize, s.xslStyleSheets.decodedSize, s.xslStyleSheets.purgeableSize, s.xslStyleSheets.purgedSize);
694 printf("%-13s %13d %13d %13d %13d %13d %13d\n", "JavaScript", s.scripts.count, s.scripts.size, s.scripts.liveSize, s.scripts.decodedSize, s.scripts.purgeableSize, s.scripts.purgedSize);
695 printf("%-13s %13d %13d %13d %13d %13d %13d\n", "Fonts", s.fonts.count, s.fonts.size, s.fonts.liveSize, s.fonts.decodedSize, s.fonts.purgeableSize, s.fonts.purgedSize);
696 printf("%-13s %13d %13d %13d %13d %13d %13d\n", "Other", s.other.count, s.other.size, s.other.liveSize, s.other.decodedSize, s.other.purgeableSize, s.other.purgedSize);
697 printf("%-13s %-13s %-13s %-13s %-13s %-13s %-13s\n\n", "-------------", "-------------", "-------------", "-------------", "-------------", "-------------", "-------------");
698
699 printf("Duplication of encoded data from data URLs\n");
700 printf("%-13s %13d of %13d\n", "Images", s.images.encodedSizeDuplicatedInDataURLs, s.images.encodedSize);
701 printf("%-13s %13d of %13d\n", "CSS", s.cssStyleSheets.encodedSizeDuplicatedInDataURLs, s.cssStyleSheets.encodedSize);
702 printf("%-13s %13d of %13d\n", "XSL", s.xslStyleSheets.encodedSizeDuplicatedInDataURLs, s.xslStyleSheets.encodedSize);
703 printf("%-13s %13d of %13d\n", "JavaScript", s.scripts.encodedSizeDuplicatedInDataURLs, s.scripts.encodedSize);
704 printf("%-13s %13d of %13d\n", "Fonts", s.fonts.encodedSizeDuplicatedInDataURLs, s.fonts.encodedSize);
705 printf("%-13s %13d of %13d\n", "Other", s.other.encodedSizeDuplicatedInDataURLs, s.other.encodedSize);
706 }
707
dumpLRULists(bool includeLive) const708 void MemoryCache::dumpLRULists(bool includeLive) const
709 {
710 printf("LRU-SP lists in eviction order (Kilobytes decoded, Kilobytes encoded, Access count, Referenced, isPurgeable, wasPurged):\n");
711
712 int size = m_allResources.size();
713 for (int i = size - 1; i >= 0; i--) {
714 printf("\n\nList %d: ", i);
715 Resource* current = m_allResources[i].m_tail;
716 while (current) {
717 Resource* prev = current->m_prevInAllResourcesList;
718 if (includeLive || !current->hasClients())
719 printf("(%.1fK, %.1fK, %uA, %dR, %d, %d); ", current->decodedSize() / 1024.0f, (current->encodedSize() + current->overheadSize()) / 1024.0f, current->accessCount(), current->hasClients(), current->isPurgeable(), current->wasPurged());
720
721 current = prev;
722 }
723 }
724 }
725
726 #endif // MEMORY_CACHE_STATS
727
728 } // namespace WebCore
729