private iterator to visit all resource cache entries

src/core/SkResourceCache.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkChecksum.h"
 #include "SkMessageBus.h"
 #include "SkMipMap.h"
@@ skipping 329 matching lines @@
 #ifdef SK_TRACK_PURGE_SHAREDID_HITRATE
     if (found) {
         gPurgeHitCounter += 1;
     }
 
     SkDebugf("PurgeShared calls=%d hits=%d rate=%g\n", gPurgeCallCounter, gPurgeHitCounter,
              gPurgeHitCounter * 100.0 / gPurgeCallCounter);
 #endif
 }
 
+void SkResourceCache::visitAll(Visitor visitor, void* context) {
+    // go backwards, just like purgeAsNeeded, just to make the code similar.
+    // could iterate either direction and still be correct.
+    Rec* rec = fTail;
+    while (rec) {
+        visitor(*rec, context);
+        rec = rec->fPrev;
+    }
+}
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
 size_t SkResourceCache::setTotalByteLimit(size_t newLimit) {
     size_t prevLimit = fTotalByteLimit;
     fTotalByteLimit = newLimit;
     if (newLimit < prevLimit) {
         this->purgeAsNeeded();
     }
     return prevLimit;
 }
 
 SkCachedData* SkResourceCache::newCachedData(size_t bytes) {
@@ skipping 241 matching lines @@
 bool SkResourceCache::Find(const Key& key, FindVisitor visitor, void* context) {
     SkAutoMutexAcquire am(gMutex);
     return get_cache()->find(key, visitor, context);
 }
 
 void SkResourceCache::Add(Rec* rec) {
     SkAutoMutexAcquire am(gMutex);
     get_cache()->add(rec);
 }
 
+void SkResourceCache::VisitAll(Visitor visitor, void* context) {
+    SkAutoMutexAcquire am(gMutex);
+    get_cache()->visitAll(visitor, context);
+}
+
 void SkResourceCache::PostPurgeSharedID(uint64_t sharedID) {
     if (sharedID) {
         SkMessageBus<PurgeSharedIDMessage>::Post(PurgeSharedIDMessage(sharedID));
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 #include "SkGraphics.h"
 #include "SkImageFilter.h"
@@ skipping 16 matching lines @@
 
 size_t SkGraphics::SetResourceCacheSingleAllocationByteLimit(size_t newLimit) {
     return SkResourceCache::SetSingleAllocationByteLimit(newLimit);
 }
 
 void SkGraphics::PurgeResourceCache() {
     SkImageFilter::PurgeCache();
     return SkResourceCache::PurgeAll();
 }
 
+/////////////
+
+static void dump_visitor(const SkResourceCache::Rec& rec, void*) {
+    SkDebugf("RC: %12s bytes %9lu  discardable %p\n",
+             rec.getCategory(), rec.bytesUsed(), rec.diagnostic_only_getDiscardable());
+}
+
+void SkResourceCache::TestDumpMemoryStatistics() {
+    VisitAll(dump_visitor, nullptr);
+}