GrResourceCache.cpp revision 386319eebb806f62a60b16826750f364edc94ce5 
1
2/*
3 * Copyright 2010 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10
11#include "GrResourceCache.h"
12#include "GrResource.h"
13
14GrResourceEntry::GrResourceEntry(const GrResourceKey& key, GrResource* resource)
15        : fKey(key), fResource(resource) {
16    fLockCount = 0;
17    fPrev = fNext = NULL;
18
19    // we assume ownership of the resource, and will unref it when we die
20    GrAssert(resource);
21}
22
23GrResourceEntry::~GrResourceEntry() {
24    fResource->unref();
25}
26
27#if GR_DEBUG
28void GrResourceEntry::validate() const {
29    GrAssert(fLockCount >= 0);
30    GrAssert(fResource);
31    fResource->validate();
32}
33#endif
34
35///////////////////////////////////////////////////////////////////////////////
36
37GrResourceCache::GrResourceCache(int maxCount, size_t maxBytes) :
38        fMaxCount(maxCount),
39        fMaxBytes(maxBytes) {
40    fEntryCount          = 0;
41    fUnlockedEntryCount  = 0;
42    fEntryBytes          = 0;
43    fClientDetachedCount = 0;
44    fClientDetachedBytes = 0;
45
46    fHead = fTail = NULL;
47    fPurging = false;
48}
49
50GrResourceCache::~GrResourceCache() {
51    GrAutoResourceCacheValidate atcv(this);
52
53    this->removeAll();
54}
55
56void GrResourceCache::getLimits(int* maxResources, size_t* maxResourceBytes) const{
57    if (maxResources) {
58        *maxResources = fMaxCount;
59    }
60    if (maxResourceBytes) {
61        *maxResourceBytes = fMaxBytes;
62    }
63}
64
65void GrResourceCache::setLimits(int maxResources, size_t maxResourceBytes) {
66    bool smaller = (maxResources < fMaxCount) || (maxResourceBytes < fMaxBytes);
67
68    fMaxCount = maxResources;
69    fMaxBytes = maxResourceBytes;
70
71    if (smaller) {
72        this->purgeAsNeeded();
73    }
74}
75
76void GrResourceCache::internalDetach(GrResourceEntry* entry,
77                                    bool clientDetach) {
78    GrResourceEntry* prev = entry->fPrev;
79    GrResourceEntry* next = entry->fNext;
80
81    if (prev) {
82        prev->fNext = next;
83    } else {
84        fHead = next;
85    }
86    if (next) {
87        next->fPrev = prev;
88    } else {
89        fTail = prev;
90    }
91    if (!entry->isLocked()) {
92        --fUnlockedEntryCount;
93    }
94
95    entry->fPrev = NULL;
96    entry->fNext = NULL;
97
98    // update our stats
99    if (clientDetach) {
100        fClientDetachedCount += 1;
101        fClientDetachedBytes += entry->resource()->sizeInBytes();
102    } else {
103        fEntryCount -= 1;
104        fEntryBytes -= entry->resource()->sizeInBytes();
105    }
106}
107
108void GrResourceCache::attachToHead(GrResourceEntry* entry,
109                                  bool clientReattach) {
110    entry->fPrev = NULL;
111    entry->fNext = fHead;
112    if (fHead) {
113        fHead->fPrev = entry;
114    }
115    fHead = entry;
116    if (NULL == fTail) {
117        fTail = entry;
118    }
119    if (!entry->isLocked()) {
120        ++fUnlockedEntryCount;
121    }
122
123    // update our stats
124    if (clientReattach) {
125        fClientDetachedCount -= 1;
126        fClientDetachedBytes -= entry->resource()->sizeInBytes();
127    } else {
128        fEntryCount += 1;
129        fEntryBytes += entry->resource()->sizeInBytes();
130    }
131}
132
133class GrResourceCache::Key {
134    typedef GrResourceEntry T;
135
136    const GrResourceKey& fKey;
137public:
138    Key(const GrResourceKey& key) : fKey(key) {}
139
140    uint32_t getHash() const { return fKey.hashIndex(); }
141
142    static bool LT(const T& entry, const Key& key) {
143        return entry.key() < key.fKey;
144    }
145    static bool EQ(const T& entry, const Key& key) {
146        return entry.key() == key.fKey;
147    }
148#if GR_DEBUG
149    static uint32_t GetHash(const T& entry) {
150        return entry.key().hashIndex();
151    }
152    static bool LT(const T& a, const T& b) {
153        return a.key() < b.key();
154    }
155    static bool EQ(const T& a, const T& b) {
156        return a.key() == b.key();
157    }
158#endif
159};
160
161GrResourceEntry* GrResourceCache::findAndLock(const GrResourceKey& key,
162                                              LockType type) {
163    GrAutoResourceCacheValidate atcv(this);
164
165    GrResourceEntry* entry = fCache.find(key);
166    if (entry) {
167        this->internalDetach(entry, false);
168        // mark the entry as "busy" so it doesn't get purged
169        // do this between detach and attach for locked count tracking
170        if (kNested_LockType == type || !entry->isLocked()) {
171            entry->lock();
172        }
173        this->attachToHead(entry, false);
174    }
175    return entry;
176}
177
178bool GrResourceCache::hasKey(const GrResourceKey& key) const {
179    return NULL != fCache.find(key);
180}
181
182GrResourceEntry* GrResourceCache::create(const GrResourceKey& key,
183                                         GrResource* resource,
184                                         bool lock,
185                                         bool clientReattach) {
186    // we don't expect to create new resources during a purge. In theory
187    // this could cause purgeAsNeeded() into an infinite loop (e.g.
188    // each resource destroyed creates and locks 2 resources and
189    // unlocks 1 thereby causing a new purge).
190    GrAssert(!fPurging);
191    GrAutoResourceCacheValidate atcv(this);
192
193    GrResourceEntry* entry = new GrResourceEntry(key, resource);
194
195    if (lock) {
196        // mark the entry as "busy" so it doesn't get purged
197        // do this before attach for locked count tracking
198        entry->lock();
199    }
200
201    this->attachToHead(entry, clientReattach);
202    fCache.insert(key, entry);
203
204#if GR_DUMP_TEXTURE_UPLOAD
205    GrPrintf("--- add resource to cache %p, count=%d bytes= %d %d\n",
206             entry, fEntryCount, resource->sizeInBytes(), fEntryBytes);
207#endif
208
209    this->purgeAsNeeded();
210    return entry;
211}
212
213GrResourceEntry* GrResourceCache::createAndLock(const GrResourceKey& key,
214                                                GrResource* resource) {
215    return this->create(key, resource, true, false);
216}
217
218void GrResourceCache::attach(const GrResourceKey& key,
219                             GrResource* resource) {
220    this->create(key, resource, false, true);
221}
222
223void GrResourceCache::detach(GrResourceEntry* entry) {
224    GrAutoResourceCacheValidate atcv(this);
225    this->internalDetach(entry, true);
226    fCache.remove(entry->fKey, entry);
227}
228
229void GrResourceCache::freeEntry(GrResourceEntry* entry) {
230    GrAssert(NULL == entry->fNext && NULL == entry->fPrev);
231    delete entry;
232}
233
234void GrResourceCache::reattachAndUnlock(GrResourceEntry* entry) {
235    GrAutoResourceCacheValidate atcv(this);
236    if (entry->resource()->isValid()) {
237        attachToHead(entry, true);
238        fCache.insert(entry->key(), entry);
239    } else {
240        // If the resource went invalid while it was detached then purge it
241        // This can happen when a 3D context was lost,
242        // the client called GrContext::contextDestroyed() to notify Gr,
243        // and then later an SkGpuDevice's destructor releases its backing
244        // texture (which was invalidated at contextDestroyed time).
245        fClientDetachedCount -= 1;
246        fEntryCount -= 1;
247        size_t size = entry->resource()->sizeInBytes();
248        fClientDetachedBytes -= size;
249        fEntryBytes -= size;
250    }
251    this->unlock(entry);
252}
253
254void GrResourceCache::unlock(GrResourceEntry* entry) {
255    GrAutoResourceCacheValidate atcv(this);
256
257    GrAssert(entry);
258    GrAssert(entry->isLocked());
259    GrAssert(fCache.find(entry->key()));
260
261    entry->unlock();
262    if (!entry->isLocked()) {
263        ++fUnlockedEntryCount;
264    }
265    this->purgeAsNeeded();
266}
267
268/**
269 * Destroying a resource may potentially trigger the unlock of additional
270 * resources which in turn will trigger a nested purge. We block the nested
271 * purge using the fPurging variable. However, the initial purge will keep
272 * looping until either all resources in the cache are unlocked or we've met
273 * the budget. There is an assertion in createAndLock to check against a
274 * resource's destructor inserting new resources into the cache. If these
275 * new resources were unlocked before purgeAsNeeded completed it could
276 * potentially make purgeAsNeeded loop infinitely.
277 */
278void GrResourceCache::purgeAsNeeded() {
279    if (!fPurging) {
280        fPurging = true;
281        bool withinBudget = false;
282        do {
283            GrResourceEntry* entry = fTail;
284            while (entry && fUnlockedEntryCount) {
285                GrAutoResourceCacheValidate atcv(this);
286                if (fEntryCount <= fMaxCount && fEntryBytes <= fMaxBytes) {
287                    withinBudget = true;
288                    break;
289                }
290
291                GrResourceEntry* prev = entry->fPrev;
292                if (!entry->isLocked()) {
293                    // remove from our cache
294                    fCache.remove(entry->fKey, entry);
295
296                    // remove from our llist
297                    this->internalDetach(entry, false);
298
299        #if GR_DUMP_TEXTURE_UPLOAD
300                    GrPrintf("--- ~resource from cache %p [%d %d]\n",
301                             entry->resource(),
302                             entry->resource()->width(),
303                             entry->resource()->height());
304        #endif
305                    delete entry;
306                }
307                entry = prev;
308            }
309        } while (!withinBudget && fUnlockedEntryCount);
310        fPurging = false;
311    }
312}
313
314void GrResourceCache::removeAll() {
315    GrAutoResourceCacheValidate atcv(this);
316
317    // we can have one GrResource holding a lock on another
318    // so we don't want to just do a simple loop kicking each
319    // entry out. Instead change the budget and purge.
320
321    int savedMaxBytes = fMaxBytes;
322    int savedMaxCount = fMaxCount;
323    fMaxBytes = (size_t) -1;
324    fMaxCount = 0;
325    this->purgeAsNeeded();
326
327#if GR_DEBUG
328    GrAssert(!fUnlockedEntryCount);
329    if (!fCache.count()) {
330        // Items may have been detached from the cache (such as the backing
331        // texture for an SkGpuDevice). The above purge would not have removed
332        // them.
333        GrAssert(fEntryCount == fClientDetachedCount);
334        GrAssert(fEntryBytes == fClientDetachedBytes);
335        GrAssert(NULL == fHead);
336        GrAssert(NULL == fTail);
337    }
338#endif
339
340    fMaxBytes = savedMaxBytes;
341    fMaxCount = savedMaxCount;
342}
343
344///////////////////////////////////////////////////////////////////////////////
345
346#if GR_DEBUG
347static int countMatches(const GrResourceEntry* head, const GrResourceEntry* target) {
348    const GrResourceEntry* entry = head;
349    int count = 0;
350    while (entry) {
351        if (target == entry) {
352            count += 1;
353        }
354        entry = entry->next();
355    }
356    return count;
357}
358
359#if GR_DEBUG
360static bool both_zero_or_nonzero(int count, size_t bytes) {
361    return (count == 0 && bytes == 0) || (count > 0 && bytes > 0);
362}
363#endif
364
365void GrResourceCache::validate() const {
366    GrAssert(!fHead == !fTail);
367    GrAssert(both_zero_or_nonzero(fEntryCount, fEntryBytes));
368    GrAssert(both_zero_or_nonzero(fClientDetachedCount, fClientDetachedBytes));
369    GrAssert(fClientDetachedBytes <= fEntryBytes);
370    GrAssert(fClientDetachedCount <= fEntryCount);
371    GrAssert((fEntryCount - fClientDetachedCount) == fCache.count());
372
373    fCache.validate();
374
375    GrResourceEntry* entry = fHead;
376    int count = 0;
377    int unlockCount = 0;
378    size_t bytes = 0;
379    while (entry) {
380        entry->validate();
381        GrAssert(fCache.find(entry->key()));
382        count += 1;
383        bytes += entry->resource()->sizeInBytes();
384        if (!entry->isLocked()) {
385            unlockCount += 1;
386        }
387        entry = entry->fNext;
388    }
389    GrAssert(count == fEntryCount - fClientDetachedCount);
390    GrAssert(bytes == fEntryBytes  - fClientDetachedBytes);
391    GrAssert(unlockCount == fUnlockedEntryCount);
392
393    count = 0;
394    for (entry = fTail; entry; entry = entry->fPrev) {
395        count += 1;
396    }
397    GrAssert(count == fEntryCount - fClientDetachedCount);
398
399    for (int i = 0; i < count; i++) {
400        int matches = countMatches(fHead, fCache.getArray()[i]);
401        GrAssert(1 == matches);
402    }
403}
404#endif
405