Allow SkLazyPixelRef to use SkScaledImageCache

src/lazy/SkLazyPixelRef.cpp

Index: src/lazy/SkLazyPixelRef.cpp
diff --git a/src/lazy/SkLazyPixelRef.cpp b/src/lazy/SkLazyPixelRef.cpp
index 0454362b942f4e5ceb1aa5ece04270caa3e8f710..c1ad1a86cbea53b9c8ce69c32dc1ea9219a04ae3 100644
--- a/src/lazy/SkLazyPixelRef.cpp
+++ b/src/lazy/SkLazyPixelRef.cpp
@@ -11,6 +11,7 @@
 #include "SkData.h"
 #include "SkImageCache.h"
 #include "SkImagePriv.h"
+#include "SkScaledImageCache.h"
 
 #if LAZY_CACHE_STATS
 #include "SkThread.h"
@@ -22,11 +23,14 @@ int32_t SkLazyPixelRef::gCacheMisses;
 SkLazyPixelRef::SkLazyPixelRef(SkData* data, SkBitmapFactory::DecodeProc proc, SkImageCache* cache)
     // Pass NULL for the Mutex so that the default (ring buffer) will be used.
     : INHERITED(NULL)
+    , fErrorInDecoding(false)
     , fDecodeProc(proc)
     , fImageCache(cache)
-    , fCacheId(SkImageCache::UNINITIALIZED_ID)
-    , fRowBytes(0) {
+    , fCacheId(0)
+    , fRowBytes(0)
+    , fAllocator(NULL) {
     SkASSERT(fDecodeProc != NULL);
+    SkASSERT(0 == SkImageCache::UNINITIALIZED_ID);  // for fCacheId
     if (NULL == data) {
         fData = SkData::NewEmpty();
         fErrorInDecoding = true;
@@ -35,8 +39,9 @@ SkLazyPixelRef::SkLazyPixelRef(SkData* data, SkBitmapFactory::DecodeProc proc, S
         fData->ref();
         fErrorInDecoding = data->size() == 0;
     }
-    SkASSERT(cache != NULL);
-    cache->ref();
+    if (fImageCache != NULL) {
+        fImageCache->ref();
+    }
 
     // mark as uninitialized -- all fields are -1
     memset(&fLazilyCachedInfo, 0xFF, sizeof(fLazilyCachedInfo));
@@ -48,6 +53,14 @@ SkLazyPixelRef::SkLazyPixelRef(SkData* data, SkBitmapFactory::DecodeProc proc, S
 SkLazyPixelRef::~SkLazyPixelRef() {
     SkASSERT(fData != NULL);
     fData->unref();
+    SkSafeUnref(fAllocator);
+    if (NULL == fImageCache) {
+        if (fCacheId != 0) {
+            SkScaledImageCache::Unlock((SkScaledImageCache::ID *)(fCacheId));

[mtklein, 2013/10/24 17:03:25]

* affinity

+            // SkScaledImageCache needs a throwAwayCache(id) method.
+        }
+        return;
+    }
     SkASSERT(fImageCache);
     if (fCacheId != SkImageCache::UNINITIALIZED_ID) {
         fImageCache->throwAwayCache(fCacheId);
@@ -79,10 +92,89 @@ const SkImage::Info* SkLazyPixelRef::getCachedInfo() {
     return &fLazilyCachedInfo;
 }
 
+/**
+   Returns bitmap->getPixels() on success; NULL on failure */
+static void* decode_into_bitmap(SkImage::Info* info,
+                                 SkBitmapFactory::DecodeProc decodeProc,
+                                 size_t* rowBytes,
+                                 SkData* data,
+                                 SkBitmap::Allocator* allocator,
+                                 SkBitmap* bm) {
+    SkASSERT(info && decodeProc && rowBytes && data && bm);
+    if (!(bm->setConfig(SkImageInfoToBitmapConfig(*info), info->fWidth,
+                        info->fHeight, *rowBytes, info->fAlphaType)
+          && bm->allocPixels(allocator, NULL))) {
+        return NULL;
+    }
+    SkBitmapFactory::Target target;
+    target.fAddr = bm->getPixels();
+    target.fRowBytes = bm->rowBytes();
+    *rowBytes = target.fRowBytes;
+    if (!decodeProc(data->data(), data->size(), info, &target)) {
+        return NULL;
+    }
+    return target.fAddr;
+}
+
+void* SkLazyPixelRef::lockScaledImageCachePixels() {
+    SkASSERT(!fErrorInDecoding);
+    SkASSERT(NULL == fImageCache);
+    SkBitmap bitmap;
+    if (fLazilyCachedInfo.fWidth > 0) {  // fInfo already populated
+        fCacheId = (intptr_t)(SkScaledImageCache::FindAndLock(
+                                       this->getGenerationID(),
+                                       fLazilyCachedInfo.fWidth,
+                                       fLazilyCachedInfo.fHeight,
+                                       &bitmap));
+        if (fCacheId != 0) {
+            SkAutoLockPixels autoLockPixels(bitmap);
+            void* pixels = bitmap.getPixels();
+            SkASSERT(NULL != pixels);
+            // At this point, the autoLockPixels will unlockPixels()
+            // to remove bitmap's lock on the pixels.  We will then
+            // destroy bitmap.  The *only* guarantee that this pointer
+            // remains valid is the guarantee made by
+            // SkScaledImageCache that it will not destroy the *other*
+            // bitmap (SkScaledImageCache::Rec.fBitmap) that holds a
+            // reference to the concrete PixelRef while this record is
+            // locked.
+            return pixels;
+        }  // else cache has been purged, must re-decode.
+    } else {  // first time through this code, must populate info
+        (void)this->getCachedInfo();
+        if (fErrorInDecoding) {
+            return NULL;
+        }
+    }
+    SkASSERT(fLazilyCachedInfo.fWidth > 0);
+    void * ptr = decode_into_bitmap(&fLazilyCachedInfo, fDecodeProc,

[mtklein, 2013/10/24 17:03:25]

*

+                                    &fRowBytes, fData, fAllocator, &bitmap);
+    if (NULL == ptr) {
+        fErrorInDecoding = true;
+        return NULL;
+    }
+    fCacheId = (intptr_t)(SkScaledImageCache::AddAndLock(
+                                       this->getGenerationID(),
+                                       fLazilyCachedInfo.fWidth,
+                                       fLazilyCachedInfo.fHeight,
+                                       bitmap));
+    return ptr;
+}
+
 void* SkLazyPixelRef::onLockPixels(SkColorTable**) {
     if (fErrorInDecoding) {
         return NULL;
     }
+    if (NULL == fImageCache) {
+        return this->lockScaledImageCachePixels();
+    } else {
+        return this->lockImageCachePixels();
+    }
+}
+
+void* SkLazyPixelRef::lockImageCachePixels() {
+    SkASSERT(fImageCache != NULL);
+    SkASSERT(!fErrorInDecoding);
     SkBitmapFactory::Target target;
     // Check to see if the pixels still exist in the cache.
     if (SkImageCache::UNINITIALIZED_ID == fCacheId) {
@@ -144,10 +236,14 @@ void* SkLazyPixelRef::onLockPixels(SkColorTable**) {
 }
 
 void SkLazyPixelRef::onUnlockPixels() {
-    if (fErrorInDecoding) {
+    if (fErrorInDecoding || (0 == fCacheId)) {
         return;
     }
-    if (fCacheId != SkImageCache::UNINITIALIZED_ID) {
+    if (NULL == fImageCache) {
+        SkScaledImageCache::Unlock((SkScaledImageCache::ID *)(fCacheId));

[mtklein, 2013/10/24 17:03:25]

*

+        fCacheId = 0;
+        return;
+    } else {  // use fImageCache
         fImageCache->releaseCache(fCacheId);
     }
 }
@@ -157,8 +253,6 @@ SkData* SkLazyPixelRef::onRefEncodedData() {
     return fData;
 }
 
-#include "SkImagePriv.h"
-
 static bool init_from_info(SkBitmap* bm, const SkImage::Info& info,
                            size_t rowBytes) {
     SkBitmap::Config config = SkImageInfoToBitmapConfig(info);
@@ -206,3 +300,7 @@ bool SkLazyPixelRef::onDecodeInto(int pow2, SkBitmap* bitmap) {
     *bitmap = tmp;
     return true;
 }
+
+void SkLazyPixelRef::setAllocator(SkBitmap::Allocator * allocator) {

[mtklein, 2013/10/24 17:03:25]

*

+    SkRefCnt_SafeAssign(fAllocator, allocator);
+}