BitmapFactory.cpp revision b644a3b84521e2155a5af985a4d4ed305474e567 
1#define LOG_TAG "BitmapFactory"
2
3#include "BitmapFactory.h"
4#include "NinePatchPeeker.h"
5#include "SkData.h"
6#include "SkFrontBufferedStream.h"
7#include "SkImageDecoder.h"
8#include "SkImageRef_ashmem.h"
9#include "SkImageRef_GlobalPool.h"
10#include "SkPixelRef.h"
11#include "SkStream.h"
12#include "SkTemplates.h"
13#include "SkUtils.h"
14#include "CreateJavaOutputStreamAdaptor.h"
15#include "AutoDecodeCancel.h"
16#include "Utils.h"
17#include "JNIHelp.h"
18#include "GraphicsJNI.h"
19
20#include <android_runtime/AndroidRuntime.h>
21#include <androidfw/Asset.h>
22#include <androidfw/ResourceTypes.h>
23#include <netinet/in.h>
24#include <stdio.h>
25#include <sys/mman.h>
26#include <sys/stat.h>
27
28jfieldID gOptions_justBoundsFieldID;
29jfieldID gOptions_sampleSizeFieldID;
30jfieldID gOptions_configFieldID;
31jfieldID gOptions_premultipliedFieldID;
32jfieldID gOptions_mutableFieldID;
33jfieldID gOptions_ditherFieldID;
34jfieldID gOptions_purgeableFieldID;
35jfieldID gOptions_shareableFieldID;
36jfieldID gOptions_preferQualityOverSpeedFieldID;
37jfieldID gOptions_scaledFieldID;
38jfieldID gOptions_densityFieldID;
39jfieldID gOptions_screenDensityFieldID;
40jfieldID gOptions_targetDensityFieldID;
41jfieldID gOptions_widthFieldID;
42jfieldID gOptions_heightFieldID;
43jfieldID gOptions_mimeFieldID;
44jfieldID gOptions_mCancelID;
45jfieldID gOptions_bitmapFieldID;
46jfieldID gBitmap_nativeBitmapFieldID;
47jfieldID gBitmap_layoutBoundsFieldID;
48
49#if 0
50    #define TRACE_BITMAP(code)  code
51#else
52    #define TRACE_BITMAP(code)
53#endif
54
55using namespace android;
56
57static inline int32_t validOrNeg1(bool isValid, int32_t value) {
58//    return isValid ? value : -1;
59    SkASSERT((int)isValid == 0 || (int)isValid == 1);
60    return ((int32_t)isValid - 1) | value;
61}
62
63jstring getMimeTypeString(JNIEnv* env, SkImageDecoder::Format format) {
64    static const struct {
65        SkImageDecoder::Format fFormat;
66        const char*            fMimeType;
67    } gMimeTypes[] = {
68        { SkImageDecoder::kBMP_Format,  "image/bmp" },
69        { SkImageDecoder::kGIF_Format,  "image/gif" },
70        { SkImageDecoder::kICO_Format,  "image/x-ico" },
71        { SkImageDecoder::kJPEG_Format, "image/jpeg" },
72        { SkImageDecoder::kPNG_Format,  "image/png" },
73        { SkImageDecoder::kWEBP_Format, "image/webp" },
74        { SkImageDecoder::kWBMP_Format, "image/vnd.wap.wbmp" }
75    };
76
77    const char* cstr = NULL;
78    for (size_t i = 0; i < SK_ARRAY_COUNT(gMimeTypes); i++) {
79        if (gMimeTypes[i].fFormat == format) {
80            cstr = gMimeTypes[i].fMimeType;
81            break;
82        }
83    }
84
85    jstring jstr = 0;
86    if (NULL != cstr) {
87        jstr = env->NewStringUTF(cstr);
88    }
89    return jstr;
90}
91
92static bool optionsPurgeable(JNIEnv* env, jobject options) {
93    return options != NULL && env->GetBooleanField(options, gOptions_purgeableFieldID);
94}
95
96static bool optionsShareable(JNIEnv* env, jobject options) {
97    return options != NULL && env->GetBooleanField(options, gOptions_shareableFieldID);
98}
99
100static bool optionsJustBounds(JNIEnv* env, jobject options) {
101    return options != NULL && env->GetBooleanField(options, gOptions_justBoundsFieldID);
102}
103
104static void scaleNinePatchChunk(android::Res_png_9patch* chunk, float scale) {
105    chunk->paddingLeft = int(chunk->paddingLeft * scale + 0.5f);
106    chunk->paddingTop = int(chunk->paddingTop * scale + 0.5f);
107    chunk->paddingRight = int(chunk->paddingRight * scale + 0.5f);
108    chunk->paddingBottom = int(chunk->paddingBottom * scale + 0.5f);
109
110    for (int i = 0; i < chunk->numXDivs; i++) {
111        chunk->xDivs[i] = int(chunk->xDivs[i] * scale + 0.5f);
112        if (i > 0 && chunk->xDivs[i] == chunk->xDivs[i - 1]) {
113            chunk->xDivs[i]++;
114        }
115    }
116
117    for (int i = 0; i < chunk->numYDivs; i++) {
118        chunk->yDivs[i] = int(chunk->yDivs[i] * scale + 0.5f);
119        if (i > 0 && chunk->yDivs[i] == chunk->yDivs[i - 1]) {
120            chunk->yDivs[i]++;
121        }
122    }
123}
124
125static SkPixelRef* installPixelRef(SkBitmap* bitmap, SkStreamRewindable* stream,
126        int sampleSize, bool ditherImage) {
127
128    SkImageInfo bitmapInfo;
129    if (!bitmap->asImageInfo(&bitmapInfo)) {
130        ALOGW("bitmap has unknown configuration so no memory has been allocated");
131        return NULL;
132    }
133
134    SkImageRef* pr;
135    // only use ashmem for large images, since mmaps come at a price
136    if (bitmap->getSize() >= 32 * 1024) {
137        pr = new SkImageRef_ashmem(bitmapInfo, stream, sampleSize);
138    } else {
139        pr = new SkImageRef_GlobalPool(bitmapInfo, stream, sampleSize);
140    }
141    pr->setDitherImage(ditherImage);
142    bitmap->setPixelRef(pr)->unref();
143    pr->isOpaque(bitmap);
144    return pr;
145}
146
147static SkBitmap::Config configForScaledOutput(SkBitmap::Config config) {
148    switch (config) {
149        case SkBitmap::kNo_Config:
150        case SkBitmap::kIndex8_Config:
151            return SkBitmap::kARGB_8888_Config;
152        default:
153            break;
154    }
155    return config;
156}
157
158class ScaleCheckingAllocator : public SkBitmap::HeapAllocator {
159public:
160    ScaleCheckingAllocator(float scale, int size)
161            : mScale(scale), mSize(size) {
162    }
163
164    virtual bool allocPixelRef(SkBitmap* bitmap, SkColorTable* ctable) {
165        // accounts for scale in final allocation, using eventual size and config
166        const int bytesPerPixel = SkBitmap::ComputeBytesPerPixel(
167                configForScaledOutput(bitmap->config()));
168        const int requestedSize = bytesPerPixel *
169                int(bitmap->width() * mScale + 0.5f) *
170                int(bitmap->height() * mScale + 0.5f);
171        if (requestedSize > mSize) {
172            ALOGW("bitmap for alloc reuse (%d bytes) can't fit scaled bitmap (%d bytes)",
173                    mSize, requestedSize);
174            return false;
175        }
176        return SkBitmap::HeapAllocator::allocPixelRef(bitmap, ctable);
177    }
178private:
179    const float mScale;
180    const int mSize;
181};
182
183class RecyclingPixelAllocator : public SkBitmap::Allocator {
184public:
185    RecyclingPixelAllocator(SkPixelRef* pixelRef, unsigned int size)
186            : mPixelRef(pixelRef), mSize(size) {
187        SkSafeRef(mPixelRef);
188    }
189
190    ~RecyclingPixelAllocator() {
191        SkSafeUnref(mPixelRef);
192    }
193
194    virtual bool allocPixelRef(SkBitmap* bitmap, SkColorTable* ctable) {
195        if (!bitmap->getSize64().is32() || bitmap->getSize() > mSize) {
196            ALOGW("bitmap marked for reuse (%d bytes) can't fit new bitmap (%d bytes)",
197                    mSize, bitmap->getSize());
198            return false;
199        }
200
201        SkImageInfo bitmapInfo;
202        if (!bitmap->asImageInfo(&bitmapInfo)) {
203            ALOGW("unable to reuse a bitmap as the target has an unknown bitmap configuration");
204            return false;
205        }
206
207        // Create a new pixelref with the new ctable that wraps the previous pixelref
208        SkPixelRef* pr = new AndroidPixelRef(*static_cast<AndroidPixelRef*>(mPixelRef),
209                bitmapInfo, bitmap->rowBytes(), ctable);
210
211        bitmap->setPixelRef(pr)->unref();
212        // since we're already allocated, we lockPixels right away
213        // HeapAllocator/JavaPixelAllocator behaves this way too
214        bitmap->lockPixels();
215        return true;
216    }
217
218private:
219    SkPixelRef* const mPixelRef;
220    const unsigned int mSize;
221};
222
223// since we "may" create a purgeable imageref, we require the stream be ref'able
224// i.e. dynamically allocated, since its lifetime may exceed the current stack
225// frame.
226static jobject doDecode(JNIEnv* env, SkStreamRewindable* stream, jobject padding,
227        jobject options, bool allowPurgeable, bool forcePurgeable = false) {
228
229    int sampleSize = 1;
230
231    SkImageDecoder::Mode mode = SkImageDecoder::kDecodePixels_Mode;
232    SkBitmap::Config prefConfig = SkBitmap::kARGB_8888_Config;
233
234    bool doDither = true;
235    bool isMutable = false;
236    float scale = 1.0f;
237    bool isPurgeable = forcePurgeable || (allowPurgeable && optionsPurgeable(env, options));
238    bool preferQualityOverSpeed = false;
239    bool requireUnpremultiplied = false;
240
241    jobject javaBitmap = NULL;
242
243    if (options != NULL) {
244        sampleSize = env->GetIntField(options, gOptions_sampleSizeFieldID);
245        if (optionsJustBounds(env, options)) {
246            mode = SkImageDecoder::kDecodeBounds_Mode;
247        }
248
249        // initialize these, in case we fail later on
250        env->SetIntField(options, gOptions_widthFieldID, -1);
251        env->SetIntField(options, gOptions_heightFieldID, -1);
252        env->SetObjectField(options, gOptions_mimeFieldID, 0);
253
254        jobject jconfig = env->GetObjectField(options, gOptions_configFieldID);
255        prefConfig = GraphicsJNI::getNativeBitmapConfig(env, jconfig);
256        isMutable = env->GetBooleanField(options, gOptions_mutableFieldID);
257        doDither = env->GetBooleanField(options, gOptions_ditherFieldID);
258        preferQualityOverSpeed = env->GetBooleanField(options,
259                gOptions_preferQualityOverSpeedFieldID);
260        requireUnpremultiplied = !env->GetBooleanField(options, gOptions_premultipliedFieldID);
261        javaBitmap = env->GetObjectField(options, gOptions_bitmapFieldID);
262
263        if (env->GetBooleanField(options, gOptions_scaledFieldID)) {
264            const int density = env->GetIntField(options, gOptions_densityFieldID);
265            const int targetDensity = env->GetIntField(options, gOptions_targetDensityFieldID);
266            const int screenDensity = env->GetIntField(options, gOptions_screenDensityFieldID);
267            if (density != 0 && targetDensity != 0 && density != screenDensity) {
268                scale = (float) targetDensity / density;
269            }
270        }
271    }
272
273    const bool willScale = scale != 1.0f;
274    isPurgeable &= !willScale;
275
276    SkImageDecoder* decoder = SkImageDecoder::Factory(stream);
277    if (decoder == NULL) {
278        return nullObjectReturn("SkImageDecoder::Factory returned null");
279    }
280
281    decoder->setSampleSize(sampleSize);
282    decoder->setDitherImage(doDither);
283    decoder->setPreferQualityOverSpeed(preferQualityOverSpeed);
284    decoder->setRequireUnpremultipliedColors(requireUnpremultiplied);
285
286    SkBitmap* outputBitmap = NULL;
287    unsigned int existingBufferSize = 0;
288    if (javaBitmap != NULL) {
289        outputBitmap = (SkBitmap*) env->GetLongField(javaBitmap, gBitmap_nativeBitmapFieldID);
290        if (outputBitmap->isImmutable()) {
291            ALOGW("Unable to reuse an immutable bitmap as an image decoder target.");
292            javaBitmap = NULL;
293            outputBitmap = NULL;
294        } else {
295            existingBufferSize = GraphicsJNI::getBitmapAllocationByteCount(env, javaBitmap);
296        }
297    }
298
299    SkAutoTDelete<SkBitmap> adb(outputBitmap == NULL ? new SkBitmap : NULL);
300    if (outputBitmap == NULL) outputBitmap = adb.get();
301
302    NinePatchPeeker peeker(decoder);
303    decoder->setPeeker(&peeker);
304
305    SkImageDecoder::Mode decodeMode = isPurgeable ? SkImageDecoder::kDecodeBounds_Mode : mode;
306
307    JavaPixelAllocator javaAllocator(env);
308    RecyclingPixelAllocator recyclingAllocator(outputBitmap->pixelRef(), existingBufferSize);
309    ScaleCheckingAllocator scaleCheckingAllocator(scale, existingBufferSize);
310    SkBitmap::Allocator* outputAllocator = (javaBitmap != NULL) ?
311            (SkBitmap::Allocator*)&recyclingAllocator : (SkBitmap::Allocator*)&javaAllocator;
312    if (decodeMode != SkImageDecoder::kDecodeBounds_Mode) {
313        if (!willScale) {
314            // If the java allocator is being used to allocate the pixel memory, the decoder
315            // need not write zeroes, since the memory is initialized to 0.
316            decoder->setSkipWritingZeroes(outputAllocator == &javaAllocator);
317            decoder->setAllocator(outputAllocator);
318        } else if (javaBitmap != NULL) {
319            // check for eventual scaled bounds at allocation time, so we don't decode the bitmap
320            // only to find the scaled result too large to fit in the allocation
321            decoder->setAllocator(&scaleCheckingAllocator);
322        }
323    }
324
325    // Only setup the decoder to be deleted after its stack-based, refcounted
326    // components (allocators, peekers, etc) are declared. This prevents RefCnt
327    // asserts from firing due to the order objects are deleted from the stack.
328    SkAutoTDelete<SkImageDecoder> add(decoder);
329
330    AutoDecoderCancel adc(options, decoder);
331
332    // To fix the race condition in case "requestCancelDecode"
333    // happens earlier than AutoDecoderCancel object is added
334    // to the gAutoDecoderCancelMutex linked list.
335    if (options != NULL && env->GetBooleanField(options, gOptions_mCancelID)) {
336        return nullObjectReturn("gOptions_mCancelID");
337    }
338
339    SkBitmap decodingBitmap;
340    if (!decoder->decode(stream, &decodingBitmap, prefConfig, decodeMode)) {
341        return nullObjectReturn("decoder->decode returned false");
342    }
343
344    int scaledWidth = decodingBitmap.width();
345    int scaledHeight = decodingBitmap.height();
346
347    if (willScale && mode != SkImageDecoder::kDecodeBounds_Mode) {
348        scaledWidth = int(scaledWidth * scale + 0.5f);
349        scaledHeight = int(scaledHeight * scale + 0.5f);
350    }
351
352    // update options (if any)
353    if (options != NULL) {
354        env->SetIntField(options, gOptions_widthFieldID, scaledWidth);
355        env->SetIntField(options, gOptions_heightFieldID, scaledHeight);
356        env->SetObjectField(options, gOptions_mimeFieldID,
357                getMimeTypeString(env, decoder->getFormat()));
358    }
359
360    // if we're in justBounds mode, return now (skip the java bitmap)
361    if (mode == SkImageDecoder::kDecodeBounds_Mode) {
362        return NULL;
363    }
364
365    jbyteArray ninePatchChunk = NULL;
366    if (peeker.fPatch != NULL) {
367        if (willScale) {
368            scaleNinePatchChunk(peeker.fPatch, scale);
369        }
370
371        size_t ninePatchArraySize = peeker.fPatch->serializedSize();
372        ninePatchChunk = env->NewByteArray(ninePatchArraySize);
373        if (ninePatchChunk == NULL) {
374            return nullObjectReturn("ninePatchChunk == null");
375        }
376
377        jbyte* array = (jbyte*) env->GetPrimitiveArrayCritical(ninePatchChunk, NULL);
378        if (array == NULL) {
379            return nullObjectReturn("primitive array == null");
380        }
381
382        peeker.fPatch->serialize(array);
383        env->ReleasePrimitiveArrayCritical(ninePatchChunk, array, 0);
384    }
385
386    jintArray layoutBounds = NULL;
387    if (peeker.fLayoutBounds != NULL) {
388        layoutBounds = env->NewIntArray(4);
389        if (layoutBounds == NULL) {
390            return nullObjectReturn("layoutBounds == null");
391        }
392
393        jint scaledBounds[4];
394        if (willScale) {
395            for (int i=0; i<4; i++) {
396                scaledBounds[i] = (jint)((((jint*)peeker.fLayoutBounds)[i]*scale) + .5f);
397            }
398        } else {
399            memcpy(scaledBounds, (jint*)peeker.fLayoutBounds, sizeof(scaledBounds));
400        }
401        env->SetIntArrayRegion(layoutBounds, 0, 4, scaledBounds);
402        if (javaBitmap != NULL) {
403            env->SetObjectField(javaBitmap, gBitmap_layoutBoundsFieldID, layoutBounds);
404        }
405    }
406
407    if (willScale) {
408        // This is weird so let me explain: we could use the scale parameter
409        // directly, but for historical reasons this is how the corresponding
410        // Dalvik code has always behaved. We simply recreate the behavior here.
411        // The result is slightly different from simply using scale because of
412        // the 0.5f rounding bias applied when computing the target image size
413        const float sx = scaledWidth / float(decodingBitmap.width());
414        const float sy = scaledHeight / float(decodingBitmap.height());
415
416        // TODO: avoid copying when scaled size equals decodingBitmap size
417        SkBitmap::Config config = configForScaledOutput(decodingBitmap.config());
418        // FIXME: If the alphaType is kUnpremul and the image has alpha, the
419        // colors may not be correct, since Skia does not yet support drawing
420        // to/from unpremultiplied bitmaps.
421        outputBitmap->setConfig(config, scaledWidth, scaledHeight, 0,
422                                decodingBitmap.alphaType());
423        if (!outputBitmap->allocPixels(outputAllocator, NULL)) {
424            return nullObjectReturn("allocation failed for scaled bitmap");
425        }
426
427        // If outputBitmap's pixels are newly allocated by Java, there is no need
428        // to erase to 0, since the pixels were initialized to 0.
429        if (outputAllocator != &javaAllocator) {
430            outputBitmap->eraseColor(0);
431        }
432
433        SkPaint paint;
434        paint.setFilterLevel(SkPaint::kLow_FilterLevel);
435
436        SkCanvas canvas(*outputBitmap);
437        canvas.scale(sx, sy);
438        canvas.drawBitmap(decodingBitmap, 0.0f, 0.0f, &paint);
439    } else {
440        outputBitmap->swap(decodingBitmap);
441    }
442
443    if (padding) {
444        if (peeker.fPatch != NULL) {
445            GraphicsJNI::set_jrect(env, padding,
446                    peeker.fPatch->paddingLeft, peeker.fPatch->paddingTop,
447                    peeker.fPatch->paddingRight, peeker.fPatch->paddingBottom);
448        } else {
449            GraphicsJNI::set_jrect(env, padding, -1, -1, -1, -1);
450        }
451    }
452
453    SkPixelRef* pr;
454    if (isPurgeable) {
455        pr = installPixelRef(outputBitmap, stream, sampleSize, doDither);
456    } else {
457        // if we get here, we're in kDecodePixels_Mode and will therefore
458        // already have a pixelref installed.
459        pr = outputBitmap->pixelRef();
460    }
461    if (pr == NULL) {
462        return nullObjectReturn("Got null SkPixelRef");
463    }
464
465    if (!isMutable && javaBitmap == NULL) {
466        // promise we will never change our pixels (great for sharing and pictures)
467        pr->setImmutable();
468    }
469
470    // detach bitmap from its autodeleter, since we want to own it now
471    adb.detach();
472
473    if (javaBitmap != NULL) {
474        bool isPremultiplied = !requireUnpremultiplied;
475        GraphicsJNI::reinitBitmap(env, javaBitmap, outputBitmap, isPremultiplied);
476        outputBitmap->notifyPixelsChanged();
477        // If a java bitmap was passed in for reuse, pass it back
478        return javaBitmap;
479    }
480
481    int bitmapCreateFlags = 0x0;
482    if (isMutable) bitmapCreateFlags |= GraphicsJNI::kBitmapCreateFlag_Mutable;
483    if (!requireUnpremultiplied) bitmapCreateFlags |= GraphicsJNI::kBitmapCreateFlag_Premultiplied;
484
485    // now create the java bitmap
486    return GraphicsJNI::createBitmap(env, outputBitmap, javaAllocator.getStorageObj(),
487            bitmapCreateFlags, ninePatchChunk, layoutBounds, -1);
488}
489
490// Need to buffer enough input to be able to rewind as much as might be read by a decoder
491// trying to determine the stream's format. Currently the most is 64, read by
492// SkImageDecoder_libwebp.
493// FIXME: Get this number from SkImageDecoder
494#define BYTES_TO_BUFFER 64
495
496static jobject nativeDecodeStream(JNIEnv* env, jobject clazz, jobject is, jbyteArray storage,
497        jobject padding, jobject options) {
498
499    jobject bitmap = NULL;
500    SkAutoTUnref<SkStream> stream(CreateJavaInputStreamAdaptor(env, is, storage));
501
502    if (stream.get()) {
503        SkAutoTUnref<SkStreamRewindable> bufferedStream(
504                SkFrontBufferedStream::Create(stream, BYTES_TO_BUFFER));
505        SkASSERT(bufferedStream.get() != NULL);
506        // for now we don't allow purgeable with java inputstreams
507        bitmap = doDecode(env, bufferedStream, padding, options, false, false);
508    }
509    return bitmap;
510}
511
512static jobject nativeDecodeFileDescriptor(JNIEnv* env, jobject clazz, jobject fileDescriptor,
513        jobject padding, jobject bitmapFactoryOptions) {
514
515    NPE_CHECK_RETURN_ZERO(env, fileDescriptor);
516
517    jint descriptor = jniGetFDFromFileDescriptor(env, fileDescriptor);
518
519    struct stat fdStat;
520    if (fstat(descriptor, &fdStat) == -1) {
521        doThrowIOE(env, "broken file descriptor");
522        return nullObjectReturn("fstat return -1");
523    }
524
525    // Restore the descriptor's offset on exiting this function.
526    AutoFDSeek autoRestore(descriptor);
527
528    FILE* file = fdopen(descriptor, "r");
529    if (file == NULL) {
530        return nullObjectReturn("Could not open file");
531    }
532
533    SkAutoTUnref<SkFILEStream> fileStream(new SkFILEStream(file,
534                         SkFILEStream::kCallerRetains_Ownership));
535
536    SkAutoTUnref<SkStreamRewindable> stream;
537
538    // Retain the old behavior of allowing purgeable if both purgeable and
539    // shareable are set to true.
540    bool isPurgeable = optionsPurgeable(env, bitmapFactoryOptions)
541                       && optionsShareable(env, bitmapFactoryOptions);
542    if (isPurgeable) {
543        // Copy the stream, so the image can be decoded multiple times without
544        // continuing to modify the original file descriptor.
545        // Copy beginning from the current position.
546        const size_t fileSize = fileStream->getLength() - fileStream->getPosition();
547        void* buffer = sk_malloc_flags(fileSize, 0);
548        if (buffer == NULL) {
549            return nullObjectReturn("Could not make a copy for ashmem");
550        }
551
552        SkAutoTUnref<SkData> data(SkData::NewFromMalloc(buffer, fileSize));
553
554        if (fileStream->read(buffer, fileSize) != fileSize) {
555            return nullObjectReturn("Could not read the file.");
556        }
557
558        stream.reset(new SkMemoryStream(data));
559    } else {
560        // Use a buffered stream. Although an SkFILEStream can be rewound, this
561        // ensures that SkImageDecoder::Factory never rewinds beyond the
562        // current position of the file descriptor.
563        stream.reset(SkFrontBufferedStream::Create(fileStream, BYTES_TO_BUFFER));
564    }
565
566    return doDecode(env, stream, padding, bitmapFactoryOptions, isPurgeable);
567}
568
569static jobject nativeDecodeAsset(JNIEnv* env, jobject clazz, jlong native_asset,
570        jobject padding, jobject options) {
571
572    SkStreamRewindable* stream;
573    Asset* asset = reinterpret_cast<Asset*>(native_asset);
574    bool forcePurgeable = optionsPurgeable(env, options);
575    if (forcePurgeable) {
576        // if we could "ref/reopen" the asset, we may not need to copy it here
577        // and we could assume optionsShareable, since assets are always RO
578        stream = CopyAssetToStream(asset);
579        if (stream == NULL) {
580            return NULL;
581        }
582    } else {
583        // since we know we'll be done with the asset when we return, we can
584        // just use a simple wrapper
585        stream = new AssetStreamAdaptor(asset,
586                                        AssetStreamAdaptor::kNo_OwnAsset,
587                                        AssetStreamAdaptor::kNo_HasMemoryBase);
588    }
589    SkAutoUnref aur(stream);
590    return doDecode(env, stream, padding, options, forcePurgeable, forcePurgeable);
591}
592
593static jobject nativeDecodeByteArray(JNIEnv* env, jobject, jbyteArray byteArray,
594        jint offset, jint length, jobject options) {
595
596    /*  If optionsShareable() we could decide to just wrap the java array and
597        share it, but that means adding a globalref to the java array object
598        and managing its lifetime. For now we just always copy the array's data
599        if optionsPurgeable(), unless we're just decoding bounds.
600     */
601    bool purgeable = optionsPurgeable(env, options) && !optionsJustBounds(env, options);
602    AutoJavaByteArray ar(env, byteArray);
603    SkMemoryStream* stream = new SkMemoryStream(ar.ptr() + offset, length, purgeable);
604    SkAutoUnref aur(stream);
605    return doDecode(env, stream, NULL, options, purgeable);
606}
607
608static void nativeRequestCancel(JNIEnv*, jobject joptions) {
609    (void)AutoDecoderCancel::RequestCancel(joptions);
610}
611
612static jboolean nativeIsSeekable(JNIEnv* env, jobject, jobject fileDescriptor) {
613    jint descriptor = jniGetFDFromFileDescriptor(env, fileDescriptor);
614    return ::lseek64(descriptor, 0, SEEK_CUR) != -1 ? JNI_TRUE : JNI_FALSE;
615}
616
617///////////////////////////////////////////////////////////////////////////////
618
619static JNINativeMethod gMethods[] = {
620    {   "nativeDecodeStream",
621        "(Ljava/io/InputStream;[BLandroid/graphics/Rect;Landroid/graphics/BitmapFactory$Options;)Landroid/graphics/Bitmap;",
622        (void*)nativeDecodeStream
623    },
624
625    {   "nativeDecodeFileDescriptor",
626        "(Ljava/io/FileDescriptor;Landroid/graphics/Rect;Landroid/graphics/BitmapFactory$Options;)Landroid/graphics/Bitmap;",
627        (void*)nativeDecodeFileDescriptor
628    },
629
630    {   "nativeDecodeAsset",
631        "(JLandroid/graphics/Rect;Landroid/graphics/BitmapFactory$Options;)Landroid/graphics/Bitmap;",
632        (void*)nativeDecodeAsset
633    },
634
635    {   "nativeDecodeByteArray",
636        "([BIILandroid/graphics/BitmapFactory$Options;)Landroid/graphics/Bitmap;",
637        (void*)nativeDecodeByteArray
638    },
639
640    {   "nativeIsSeekable",
641        "(Ljava/io/FileDescriptor;)Z",
642        (void*)nativeIsSeekable
643    },
644};
645
646static JNINativeMethod gOptionsMethods[] = {
647    {   "requestCancel", "()V", (void*)nativeRequestCancel }
648};
649
650static jfieldID getFieldIDCheck(JNIEnv* env, jclass clazz,
651                                const char fieldname[], const char type[]) {
652    jfieldID id = env->GetFieldID(clazz, fieldname, type);
653    SkASSERT(id);
654    return id;
655}
656
657int register_android_graphics_BitmapFactory(JNIEnv* env) {
658    jclass options_class = env->FindClass("android/graphics/BitmapFactory$Options");
659    SkASSERT(options_class);
660    gOptions_bitmapFieldID = getFieldIDCheck(env, options_class, "inBitmap",
661        "Landroid/graphics/Bitmap;");
662    gOptions_justBoundsFieldID = getFieldIDCheck(env, options_class, "inJustDecodeBounds", "Z");
663    gOptions_sampleSizeFieldID = getFieldIDCheck(env, options_class, "inSampleSize", "I");
664    gOptions_configFieldID = getFieldIDCheck(env, options_class, "inPreferredConfig",
665            "Landroid/graphics/Bitmap$Config;");
666    gOptions_premultipliedFieldID = getFieldIDCheck(env, options_class, "inPremultiplied", "Z");
667    gOptions_mutableFieldID = getFieldIDCheck(env, options_class, "inMutable", "Z");
668    gOptions_ditherFieldID = getFieldIDCheck(env, options_class, "inDither", "Z");
669    gOptions_purgeableFieldID = getFieldIDCheck(env, options_class, "inPurgeable", "Z");
670    gOptions_shareableFieldID = getFieldIDCheck(env, options_class, "inInputShareable", "Z");
671    gOptions_preferQualityOverSpeedFieldID = getFieldIDCheck(env, options_class,
672            "inPreferQualityOverSpeed", "Z");
673    gOptions_scaledFieldID = getFieldIDCheck(env, options_class, "inScaled", "Z");
674    gOptions_densityFieldID = getFieldIDCheck(env, options_class, "inDensity", "I");
675    gOptions_screenDensityFieldID = getFieldIDCheck(env, options_class, "inScreenDensity", "I");
676    gOptions_targetDensityFieldID = getFieldIDCheck(env, options_class, "inTargetDensity", "I");
677    gOptions_widthFieldID = getFieldIDCheck(env, options_class, "outWidth", "I");
678    gOptions_heightFieldID = getFieldIDCheck(env, options_class, "outHeight", "I");
679    gOptions_mimeFieldID = getFieldIDCheck(env, options_class, "outMimeType", "Ljava/lang/String;");
680    gOptions_mCancelID = getFieldIDCheck(env, options_class, "mCancel", "Z");
681
682    jclass bitmap_class = env->FindClass("android/graphics/Bitmap");
683    SkASSERT(bitmap_class);
684    gBitmap_nativeBitmapFieldID = getFieldIDCheck(env, bitmap_class, "mNativeBitmap", "J");
685    gBitmap_layoutBoundsFieldID = getFieldIDCheck(env, bitmap_class, "mLayoutBounds", "[I");
686    int ret = AndroidRuntime::registerNativeMethods(env,
687                                    "android/graphics/BitmapFactory$Options",
688                                    gOptionsMethods,
689                                    SK_ARRAY_COUNT(gOptionsMethods));
690    if (ret) {
691        return ret;
692    }
693    return android::AndroidRuntime::registerNativeMethods(env, "android/graphics/BitmapFactory",
694                                         gMethods, SK_ARRAY_COUNT(gMethods));
695}
696