Sketch DM refactor.

dm/DMSrcSink.cpp

Index: dm/DMSrcSink.cpp
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..4f272f11f877b493735b48c252f3449fe1b61d1e
--- /dev/null
+++ b/dm/DMSrcSink.cpp
@@ -0,0 +1,389 @@
+#include "DMSrcSink.h"
+#include "SamplePipeControllers.h"
+#include "SkCommonFlags.h"
+#include "SkDocument.h"
+#include "SkMultiPictureDraw.h"
+#include "SkOSFile.h"
+#include "SkPictureRecorder.h"
+#include "SkRandom.h"
+#include "SkTLS.h"
+
+namespace DM {
+
+void SafeUnref(SkPicture* p) { SkSafeUnref(p); }
+void SafeUnref(SkData*    d) { SkSafeUnref(d); }
+
+// FIXME: the GM objects themselves are not threadsafe, so we create and destroy them as needed.
+
+GMSrc::GMSrc(skiagm::GMRegistry::Factory factory) : fFactory(factory) {}
+
+Error GMSrc::draw(SkCanvas* canvas) const {
+    SkAutoTDelete<skiagm::GM> gm(fFactory(NULL));
+    canvas->concat(gm->getInitialTransform());
+    gm->draw(canvas);
+    return "";
+}
+
+SkISize GMSrc::size() const {
+    SkAutoTDelete<skiagm::GM> gm(fFactory(NULL));
+    return gm->getISize();
+}
+
+Name GMSrc::name() const {
+    SkAutoTDelete<skiagm::GM> gm(fFactory(NULL));
+    return gm->getName();
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+// The first call to draw() or size() will mmap the file to an SkData.  ~ImageSrc unrefs it.
+struct LazyLoadImage {
+    LazyLoadImage(const char* path) : path(path) {}
+    const char* path;
+
+    SkData* operator()() const { return SkData::NewFromFileName(path); }
+};
+
+ImageSrc::ImageSrc(SkString path, int subsets) : fPath(path), fSubsets(subsets) {}
+
+Error ImageSrc::draw(SkCanvas* canvas) const {
+    const SkData* encoded = fEncoded.get(LazyLoadImage(fPath.c_str()));
+    if (!encoded) {
+        return SkStringPrintf("Couldn't read %s.", fPath.c_str());
+    }
+    if (fSubsets == 0) {
+        // Decode the full image.
+        SkBitmap bitmap;
+        if (!SkImageDecoder::DecodeMemory(encoded->data(), encoded->size(), &bitmap)) {
+            return SkStringPrintf("Couldn't decode %s.", fPath.c_str());
+        }
+        canvas->drawBitmap(bitmap, 0,0);
+        return "";
+    }
+    // Decode random subsets.  This is a little involved.
+    SkMemoryStream stream(encoded->data(), encoded->size());
+    SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(&stream));
+    if (!decoder) {
+        return SkStringPrintf("Can't find a good decoder for %s.", fPath.c_str());
+    }
+    int w,h;
+    if (!decoder->buildTileIndex(&stream, &w, &h) || w*h == 1) {
+        return "";  // Not an error.  Subset decoding is not always supported.
+    }
+    SkRandom rand;
+    for (int i = 0; i < fSubsets; i++) {
+        SkIRect rect;
+        do {
+            rect.fLeft   = rand.nextULessThan(w);
+            rect.fTop    = rand.nextULessThan(h);
+            rect.fRight  = rand.nextULessThan(w);
+            rect.fBottom = rand.nextULessThan(h);
+            rect.sort();
+        } while (rect.isEmpty());
+        SkBitmap subset;
+        if (!decoder->decodeSubset(&subset, rect, kUnknown_SkColorType/*use best fit*/)) {
+            return SkStringPrintf("Could not decode subset %d.\n", i);
+        }
+        canvas->drawBitmap(subset, SkIntToScalar(rect.fLeft), SkIntToScalar(rect.fTop));
+    }
+    return "";
+}
+
+SkISize ImageSrc::size() const {
+    const SkData* encoded = fEncoded.get(LazyLoadImage(fPath.c_str()));
+    SkBitmap bitmap;
+    if (!encoded || !SkImageDecoder::DecodeMemory(encoded->data(),
+                                                  encoded->size(),
+                                                  &bitmap,
+                                                  kUnknown_SkColorType,
+                                                  SkImageDecoder::kDecodeBounds_Mode)) {
+        return SkISize::Make(0,0);
+    }
+    return bitmap.dimensions();
+}
+
+Name ImageSrc::name() const { return SkOSPath::Basename(fPath.c_str()); }
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+static const SkRect kSKPViewport = {0,0, 1000,1000};
+
+// The first call to draw() or size() will read the file into an SkPicture.  ~SKPSrc unrefs it.
+struct LazyLoadPicture {
+    LazyLoadPicture(const char* path) : path(path) {}
+    const char* path;
+
+    SkPicture* operator()() const {
+        SkAutoTUnref<SkStream> stream(SkStream::NewFromFile(path));
+        if (!stream) {
+            return NULL;
+        }
+        return SkPicture::CreateFromStream(stream);
+    }
+};
+
+SKPSrc::SKPSrc(SkString path) : fPath(path) {}
+
+Error SKPSrc::draw(SkCanvas* canvas) const {
+    const SkPicture* pic = fPic.get(LazyLoadPicture(fPath.c_str()));
+    if (!pic) {
+        return SkStringPrintf("Couldn't read %s.", fPath.c_str());
+    }
+    canvas->clipRect(kSKPViewport);
+    canvas->drawPicture(pic);
+    return "";
+}
+
+SkISize SKPSrc::size() const {
+    const SkPicture* pic = fPic.get(LazyLoadPicture(fPath.c_str()));
+    if (!pic) {
+        return SkISize::Make(0,0);
+    }
+    SkRect cull = pic->cullRect();
+    if (!cull.intersect(kSKPViewport)) {
+        sk_throw();
+    }
+    SkIRect bounds;
+    cull.roundOut(&bounds);
+    SkISize size = { bounds.width(), bounds.height() };
+    return size;
+}
+
+Name SKPSrc::name() const { return SkOSPath::Basename(fPath.c_str()); }
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+DEFINE_string(gpu_threading, "none",
+        "none:  single thread,\n"
+        "tls:   any thread, GrContextFactory in TLS   (crashy),\n"
+        "stack: any thread, GrContextFactory on stack (less crashy, differently so)");
+
+GPUSink::GPUSink(GrContextFactory::GLContextType ct, GrGLStandard api, int samples, bool dfText)
+    : fContextType(ct)
+    , fGpuAPI(api)
+    , fSampleCount(samples)
+    , fUseDFText(dfText) {}
+
+int GPUSink::enclave() const {
+    return FLAGS_gpu_threading.contains("none") ? kGPUSink_Enclave : kAnyThread_Enclave;
+}
+
+static void* CreateGrFactory()        { return new GrContextFactory; }
+static void  DeleteGrFactory(void* p) { delete (GrContextFactory*)p; }
+
+Error GPUSink::draw(const Src& src, SkBitmap* dst, SkWStream*) const {
+    GrContextFactory local, *factory = &local;
+    if (!FLAGS_gpu_threading.contains("stack")) {
+        factory = (GrContextFactory*)SkTLS::Get(CreateGrFactory, DeleteGrFactory);
+    }
+    // Does abandoning / resetting contexts make any sense if we have stack-scoped factories?
+    if (FLAGS_abandonGpuContext) {
+        factory->abandonContexts();
+    }
+    if (FLAGS_resetGpuContext || FLAGS_abandonGpuContext) {
+        factory->destroyContexts();
+    }
+    const SkISize size = src.size();
+    const SkImageInfo info =
+        SkImageInfo::Make(size.width(), size.height(), kN32_SkColorType, kPremul_SkAlphaType);
+    SkAutoTUnref<SkSurface> surface(
+            NewGpuSurface(factory, fContextType, fGpuAPI, info, fSampleCount, fUseDFText));
+    if (!surface) {
+        return "Could not create a surface.";
+    }
+    SkCanvas* canvas = surface->getCanvas();
+    Error err = src.draw(canvas);
+    if (!err.isEmpty()) {
+        return err;
+    }
+    canvas->flush();
+    dst->allocPixels(info);
+    canvas->readPixels(dst, 0,0);
+    return "";
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+PDFSink::PDFSink() {}
+
+Error PDFSink::draw(const Src& src, SkBitmap*, SkWStream* dst) const {
+    SkSize size;
+    size = src.size();
+    SkAutoTUnref<SkDocument> doc(SkDocument::CreatePDF(dst));
+    SkCanvas* canvas = doc->beginPage(size.width(), size.height());
+
+    Error err = src.draw(canvas);
+    if (!err.isEmpty()) {
+        return err;
+    }
+    canvas->flush();
+    doc->endPage();
+    doc->close();
+    return "";
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+RasterSink::RasterSink(SkColorType colorType) : fColorType(colorType) {}
+
+Error RasterSink::draw(const Src& src, SkBitmap* dst, SkWStream*) const {
+    const SkISize size = src.size();
+    // If there's an appropriate alpha type for this color type, use it, otherwise use premul.
+    SkAlphaType alphaType = kPremul_SkAlphaType;
+    (void)SkColorTypeValidateAlphaType(fColorType, alphaType, &alphaType);
+
+    dst->allocPixels(SkImageInfo::Make(size.width(), size.height(), fColorType, alphaType));
+    dst->eraseColor(SK_ColorTRANSPARENT);
+    SkCanvas canvas(*dst);
+    return src.draw(&canvas);
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+ViaMatrix::ViaMatrix(SkMatrix matrix, Sink* sink) : fMatrix(matrix), fSink(sink) {}
+
+Error ViaMatrix::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream) const {
+    // We turn our arguments into a Src, then draw that Src into our Sink to fill bitmap or stream.
+    struct ProxySrc : public Src {
+        const Src& fSrc;
+        SkMatrix fMatrix;
+        ProxySrc(const Src& src, SkMatrix matrix) : fSrc(src), fMatrix(matrix) {}
+
+        Error draw(SkCanvas* canvas) const SK_OVERRIDE {
+            canvas->concat(fMatrix);
+            return fSrc.draw(canvas);
+        }
+        SkISize size() const SK_OVERRIDE { return fSrc.size(); }
+        Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
+    } proxy(src, fMatrix);
+    return fSink->draw(proxy, bitmap, stream);
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+ViaPipe::ViaPipe(int flags, Sink* sink) : fFlags((SkGPipeWriter::Flags)flags), fSink(sink) {}
+
+Error ViaPipe::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream) const {
+    // We turn our arguments into a Src, then draw that Src into our Sink to fill bitmap or stream.
+    struct ProxySrc : public Src {
+        const Src& fSrc;
+        SkGPipeWriter::Flags fFlags;
+        ProxySrc(const Src& src, SkGPipeWriter::Flags flags) : fSrc(src), fFlags(flags) {}
+
+        Error draw(SkCanvas* canvas) const SK_OVERRIDE {
+            SkISize size = this->size();
+            // TODO: is DecodeMemory really required? Might help RAM usage to be lazy if we can.
+            PipeController controller(canvas, &SkImageDecoder::DecodeMemory);
+            SkGPipeWriter pipe;
+            return fSrc.draw(pipe.startRecording(&controller, fFlags, size.width(), size.height()));
+        }
+        SkISize size() const SK_OVERRIDE { return fSrc.size(); }
+        Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
+    } proxy(src, fFlags);
+    return fSink->draw(proxy, bitmap, stream);
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+ViaSerialization::ViaSerialization(Sink* sink) : fSink(sink) {}
+
+Error ViaSerialization::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream) const {
+    // Record our Src into a picture.
+    SkSize size;
+    size = src.size();
+    SkPictureRecorder recorder;
+    Error err = src.draw(recorder.beginRecording(size.width(), size.height()));
+    if (!err.isEmpty()) {
+        return err;
+    }
+    SkAutoTUnref<SkPicture> pic(recorder.endRecording());
+
+    // Serialize it and then deserialize it.
+    SkDynamicMemoryWStream wStream;
+    pic->serialize(&wStream);
+    SkAutoTUnref<SkStream> rStream(wStream.detachAsStream());
+    SkAutoTUnref<SkPicture> deserialized(SkPicture::CreateFromStream(rStream));
+
+    // Turn that deserialized picture into a Src, draw it into our Sink to fill bitmap or stream.
+    struct ProxySrc : public Src {
+        const SkPicture* fPic;
+        const SkISize fSize;
+        ProxySrc(const SkPicture* pic, SkISize size) : fPic(pic), fSize(size) {}
+
+        Error draw(SkCanvas* canvas) const SK_OVERRIDE {
+            canvas->drawPicture(fPic);
+            return "";
+        }
+        SkISize size() const SK_OVERRIDE { return fSize; }
+        Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
+    } proxy(deserialized, src.size());
+    return fSink->draw(proxy, bitmap, stream);
+}
+
+/*~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~*/
+
+ViaTiles::ViaTiles(int w, int h, SkBBHFactory* factory, Sink* sink)
+    : fW(w)
+    , fH(h)
+    , fFactory(factory)
+    , fSink(sink) {}
+
+Error ViaTiles::draw(const Src& src, SkBitmap* bitmap, SkWStream* stream) const {
+    // Record our Src into a picture.
+    SkSize size;
+    size = src.size();
+    SkPictureRecorder recorder;
+    Error err = src.draw(recorder.beginRecording(size.width(), size.height(), fFactory.get()));
+    if (!err.isEmpty()) {
+        return err;
+    }
+    SkAutoTUnref<SkPicture> pic(recorder.endRecording());
+
+    // Turn that picture into a Src that draws into our Sink via tiles + MPD.
+    struct ProxySrc : public Src {
+        const int fW, fH;
+        const SkPicture* fPic;
+        const SkISize fSize;
+        ProxySrc(int w, int h, const SkPicture* pic, SkISize size)
+            : fW(w), fH(h), fPic(pic), fSize(size) {}
+
+        Error draw(SkCanvas* canvas) const SK_OVERRIDE {
+            const int xTiles = (fSize.width()  + fW - 1) / fW,
+                      yTiles = (fSize.height() + fH - 1) / fH;
+            SkMultiPictureDraw mpd(xTiles*yTiles);
+            SkTDArray<SkSurface*> surfaces;
+            surfaces.setReserve(xTiles*yTiles);
+
+            SkImageInfo info = canvas->imageInfo().makeWH(fW, fH);
+            for (int j = 0; j < yTiles; j++) {
+                for (int i = 0; i < xTiles; i++) {
+                    // This lets our ultimate Sink determine the best kind of surface.
+                    // E.g., if it's a GpuSink, the surfaces and images are textures.
+                    SkSurface* s = canvas->newSurface(info);
+                    if (!s) {
+                        s = SkSurface::NewRaster(info);  // Some canvases can't create surfaces.
+                    }
+                    surfaces.push(s);
+                    SkCanvas* c = s->getCanvas();
+                    c->translate(SkIntToScalar(-i * fW),
+                                 SkIntToScalar(-j * fH));  // Line up the canvas with this tile.
+                    mpd.add(c, fPic);
+                }
+            }
+            mpd.draw();
+            for (int j = 0; j < yTiles; j++) {
+                for (int i = 0; i < xTiles; i++) {
+                    SkAutoTUnref<SkImage> image(surfaces[i+xTiles*j]->newImageSnapshot());
+                    canvas->drawImage(image, SkIntToScalar(i*fW), SkIntToScalar(j*fH));
+                }
+            }
+            surfaces.unrefAll();
+            return "";
+        }
+        SkISize size() const SK_OVERRIDE { return fSize; }
+        Name name() const SK_OVERRIDE { sk_throw(); return ""; }  // No one should be calling this.
+    } proxy(fW, fH, pic, src.size());
+    return fSink->draw(proxy, bitmap, stream);
+}
+
+}  // namespace DM