Shapedetection module: Blink side implementation

third_party/WebKit/Source/modules/shapedetection/FaceDetector.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/shapedetection/FaceDetector.h"
 
-#include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
+#include "core/dom/DOMRect.h"
+#include "core/dom/Document.h"
+#include "core/fetch/ImageResource.h"
+#include "core/frame/LocalFrame.h"
+#include "core/html/HTMLImageElement.h"
+#include "platform/graphics/Image.h"
+#include "public/platform/InterfaceProvider.h"
+#include "third_party/skia/include/core/SkImage.h"
+#include "third_party/skia/include/core/SkImageInfo.h"
 
 namespace blink {
 
-FaceDetector* FaceDetector::create()
+namespace {
+
+mojo::ScopedSharedBufferHandle getSharedBufferHandle(const HTMLImageElement* img)
 {
-    return new FaceDetector();
+    ImageResource* imgResource = img->cachedImage();

[mcasas, 2016/09/30 02:14:59]

ImageResource* const ?

[xianglu, 2016/09/30 16:37:41]

Done.

+    if (!imgResource) {
+        DLOG(ERROR) << "Failed to convert HTMLImageElement to ImageSource.";
+        return mojo::ScopedSharedBufferHandle();
+    }
+
+    Image* blinkImage = imgResource->getImage();

[mcasas, 2016/09/30 02:14:59]

Image* const ?

[xianglu, 2016/09/30 16:37:41]

Done.

+    if (!blinkImage) {
+        DLOG(ERROR) << "Failed to convert ImageSource to blink::Image.";
+        return mojo::ScopedSharedBufferHandle();
+    }
+
+    sk_sp<SkImage> skImg = blinkImage->imageForCurrentFrame();

[mcasas, 2016/09/30 02:14:59]

const sk_sp<SkImage> skiaImage ?

[xianglu, 2016/09/30 16:37:40]

Done.

+    if (!skImg) {
+        DLOG(ERROR) << "Failed to convert blink::Image to sk_sp<SkImage>.";
+        return mojo::ScopedSharedBufferHandle();
+    }
+
+    SkImageInfo dstInfo = SkImageInfo::MakeN32(skImg->width(), skImg->height(), skImg->alphaType());

[mcasas, 2016/09/30 02:14:59]

const SkImageInfo skiaInfo ?

[xianglu, 2016/09/30 16:37:41]

Done.

+
+    uint32_t allocationSize = dstInfo.getSafeSize(dstInfo.minRowBytes());

[mcasas, 2016/09/30 02:14:59]

const 

[xianglu, 2016/09/30 16:37:41]

Done.

+    mojo::ScopedSharedBufferHandle sharedBufferHandle = mojo::SharedBufferHandle::Create(allocationSize);
+    mojo::ScopedSharedBufferMapping mappingPtr = sharedBufferHandle->Map(allocationSize);
+    DCHECK(mappingPtr);
+
+    SkPixmap pixmap(dstInfo, mappingPtr.get(), dstInfo.minRowBytes());

[mcasas, 2016/09/30 02:14:59]

const 

[xianglu, 2016/09/30 16:37:41]

Done.

+    if (!skImg->readPixels(pixmap, 0, 0)) {
+        DLOG(ERROR) << "Failed to read pixels from sk_sp<SkImage>.";
+        return mojo::ScopedSharedBufferHandle();
+    }
+
+    DCHECK_EQ(img->naturalWidth(), skImg->width());
+    DCHECK_EQ(img->naturalHeight(), skImg->height());

[mcasas, 2016/09/30 02:14:59]

Move these two contracts/preconditions to l.37,
i.e. as close as possible to |skImage| declaration
as possible.

[xianglu, 2016/09/30 16:37:40]

Done.

+    return sharedBufferHandle;
 }
 
-ScriptPromise FaceDetector::detect(ScriptState* scriptState, const HTMLImageElement* image)
+} // anonymous namespace
+
+FaceDetector* FaceDetector::create(const Document& document)
+{
+    return new FaceDetector(*document.frame());
+}
+
+FaceDetector::FaceDetector(LocalFrame& frame)
+{
+    DCHECK(!m_service.is_bound());
+    DCHECK(frame.interfaceProvider());
+    frame.interfaceProvider()->getInterface(mojo::GetProxy(&m_service));
+}
+
+ScriptPromise FaceDetector::detect(ScriptState* scriptState, const HTMLImageElement* img)
 {
     ScriptPromiseResolver* resolver = ScriptPromiseResolver::create(scriptState);
     ScriptPromise promise = resolver->promise();
-    resolver->reject(DOMException::create(NotSupportedError, "Not implemented"));
+
+    if (!m_service) {
+        resolver->reject(DOMException::create(NotFoundError, "Face detection service unavailable."));
+        return promise;
+    }
+
+    if (!img) {
+        resolver->reject(DOMException::create(SyntaxError, "The provided HTMLImageElement is empty."));
+        return promise;
+    }
+
+    // TODO(xianglu): Add security check when the spec is ready. https://crbug.com/646083
+    mojo::ScopedSharedBufferHandle sharedBufferHandle = getSharedBufferHandle(img);
+    if (!sharedBufferHandle->is_valid()) {
+        resolver->reject(DOMException::create(SyntaxError, "Failed to get sharedBufferHandle."));
+        return promise;
+    }
+
+    m_serviceRequests.add(resolver);
+    DCHECK(m_service.is_bound());
+    m_service->DetectFace(
+        std::move(sharedBufferHandle),
+        img->naturalWidth(), img->naturalHeight(),

[mcasas, 2016/09/30 02:14:59]

Strange indenting: either all parameters are in the
same line, or these two should go on different lines.
Should be easier to solve after Friday when Blink
style converges to Cr style though.

[xianglu, 2016/09/30 16:37:41]

Done.

+        convertToBaseCallback(WTF::bind(&FaceDetector::onDetectFace, wrapPersistent(this), wrapPersistent(resolver)))
+        );
+    sharedBufferHandle.reset();
     return promise;
 }
 
+
+void FaceDetector::onDetectFace(ScriptPromiseResolver* resolver, mojo::WTFArray<mojom::blink::BoundingBoxPtr> boundingBoxes)
+{
+    if (!m_serviceRequests.contains(resolver))
+        return;
+
+    HeapVector<Member<DOMRect>> resultRects;
+    for (size_t i = 0; i < boundingBoxes.size(); i++) {
+        resultRects.append(DOMRect::create(
+            boundingBoxes.at(i)->x,
+            boundingBoxes.at(i)->y,
+            boundingBoxes.at(i)->width,
+            boundingBoxes.at(i)->height));
+    }

[mcasas, 2016/09/30 02:14:59]

Consider for-range loop and const auto&: 

    HeapVector<Member<DOMRect>> detectedFaces;
    for (const auto& boundingBox : boundingBoxes) {
        detectedFaces.append(DOMRect::create(boundingBox.x, boundingBox.y,
boundingBox.width, boundingBox.height));
    }

[xianglu, 2016/09/30 16:37:41]

There is no begin() function in mojo::WTFArray.

+
+    resolver->resolve(resultRects);
+    m_serviceRequests.remove(resolver);
+}
+
+DEFINE_TRACE(FaceDetector)
+{
+    visitor->trace(m_serviceRequests);
+}
+
 } // namespace blink