> Yes, certainly.
I assume it means LGTM from you. :) Thanks!
>
> Since I'm neither architect nor owner, you need to get LGTMs from them :-)
Ping @Halton for extension, @Lin for Android and @Alexis for overall. Please
take a look.
Thanks,
-ningxin
>
> On 7/17/15 17:44 , "Hu, Ningxin" <ningxin...@intel.com> wrote:
>
> >Hi Zhenyu,
> >
> >>
> >> My suggestion is to introduce a new version of current messaging
> >>interface instead of a whole new interface.
> >>
> >> struct XW_MessagingInterface_2 {
> >>
> >> void (*Register)(XW_Extension extension, XW_HandleMessageCallback
> >> handle_message);
> >> void (*PostMessage)(XW_Instance instance, const char* message);
> >>
> >> void (*RegisterBinaryMessageCallback)(XW_Extension extension,
> >> XW_HandleBinaryMessageCallback handle_message);
> >> void (*PostBinaryMessage)(XW_Instance instance, const char*
> >> message, const size_t size); };
> >>
> >
> >Thanks for your suggestion.
> >
> >XW_MessagingInterface_2 looks better than
> >XW_BinaryMessagingInterface_1, as the binary messaging API is an
> >enhancement to the async messaging interface. And it looks consistent to
> Java API proposal.
> >
> >I will integrate this change into my design.
> >
> >With this change, does it look good you?
> >
> >Thanks,
> >-ningxin
> >
> >> Thanks,
> >>
> >> Zhenyu
> >>
> >> On 7/16/15 15:25 , "Hu, Ningxin" <ningxin...@intel.com> wrote:
> >>
> >> >Intent to Implement: Binary Messaging Interface for Crosswalk
> >> >External Extension
> >> >
> >> >Description:
> >> >Today's Crosswalk external extension API only provides text based
> >> >messaging interface. However, coming use cases require the external
> >> >extension native code to exchange binary data with JavaScript code.
> >> >For example, an external extension wants to transfer the images
> >> >stream from native to JavaScript in real-time (30FPS at least). With
> >> >today's external extension messaging API, the extension has to
> >> >encode the binary image data into text in native first, posts to
> >> >JavaScript and then decodes from the text to binary data in
> >> >JavaScript. The encoding, decoding (in
> >> >JavaScript!) and increased message size leads to low performance.
> >> >Experiment shows by using base64 to transfer VGA (640x480) images,
> >> >this approach can only deliver less 10 FPS on mainstream PC.
> >> >The binary messaging interface is proposed to added into Crosswalk
> >> >external extension API. It allows native code to exchange binary
> >> >data (a byte array) to JavaScript without unnecessary
> encoding/decoding.
> >> >JavaScript receives an ArrayBuffer object and can access the binary
> >> >data via different Typed Array View. Vice versa, JavaScript can send
> >> >the binary data in an ArrayBuffer object to native, native code
> >> >receives a byte array.
> >> >Prototype shows 3X-8X (binary messaging vs. text messaging)
> >> >performance speedup when transferring different size of data on both
> >> >PC and mobile device. Initial data shows with binary messaging
> >> >interface, an external extension is able to transfer VGA images at
> 60FPS on PC.
> >> >
> >> >Affected component: Crosswalk External Extension
> >> >
> >> >Related feature:
> >> >https://crosswalk-project.org/jira/browse/XWALK-4615
> >> >
> >> >Target release: Crosswalk-17
> >> >
> >> >Implementation details:
> >> >1. Interface change:
> >> >For Crosswalk External Extension C API, a new interface
> >> >XW_BinaryMessagingInterface_1 will be added. To keep API and ABI
> >> >compatibility with existing external extension, a new file
> >> >(extensions/public/XW_Extension_BinaryMessage.h) will be added to
> >> >contain the XW_BinaryMessagingInterface_1 interface. The
> >> >XW_BinaryMessagingInterface_1 looks like:
> >> >
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >/////////////////
> >> >#ifdef __cplusplus
> >> >extern "C" {
> >> >#endif
> >> >
> >> >#define XW_BINARY_MESSAGING_INTERFACE_1
> "XW_BinaryMessagingInterface_1"
> >> >#define XW_BINARY_MESSAGING_INTERFACE
> >> >XW_BINARY_MESSAGING_INTERFACE_1
> >> >
> >> >typedef void (*XW_HandleBinaryMessageCallback)(XW_Instance instance,
> >> >
> >> > const char* message,
> >> >
> >> > const size_t size);
> >> >
> >> >struct XW_BinaryMessagingInterface_1 {
> >> > void (*Register)(XW_Extension extension,
> >> > XW_HandleBinaryMessageCallback
> >> >handle_message);
> >> >
> >> > void (*PostMessage)(XW_Instance instance, const char* message,
> >> >const size_t size); };
> >> >
> >> >typedef struct XW_BinaryMessagingInterface_1
> >> >XW_BinaryMessagingInterface;
> >> >
> >> >#ifdef __cplusplus
> >> >} // extern "C"
> >> >#endif
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >////////////////
> >> >
> >> >If the C extension wants to use binary messaging, it needs to query
> >> >the "XW_BinaryMessagingInterface_1" interface and use the
> >> >PostMessage method to post binary data to JavaScript. On other hand,
> >> >it needs to register a XW_HandleBinaryMessageCallback to receive
> >> >binary data from
> >> JavaScript.
> >> >
> >> >For Crosswalk external extension Android Java API, two methods will
> >> >be added into XWalkExtensionClient interface:
> >> >
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >///////////////
> >> >
> >> >public void onBinaryMessage(int extensionInstanceID, byte[]
> >> >message);
> >> >
> >> >public final void postBinaryMessage(int instanceID, byte[] message);
> >> >
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >//////////////
> >> >
> >> >Java extension which inherits XWalkExtensionClient can use
> >> >postBinaryMesssage to post binary data to JavaScript and implements
> >> >onBinaryMessage to receive binary data from JavaScript.
> >> >
> >> >No new APIs will be added into Crosswalk extension JavaScript API.
> >> >When native external extension posts binary message, the JavaScript
> >> >message listener receives an ArrayBuffer object.
> >> >When JavaScript invokes extension.postMessage with an ArrayBuffer
> >> >object as argument, the native binary message listener is invoked.
> >> >
> >> >This proposal doesn't cover binary messaging support in SyncMessage,
> >> >as there is no obvious use case.
> >> >
> >> >Sample code:
> >> >An external extension wants to transfer image data to JavaScript. To
> >> >transfer structured data, the extension can use simple custom binary
> >> >message format as this sample shows. Or it can leverage more
> >> >sophisticated binary format, e.g. Google's Protocol Buffer
> >> >(https://developers.google.com/protocol-buffers/).
> >> >C++:
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >/////////////
> >> >// image binary format
> >> >// uint32_t width;
> >> >// uint32_t height;
> >> >// char data[width * height * 4];
> >> >
> >> >static const XW_BinaryMessagingInterface* g_binary_messaging =
> >> > get_interface(XW_BINARY_MESSAGING_INTERFACE);
> >> >.....
> >> >size_t buffer_size = sizeof(uint32_t) + sizeof(uint32_t) +
> >> >width*height*4*sizeof(char);
> >> >char* buffer = new char[buffer_size ];
> >> >uint32_t* uint32_array = reinterpret_cast<uint32_t*>(buffer);
> >> >uint32_array[0] = image.width();
> >> >uint32_array[1] = image.height();
> >> >char* data = buffer + 2 * sizeof(uint32_t);
> >> >image.CopyImageData(data); g_binary_messaging->postMessage(instance,
> >> >buffer, buffer_size); delete[] buffer;
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >/////////////
> >> >
> >> >JavaScript:
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >/////////////
> >> >extension.setMessageListener(function(msg) {
> >> > if (msg instaceof ArrayBuffer) {
> >> > var uint32_view = new Uint32Array(msg);
> >> > var width = uint32_view[0];
> >> > var height = uint32_view[1];
> >> > var data = new Uint8Array(msg, 8, width*height*4);
> >> > ....
> >> > }
> >> >}
> >> >////////////////////////////////////////////////////////////////////
> >> >///
> >> >///
> >> >////////////
> >> >
> >> >Details:
> >> >It doesn't require to modify Crosswalk Core Extension code
> >> >(XWalkExtensionModule), as V8ValueConverter already supports to
> >> >convert a base::BinaryValue object to V8 ArrayBuffer object and vice
> versa.
> >> >
> >> >It mainly requires to modify the external extension components, to
> >> >expose the binary interface and convert the binary data to
> >> >base::BinaryValue and vice versa.
> >> >
> >> >For C external extension, files to be modified:
> >> >extensions/common/xwalk_external_adapter.cc
> >> >extensions/common/xwalk_external_adapter.h
> >> >extensions/common/xwalk_external_extension.cc
> >> >extensions/common/xwalk_external_extension.h
> >> >extensions/common/xwalk_external_instance.cc
> >> >extensions/common/xwalk_external_instance.h
> >> >extensions/extensions.gyp
> >> >
> >> >new file:
> >> >extensions/public/XW_Extension_BinaryMessage.h
> >> >
> >> >For Java external extension, files to be modified:
> >> >app/android/runtime_client/src/org/xwalk/app/runtime/extension/XWalk
> >> >Cor
> >> >eEx
> >> >tensionBridge.java
> >> >app/android/runtime_client/src/org/xwalk/app/runtime/extension/XWalk
> >> >Ext
> >> >ens
> >> >ionClient.java
> >> >app/android/runtime_client/src/org/xwalk/app/runtime/extension/XWalk
> >> >Ext
> >> >ens
> >> >ionContextClient.java
> >> >app/android/runtime_client/src/org/xwalk/app/runtime/extension/XWalk
> >> >Run
> >> >tim
> >> >eExtensionBridge.java
> >> >app/android/runtime_client/src/org/xwalk/app/runtime/extension/XWalk
> >> >Run
> >> >tim
> >> >eExtensionManager.java
> >> >extensions/android/java/src/org/xwalk/core/internal/extensions/XWalk
> >> >Ext
> >> >ens
> >> >ionAndroid.java
> >> >extensions/common/android/xwalk_extension_android.cc
> >> >extensions/common/android/xwalk_extension_android.h
> >> >runtime/android/core_internal/src/org/xwalk/core/internal/XWalkExten
> >> >sio
> >> >nIn
> >> >ternal.java
> >> >
> >> >
> >> >Thanks,
> >> >-ningxin
> >> >
> >> >_______________________________________________
> >> >Crosswalk-dev mailing list
> >> >Crosswalk-dev@lists.crosswalk-project.org
> >> >https://lists.crosswalk-project.org/mailman/listinfo/crosswalk-dev
> >
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