feat: Add zero-copy SharedArray type to Frame Processor Plugins (#2383)

* feat: Create `TypedArray` class for Frame Processor Plugins

* Type

* feat: Pass `VisionCameraProxy` along (BREAKING)

* feat: Finish implementation

* Log a bit

* feat: Successfully convert JSI <> JNI buffers

* Wrap buffer

* fix: Fix using wrong Runtime

* feat: Add docs

* add zero copy example

* Format C++

* Create iOS base

* feat: Finish iOS implementation

* chore: Format

* fix: Use `NSData` instead of `NSMutableData`

* Format

* fix: Fix build when Frame Processors are disabled

* chore: Rename `TypedArray` to `SharedArray`

* fix: Fix Swift typings for Array

* Remove a few default inits

* fix: Fix Android build

* fix: Use `NSInteger`

* Update SharedArray.mm

* fix: Expose bytes directly on iOS (NSData was immutable)

package/android/src/main/java/com/mrousavy/camera/frameprocessor/FrameProcessorPlugin.java

@@ -23,9 +23,8 @@ public abstract class FrameProcessorPlugin {
      * The initializer of this Frame Processor Plugin.
      * This is called everytime this Frame Processor Plugin is loaded from the JS side (`initFrameProcessorPlugin(..)`).
      * Optionally override this method to implement custom initialization logic.
-     * @param options An options dictionary passed from the JS side, or null if none.
      */
-    public FrameProcessorPlugin(@Nullable Map<String, Object> options) {}
+    public FrameProcessorPlugin() { }
 
     /**
      * The actual Frame Processor Plugin's implementation that runs when `plugin.call(..)` is called in the JS Frame Processor.

package/android/src/main/java/com/mrousavy/camera/frameprocessor/FrameProcessorPluginRegistry.java

@@ -2,6 +2,7 @@ package com.mrousavy.camera.frameprocessor;
 
 import android.util.Log;
 import androidx.annotation.Keep;
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import com.facebook.proguard.annotations.DoNotStrip;
 import java.util.Map;
@@ -24,7 +25,7 @@ public class FrameProcessorPluginRegistry {
 
     @DoNotStrip
     @Keep
-    public static FrameProcessorPlugin getPlugin(String name, Map<String, Object> options) {
+    public static FrameProcessorPlugin getPlugin(String name, VisionCameraProxy proxy, Map<String, Object> options) {
         Log.i(TAG, "Looking up Frame Processor Plugin \"" + name + "\"...");
         PluginInitializer initializer = Plugins.get(name);
         if (initializer == null) {
@@ -32,10 +33,10 @@ public class FrameProcessorPluginRegistry {
             return null;
         }
         Log.i(TAG, "Frame Processor Plugin \"" + name + "\" found! Initializing...");
-        return initializer.initializePlugin(options);
+        return initializer.initializePlugin(proxy, options);
     }
 
     public interface PluginInitializer {
-        FrameProcessorPlugin initializePlugin(@Nullable Map<String, Object> options);
+        FrameProcessorPlugin initializePlugin(@NonNull VisionCameraProxy proxy, @Nullable Map<String, Object> options);
     }
 }

package/android/src/main/java/com/mrousavy/camera/frameprocessor/SharedArray.java

@@ -0,0 +1,59 @@
+package com.mrousavy.camera.frameprocessor;
+
+import androidx.annotation.Keep;
+
+import com.facebook.jni.HybridData;
+import com.facebook.proguard.annotations.DoNotStrip;
+
+import java.nio.ByteBuffer;
+
+/**
+ * A JSI TypedArray/ArrayBuffer implementation used for passing buffers between JS and Native without copying data.
+ * ByteBuffers are used for efficient data transfer.
+ *
+ * @noinspection JavaJniMissingFunction
+ */
+public final class SharedArray {
+    @DoNotStrip
+    @Keep
+    private final HybridData mHybridData;
+
+    @DoNotStrip
+    @Keep
+    public SharedArray(HybridData hybridData) {
+        mHybridData = hybridData;
+    }
+
+    /**
+     * Allocate a new SharedArray. Use `getByteBuffer` to obtain a reference to the direct ByteBuffer for writing.
+     * @param proxy The VisionCamera Proxy from the Frame Processor Plugin's initializer.
+     * @param dataType The ArrayBuffer's data type. `Type.Int8Array` = `Int8Array` in JS
+     * @param size The size of the ArrayBuffer.
+     */
+    public SharedArray(VisionCameraProxy proxy, Type dataType, int size) {
+        mHybridData = initHybrid(proxy, dataType.ordinal(), size);
+    }
+
+    /**
+     * Gets the direct ByteBuffer that can be used to directly update the JSI ArrayBuffer.
+     */
+    public native ByteBuffer getByteBuffer();
+
+    private native HybridData initHybrid(VisionCameraProxy proxy, int dataType, int size);
+
+    /**
+     * The Type of the SharedArray.
+     */
+    public enum Type {
+        // Values start at 0 and need to match with JSITypedArray.h::TypedArrayKind
+        Int8Array,
+        Int16Array,
+        Int32Array,
+        Uint8Array,
+        Uint8ClampedArray,
+        Uint16Array,
+        Uint32Array,
+        Float32Array,
+        Float64Array,
+    }
+}

package/android/src/main/java/com/mrousavy/camera/frameprocessor/VisionCameraProxy.kt

@@ -72,7 +72,7 @@ class VisionCameraProxy(context: ReactApplicationContext) {
   @DoNotStrip
   @Keep
   fun initFrameProcessorPlugin(name: String, options: Map<String, Any>): FrameProcessorPlugin =
-    FrameProcessorPluginRegistry.getPlugin(name, options)
+    FrameProcessorPluginRegistry.getPlugin(name, this, options)
 
   // private C++ funcs
   private external fun initHybrid(jsContext: Long, jsCallInvokerHolder: CallInvokerHolderImpl, scheduler: VisionCameraScheduler): HybridData