implement BitmapFactory.decodeStream() using gdk_pixbuf_new_from_stream

The java InputStream is wrapped into a custom GInputStream
implementation

meson.build

@@ -67,6 +67,7 @@ libtranslationlayer_so = shared_library('translation_layer_main', [
                                                                   	'src/api-impl-jni/database/android_database_SQLiteCommon.c',
                                                                   	'src/api-impl-jni/database/android_database_SQLiteConnection.c',
                                                                   	'src/api-impl-jni/drawables/ninepatch.c',
+                                                                  	'src/api-impl-jni/graphics/android_graphics_BitmapFactory.c',
                                                                   	'src/api-impl-jni/android_content_res_AssetManager.c',
                                                                   	'src/api-impl-jni/audio/android_media_AudioTrack.c',
                                                                   	'src/api-impl-jni/audio/android_media_SoundPool.c',

src/api-impl-jni/android_graphics_Bitmap.c

@@ -52,3 +52,15 @@ JNIEXPORT jboolean JNICALL Java_android_graphics_Bitmap_nativeRecycle(JNIEnv *en
 	g_object_unref(pixbuf);
 	return true;
 }
+
+JNIEXPORT jlong JNICALL Java_android_graphics_Bitmap_native_1copy(JNIEnv *env, jclass, jlong src_ptr) {
+	GdkPixbuf *src = _PTR(src_ptr);
+	GdkPixbuf *copy = gdk_pixbuf_copy(src);
+	return _INTPTR(copy);
+}
+
+JNIEXPORT jint JNICALL Java_android_graphics_Bitmap_nativeRowBytes(JNIEnv *env, jclass, jlong pixbuf_ptr) {
+	GdkPixbuf *pixbuf = _PTR(pixbuf_ptr);
+
+	return gdk_pixbuf_get_rowstride(pixbuf);
+}

src/api-impl-jni/generated_headers/android_graphics_Bitmap.h

@@ -19,6 +19,14 @@ extern "C" {
 JNIEXPORT jlong JNICALL Java_android_graphics_Bitmap_native_1bitmap_1from_1path
   (JNIEnv *, jobject, jobject);
 
+/*
+ * Class:     android_graphics_Bitmap
+ * Method:    native_copy
+ * Signature: (J)J
+ */
+JNIEXPORT jlong JNICALL Java_android_graphics_Bitmap_native_1copy
+  (JNIEnv *, jclass, jlong);
+
 /*
  * Class:     android_graphics_Bitmap
  * Method:    getWidth
@@ -86,10 +94,10 @@ JNIEXPORT void JNICALL Java_android_graphics_Bitmap_nativeErase
 /*
  * Class:     android_graphics_Bitmap
  * Method:    nativeRowBytes
- * Signature: (I)I
+ * Signature: (J)I
  */
 JNIEXPORT jint JNICALL Java_android_graphics_Bitmap_nativeRowBytes
-  (JNIEnv *, jclass, jint);
+  (JNIEnv *, jclass, jlong);
 
 /*
  * Class:     android_graphics_Bitmap

src/api-impl-jni/generated_headers/android_graphics_BitmapFactory.h

@@ -12,9 +12,9 @@ extern "C" {
 /*
  * Class:     android_graphics_BitmapFactory
  * Method:    nativeDecodeStream
- * Signature: (Ljava/io/InputStream;[BLandroid/graphics/Rect;Landroid/graphics/BitmapFactory/Options;)Landroid/graphics/Bitmap;
+ * Signature: (Ljava/io/InputStream;[BLandroid/graphics/Rect;Landroid/graphics/BitmapFactory/Options;)J
  */
-JNIEXPORT jobject JNICALL Java_android_graphics_BitmapFactory_nativeDecodeStream
+JNIEXPORT jlong JNICALL Java_android_graphics_BitmapFactory_nativeDecodeStream
   (JNIEnv *, jclass, jobject, jbyteArray, jobject, jobject);
 
 /*

src/api-impl-jni/graphics/android_graphics_BitmapFactory.c

@@ -0,0 +1,60 @@
+#include <gtk/gtk.h>
+#include <string.h>
+
+#include "../defines.h"
+#include "../util.h"
+
+#include "../generated_headers/android_graphics_BitmapFactory.h"
+
+struct _JavaInputStream
+{
+	GInputStream parent_instance;
+
+	jobject is;
+	jbyteArray storage;
+	int storage_size;
+};
+
+G_DECLARE_FINAL_TYPE(JavaInputStream, java_input_stream, ATL, JAVA_INPUT_STREAM, GInputStream);
+
+static gssize java_input_stream_read(GInputStream *gstream, void *buffer, gsize count, GCancellable *cancellable, GError **error) {
+	JavaInputStream *stream = ATL_JAVA_INPUT_STREAM(gstream);
+	JNIEnv *env = get_jni_env();
+
+	count = MIN(count, stream->storage_size);
+
+	count = (*env)->CallIntMethod(env, stream->is, _METHOD(_CLASS(stream->is), "read", "([BII)I"), stream->storage, 0, count);
+	if (count == -1) {  // end of stream
+		return 0;
+	}
+	jbyte *storage_buf = (*env)->GetByteArrayElements(env, stream->storage, NULL);
+	memcpy(buffer, storage_buf, count);
+	(*env)->ReleaseByteArrayElements(env, stream->storage, storage_buf, 0);
+
+	return count;
+}
+
+static void java_input_stream_class_init(JavaInputStreamClass *klass) {
+	klass->parent_class.read_fn  = java_input_stream_read;
+}
+
+static void java_input_stream_init(JavaInputStream *self) {
+}
+
+G_DEFINE_TYPE(JavaInputStream, java_input_stream, G_TYPE_INPUT_STREAM)
+
+static GInputStream *java_input_stream_new(JNIEnv *env, jobject is, jbyteArray storage) {
+	JavaInputStream *stream = g_object_new(java_input_stream_get_type(), NULL);
+	stream->is = is;
+	stream->storage = storage;
+	stream->storage_size = (*env)->GetArrayLength(env, storage);
+	return &stream->parent_instance;
+}
+
+JNIEXPORT jlong JNICALL Java_android_graphics_BitmapFactory_nativeDecodeStream(JNIEnv *env, jclass, jobject is, jbyteArray storage, jobject outPadding, jobject opts) {
+	GInputStream *stream = java_input_stream_new(env, is, storage);
+
+	GdkPixbuf *pixbuf = gdk_pixbuf_new_from_stream(stream, NULL, NULL);
+	g_object_unref(stream);
+	return _INTPTR(pixbuf);
+}

src/api-impl/android/graphics/Bitmap.java

@@ -136,7 +136,13 @@ public final class Bitmap {
 		mLayoutBounds = null;
 	}
 
+	Bitmap(long pixbuf) {
+		this();
+		this.pixbuf = pixbuf;
+	}
+
 	private native long native_bitmap_from_path(CharSequence path);
+	static native long native_copy(long src);
 
 	/**
 	 * Private constructor that must received an already allocated native bitmap
@@ -784,7 +790,7 @@ public final class Bitmap {
 
 				       return bitmap;
 				   */
-		return new Bitmap();
+		return new Bitmap(native_copy(source.pixbuf));
 	}
 
 	/**
@@ -1606,7 +1612,7 @@ public final class Bitmap {
 						     int quality, OutputStream stream,
 						     byte[] tempStorage);
 	private static native void nativeErase(int nativeBitmap, int color);
-	private static native int nativeRowBytes(int nativeBitmap);
+	private static native int nativeRowBytes(long nativeBitmap);
 	private static native int nativeConfig(int nativeBitmap);
 
 	private static native int nativeGetPixel(int nativeBitmap, int x, int y,

src/api-impl/android/graphics/BitmapFactory.java

@@ -596,7 +596,7 @@ public class BitmapFactory {
 			tempStorage = opts.inTempStorage;
 		if (tempStorage == null)
 			tempStorage = new byte[DECODE_BUFFER_SIZE];
-		return nativeDecodeStream(is, tempStorage, outPadding, opts);
+		return new Bitmap(nativeDecodeStream(is, tempStorage, outPadding, opts));
 	}
 
 	/**
@@ -669,7 +669,7 @@ public class BitmapFactory {
 		return decodeFileDescriptor(fd, null, null);
 	}
 
-	private static native Bitmap nativeDecodeStream(InputStream is, byte[] storage,
+	private static native long nativeDecodeStream(InputStream is, byte[] storage,
 							Rect padding, Options opts);
 	private static native Bitmap nativeDecodeFileDescriptor(FileDescriptor fd,
 								Rect padding, Options opts);