Fix issue with gif search and emoji loading on lowmem devices.

app/src/main/java/org/thoughtcrime/securesms/emoji/EmojiBitmapDecoder.kt

@@ -0,0 +1,40 @@
+package org.thoughtcrime.securesms.emoji
+
+import android.graphics.Bitmap
+import android.graphics.BitmapFactory
+import com.bumptech.glide.load.Option
+import com.bumptech.glide.load.Options
+import com.bumptech.glide.load.ResourceDecoder
+import com.bumptech.glide.load.engine.Resource
+import com.bumptech.glide.load.engine.bitmap_recycle.BitmapPool
+import com.bumptech.glide.load.resource.bitmap.BitmapResource
+import java.io.InputStream
+
+/**
+ * Allows fine grain control over how we decode Emoji pages via a scale factor.
+ *
+ * This can be set via RequestOptions on a Glide request:
+ *
+ * ```
+ * .apply(RequestOptions().set(EmojiBitmapDecoder.OPTION, inSampleSize)
+ * ```
+ */
+class EmojiBitmapDecoder(private val bitmapPool: BitmapPool) : ResourceDecoder<InputStream, Bitmap> {
+
+  override fun handles(source: InputStream, options: Options): Boolean {
+    return options.get(OPTION)?.let { it > 1 } ?: false
+  }
+
+  override fun decode(source: InputStream, width: Int, height: Int, options: Options): Resource<Bitmap>? {
+    val bitmapOptions = BitmapFactory.Options()
+
+    bitmapOptions.inSampleSize = requireNotNull(options.get(OPTION))
+
+    return BitmapResource.obtain(BitmapFactory.decodeStream(source, null, bitmapOptions), bitmapPool)
+  }
+
+  companion object {
+    @JvmField
+    val OPTION: Option<Int> = Option.memory("emoji_sample_size", 1)
+  }
+}