Merge pull request #442 from noma4i/fix/android-skip-unchanged-image-reload

fix(android): avoid redundant image reloads

Author: duguyihou

android/src/main/java/com/turboimage/TurboImageListener.kt

@@ -11,7 +11,10 @@ import com.turboimage.events.FailureEvent
 import com.turboimage.events.StartEvent
 import com.turboimage.events.SuccessEvent
 
-class TurboImageListener(private val view: TurboImageView) : ImageRequest.Listener {
+class TurboImageListener(
+  private val view: TurboImageView,
+  private val loadSignature: String
+) : ImageRequest.Listener {
 
   override fun onStart(request: ImageRequest) {
     super.onStart(request)
@@ -28,6 +31,7 @@ class TurboImageListener(private val view: TurboImageView) : ImageRequest.Listen
 
   override fun onSuccess(request: ImageRequest, result: SuccessResult) {
     super.onSuccess(request, result)
+    view.markLoadSuccess(loadSignature)
 
     val reactContext = view.context as ReactContext
     UIManagerHelper.getEventDispatcher(reactContext, view.id)?.let {
@@ -51,6 +55,7 @@ class TurboImageListener(private val view: TurboImageView) : ImageRequest.Listen
 
   override fun onError(request: ImageRequest, result: ErrorResult) {
     super.onError(request, result)
+    view.markLoadFailure(loadSignature)
 
     val reactContext = view.context as ReactContext
     UIManagerHelper.getEventDispatcher(reactContext, view.id)?.let {

android/src/main/java/com/turboimage/TurboImageView.kt

@@ -53,6 +53,65 @@ class TurboImageView(private val reactContext: ThemedReactContext) :
     }
 
   var memoryCacheKey: String? = null
+  private var activeLoadSignature: String? = null
+  private var lastSuccessfulLoadSignature: String? = null
+
+  fun shouldSkipReload(loadSignature: String): Boolean {
+    return lastSuccessfulLoadSignature == loadSignature
+  }
+
+  fun markLoadStarted(loadSignature: String) {
+    activeLoadSignature = loadSignature
+  }
+
+  fun markLoadSuccess(loadSignature: String) {
+    if (activeLoadSignature == loadSignature) {
+      lastSuccessfulLoadSignature = loadSignature
+      activeLoadSignature = null
+    }
+  }
+
+  fun markLoadFailure(loadSignature: String) {
+    if (activeLoadSignature == loadSignature) {
+      lastSuccessfulLoadSignature = null
+      activeLoadSignature = null
+    }
+  }
+
+  fun resetLoadSignature() {
+    activeLoadSignature = null
+    lastSuccessfulLoadSignature = null
+  }
+
+  fun buildLoadSignature(defaultCrossfade: Int): String {
+    val headersSignature = headers?.names()?.sorted()?.joinToString(",") { name ->
+      "$name=${headers?.values(name)?.joinToString(";")}"
+    } ?: ""
+    val indicatorSignature = indicator.entries.sortedBy { it.key }.joinToString(",") { (key, value) ->
+      "$key=$value"
+    }
+    val viewSizeSignature = if (resize == null) "${width}x${height}" else ""
+    return listOf(
+      uri,
+      headersSignature,
+      cacheKey,
+      cachePolicy,
+      crossfade ?: defaultCrossfade,
+      blurhash,
+      thumbhash,
+      memoryCacheKey,
+      indicatorSignature,
+      showPlaceholderOnFailure,
+      resize,
+      viewSizeSignature,
+      rounded,
+      blur,
+      monochrome,
+      tint,
+      allowHardware,
+      format
+    ).joinToString("|") { it?.toString() ?: "" }
+  }
 
   val circleProgressDrawable: CircularProgressDrawable?
     get() {

android/src/main/java/com/turboimage/TurboImageViewManager.kt

@@ -54,20 +54,28 @@ class TurboImageViewManager : SimpleViewManager<TurboImageView>(), LifecycleEven
 
   override fun onAfterUpdateTransaction(view: TurboImageView) {
     super.onAfterUpdateTransaction(view)
-    reloadImage(view)
+    reloadImage(view, force = false)
   }
 
   override fun onDropViewInstance(view: TurboImageView) {
     super.onDropViewInstance(view)
+    view.resetLoadSignature()
     view.dispose()
   }
 
-  private fun reloadImage(view: TurboImageView) {
+  private fun reloadImage(view: TurboImageView, force: Boolean) {
     val defaultCrossfade = if (view.thumbhashDrawable != null || view.blurhashDrawable != null) {
       0
     } else {
       CrossfadeDrawable.DEFAULT_DURATION
     }
+    val loadSignature = view.buildLoadSignature(defaultCrossfade)
+
+    if (!force && view.shouldSkipReload(loadSignature)) {
+      return
+    }
+
+    view.markLoadStarted(loadSignature)
 
     val okHttpClient = OkHttpClient.Builder()
       .addInterceptor(ProgressInterceptor(object : ProgressListener {
@@ -86,6 +94,7 @@ class TurboImageViewManager : SimpleViewManager<TurboImageView>(), LifecycleEven
       .build()
 
     val imageLoader = Coil.imageLoader(view.context).newBuilder()
+      .networkObserverEnabled(false)
       .respectCacheHeaders(view.cachePolicy == "urlCache")
       .okHttpClient(okHttpClient)
       .build()
@@ -97,7 +106,7 @@ class TurboImageViewManager : SimpleViewManager<TurboImageView>(), LifecycleEven
         diskCacheKey(it)
       }
       view.allowHardware?.let { allowHardware(it) }
-      listener(TurboImageListener(view))
+      listener(TurboImageListener(view, loadSignature))
       view.format?.let {
         when (it) {
           "svg" -> {
@@ -253,16 +262,19 @@ class TurboImageViewManager : SimpleViewManager<TurboImageView>(), LifecycleEven
 
   override fun onHostResume() {
     if (isInBackground) {
-      reloadImage(imageView)
+      reloadImage(imageView, force = true)
+      isInBackground = false
     }
   }
 
   override fun onHostPause() {
+    imageView.resetLoadSignature()
     imageView.dispose()
     isInBackground = true
   }
 
   override fun onHostDestroy() {
+    imageView.resetLoadSignature()
     imageView.dispose()
   }
 }