Use Widget as content type in LazyListUpdateProcessor

redwood-lazylayout-dom/src/commonMain/kotlin/app/cash/redwood/lazylayout/dom/HTMLLazyList.kt

@@ -45,9 +45,9 @@ internal class HTMLLazyList(document: Document) : LazyList<HTMLElement> {
     override fun deleteRows(index: Int, count: Int) {
     }
 
-    override fun setContent(view: HTMLElement, content: HTMLElement?, modifier: Modifier) {
-      if (content != null) {
-        view.appendChild(content)
+    override fun setContent(view: HTMLElement, widget: Widget<HTMLElement>?) {
+      if (widget != null) {
+        view.appendChild(widget.value)
       }
     }
   }

redwood-lazylayout-uiview/src/commonMain/kotlin/app/cash/redwood/lazylayout/uiview/UIViewLazyList.kt

@@ -124,8 +124,6 @@ internal class UIViewLazyList :
   private var updateProcessor: LazyListUpdateProcessor<LazyListContainerCell, UIView>? = object : LazyListUpdateProcessor<LazyListContainerCell, UIView>() {
     override fun createPlaceholder(original: UIView) = SizeOnlyPlaceholder(original)
 
-    override fun isSizeOnlyPlaceholder(placeholder: UIView) = placeholder is SizeOnlyPlaceholder
-
     override fun insertRows(index: Int, count: Int) {
       rowCount += count
       val tableView = [email protected] ?: error("detached")
@@ -156,8 +154,8 @@ internal class UIViewLazyList :
       tableView.endUpdates()
     }
 
-    override fun setContent(view: LazyListContainerCell, content: UIView?, modifier: Modifier) {
-      view.setContent(content)
+    override fun setContent(view: LazyListContainerCell, widget: Widget<UIView>?) {
+      view.setContent(widget?.value)
     }
 
     override fun detach(view: LazyListContainerCell) {

redwood-lazylayout-view/src/main/kotlin/app/cash/redwood/lazylayout/view/ViewLazyList.kt

@@ -73,9 +73,6 @@ internal class ViewLazyList private constructor(
     override fun createPlaceholder(original: View) =
       SizeOnlyPlaceholder(original, value.context)
 
-    override fun isSizeOnlyPlaceholder(placeholder: View) =
-      placeholder is SizeOnlyPlaceholder
-
     override fun insertRows(index: Int, count: Int) {
       adapter.notifyItemRangeInserted(index, count)
     }
@@ -84,8 +81,8 @@ internal class ViewLazyList private constructor(
       adapter.notifyItemRangeRemoved(index, count)
     }
 
-    override fun setContent(view: ViewHolder, content: View?, modifier: Modifier) {
-      view.content = content
+    override fun setContent(view: ViewHolder, widget: Widget<View>?) {
+      view.content = widget?.value
     }
   }
 

redwood-lazylayout-widget/api/redwood-lazylayout-widget.api

@@ -36,11 +36,10 @@ public abstract class app/cash/redwood/lazylayout/widget/LazyListUpdateProcessor
 	public final fun getPlaceholder ()Lapp/cash/redwood/widget/Widget$Children;
 	public final fun getSize ()I
 	protected abstract fun insertRows (II)V
-	protected fun isSizeOnlyPlaceholder (Ljava/lang/Object;)Z
 	public final fun itemsAfter (I)V
 	public final fun itemsBefore (I)V
 	public final fun onEndChanges ()V
-	protected abstract fun setContent (Ljava/lang/Object;Ljava/lang/Object;Lapp/cash/redwood/Modifier;)V
+	protected abstract fun setContent (Ljava/lang/Object;Lapp/cash/redwood/widget/Widget;)V
 }
 
 public final class app/cash/redwood/lazylayout/widget/LazyListUpdateProcessor$Binding {

redwood-lazylayout-widget/api/redwood-lazylayout-widget.klib.api

@@ -62,7 +62,7 @@ abstract class <#A: kotlin/Any, #B: kotlin/Any> app.cash.redwood.lazylayout.widg
 
     abstract fun deleteRows(kotlin/Int, kotlin/Int) // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.deleteRows|deleteRows(kotlin.Int;kotlin.Int){}[0]
     abstract fun insertRows(kotlin/Int, kotlin/Int) // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.insertRows|insertRows(kotlin.Int;kotlin.Int){}[0]
-    abstract fun setContent(#A, #B?, app.cash.redwood/Modifier) // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.setContent|setContent(1:0;1:1?;app.cash.redwood.Modifier){}[0]
+    abstract fun setContent(#A, app.cash.redwood.widget/Widget<#B>?) // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.setContent|setContent(1:0;app.cash.redwood.widget.Widget<1:1>?){}[0]
     final fun bind(kotlin/Int, #A): app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.Binding<#A, #B> // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.bind|bind(kotlin.Int;1:0){}[0]
     final fun getOrCreateView(kotlin/Int, kotlin/Function1<app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.Binding<#A, #B>, #A>): #A // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.getOrCreateView|getOrCreateView(kotlin.Int;kotlin.Function1<app.cash.redwood.lazylayout.widget.LazyListUpdateProcessor.Binding<1:0,1:1>,1:0>){}[0]
     final fun itemsAfter(kotlin/Int) // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.itemsAfter|itemsAfter(kotlin.Int){}[0]
@@ -71,7 +71,6 @@ abstract class <#A: kotlin/Any, #B: kotlin/Any> app.cash.redwood.lazylayout.widg
     open fun createPlaceholder(#B): #B? // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.createPlaceholder|createPlaceholder(1:1){}[0]
     open fun detach(#A) // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.detach|detach(1:0){}[0]
     open fun detach() // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.detach|detach(){}[0]
-    open fun isSizeOnlyPlaceholder(#B): kotlin/Boolean // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.isSizeOnlyPlaceholder|isSizeOnlyPlaceholder(1:1){}[0]
 
     final class <#A1: kotlin/Any, #B1: kotlin/Any> Binding { // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.Binding|null[0]
         final val isBound // app.cash.redwood.lazylayout.widget/LazyListUpdateProcessor.Binding.isBound|{}isBound[0]

redwood-lazylayout-widget/src/commonMain/kotlin/app/cash/redwood/lazylayout/widget/LazyListUpdateProcessor.kt

@@ -42,13 +42,13 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
     get() = itemsBefore.nonNullElements + loadedItems + itemsAfter.nonNullElements
 
   /** Pool of placeholder widgets. */
-  private val placeholdersQueue = ArrayDeque<W>()
+  private val placeholdersQueue = ArrayDeque<Widget<W>>()
 
   /**
    * The first placeholder ever returned. We use it to choose measured dimensions for created
    * placeholders if the pool ever runs out.
    */
-  private var firstPlaceholder: W? = null
+  private var firstPlaceholder: Widget<W>? = null
 
   /** Loaded items that may or may not have a view bound. */
   private var loadedItems = mutableListOf<Binding<V, W>>()
@@ -68,8 +68,8 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
 
     override fun insert(index: Int, widget: Widget<W>) {
       _widgets += widget
-      if (firstPlaceholder == null) firstPlaceholder = widget.value
-      placeholdersQueue += widget.value
+      if (firstPlaceholder == null) firstPlaceholder = widget
+      placeholdersQueue += widget
     }
 
     override fun move(fromIndex: Int, toIndex: Int, count: Int) {
@@ -244,7 +244,7 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
           for (i in 0 until edit.widgets.size) {
             val index = itemsBefore.size + edit.index + i
             val binding = Binding(this).apply {
-              setContentAndModifier(edit.widgets[i])
+              setContent(edit.widgets[i])
             }
             loadedItems.add(edit.index + i, binding)
 
@@ -336,7 +336,7 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
     // No binding for this index. Create one.
     if (binding == null) {
       return Binding(this).apply {
-        setContentAndModifier(loadedContent)
+        setContent(loadedContent)
       }
     }
 
@@ -346,7 +346,7 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
       recyclePlaceholder(binding.content)
     }
     binding.isPlaceholder = false
-    binding.setContentAndModifier(loadedContent)
+    binding.setContent(loadedContent)
     return binding
   }
 
@@ -357,9 +357,9 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
     if (!loaded.isBound) return null
 
     // Show the placeholder in the bound view.
-    val placeholderContent = loaded.processor.takePlaceholder()
-    if (placeholderContent != null) {
-      loaded.setContentAndModifier(placeholderContent, Modifier)
+    val placeholder = loaded.processor.takePlaceholder()
+    if (placeholder != null) {
+      loaded.setContent(placeholder)
     }
     loaded.isPlaceholder = true
     return loaded
@@ -396,7 +396,7 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
       isPlaceholder = true,
     ).apply {
       val placeholder = takePlaceholder() ?: return@apply // Detached.
-      setContentAndModifier(placeholder, Modifier)
+      setContent(placeholder)
     }
 
     return when {
@@ -406,17 +406,21 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
     }
   }
 
-  private fun takePlaceholder(): W? {
+  private fun takePlaceholder(): Widget<W>? {
     val result = placeholdersQueue.removeFirstOrNull()
     if (result != null) return result
 
     val firstPlaceholder = this.firstPlaceholder ?: return null // Detached.
-    return createPlaceholder(firstPlaceholder)
+    val sizeOnlyPlaceholderValue = createPlaceholder(firstPlaceholder.value) ?: return null
+    return SizeOnlyPlaceholderWidget(
+      value = sizeOnlyPlaceholderValue,
+      modifier = firstPlaceholder.modifier,
+    )
   }
 
-  private fun recyclePlaceholder(placeholder: W?) {
+  private fun recyclePlaceholder(placeholder: Widget<W>?) {
     if (placeholder == null) return // Detached.
-    if (!isSizeOnlyPlaceholder(placeholder)) {
+    if (placeholder !is SizeOnlyPlaceholderWidget) {
       placeholdersQueue += placeholder
     }
   }
@@ -429,13 +433,11 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
    */
   protected open fun createPlaceholder(original: W): W? = null
 
-  protected open fun isSizeOnlyPlaceholder(placeholder: W): Boolean = false
-
   protected abstract fun insertRows(index: Int, count: Int)
 
   protected abstract fun deleteRows(index: Int, count: Int)
 
-  protected abstract fun setContent(view: V, content: W?, modifier: Modifier)
+  protected abstract fun setContent(view: V, widget: Widget<W>?)
 
   protected open fun detach(view: V) {
   }
@@ -478,21 +480,14 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
      * This may also be null if it should be a placeholder but the enclosing LazyList is detached.
      * This could happen if the user scrolls the table after the view is detached.
      */
-    internal var content: W? = null
+    internal var content: Widget<W>? = null
       private set
 
-    private var modifier: Modifier = Modifier
-
-    internal fun setContentAndModifier(widget: Widget<W>) {
-      setContentAndModifier(widget.value, widget.modifier)
-    }
-
-    internal fun setContentAndModifier(content: W, modifier: Modifier) {
+    internal fun setContent(content: Widget<W>) {
       this.content = content
-      this.modifier = modifier
 
       val view = this.view
-      if (view != null) processor.setContent(view, content, modifier)
+      if (view != null) processor.setContent(view, content)
     }
 
     public fun bind(view: V) {
@@ -503,14 +498,14 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
       }
 
       this.view = view
-      processor.setContent(view, content, modifier)
+      processor.setContent(view, content)
     }
 
     public fun unbind() {
       val view = this.view ?: return
 
       // Unbind the view.
-      processor.setContent(view, null, Modifier)
+      processor.setContent(view, null)
       this.view = null
 
       if (isPlaceholder) {
@@ -542,4 +537,9 @@ public abstract class LazyListUpdateProcessor<V : Any, W : Any> {
     class Move<W : Any>(val fromIndex: Int, val toIndex: Int, val count: Int) : Edit<W>()
     class Remove<W : Any>(var index: Int, var count: Int) : Edit<W>()
   }
+
+  private class SizeOnlyPlaceholderWidget<W : Any>(
+    override val value: W,
+    override var modifier: Modifier,
+  ) : Widget<W>
 }

redwood-lazylayout-widget/src/commonTest/kotlin/app/cash/redwood/lazylayout/widget/FakeUpdateProcessor.kt

@@ -15,9 +15,9 @@
  */
 package app.cash.redwood.lazylayout.widget
 
-import app.cash.redwood.Modifier
 import app.cash.redwood.lazylayout.widget.FakeUpdateProcessor.StringCell
 import app.cash.redwood.lazylayout.widget.FakeUpdateProcessor.StringContent
+import app.cash.redwood.widget.Widget
 
 /**
  * This fake simulates a real scroll window, which is completely independent of the window of loaded
@@ -112,7 +112,9 @@ class FakeUpdateProcessor : LazyListUpdateProcessor<StringCell, StringContent>()
     }
   }
 
-  override fun setContent(view: StringCell, content: StringContent?, modifier: Modifier) {
+  override fun setContent(view: StringCell, widget: Widget<StringContent>?) {
+    val content = widget?.value
+
     // It is an error for `content` to already have a parent cell.
     val previous = view.content
     require(content?.parentCell == null)

redwood-snapshot-testing/src/iosMain/kotlin/app/cash/redwood/snapshot/testing/UIViewTestWidgetFactory.kt

@@ -23,7 +23,6 @@ import app.cash.redwood.widget.ResizableWidget
 import app.cash.redwood.widget.ResizableWidget.SizeListener
 import kotlinx.cinterop.CValue
 import kotlinx.cinterop.readValue
-import platform.CoreGraphics.CGRectMake
 import platform.CoreGraphics.CGRectZero
 import platform.CoreGraphics.CGSize
 import platform.CoreGraphics.CGSizeMake
@@ -84,35 +83,34 @@ class UIViewText :
   }
 }
 
-class UIViewColor : Color<UIView> {
+class UIViewColor :
+  Color<UIView>,
+  ResizableWidget<UIView> {
+  override var sizeListener: SizeListener? = null
+
   override val value: UIView = object : UIView(CGRectZero.readValue()) {
-    override fun intrinsicContentSize(): CValue<CGSize> {
-      return CGSizeMake(width, height)
-    }
+    override fun intrinsicContentSize() = CGSizeMake(width, height)
+    override fun sizeThatFits(size: CValue<CGSize>) = CGSizeMake(width, height)
   }
+
   override var modifier: Modifier = Modifier
 
   private var width = 0.0
   private var height = 0.0
 
   override fun width(width: Dp) {
     this.width = with(Density.Default) { width.toPx() }
-    invalidate()
+    sizeListener?.invalidateSize()
   }
 
   override fun height(height: Dp) {
     this.height = with(Density.Default) { height.toPx() }
-    invalidate()
+    sizeListener?.invalidateSize()
   }
 
   override fun color(color: Int) {
     value.backgroundColor = color.toUIColor()
   }
-
-  private fun invalidate() {
-    value.setFrame(CGRectMake(0.0, 0.0, width, height))
-    value.invalidateIntrinsicContentSize()
-  }
 }
 
 class UIViewSimpleColumn : SimpleColumn<UIView> {