Refactor the API of cotent pool

Summary:
## Context

Now we have two interface methods, `createRecyclingPool` and `onCreateMountContentPool`, which is confusing and caused wrong usages. This diff is to remove one of which and make `onCreateMountContentPool` the single truth of providing content pool.

Reviewed By: adityasharat

Differential Revision: D60367366

fbshipit-source-id: 78e2a91c306edb2ec44f0eba7a925b9aa7447754

Author: Andrew Wang

litho-annotations/src/main/java/com/facebook/litho/annotations/OnCreateMountContentPool.java

@@ -23,6 +23,16 @@
  * The annotated method will be called to create a custom MountContentPool for this mount spec. If a
  * method with this annotation isn't provided, a DefaultMountContentPool will be used to recycle the
  * mount content of this mount spec, which is almost always sufficient.
+ *
+ * <p>For example:
+ *
+ * <pre><code>
+ *
+ *  {@literal @OnCreateMountContentPool}
+ *   static MountItemsPool.ItemPool OnCreateMountContentPool(int poolSizeOverride) {
+ *     return new MountItemsPool.ItemPool(poolSizeOverride);
+ *   }
+ * </code></pre>
  */
 @Retention(RetentionPolicy.SOURCE)
 public @interface OnCreateMountContentPool {}

litho-core/src/main/java/com/facebook/litho/HostComponent.java

@@ -46,13 +46,6 @@ protected HostComponent(
     mPoolingPolicy = poolingPolicy;
   }
 
-  @Override
-  public MountItemsPool.ItemPool onCreateMountContentPool() {
-    return new HostMountContentPool(
-        ComponentsConfiguration.hostComponentPoolSize,
-        mPoolingPolicy.canAcquireContent || mPoolingPolicy.canReleaseContent);
-  }
-
   @Override
   public PoolingPolicy getPoolingPolicy() {
     return mPoolingPolicy;
@@ -68,6 +61,12 @@ protected Object onCreateMountContent(Context c) {
     return new ComponentHost(c, mUnsafeModificationPolicy);
   }
 
+  @Override
+  public MountItemsPool.ItemPool onCreateMountContentPool(int poolSizeOverride) {
+    return new HostMountContentPool(
+        poolSizeOverride, mPoolingPolicy.canAcquireContent || mPoolingPolicy.canReleaseContent);
+  }
+
   @Override
   protected void onMount(
       final @Nullable ComponentContext c,
@@ -134,7 +133,7 @@ public boolean isEquivalentProps(@Nullable Component other, boolean shouldCompar
 
   @Override
   public int poolSize() {
-    return 45;
+    return ComponentsConfiguration.hostComponentPoolSize;
   }
 
   @Override

litho-core/src/main/java/com/facebook/litho/HostMountContentPool.kt

@@ -47,7 +47,7 @@ class HostMountContentPool(maxSize: Int, isEnabled: Boolean) : ItemPool {
       return false
     }
 
-    return pool?.release(item) ?: false
+    return pool.release(item)
   }
 
   override fun maybePreallocateContent(c: Context, contentAllocator: ContentAllocator<*>): Boolean =

litho-core/src/main/java/com/facebook/litho/MountSpecLithoRenderUnit.kt

@@ -76,10 +76,10 @@ private constructor(
     isShouldUpdateResultCached = false
   }
 
-  override fun createRecyclingPool(poolSizeOverride: Int): ItemPool? {
+  override fun onCreateMountContentPool(poolSizeOverride: Int): ItemPool? {
     return try {
       if (component is SpecGeneratedComponent) {
-        component.createRecyclingPool()
+        component.onCreateMountContentPool(poolSizeOverride)
       } else {
         null
       }

litho-core/src/main/java/com/facebook/litho/SpecGeneratedComponent.java

@@ -58,7 +58,6 @@ public abstract class SpecGeneratedComponent extends Component
         EventTriggerTarget,
         HasEventTrigger {
 
-  private static final int DEFAULT_MAX_PREALLOCATION = 3;
   private static final DynamicValue[] sEmptyArray = new DynamicValue[0];
 
   private final String mSimpleName;
@@ -817,12 +816,6 @@ public Class<?> getPoolableContentType() {
     return getClass();
   }
 
-  @Nullable
-  @Override
-  public MountItemsPool.ItemPool createRecyclingPool(int poolSize) {
-    return onCreateMountContentPool();
-  }
-
   /**
    * @return true if this component can be preallocated.
    */
@@ -835,8 +828,8 @@ public boolean canPreallocate() {
    * @return the MountContentPool that should be used to recycle mount content for this mount spec.
    */
   @Override
-  public MountItemsPool.ItemPool onCreateMountContentPool() {
-    return new MountItemsPool.DefaultItemPool(getPoolableContentType(), poolSize());
+  public MountItemsPool.ItemPool onCreateMountContentPool(int poolSizeOverride) {
+    return new MountItemsPool.DefaultItemPool(getPoolableContentType(), poolSizeOverride);
   }
 
   @ThreadSafe

litho-it/src/main/java/com/facebook/litho/widget/CrashingMountableSpec.kt

@@ -134,7 +134,10 @@ object CrashingMountableSpec {
 
   @JvmStatic
   @OnCreateMountContentPool
-  fun onCreateMountContentPool(@InjectProp lifecycle: LifecycleStep): MountItemsPool.ItemPool {
+  fun onCreateMountContentPool(
+      poolSize: Int,
+      @InjectProp lifecycle: LifecycleStep
+  ): MountItemsPool.ItemPool {
     if (lifecycle == LifecycleStep.ON_CREATE_MOUNT_CONTENT_POOL) {
       throw MountPhaseException(LifecycleStep.ON_CREATE_MOUNT_CONTENT_POOL)
     }

litho-it/src/main/java/com/facebook/litho/widget/MountSpecLifecycleTesterDrawableSpec.kt

@@ -115,7 +115,7 @@ object MountSpecLifecycleTesterDrawableSpec {
 
   @JvmStatic
   @OnCreateMountContentPool
-  fun onCreateMountContentPool(): MountItemsPool.ItemPool = TrackingMountContentPool(1)
+  fun onCreateMountContentPool(poolSize: Int): MountItemsPool.ItemPool = TrackingMountContentPool(1)
 
   @JvmStatic
   @UiThread

litho-it/src/main/java/com/facebook/litho/widget/MountSpecLifecycleTesterSpec.kt

@@ -122,7 +122,7 @@ object MountSpecLifecycleTesterSpec {
 
   @JvmStatic
   @OnCreateMountContentPool
-  fun onCreateMountContentPool(): MountItemsPool.ItemPool = TrackingMountContentPool(1)
+  fun onCreateMountContentPool(poolSize: Int): MountItemsPool.ItemPool = TrackingMountContentPool(1)
 
   @JvmStatic
   @UiThread

litho-it/src/main/java/com/facebook/litho/widget/MountSpecPureRenderLifecycleTesterSpec.kt

@@ -120,7 +120,7 @@ object MountSpecPureRenderLifecycleTesterSpec {
 
   @JvmStatic
   @OnCreateMountContentPool
-  fun onCreateMountContentPool(): MountItemsPool.ItemPool = TrackingMountContentPool(1)
+  fun onCreateMountContentPool(poolSize: Int): MountItemsPool.ItemPool = TrackingMountContentPool(1)
 
   @JvmStatic
   @UiThread

litho-it/src/main/java/com/facebook/litho/widget/PreallocatedMountSpecLifecycleTesterSpec.kt

@@ -85,7 +85,7 @@ object PreallocatedMountSpecLifecycleTesterSpec {
   @JvmStatic
   @UiThread
   @OnCreateMountContentPool
-  fun onCreateMountContentPool(): MountItemsPool.ItemPool = TrackingMountContentPool(1)
+  fun onCreateMountContentPool(poolSize: Int): MountItemsPool.ItemPool = TrackingMountContentPool(1)
 
   @JvmStatic
   @UiThread

litho-it/src/test/resources/processor/TestMount.java

@@ -477,9 +477,9 @@ public boolean implementsShouldUpdate() {
   }
 
   @Override
-  public MountItemsPool.ItemPool onCreateMountContentPool() {
+  public MountItemsPool.ItemPool onCreateMountContentPool(int size) {
     MountItemsPool.ItemPool _result;
-    _result = (MountItemsPool.ItemPool) TestMountSpec.onCreateMountContentPool();
+    _result = (MountItemsPool.ItemPool) TestMountSpec.onCreateMountContentPool(size);
     return _result;
   }
 

litho-it/src/test/resources/processor/TestMountSpec.java

@@ -216,8 +216,8 @@ static boolean shouldUpdate(@Prop Diff<Integer> prop1) {
   }
 
   @OnCreateMountContentPool
-  static MountItemsPool.ItemPool onCreateMountContentPool() {
-    return new MountItemsPool.DefaultItemPool(TestMountSpec.class, 3);
+  static MountItemsPool.ItemPool onCreateMountContentPool(int size) {
+    return new MountItemsPool.DefaultItemPool(TestMountSpec.class, size);
   }
 
   @OnCalculateCachedValue(name = "cached")

litho-processor/src/main/java/com/facebook/litho/specmodels/model/DelegateMethodDescriptions.java

@@ -258,7 +258,7 @@ public final class DelegateMethodDescriptions {
           .accessType(Modifier.PUBLIC)
           .returnType(ClassNames.MOUNT_CONTENT_POOL)
           .name("onCreateMountContentPool")
-          .definedParameterTypes(ImmutableList.<TypeName>of())
+          .definedParameterTypes(ImmutableList.<TypeName>of(TypeName.INT))
           .optionalParameterTypes(ImmutableList.of(INJECT_PROP))
           .build();
 

litho-rendercore/src/main/java/com/facebook/rendercore/ContentAllocator.kt

@@ -50,14 +50,6 @@ interface ContentAllocator<Content : Any> {
   val poolingPolicy: PoolingPolicy
     get() = PoolingPolicy.Default
 
-  fun createRecyclingPool(poolSizeOverride: Int = UNSET_POOL_SIZE): ItemPool? {
-    return if (poolSizeOverride > UNSET_POOL_SIZE) {
-      DefaultItemPool(javaClass, poolSizeOverride)
-    } else {
-      onCreateMountContentPool()
-    }
-  }
-
   /**
    * This API informs the framework to fill the content pool for this Mountable ahead of time. The
    * default value is `false`, i.e. content is not pre-allocated. Pre-allocation of the content can
@@ -71,7 +63,10 @@ interface ContentAllocator<Content : Any> {
   fun poolSize(): Int = DEFAULT_MAX_PREALLOCATION
 
   /** Creates the content pool the framework should use for this [ContentAllocator] */
-  fun onCreateMountContentPool(): ItemPool = DefaultItemPool(javaClass, poolSize())
+  fun onCreateMountContentPool(poolSizeOverride: Int = UNSET_POOL_SIZE): ItemPool? {
+    val size = if (poolSizeOverride > UNSET_POOL_SIZE) poolSizeOverride else poolSize()
+    return DefaultItemPool(javaClass, size)
+  }
 
   companion object {
     /** Default size of the content pool. */

litho-rendercore/src/main/java/com/facebook/rendercore/MountItemsPool.kt

@@ -203,7 +203,7 @@ object MountItemsPool {
 
       if (pool == null) {
         pool =
-            allocator.createRecyclingPool(poolSize)
+            allocator.onCreateMountContentPool(poolSize)
                 ?: DefaultItemPool(poolableContentType, poolSize)
       }