Convert MeasureSpecUtils to Kotlin

Summary: as per title

Reviewed By: pengj

Differential Revision: D52999947

fbshipit-source-id: 061379ef6b43cc8df7910a2fbb0ed27f6b310a1d

litho-rendercore/src/main/java/com/facebook/rendercore/utils/MeasureSpecUtils.kt

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.facebook.rendercore.utils
+
+import android.view.View.MeasureSpec
+import java.util.Locale
+
+/**
+ * An utility class to verify that an old measured size is still compatible to be used with a new
+ * measureSpec.
+ */
+object MeasureSpecUtils {
+
+  private const val DELTA = 0.5f
+  private val UNSPECIFIED = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)
+
+  @JvmStatic fun unspecified(): Int = UNSPECIFIED
+
+  @JvmStatic fun atMost(px: Int): Int = MeasureSpec.makeMeasureSpec(px, MeasureSpec.AT_MOST)
+
+  @JvmStatic fun exactly(px: Int): Int = MeasureSpec.makeMeasureSpec(px, MeasureSpec.EXACTLY)
+
+  @JvmStatic fun getMode(spec: Int): Int = MeasureSpec.getMode(spec)
+
+  @JvmStatic fun getSize(spec: Int): Int = MeasureSpec.getSize(spec)
+
+  @JvmStatic
+  fun areMeasureSpecsEquivalent(specA: Int, specB: Int): Boolean =
+      specA == specB ||
+          (MeasureSpec.getMode(specA) == UNSPECIFIED && MeasureSpec.getMode(specB) == UNSPECIFIED)
+
+  @JvmStatic
+  fun isMeasureSpecCompatible(oldSizeSpec: Int, sizeSpec: Int, oldMeasuredSize: Int): Boolean {
+    val newSpecMode = MeasureSpec.getMode(sizeSpec)
+    val newSpecSize = MeasureSpec.getSize(sizeSpec)
+    val oldSpecMode = MeasureSpec.getMode(oldSizeSpec)
+    val oldSpecSize = MeasureSpec.getSize(oldSizeSpec)
+    return (oldSizeSpec == sizeSpec) ||
+        (oldSpecMode == UNSPECIFIED && newSpecMode == UNSPECIFIED) ||
+        newSizeIsExactAndMatchesOldMeasuredSize(
+            newSpecMode, newSpecSize, oldMeasuredSize.toFloat()) ||
+        oldSizeIsUnspecifiedAndStillFits(
+            oldSpecMode, newSpecMode, newSpecSize, oldMeasuredSize.toFloat()) ||
+        newMeasureSizeIsStricterAndStillValid(
+            oldSpecMode, newSpecMode, oldSpecSize, newSpecSize, oldMeasuredSize.toFloat())
+  }
+
+  private fun newSizeIsExactAndMatchesOldMeasuredSize(
+      newSizeSpecMode: Int,
+      newSizeSpecSize: Int,
+      oldMeasuredSize: Float
+  ): Boolean =
+      newSizeSpecMode == MeasureSpec.EXACTLY && Math.abs(newSizeSpecSize - oldMeasuredSize) < DELTA
+
+  private fun oldSizeIsUnspecifiedAndStillFits(
+      oldSizeSpecMode: Int,
+      newSizeSpecMode: Int,
+      newSizeSpecSize: Int,
+      oldMeasuredSize: Float
+  ): Boolean =
+      newSizeSpecMode == MeasureSpec.AT_MOST &&
+          oldSizeSpecMode == UNSPECIFIED &&
+          newSizeSpecSize >= oldMeasuredSize
+
+  private fun newMeasureSizeIsStricterAndStillValid(
+      oldSizeSpecMode: Int,
+      newSizeSpecMode: Int,
+      oldSizeSpecSize: Int,
+      newSizeSpecSize: Int,
+      oldMeasuredSize: Float
+  ): Boolean =
+      oldSizeSpecMode == MeasureSpec.AT_MOST &&
+          newSizeSpecMode == MeasureSpec.AT_MOST &&
+          oldSizeSpecSize > newSizeSpecSize &&
+          oldMeasuredSize <= newSizeSpecSize
+
+  @JvmStatic
+  fun getMeasureSpecDescription(measureSpec: Int): String {
+    val value = getSize(measureSpec)
+    val mode = getModeDescription(getMode(measureSpec))
+    return String.format(Locale.US, "[%d, %s]", value, mode)
+  }
+
+  @JvmStatic
+  fun getModeDescription(mode: Int): String =
+      when (mode) {
+        MeasureSpec.AT_MOST -> "AT_MOST"
+        MeasureSpec.EXACTLY -> "EXACTLY"
+        UNSPECIFIED -> "UNSPECIFIED"
+        else -> "INVALID"
+      }
+}