Merge pull request #68 from cheonjaeung/refactor-grid-span

Rafactor internal span handling code of horizontal, vertical grid

Author: cheonjaeung

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/GridScope.kt

@@ -5,6 +5,7 @@ import androidx.compose.runtime.Immutable
 import androidx.compose.runtime.Stable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.platform.debugInspectorInfo
 
 /**
  * A Scope for the children of [HorizontalGrid] or [VerticalGrid].
@@ -32,7 +33,11 @@ internal object GridScopeInstance : GridScope {
     override fun Modifier.span(span: (GridItemSpanScope.() -> Int)?): Modifier {
         return this.then(
             HorizontalVerticalGridSpanElement(
-                span ?: HorizontalVerticalGridParentData.DefaultSpan
+                span = span,
+                inspectorInfo = debugInspectorInfo {
+                    name = "span"
+                    value = span
+                }
             )
         )
     }

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/HorizontalVerticalGridMeasurePolicy.kt

@@ -118,9 +118,6 @@ private class HorizontalVerticalGridMeasureHelper(
         measurables[it].parentData as? HorizontalVerticalGridParentData
     }
 
-    private val HorizontalVerticalGridParentData?.spanOrDefault: (GridItemSpanScope.() -> Int)
-        get() = this?.span ?: HorizontalVerticalGridParentData.DefaultSpan
-
     /**
      * Measures children composable constraints.
      */
@@ -158,9 +155,14 @@ private class HorizontalVerticalGridMeasureHelper(
                     maxCurrentLineSpan = maxSpan - spanSum,
                     maxLineSpan = maxSpan
                 )
-                val scopeFunction = gridParentDataArrays[measurableIndex].spanOrDefault
-                val span = scopeFunction(spanScope)
+                val spanFunction = gridParentDataArrays[measurableIndex]?.span
+                val span = if (spanFunction != null) {
+                    with(spanScope) { spanFunction() }
+                } else {
+                    1
+                }
                 require(span > 0) { "span must be bigger than zero, $span is zero or negative" }
+
                 if (span > maxSpan) {
                     measurableIndex++
                     continue

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/HorizontalVerticalGridParentData.kt

@@ -6,11 +6,10 @@ import androidx.compose.ui.Alignment
  * A data class to contain modifier options of item at the specified position.
  */
 internal data class HorizontalVerticalGridParentData(
-    var span: GridItemSpanScope.() -> Int = DefaultSpan,
+    var span: (GridItemSpanScope.() -> Int)? = null,
     var alignment: Alignment = DefaultAlignment
 ) {
     companion object {
-        internal val DefaultSpan: GridItemSpanScope.() -> Int = { 1 }
         internal val DefaultAlignment: Alignment = Alignment.TopStart
     }
 }

grid/src/commonMain/kotlin/com/cheonjaeung/compose/grid/HorizontalVerticalGridSpanModifier.kt

@@ -7,7 +7,8 @@ import androidx.compose.ui.platform.InspectorInfo
 import androidx.compose.ui.unit.Density
 
 internal class HorizontalVerticalGridSpanElement(
-    val span: GridItemSpanScope.() -> Int
+    val span: (GridItemSpanScope.() -> Int)?,
+    val inspectorInfo: InspectorInfo.() -> Unit
 ) : ModifierNodeElement<HorizontalVerticalGridSpanNode>() {
     override fun create(): HorizontalVerticalGridSpanNode {
         return HorizontalVerticalGridSpanNode(span)
@@ -18,8 +19,7 @@ internal class HorizontalVerticalGridSpanElement(
     }
 
     override fun InspectorInfo.inspectableProperties() {
-        name = "span"
-        value = span
+        inspectorInfo()
     }
 
     override fun equals(other: Any?): Boolean {
@@ -35,11 +35,11 @@ internal class HorizontalVerticalGridSpanElement(
 }
 
 internal class HorizontalVerticalGridSpanNode(
-    var span: GridItemSpanScope.() -> Int
+    var span: (GridItemSpanScope.() -> Int)?
 ) : Modifier.Node(), ParentDataModifierNode {
     override fun Density.modifyParentData(parentData: Any?): Any {
         val p = parentData as? HorizontalVerticalGridParentData ?: HorizontalVerticalGridParentData()
-        if (p.span == HorizontalVerticalGridParentData.DefaultSpan) {
+        if (p.span == null) {
             p.span = span
         }
         return p