Add ResourceContentHash annotation to generated resource accessors.

Used by Compose Hot Reload to mark a related accessor as dirty if the hash is changed after reloading of new accessors.

Author: pjBooms

components/resources/library/src/commonMain/kotlin/org/jetbrains/compose/resources/ResourceContentHash.kt

@@ -0,0 +1,5 @@
+package org.jetbrains.compose.resources
+
+@Suppress("unused")
+@Retention(AnnotationRetention.BINARY)
+annotation class ResourceContentHash(val hash: Int)

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/resources/GenerateResourceAccessorsTask.kt

@@ -110,7 +110,8 @@ internal abstract class GenerateResourceAccessorsTask : IdeaImportTask() {
         }
 
         val type = ResourceType.fromString(typeString) ?: error("Unknown resource type: '$typeString'.")
-        return listOf(ResourceItem(type, qualifiers, file.nameWithoutExtension.asUnderscoredIdentifier(), path))
+        return listOf(ResourceItem(type, qualifiers, file.nameWithoutExtension.asUnderscoredIdentifier(), path,
+            file.readBytes().contentHashCode()))
     }
 
     private fun getValueResourceItems(dataFile: File, qualifiers: List<String>, path: Path): List<ResourceItem> {
@@ -141,7 +142,8 @@ internal abstract class GenerateResourceAccessorsTask : IdeaImportTask() {
         path: Path
     ): ResourceItem {
         val record = ValueResourceRecord.createFromString(recordString)
-        return ResourceItem(record.type, qualifiers, record.key.asUnderscoredIdentifier(), path, offset, size)
+        return ResourceItem(record.type, qualifiers, record.key.asUnderscoredIdentifier(), path,
+            record.content.hashCode(), offset, size)
     }
 }
 

gradle-plugins/compose/src/main/kotlin/org/jetbrains/compose/resources/GeneratedResClassSpec.kt

@@ -39,6 +39,7 @@ internal data class ResourceItem(
     val qualifiers: List<String>,
     val name: String,
     val path: Path,
+    val contentHash: Int,
     val offset: Long = -1,
     val size: Long = -1,
 )
@@ -58,6 +59,8 @@ private val resourceItemClass = ClassName("org.jetbrains.compose.resources", "Re
 private val internalAnnotationClass = ClassName("org.jetbrains.compose.resources", "InternalResourceApi")
 private val internalAnnotation = AnnotationSpec.builder(internalAnnotationClass).build()
 
+private val resourceContentHashAnnotationClass = ClassName("org.jetbrains.compose.resources", "ResourceContentHash")
+
 private fun CodeBlock.Builder.addQualifiers(resourceItem: ResourceItem): CodeBlock.Builder {
     val languageQualifier = ClassName("org.jetbrains.compose.resources", "LanguageQualifier")
     val regionQualifier = ClassName("org.jetbrains.compose.resources", "RegionQualifier")
@@ -283,7 +286,12 @@ private fun getChunkFileSpec(
                 .endControlFlow()
                 .build()
 
+            val resourceContentHashAnnotation = AnnotationSpec.builder(resourceContentHashAnnotationClass)
+                .useSiteTarget(AnnotationSpec.UseSiteTarget.DELEGATE)
+                .addMember("%L", items.fold(0){acc, item -> ((acc * 31) + item.contentHash)}).build()
+
             val accessor = PropertySpec.builder(resName, type.getClassName(), resModifier)
+                .addAnnotation(resourceContentHashAnnotation)
                 .receiver(ClassName(packageName, resClassName, type.accessorName))
                 .delegate(initializer)
                 .build()