Re-copy the prefab headers when a header changes

packages/gradle-plugin/react-native-gradle-plugin/src/main/kotlin/com/facebook/react/tasks/internal/PreparePrefabHeadersTask.kt

@@ -12,10 +12,14 @@ import java.io.File
 import javax.inject.Inject
 import org.gradle.api.DefaultTask
 import org.gradle.api.file.DirectoryProperty
+import org.gradle.api.file.FileCollection
 import org.gradle.api.file.FileSystemOperations
+import org.gradle.api.file.FileTree
 import org.gradle.api.file.RegularFile
+import org.gradle.api.model.ObjectFactory
 import org.gradle.api.provider.ListProperty
 import org.gradle.api.tasks.Input
+import org.gradle.api.tasks.InputFiles
 import org.gradle.api.tasks.OutputDirectory
 import org.gradle.api.tasks.TaskAction
 
@@ -35,44 +39,64 @@ abstract class PreparePrefabHeadersTask : DefaultTask() {
 
   @get:OutputDirectory abstract val outputDir: DirectoryProperty
 
+  @get:InputFiles
+  val headers: FileCollection
+    get() =
+        objects
+            .fileCollection()
+            .from(
+                input.map { entries ->
+                  entries.flatMap { (_, pathToPrefixCouples) ->
+                    pathToPrefixCouples.map { (headerPath, _) -> headersUnder(headerPath) }
+                  }
+                }
+            )
+
   @get:Inject abstract val fs: FileSystemOperations
 
+  @get:Inject abstract val objects: ObjectFactory
+
   @TaskAction
   fun taskAction() {
     input.get().forEach { (libraryName, pathToPrefixCouples) ->
       val outputFolder: RegularFile = outputDir.file(libraryName).get()
+      fs.delete { deleteSpec -> deleteSpec.delete(outputFolder) }
       pathToPrefixCouples.forEach { (headerPath, headerPrefix) ->
         fs.copy { copySpec ->
-          copySpec.from(headerPath)
-          copySpec.include("**/*.h")
-          copySpec.exclude("**/*.cpp")
-          copySpec.exclude("**/*.txt")
-          // We don't want to copy all the boost headers as they are 250Mb+
-          copySpec.include("boost/config.hpp")
-          copySpec.include("boost/config/**/*.hpp")
-          copySpec.include("boost/core/*.hpp")
-          copySpec.include("boost/detail/workaround.hpp")
-          copySpec.include("boost/operators.hpp")
-          copySpec.include("boost/preprocessor/**/*.hpp")
-          // Headers needed for exposing rrc_text and rrc_textinput
-          copySpec.include("boost/container_hash/**/*.hpp")
-          copySpec.include("boost/detail/**/*.hpp")
-          copySpec.include("boost/intrusive/**/*.hpp")
-          copySpec.include("boost/iterator/**/*.hpp")
-          copySpec.include("boost/move/**/*.hpp")
-          copySpec.include("boost/mpl/**/*.hpp")
-          copySpec.include("boost/mp11/**/*.hpp")
-          copySpec.include("boost/describe/**/*.hpp")
-          copySpec.include("boost/type_traits/**/*.hpp")
-          copySpec.include("boost/utility/**/*.hpp")
-          copySpec.include("boost/assert.hpp")
-          copySpec.include("boost/static_assert.hpp")
-          copySpec.include("boost/cstdint.hpp")
-          copySpec.include("boost/utility.hpp")
-          copySpec.include("boost/version.hpp")
+          copySpec.from(headersUnder(headerPath))
           copySpec.into(File(outputFolder.asFile, headerPrefix))
         }
       }
     }
   }
+
+  private fun headersUnder(headerPath: String): FileTree =
+      objects.fileTree().from(headerPath).matching { patterns ->
+        patterns.include("**/*.h")
+        patterns.exclude("**/*.cpp")
+        patterns.exclude("**/*.txt")
+        // We don't want to copy all the boost headers as they are 250Mb+
+        patterns.include("boost/config.hpp")
+        patterns.include("boost/config/**/*.hpp")
+        patterns.include("boost/core/*.hpp")
+        patterns.include("boost/detail/workaround.hpp")
+        patterns.include("boost/operators.hpp")
+        patterns.include("boost/preprocessor/**/*.hpp")
+        // Headers needed for exposing rrc_text and rrc_textinput
+        patterns.include("boost/container_hash/**/*.hpp")
+        patterns.include("boost/detail/**/*.hpp")
+        patterns.include("boost/intrusive/**/*.hpp")
+        patterns.include("boost/iterator/**/*.hpp")
+        patterns.include("boost/move/**/*.hpp")
+        patterns.include("boost/mpl/**/*.hpp")
+        patterns.include("boost/mp11/**/*.hpp")
+        patterns.include("boost/describe/**/*.hpp")
+        patterns.include("boost/type_traits/**/*.hpp")
+        patterns.include("boost/utility/**/*.hpp")
+        patterns.include("boost/assert.hpp")
+        patterns.include("boost/static_assert.hpp")
+        patterns.include("boost/cstdint.hpp")
+        patterns.include("boost/utility.hpp")
+        patterns.include("boost/version.hpp")
+      }
 }

packages/gradle-plugin/react-native-gradle-plugin/src/test/kotlin/com/facebook/react/tasks/internal/PreparePrefabHeadersTaskTest.kt

@@ -204,6 +204,42 @@ class PreparePrefabHeadersTaskTest {
     assertThat(File(outputDir, "sample_library/boost/anothermodule/wedontuse.hpp")).doesNotExist()
   }
 
+  @Test
+  fun preparePrefabHeadersTask_declaresTheHeadersItCopiesAsInputs() {
+    val header = File(tempFolder.root, "input/hello.h").apply { createNewPathAndFile() }
+    File(tempFolder.root, "input/hello.cpp").createNewPathAndFile()
+
+    val project = createProject(projectDir = tempFolder.root)
+    val task =
+        createTestTask<PreparePrefabHeadersTask>(project = project) {
+          it.outputDir.set(tempFolder.newFolder("output"))
+          it.input.set(listOf(PrefabPreprocessingEntry("sample_library", "input/" to "")))
+        }
+
+    assertThat(task.inputs.files.files).containsExactly(header)
+  }
+
+  @Test
+  fun preparePrefabHeadersTask_withARemovedHeader_removesItsCopy() {
+    val outputDir = tempFolder.newFolder("output")
+    val removedHeader = File(tempFolder.root, "input/removed.h").apply { createNewPathAndFile() }
+    File(tempFolder.root, "input/kept.h").createNewPathAndFile()
+
+    val project = createProject(projectDir = tempFolder.root)
+    val task =
+        createTestTask<PreparePrefabHeadersTask>(project = project) {
+          it.outputDir.set(outputDir)
+          it.input.set(listOf(PrefabPreprocessingEntry("sample_library", "input/" to "")))
+        }
+
+    task.taskAction()
+    removedHeader.delete()
+    task.taskAction()
+
+    assertThat(File(outputDir, "sample_library/removed.h")).doesNotExist()
+    assertThat(File(outputDir, "sample_library/kept.h")).exists()
+  }
+
   private fun File.createNewPathAndFile() {
     parentFile.mkdirs()
     createNewFile()