gradle-plugin: Fix incremental build

The patch makes the plugin to set default input directories
(src/main/kotlin and src/main/c_interop) at task construction
rather than setting them during compiler command line building.
It allows gradle to perform up-to-date checks correctly.

tools/kotlin-native-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KonanCompileTask.kt

@@ -160,11 +160,7 @@ open class KonanCompileTask: KonanTargetableTask() {
         addKey("-opt", enableOptimization)
         addKey("-ea", enableAssertions)
 
-        (if (inputFiles.isEmpty()) {
+        inputFiles.flatMap { it.files }.filter { it.name.endsWith(".kt") }.mapTo(this) { it.canonicalPath }
-            project.fileTree("${project.projectDir.canonicalPath}/src/main/kotlin")
-        } else {
-            inputFiles.flatMap { it.files }
-        }).filter { it.name.endsWith(".kt") }.mapTo(this) { it.canonicalPath }
     }
 
     @TaskAction

tools/kotlin-native-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KonanInteropTask.kt

@@ -58,8 +58,6 @@ open class KonanInteropTask: KonanTargetableTask() {
         get() = listOf("-Dkonan.home=${project.konanHome}", "-Djava.library.path=${project.konanHome}/konan/nativelib")
     internal val INTEROP_CLASSPATH: String
         get() = "${project.konanHome}/konan/lib/"
-    internal val C_INTEROP_DIR_PATH: String
-        get() = "${project.projectDir}/src/main/c_interop"
 
     // Output directories -----------------------------------------------------
 
@@ -124,9 +122,7 @@ open class KonanInteropTask: KonanTargetableTask() {
         manifest ?.let {addArg("-manifest", it)}
 
         addArgIfNotNull("-target", target)
-        val defFilePath = defFile?.canonicalPath ?:
+        addArgIfNotNull("-def", defFile?.canonicalPath)
-                project.file("$C_INTEROP_DIR_PATH/$libName.def").takeIf { it.exists() }?.canonicalPath
-        addArgIfNotNull("-def", defFilePath)
         addArg("-pkg", pkg ?: libName)
         addArgIfNotNull("-linker", linker)
 
@@ -159,8 +155,8 @@ open class KonanInteropConfig(
     // Task to process the library and generate stubs
     val generateStubsTask: KonanInteropTask = project.tasks.create(
             "gen${name.capitalize()}InteropStubs",
-            KonanInteropTask::class.java
+            KonanInteropTask::class.java) {
-    ) { it.init(name) 
+        it.init(name)
         it.manifest = "${it.stubsDir.path}/manifest.properties"
     }
     // Config and task to compile *.kt stubs into a library

tools/kotlin-native-gradle-plugin/src/main/kotlin/org/jetbrains/kotlin/gradle/plugin/KonanPlugin.kt

@@ -48,6 +48,10 @@ internal val Project.konanInteropStubsOutputDir   get() = "${konanBuildRoot}/int
 internal val Project.konanInteropCompiledStubsDir get() = "${konanBuildRoot}/interopCompiledStubs"
 internal val Project.konanInteropLibsOutputDir    get() = "${konanBuildRoot}/nativelibs"
 
+internal val Project.konanDefaultSrcDir           get() = file("${projectDir.canonicalPath}/src/main/kotlin")
+internal fun Project.konanDefaultDefFile(interopName: String)
+        = file("${projectDir.canonicalPath}/src/main/c_interop/$interopName.def")
+
 internal val Project.konanArtifactsContainer: KonanArtifactsContainer
     get() = extensions.getByName(KonanPlugin.COMPILER_EXTENSION_NAME) as KonanArtifactsContainer
 internal val Project.konanInteropContainer: KonanInteropContainer
@@ -90,7 +94,11 @@ class KonanArtifactsContainer(val project: ProjectInternal): AbstractNamedDomain
         project.gradle.services.get(Instantiator::class.java)) {
 
     override fun doCreate(name: String): KonanCompileConfig =
-            KonanCompileConfig(name, project)
+            KonanCompileConfig(name, project).apply {
+                project.konanDefaultSrcDir?.takeIf { it.exists() }?.let {
+                    inputDir(it.canonicalPath)
+                }
+            }
 }
 
 class KonanInteropContainer(val project: ProjectInternal): AbstractNamedDomainObjectContainer<KonanInteropConfig>(
@@ -98,7 +106,11 @@ class KonanInteropContainer(val project: ProjectInternal): AbstractNamedDomainOb
         project.gradle.services.get(Instantiator::class.java)) {
 
     override fun doCreate(name: String): KonanInteropConfig =
-            KonanInteropConfig(name, project)
+            KonanInteropConfig(name, project).apply {
+                project.konanDefaultDefFile(name).takeIf { it.exists() }?.let {
+                    defFile(it.canonicalFile)
+                }
+            }
 }
 
 // Useful extensions and functions ---------------------------------------