Move kotlin to it's own file

kapt is going to make kotlin a little more complicated, move the
rules and tests to their own files.

Bug: 122251693
Test: m checkbuild
Change-Id: Ieed78b97995ced210b710bd50c357514cc8e3bc6
diff --git a/java/kotlin.go b/java/kotlin.go
new file mode 100644
index 0000000..5bc7441
--- /dev/null
+++ b/java/kotlin.go
@@ -0,0 +1,71 @@
+// Copyright 2019 Google Inc. All rights reserved.
+//
+// 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 java
+
+import (
+	"android/soong/android"
+	"strings"
+
+	"github.com/google/blueprint"
+)
+
+var kotlinc = pctx.AndroidGomaStaticRule("kotlinc",
+	blueprint.RuleParams{
+		Command: `rm -rf "$classesDir" "$srcJarDir" "$kotlinBuildFile" && mkdir -p "$classesDir" "$srcJarDir" && ` +
+			`${config.ZipSyncCmd} -d $srcJarDir -l $srcJarDir/list -f "*.java" $srcJars && ` +
+			`${config.GenKotlinBuildFileCmd} $classpath $classesDir $out.rsp $srcJarDir/list > $kotlinBuildFile &&` +
+			`${config.KotlincCmd} $kotlincFlags ` +
+			`-jvm-target $kotlinJvmTarget -Xbuild-file=$kotlinBuildFile && ` +
+			`${config.SoongZipCmd} -jar -o $out -C $classesDir -D $classesDir`,
+		CommandDeps: []string{
+			"${config.KotlincCmd}",
+			"${config.KotlinCompilerJar}",
+			"${config.GenKotlinBuildFileCmd}",
+			"${config.SoongZipCmd}",
+			"${config.ZipSyncCmd}",
+		},
+		Rspfile:        "$out.rsp",
+		RspfileContent: `$in`,
+	},
+	"kotlincFlags", "classpath", "srcJars", "srcJarDir", "classesDir", "kotlinJvmTarget", "kotlinBuildFile")
+
+func kotlinCompile(ctx android.ModuleContext, outputFile android.WritablePath,
+	srcFiles, srcJars android.Paths,
+	flags javaBuilderFlags) {
+
+	inputs := append(android.Paths(nil), srcFiles...)
+
+	var deps android.Paths
+	deps = append(deps, flags.kotlincClasspath...)
+	deps = append(deps, srcJars...)
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:        kotlinc,
+		Description: "kotlinc",
+		Output:      outputFile,
+		Inputs:      inputs,
+		Implicits:   deps,
+		Args: map[string]string{
+			"classpath":       flags.kotlincClasspath.FormJavaClassPath("-classpath"),
+			"kotlincFlags":    flags.kotlincFlags,
+			"srcJars":         strings.Join(srcJars.Strings(), " "),
+			"classesDir":      android.PathForModuleOut(ctx, "kotlinc", "classes").String(),
+			"srcJarDir":       android.PathForModuleOut(ctx, "kotlinc", "srcJars").String(),
+			"kotlinBuildFile": android.PathForModuleOut(ctx, "kotlinc-build.xml").String(),
+			// http://b/69160377 kotlinc only supports -jvm-target 1.6 and 1.8
+			"kotlinJvmTarget": "1.8",
+		},
+	})
+}