[worker] Move WorkerProtocolImpl into its own package

Splitting it out of the main worker package makes re-using the code
for other implementations for dispatching requests to workers (e.g.,
for remote persistent workers, bazelbuild#10091) easier.

src/main/java/com/google/devtools/build/lib/worker/BUILD

@@ -21,7 +21,6 @@ java_library(
         ],
     ),
     deps = [
-        # ":worker_spawn_runner",
         "//third_party:guava",
         "//third_party/protobuf:protobuf_java",
         "//third_party/protobuf:protobuf_java_util",
@@ -35,6 +34,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/util:resource_converter",
         "//src/main/java/com/google/devtools/build/lib/vfs",
         "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
+        "//src/main/java/com/google/devtools/build/lib/worker/runner",
         "//src/main/java/com/google/devtools/common/options",
         "//src/main/protobuf:failure_details_java_proto",
         "//src/main/protobuf:worker_protocol_java_proto",

src/main/java/com/google/devtools/build/lib/worker/SingleplexWorker.java

@@ -23,6 +23,9 @@
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkRequest;
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkResponse;
+import com.google.devtools.build.lib.worker.runner.JsonWorkerProtocol;
+import com.google.devtools.build.lib.worker.runner.ProtoWorkerProtocol;
+import com.google.devtools.build.lib.worker.runner.WorkerProtocolImpl;
 import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;

src/main/java/com/google/devtools/build/lib/worker/WorkerMultiplexer.java

@@ -29,6 +29,9 @@
 import com.google.devtools.build.lib.vfs.PathFragment;
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkRequest;
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkResponse;
+import com.google.devtools.build.lib.worker.runner.JsonWorkerProtocol;
+import com.google.devtools.build.lib.worker.runner.ProtoWorkerProtocol;
+import com.google.devtools.build.lib.worker.runner.WorkerProtocolImpl;
 import java.io.File;
 import java.io.IOException;
 import java.io.InterruptedIOException;

src/main/java/com/google/devtools/build/lib/worker/runner/BUILD

@@ -0,0 +1,19 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
+package(default_visibility = ["//src:__subpackages__"])
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+    visibility = ["//src:__subpackages__"],
+)
+
+java_library(
+    name = "runner",
+    srcs = glob(["*.java"]),
+    deps = [
+        "//third_party/protobuf:protobuf_java_util",
+        "//src/main/protobuf:worker_protocol_java_proto",
+        "//third_party:gson",
+    ],
+)

src/main/java/com/google/devtools/build/lib/worker/JsonWorkerProtocol.java → src/main/java/com/google/devtools/build/lib/worker/runner/JsonWorkerProtocol.java

@@ -11,7 +11,7 @@
 // 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 com.google.devtools.build.lib.worker;
+package com.google.devtools.build.lib.worker.runner;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 
@@ -31,15 +31,15 @@
 import java.io.OutputStreamWriter;
 
 /** An implementation of a Bazel worker using JSON to communicate with the worker process. */
-final class JsonWorkerProtocol implements WorkerProtocolImpl {
+public final class JsonWorkerProtocol implements WorkerProtocolImpl {
   /** Reader for reading the WorkResponse. */
   private final JsonReader reader;
   /** Printer for printing the WorkRequest */
   private final Printer jsonPrinter;
   /** Writer for writing the WorkRequest to the worker */
   private final BufferedWriter jsonWriter;
 
-  JsonWorkerProtocol(OutputStream workersStdin, InputStream workersStdout) {
+  public JsonWorkerProtocol(OutputStream workersStdin, InputStream workersStdout) {
     jsonPrinter = JsonFormat.printer().omittingInsignificantWhitespace();
     jsonWriter = new BufferedWriter(new OutputStreamWriter(workersStdin, UTF_8));
     reader = new JsonReader(new BufferedReader(new InputStreamReader(workersStdout, UTF_8)));

src/main/java/com/google/devtools/build/lib/worker/ProtoWorkerProtocol.java → src/main/java/com/google/devtools/build/lib/worker/runner/ProtoWorkerProtocol.java

@@ -11,7 +11,7 @@
 // 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 com.google.devtools.build.lib.worker;
+package com.google.devtools.build.lib.worker.runner;
 
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkRequest;
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkResponse;
@@ -20,7 +20,7 @@
 import java.io.OutputStream;
 
 /** An implementation of a Bazel worker using Proto to communicate with the worker process. */
-final class ProtoWorkerProtocol implements WorkerProtocolImpl {
+public final class ProtoWorkerProtocol implements WorkerProtocolImpl {
 
   /** The worker process's stdin, which we send requests to. */
   private final OutputStream workersStdin;

src/main/java/com/google/devtools/build/lib/worker/WorkerProtocolImpl.java → src/main/java/com/google/devtools/build/lib/worker/runner/WorkerProtocolImpl.java

@@ -11,15 +11,15 @@
 // 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 com.google.devtools.build.lib.worker;
+package com.google.devtools.build.lib.worker.runner;
 
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkRequest;
 import com.google.devtools.build.lib.worker.WorkerProtocol.WorkResponse;
 import java.io.Closeable;
 import java.io.IOException;
 
 /** Represents the communication between Bazel and a persistent worker. */
-interface WorkerProtocolImpl extends Closeable {
+public interface WorkerProtocolImpl extends Closeable {
   /** Writes the provided work request to the worker. */
   void putRequest(WorkRequest request) throws IOException;