Add a BuildEventTransport writing text-format protos

This will allow a precise, but still human-readable, transcript of the
build-event protocol buffers generated.

--
Change-Id: I6284521f652b04ab6bf54e5eeed7b92f2d7e2245
Reviewed-on: https://bazel-review.googlesource.com/#/c/6273
MOS_MIGRATED_REVID=134637366

2 files changed, 67 insertions, 0 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD
new file mode 100644
index 0000000000..618abca496
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/BUILD
@@ -0,0 +1,16 @@
+package(default_visibility = ["//src:__subpackages__"])
+
+filegroup(
+    name = "srcs",
+    srcs = glob(["**"]),
+)
+
+java_library(
+    name = "transports",
+    srcs = glob(["*.java"]),
+    deps = [
+        "//src/main/java/com/google/devtools/build/lib:buildeventstream",
+        "//src/main/java/com/google/devtools/build/lib/buildeventstream/proto:build_event_stream_java_proto",
+        "//third_party/protobuf",
+    ],
+)
diff --git a/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/TextFormatFileTransport.java b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/TextFormatFileTransport.java
new file mode 100644
index 0000000000..98b7520c33
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/buildeventstream/transports/TextFormatFileTransport.java
@@ -0,0 +1,51 @@
+// Copyright 2016 The Bazel Authors. 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 com.google.devtools.build.lib.buildeventstream.transports;
+
+import com.google.devtools.build.lib.buildeventstream.BuildEvent;
+import com.google.devtools.build.lib.buildeventstream.BuildEventTransport;
+import com.google.protobuf.TextFormat;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+
+/**
+ * A simple {@link BuildEventTransport} that writes the text representation of the protocol-buffer
+ * representation of the events to a file. This is mainly useful for debugging.
+ */
+public final class TextFormatFileTransport implements BuildEventTransport {
+  private FileOutputStream out;
+
+  public TextFormatFileTransport(String path) throws IOException {
+    this.out = new FileOutputStream(new File(path));
+  }
+
+  @Override
+  public synchronized void sendBuildEvent(BuildEvent event) throws IOException {
+    if (out != null) {
+      String protoTextRepresentation = TextFormat.printToString(event.asStreamProto());
+      out.write(("event {\n" + protoTextRepresentation + "}\n\n").getBytes(StandardCharsets.UTF_8));
+      out.flush();
+    }
+  }
+
+  @Override
+  public void close() throws IOException {
+    if (out != null) {
+      out.close();
+    }
+  }
+}