1 files changed, 54 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/shell/LogUtil.java b/src/main/java/com/google/devtools/build/lib/shell/LogUtil.java
new file mode 100644
index 0000000000..ab646f66ae
--- /dev/null
+++ b/src/main/java/com/google/devtools/build/lib/shell/LogUtil.java
@@ -0,0 +1,54 @@
+// Copyright 2014 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 com.google.devtools.build.lib.shell;
+
+/**
+ * Utilities for logging.
+ */
+class LogUtil {
+
+  private LogUtil() {}
+
+  private final static int TRUNCATE_STRINGS_AT = 150;
+
+  /**
+   * Make a string out of a byte array, and truncate it to a reasonable length.
+   * Useful for preventing logs from becoming excessively large.
+   */
+  static String toTruncatedString(final byte[] bytes) {
+    if(bytes == null || bytes.length == 0) {
+      return "";
+    }
+    /*
+     * Yes, we'll use the platform encoding here, and this is one of the rare
+     * cases where it makes sense. You want the logs to be encoded so that
+     * your platform tools (vi, emacs, cat) can render them, don't you?
+     * In practice, this means ISO-8859-1 or UTF-8, I guess.
+     */
+    try {
+      if (bytes.length > TRUNCATE_STRINGS_AT) {
+        return new String(bytes, 0, TRUNCATE_STRINGS_AT)
+          + "[... truncated. original size was " + bytes.length + " bytes.]";
+      }
+      return new String(bytes);
+    } catch (Exception e) {
+      /*
+       * In case encoding a binary string doesn't work for some reason, we
+       * don't want to bring a logging server down - do we? So we're paranoid.
+       */
+      return "IOUtil.toTruncatedString: " + e.getMessage();
+    }
+  }
+
+}