1 files changed, 156 insertions, 0 deletions
diff --git a/src/main/java/com/google/devtools/build/lib/util/io/AnsiTerminalPrinter.java b/src/main/java/com/google/devtools/build/lib/util/io/AnsiTerminalPrinter.java
new file mode 100644
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@@ -0,0 +1,156 @@
+// 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.util.io;
+
+import com.google.devtools.build.lib.concurrent.ThreadSafety.ThreadCompatible;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintWriter;
+import java.util.EnumSet;
+import java.util.logging.Logger;
+import java.util.regex.Pattern;
+
+/**
+ * Allows to print "colored" strings by parsing predefined string keywords,
+ * which, depending on the useColor value are either replaced with ANSI terminal
+ * coloring sequences (as defined by the {@link AnsiTerminal} class) or stripped.
+ *
+ * Supported keywords are defined by the enum {@link AnsiTerminalPrinter.Mode}.
+ * Following keywords are supported:
+ *   INFO  - switches color to green.
+ *   ERROR - switches color to bold red.
+ *   WARNING - switches color to magenta.
+ *   NORMAL - resets terminal to the default state.
+ *
+ * Each keyword is starts with prefix "{#" followed by the enum constant name
+ * and suffix "#}". Keywords should not be inserted manually - provided enum
+ * constants should be used instead.
+ */
+@ThreadCompatible
+public class AnsiTerminalPrinter {
+
+  private static final String MODE_PREFIX = "{#";
+  private static final String MODE_SUFFIX = "#}";
+
+  // Mode pattern must match MODE_PREFIX and do lookahead for the rest of the
+  // mode string.
+  private static final String MODE_PATTERN = "\\{\\#(?=[A-Z]+\\#\\})";
+
+  /**
+   * List of supported coloring modes for the {@link AnsiTerminalPrinter}.
+   */
+  public static enum Mode {
+    INFO,     // green
+    ERROR,    // bold red
+    WARNING,  // magenta
+    DEFAULT;  // default color
+
+    @Override
+    public String toString() {
+      return MODE_PREFIX + name() + MODE_SUFFIX;
+    }
+  }
+
+  private static final Logger LOG = Logger.getLogger(AnsiTerminalPrinter.class.getName());
+  private static final EnumSet<Mode> MODES = EnumSet.allOf(Mode.class);
+  private static final Pattern PATTERN = Pattern.compile(MODE_PATTERN);
+
+  private final OutputStream stream;
+  private final PrintWriter writer;
+  private final AnsiTerminal terminal;
+  private boolean useColor;
+  private Mode lastMode = Mode.DEFAULT;
+
+  /**
+   * Creates new instance using provided OutputStream and sets coloring logic
+   * for that instance.
+   */
+  public AnsiTerminalPrinter(OutputStream out, boolean useColor) {
+    this.useColor = useColor;
+    terminal = new AnsiTerminal(out);
+    writer = new PrintWriter(out, true);
+    stream = out;
+  }
+
+  /**
+   * Writes the specified string to the output stream while injecting coloring
+   * sequences when appropriate mode keyword is found and flushes.
+   *
+   * List of supported mode keywords is defined by the enum {@link Mode}.
+   *
+   * See class documentation for details.
+   */
+  public void print(String str) {
+    for (String part : PATTERN.split(str)) {
+      int index = part.indexOf(MODE_SUFFIX);
+      // Mode name will contain at least one character, so suffix index
+      // must be at least 1. If it isn't then there is no match.
+      if (index > 1) {
+        for (Mode mode : MODES) {
+          if (index == mode.name().length() && part.startsWith(mode.name())) {
+            setupTerminal(mode);
+            part = part.substring(index + MODE_SUFFIX.length());
+            break;
+          }
+        }
+      }
+      writer.print(part);
+      writer.flush();
+    }
+  }
+
+  public void printLn(String str) {
+    print(str + "\n");
+  }
+
+  /**
+   * Returns the underlying OutputStream.
+   */
+  public OutputStream getOutputStream() {
+    return stream;
+  }
+
+  /**
+   * Injects coloring escape sequences if output should be colored and mode
+   * has been changed.
+   */
+  private void setupTerminal(Mode mode) {
+    if (!useColor) {
+      return;
+    }
+    try {
+      if (lastMode != mode) {
+        terminal.resetTerminal();
+        lastMode = mode;
+        if (mode == Mode.DEFAULT) {
+          return; // Terminal is already reset - nothing else to do.
+        } else if (mode == Mode.INFO) {
+          terminal.textGreen();
+        } else if (mode == Mode.ERROR) {
+          terminal.textRed();
+          terminal.textBold();
+        } else if (mode == Mode.WARNING) {
+          terminal.textMagenta();
+        }
+      }
+    } catch (IOException e) {
+      // AnsiTerminal state is now considered to be inconsistent - coloring
+      // should be disabled to prevent future use of AnsiTerminal instance.
+      LOG.warning("Disabling coloring due to " + e.getMessage());
+      useColor = false;
+    }
+  }
+}