Add observatory_pub_packages snapshot to third_party

observatory_pub_packages/csslib/src/messages.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+library csslib.src.messages;
+
+import 'package:logging/logging.dart' show Level;
+import 'package:source_span/source_span.dart';
+
+import 'options.dart';
+
+// TODO(terry): Remove the global messages, use some object that tracks
+//              compilation state.
+
+/** The global [Messages] for tracking info/warnings/messages. */
+Messages messages;
+
+// Color constants used for generating messages.
+final String GREEN_COLOR = '\u001b[32m';
+final String RED_COLOR = '\u001b[31m';
+final String MAGENTA_COLOR = '\u001b[35m';
+final String NO_COLOR = '\u001b[0m';
+
+/** Map between error levels and their display color. */
+final Map<Level, String> _ERROR_COLORS = (() {
+  var colorsMap = new Map<Level, String>();
+  colorsMap[Level.SEVERE] = RED_COLOR;
+  colorsMap[Level.WARNING] = MAGENTA_COLOR;
+  colorsMap[Level.INFO] = GREEN_COLOR;
+  return colorsMap;
+})();
+
+/** Map between error levels and their friendly name. */
+final Map<Level, String> _ERROR_LABEL = (() {
+  var labels = new Map<Level, String>();
+  labels[Level.SEVERE] = 'error';
+  labels[Level.WARNING] = 'warning';
+  labels[Level.INFO] = 'info';
+  return labels;
+})();
+
+/** A single message from the compiler. */
+class Message {
+  final Level level;
+  final String message;
+  final SourceSpan span;
+  final bool useColors;
+
+  Message(this.level, this.message, {SourceSpan span, bool useColors: false})
+      : this.span = span, this.useColors = useColors;
+
+  String toString() {
+    var output = new StringBuffer();
+    bool colors = useColors && _ERROR_COLORS.containsKey(level);
+    var levelColor = colors ? _ERROR_COLORS[level] : null;
+    if (colors) output.write(levelColor);
+    output..write(_ERROR_LABEL[level])..write(' ');
+    if (colors) output.write(NO_COLOR);
+
+    if (span == null) {
+      output.write(message);
+    } else {
+      output.write('on ');
+      output.write(span.message(message, color: levelColor));
+    }
+
+    return output.toString();
+  }
+}
+
+typedef void PrintHandler(Message obj);
+
+/**
+ * This class tracks and prints information, warnings, and errors emitted by the
+ * compiler.
+ */
+class Messages {
+  /** Called on every error. Set to blank function to supress printing. */
+  final PrintHandler printHandler;
+
+  final PreprocessorOptions options;
+
+  final List<Message> messages = <Message>[];
+
+  Messages({PreprocessorOptions options, this.printHandler: print})
+      : options = options != null ? options : new PreprocessorOptions();
+
+  /** Report a compile-time CSS error. */
+  void error(String message, SourceSpan span) {
+    var msg = new Message(Level.SEVERE, message, span: span,
+        useColors: options.useColors);
+
+    messages.add(msg);
+
+    printHandler(msg);
+  }
+
+  /** Report a compile-time CSS warning. */
+  void warning(String message, SourceSpan span) {
+    if (options.warningsAsErrors) {
+      error(message, span);
+    } else {
+      var msg = new Message(Level.WARNING, message, span: span,
+          useColors: options.useColors);
+
+      messages.add(msg);
+    }
+  }
+
+  /** Report and informational message about what the compiler is doing. */
+  void info(String message, SourceSpan span) {
+    var msg = new Message(Level.INFO, message, span: span,
+        useColors: options.useColors);
+
+    messages.add(msg);
+
+    if (options.verbose) printHandler(msg);
+  }
+
+  /** Merge [newMessages] to this message lsit. */
+  void mergeMessages(Messages newMessages) {
+    messages.addAll(newMessages.messages);
+    newMessages.messages.where((message) =>
+        message.level.value == Level.SEVERE || options.verbose)
+        .forEach((message) { printHandler(message); });
+  }
+}