Clean up pub's exceptions.

sdk/lib/_internal/pub/lib/src/exceptions.dart

Index: sdk/lib/_internal/pub/lib/src/exceptions.dart
diff --git a/sdk/lib/_internal/pub/lib/src/exceptions.dart b/sdk/lib/_internal/pub/lib/src/exceptions.dart
new file mode 100644
index 0000000000000000000000000000000000000000..e7f4a28f02a571484d768a05c6ac827496f4e255
--- /dev/null
+++ b/sdk/lib/_internal/pub/lib/src/exceptions.dart
@@ -0,0 +1,105 @@
+// Copyright (c) 2014, 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 pub.exceptions;
+
+import 'dart:async';
+import 'dart:io';
+import 'dart:isolate';
+
+import "package:analyzer/analyzer.dart";
+import "package:http/http.dart" as http;
+import "package:stack_trace/stack_trace.dart";
+import "package:yaml/yaml.dart";
+
+import '../../asset/dart/serialize.dart';
+
+/// An exception class for exceptions that are intended to be seen by the user.
+///
+/// These exceptions won't have any debugging information printed when they're
+/// thrown.
+class ApplicationException implements Exception {
+  final String message;
+
+  ApplicationException(this.message);
+}
+
+/// A class for exceptions that wrap other exceptions.
+class WrappedException extends ApplicationException {
+  /// The underlying exception that [this] is wrapping, if any.
+  final innerError;
+
+  /// The stack chain for [innerError] if it exists.
+  final Chain innerChain;
+
+  WrappedException(String message, this.innerError, [StackTrace innerTrace])
+      : innerChain = innerTrace == null ? null : new Chain.forTrace(innerTrace),
+        super(message);
+}
+
+/// A class for command usage exceptions.
+class UsageException extends ApplicationException {
+  /// The command usage information.
+  final String usage;
+
+  UsageException(String message, this.usage)
+      : super(message);
+
+  String toString() => "$message\n\n$usage";
+}
+
+/// A class for errors in a command's input data.
+///
+/// This corresponds to the [exit_codes.DATA] exit code.
+class DataException extends ApplicationException {
+  DataException(String message)
+      : super(message);
+}
+
+/// An class for exceptions where a package could not be found in a [Source].
+///
+/// The source is responsible for wrapping its internal exceptions in this so
+/// that other code in pub can use this to show a more detailed explanation of
+/// why the package was being requested.
+class PackageNotFoundException extends WrappedException {
+  PackageNotFoundException(String message, [innerError, StackTrace innerTrace])
+      : super(message, innerError, innerTrace);
+}
+
+/// All the names of user-facing exceptions.
+final _userFacingExceptions = new Set<String>.from([
+  'ApplicationException',
+  // This refers to http.ClientException.
+  'ClientException',
+  // Errors coming from the Dart analyzer are probably caused by syntax errors
+  // in user code, so they're user-facing.
+  'AnalyzerError', 'AnalyzerErrorGroup',
+  // An error spawning an isolate probably indicates a transformer with an
+  // invalid import.
+  'IsolateSpawnException',
+  // IOException and subclasses.
+  'CertificateException', 'FileSystemException', 'HandshakeException',
+  'HttpException', 'IOException', 'ProcessException', 'RedirectException',
+  'SignalException', 'SocketException', 'StdoutException', 'TlsException',
+  'WebSocketException'
+]);
+
+/// Returns whether [error] is a user-facing error object.
+///
+/// This includes both [ApplicationException] and any dart:io errors.
+bool isUserFacingException(error) {
+  if (error is CrossIsolateException) {
+    return _userFacingExceptions.contains(error.type);
+  }
+
+  // TODO(nweiz): unify this list with _userFacingExceptions when issue 5897 is
+  // fixed.
+  return error is ApplicationException ||
+    error is AnalyzerError ||
+    error is AnalyzerErrorGroup ||
+    error is IsolateSpawnException ||
+    error is IOException ||
+    error is http.ClientException ||
+    error is YamlException;
+}