Rework requests in execution domain

pkg/analysis_server/lib/src/domain_execution.dart

 // 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 domain.execution;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/protocol.dart';
+import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * Instances of the class [ExecutionDomainHandler] implement a [RequestHandler]
  * that handles requests in the `execution` domain.
  */
 class ExecutionDomainHandler implements RequestHandler {
   /**
    * The analysis server that is using this handler to process requests.
@@ skipping 68 matching lines @@
         new ExecutionMapUriParams.fromRequest(request);
     String contextId = params.id;
     String path = contextMap[contextId];
     if (path == null) {
       return new Response.invalidParameter(
           request,
           'id',
           'There is no execution context with an id of $contextId');
     }
     AnalysisContext context = server.getAnalysisContext(path);
-    if (params.file != null) {
-      if (params.uri != null) {
+    if (context == null) {
+      return new Response.invalidExecutionContext(request, contextId);
+    }
+    String file = params.file;
+    String uri = params.uri;
+    if (file != null) {
+      if (uri != null) {
         return new Response.invalidParameter(
             request,
             'file',
             'Either file or uri must be provided, but not both');
       }
-      Source source = server.getSource(params.file);
-      String uri = context.sourceFactory.restoreUri(source).toString();
+      Resource resource = server.resourceProvider.getResource(file);
+      if (!resource.exists) {
+        return new Response.invalidParameter(request, 'file', 'The file must exist');
+      } else if (resource is! File) {
+        return new Response.invalidParameter(request, 'file', 'The file must be a file');

[Paul Berry, 2015/02/06 03:55:33]

This seems like a confusing error message.  Considering that the message will be
appended to "Invalid parameter 'file'", How about simply saying "Must not refer
to a directory"?

[Brian Wilkerson, 2015/02/06 15:49:00]

Done

+      }
+      Source source = server.getSource(file);
+      uri = context.sourceFactory.restoreUri(source).toString();
       return new ExecutionMapUriResult(uri: uri).toResponse(request.id);
-    } else if (params.uri != null) {
-      Source source = context.sourceFactory.forUri(params.uri);
-      String file = source.fullName;
+    } else if (uri != null) {
+      Source source = context.sourceFactory.forUri(uri);
+      if (source == null) {
+        return new Response.invalidParameter(
+            request,
+            'uri',
+            'The uri must be a valid URI');

[Paul Berry, 2015/02/06 03:55:33]

Similarly, this will be formatted as "Invalid parameter 'uri'.  The uri must be
a valid URI'", which I think people will find redundant :)

How about simply "Invalid URI"?

[Brian Wilkerson, 2015/02/06 15:49:00]

Done

+      }
+      file = source.fullName;
       return new ExecutionMapUriResult(file: file).toResponse(request.id);
     }
     return new Response.invalidParameter(
         request,
         'file',
         'Either file or uri must be provided');
   }
 
   /**
    * Implement the 'execution.setSubscriptions' request.
@@ skipping 92 matching lines @@
     if (_isInAnalysisRoot(filePath)) {
       server.sendNotification(
           new ExecutionLaunchDataParams(filePath, kind: kind).toNotification());
     }
   }
 
   static List<String> _getFullNames(List<Source> sources) {
     return sources.map((Source source) => source.fullName).toList();
   }
 }