improve analysis server notifications

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 1bc01d584eacc2664d559b8d0b8db4b6433931e7..c419055030f22bc7e7b49fccb1992b38daf21e04 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -24,6 +24,11 @@ class AnalysisServer {
   static const String ERROR_NOTIFICATION_NAME = 'context.errors';
 
   /**
+   * The name of the notification sent when analysis is complete.
+   */
+  static const String ANALYSIS_COMPLETE = "analysis.complete";
+
+  /**
    * The name of the contextId parameter.
    */
   static const String CONTEXT_ID_PARAM = 'contextId';
@@ -68,6 +73,11 @@ class AnalysisServer {
   final Map<String, AnalysisContext> contextMap = new Map<String, AnalysisContext>();
 
   /**
+   * A table mapping analysis contexts to the context id's associated with them.
+   */
+  final Map<AnalysisContext, String> contextIdMap = new Map<AnalysisContext, String>();
+
+  /**
    * A list of the analysis contexts for which analysis work needs to be
    * performed.
    *
@@ -162,8 +172,10 @@ class AnalysisServer {
     // Look for a context that has work to be done and then perform one task.
     //
     List<ChangeNotice> notices = null;
+    String contextId;
     try {
       AnalysisContext context = contextWorkQueue[0];
+      contextId = contextIdMap[context];
       AnalysisResult result = context.performAnalysisTask();
       notices = result.changeNotices;
     } finally {
@@ -172,7 +184,10 @@ class AnalysisServer {
         // unhandled exception trying to perform the analysis.  In either case,
         // remove the context form the work queue so we won't try to do more
         // analysis on it.
-        contextWorkQueue.removeAt(0);
+        AnalysisContext context = contextWorkQueue.removeAt(0);
+        var notification = new Notification(ANALYSIS_COMPLETE);

[Paul Berry, 2014/05/20 15:34:58]

I'm concerned that this is going to lead to bugs, because it provides no way for
the client to reliably know when analysis has started, so it's going to have to
guess.  If it fails to guess that analysis has started when it actually has, the
user will see no indication that analysis is going on.  If it falsely guesses
that analysis has started when it actually hasn't, it will appear to the user
that analysis is stuck in an infinite loop.

Also, based on features present in other refactoring editors, I suspect we're
eventually going to want to also communicate information like:

- What file is currently being analyzed
- Analysis progress (e.g. we have analyzed N files out of M)
- Estimated time until analysis completes

I would rather see an "analysis status" notification, containing this sort of
information in a map.  Initially we can just populate the map with a single
boolean to indicate whether analysis is in progress or not, and later we can add
other fields.

+        notification.setParameter(CONTEXT_ID_PARAM, contextId);
+        sendNotification(notification);
       }
       //
       // Schedule this method to be run again if there is any more work to be
@@ -183,17 +198,18 @@ class AnalysisServer {
       }
     }
     if (notices != null) {
-      sendNotices(notices);
+      sendNotices(contextId, notices);
     }
   }
 
   /**
    * Send the information in the given list of notices back to the client.
    */
-  void sendNotices(List<ChangeNotice> notices) {
+  void sendNotices(String contextId, List<ChangeNotice> notices) {
     for (int i = 0; i < notices.length; i++) {
       ChangeNotice notice = notices[i];
       Notification notification = new Notification(ERROR_NOTIFICATION_NAME);
+      notification.setParameter(CONTEXT_ID_PARAM, contextId);
       notification.setParameter(SOURCE_PARAM, notice.source.encoding);
       notification.setParameter(ERRORS_PARAM, notice.errors.map(
           errorToJson).toList());