[geary/wip/713150-conversations: 9/9] Better filling of window, prevent soft assertions when chg folders/exiting

[Jim Nelson <jnelson src gnome org>]

commit 7f86ab66d36e9dad6bed8f11652fe69fa1bcaf58
Author: Jim Nelson <jim yorba org>
Date:   Mon Mar 2 17:27:32 2015 -0800

    Better filling of window, prevent soft assertions when chg folders/exiting

 src/client/application/geary-controller.vala |    3 +-
 src/engine/app/app-conversation-monitor.vala |   34 +++++++++++++++++++++----
 2 files changed, 30 insertions(+), 7 deletions(-)
---
diff --git a/src/client/application/geary-controller.vala b/src/client/application/geary-controller.vala
index 4d354da..21fcde2 100644
--- a/src/client/application/geary-controller.vala
+++ b/src/client/application/geary-controller.vala
@@ -56,6 +56,7 @@ public class GearyController : Geary.BaseObject {
     public const string PROP_CURRENT_CONVERSATION ="current-conversations";
     
     public const int MIN_CONVERSATION_COUNT = 50;
+    public const int LOAD_MORE_CONVERSATION_COUNT = 20;
     
     private const string DELETE_MESSAGE_TOOLTIP_SINGLE = _("Delete conversation (Shift+Delete)");
     private const string DELETE_MESSAGE_TOOLTIP_MULTIPLE = _("Delete conversations (Shift+Delete)");
@@ -1455,7 +1456,7 @@ public class GearyController : Geary.BaseObject {
     
     private void on_load_more() {
         debug("on_load_more");
-        current_conversations.min_window_count += MIN_CONVERSATION_COUNT;
+        current_conversations.min_window_count += LOAD_MORE_CONVERSATION_COUNT;
     }
     
     private void on_select_folder_completed(Object? source, AsyncResult result) {
diff --git a/src/engine/app/app-conversation-monitor.vala b/src/engine/app/app-conversation-monitor.vala
index 919a69e..2ce5789 100644
--- a/src/engine/app/app-conversation-monitor.vala
+++ b/src/engine/app/app-conversation-monitor.vala
@@ -13,7 +13,7 @@ public class Geary.App.ConversationMonitor : BaseObject {
         Geary.Email.Field.FLAGS | Geary.Email.Field.DATE;
     
     // # of messages to load at a time as we attempt to fill the min window.
-    private const int WINDOW_FILL_MESSAGE_COUNT = 10;
+    private const int MIN_FILL_MESSAGE_COUNT = 5;
     
     private const Geary.SpecialFolderType[] BLACKLISTED_FOLDER_TYPES = {
         Geary.SpecialFolderType.SPAM,
@@ -247,8 +247,7 @@ public class Geary.App.ConversationMonitor : BaseObject {
         if (is_monitoring)
             debug("Warning: Conversations object destroyed without stopping monitoring");
         
-        foreach (Conversation conversation in conversations)
-            conversation.clear_owner();
+        clear();
     }
     
     protected virtual void notify_monitoring_started() {
@@ -417,10 +416,21 @@ public class Geary.App.ConversationMonitor : BaseObject {
         
         notify_monitoring_stopped();
         
+        clear();
+        
         if (close_err != null)
             throw close_err;
     }
     
+    private void clear() {
+        foreach (Conversation conversation in conversations)
+            conversation.clear_owner();
+        
+        conversations.clear();
+        all_email_id_to_conversation.clear();
+        primary_email_id_to_conversation.clear();
+    }
+    
     // By passing required_fields, this forces the email to be downloaded (if not already) at the
     // potential expense of loading it twice; use Email.Field.NONE to only load the email identifiers
     // and potentially not be able to load the email due to unavailability (but will be loaded
@@ -784,6 +794,10 @@ public class Geary.App.ConversationMonitor : BaseObject {
         
         int initial_message_count = get_email_count();
         
+        debug("fill_window_async: is_insert=%s min_window_count=%d conversations.size=%d primary_ids.size=%d 
initial_message_count=%d",
+            is_insert.to_string(), min_window_count, conversations.size, 
primary_email_id_to_conversation.size,
+            initial_message_count);
+        
         // only do local-load if the Folder isn't completely opened, otherwise this operation
         // will block other (more important) operations while it waits for the folder to
         // remote-open
@@ -808,7 +822,7 @@ public class Geary.App.ConversationMonitor : BaseObject {
         if (low_id != null && !is_insert) {
             // Load at least as many messages as remaining conversations.
             int num_to_load = Numeric.int_floor(min_window_count - conversations.size,
-                WINDOW_FILL_MESSAGE_COUNT);
+                MIN_FILL_MESSAGE_COUNT);
             
             yield load_by_id_async(low_id, num_to_load, Email.Field.NONE, flags, cancellable_monitor);
         } else {
@@ -817,8 +831,16 @@ public class Geary.App.ConversationMonitor : BaseObject {
             yield load_by_id_async(null, min_window_count, Email.Field.NONE, flags, cancellable_monitor);
         }
         
-        // Run again to make sure we're full unless we ran out of messages.
-        if (get_email_count() != initial_message_count)
+        // Run again to make sure we're full ... precondition checking is relied on to prevent
+        // continuous looping of FillWindowOperations
+        bool rescheduled = false;
+        if (conversations.size < min_window_count) {
             operation_queue.add(new FillWindowOperation(this, false));
+            rescheduled = true;
+        }
+        
+        debug("fill_window_async: loaded from %s, email_count=%d primary_ids.size=%d conversations.size=%d 
rescheduled=%s",
+            low_id != null ? low_id.to_string() : "(null)", get_email_count(), 
primary_email_id_to_conversation.size,
+            conversations.size, rescheduled.to_string());
     }
 }