[california] Properly handle modified master and generated instances: Bug #735946

[Jim Nelson <jnelson src gnome org>]

commit c873fbc138e143bcbdbc2bbb4120f25920d17b61
Author: Jim Nelson <jim yorba org>
Date:   Thu Sep 4 14:33:21 2014 -0700

    Properly handle modified master and generated instances: Bug #735946
    
    Modified master instances must look for situation where their RRULE
    was dropped (and hence all their generated instances must be dropped).
    Modified generated instances must only update their instance in
    memory and none other.

 .../backing-calendar-source-subscription.vala      |   30 ++++++++++--
 .../backing-eds-calendar-source-subscription.vala  |   53 +++++++++++++-------
 2 files changed, 60 insertions(+), 23 deletions(-)
---
diff --git a/src/backing/backing-calendar-source-subscription.vala 
b/src/backing/backing-calendar-source-subscription.vala
index 0ffd6f7..9286dca 100644
--- a/src/backing/backing-calendar-source-subscription.vala
+++ b/src/backing/backing-calendar-source-subscription.vala
@@ -216,12 +216,13 @@ public abstract class CalendarSourceSubscription : BaseObject {
     }
     
     /**
-     * Remove an { link Component.Instance} from the subscription and notify subscribers.
+     * Remove a master { link Component.Instance} from the subscription as well as its generated
+     * instances and notify subscribers.
      *
-     * @see notify_instance_discovered
+     * @see notify_generated_instance_removed
      * @see instance_removed
      */
-    protected virtual void notify_instance_removed(Component.UID uid) {
+    protected virtual void notify_master_removed(Component.UID uid) {
         Gee.Collection<Component.Instance> removed_instances;
         if (remove_instance(uid, out removed_instances)) {
             foreach (Component.Instance instance in removed_instances)
@@ -232,6 +233,25 @@ public abstract class CalendarSourceSubscription : BaseObject {
     }
     
     /**
+     * Removes a generated { link Component.Instance} from the subscription and notify subscribers.
+     *
+     * @see notify_master_removed
+     * @see instance_removed
+     */
+    protected virtual void notify_generated_instance_removed(Component.UID uid, Component.DateTime rid) {
+        Component.Instance? found = traverse<Component.Instance>(instances.get(uid))
+            .first_matching(inst => inst.rid != null && inst.rid.equal_to(rid));
+        
+        if (found != null) {
+            instances.remove(uid, found);
+            instance_removed(found);
+        } else {
+            debug("Cannot remove UID %s RID %s from %s: not known", uid.to_string(), rid.to_string(),
+                to_string());
+        }
+    }
+    
+    /**
      * Update an altered { link Component.Instance} and notify subscribers.
      *
      * @see notify_instance_discovered
@@ -334,7 +354,9 @@ public abstract class CalendarSourceSubscription : BaseObject {
      * @returns null if the UID has not been seen.
      */
     public Gee.Collection<Component.Instance>? for_uid(Component.UID uid) {
-        return instances.contains(uid) ? instances.get(uid) : null;
+        return instances.contains(uid)
+            ? traverse<Component.Instance>(instances.get(uid)).to_array_list()
+            : null;
     }
     
     public override string to_string() {
diff --git a/src/backing/eds/backing-eds-calendar-source-subscription.vala 
b/src/backing/eds/backing-eds-calendar-source-subscription.vala
index ab1d582..963f9c8 100644
--- a/src/backing/eds/backing-eds-calendar-source-subscription.vala
+++ b/src/backing/eds/backing-eds-calendar-source-subscription.vala
@@ -123,7 +123,7 @@ internal class EdsCalendarSourceSubscription : CalendarSourceSubscription {
             
             // remove all existing components with this UID
             if (has_uid(uid))
-                notify_instance_removed(uid);
+                notify_master_removed(uid);
             
             // add all instances, master and generated
             Component.Instance? master = add_instance(null, ical_component, notifier);
@@ -172,8 +172,8 @@ internal class EdsCalendarSourceSubscription : CalendarSourceSubscription {
     private void on_objects_modified(SList<unowned iCal.icalcomponent> ical_components) {
         SList<unowned iCal.icalcomponent> add_list = new SList<unowned iCal.icalcomponent>();
         foreach (unowned iCal.icalcomponent ical_component in ical_components) {
-            // if not an instance and has recurring, treat as an add (which removes and adds generated
-            // instances)
+            // if not a generated instance and has recurring, treat as an add (which removes and
+            // adds generated instances)
             if (!E.Util.component_is_instance(ical_component) && 
E.Util.component_has_recurrences(ical_component)) {
                 add_list.append(ical_component);
                 
@@ -183,11 +183,15 @@ internal class EdsCalendarSourceSubscription : CalendarSourceSubscription {
             if (String.is_empty(ical_component.get_uid()))
                 continue;
             
-            // if none present, skip
             Component.UID uid = new Component.UID(ical_component.get_uid());
-            if (!has_uid(uid))
+            
+            // if no known instances (master or generated) of this UID, then signalled for something
+            // never seen before
+            Gee.Collection<Component.Instance>? instances = for_uid(uid);
+            if (Collection.size(instances) == 0)
                 continue;
             
+            // if a generated instance has been updated, get its RID (fall through if unavailable)
             Component.DateTime? rid = null;
             try {
                 rid = new Component.DateTime(ical_component, iCal.icalproperty_kind.RECURRENCEID_PROPERTY);
@@ -199,33 +203,44 @@ internal class EdsCalendarSourceSubscription : CalendarSourceSubscription {
                 }
             }
             
-            // get all instances known for this UID to find original to alter
-            Gee.Collection<Component.Instance>? instances = for_uid(uid);
-            
-            // if no RID, then only one should be returned
             Component.Instance? instance = null;
             if (rid == null) {
-                instance = traverse<Component.Instance>(instances).one();
+                // no RID, then this is the master instance; test above looks for an RRULE, so that's
+                // not present any more (if it ever was); drop all generated instances, as this
+                // master no longer has any
+                traverse<Component.Instance>(instances)
+                    .filter(inst => inst.is_generated_instance)
+                    .iterate(inst => notify_generated_instance_removed(inst.uid, inst.rid));
+            
+                // the master instance of the bunch is what's been modified
+                instance = traverse<Component.Instance>(instances)
+                    .filter(inst => inst.is_master_instance)
+                    .one();
                 if (instance == null) {
-                    debug("%d instances found for modified instance, expected 1", 
Collection.size(instances));
-                    
-                    continue;
+                    debug("Cannot find master instance for UID %s (%d generated), skipping",
+                        uid.to_string(), Collection.size(instances));
                 }
+                
             } else {
-                // if RID != null, then find the matching instance
+                // RID found, so a generated instance has been modified; only update that one
                 instance = traverse<Component.Instance>(instances)
-                    .first_matching(inst => inst.rid != null && inst.rid.equal_to(rid));
+                    .filter(inst => inst.rid != null && inst.rid.equal_to(rid))
+                    .one();
                 if (instance == null) {
-                    debug("Cannot find instance with UID %s RID %s, skipping", uid.to_string(), 
rid.to_string());
-                    
-                    continue;
+                    debug("Cannot find generated instance for UID %s RID %s (%d generated), skipping",
+                        uid.to_string(), rid.to_string(), Collection.size(instances));
                 }
             }
             
+            if (instance == null)
+                continue;
+            
+            // only deal with Events at this moment
             Component.Event? modified_event = instance as Component.Event;
             if (modified_event == null)
                 continue;
             
+            // update event details
             try {
                 modified_event.full_update(ical_component, null);
             } catch (Error err) {
@@ -243,7 +258,7 @@ internal class EdsCalendarSourceSubscription : CalendarSourceSubscription {
     
     private void on_objects_removed(SList<unowned E.CalComponentId?> ids) {
         foreach (unowned E.CalComponentId id in ids)
-            notify_instance_removed(new Component.UID(id.uid));
+            notify_master_removed(new Component.UID(id.uid));
     }
 }