[MOD/WIP] Parallel awaiting of notifications

Passed the very basic test with the tanuki account, over two sessions.

src/User.c

@@ -1665,28 +1665,44 @@ void
 UserNotifyUser(User *user)
 {
     NotificationEntry *entry;
+    Array *entries;
+    size_t size, i;
     if (!user || !pushTable)
     {
         return;
     }
     pthread_mutex_lock(&pushLock);
-    entry = HashMapGet(pushTable, user->name);
+    entries = HashMapGet(pushTable, user->name);
+    size = ArraySize(entries);
+    entry = ArrayGet(entries, 0);
     if (entry && entry->type == NOTIF_AWAIT)
     {
-        pthread_mutex_lock(&entry->lock);
-        entry->notified = true;
-        pthread_cond_signal(&entry->cond);
-        pthread_mutex_unlock(&entry->lock);
+        /* First element being an await -> wake up everyone */
+        for (i = 0; i < size; i++)
+        {
+            entry = ArrayGet(entries, i);
+            pthread_mutex_lock(&entry->lock);
+            entry->notified = true;
+            pthread_cond_signal(&entry->cond);
+            pthread_mutex_unlock(&entry->lock);
+        }
 
         pthread_mutex_unlock(&pushLock);
         return;
     }
     else if (!entry)
     {
+        /* No elements in the awaits, create a notification note */
+        if (!entries)
+        {
+            entries = ArrayCreate();
+        }
+
         entry = Malloc(sizeof(*entry));
         entry->type = NOTIF_GOTTEN;
+        ArrayAdd(entries, entry);
 
-        HashMapSet(pushTable, user->name, entry);
+        HashMapSet(pushTable, user->name, entries);
         pthread_mutex_unlock(&pushLock);
         return;
     }
@@ -1698,12 +1714,29 @@ UserNotifyUser(User *user)
 void
 UserDestroyPushTable(void)
 {
+    char *key;
+    Array *value;
     if (!pushTable)
     {
         return;
     }
 
     pthread_mutex_lock(&pushLock);
+    while (HashMapIterate(pushTable, &key, (void **) &value))
+    {
+        size_t i;
+        for (i = 0; i < ArraySize(value); i++)
+        {
+            NotificationEntry *entry = ArrayGet(value, i);
+
+            /* Should we use the Memory API? */
+            if (entry->type == NOTIF_GOTTEN)
+            {
+                Free(entry);
+            }
+        }
+        ArrayFree(value);
+    }
     HashMapFree(pushTable);
     pushTable = NULL;
     pthread_mutex_unlock(&pushLock);
@@ -1714,9 +1747,11 @@ bool
 UserAwaitNotification(char *user, int await)
 {
     NotificationEntry *entry, ownEntry;
+    Array *entries;
     struct timespec timeout;
     int code;
     bool timedout = false, notified = false;
+    size_t i;
     if (!user)
     {
         return false;
@@ -1731,25 +1766,33 @@ UserAwaitNotification(char *user, int await)
     pthread_mutex_lock(&pushLock);
 
     /* Check if we got any notifications yet. */
-    entry = HashMapGet(pushTable, user);
+    entries = HashMapGet(pushTable, user);
+    entry = ArrayGet(entries, 0);
     if (entry && entry->type == NOTIF_GOTTEN)
     {
         /* Got a notification entry already. */
-        Free(entry);
-        HashMapDelete(pushTable, user);
+        entries = HashMapDelete(pushTable, user);
+        for (i = 0; i < ArraySize(entries); i++)
+        {
+            NotificationEntry *entry = ArrayGet(entries, i);
+
+            /* Should we use the Memory API? */
+            if (entry->type == NOTIF_GOTTEN)
+            {
+                Free(entry);
+            }
+        }
+        ArrayFree(entries);
+
         pthread_mutex_unlock(&pushLock);
 
         return true;
     }
-    else if (entry)
-    {
-        /* Another thread's awaiting... TODO: Manage these conditions. */
-        Log(LOG_ERR, 
-            "Unimplemented feature: awaiting for other threads."
-        );
 
-        pthread_mutex_unlock(&pushLock);
-        return false;
+    if (!entries)
+    {
+        entries = ArrayCreate();
+        HashMapSet(pushTable, user, entries);
     }
 
     /* No one's waiting or notifying; let's create our own entry, 
@@ -1761,7 +1804,7 @@ UserAwaitNotification(char *user, int await)
     entry->notified = false;
     pthread_mutex_init(&entry->lock, NULL);
     pthread_cond_init(&entry->cond, NULL);
-    HashMapSet(pushTable, user, entry);
+    ArrayAdd(entries, entry);
     pthread_mutex_unlock(&pushLock);
 
     /* Now, it's time for us to wait. */
@@ -1794,7 +1837,15 @@ UserAwaitNotification(char *user, int await)
     notified = !timedout && entry->notified;
 
     pthread_mutex_lock(&pushLock);
-    HashMapDelete(pushTable, user);
+    for (i = 0; i < ArraySize(entries); i++)
+    {
+        NotificationEntry *subEntry = ArrayGet(entries, i);
+        if (subEntry == entry)
+        {
+            ArrayDelete(entries, i);
+            break;
+        }
+    }
     pthread_mutex_unlock(&pushLock);
 
     return notified;