patcoll · April 15, 2011 20:55 · Apr 15, 2011
diff --git a/AppDelegate.h b/AppDelegate.h
@@ -0,0 +1,10 @@
+#define SYNC_INTERVAL 60
+
+@interface AppDelegate : NSObject <UIApplicationDelegate> {
+    // ...
+    NSMutableDictionary *mocs;
+    NSMutableDictionary *mocThreads;
+    // ...
+}
+@property (nonatomic, retain) NSMutableDictionary *mocs;
+@property (nonatomic, retain) NSMutableDictionary *mocThreads;
diff --git a/AppDelegate.m b/AppDelegate.m
@@ -0,0 +1,132 @@
+// put this somewhere in @implementation:
+// @synthesize mocs, mocThreads;
+
+- (void)awakeFromNib {
+    [NSTimer scheduledTimerWithTimeInterval:SYNC_INTERVAL target:self selector:@selector(sync) userInfo:nil repeats:YES];
+
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(threadWillExit:) 
+                                                 name:NSThreadWillExitNotification
+                                               object:nil];
+}
+
+- (void) sync
+{
+    [self performSelectorInBackground:@selector(doSync) withObject:nil];
+}
+
+- (void) doSync
+{
+    NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];
+
+    NSManagedObjectContext *ctx = [self managedObjectContext];
+    // sync! ctx will be a fresh MOC within a new thread
+
+    [pool release];
+}
+
+
+- (void) threadWillExit:(NSNotification *)notification
+{
+    NSThread *exitingThread = [notification object];
+    [self destroyManagedObjectContextForThreadName:[exitingThread name]];
+}
+
+
+- (void) mergeChanges:(NSNotification *)notification
+{
+    // Merge changes from the MOC that sent the notification to all other MOCs in all other threads.
+    NSManagedObjectContext *mocThatSentNotification = [notification object];
+
+    [mocs enumerateKeysAndObjectsUsingBlock:^(id name, id moc, BOOL *stop) {
+        name = (NSString *)name;
+        moc = (NSManagedObjectContext *)moc;
+        NSThread *thread = [mocThreads objectForKey:name];
+
+        // don't send notifications back to the MOC that sent it.
+        if (![moc isEqual:mocThatSentNotification]) {
+            // waitUntilDone:NO because the thread could exit prematurely -- and we don't really care why.
+            [moc performSelector:@selector(mergeChangesFromContextDidSaveNotification:) onThread:thread withObject:notification waitUntilDone:NO];
+        }
+    }];
+}
+
+
+// ...
+
+/**
+ Returns the managed object context for the current thread.
+ If the context doesn't already exist, it is created and bound to the persistent store coordinator for the application.
+ */
+- (NSManagedObjectContext *)managedObjectContext
+{
+    if (mocs == nil) {
+        self.mocs = [[NSMutableDictionary alloc] init];
+    }
+
+    if (mocThreads == nil) {
+        self.mocThreads = [[NSMutableDictionary alloc] init];
+    }
+
+    static int counter = 0;
+    NSThread *current = [NSThread currentThread];
+
+    if ([current name] != nil && [mocs objectForKey:[current name]] != nil) {
+        return [mocs objectForKey:[current name]];
+    }
+
+    [current setName:[NSString stringWithFormat:@"%d", ++counter]];
+
+    NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator];
+
+    if (coordinator != nil) {
+        NSManagedObjectContext *moc = [[NSManagedObjectContext alloc] init];
+        [moc setPersistentStoreCoordinator:coordinator];
+
+        [[NSNotificationCenter defaultCenter] addObserver:self
+                                                 selector:@selector(mergeChanges:) 
+                                                     name:NSManagedObjectContextDidSaveNotification
+                                                   object:moc];
+        [mocs setObject:moc forKey:[current name]];
+        [mocThreads setObject:current forKey:[current name]];
+    }
+
+    return [mocs objectForKey:[current name]];
+}
+
+- (NSPersistentStoreCoordinator *)persistentStoreCoordinator {
+    // return a valid NSPersistentStoreCoordinator
+}
+
+- (NSString *) mainThreadName
+{
+    NSSet *mainThreadNameSet = [mocThreads keysOfEntriesWithOptions:NSEnumerationConcurrent passingTest:^BOOL(id key, id obj, BOOL *stop) {
+        return [obj isEqual:[NSThread mainThread]];
+    }];
+    return [mainThreadNameSet anyObject];
+}
+
+- (NSManagedObjectContext *)mainManagedObjectContext
+{
+    [self managedObjectContext];
+    return [mocs objectForKey:[self mainThreadName]];
+}
+
+- (void) destroyManagedObjectContextForThreadName:(NSString *)name
+{
+    if (name != nil && [mocs objectForKey:name] != nil) {
+        NSManagedObjectContext *moc = [mocs objectForKey:name];
+        [moc release];
+        moc = nil;
+        [mocs removeObjectForKey:name];
+        [mocThreads removeObjectForKey:name];
+    }
+}
+
+- (void) destroyAllManagedObjectContexts
+{
+    for (NSString *name in [mocs allKeys]) {
+        [self destroyManagedObjectContextForThreadName:name];
+    }
+}
+