Move all Firestore Objective-C to Objective-C++ (#734)

* Move all Firestore files to Objective-C++
* Update project file references
* Don't use module imports from Objective-C++
* Use extern "C" for C-accessible globals
* Work around more stringent type checking in Objective-C++
  * NSMutableDictionary ivars aren't implicitly casted to NSDictionary
  * FSTMaybeDocument callback can't be passed a function that accepts
    FSTDocument
  * NSComparisonResult can't be multiplied by -1 without casting
* Add a #include <inttypes.h> where needed
* Avoid using C++ keywords as variables
* Remove #if __cplusplus guards

1 files changed, 50 insertions, 0 deletions

diff --git a/Firestore/Source/Util/FSTAsyncQueryListener.mm b/Firestore/Source/Util/FSTAsyncQueryListener.mm
new file mode 100644
index 0000000..d98e2dd
--- /dev/null
+++ b/Firestore/Source/Util/FSTAsyncQueryListener.mm
@@ -0,0 +1,50 @@
+/*
+ * Copyright 2017 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#import "Firestore/Source/Util/FSTAsyncQueryListener.h"
+
+#import "Firestore/Source/Util/FSTDispatchQueue.h"
+
+@implementation FSTAsyncQueryListener {
+  volatile BOOL _muted;
+  FSTViewSnapshotHandler _snapshotHandler;
+  FSTDispatchQueue *_dispatchQueue;
+}
+
+- (instancetype)initWithDispatchQueue:(FSTDispatchQueue *)dispatchQueue
+                      snapshotHandler:(FSTViewSnapshotHandler)snapshotHandler {
+  if (self = [super init]) {
+    _dispatchQueue = dispatchQueue;
+    _snapshotHandler = snapshotHandler;
+  }
+  return self;
+}
+
+- (FSTViewSnapshotHandler)asyncSnapshotHandler {
+  return ^(FSTViewSnapshot *_Nullable snapshot, NSError *_Nullable error) {
+    [_dispatchQueue dispatchAsync:^{
+      if (!_muted) {
+        _snapshotHandler(snapshot, error);
+      }
+    }];
+  };
+}
+
+- (void)mute {
+  _muted = true;
+}
+
+@end