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, 42 insertions, 0 deletions

diff --git a/Firestore/Source/Model/FSTDocumentDictionary.mm b/Firestore/Source/Model/FSTDocumentDictionary.mm
new file mode 100644
index 0000000..362af54
--- /dev/null
+++ b/Firestore/Source/Model/FSTDocumentDictionary.mm
@@ -0,0 +1,42 @@
+/*
+ * 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/Model/FSTDocumentDictionary.h"
+
+#import "Firestore/Source/Model/FSTDocumentKey.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@implementation FSTImmutableSortedDictionary (FSTMaybeDocumentDictionary)
+
++ (instancetype)maybeDocumentDictionary {
+  // Immutable dictionaries are contravariant in their value type, so just return a
+  // FSTDocumentDictionary here.
+  return [FSTDocumentDictionary documentDictionary];
+}
+
++ (instancetype)documentDictionary {
+  static FSTDocumentDictionary *singleton;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    singleton = [FSTDocumentDictionary dictionaryWithComparator:FSTDocumentKeyComparator];
+  });
+  return singleton;
+}
+
+@end
+
+NS_ASSUME_NONNULL_END