1 files changed, 45 insertions, 0 deletions
diff --git a/Firestore/Source/Util/FSTUsageValidation.h b/Firestore/Source/Util/FSTUsageValidation.h
new file mode 100644
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+++ b/Firestore/Source/Util/FSTUsageValidation.h
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+/*
+ * 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.
+ */
+
+#include <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/** Helper for creating a general exception for invalid usage of an API. */
+NSException *FSTInvalidUsage(NSString *exceptionName, NSString *format, ...);
+
+/**
+ * Macro to throw exceptions in response to API usage errors. Avoids the lint warning you usually
+ * get when using @throw and (unlike a function) doesn't trigger warnings about not all codepaths
+ * returning a value.
+ *
+ * Exceptions should only be used for programmer errors made by consumers of the SDK, e.g.
+ * invalid method arguments.
+ *
+ * For recoverable runtime errors, use NSError**.
+ * For internal programming errors, use FSTFail().
+ */
+#define FSTThrowInvalidUsage(exceptionName, format, ...)          \
+  do {                                                            \
+    @throw FSTInvalidUsage(exceptionName, format, ##__VA_ARGS__); \
+  } while (0)
+
+#define FSTThrowInvalidArgument(format, ...)                                       \
+  do {                                                                             \
+    @throw FSTInvalidUsage(@"FIRInvalidArgumentException", format, ##__VA_ARGS__); \
+  } while (0)
+
+NS_ASSUME_NONNULL_END