1 files changed, 43 insertions, 0 deletions
diff --git a/Firebase/Core/FIRURLSchemeUtil.m b/Firebase/Core/FIRURLSchemeUtil.m
new file mode 100644
index 0000000..8dbecae
--- /dev/null
+++ b/Firebase/Core/FIRURLSchemeUtil.m
@@ -0,0 +1,43 @@
+// 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 "Private/FIRURLSchemeUtil.h"
+#import "Private/FIRLogger.h"
+
+/**
+ * Regular expression to match the URL scheme for Google sign-in.
+ */
+static NSString *const kFIRGoogleSignInURLSchemePattern =
+@"^com\\.googleusercontent\\.apps\\.\\d+-\\w+$";
+
+BOOL fir_areURLSchemesValidForGoogleSignIn(NSArray *urlSchemes) {
+  BOOL hasReversedClientID = NO;
+  for (NSString *urlScheme in urlSchemes) {
+    if (!hasReversedClientID) {
+      NSRange range = [urlScheme rangeOfString:kFIRGoogleSignInURLSchemePattern
+                                       options:NSRegularExpressionSearch];
+      if (range.location != NSNotFound) {
+        hasReversedClientID = YES;
+      }
+    }
+  }
+  if (hasReversedClientID) {
+    return YES;
+  }
+  if (!hasReversedClientID) {
+    FIRLogInfo(kFIRLoggerCore, @"I-COR000021", @"A reversed client ID should be added as a URL "
+              @"scheme to enable Google sign-in.");
+  }
+  return NO;
+}