Make [FIROptions defaultOptions] thread safe

FirebaseCore/CHANGELOG.md

@@ -1,3 +1,6 @@
+# Unreleased
+- [changed] Added thread safety to `[FIROptions defaultOptions]` method. (#5915)
+
 # v6.8.0 -- M73
 - [changed] Functionally neutral refactor to simplify FirebaseCore's header usage and replace
   Interop pods with headers only. This change is the reason most of the Firebase pods have a minor

FirebaseCore/Sources/FIROptions.m

@@ -90,40 +90,40 @@ @implementation FIROptions {
 
 static FIROptions *sDefaultOptions = nil;
 static NSDictionary *sDefaultOptionsDictionary = nil;
+static dispatch_once_t sDefaultOptionsOnceToken;
+static dispatch_once_t sDefaultOptionsDictionaryOnceToken;
 
 #pragma mark - Public only for internal class methods
 
 + (FIROptions *)defaultOptions {
-  if (sDefaultOptions != nil) {
-    return sDefaultOptions;
-  }
-
-  NSDictionary *defaultOptionsDictionary = [self defaultOptionsDictionary];
-  if (defaultOptionsDictionary == nil) {
-    return nil;
-  }
+  dispatch_once(&sDefaultOptionsOnceToken, ^{
+    NSDictionary *defaultOptionsDictionary = [self defaultOptionsDictionary];
+    if (defaultOptionsDictionary != nil) {
+      sDefaultOptions =
+          [[FIROptions alloc] initInternalWithOptionsDictionary:defaultOptionsDictionary];
+    }
+  });
 
-  sDefaultOptions = [[FIROptions alloc] initInternalWithOptionsDictionary:defaultOptionsDictionary];
   return sDefaultOptions;
 }
 
 #pragma mark - Private class methods
 
 + (NSDictionary *)defaultOptionsDictionary {
-  if (sDefaultOptionsDictionary != nil) {
-    return sDefaultOptionsDictionary;
-  }
-  NSString *plistFilePath = [FIROptions plistFilePathWithName:kServiceInfoFileName];
-  if (plistFilePath == nil) {
-    return nil;
-  }
-  sDefaultOptionsDictionary = [NSDictionary dictionaryWithContentsOfFile:plistFilePath];
-  if (sDefaultOptionsDictionary == nil) {
-    FIRLogError(kFIRLoggerCore, @"I-COR000011",
-                @"The configuration file is not a dictionary: "
-                @"'%@.%@'.",
-                kServiceInfoFileName, kServiceInfoFileType);
-  }
+  dispatch_once(&sDefaultOptionsDictionaryOnceToken, ^{
+    NSString *plistFilePath = [FIROptions plistFilePathWithName:kServiceInfoFileName];
+    if (plistFilePath == nil) {
+      return;
+    }
+    sDefaultOptionsDictionary = [NSDictionary dictionaryWithContentsOfFile:plistFilePath];
+    if (sDefaultOptionsDictionary == nil) {
+      FIRLogError(kFIRLoggerCore, @"I-COR000011",
+                  @"The configuration file is not a dictionary: "
+                  @"'%@.%@'.",
+                  kServiceInfoFileName, kServiceInfoFileType);
+    }
+  });
+
   return sDefaultOptionsDictionary;
 }
 
@@ -144,6 +144,8 @@ + (NSString *)plistFilePathWithName:(NSString *)fileName {
 + (void)resetDefaultOptions {
   sDefaultOptions = nil;
   sDefaultOptionsDictionary = nil;
+  sDefaultOptionsOnceToken = 0;
+  sDefaultOptionsDictionaryOnceToken = 0;
 }
 
 #pragma mark - Private instance methods

FirebaseCore/Tests/Unit/FIROptionsTest.m

@@ -81,6 +81,38 @@ - (void)testDefaultOptions {
   XCTAssertEqualObjects(options.deepLinkURLScheme, kDeepLinkURLScheme);
 }
 
+- (void)testDefaultOptionsAreInitializedOnce {
+  id mockBundleUtil = OCMClassMock([FIRBundleUtil class]);
+  OCMExpect([mockBundleUtil optionsDictionaryPathWithResourceName:kServiceInfoFileName
+                                                      andFileType:kServiceInfoFileType
+                                                        inBundles:[FIRBundleUtil relevantBundles]])
+      .andReturn([self validGoogleServicesInfoPlistPath]);
+  XCTAssertNotNil([FIROptions defaultOptions]);
+  OCMVerifyAll(mockBundleUtil);
+
+  OCMReject([mockBundleUtil optionsDictionaryPathWithResourceName:OCMOCK_ANY
+                                                      andFileType:OCMOCK_ANY
+                                                        inBundles:OCMOCK_ANY]);
+  XCTAssertNotNil([FIROptions defaultOptions]);
+  OCMVerifyAll(mockBundleUtil);
+}
+
+- (void)testDefaultOptionsDictionaryIsInitializedOnce {
+  id mockBundleUtil = OCMClassMock([FIRBundleUtil class]);
+  OCMExpect([mockBundleUtil optionsDictionaryPathWithResourceName:kServiceInfoFileName
+                                                      andFileType:kServiceInfoFileType
+                                                        inBundles:[FIRBundleUtil relevantBundles]])
+      .andReturn([self validGoogleServicesInfoPlistPath]);
+  XCTAssertNotNil([FIROptions defaultOptionsDictionary]);
+  OCMVerifyAll(mockBundleUtil);
+
+  OCMReject([mockBundleUtil optionsDictionaryPathWithResourceName:OCMOCK_ANY
+                                                      andFileType:OCMOCK_ANY
+                                                        inBundles:OCMOCK_ANY]);
+  XCTAssertNotNil([FIROptions defaultOptionsDictionary]);
+  OCMVerifyAll(mockBundleUtil);
+}
+
 - (void)testInitCustomizedOptions {
   FIROptions *options = [[FIROptions alloc] initWithGoogleAppID:kGoogleAppID
                                                     GCMSenderID:kGCMSenderID];
@@ -98,13 +130,7 @@ - (void)testInitCustomizedOptions {
 }
 
 - (void)testInitWithContentsOfFile {
-  NSString *filePath = [[NSBundle mainBundle] pathForResource:@"GoogleService-Info"
-                                                       ofType:@"plist"];
-  if (filePath == nil) {
-    // Use bundleForClass to allow GoogleService-Info.plist to be in the test target's bundle.
-    NSBundle *bundle = [NSBundle bundleForClass:[self class]];
-    filePath = [bundle pathForResource:@"GoogleService-Info" ofType:@"plist"];
-  }
+  NSString *filePath = [self validGoogleServicesInfoPlistPath];
   FIROptions *options = [[FIROptions alloc] initWithContentsOfFile:filePath];
   [self assertOptionsMatchDefaults:options andProjectID:YES];
   XCTAssertNil(options.deepLinkURLScheme);
@@ -627,4 +653,19 @@ - (void)testVersionConsistency2 {
   XCTAssertEqualObjects(str, [NSString stringWithUTF8String:(const char *)FIRCoreVersionString]);
 }
 
+#pragma mark - Helpers
+
+- (NSString *)validGoogleServicesInfoPlistPath {
+  NSString *filePath = [[NSBundle mainBundle] pathForResource:@"GoogleService-Info"
+                                                       ofType:@"plist"];
+  if (filePath == nil) {
+    // Use bundleForClass to allow GoogleService-Info.plist to be in the test target's bundle.
+    NSBundle *bundle = [NSBundle bundleForClass:[self class]];
+    filePath = [bundle pathForResource:@"GoogleService-Info" ofType:@"plist"];
+  }
+
+  XCTAssertNotNil(filePath);
+  return filePath;
+}
+
 @end