Installations: access FIRHeartbeatInfo from a background thread (#5114)

* FIS: assert heartbeat storage is not accessed in main thread.

* FIS: Access hearbeat storage from a background queue.

Author: maksymmalyhin

FirebaseInstallations/Source/Library/InstallationsAPI/FIRInstallationsAPIService.m

@@ -92,17 +92,21 @@ - (instancetype)initWithURLSession:(NSURLSession *)URLSession
 #pragma mark - Public
 
 - (FBLPromise<FIRInstallationsItem *> *)registerInstallation:(FIRInstallationsItem *)installation {
-  NSURLRequest *request = [self registerRequestWithInstallation:installation];
-  return [self sendURLRequest:request].then(
-      ^id _Nullable(FIRInstallationsURLSessionResponse *response) {
+  return [self registerRequestWithInstallation:installation]
+      .then(^id _Nullable(NSURLRequest *_Nullable request) {
+        return [self sendURLRequest:request];
+      })
+      .then(^id _Nullable(FIRInstallationsURLSessionResponse *response) {
         return [self registeredInstallationWithInstallation:installation serverResponse:response];
       });
 }
 
 - (FBLPromise<FIRInstallationsItem *> *)refreshAuthTokenForInstallation:
     (FIRInstallationsItem *)installation {
-  NSURLRequest *request = [self authTokenRequestWithInstallation:installation];
-  return [self sendURLRequest:request]
+  return [self authTokenRequestWithInstallation:installation]
+      .then(^id _Nullable(NSURLRequest *_Nullable request) {
+        return [self sendURLRequest:request];
+      })
       .then(^FBLPromise<FIRInstallationsStoredAuthToken *> *(
           FIRInstallationsURLSessionResponse *response) {
         return [self authTokenWithServerResponse:response];
@@ -115,17 +119,20 @@ - (instancetype)initWithURLSession:(NSURLSession *)URLSession
 }
 
 - (FBLPromise<FIRInstallationsItem *> *)deleteInstallation:(FIRInstallationsItem *)installation {
-  NSURLRequest *request = [self deleteInstallationRequestWithInstallation:installation];
-  return [[self sendURLRequest:request]
-      then:^id _Nullable(FIRInstallationsURLSessionResponse *_Nullable value) {
+  return [self deleteInstallationRequestWithInstallation:installation]
+      .then(^id _Nullable(NSURLRequest *_Nullable request) {
+        return [self sendURLRequest:request];
+      })
+      .then(^id _Nullable(FIRInstallationsURLSessionResponse *_Nullable value) {
         // Return the original installation on success.
         return installation;
-      }];
+      });
 }
 
 #pragma mark - Register Installation
 
-- (NSURLRequest *)registerRequestWithInstallation:(FIRInstallationsItem *)installation {
+- (FBLPromise<NSURLRequest *> *)registerRequestWithInstallation:
+    (FIRInstallationsItem *)installation {
   NSString *URLString = [NSString stringWithFormat:@"%@/v1/projects/%@/installations/",
                                                    kFIRInstallationsAPIBaseURL, self.projectID];
   NSURL *URL = [NSURL URLWithString:URLString];
@@ -176,7 +183,8 @@ - (NSURLRequest *)registerRequestWithInstallation:(FIRInstallationsItem *)instal
 
 #pragma mark - Auth token
 
-- (NSURLRequest *)authTokenRequestWithInstallation:(FIRInstallationsItem *)installation {
+- (FBLPromise<NSURLRequest *> *)authTokenRequestWithInstallation:
+    (FIRInstallationsItem *)installation {
   NSString *URLString =
       [NSString stringWithFormat:@"%@/v1/projects/%@/installations/%@/authTokens:generate",
                                  kFIRInstallationsAPIBaseURL, self.projectID,
@@ -216,7 +224,8 @@ - (NSURLRequest *)authTokenRequestWithInstallation:(FIRInstallationsItem *)insta
 
 #pragma mark - Delete Installation
 
-- (NSURLRequest *)deleteInstallationRequestWithInstallation:(FIRInstallationsItem *)installation {
+- (FBLPromise<NSURLRequest *> *)deleteInstallationRequestWithInstallation:
+    (FIRInstallationsItem *)installation {
   NSString *URLString = [NSString stringWithFormat:@"%@/v1/projects/%@/installations/%@/",
                                                    kFIRInstallationsAPIBaseURL, self.projectID,
                                                    installation.firebaseInstallationID];
@@ -229,45 +238,52 @@ - (NSURLRequest *)deleteInstallationRequestWithInstallation:(FIRInstallationsIte
 }
 
 #pragma mark - URL Request
-- (NSURLRequest *)requestWithURL:(NSURL *)requestURL
-                      HTTPMethod:(NSString *)HTTPMethod
-                        bodyDict:(NSDictionary *)bodyDict
-                    refreshToken:(nullable NSString *)refreshToken {
+- (FBLPromise<NSURLRequest *> *)requestWithURL:(NSURL *)requestURL
+                                    HTTPMethod:(NSString *)HTTPMethod
+                                      bodyDict:(NSDictionary *)bodyDict
+                                  refreshToken:(nullable NSString *)refreshToken {
   return [self requestWithURL:requestURL
                    HTTPMethod:HTTPMethod
                      bodyDict:bodyDict
                  refreshToken:refreshToken
             additionalHeaders:nil];
 }
 
-- (NSURLRequest *)requestWithURL:(NSURL *)requestURL
-                      HTTPMethod:(NSString *)HTTPMethod
-                        bodyDict:(NSDictionary *)bodyDict
-                    refreshToken:(nullable NSString *)refreshToken
-               additionalHeaders:
-                   (nullable NSDictionary<NSString *, NSString *> *)additionalHeaders {
-  __block NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:requestURL];
-  request.HTTPMethod = HTTPMethod;
-  NSString *bundleIdentifier = [[NSBundle mainBundle] bundleIdentifier];
-  [request addValue:self.APIKey forHTTPHeaderField:kFIRInstallationsAPIKey];
-  [request addValue:bundleIdentifier forHTTPHeaderField:kFIRInstallationsBundleId];
-  [self setJSONHTTPBody:bodyDict forRequest:request];
-  if (refreshToken) {
-    NSString *authHeader = [NSString stringWithFormat:@"FIS_v2 %@", refreshToken];
-    [request setValue:authHeader forHTTPHeaderField:@"Authorization"];
-  }
-  // User agent Header.
-  [request setValue:[FIRApp firebaseUserAgent] forHTTPHeaderField:kFIRInstallationsUserAgentKey];
-  // Heartbeat Header.
-  [request setValue:@([FIRHeartbeatInfo heartbeatCodeForTag:kFIRInstallationsHeartbeatTag])
-                        .stringValue
-      forHTTPHeaderField:kFIRInstallationsHeartbeatKey];
-  [additionalHeaders enumerateKeysAndObjectsUsingBlock:^(
-                         NSString *_Nonnull key, NSString *_Nonnull obj, BOOL *_Nonnull stop) {
-    [request setValue:obj forHTTPHeaderField:key];
-  }];
-
-  return [request copy];
+- (FBLPromise<NSURLRequest *> *)requestWithURL:(NSURL *)requestURL
+                                    HTTPMethod:(NSString *)HTTPMethod
+                                      bodyDict:(NSDictionary *)bodyDict
+                                  refreshToken:(nullable NSString *)refreshToken
+                             additionalHeaders:(nullable NSDictionary<NSString *, NSString *> *)
+                                                   additionalHeaders {
+  return [FBLPromise
+      onQueue:dispatch_get_global_queue(QOS_CLASS_UTILITY, 0)
+           do:^id _Nullable {
+             __block NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:requestURL];
+             request.HTTPMethod = HTTPMethod;
+             NSString *bundleIdentifier = [[NSBundle mainBundle] bundleIdentifier];
+             [request addValue:self.APIKey forHTTPHeaderField:kFIRInstallationsAPIKey];
+             [request addValue:bundleIdentifier forHTTPHeaderField:kFIRInstallationsBundleId];
+             [self setJSONHTTPBody:bodyDict forRequest:request];
+             if (refreshToken) {
+               NSString *authHeader = [NSString stringWithFormat:@"FIS_v2 %@", refreshToken];
+               [request setValue:authHeader forHTTPHeaderField:@"Authorization"];
+             }
+             // User agent Header.
+             [request setValue:[FIRApp firebaseUserAgent]
+                 forHTTPHeaderField:kFIRInstallationsUserAgentKey];
+             // Heartbeat Header.
+             [request setValue:@([FIRHeartbeatInfo
+                                     heartbeatCodeForTag:kFIRInstallationsHeartbeatTag])
+                                   .stringValue
+                 forHTTPHeaderField:kFIRInstallationsHeartbeatKey];
+             [additionalHeaders
+                 enumerateKeysAndObjectsUsingBlock:^(NSString *_Nonnull key, NSString *_Nonnull obj,
+                                                     BOOL *_Nonnull stop) {
+                   [request setValue:obj forHTTPHeaderField:key];
+                 }];
+
+             return [request copy];
+           }];
 }
 
 - (FBLPromise<FIRInstallationsURLSessionResponse *> *)URLRequestPromise:(NSURLRequest *)request {

FirebaseInstallations/Source/Tests/Unit/FIRInstallationsAPIServiceTests.m

@@ -56,6 +56,9 @@ - (void)setUp {
                                                               projectID:self.projectID];
   self.heartbeatMock = OCMClassMock([FIRHeartbeatInfo class]);
   OCMStub([self.heartbeatMock heartbeatCodeForTag:@"fire-installations"])
+      .andDo(^(NSInvocation *invocation) {
+        XCTAssertFalse([NSThread isMainThread]);
+      })
       .andReturn(FIRHeartbeatInfoCodeCombined);
 }