Change CredentialsProvider::TokenListener to use StatusOr<Token> (#945)

* Change CredentialsProvider::TokenListener to use StatusOr

Rather than a token plus error code/msg.

* Eliminate the concept of an invalid Token

Instead, we'll just use StatusOr<Token>. Note that unauthenticated
tokens are handled as a special case; they're created via:
  Token::Unauthenticated()
and are otherwise "valid", though attempting to retrieve the raw token
on one of these tokens will cause an assertion failure.

1 files changed, 35 insertions, 21 deletions

diff --git a/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm b/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm
index 1babe82..2bd3acc 100644
--- a/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm
+++ b/Firestore/core/src/firebase/firestore/auth/firebase_credentials_provider_apple.mm
@@ -23,6 +23,9 @@
 #include "Firestore/core/src/firebase/firestore/util/firebase_assert.h"
 #include "Firestore/core/src/firebase/firestore/util/string_apple.h"
 
+// NB: This is also defined in Firestore/Source/Public/FIRFirestoreErrors.h
+NSString* const FIRFirestoreErrorDomain = @"FIRFirestoreErrorDomain";
+
 namespace firebase {
 namespace firestore {
 namespace auth {
@@ -84,27 +87,38 @@ void FirebaseCredentialsProvider::GetToken(bool force_refresh,
   int initial_user_counter = contents_->user_counter;
 
   std::weak_ptr<Contents> weak_contents = contents_;
-  void (^get_token_callback)(NSString*, NSError*) = ^(
-      NSString* _Nullable token, NSError* _Nullable error) {
-    std::shared_ptr<Contents> contents = weak_contents.lock();
-    if (!contents) {
-      return;
-    }
-
-    std::unique_lock<std::mutex> lock(contents->mutex);
-    if (initial_user_counter != contents->user_counter) {
-      // Cancel the request since the user changed while the request was
-      // outstanding so the response is likely for a previous user (which
-      // user, we can't be sure).
-      completion(Token::Invalid(), FirestoreErrorCode::Aborted,
-                 "getToken aborted due to user change.");
-    } else {
-      completion(
-          Token{util::MakeStringView(token), contents->current_user},
-          error == nil ? FirestoreErrorCode::Ok : error.code,
-          error == nil ? "" : util::MakeStringView(error.localizedDescription));
-    }
-  };
+  void (^get_token_callback)(NSString*, NSError*) =
+      ^(NSString* _Nullable token, NSError* _Nullable error) {
+        std::shared_ptr<Contents> contents = weak_contents.lock();
+        if (!contents) {
+          return;
+        }
+
+        std::unique_lock<std::mutex> lock(contents->mutex);
+        if (initial_user_counter != contents->user_counter) {
+          // Cancel the request since the user changed while the request was
+          // outstanding so the response is likely for a previous user (which
+          // user, we can't be sure).
+          completion(util::Status(FirestoreErrorCode::Aborted,
+                                  "getToken aborted due to user change."));
+        } else {
+          if (error == nil) {
+            if (token != nil) {
+              completion(
+                  Token{util::MakeStringView(token), contents->current_user});
+            } else {
+              completion(Token::Unauthenticated());
+            }
+          } else {
+            FirestoreErrorCode error_code = FirestoreErrorCode::Unknown;
+            if (error.domain == FIRFirestoreErrorDomain) {
+              error_code = static_cast<FirestoreErrorCode>(error.code);
+            }
+            completion(util::Status(
+                error_code, util::MakeStringView(error.localizedDescription)));
+          }
+        }
+      };
 
   [contents_->app getTokenForcingRefresh:force_refresh
                             withCallback:get_token_callback];