1 files changed, 186 insertions, 0 deletions
diff --git a/Functions/FirebaseFunctions/FUNError.m b/Functions/FirebaseFunctions/FUNError.m
new file mode 100644
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+++ b/Functions/FirebaseFunctions/FUNError.m
@@ -0,0 +1,186 @@
+// 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 "FUNError.h"
+#import "FIRError.h"
+
+#import "FUNSerializer.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+NSString *const FIRFunctionsErrorDomain = @"com.firebase.functions";
+NSString *const FIRFunctionsErrorDetailsKey = @"details";
+
+/**
+ * Takes an HTTP status code and returns the corresponding FIRFunctionsErrorCode error code.
+ * This is the standard HTTP status code -> error mapping defined in:
+ * https://github.com/googleapis/googleapis/blob/master/google/rpc/code.proto
+ * @param status An HTTP status code.
+ * @return The corresponding error code, or FIRFunctionsErrorCodeUnknown if none.
+ */
+FIRFunctionsErrorCode FIRFunctionsErrorCodeForHTTPStatus(NSInteger status) {
+  switch (status) {
+    case 200:
+      return FIRFunctionsErrorCodeOK;
+    case 400:
+      return FIRFunctionsErrorCodeInvalidArgument;
+    case 401:
+      return FIRFunctionsErrorCodeUnauthenticated;
+    case 403:
+      return FIRFunctionsErrorCodePermissionDenied;
+    case 404:
+      return FIRFunctionsErrorCodeNotFound;
+    case 409:
+      return FIRFunctionsErrorCodeAborted;
+    case 429:
+      return FIRFunctionsErrorCodeResourceExhausted;
+    case 499:
+      return FIRFunctionsErrorCodeCancelled;
+    case 500:
+      return FIRFunctionsErrorCodeInternal;
+    case 501:
+      return FIRFunctionsErrorCodeUnimplemented;
+    case 503:
+      return FIRFunctionsErrorCodeUnavailable;
+    case 504:
+      return FIRFunctionsErrorCodeDeadlineExceeded;
+  }
+  return FIRFunctionsErrorCodeInternal;
+}
+
+/**
+ * Takes the name of an error code and returns the enum value for it.
+ * @param name An error name.
+ * @return The error code with this name, or FIRFunctionsErrorCodeUnknown if none.
+ */
+FIRFunctionsErrorCode FIRFunctionsErrorCodeForName(NSString *name) {
+  static NSDictionary<NSString *, NSNumber *> *errors;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    errors = @{
+      @"OK" : @(FIRFunctionsErrorCodeOK),
+      @"CANCELLED" : @(FIRFunctionsErrorCodeCancelled),
+      @"UNKNOWN" : @(FIRFunctionsErrorCodeUnknown),
+      @"INVALID_ARGUMENT" : @(FIRFunctionsErrorCodeInvalidArgument),
+      @"DEADLINE_EXCEEDED" : @(FIRFunctionsErrorCodeDeadlineExceeded),
+      @"NOT_FOUND" : @(FIRFunctionsErrorCodeNotFound),
+      @"ALREADY_EXISTS" : @(FIRFunctionsErrorCodeAlreadyExists),
+      @"PERMISSION_DENIED" : @(FIRFunctionsErrorCodePermissionDenied),
+      @"RESOURCE_EXHAUSTED" : @(FIRFunctionsErrorCodeResourceExhausted),
+      @"FAILED_PRECONDITION" : @(FIRFunctionsErrorCodeFailedPrecondition),
+      @"ABORTED" : @(FIRFunctionsErrorCodeAborted),
+      @"OUT_OF_RANGE" : @(FIRFunctionsErrorCodeOutOfRange),
+      @"UNIMPLEMENTED" : @(FIRFunctionsErrorCodeUnimplemented),
+      @"INTERNAL" : @(FIRFunctionsErrorCodeInternal),
+      @"UNAVAILABLE" : @(FIRFunctionsErrorCodeUnavailable),
+      @"DATA_LOSS" : @(FIRFunctionsErrorCodeDataLoss),
+      @"UNAUTHENTICATED" : @(FIRFunctionsErrorCodeUnauthenticated),
+    };
+  });
+  NSNumber *code = errors[name];
+  if (code) {
+    return code.intValue;
+  }
+  return FIRFunctionsErrorCodeInternal;
+}
+
+/**
+ * Takes a FIRFunctionsErrorCode and returns an English description of it.
+ * @param code An error code.
+ * @return A description of the code, or "UNKNOWN" if none.
+ */
+NSString *FUNDescriptionForErrorCode(FIRFunctionsErrorCode code) {
+  switch (code) {
+    case FIRFunctionsErrorCodeOK:
+      return @"OK";
+    case FIRFunctionsErrorCodeCancelled:
+      return @"CANCELLED";
+    case FIRFunctionsErrorCodeUnknown:
+      return @"UNKNOWN";
+    case FIRFunctionsErrorCodeInvalidArgument:
+      return @"INVALID ARGUMENT";
+    case FIRFunctionsErrorCodeDeadlineExceeded:
+      return @"DEADLINE EXCEEDED";
+    case FIRFunctionsErrorCodeNotFound:
+      return @"NOT FOUND";
+    case FIRFunctionsErrorCodeAlreadyExists:
+      return @"ALREADY EXISTS";
+    case FIRFunctionsErrorCodePermissionDenied:
+      return @"PERMISSION DENIED";
+    case FIRFunctionsErrorCodeResourceExhausted:
+      return @"RESOURCE EXHAUSTED";
+    case FIRFunctionsErrorCodeFailedPrecondition:
+      return @"FAILED PRECONDITION";
+    case FIRFunctionsErrorCodeAborted:
+      return @"ABORTED";
+    case FIRFunctionsErrorCodeOutOfRange:
+      return @"OUT OF RANGE";
+    case FIRFunctionsErrorCodeUnimplemented:
+      return @"UNIMPLEMENTED";
+    case FIRFunctionsErrorCodeInternal:
+      return @"INTERNAL";
+    case FIRFunctionsErrorCodeUnavailable:
+      return @"UNAVAILABLE";
+    case FIRFunctionsErrorCodeDataLoss:
+      return @"DATA LOSS";
+    case FIRFunctionsErrorCodeUnauthenticated:
+      return @"UNAUTHENTICATED";
+  }
+  return @"UNKNOWN";
+}
+
+NSError *FUNErrorForResponse(NSInteger status, NSData *_Nullable body, FUNSerializer *serializer) {
+  // Start with reasonable defaults from the status code.
+  FIRFunctionsErrorCode code = FIRFunctionsErrorCodeForHTTPStatus(status);
+  NSString *description = FUNDescriptionForErrorCode(code);
+  id details = nil;
+
+  // Then look through the body for explicit details.
+  if (body) {
+    NSError *parseError = nil;
+    id json = [NSJSONSerialization JSONObjectWithData:body options:0 error:&parseError];
+    if (!parseError && [json isKindOfClass:[NSDictionary class]]) {
+      id errorDetails = json[@"error"];
+      if ([errorDetails isKindOfClass:[NSDictionary class]]) {
+        if ([errorDetails[@"status"] isKindOfClass:[NSString class]]) {
+          code = FIRFunctionsErrorCodeForName(errorDetails[@"status"]);
+          // The default description needs to be updated for the new code.
+          description = FUNDescriptionForErrorCode(code);
+        }
+        if ([errorDetails[@"message"] isKindOfClass:[NSString class]]) {
+          description = (NSString *)errorDetails[@"message"];
+        }
+        details = errorDetails[@"details"];
+        if (details) {
+          NSError *decodeError = nil;
+          details = [serializer decode:details error:&decodeError];
+          // Just ignore the details if there an error decoding them.
+        }
+      }
+    }
+  }
+
+  if (code == FIRFunctionsErrorCodeOK) {
+    // Technically, there's an edge case where a developer could explicitly return an error code of
+    // OK, and we will treat it as success, but that seems reasonable.
+    return nil;
+  }
+
+  NSMutableDictionary *userInfo = [NSMutableDictionary dictionary];
+  userInfo[NSLocalizedDescriptionKey] = description;
+  if (details) {
+    userInfo[FIRFunctionsErrorDetailsKey] = details;
+  }
+  return [NSError errorWithDomain:FIRFunctionsErrorDomain code:code userInfo:userInfo];
+}
+
+NS_ASSUME_NONNULL_END