Array Transforms public API and parsing

This includes the new FIRFieldValue sentinels, the FSTUserDataConverter code to parse them into internal ArrayTransform operations for use in an FSTTransformMutation, and some sanity testing in FSTMutationTests.

I still need to implement FSTTransformMutation support for local application and serialization (and then integration tests).

1 files changed, 42 insertions, 3 deletions

diff --git a/Firestore/Source/API/FSTUserDataConverter.mm b/Firestore/Source/API/FSTUserDataConverter.mm
index dff9235..90d68d8 100644
--- a/Firestore/Source/API/FSTUserDataConverter.mm
+++ b/Firestore/Source/API/FSTUserDataConverter.mm
@@ -44,6 +44,7 @@
 #include "absl/memory/memory.h"
 
 namespace util = firebase::firestore::util;
+using firebase::firestore::model::ArrayTransform;
 using firebase::firestore::model::DatabaseId;
 using firebase::firestore::model::DocumentKey;
 using firebase::firestore::model::FieldMask;
@@ -165,7 +166,11 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
   FSTUserDataSourceSet,
   FSTUserDataSourceMergeSet,
   FSTUserDataSourceUpdate,
-  FSTUserDataSourceQueryValue,  // from a where clause or cursor bound.
+  /**
+   * Indicates the source is a where clause, cursor bound, arrayUnion() element, etc. In particular,
+   * this will result in [FSTParseContext isWrite] returning NO.
+   */
+  FSTUserDataSourceArgument,
 };
 
 #pragma mark - FSTParseContext
@@ -318,7 +323,7 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
     case FSTUserDataSourceMergeSet:  // Falls through.
     case FSTUserDataSourceUpdate:
       return YES;
-    case FSTUserDataSourceQueryValue:
+    case FSTUserDataSourceArgument:
       return NO;
     default:
       FSTThrowInvalidArgument(@"Unexpected case for FSTUserDataSource: %d", self.dataSource);
@@ -489,7 +494,7 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
 
 - (FSTFieldValue *)parsedQueryValue:(id)input {
   FSTParseContext *context =
-      [FSTParseContext contextWithSource:FSTUserDataSourceQueryValue
+      [FSTParseContext contextWithSource:FSTUserDataSourceArgument
                                     path:absl::make_unique<FieldPath>(FieldPath::EmptyPath())];
   FSTFieldValue *_Nullable parsed = [self parseData:input context:context];
   FSTAssert(parsed, @"Parsed data should not be nil.");
@@ -593,10 +598,28 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
           @"SetOptions.merge()%@",
           [context fieldDescription]);
     }
+
   } else if ([fieldValue isKindOfClass:[FSTServerTimestampFieldValue class]]) {
     [context appendToFieldTransformsWithFieldPath:*context.path
                                transformOperation:absl::make_unique<ServerTimestampTransform>(
                                                       ServerTimestampTransform::Get())];
+
+  } else if ([fieldValue isKindOfClass:[FSTArrayUnionFieldValue class]]) {
+    std::vector<FSTFieldValue *> parsedElements =
+        [self parseArrayTransformElements:((FSTArrayUnionFieldValue *)fieldValue).elements];
+    auto array_union =
+        absl::make_unique<ArrayTransform>(TransformOperation::Type::ArrayUnion, parsedElements);
+    [context appendToFieldTransformsWithFieldPath:*context.path
+                               transformOperation:std::move(array_union)];
+
+  } else if ([fieldValue isKindOfClass:[FSTArrayRemoveFieldValue class]]) {
+    std::vector<FSTFieldValue *> parsedElements =
+        [self parseArrayTransformElements:((FSTArrayRemoveFieldValue *)fieldValue).elements];
+    auto array_remove =
+        absl::make_unique<ArrayTransform>(TransformOperation::Type::ArrayRemove, parsedElements);
+    [context appendToFieldTransformsWithFieldPath:*context.path
+                               transformOperation:std::move(array_remove)];
+
   } else {
     FSTFail(@"Unknown FIRFieldValue type: %@", NSStringFromClass([fieldValue class]));
   }
@@ -753,6 +776,22 @@ typedef NS_ENUM(NSInteger, FSTUserDataSource) {
   }
 }
 
+- (std::vector<FSTFieldValue *>)parseArrayTransformElements:(NSArray<id> *)elements {
+  std::vector<FSTFieldValue *> results;
+  for (id element in elements) {
+    // Although array transforms are used with writes, the actual elements being unioned or removed
+    // are not considered writes since they cannot contain any FieldValue sentinels, etc.
+    FSTParseContext *context =
+        [FSTParseContext contextWithSource:FSTUserDataSourceArgument
+                                      path:absl::make_unique<FieldPath>(FieldPath::EmptyPath())];
+    FSTFieldValue *parsedElement = [self parseData:element context:context];
+    FSTAssert(parsedElement && context.fieldTransforms->size() == 0,
+              @"Failed to properly parse array transform element: %@", element);
+    results.push_back(parsedElement);
+  }
+  return results;
+}
+
 @end
 
 NS_ASSUME_NONNULL_END