Array Contains Queries (not added to public headers yet). (#1138)

5 files changed, 76 insertions, 5 deletions

diff --git a/Firestore/Source/API/FIRQuery+Internal.h b/Firestore/Source/API/FIRQuery+Internal.h
index 3c2b2a7..c4f9f23 100644
--- a/Firestore/Source/API/FIRQuery+Internal.h
+++ b/Firestore/Source/API/FIRQuery+Internal.h
@@ -23,7 +23,42 @@ NS_ASSUME_NONNULL_BEGIN
 /** Internal FIRQuery API we don't want exposed in our public header files. */
 @interface FIRQuery (Internal)
 + (FIRQuery *)referenceWithQuery:(FSTQuery *)query firestore:(FIRFirestore *)firestore;
+
 @property(nonatomic, strong, readonly) FSTQuery *query;
+
+@end
+
+// TODO(array-features): Move to FIRQuery.h once backend support is available.
+@interface FIRQuery ()
+
+/**
+ * Creates and returns a new `FIRQuery` with the additional filter that documents must contain
+ * the specified field, it must be an array, and the array must contain the provided value.
+ *
+ * @param field The name of the field containing an array to search
+ * @param value The value that must be contained in the array
+ *
+ * @return The created `FIRQuery`.
+ */
+// clang-format off
+- (FIRQuery *)queryWhereField:(NSString *)field
+                arrayContains:(id)value NS_SWIFT_NAME(whereField(_:arrayContains:));
+// clang-format on
+
+/**
+ * Creates and returns a new `FIRQuery` with the additional filter that documents must contain
+ * the specified field, it must be an array, and the array must contain the provided value.
+ *
+ * @param path The path of the field containing an array to search
+ * @param value The value that must be contained in the array
+ *
+ * @return The created `FIRQuery`.
+ */
+// clang-format off
+- (FIRQuery *)queryWhereFieldPath:(FIRFieldPath *)path
+                    arrayContains:(id)value NS_SWIFT_NAME(whereField(_:arrayContains:));
+// clang-format on
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Firestore/Source/API/FIRQuery.mm b/Firestore/Source/API/FIRQuery.mm
index 2d78ac0..32d8327 100644
--- a/Firestore/Source/API/FIRQuery.mm
+++ b/Firestore/Source/API/FIRQuery.mm
@@ -238,6 +238,17 @@ addSnapshotListenerInternalWithOptions:(FSTListenOptions *)internalOptions
                                  value:value];
 }
 
+- (FIRQuery *)queryWhereField:(NSString *)field arrayContains:(id)value {
+  return
+      [self queryWithFilterOperator:FSTRelationFilterOperatorArrayContains field:field value:value];
+}
+
+- (FIRQuery *)queryWhereFieldPath:(FIRFieldPath *)path arrayContains:(id)value {
+  return [self queryWithFilterOperator:FSTRelationFilterOperatorArrayContains
+                                  path:path.internalValue
+                                 value:value];
+}
+
 - (FIRQuery *)queryWhereField:(NSString *)field isGreaterThanOrEqualTo:(id)value {
   return [self queryWithFilterOperator:FSTRelationFilterOperatorGreaterThanOrEqual
                                  field:field
@@ -443,6 +454,11 @@ addSnapshotListenerInternalWithOptions:(FSTListenOptions *)internalOptions
                                 value:(id)value {
   FSTFieldValue *fieldValue;
   if (fieldPath.IsKeyFieldPath()) {
+    if (filterOperator == FSTRelationFilterOperatorArrayContains) {
+      FSTThrowInvalidArgument(
+          @"Invalid query. You can't do arrayContains queries on document ID since document IDs "
+          @"are not arrays.");
+    }
     if ([value isKindOfClass:[NSString class]]) {
       NSString *documentKey = (NSString *)value;
       if ([documentKey containsString:@"/"]) {
diff --git a/Firestore/Source/Core/FSTQuery.h b/Firestore/Source/Core/FSTQuery.h
index 3a67e7f..572fabb 100644
--- a/Firestore/Source/Core/FSTQuery.h
+++ b/Firestore/Source/Core/FSTQuery.h
@@ -34,6 +34,7 @@ typedef NS_ENUM(NSInteger, FSTRelationFilterOperator) {
   FSTRelationFilterOperatorEqual,
   FSTRelationFilterOperatorGreaterThanOrEqual,
   FSTRelationFilterOperatorGreaterThan,
+  FSTRelationFilterOperatorArrayContains,
 };
 
 /** Interface used for all query filters. */
diff --git a/Firestore/Source/Core/FSTQuery.mm b/Firestore/Source/Core/FSTQuery.mm
index 8f49c26..0cd11e8 100644
--- a/Firestore/Source/Core/FSTQuery.mm
+++ b/Firestore/Source/Core/FSTQuery.mm
@@ -58,6 +58,8 @@ NSString *FSTStringFromQueryRelationOperator(FSTRelationFilterOperator filterOpe
       return @">=";
     case FSTRelationFilterOperatorGreaterThan:
       return @">";
+    case FSTRelationFilterOperatorArrayContains:
+      return @"array_contains";
     default:
       FSTCFail(@"Unknown FSTRelationFilterOperator %lu", (unsigned long)filterOperator);
   }
@@ -119,7 +121,8 @@ NSString *FSTStringFromQueryRelationOperator(FSTRelationFilterOperator filterOpe
 #pragma mark - Public Methods
 
 - (BOOL)isInequality {
-  return self.filterOperator != FSTRelationFilterOperatorEqual;
+  return self.filterOperator != FSTRelationFilterOperatorEqual &&
+         self.filterOperator != FSTRelationFilterOperatorArrayContains;
 }
 
 - (const firebase::firestore::model::FieldPath &)field {
@@ -150,6 +153,8 @@ NSString *FSTStringFromQueryRelationOperator(FSTRelationFilterOperator filterOpe
   if (_field.IsKeyFieldPath()) {
     FSTAssert([self.value isKindOfClass:[FSTReferenceValue class]],
               @"Comparing on key, but filter value not a FSTReferenceValue.");
+    FSTAssert(self.filterOperator != FSTRelationFilterOperatorArrayContains,
+              @"arrayContains queries don't make sense on document keys.");
     FSTReferenceValue *refValue = (FSTReferenceValue *)self.value;
     NSComparisonResult comparison = FSTDocumentKeyComparator(document.key, refValue.value);
     return [self matchesComparison:comparison];
@@ -180,9 +185,19 @@ NSString *FSTStringFromQueryRelationOperator(FSTRelationFilterOperator filterOpe
 
 /** Returns YES if receiver is true with the given value as its LHS. */
 - (BOOL)matchesValue:(FSTFieldValue *)other {
-  // Only compare types with matching backend order (such as double and int).
-  return self.value.typeOrder == other.typeOrder &&
-         [self matchesComparison:[other compare:self.value]];
+  if (self.filterOperator == FSTRelationFilterOperatorArrayContains) {
+    if ([other isMemberOfClass:[FSTArrayValue class]]) {
+      FSTArrayValue *arrayValue = (FSTArrayValue *)other;
+      return [arrayValue.internalValue containsObject:self.value];
+    } else {
+      return false;
+    }
+  } else {
+    // Only perform comparison queries on types with matching backend order (such as double and
+    // int).
+    return self.value.typeOrder == other.typeOrder &&
+           [self matchesComparison:[other compare:self.value]];
+  }
 }
 
 - (BOOL)matchesComparison:(NSComparisonResult)comparison {
@@ -701,7 +716,7 @@ NSString *FSTStringFromQueryRelationOperator(FSTRelationFilterOperator filterOpe
 - (const FieldPath *)inequalityFilterField {
   for (id<FSTFilter> filter in self.filters) {
     if ([filter isKindOfClass:[FSTRelationFilter class]] &&
-        ((FSTRelationFilter *)filter).filterOperator != FSTRelationFilterOperatorEqual) {
+        ((FSTRelationFilter *)filter).isInequality) {
       return &filter.field;
     }
   }
diff --git a/Firestore/Source/Remote/FSTSerializerBeta.mm b/Firestore/Source/Remote/FSTSerializerBeta.mm
index ebb49a7..5cbfecc 100644
--- a/Firestore/Source/Remote/FSTSerializerBeta.mm
+++ b/Firestore/Source/Remote/FSTSerializerBeta.mm
@@ -952,6 +952,8 @@ NS_ASSUME_NONNULL_BEGIN
       return GCFSStructuredQuery_FieldFilter_Operator_GreaterThanOrEqual;
     case FSTRelationFilterOperatorGreaterThan:
       return GCFSStructuredQuery_FieldFilter_Operator_GreaterThan;
+    case FSTRelationFilterOperatorArrayContains:
+      return GCFSStructuredQuery_FieldFilter_Operator_ArrayContains;
     default:
       FSTFail(@"Unhandled FSTRelationFilterOperator: %ld", (long)filterOperator);
   }
@@ -970,6 +972,8 @@ NS_ASSUME_NONNULL_BEGIN
       return FSTRelationFilterOperatorGreaterThanOrEqual;
     case GCFSStructuredQuery_FieldFilter_Operator_GreaterThan:
       return FSTRelationFilterOperatorGreaterThan;
+    case GCFSStructuredQuery_FieldFilter_Operator_ArrayContains:
+      return FSTRelationFilterOperatorArrayContains;
     default:
       FSTFail(@"Unhandled FieldFilter.operator: %d", filterOperator);
   }