Add new comparators: Exists and NotExists (#33)

.golangci.yml

@@ -2,6 +2,7 @@ linters:
   enable:
     - errname
     - errorlint
+    - goerr113
     - lll
     - stylecheck
 linters-settings:

examples/getting-started/main.go

@@ -12,7 +12,7 @@ import (
 // Replace these values with your own connection option. This connection option is hard-coded for easy
 // demonstration. Make sure not to hard-code the credentials in the production code.
 const (
-	connectionString = "mongodb://lineman:lineman@localhost:27017"
+	connectionString = "mongodb://admin:password@localhost:27017"
 	databaseName     = "repogen_examples"
 	collectionName   = "gettingstarted_user"
 )

examples/getting-started/user.go

@@ -16,27 +16,32 @@ type UserModel struct {
 
 //go:generate repogen -src=user.go -dest=user_repo.go -model=UserModel -repo=UserRepository
 
-// UserRepository is an interface that describes the specification of querying user data in the database
+// UserRepository is an interface that describes the specification of querying
+// user data in the database.
 type UserRepository interface {
-	// InsertOne stores userModel into the database and returns inserted ID if insertion
-	// succeeds and returns error if insertion fails.
+	// InsertOne stores userModel into the database and returns inserted ID
+	// if insertion succeeds and returns error if insertion fails.
 	InsertOne(ctx context.Context, userModel *UserModel) (interface{}, error)
 
-	// FindByUsername queries user by username. If a user with specified username exists,
-	// the user will be returned. Otherwise, error will be returned.
+	// FindByUsername queries user by username. If a user with specified
+	// username exists, the user will be returned. Otherwise, error will be
+	// returned.
 	FindByUsername(ctx context.Context, username string) (*UserModel, error)
 
-	// UpdateDisplayNameByID updates a user with the specified ID with a new display name.
-	// If there is a user matches the query, it will return true. Error will be returned
-	// only when error occurs while accessing the database.
+	// UpdateDisplayNameByID updates a user with the specified ID with a new
+	// display name. If there is a user matches the query, it will return
+	// true. Error will be returned only when error occurs while accessing
+	// the database.
 	UpdateDisplayNameByID(ctx context.Context, displayName string, id primitive.ObjectID) (bool, error)
 
-	// DeleteByCity deletes users that have `city` value match the parameter and returns
-	// the match count. The error will be returned only when error occurs while accessing
-	// the database. This is a MANY mode because the first return type is an integer.
+	// DeleteByCity deletes users that have `city` value match the parameter
+	// and returns the match count. The error will be returned only when
+	// error occurs while accessing the database. This is a MANY mode
+	// because the first return type is an integer.
 	DeleteByCity(ctx context.Context, city string) (int, error)
 
-	// CountByCity returns the number of rows that match the given city parameter. If an
-	// error occurs while accessing the database, error value will be returned.
+	// CountByCity returns the number of rows that match the given city
+	// parameter. If an error occurs while accessing the database, error
+	// value will be returned.
 	CountByCity(ctx context.Context, city string) (int, error)
 }

internal/mongo/generator_test.go

@@ -34,6 +34,11 @@ var (
 		Type: code.SimpleType("NameModel"),
 		Tags: map[string][]string{"bson": {"name"}},
 	}
+	referrerField = code.StructField{
+		Name: "Referrer",
+		Type: code.PointerType{ContainedType: code.SimpleType("UserModel")},
+		Tags: map[string][]string{"bson": {"referrer"}},
+	}
 	consentHistoryField = code.StructField{
 		Name: "ConsentHistory",
 		Type: code.ArrayType{ContainedType: code.SimpleType("ConsentHistory")},
@@ -68,6 +73,7 @@ var userModel = code.Struct{
 		genderField,
 		ageField,
 		nameField,
+		referrerField,
 		consentHistoryField,
 		enabledField,
 		accessTokenField,
@@ -882,6 +888,80 @@ func TestGenerateMethod_Find(t *testing.T) {
 	if err := cursor.All(arg0, &entities); err != nil {
 		return nil, err
 	}
+	return entities, nil`,
+		},
+		{
+			Name: "find with Exists comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "FindByReferrerExists",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.TypeError,
+				},
+				Operation: spec.FindOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{
+								Comparator:     spec.ComparatorExists,
+								FieldReference: spec.FieldReference{referrerField},
+								ParamIndex:     1,
+							},
+						},
+					},
+				},
+			},
+			ExpectedBody: `	cursor, err := r.collection.Find(arg0, bson.M{
+		"referrer": bson.M{"$exists": 1},
+	}, options.Find().SetSort(bson.M{
+	}))
+	if err != nil {
+		return nil, err
+	}
+	var entities []*UserModel
+	if err := cursor.All(arg0, &entities); err != nil {
+		return nil, err
+	}
+	return entities, nil`,
+		},
+		{
+			Name: "find with NotExists comparator",
+			MethodSpec: spec.MethodSpec{
+				Name: "FindByReferrerNotExists",
+				Params: []code.Param{
+					{Name: "ctx", Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.TypeError,
+				},
+				Operation: spec.FindOperation{
+					Mode: spec.QueryModeMany,
+					Query: spec.QuerySpec{
+						Predicates: []spec.Predicate{
+							{
+								Comparator:     spec.ComparatorNotExists,
+								FieldReference: spec.FieldReference{referrerField},
+								ParamIndex:     1,
+							},
+						},
+					},
+				},
+			},
+			ExpectedBody: `	cursor, err := r.collection.Find(arg0, bson.M{
+		"referrer": bson.M{"$exists": 0},
+	}, options.Find().SetSort(bson.M{
+	}))
+	if err != nil {
+		return nil, err
+	}
+	var entities []*UserModel
+	if err := cursor.All(arg0, &entities); err != nil {
+		return nil, err
+	}
 	return entities, nil`,
 		},
 		{

internal/mongo/models.go

@@ -109,6 +109,10 @@ func (p predicate) Code() string {
 		return fmt.Sprintf(`"%s": true`, p.Field)
 	case spec.ComparatorFalse:
 		return fmt.Sprintf(`"%s": false`, p.Field)
+	case spec.ComparatorExists:
+		return fmt.Sprintf(`"%s": bson.M{"$exists": 1}`, p.Field)
+	case spec.ComparatorNotExists:
+		return fmt.Sprintf(`"%s": bson.M{"$exists": 0}`, p.Field)
 	}
 	return ""
 }

internal/spec/parser_test.go

@@ -583,6 +583,52 @@ func TestParseInterfaceMethod_Find(t *testing.T) {
 				}},
 			},
 		},
+		{
+			Name: "FindByArgExists method",
+			Method: code.Method{
+				Name: "FindByReferrerExists",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.TypeError,
+				},
+			},
+			ExpectedOperation: spec.FindOperation{
+				Mode: spec.QueryModeMany,
+				Query: spec.QuerySpec{Predicates: []spec.Predicate{
+					{
+						FieldReference: spec.FieldReference{referrerField},
+						Comparator:     spec.ComparatorExists,
+						ParamIndex:     1,
+					},
+				}},
+			},
+		},
+		{
+			Name: "FindByArgNotExists method",
+			Method: code.Method{
+				Name: "FindByReferrerNotExists",
+				Params: []code.Param{
+					{Type: code.ExternalType{PackageAlias: "context", Name: "Context"}},
+				},
+				Returns: []code.Type{
+					code.ArrayType{ContainedType: code.PointerType{ContainedType: code.SimpleType("UserModel")}},
+					code.TypeError,
+				},
+			},
+			ExpectedOperation: spec.FindOperation{
+				Mode: spec.QueryModeMany,
+				Query: spec.QuerySpec{Predicates: []spec.Predicate{
+					{
+						FieldReference: spec.FieldReference{referrerField},
+						Comparator:     spec.ComparatorNotExists,
+						ParamIndex:     1,
+					},
+				}},
+			},
+		},
 		{
 			Name: "FindByArgOrderByArg method",
 			Method: code.Method{

internal/spec/query.go

@@ -44,6 +44,8 @@ const (
 	ComparatorNotIn            Comparator = "NOT_IN"
 	ComparatorTrue             Comparator = "EQUAL_TRUE"
 	ComparatorFalse            Comparator = "EQUAL_FALSE"
+	ComparatorExists           Comparator = "EXISTS"
+	ComparatorNotExists        Comparator = "NOT_EXISTS"
 )
 
 // ArgumentTypeFromFieldType returns a type of required argument from the given
@@ -63,7 +65,7 @@ func (c Comparator) NumberOfArguments() int {
 	switch c {
 	case ComparatorBetween:
 		return 2
-	case ComparatorTrue, ComparatorFalse:
+	case ComparatorTrue, ComparatorFalse, ComparatorExists, ComparatorNotExists:
 		return 0
 	default:
 		return 1
@@ -82,7 +84,9 @@ type queryParser struct {
 	StructModel   code.Struct
 }
 
-func (p queryParser) parseQuery(rawTokens []string, paramIndex int) (QuerySpec, error) {
+func (p queryParser) parseQuery(rawTokens []string, paramIndex int) (QuerySpec,
+	error) {
+
 	if len(rawTokens) == 0 {
 		return QuerySpec{}, ErrQueryRequired
 	}
@@ -154,7 +158,9 @@ func (p queryParser) splitPredicateTokens(tokens []string) (Operator, [][]string
 	return operator, predicateTokens, nil
 }
 
-func (p queryParser) parsePredicate(t []string, paramIndex int) (Predicate, error) {
+func (p queryParser) parsePredicate(t []string, paramIndex int) (Predicate,
+	error) {
+
 	if len(t) > 1 && t[len(t)-1] == "Not" {
 		return p.createPredicate(t[:len(t)-1], ComparatorNot, paramIndex)
 	}
@@ -173,6 +179,9 @@ func (p queryParser) parsePredicate(t []string, paramIndex int) (Predicate, erro
 	if len(t) > 2 && t[len(t)-2] == "Not" && t[len(t)-1] == "In" {
 		return p.createPredicate(t[:len(t)-2], ComparatorNotIn, paramIndex)
 	}
+	if len(t) > 2 && t[len(t)-2] == "Not" && t[len(t)-1] == "Exists" {
+		return p.createPredicate(t[:len(t)-2], ComparatorNotExists, paramIndex)
+	}
 	if len(t) > 1 && t[len(t)-1] == "In" {
 		return p.createPredicate(t[:len(t)-1], ComparatorIn, paramIndex)
 	}
@@ -185,10 +194,15 @@ func (p queryParser) parsePredicate(t []string, paramIndex int) (Predicate, erro
 	if len(t) > 1 && t[len(t)-1] == "False" {
 		return p.createPredicate(t[:len(t)-1], ComparatorFalse, paramIndex)
 	}
+	if len(t) > 1 && t[len(t)-1] == "Exists" {
+		return p.createPredicate(t[:len(t)-1], ComparatorExists, paramIndex)
+	}
 	return p.createPredicate(t, ComparatorEqual, paramIndex)
 }
 
-func (p queryParser) createPredicate(t []string, comparator Comparator, paramIndex int) (Predicate, error) {
+func (p queryParser) createPredicate(t []string, comparator Comparator,
+	paramIndex int) (Predicate, error) {
+
 	fields, ok := p.fieldResolver.ResolveStructField(p.StructModel, t)
 	if !ok {
 		return Predicate{}, NewStructFieldNotFoundError(t)

internal/testutils/multilines.go

@@ -5,6 +5,60 @@ import (
 	"strings"
 )
 
+// lineMismatchedError is an error indicating unmatched line when comparing
+// string using ExpectMultiLineString.
+type lineMismatchedError struct {
+	LineNumber int
+	Expected   string
+	Received   string
+}
+
+// NewLineMismatchedError is a constructor for lineMismatchedError.
+func NewLineMismatchedError(lineNumber int, expected, received string) error {
+	return lineMismatchedError{
+		LineNumber: lineNumber,
+		Expected:   expected,
+		Received:   received,
+	}
+}
+
+func (err lineMismatchedError) Error() string {
+	return fmt.Sprintf("at line %d\nexpected: %v\nreceived: %v", err.LineNumber,
+		err.Expected, err.Received)
+}
+
+type missingLinesError struct {
+	MissingLines []string
+}
+
+// NewMissingLinesError is a constructor for missingLinesError.
+func NewMissingLinesError(missingLines []string) error {
+	return missingLinesError{
+		MissingLines: missingLines,
+	}
+}
+
+func (err missingLinesError) Error() string {
+	return fmt.Sprintf("missing lines:\n%s",
+		strings.Join(err.MissingLines, "\n"))
+}
+
+type unexpectedLinesError struct {
+	UnexpectedLines []string
+}
+
+// NewUnexpectedLinesError is a constructor for unexpectedLinesError.
+func NewUnexpectedLinesError(unexpectedLines []string) error {
+	return unexpectedLinesError{
+		UnexpectedLines: unexpectedLines,
+	}
+}
+
+func (err unexpectedLinesError) Error() string {
+	return fmt.Sprintf("unexpected lines:\n%s",
+		strings.Join(err.UnexpectedLines, "\n"))
+}
+
 // ExpectMultiLineString compares two multi-line strings and report the
 // difference.
 func ExpectMultiLineString(expected, actual string) error {
@@ -18,14 +72,14 @@ func ExpectMultiLineString(expected, actual string) error {
 
 	for i := 0; i < numberOfComparableLines; i++ {
 		if expectedLines[i] != actualLines[i] {
-			return fmt.Errorf("at line %d\nexpected: %v\nreceived: %v", i+1, expectedLines[i], actualLines[i])
+			return NewLineMismatchedError(i+1, expectedLines[i], actualLines[i])
 		}
 	}
 
 	if len(expectedLines) < len(actualLines) {
-		return fmt.Errorf("unexpected lines:\n%s", strings.Join(actualLines[len(expectedLines):], "\n"))
+		return NewUnexpectedLinesError(actualLines[len(expectedLines):])
 	} else if len(expectedLines) > len(actualLines) {
-		return fmt.Errorf("missing lines:\n%s", strings.Join(expectedLines[len(actualLines):], "\n"))
+		return NewMissingLinesError(expectedLines[len(actualLines):])
 	}
 
 	return nil

main.go

@@ -96,15 +96,20 @@ func generateFromRequest(pkgDir, structModelName, repositoryInterfaceName string
 	return generateRepository(pkg, structModelName, repositoryInterfaceName)
 }
 
+var (
+	errStructNotFound    = errors.New("struct not found")
+	errInterfaceNotFound = errors.New("interface not found")
+)
+
 func generateRepository(pkg code.Package, structModelName, repositoryInterfaceName string) (string, error) {
 	structModel, ok := pkg.Structs[structModelName]
 	if !ok {
-		return "", errors.New("struct model not found")
+		return "", errStructNotFound
 	}
 
 	intf, ok := pkg.Interfaces[repositoryInterfaceName]
 	if !ok {
-		return "", errors.New("interface model not found")
+		return "", errInterfaceNotFound
 	}
 
 	var methodSpecs []spec.MethodSpec