entc/gen: lazy compute storage-driver queries (#408)

examples/edgeindex/ent/city_query.go

@@ -31,8 +31,9 @@ type CityQuery struct {
 	predicates []predicate.City
 	// eager-loading edges.
 	withStreets *StreetQuery
-	// intermediate query.
-	sql *sql.Selector
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
 }
 
 // Where adds a new predicate for the builder.
@@ -62,12 +63,18 @@ func (cq *CityQuery) Order(o ...Order) *CityQuery {
 // QueryStreets chains the current query on the streets edge.
 func (cq *CityQuery) QueryStreets() *StreetQuery {
 	query := &StreetQuery{config: cq.config}
-	step := sqlgraph.NewStep(
-		sqlgraph.From(city.Table, city.FieldID, cq.sqlQuery()),
-		sqlgraph.To(street.Table, street.FieldID),
-		sqlgraph.Edge(sqlgraph.O2M, false, city.StreetsTable, city.StreetsColumn),
-	)
-	query.sql = sqlgraph.SetNeighbors(cq.driver.Dialect(), step)
+	query.path = func(ctx context.Context) (fromU *sql.Selector, err error) {
+		if err := cq.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		step := sqlgraph.NewStep(
+			sqlgraph.From(city.Table, city.FieldID, cq.sqlQuery()),
+			sqlgraph.To(street.Table, street.FieldID),
+			sqlgraph.Edge(sqlgraph.O2M, false, city.StreetsTable, city.StreetsColumn),
+		)
+		fromU = sqlgraph.SetNeighbors(cq.driver.Dialect(), step)
+		return fromU, nil
+	}
 	return query
 }
 
@@ -167,6 +174,9 @@ func (cq *CityQuery) OnlyXID(ctx context.Context) int {
 
 // All executes the query and returns a list of Cities.
 func (cq *CityQuery) All(ctx context.Context) ([]*City, error) {
+	if err := cq.prepareQuery(ctx); err != nil {
+		return nil, err
+	}
 	return cq.sqlAll(ctx)
 }
 
@@ -199,6 +209,9 @@ func (cq *CityQuery) IDsX(ctx context.Context) []int {
 
 // Count returns the count of the given query.
 func (cq *CityQuery) Count(ctx context.Context) (int, error) {
+	if err := cq.prepareQuery(ctx); err != nil {
+		return 0, err
+	}
 	return cq.sqlCount(ctx)
 }
 
@@ -213,6 +226,9 @@ func (cq *CityQuery) CountX(ctx context.Context) int {
 
 // Exist returns true if the query has elements in the graph.
 func (cq *CityQuery) Exist(ctx context.Context) (bool, error) {
+	if err := cq.prepareQuery(ctx); err != nil {
+		return false, err
+	}
 	return cq.sqlExist(ctx)
 }
 
@@ -236,7 +252,8 @@ func (cq *CityQuery) Clone() *CityQuery {
 		unique:     append([]string{}, cq.unique...),
 		predicates: append([]predicate.City{}, cq.predicates...),
 		// clone intermediate query.
-		sql: cq.sql.Clone(),
+		sql:  cq.sql.Clone(),
+		path: cq.path,
 	}
 }
 
@@ -269,7 +286,12 @@ func (cq *CityQuery) WithStreets(opts ...func(*StreetQuery)) *CityQuery {
 func (cq *CityQuery) GroupBy(field string, fields ...string) *CityGroupBy {
 	group := &CityGroupBy{config: cq.config}
 	group.fields = append([]string{field}, fields...)
-	group.sql = cq.sqlQuery()
+	group.path = func(ctx context.Context) (prev *sql.Selector, err error) {
+		if err := cq.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		return cq.sqlQuery(), nil
+	}
 	return group
 }
 
@@ -288,10 +310,27 @@ func (cq *CityQuery) GroupBy(field string, fields ...string) *CityGroupBy {
 func (cq *CityQuery) Select(field string, fields ...string) *CitySelect {
 	selector := &CitySelect{config: cq.config}
 	selector.fields = append([]string{field}, fields...)
-	selector.sql = cq.sqlQuery()
+	selector.path = func(ctx context.Context) (prev *sql.Selector, err error) {
+		if err := cq.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		return cq.sqlQuery(), nil
+	}
 	return selector
 }
 
+func (cq *CityQuery) prepareQuery(ctx context.Context) error {
+	if cq.path != nil {
+		prev, err := cq.path(ctx)
+		if err != nil {
+			return err
+		}
+		cq.sql = prev
+	}
+	// Privacy and query checks go here.
+	return nil
+}
+
 func (cq *CityQuery) sqlAll(ctx context.Context) ([]*City, error) {
 	var (
 		nodes       = []*City{}
@@ -431,8 +470,9 @@ type CityGroupBy struct {
 	config
 	fields []string
 	fns    []Aggregate
-	// intermediate query.
-	sql *sql.Selector
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
 }
 
 // Aggregate adds the given aggregation functions to the group-by query.
@@ -443,6 +483,11 @@ func (cgb *CityGroupBy) Aggregate(fns ...Aggregate) *CityGroupBy {
 
 // Scan applies the group-by query and scan the result into the given value.
 func (cgb *CityGroupBy) Scan(ctx context.Context, v interface{}) error {
+	query, err := cgb.path(ctx)
+	if err != nil {
+		return err
+	}
+	cgb.sql = query
 	return cgb.sqlScan(ctx, v)
 }
 
@@ -561,12 +606,18 @@ func (cgb *CityGroupBy) sqlQuery() *sql.Selector {
 type CitySelect struct {
 	config
 	fields []string
-	// intermediate queries.
-	sql *sql.Selector
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
 }
 
 // Scan applies the selector query and scan the result into the given value.
 func (cs *CitySelect) Scan(ctx context.Context, v interface{}) error {
+	query, err := cs.path(ctx)
+	if err != nil {
+		return err
+	}
+	cs.sql = query
 	return cs.sqlScan(ctx, v)
 }
 

examples/edgeindex/ent/client.go

@@ -190,14 +190,16 @@ func (c *CityClient) GetX(ctx context.Context, id int) *City {
 // QueryStreets queries the streets edge of a City.
 func (c *CityClient) QueryStreets(ci *City) *StreetQuery {
 	query := &StreetQuery{config: c.config}
-	id := ci.ID
-	step := sqlgraph.NewStep(
-		sqlgraph.From(city.Table, city.FieldID, id),
-		sqlgraph.To(street.Table, street.FieldID),
-		sqlgraph.Edge(sqlgraph.O2M, false, city.StreetsTable, city.StreetsColumn),
-	)
-	query.sql = sqlgraph.Neighbors(ci.driver.Dialect(), step)
-
+	query.path = func(ctx context.Context) (fromV *sql.Selector, _ error) {
+		id := ci.ID
+		step := sqlgraph.NewStep(
+			sqlgraph.From(city.Table, city.FieldID, id),
+			sqlgraph.To(street.Table, street.FieldID),
+			sqlgraph.Edge(sqlgraph.O2M, false, city.StreetsTable, city.StreetsColumn),
+		)
+		fromV = sqlgraph.Neighbors(ci.driver.Dialect(), step)
+		return fromV, nil
+	}
 	return query
 }
 
@@ -287,14 +289,16 @@ func (c *StreetClient) GetX(ctx context.Context, id int) *Street {
 // QueryCity queries the city edge of a Street.
 func (c *StreetClient) QueryCity(s *Street) *CityQuery {
 	query := &CityQuery{config: c.config}
-	id := s.ID
-	step := sqlgraph.NewStep(
-		sqlgraph.From(street.Table, street.FieldID, id),
-		sqlgraph.To(city.Table, city.FieldID),
-		sqlgraph.Edge(sqlgraph.M2O, true, street.CityTable, street.CityColumn),
-	)
-	query.sql = sqlgraph.Neighbors(s.driver.Dialect(), step)
-
+	query.path = func(ctx context.Context) (fromV *sql.Selector, _ error) {
+		id := s.ID
+		step := sqlgraph.NewStep(
+			sqlgraph.From(street.Table, street.FieldID, id),
+			sqlgraph.To(city.Table, city.FieldID),
+			sqlgraph.Edge(sqlgraph.M2O, true, street.CityTable, street.CityColumn),
+		)
+		fromV = sqlgraph.Neighbors(s.driver.Dialect(), step)
+		return fromV, nil
+	}
 	return query
 }
 

examples/edgeindex/ent/street_query.go

@@ -31,8 +31,9 @@ type StreetQuery struct {
 	// eager-loading edges.
 	withCity *CityQuery
 	withFKs  bool
-	// intermediate query.
-	sql *sql.Selector
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
 }
 
 // Where adds a new predicate for the builder.
@@ -62,12 +63,18 @@ func (sq *StreetQuery) Order(o ...Order) *StreetQuery {
 // QueryCity chains the current query on the city edge.
 func (sq *StreetQuery) QueryCity() *CityQuery {
 	query := &CityQuery{config: sq.config}
-	step := sqlgraph.NewStep(
-		sqlgraph.From(street.Table, street.FieldID, sq.sqlQuery()),
-		sqlgraph.To(city.Table, city.FieldID),
-		sqlgraph.Edge(sqlgraph.M2O, true, street.CityTable, street.CityColumn),
-	)
-	query.sql = sqlgraph.SetNeighbors(sq.driver.Dialect(), step)
+	query.path = func(ctx context.Context) (fromU *sql.Selector, err error) {
+		if err := sq.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		step := sqlgraph.NewStep(
+			sqlgraph.From(street.Table, street.FieldID, sq.sqlQuery()),
+			sqlgraph.To(city.Table, city.FieldID),
+			sqlgraph.Edge(sqlgraph.M2O, true, street.CityTable, street.CityColumn),
+		)
+		fromU = sqlgraph.SetNeighbors(sq.driver.Dialect(), step)
+		return fromU, nil
+	}
 	return query
 }
 
@@ -167,6 +174,9 @@ func (sq *StreetQuery) OnlyXID(ctx context.Context) int {
 
 // All executes the query and returns a list of Streets.
 func (sq *StreetQuery) All(ctx context.Context) ([]*Street, error) {
+	if err := sq.prepareQuery(ctx); err != nil {
+		return nil, err
+	}
 	return sq.sqlAll(ctx)
 }
 
@@ -199,6 +209,9 @@ func (sq *StreetQuery) IDsX(ctx context.Context) []int {
 
 // Count returns the count of the given query.
 func (sq *StreetQuery) Count(ctx context.Context) (int, error) {
+	if err := sq.prepareQuery(ctx); err != nil {
+		return 0, err
+	}
 	return sq.sqlCount(ctx)
 }
 
@@ -213,6 +226,9 @@ func (sq *StreetQuery) CountX(ctx context.Context) int {
 
 // Exist returns true if the query has elements in the graph.
 func (sq *StreetQuery) Exist(ctx context.Context) (bool, error) {
+	if err := sq.prepareQuery(ctx); err != nil {
+		return false, err
+	}
 	return sq.sqlExist(ctx)
 }
 
@@ -236,7 +252,8 @@ func (sq *StreetQuery) Clone() *StreetQuery {
 		unique:     append([]string{}, sq.unique...),
 		predicates: append([]predicate.Street{}, sq.predicates...),
 		// clone intermediate query.
-		sql: sq.sql.Clone(),
+		sql:  sq.sql.Clone(),
+		path: sq.path,
 	}
 }
 
@@ -269,7 +286,12 @@ func (sq *StreetQuery) WithCity(opts ...func(*CityQuery)) *StreetQuery {
 func (sq *StreetQuery) GroupBy(field string, fields ...string) *StreetGroupBy {
 	group := &StreetGroupBy{config: sq.config}
 	group.fields = append([]string{field}, fields...)
-	group.sql = sq.sqlQuery()
+	group.path = func(ctx context.Context) (prev *sql.Selector, err error) {
+		if err := sq.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		return sq.sqlQuery(), nil
+	}
 	return group
 }
 
@@ -288,10 +310,27 @@ func (sq *StreetQuery) GroupBy(field string, fields ...string) *StreetGroupBy {
 func (sq *StreetQuery) Select(field string, fields ...string) *StreetSelect {
 	selector := &StreetSelect{config: sq.config}
 	selector.fields = append([]string{field}, fields...)
-	selector.sql = sq.sqlQuery()
+	selector.path = func(ctx context.Context) (prev *sql.Selector, err error) {
+		if err := sq.prepareQuery(ctx); err != nil {
+			return nil, err
+		}
+		return sq.sqlQuery(), nil
+	}
 	return selector
 }
 
+func (sq *StreetQuery) prepareQuery(ctx context.Context) error {
+	if sq.path != nil {
+		prev, err := sq.path(ctx)
+		if err != nil {
+			return err
+		}
+		sq.sql = prev
+	}
+	// Privacy and query checks go here.
+	return nil
+}
+
 func (sq *StreetQuery) sqlAll(ctx context.Context) ([]*Street, error) {
 	var (
 		nodes       = []*Street{}
@@ -438,8 +477,9 @@ type StreetGroupBy struct {
 	config
 	fields []string
 	fns    []Aggregate
-	// intermediate query.
-	sql *sql.Selector
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
 }
 
 // Aggregate adds the given aggregation functions to the group-by query.
@@ -450,6 +490,11 @@ func (sgb *StreetGroupBy) Aggregate(fns ...Aggregate) *StreetGroupBy {
 
 // Scan applies the group-by query and scan the result into the given value.
 func (sgb *StreetGroupBy) Scan(ctx context.Context, v interface{}) error {
+	query, err := sgb.path(ctx)
+	if err != nil {
+		return err
+	}
+	sgb.sql = query
 	return sgb.sqlScan(ctx, v)
 }
 
@@ -568,12 +613,18 @@ func (sgb *StreetGroupBy) sqlQuery() *sql.Selector {
 type StreetSelect struct {
 	config
 	fields []string
-	// intermediate queries.
-	sql *sql.Selector
+	// intermediate query (i.e. traversal path).
+	sql  *sql.Selector
+	path func(context.Context) (*sql.Selector, error)
 }
 
 // Scan applies the selector query and scan the result into the given value.
 func (ss *StreetSelect) Scan(ctx context.Context, v interface{}) error {
+	query, err := ss.path(ctx)
+	if err != nil {
+		return err
+	}
+	ss.sql = query
 	return ss.sqlScan(ctx, v)
 }