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Remove error from mapper function signature.
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Errors (if any) in mapper functions should be surfaced using panic() instead.
People shouldn't be burdened with writing `func(*Row) (T, error)` over and over
if 99% of the time they are never going to return any error.
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@bokwoon95
bokwoon95 committed Nov 30, 2022
1 parent 8b9daa1 commit d31a2ba
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Showing 8 changed files with 75 additions and 95 deletions.
67 changes: 25 additions & 42 deletions fetch_exec.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ type Cursor[T any] struct {
ctx context.Context
row *Row
sqlRows *sql.Rows
rowmapper func(*Row) (T, error)
rowmapper func(*Row) T
stats QueryStats
logSettings LogSettings
logger SqLogger
Expand All @@ -28,16 +28,16 @@ type Cursor[T any] struct {
}

// FetchCursor returns a new cursor.
func FetchCursor[T any](db DB, q Query, rowmapper func(*Row) (T, error)) (*Cursor[T], error) {
func FetchCursor[T any](db DB, q Query, rowmapper func(*Row) T) (*Cursor[T], error) {
return fetchCursor(context.Background(), db, q, rowmapper, 1)
}

// FetchCursorContext is like FetchCursor but additionally requires a context.Context.
func FetchCursorContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) (T, error)) (*Cursor[T], error) {
func FetchCursorContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) T) (*Cursor[T], error) {
return fetchCursor(ctx, db, q, rowmapper, 1)
}

func fetchCursor[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) (T, error), skip int) (c *Cursor[T], err error) {
func fetchCursor[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) T, skip int) (c *Cursor[T], err error) {
if db == nil {
return nil, fmt.Errorf("db is nil")
}
Expand All @@ -52,11 +52,8 @@ func fetchCursor[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row
// Get fields and dest from rowmapper
dialect := q.GetDialect()
c.row = newRow(dialect)
defer recoverRowmapperPanic(&err)
_, err = c.rowmapper(c.row)
if err != nil {
return nil, err
}
defer recoverPanic(&err)
_ = c.rowmapper(c.row)
c.row.active = true
if len(c.row.fields) == 0 || len(c.row.dest) == 0 {
return nil, fmt.Errorf("rowmapper did not yield any fields")
Expand Down Expand Up @@ -196,8 +193,8 @@ func (c *Cursor[T]) Result() (result T, err error) {
}
}
c.row.index = 0
defer recoverRowmapperPanic(&err)
result, c.stats.Err = c.rowmapper(c.row)
defer recoverPanic(&err)
result = c.rowmapper(c.row)
if c.stats.Err != nil {
c.log()
return result, c.stats.Err
Expand Down Expand Up @@ -237,7 +234,7 @@ func (c *Cursor[T]) Close() error {

// FetchOne returns the first result from running the given Query on the given
// DB.
func FetchOne[T any](db DB, q Query, rowmapper func(*Row) (T, error)) (T, error) {
func FetchOne[T any](db DB, q Query, rowmapper func(*Row) T) (T, error) {
cursor, err := fetchCursor(context.Background(), db, q, rowmapper, 1)
if err != nil {
return *new(T), err
Expand All @@ -247,7 +244,7 @@ func FetchOne[T any](db DB, q Query, rowmapper func(*Row) (T, error)) (T, error)
}

// FetchOneContext is like FetchOne but additionally requires a context.Context.
func FetchOneContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) (T, error)) (T, error) {
func FetchOneContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) T) (T, error) {
cursor, err := fetchCursor(ctx, db, q, rowmapper, 1)
if err != nil {
return *new(T), err
Expand All @@ -257,7 +254,7 @@ func FetchOneContext[T any](ctx context.Context, db DB, q Query, rowmapper func(
}

// FetchAll returns all results from running the given Query on the given DB.
func FetchAll[T any](db DB, q Query, rowmapper func(*Row) (T, error)) ([]T, error) {
func FetchAll[T any](db DB, q Query, rowmapper func(*Row) T) ([]T, error) {
cursor, err := fetchCursor(context.Background(), db, q, rowmapper, 1)
if err != nil {
return nil, err
Expand All @@ -267,7 +264,7 @@ func FetchAll[T any](db DB, q Query, rowmapper func(*Row) (T, error)) ([]T, erro
}

// FetchAllContext is like FetchAll but additionally requires a context.Context.
func FetchAllContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) (T, error)) ([]T, error) {
func FetchAllContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) T) ([]T, error) {
cursor, err := fetchCursor(ctx, db, q, rowmapper, 1)
if err != nil {
return nil, err
Expand All @@ -283,11 +280,11 @@ type CompiledFetch[T any] struct {
query string
args []any
params map[string][]int
rowmapper func(*Row) (T, error)
rowmapper func(*Row) T
}

// NewCompiledFetch returns a new CompiledFetch.
func NewCompiledFetch[T any](dialect string, query string, args []any, params map[string][]int, rowmapper func(*Row) (T, error)) *CompiledFetch[T] {
func NewCompiledFetch[T any](dialect string, query string, args []any, params map[string][]int, rowmapper func(*Row) T) *CompiledFetch[T] {
return &CompiledFetch[T]{
dialect: dialect,
query: query,
Expand All @@ -298,12 +295,12 @@ func NewCompiledFetch[T any](dialect string, query string, args []any, params ma
}

// CompileFetch returns a new CompileFetch.
func CompileFetch[T any](q Query, rowmapper func(*Row) (T, error)) (*CompiledFetch[T], error) {
func CompileFetch[T any](q Query, rowmapper func(*Row) T) (*CompiledFetch[T], error) {
return CompileFetchContext(context.Background(), q, rowmapper)
}

// CompileFetchContext is like CompileFetch but accpets a context.Context.
func CompileFetchContext[T any](ctx context.Context, q Query, rowmapper func(*Row) (T, error)) (f *CompiledFetch[T], err error) {
func CompileFetchContext[T any](ctx context.Context, q Query, rowmapper func(*Row) T) (f *CompiledFetch[T], err error) {
if q == nil {
return nil, fmt.Errorf("query is nil")
}
Expand All @@ -314,11 +311,8 @@ func CompileFetchContext[T any](ctx context.Context, q Query, rowmapper func(*Ro
// Get fields from rowmapper
dialect := q.GetDialect()
row := newRow(dialect)
defer recoverRowmapperPanic(&err)
_, err = rowmapper(row)
if err != nil {
return nil, err
}
defer recoverPanic(&err)
_ = rowmapper(row)
if len(row.fields) == 0 {
return nil, fmt.Errorf("rowmapper did not yield any fields")
}
Expand Down Expand Up @@ -366,8 +360,8 @@ func (f *CompiledFetch[T]) fetchCursor(ctx context.Context, db DB, params Params

// Get fields and dest from rowmapper
c.row = newRow(f.dialect)
defer recoverRowmapperPanic(&err)
_, err = c.rowmapper(c.row)
defer recoverPanic(&err)
_ = c.rowmapper(c.row)
if err != nil {
return nil, err
}
Expand Down Expand Up @@ -456,7 +450,7 @@ func (f *CompiledFetch[T]) FetchAllContext(ctx context.Context, db DB, params Pa

// GetSQL returns a copy of the dialect, query, args, params and rowmapper that
// make up the CompiledFetch.
func (f *CompiledFetch[T]) GetSQL() (dialect string, query string, args []any, params map[string][]int, rowmapper func(*Row) (T, error)) {
func (f *CompiledFetch[T]) GetSQL() (dialect string, query string, args []any, params map[string][]int, rowmapper func(*Row) T) {
dialect = f.dialect
query = f.query
args = make([]any, len(f.args))
Expand Down Expand Up @@ -501,12 +495,12 @@ type PreparedFetch[T any] struct {
}

// PrepareFetch returns a new PreparedFetch.
func PrepareFetch[T any](db DB, q Query, rowmapper func(*Row) (T, error)) (*PreparedFetch[T], error) {
func PrepareFetch[T any](db DB, q Query, rowmapper func(*Row) T) (*PreparedFetch[T], error) {
return PrepareFetchContext(context.Background(), db, q, rowmapper)
}

// PrepareFetchContext is like PrepareFetch but additionally requires a context.Context.
func PrepareFetchContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) (T, error)) (*PreparedFetch[T], error) {
func PrepareFetchContext[T any](ctx context.Context, db DB, q Query, rowmapper func(*Row) T) (*PreparedFetch[T], error) {
compiledFetch, err := CompileFetchContext(ctx, q, rowmapper)
if err != nil {
return nil, err
Expand Down Expand Up @@ -539,8 +533,8 @@ func (f *PreparedFetch[T]) fetchCursor(ctx context.Context, params Params, skip

// Get fields and dest from rowmapper
c.row = newRow(f.compiled.dialect)
defer recoverRowmapperPanic(&err)
_, err = c.rowmapper(c.row)
defer recoverPanic(&err)
_ = c.rowmapper(c.row)
if err != nil {
return nil, err
}
Expand Down Expand Up @@ -913,17 +907,6 @@ func (e *PreparedExec) exec(ctx context.Context, params Params, skip int) (resul
return execResult(res, &stats)
}

func recoverRowmapperPanic(err *error) {
if r := recover(); r != nil {
switch r := r.(type) {
case error:
*err = r
default:
*err = fmt.Errorf("rowmapper panic: %v", r)
}
}
}

func getFieldNames(ctx context.Context, dialect string, fields []Field) []string {
buf := bufpool.Get().(*bytes.Buffer)
buf.Reset()
Expand Down
15 changes: 6 additions & 9 deletions fetch_exec_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,13 +26,13 @@ type Actor struct {
LastUpdate time.Time
}

func (actor Actor) RowMapper(a ACTOR) func(*Row) (Actor, error) {
return func(row *Row) (Actor, error) {
func (actor Actor) RowMapper(a ACTOR) func(*Row) Actor {
return func(row *Row) Actor {
actor.ActorID = row.IntField(a.ACTOR_ID)
actor.FirstName = row.StringField(a.FIRST_NAME)
actor.LastName = row.StringField(a.LAST_NAME)
actor.LastUpdate = row.TimeField(a.LAST_UPDATE)
return actor, nil
return actor
}
}

Expand Down Expand Up @@ -69,14 +69,13 @@ func TestFetchExec(t *testing.T) {
// Exec
res, err := Exec(Log(db), SQLite.
InsertInto(a).
ColumnValues(func(col *Column) error {
ColumnValues(func(col *Column) {
for _, actor := range __actors__ {
col.SetInt(a.ACTOR_ID, actor.ActorID)
col.SetString(a.FIRST_NAME, actor.FirstName)
col.SetString(a.LAST_NAME, actor.LastName)
col.SetTime(a.LAST_UPDATE, actor.LastUpdate)
}
return nil
}),
)
if err != nil {
Expand Down Expand Up @@ -121,12 +120,11 @@ func TestCompiledFetchExec(t *testing.T) {
// CompiledExec
insertActor, err := CompileExec(SQLite.
InsertInto(a).
ColumnValues(func(col *Column) error {
ColumnValues(func(col *Column) {
col.Set(a.ACTOR_ID, IntParam("actor_id", 0))
col.Set(a.FIRST_NAME, StringParam("first_name", ""))
col.Set(a.LAST_NAME, StringParam("last_name", ""))
col.Set(a.LAST_UPDATE, TimeParam("last_update", time.Time{}))
return nil
}),
)
if err != nil {
Expand Down Expand Up @@ -187,12 +185,11 @@ func TestPreparedFetchExec(t *testing.T) {
// PreparedExec
insertActor, err := PrepareExec(Log(db), SQLite.
InsertInto(a).
ColumnValues(func(col *Column) error {
ColumnValues(func(col *Column) {
col.Set(a.ACTOR_ID, IntParam("actor_id", 0))
col.Set(a.FIRST_NAME, StringParam("first_name", ""))
col.Set(a.LAST_NAME, StringParam("last_name", ""))
col.Set(a.LAST_UPDATE, TimeParam("last_update", time.Time{}))
return nil
}),
)
if err != nil {
Expand Down
18 changes: 9 additions & 9 deletions insert_query.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@ import (
// InsertQuery represents an SQL INSERT query.
type InsertQuery struct {
Dialect string
ColumnMapper func(*Column) error
ColumnMapper func(*Column)
// WITH
CTEs []CTE
// INSERT INTO
Expand All @@ -30,14 +30,14 @@ type InsertQuery struct {
var _ Query = (*InsertQuery)(nil)

// WriteSQL implements the SQLWriter interface.
func (q InsertQuery) WriteSQL(ctx context.Context, dialect string, buf *bytes.Buffer, args *[]any, params map[string][]int) error {
var err error
func (q InsertQuery) WriteSQL(ctx context.Context, dialect string, buf *bytes.Buffer, args *[]any, params map[string][]int) (err error) {
if q.ColumnMapper != nil {
col := &Column{
dialect: q.Dialect,
isUpdate: false,
}
err = q.ColumnMapper(col)
defer recoverPanic(&err)
q.ColumnMapper(col)
if err != nil {
return err
}
Expand Down Expand Up @@ -159,7 +159,7 @@ func (q InsertQuery) Values(values ...any) InsertQuery {
}

// ColumnValues sets the ColumnMapper field of the InsertQuery.
func (q InsertQuery) ColumnValues(colmapper func(*Column) error) InsertQuery {
func (q InsertQuery) ColumnValues(colmapper func(*Column)) InsertQuery {
q.ColumnMapper = colmapper
return q
}
Expand Down Expand Up @@ -317,7 +317,7 @@ func (q SQLiteInsertQuery) Values(values ...any) SQLiteInsertQuery {
}

// ColumnValues sets the ColumnMapper field of the SQLiteInsertQuery.
func (q SQLiteInsertQuery) ColumnValues(colmapper func(*Column) error) SQLiteInsertQuery {
func (q SQLiteInsertQuery) ColumnValues(colmapper func(*Column)) SQLiteInsertQuery {
q.ColumnMapper = colmapper
return q
}
Expand Down Expand Up @@ -418,7 +418,7 @@ func (q PostgresInsertQuery) Values(values ...any) PostgresInsertQuery {
}

// ColumnValues sets the ColumnMapper field of the PostgresInsertQuery.
func (q PostgresInsertQuery) ColumnValues(colmapper func(*Column) error) PostgresInsertQuery {
func (q PostgresInsertQuery) ColumnValues(colmapper func(*Column)) PostgresInsertQuery {
q.ColumnMapper = colmapper
return q
}
Expand Down Expand Up @@ -541,7 +541,7 @@ func (q MySQLInsertQuery) As(rowAlias string) MySQLInsertQuery {
}

// ColumnValues sets the ColumnMapper field of the MySQLInsertQuery.
func (q MySQLInsertQuery) ColumnValues(colmapper func(*Column) error) MySQLInsertQuery {
func (q MySQLInsertQuery) ColumnValues(colmapper func(*Column)) MySQLInsertQuery {
q.ColumnMapper = colmapper
return q
}
Expand Down Expand Up @@ -610,7 +610,7 @@ func (q SQLServerInsertQuery) Values(values ...any) SQLServerInsertQuery {
}

// ColumnValues sets the ColumnMapper field of the SQLServerInsertQuery.
func (q SQLServerInsertQuery) ColumnValues(colmapper func(*Column) error) SQLServerInsertQuery {
func (q SQLServerInsertQuery) ColumnValues(colmapper func(*Column)) SQLServerInsertQuery {
q.ColumnMapper = colmapper
return q
}
Expand Down
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