UpsertFunc

lib/errs/error.go

@@ -8,26 +8,27 @@ import (
 )
 
 type Error struct {
-	msg        string
-	code       int64
+	Code       int64
+	Msg        string
+	StackTrace string
+
 	collection string
 	index      string
-	stackTrace string
 	err        error // Wrapped error
 }
 
 func NewErr(code int64, msg string) *Error {
 	return &Error{
-		msg:  msg,
-		code: code,
+		Code: code,
+		Msg:  msg,
 	}
 }
 
 func (e *Error) Error() string {
 	if e.collection != "" || e.index != "" {
-		return fmt.Sprintf(`[%d] (%s/%s) %s`, e.code, e.collection, e.index, e.msg)
+		return fmt.Sprintf(`[%d] (%s/%s) %s`, e.Code, e.collection, e.index, e.Msg)
 	} else {
-		return fmt.Sprintf("[%d] %s", e.code, e.msg)
+		return fmt.Sprintf("[%d] %s", e.Code, e.Msg)
 	}
 }
 
@@ -36,11 +37,15 @@ func (e *Error) Is(rhs error) bool {
 	if !ok {
 		return false
 	}
-	return e.code == e2.code
+	return e.Code == e2.Code
+}
+
+func (e *Error) Unwrap() error {
+	return e.err
 }
 
 func (e *Error) WithErr(err error) *Error {
-	if e2, ok := err.(*Error); ok && e2.code == e.code {
+	if e2, ok := err.(*Error); ok && e2.Code == e.Code {
 		return e2
 	}
 
@@ -49,18 +54,11 @@ func (e *Error) WithErr(err error) *Error {
 	return e2
 }
 
-func (e *Error) Unwrap() error {
-	if e.err != nil {
-		return e.err
-	}
-	return e
-}
-
 func (e *Error) WithMsg(msg string, args ...any) *Error {
 	err := *e
-	err.msg += ": " + fmt.Sprintf(msg, args...)
-	if len(err.stackTrace) == 0 {
-		err.stackTrace = string(debug.Stack())
+	err.Msg += ": " + fmt.Sprintf(msg, args...)
+	if len(err.StackTrace) == 0 {
+		err.StackTrace = string(debug.Stack())
 	}
 	return &err
 }
@@ -78,16 +76,16 @@ func (e *Error) WithIndex(s string) *Error {
 }
 
 func (e *Error) msgTruncacted() string {
-	if len(e.msg) > 255 {
-		return e.msg[:255]
+	if len(e.Msg) > 255 {
+		return e.Msg[:255]
 	}
-	return e.msg
+	return e.Msg
 }
 
 func (e *Error) Write(w io.Writer) error {
 	msg := e.msgTruncacted()
 
-	if err := binary.Write(w, binary.LittleEndian, e.code); err != nil {
+	if err := binary.Write(w, binary.LittleEndian, e.Code); err != nil {
 		return IO.WithErr(err)
 	}
 
@@ -103,7 +101,7 @@ func (e *Error) Read(r io.Reader) error {
 		size uint8
 	)
 
-	if err := binary.Read(r, binary.LittleEndian, &e.code); err != nil {
+	if err := binary.Read(r, binary.LittleEndian, &e.Code); err != nil {
 		return IO.WithErr(err)
 	}
 
@@ -116,6 +114,6 @@ func (e *Error) Read(r io.Reader) error {
 		return IO.WithErr(err)
 	}
 
-	e.msg = string(msgBuf)
+	e.Msg = string(msgBuf)
 	return nil
 }

lib/errs/fmt.go

@@ -10,12 +10,12 @@ func FmtDetails(err error) string {
 
 	var s string
 	if e.collection != "" || e.index != "" {
-		s = fmt.Sprintf(`[%d] (%s/%s) %s`, e.code, e.collection, e.index, e.msg)
+		s = fmt.Sprintf(`[%d] (%s/%s) %s`, e.Code, e.collection, e.index, e.Msg)
 	} else {
-		s = fmt.Sprintf("[%d] %s", e.code, e.msg)
+		s = fmt.Sprintf("[%d] %s", e.Code, e.Msg)
 	}
-	if len(e.stackTrace) != 0 {
-		s += "\n\nStack Trace:\n" + e.stackTrace + "\n"
+	if len(e.StackTrace) != 0 {
+		s += "\n\nStack Trace:\n" + e.StackTrace + "\n"
 	}
 
 	return s

mdb/collection.go

@@ -159,6 +159,15 @@ func (c *Collection[T]) Get(tx *Snapshot, id uint64) *T {
 	return c.ByID.Get(tx, item)
 }
 
+func (c *Collection[T]) Has(tx *Snapshot, id uint64) bool {
+	if tx == nil {
+		tx = c.db.Snapshot()
+	}
+	item := new(T)
+	c.setID(item, id)
+	return c.ByID.Has(tx, item)
+}
+
 func (c *Collection[T]) Insert(tx *Snapshot, userItem *T) error {
 	if tx == nil {
 		return c.db.Update(func(tx *Snapshot) error {
@@ -237,6 +246,27 @@ func (c *Collection[T]) update(tx *Snapshot, userItem *T) error {
 	return nil
 }
 
+func (c *Collection[T]) UpdateFunc(tx *Snapshot, id uint64, update func(item *T) error) error {
+	if tx == nil {
+		return c.db.Update(func(tx *Snapshot) error {
+			return c.updateFunc(tx, id, update)
+		})
+	}
+	return c.updateFunc(tx, id, update)
+}
+
+func (c *Collection[T]) updateFunc(tx *Snapshot, id uint64, update func(item *T) error) error {
+	item := c.Get(tx, id)
+	if item == nil {
+		return errs.NotFound
+	}
+	if err := update(item); err != nil {
+		return err
+	}
+	c.setID(item, id) // Don't allow the ID to change.
+	return c.update(tx, item)
+}
+
 func (c *Collection[T]) Upsert(tx *Snapshot, item *T) error {
 	if tx == nil {
 		return c.db.Update(func(tx *Snapshot) error {
@@ -257,6 +287,36 @@ func (c *Collection[T]) upsert(tx *Snapshot, item *T) error {
 	return err
 }
 
+func (c *Collection[T]) UpsertFunc(tx *Snapshot, id uint64, update func(item *T) error) error {
+	if tx == nil {
+		c.db.Update(func(tx *Snapshot) error {
+			return c.upsertFunc(tx, id, update)
+		})
+	}
+	return c.upsertFunc(tx, id, update)
+}
+
+func (c *Collection[T]) upsertFunc(tx *Snapshot, id uint64, update func(item *T) error) error {
+	insert := false
+
+	item := c.Get(tx, id)
+	if item == nil {
+		item = new(T)
+		insert = true
+	}
+
+	if err := update(item); err != nil {
+		return err
+	}
+
+	c.setID(item, id) // Don't allow the ID to change.
+
+	if insert {
+		return c.insert(tx, item)
+	}
+	return c.update(tx, item)
+}
+
 func (c *Collection[T]) Delete(tx *Snapshot, itemID uint64) error {
 	if tx == nil {
 		return c.db.Update(func(tx *Snapshot) error {