unions, events and errors... oh my

nexgb/xgbgen/field.go

@@ -9,6 +9,7 @@ type Field interface {
 	Initialize(p *Protocol)
 	SrcName() string
 	XmlName() string
+	SrcType() string
 	Size() Size
 
 	Define(c *Context)
@@ -30,6 +31,10 @@ func (p *PadField) XmlName() string {
 	panic("illegal to take XML name of a pad field")
 }
 
+func (f *PadField) SrcType() string {
+	panic("it is illegal to call SrcType on a SwitchField field")
+}
+
 func (p *PadField) Size() Size {
 	return newFixedSize(p.Bytes)
 }
@@ -53,6 +58,10 @@ func (f *SingleField) XmlName() string {
 	return f.xmlName
 }
 
+func (f *SingleField) SrcType() string {
+	return f.Type.SrcName()
+}
+
 func (f *SingleField) Size() Size {
 	return f.Type.Size()
 }
@@ -72,9 +81,9 @@ func (f *ListField) XmlName() string {
 	return f.xmlName
 }
 
-// func (f *ListField) Size() Size { 
+func (f *ListField) SrcType() string {
-	// return newExpressionSize(f.LengthExpr).Multiply(f.Type.Size()) 
+	return fmt.Sprintf("[]%s", f.Type.SrcName())
-// } 
+}
 
 func (f *ListField) Size() Size {
 	simpleLen := &Function{
@@ -126,6 +135,10 @@ func (f *ExprField) XmlName() string {
 	return f.xmlName
 }
 
+func (f *ExprField) SrcType() string {
+	return f.Type.SrcName()
+}
+
 func (f *ExprField) Size() Size {
 	return f.Type.Size()
 }
@@ -150,6 +163,10 @@ func (f *ValueField) XmlName() string {
 	panic("it is illegal to call XmlName on a ValueField field")
 }
 
+func (f *ValueField) SrcType() string {
+	return f.MaskType.SrcName()
+}
+
 func (f *ValueField) Size() Size {
 	return f.MaskType.Size()
 }
@@ -174,6 +191,10 @@ func (f *SwitchField) XmlName() string {
 	panic("it is illegal to call XmlName on a SwitchField field")
 }
 
+func (f *SwitchField) SrcType() string {
+	panic("it is illegal to call SrcType on a SwitchField field")
+}
+
 // XXX: This is a bit tricky. The size has to be represented as a non-concrete
 // expression that finds *which* bitcase fields are included, and sums the
 // sizes of those fields.

nexgb/xgbgen/go_error.go

@@ -22,18 +22,36 @@ func (e *ErrorCopy) Define(c *Context) {
 	c.Putln("")
 	c.Putln("type %s %s", e.ErrType(), e.Old.(*Error).ErrType())
 	c.Putln("")
-	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.ErrType())
+
-	c.Putln("return (%s)(New%s(buf))", e.ErrType(), e.Old.SrcName())
+	// Read defines a function that transforms a byte slice into this
-	c.Putln("}")
+	// error struct.
-	c.Putln("")
+	e.Read(c)
+
+	// Write defines a function that transoforms this error struct into
+	// a byte slice.
+	e.Write(c)
+
+	// Makes sure that this error type is an Error interface.
 	c.Putln("func (err %s) ImplementsError() { }", e.ErrType())
 	c.Putln("")
-	c.Putln("func (err %s) Bytes() []byte {", e.ErrType())
+
-	c.Putln("return (%s)(err).Bytes()", e.Old.(*Error).ErrType())
+	// Let's the XGB know how to read this error.
-	c.Putln("}")
-	c.Putln("")
 	c.Putln("func init() {")
 	c.Putln("newErrorFuncs[%d] = New%s", e.Number, e.SrcName())
 	c.Putln("}")
 	c.Putln("")
 }
+
+func (e *ErrorCopy) Read(c *Context) {
+	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.ErrType())
+	c.Putln("return (%s)(New%s(buf))", e.ErrType(), e.Old.SrcName())
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *ErrorCopy) Write(c *Context) {
+	c.Putln("func (err %s) Bytes() []byte {", e.ErrType())
+	c.Putln("return (%s)(err).Bytes()", e.Old.(*Error).ErrType())
+	c.Putln("}")
+	c.Putln("")
+}

nexgb/xgbgen/go_event.go

@@ -3,14 +3,75 @@ package main
 // Event types
 func (e *Event) Define(c *Context) {
 	c.Putln("// Event definition %s (%d)", e.SrcName(), e.Number)
+	c.Putln("// Size: %s", e.Size())
+	c.Putln("type %s struct {", e.EvType())
+	c.Putln("Sequence uint16")
+	for _, field := range e.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Read defines a function that transforms a byte slice into this
+	// event struct.
+	e.Read(c)
+
+	// Write defines a function that transoforms this event struct into
+	// a byte slice.
+	e.Write(c)
+
+	// Makes sure that this event type is an Event interface.
+	c.Putln("func (v %s) ImplementsEvent() { }", e.EvType())
+	c.Putln("")
+
+	// Let's the XGB event loop read this event.
+	c.Putln("func init() {")
+	c.Putln("newEventFuncs[%d] = New%s", e.Number, e.SrcName())
+	c.Putln("}")
+	c.Putln("")
 }
 
-func (e *Event) Read(c *Context, prefix string) {
+func (e *Event) Read(c *Context) {
 	c.Putln("// Event read %s", e.SrcName())
+	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.EvType())
+	c.Putln("v := %s{}", e.EvType())
+	c.Putln("b := 1 // don't read event number")
+	c.Putln("")
+	for i, field := range e.Fields {
+		if i == 1 && !e.NoSequence {
+			c.Putln("v.Sequence = get16(buf[b:])")
+			c.Putln("b += 2")
+			c.Putln("")
+		}
+		field.Read(c)
+		c.Putln("")
+	}
+	c.Putln("return v")
+	c.Putln("}")
+	c.Putln("")
 }
 
-func (e *Event) Write(c *Context, prefix string) {
+func (e *Event) Write(c *Context) {
 	c.Putln("// Event write %s", e.SrcName())
+	c.Putln("func (v %s) Bytes() []byte {", e.EvType())
+	c.Putln("buf := make([]byte, %s)", e.Size())
+	c.Putln("b := 0")
+	c.Putln("")
+	c.Putln("// write event number")
+	c.Putln("buf[b] = %d", e.Number)
+	c.Putln("b += 1")
+	c.Putln("")
+	for i, field := range e.Fields {
+		if i == 1 && !e.NoSequence {
+			c.Putln("b += 2 // skip sequence number")
+			c.Putln("")
+		}
+		field.Write(c)
+		c.Putln("")
+	}
+	c.Putln("return buf")
+	c.Putln("}")
+	c.Putln("")
 }
 
 // EventCopy types
@@ -21,18 +82,36 @@ func (e *EventCopy) Define(c *Context) {
 	c.Putln("")
 	c.Putln("type %s %s", e.EvType(), e.Old.(*Event).EvType())
 	c.Putln("")
-	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.EvType())
+
-	c.Putln("return (%s)(New%s(buf))", e.EvType(), e.Old.SrcName())
+	// Read defines a function that transforms a byte slice into this
-	c.Putln("}")
+	// event struct.
-	c.Putln("")
+	e.Read(c)
-	c.Putln("func (ev %s) ImplementsEvent() { }", e.EvType())
+
-	c.Putln("")
+	// Write defines a function that transoforms this event struct into
-	c.Putln("func (ev %s) Bytes() []byte {", e.EvType())
+	// a byte slice.
-	c.Putln("return (%s)(ev).Bytes()", e.Old.(*Event).EvType())
+	e.Write(c)
-	c.Putln("}")
+
+	// Makes sure that this event type is an Event interface.
+	c.Putln("func (v %s) ImplementsEvent() { }", e.EvType())
 	c.Putln("")
+
+	// Let's the XGB event loop read this event.
 	c.Putln("func init() {")
 	c.Putln("newEventFuncs[%d] = New%s", e.Number, e.SrcName())
 	c.Putln("}")
 	c.Putln("")
 }
+
+func (e *EventCopy) Read(c *Context) {
+	c.Putln("func New%s(buf []byte) %s {", e.SrcName(), e.EvType())
+	c.Putln("return (%s)(New%s(buf))", e.EvType(), e.Old.SrcName())
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (e *EventCopy) Write(c *Context) {
+	c.Putln("func (v %s) Bytes() []byte {", e.EvType())
+	c.Putln("return (%s)(ev).Bytes()", e.Old.(*Event).EvType())
+	c.Putln("}")
+	c.Putln("")
+}

nexgb/xgbgen/go_list.go

@@ -12,8 +12,6 @@ func (f *ListField) Define(c *Context) {
 }
 
 func (f *ListField) Read(c *Context) {
-	c.Putln("")
-
 	switch t := f.Type.(type) {
 	case *Resource:
 		length := f.LengthExpr.Reduce("v.", "")
@@ -34,6 +32,10 @@ func (f *ListField) Read(c *Context) {
 			c.Putln("}")
 			c.Putln("b = pad(b)")
 		}
+	case *Union:
+		c.Putln("v.%s = make([]%s, %s)",
+			f.SrcName(), t.SrcName(), f.LengthExpr.Reduce("v.", ""))
+		c.Putln("b += Read%sList(buf[b:], v.%s)", t.SrcName(), f.SrcName())
 	case *Struct:
 		c.Putln("v.%s = make([]%s, %s)",
 			f.SrcName(), t.SrcName(), f.LengthExpr.Reduce("v.", ""))
@@ -45,8 +47,6 @@ func (f *ListField) Read(c *Context) {
 }
 
 func (f *ListField) Write(c *Context) {
-	c.Putln("")
-
 	switch t := f.Type.(type) {
 	case *Resource:
 		length := f.LengthExpr.Reduce("v.", "")
@@ -65,6 +65,8 @@ func (f *ListField) Write(c *Context) {
 			c.Putln("}")
 			c.Putln("b = pad(b)")
 		}
+	case *Union:
+		c.Putln("b += %sListBytes(buf[b:], v.%s)", t.SrcName(), f.SrcName())
 	case *Struct:
 		c.Putln("b += %sListBytes(buf[b:], v.%s)", t.SrcName(), f.SrcName())
 	default:

nexgb/xgbgen/go_single_field.go

@@ -25,6 +25,16 @@ func ReadSimpleSingleField(c *Context, name string, typ Type) {
 			c.Putln("%s = %s(get64(buf[b:]))", name, t.SrcName())
 		}
 	case *Base:
+		// If this is a bool, stop short and do something special.
+		if t.SrcName() == "bool" {
+			c.Putln("if buf[b] == 1 {")
+			c.Putln("%s = true", name)
+			c.Putln("} else {")
+			c.Putln("%s = false", name)
+			c.Putln("}")
+			break
+		}
+
 		var val string
 		switch t.Size().Eval() {
 		case 1:
@@ -44,7 +54,7 @@ func ReadSimpleSingleField(c *Context, name string, typ Type) {
 		}
 		c.Putln("%s = %s", name, val)
 	default:
-		log.Fatalf("Cannot read field '%s' as a simple field with %T type.",
+		log.Panicf("Cannot read field '%s' as a simple field with %T type.",
 			name, typ)
 	}
 
@@ -62,9 +72,11 @@ func (f *SingleField) Read(c *Context) {
 	case *Struct:
 		c.Putln("v.%s = %s{}", f.SrcName(), t.SrcName())
 		c.Putln("b += Read%s(buf[b:], &v.%s)", t.SrcName(), f.SrcName())
-		c.Putln("")
+	case *Union:
+		c.Putln("v.%s = %s{}", f.SrcName(), t.SrcName())
+		c.Putln("b += Read%s(buf[b:], &v.%s)", t.SrcName(), f.SrcName())
 	default:
-		log.Fatalf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
+		log.Panicf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)
 	}
 }
 
@@ -84,6 +96,16 @@ func WriteSimpleSingleField(c *Context, name string, typ Type) {
 			c.Putln("put64(buf[b:], uint64(%s))", name)
 		}
 	case *Base:
+		// If this is a bool, stop short and do something special.
+		if t.SrcName() == "bool" {
+			c.Putln("if %s {", name)
+			c.Putln("buf[b] = 1")
+			c.Putln("} else {")
+			c.Putln("buf[b] = 0")
+			c.Putln("}")
+			break
+		}
+
 		switch t.Size().Eval() {
 		case 1:
 			if t.SrcName() != "byte" {
@@ -126,11 +148,17 @@ func (f *SingleField) Write(c *Context) {
 		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
 	case *Base:
 		ReadSimpleSingleField(c, fmt.Sprintf("v.%s", f.SrcName()), t)
+	case *Union:
+		c.Putln("{")
+		c.Putln("unionBytes := v.%s.Bytes()", f.SrcName())
+		c.Putln("copy(buf[b:], unionBytes)")
+		c.Putln("b += pad(len(unionBytes))")
+		c.Putln("}")
 	case *Struct:
 		c.Putln("{")
 		c.Putln("structBytes := v.%s.Bytes()", f.SrcName())
 		c.Putln("copy(buf[b:], structBytes)")
-		c.Putln("b += len(structBytes)")
+		c.Putln("b += pad(len(structBytes))")
 		c.Putln("}")
 	default:
 		log.Fatalf("Cannot read field '%s' with %T type.", f.XmlName(), f.Type)

nexgb/xgbgen/go_struct.go

@@ -13,7 +13,7 @@ func (s *Struct) Define(c *Context) {
 	// Write function that reads bytes and produces this struct.
 	s.Read(c)
 
-	// Write function that reads a list of this structs.
+	// Write function that reads bytes and produces a list of this struct.
 	s.ReadList(c)
 
 	// Write function that writes bytes given this struct.
@@ -68,7 +68,7 @@ func (s *Struct) ReadList(c *Context) {
 func (s *Struct) Write(c *Context) {
 	c.Putln("// Struct write %s", s.SrcName())
 	c.Putln("func (v %s) Bytes() []byte {", s.SrcName())
-	c.Putln("buf := make([]byte, %s)", s.Size().Reduce("s.", ""))
+	c.Putln("buf := make([]byte, %s)", s.Size().Reduce("v.", ""))
 	c.Putln("b := 0")
 	c.Putln("")
 	for _, field := range s.Fields {
@@ -88,10 +88,11 @@ func (s *Struct) WriteList(c *Context) {
 	c.Putln("for _, item := range list {")
 	c.Putln("structBytes = item.Bytes()")
 	c.Putln("copy(buf[b:], len(structBytes))")
-	c.Putln("b += len(structBytes)")
+	c.Putln("b += pad(len(structBytes))")
 	c.Putln("}")
 	c.Putln("return b")
 	c.Putln("}")
+	c.Putln("")
 }
 
 func (s *Struct) WriteListSize(c *Context) {
@@ -101,7 +102,7 @@ func (s *Struct) WriteListSize(c *Context) {
 	c.Putln("for _, item := range list {")
 	c.Putln("size += %s", s.Size().Reduce("item.", ""))
 	c.Putln("}")
-	c.Putln("return pad(size)")
+	c.Putln("return size")
 	c.Putln("}")
 	c.Putln("")
 }

nexgb/xgbgen/go_union.go

@@ -3,13 +3,143 @@ package main
 // Union types
 func (u *Union) Define(c *Context) {
 	c.Putln("// Union definition %s", u.SrcName())
+	c.Putln("// Note that to *create* a Union, you should *never* create")
+	c.Putln("// this struct directly (unless you know what you're doing).")
+	c.Putln("// Instead use one of the following constructors for '%s':",
+		u.SrcName())
+	for _, field := range u.Fields {
+		c.Putln("//     New%s%s(%s %s) %s", u.SrcName(), field.SrcName(),
+			field.SrcName(), field.SrcType(), u.SrcName())
+	}
+
+	c.Putln("type %s struct {", u.SrcName())
+	for _, field := range u.Fields {
+		field.Define(c)
+	}
+	c.Putln("}")
+	c.Putln("")
+
+	// Write functions for each field that create instances of this
+	// union using the corresponding field.
+	u.New(c)
+
+	// Write function that reads bytes and produces this union.
+	u.Read(c)
+
+	// Write function that reads bytes and produces a list of this union.
+	u.ReadList(c)
+
+	// Write function that writes bytes given this union.
+	u.Write(c)
+
+	// Write function that writes a list of this union.
+	u.WriteList(c)
+
+	// Write function that computes the size of a list of these unions.
+	u.WriteListSize(c)
 }
 
-func (u *Union) Read(c *Context, prefix string) {
+func (u *Union) New(c *Context) {
+	for _, field := range u.Fields {
+		c.Putln("// Union constructor for %s for field %s.",
+			u.SrcName(), field.SrcName())
+		c.Putln("func New%s%s(%s %s) %s {",
+			u.SrcName(), field.SrcName(), field.SrcName(),
+			field.SrcType(), u.SrcName())
+		c.Putln("var b int")
+		c.Putln("buf := make([]byte, %s)", u.Size())
+		c.Putln("")
+		field.Write(c)
+		c.Putln("")
+		c.Putln("// Create the Union type")
+		c.Putln("v := %s{}", u.SrcName())
+		c.Putln("")
+		c.Putln("// Now copy buf into all fields")
+		c.Putln("")
+		for _, field2 := range u.Fields {
+			c.Putln("b = 0 // always read the same bytes")
+			field2.Read(c)
+			c.Putln("")
+		}
+		c.Putln("return v")
+		c.Putln("}")
+		c.Putln("")
+	}
+}
+
+func (u *Union) Read(c *Context) {
 	c.Putln("// Union read %s", u.SrcName())
+	c.Putln("func Read%s(buf []byte, v *%s) int {", u.SrcName(), u.SrcName())
+	c.Putln("var b int")
+	c.Putln("")
+	for _, field := range u.Fields {
+		c.Putln("b = 0 // re-read the same bytes")
+		field.Read(c)
+		c.Putln("")
+	}
+	c.Putln("return %s", u.Size())
+	c.Putln("}")
+	c.Putln("")
 }
 
-func (u *Union) Write(c *Context, prefix string) {
+func (u *Union) ReadList(c *Context) {
+	c.Putln("// Union list read %s", u.SrcName())
+	c.Putln("func Read%sList(buf []byte, dest []%s) int {",
+		u.SrcName(), u.SrcName())
+	c.Putln("b := 0")
+	c.Putln("for i := 0; i < len(dest); i++ {")
+	c.Putln("dest[i] = %s{}", u.SrcName())
+	c.Putln("b += Read%s(buf[b:], &dest[i])", u.SrcName())
+	c.Putln("}")
+	c.Putln("return pad(b)")
+	c.Putln("}")
+	c.Putln("")
+}
+
+// This is a bit tricky since writing from a Union implies that only
+// the data inside ONE of the elements is actually written.
+// However, we only currently support unions where every field has the
+// *same* *fixed* size. Thus, we make sure to always read bytes into
+// every field which allows us to simply pick the first field and write it.
+func (u *Union) Write(c *Context) {
 	c.Putln("// Union write %s", u.SrcName())
+	c.Putln("// Each field in a union must contain the same data.")
+	c.Putln("// So simply pick the first field and write that to the wire.")
+	c.Putln("func (v %s) Bytes() []byte {", u.SrcName())
+	c.Putln("buf := make([]byte, %s)", u.Size().Reduce("v.", ""))
+	c.Putln("b := 0")
+	c.Putln("")
+	u.Fields[0].Write(c)
+	c.Putln("return buf")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (u *Union) WriteList(c *Context) {
+	c.Putln("// Union list write %s", u.SrcName())
+	c.Putln("func %sListBytes(buf []byte, list []%s) int {",
+		u.SrcName(), u.SrcName())
+	c.Putln("b := 0")
+	c.Putln("var unionBytes []byte")
+	c.Putln("for _, item := range list {")
+	c.Putln("unionBytes = item.Bytes()")
+	c.Putln("copy(buf[b:], len(unionBytes))")
+	c.Putln("b += pad(len(unionBytes))")
+	c.Putln("}")
+	c.Putln("return b")
+	c.Putln("}")
+	c.Putln("")
+}
+
+func (u *Union) WriteListSize(c *Context) {
+	c.Putln("// Union list size %s", u.SrcName())
+	c.Putln("func %sListSize(list []%s) int {", u.SrcName(), u.SrcName())
+	c.Putln("size := 0")
+	c.Putln("for _, item := range list {")
+	c.Putln("size += %s", u.Size().Reduce("item.", ""))
+	c.Putln("}")
+	c.Putln("return size")
+	c.Putln("}")
+	c.Putln("")
 }
 

nexgb/xgbgen/type.go

@@ -191,7 +191,7 @@ func (e *Event) XmlName() string {
 }
 
 func (e *Event) Size() Size {
-	panic("Cannot take size of Event type.")
+	return newExpressionSize(&Value{v: 32})
 }
 
 func (e *Event) Initialize(p *Protocol) {
@@ -358,7 +358,7 @@ func (u *Union) Size() Size {
 }
 
 func (u *Union) Initialize(p *Protocol) {
-	u.srcName = TypeSrcName(p, u)
+	u.srcName = fmt.Sprintf("%sUnion", TypeSrcName(p, u))
 	for _, field := range u.Fields {
 		field.Initialize(p)
 	}