zip/internal/layout/types.go

// Package layout holds the types that [zip.Layouts] is proved against.
//
// The proof it exists for is byte equality: for a type the REFLECTIVE encoder
// can write, the generated codec must write the same bytes and read back the
// same value. That is what lets a fleet roll a generated codec out one pod at a
// time — the pod on the old path and the pod on the new one are speaking one
// wire, not two — and it is the property a second derivation of the layout would
// silently break.
//
// The fixtures cover every slot form the emitter has a branch for, plus the one
// the reflective encoder refuses outright: bytes_fixed[N], where there are no
// bytes to compare against because there are none at all.
package layout

// Count is a defined scalar, which needs a conversion on the way in and out.
type Count uint64

// Leaf is a nested value and a list element.
type Leaf struct {
	N uint32
	S string
}

// Sealed is a value with no slots: every field is unexported, so there is
// nothing to state and nothing crosses. time.Time and netip.AddrPort are this
// from the wire's side.
type Sealed struct {
	when  int64
	where string
}

// Trunk carries one field of every form the emitter writes.
type Trunk struct {
	B     bool
	I8    int8
	I16   int16
	I32   int32
	I64   int64
	U8    uint8
	U16   uint16
	U32   uint32
	U64   uint64
	F32   float32
	F64   float64
	C     Count
	Text  string
	Raw   []byte
	Leaf  Leaf
	PtrU  *uint64
	PtrS  *string
	PtrB  *bool
	PtrL  *Leaf
	Nums  []uint32
	Sigs  []int32
	Bigs  []float64
	Strs  []string
	Bufs  [][]byte
	Bits  []bool
	Kids  []Leaf
	Ptrs  []*Leaf
	Seal  Sealed
	Seals []Sealed
	PKids *[]Leaf
	PNums *[]uint32
	PtrI8 *int8
	PtrI6 *int16
	PtrI3 *int32
	PtrI4 *int64
	PtrU1 *uint8
	PtrU6 *uint16
	PtrU3 *uint32
	PtrF3 *float32
	PtrF6 *float64
	PtrC  *Count
	PtrR  *[]byte
}

// Ided is what the reflective encoder refuses: an id is [32]byte, and a fixed
// array has a layout the reflective codec deliberately does not carry.
type Ided struct {
	ID   [32]byte
	Name string
	IDs  [][32]byte
	Leaf Leaf
}

// Loose is Ided with no codec generated for it, which is what the reflective
// encoder is left holding when a type has not stated its wire.
type Loose struct {
	ID   [32]byte
	Name string
}