Move prototype 69-dagger-archon to top-level

Signed-off-by: Solomon Hykes <sh.github.6811@hykes.org>

dagger/state.go

@@ -0,0 +1,53 @@
+package dagger
+
+import (
+	"context"
+	"os"
+
+	"github.com/moby/buildkit/client/llb"
+	bkgw "github.com/moby/buildkit/frontend/gateway/client"
+)
+
+type State struct {
+	// Before last solve
+	input llb.State
+	// After last solve
+	output bkgw.Reference
+	// How to produce the output
+	s Solver
+}
+
+func NewState(s Solver) *State {
+	return &State{
+		input: llb.Scratch(),
+		s:     s,
+	}
+}
+
+func (s *State) ReadFile(ctx context.Context, filename string) ([]byte, error) {
+	if s.output == nil {
+		return nil, os.ErrNotExist
+	}
+	return s.output.ReadFile(ctx, bkgw.ReadRequest{Filename: filename})
+}
+
+func (s *State) Change(ctx context.Context, op interface{}) error {
+	input := s.input
+	switch OP := op.(type) {
+	case llb.State:
+		input = OP
+	case func(llb.State) llb.State:
+		input = OP(input)
+	}
+	output, err := s.s.Solve(ctx, input)
+	if err != nil {
+		return err
+	}
+	s.input = input
+	s.output = output
+	return nil
+}
+
+func (s *State) LLB() llb.State {
+	return s.input
+}