buildkit/client/llb/async.go

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package llb
import (
"context"
"github.com/moby/buildkit/solver/pb"
"github.com/moby/buildkit/util/flightcontrol"
digest "github.com/opencontainers/go-digest"
"github.com/pkg/errors"
)
type asyncState struct {
f func(context.Context, State) (State, error)
prev State
target State
set bool
err error
g flightcontrol.Group
}
func (as *asyncState) Output() Output {
return as
}
func (as *asyncState) Vertex(ctx context.Context) Vertex {
err := as.Do(ctx)
if err != nil {
return &errVertex{err}
}
if as.set {
out := as.target.Output()
if out == nil {
return nil
}
return out.Vertex(ctx)
}
return nil
}
func (as *asyncState) ToInput(ctx context.Context, c *Constraints) (*pb.Input, error) {
err := as.Do(ctx)
if err != nil {
return nil, err
}
if as.set {
out := as.target.Output()
if out == nil {
return nil, nil
}
return out.ToInput(ctx, c)
}
return nil, nil
}
func (as *asyncState) Do(ctx context.Context) error {
_, err := as.g.Do(ctx, "", func(ctx context.Context) (interface{}, error) {
if as.set {
return as.target, as.err
}
res, err := as.f(ctx, as.prev)
if err != nil {
select {
case <-ctx.Done():
if errors.Is(err, ctx.Err()) {
return res, err
}
default:
}
}
as.target = res
as.err = err
as.set = true
return res, err
})
if err != nil {
return err
}
return as.err
}
type errVertex struct {
err error
}
func (v *errVertex) Validate(context.Context) error {
return v.err
}
func (v *errVertex) Marshal(context.Context, *Constraints) (digest.Digest, []byte, *pb.OpMetadata, []*SourceLocation, error) {
return "", nil, nil, nil, v.err
}
func (v *errVertex) Output() Output {
return nil
}
func (v *errVertex) Inputs() []Output {
return nil
}
var _ Vertex = &errVertex{}