1 files changed, 76 insertions, 0 deletions
diff --git a/vendor/github.com/cloudflare/tableflip/parent.go b/vendor/github.com/cloudflare/tableflip/parent.go
new file mode 100644
index 000000000..8b974d27c
--- /dev/null
+++ b/vendor/github.com/cloudflare/tableflip/parent.go
@@ -0,0 +1,76 @@
+package tableflip
+
+import (
+	"encoding/gob"
+	"io"
+	"io/ioutil"
+	"os"
+
+	"github.com/pkg/errors"
+)
+
+const (
+	sentinelEnvVar = "TABLEFLIP_HAS_PARENT_7DIU3"
+	notifyReady    = 42
+)
+
+type parent struct {
+	wr     *os.File
+	exited <-chan error
+}
+
+func newParent(env *env) (*parent, map[fileName]*file, error) {
+	if env.getenv(sentinelEnvVar) == "" {
+		return nil, make(map[fileName]*file), nil
+	}
+
+	wr := env.newFile(3, "write")
+	rd := env.newFile(4, "read")
+
+	var names [][]string
+	dec := gob.NewDecoder(rd)
+	if err := dec.Decode(&names); err != nil {
+		return nil, nil, errors.Wrap(err, "can't decode names from parent process")
+	}
+
+	files := make(map[fileName]*file)
+	for i, parts := range names {
+		var key fileName
+		copy(key[:], parts)
+
+		// Start at 5 to account for stdin, etc. and write
+		// and read pipes.
+		fd := 5 + i
+		env.closeOnExec(fd)
+		files[key] = &file{
+			env.newFile(uintptr(fd), key.String()),
+			uintptr(fd),
+		}
+	}
+
+	exited := make(chan error, 1)
+	go func() {
+		defer rd.Close()
+
+		n, err := io.Copy(ioutil.Discard, rd)
+		if n != 0 {
+			exited <- errors.New("unexpected data from parent process")
+		} else if err != nil {
+			exited <- errors.Wrap(err, "unexpected error while waiting for parent to exit")
+		}
+		close(exited)
+	}()
+
+	return &parent{
+		wr:     wr,
+		exited: exited,
+	}, files, nil
+}
+
+func (ps *parent) sendReady() error {
+	defer ps.wr.Close()
+	if _, err := ps.wr.Write([]byte{notifyReady}); err != nil {
+		return errors.Wrap(err, "can't notify parent process")
+	}
+	return nil
+}