ref: Replace x/devtools/internal/envutil with x/lib/envvar
A while ago I wrote envutil in the devtools repo, to make it
easier to deal with environment variables, and to make it easy
for the v23 tool to keep track of the mutations it had made.
Later on I noticed that there was similar code in x/ref in a few
places.
This CL removes envutil, and adds a new package envvar that may
be used by all other packages. It behaves similarly to envutil,
and also to the code scattered around x/ref.
In a subsequent CL I'll add cmdline support for environment
variables using envvar.
MultiPart: 2/2
Change-Id: Idd5c06ab79badf678cd5ce7e87493c04ea16204a
diff --git a/lib/exec/consts.go b/lib/exec/consts.go
index f275d78..54bb5ae 100644
--- a/lib/exec/consts.go
+++ b/lib/exec/consts.go
@@ -12,3 +12,21 @@
// of environment variables; exposing the name of this variable is intended to
// support such situations.
const ExecVersionVariable = "V23_EXEC_VERSION"
+
+const (
+ version1 = "1.0.0"
+ readyStatus = "ready::"
+ failedStatus = "failed::"
+ initStatus = "init"
+
+ // eofChar is written onto the status pipe to signal end-of-file. It
+ // should be the last byte written onto the pipe, before closing it.
+ // This signals to the reader that no more input is coming. This is
+ // needed since we cannot use the closing of the write end of the pipe
+ // to send io.EOF to the reader: since there are two write ends (one in
+ // the parent and one in the child), closing any one of the two is not
+ // going to send io.EOF to the reader.
+ // Since the data coming from the child should be valid utf-8, we pick
+ // one of the invalid utf-8 bytes for this.
+ eofChar = 0xFF
+)
