Process stderr from substituters while doing have/info queries

2 files changed, 8 insertions, 0 deletions

diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 9270806a77..1f817a8695 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -90,6 +90,12 @@ size_t BufferedSource::read(unsigned char * data, size_t len)
 }
 
 
+bool BufferedSource::hasData()
+{
+    return bufPosOut < bufPosIn;
+}
+
+
 size_t FdSource::readUnbuffered(unsigned char * data, size_t len)
 {
     ssize_t n;
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 42dd271176..e1c4514dbb 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -63,6 +63,8 @@ struct BufferedSource : Source
     
     /* Underlying read call, to be overriden. */
     virtual size_t readUnbuffered(unsigned char * data, size_t len) = 0;
+
+    bool hasData();
 };