Revert "libutil: drop Fs{Source,Sink}::good"

This reverts commit 1340807e30dba4b3972c31f02861bbaeaeb60e61.

Change-Id: I34d2a80eb3c3e9d79cb02b92cd1189da32d18cb6

2 files changed, 31 insertions, 3 deletions

diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 6450a9651..692144b75 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -52,7 +52,18 @@ FdSink::~FdSink()
 void FdSink::writeUnbuffered(std::string_view data)
 {
     written += data.size();
-    writeFull(fd, data);
+    try {
+        writeFull(fd, data);
+    } catch (SysError & e) {
+        _good = false;
+        throw;
+    }
+}
+
+
+bool FdSink::good()
+{
+    return _good;
 }
 
 
@@ -117,13 +128,19 @@ size_t FdSource::readUnbuffered(char * data, size_t len)
         checkInterrupt();
         n = ::read(fd, data, len);
     } while (n == -1 && errno == EINTR);
-    if (n == -1) { throw SysError("reading from file"); }
-    if (n == 0) { throw EndOfFile(std::string(*endOfFileError)); }
+    if (n == -1) { _good = false; throw SysError("reading from file"); }
+    if (n == 0) { _good = false; throw EndOfFile(std::string(*endOfFileError)); }
     read += n;
     return n;
 }
 
 
+bool FdSource::good()
+{
+    return _good;
+}
+
+
 size_t StringSource::read(char * data, size_t len)
 {
     if (pos == s.size()) throw EndOfFile("end of string reached");
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index e6290a652..d1c791823 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -18,6 +18,7 @@ struct Sink
 {
     virtual ~Sink() { }
     virtual void operator () (std::string_view data) = 0;
+    virtual bool good() { return true; }
 };
 
 /**
@@ -79,6 +80,8 @@ struct Source
      */
     virtual size_t read(char * data, size_t len) = 0;
 
+    virtual bool good() { return true; }
+
     void drainInto(Sink & sink);
 
     std::string drain();
@@ -133,6 +136,11 @@ struct FdSink : BufferedSink
     ~FdSink();
 
     void writeUnbuffered(std::string_view data) override;
+
+    bool good() override;
+
+private:
+    bool _good = true;
 };
 
 
@@ -157,8 +165,11 @@ struct FdSource : BufferedSource
         return *this;
     }
 
+    bool good() override;
 protected:
     size_t readUnbuffered(char * data, size_t len) override;
+private:
+    bool _good = true;
 };