grapher: integrate graph events from stdin with the stap process framework.

This was the original way to do graphing and had bitrotted some.

* grapher/StapParser.cxx (initIO): new catchHUP argument
  (ioCallback): Only disconnect signals, etc. on IN_HUP if catchHUP is
  true.
  (errIoCallback): Write error messages to stderr, not stdout.
* grapher/grapher.cxx (StapLauncher::launch): Don't catchHUP on our
  stap process children.
  (ProcWindow::refresh): Display something reasonable for the stap
  "process" that is feeding stdin.
  (main): Use StapParser::initIO to initialize parser reading from
  stdin.

1 files changed, 20 insertions, 11 deletions

diff --git a/grapher/StapParser.cxx b/grapher/StapParser.cxx
index a9a5109a..2513680b 100644
--- a/grapher/StapParser.cxx
+++ b/grapher/StapParser.cxx
@@ -86,9 +86,12 @@ vector<string> commaSplit(const boost::sub_range<Glib::ustring>& range)
     using namespace boost;
     if (ioCondition & Glib::IO_HUP)
       {
-        childDiedSignal().emit(getPid());
-        _ioConnection.disconnect();
-        _errIoConnection.disconnect();
+        if (_catchHUP)
+          {
+            childDiedSignal().emit(getPid());
+            _ioConnection.disconnect();
+            _errIoConnection.disconnect();
+          }
         return true;
       }
     if ((ioCondition & Glib::IO_IN) == 0)
@@ -261,22 +264,28 @@ vector<string> commaSplit(const boost::sub_range<Glib::ustring>& range)
         cerr << "StapParser: error reading from stderr!\n";
         return true;
       }
-    if (write(STDOUT_FILENO, buf, bytes_read) < 0)
+    if (write(STDERR_FILENO, buf, bytes_read) < 0)
       ;
     return true;
   }
 
-  void StapParser::initIo(int inFd, int errFd)
+  void StapParser::initIo(int inFd, int errFd, bool catchHUP)
   {
     _inFd = inFd;
     _errFd = errFd;
+    _catchHUP = catchHUP;
+    Glib::IOCondition inCond = Glib::IO_IN;
+    if (catchHUP)
+      inCond |= Glib::IO_HUP;
+    if (_errFd >= 0)
+      {    
+        _errIoConnection = Glib::signal_io()
+          .connect(sigc::mem_fun(*this, &StapParser::errIoCallback),
+                                  _errFd, Glib::IO_IN);
+      }
     _ioConnection = Glib::signal_io()
-      .connect(sigc::mem_fun(*this, &StapParser::errIoCallback),
-               _errFd,
-               Glib::IO_IN);
-    _errIoConnection = Glib::signal_io()
       .connect(sigc::mem_fun(*this, &StapParser::ioCallback),
-               _inFd,
-               Glib::IO_IN | Glib::IO_HUP);
+               _inFd, inCond);
+
   }
 }