Add ipy_signals for better ctrl + C processing

IPython/Extensions/ipy_signals.py

@@ -0,0 +1,45 b''
+""" Advanced signal (e.g. ctrl+C) handling for IPython
+
+So far, this only ignores ctrl + C in IPython file a subprocess
+is executing, to get closer to how a "proper" shell behaves.
+
+Other signal processing may be implemented later on.
+
+If _ip.options.verbose is true, show exit status if nonzero
+
+"""
+
+import signal,os
+import IPython.ipapi
+import subprocess
+
+ip = IPython.ipapi.get()
+
+
+def new_ipsystem(cmd):
+    """ ctrl+c ignoring replacement for system() command in iplib.
+    
+    Ignore ctrl + c in IPython process during the command execution. 
+    The subprocess will still get the ctrl + c signal.
+    """
+    
+    p =  subprocess.Popen(cmd, shell = True)
+    
+    old_handler = signal.signal(signal.SIGINT, signal.SIG_IGN)
+    pid,status = os.waitpid(p.pid,0)
+    signal.signal(signal.SIGINT, old_handler)
+    if status and ip.options.verbose:
+        print "[exit status: %d]" % status
+    
+def init():
+    o = ip.options
+    try:
+        o.verbose
+    except AttributeError:
+        o.allow_new_attr (True )
+        o.verbose = 0
+        
+    ip.IP.system = new_ipsystem
+    
+init()
+    
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