properly open and close processes

diff --git a/dsl.py b/dsl.py
index 890ea70e8cdc5b24520ea3cf30fe1b1b0fa56f06..d13d0a0f8dc058c008fe2e12dbc7393624cb242b 100755 (executable)
--- a/dsl.py
+++ b/dsl.py
@@ -78,13 +78,24 @@ def loadConfigFile(file):
        # add some convencience get functions
        return result
 
+# helper function: execute a process, return output as iterator, throw exception if there was an error
+# you *must* iterate to the end if you use this!
+def processOutputGen(*args):
+       p = subprocess.Popen(args, stdout=subprocess.PIPE)
+       for line in p.stdout:
+               yield line
+       p.wait() # wait for process to exit (it closed stdout, so it can't block anymore)
+       if p.returncode != 0:
+               raise Exception("Error executing "+str(args))
+def processOutputIt(*args):
+       return list(processOutputGen(*args)) # list() iterates over the generator
+
 # Run xrandr and return a dict of output names mapped to lists of available resolutions, each being a (width, height) pair.
 # An empty list indicates that the connector is disabled.
 def getXrandrInformation():
-       p = subprocess.Popen(["xrandr", "-q"], stdout=subprocess.PIPE)
        connectors = {} # map of connector names to a list of resolutions
        connector = None # current connector
-       for line in p.stdout:
+       for line in processOutputGen("xrandr", "-q"):
                # screen?
                m = re.search(r'^Screen [0-9]+: ', line)
                if m is not None: # ignore this line
@@ -107,10 +118,6 @@ def getXrandrInformation():
                # not fatal as my xrandr shows strange stuff when a display is enabled, but not connected
                #raise Exception("Unknown line in xrandr output:\n"+line)
                print "Warning: Unknown xrandr line %s" % line
-       # be sure to always proprly finish up with the xrandr
-       p.communicate()
-       # if everything succeededso far, check return code
-       if p.returncode != 0: raise Exception("Querying xrandr for data failed.")
        return connectors
 
 # convert a (width, height) pair into a string accepted by xrandr as argument for --mode

diff --git a/gui.py b/gui.py
index b3929cbed6835543ed23add3663b461d6cc2bc9b..6dabe0f048df2f0e47bc8dfa363a785bcc3266f2 100644 (file)
--- a/gui.py
+++ b/gui.py
@@ -39,7 +39,12 @@ def qtAvailable():
                return False
 
 def zenityAvailable():
-       return True # FIXME
+       try:
+               from dsl import processOutputIt
+               processOutputIt("zenity", "--version")
+               return True
+       except Exception:
+               return False
 
 # actual frontends
 if qtAvailable():

diff --git a/zenity_dialogue.py b/zenity_dialogue.py
index 69365e8325d8c8882f06450ca3f28ec5e0f1b6ee..60d7827f72527e863e0edeb42526a60bc7745b89 100644 (file)
--- a/zenity_dialogue.py
+++ b/zenity_dialogue.py
@@ -15,14 +15,13 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 
-import subprocess
-from dsl import RelativeScreenPosition, ScreenSetup, res2user
+from dsl import RelativeScreenPosition, ScreenSetup, res2user, processOutputIt
 
 def userChoose (title, choices, returns, fallback):
        assert len(choices) == len(returns)
-       p = subprocess.Popen(["zenity", "--list", "--text="+title, "--column="]+choices, stdout=subprocess.PIPE)
+       args = ["zenity", "--list", "--text="+title, "--column="]+choices
        switch = dict (zip (choices,returns))
-       for line in p.stdout: # FIXME use p.communicate()[0] instead to get entire stdout and ensure the process terminates. also check p.returncode.
+       for line in processOutputIt(*args):
                return switch.get(line.strip(), fallback)
        return fallback