Make inter-process communication with install-printerdriver script mo…

…re reliable

For adding package repositories and installing printer driver packages
out of them the install-printerdriver script is used. It provided data
to the caller from both stderr and stdout. As the data could come out
in an unexpected order a buffer could run full (especially with the
openprinting-gutenprint package which has a very long file list) and
block system-config-printer or make it crash (broken pipe).

Now all relevant data (progress and file list) is provided via stdout
and only stdout is read. This way the install-printerdriver script
works reliably.

install-printerdriver.py

@@ -9,8 +9,11 @@
 def progress(progress, type, user_data):
     if (type.value_name == "PK_PROGRESS_TYPE_PERCENTAGE" and
         progress.props.package != None):
-        sys.stderr.write ("%d\n" % progress.props.percentage)
-        sys.stderr.flush ()
+        sys.stdout.write ("P%d\n" % progress.props.percentage)
+        sys.stdout.flush ()
+    else:
+        sys.stdout.write ("P%d\n" % -10)
+        sys.stdout.flush ()
 
 set_debugging (True)
 
@@ -46,7 +49,7 @@ def progress(progress, type, user_data):
 debugprint("pk.resolve")
 try:
     res = pk.resolve(PackageKitGlib.FilterEnum.NONE, [package],
-                     None, lambda p, t, d: True, None)
+                     None, progress, None)
     repo_enable_needed = False
     debugprint("pk.resolve succeeded")
 except GLib.GError:
@@ -90,7 +93,7 @@ def progress(progress, type, user_data):
 debugprint("pk.resolve")
 try:
     res = pk.resolve(PackageKitGlib.FilterEnum.NONE, [package],
-                     None, lambda p, t, d: True, None)
+                     None, progress, None)
     debugprint("pk.resolve succeeded")
 except GLib.GError:
     debugprint("pk.resolve failed")
@@ -136,7 +139,7 @@ def progress(progress, type, user_data):
         debugprint("pk.install_packages errored")
         sys.exit(1)
 
-debugprint("done")
+debugprint("Package successfully installed")
 # If we reach this point, the requested package is on the system, either
 # because we have installed it now or because it was already there
 
@@ -150,3 +153,6 @@ def progress(progress, type, user_data):
 if files:
     for f in files[0].get_property('files'):
         print(f)
+
+# Tell the caller that we are done
+print("done")

newprinter.py

@@ -981,24 +981,29 @@ def installdriverpackage (self, driver, onlycheckpresence = False):
         try:
             self.p = subprocess.Popen (args, env=new_environ, close_fds=True,
                                        stdin=subprocess.DEVNULL,
-                                       stdout=subprocess.PIPE,
-                                       stderr=subprocess.PIPE)
+                                       stdout=subprocess.PIPE)
             # Keep the UI refreshed while we wait for
             # the drivers query to complete.
             (stdout, stderr) = (self.p.stdout, self.p.stderr)
             done = False
             while self.p.poll() == None:
-                line = stderr.readline ().strip()
+                line = stdout.readline ().strip()
                 if (len(line) > 0):
                     if line == "done":
                         done = True
                         break
-                    try:
-                        percentage = float(line)
-                        if percentage > 0:
-                            pbar.set_fraction(percentage/100)
-                    except:
-                        pass
+                    elif line.startswith(b"P"):
+                        try:
+                            percentage = float(line[1:])
+                            if percentage >= 0:
+                                pbar.set_fraction(percentage/100)
+                            else:
+                                pbar.set_pulse_step(-percentage/100)
+                                pbar.pulse()
+                        except:
+                            pass
+                    else:
+                        self.installed_driver_files.append(line.decode("utf-8"));
                 while Gtk.events_pending ():
                     Gtk.main_iteration ()
                 if not line:
@@ -1014,9 +1019,8 @@ def installdriverpackage (self, driver, onlycheckpresence = False):
             self._installdialog.destroy ()
             self._installdialog = None
 
-        if ret:
-            for line in stdout.readlines ():
-                self.installed_driver_files.append(line.decode("utf-8"));
+        if not ret:
+            self.installed_driver_files = [];
 
         return ret