[kupfer: 24/67] Use OperationError to give real feedback for launch error

[Ulrik Sverdrup <usverdrup src gnome org>]

commit 46dcee54005b08f18def2662b72c3b10d7adf9cf
Author: Ulrik Sverdrup <ulrik sverdrup gmail com>
Date:   Tue Mar 15 22:52:30 2011 +0100

    Use OperationError to give real feedback for launch error
    
    Use OperationError to show a notification on launch error (for example
    'Failed to execute child process "testme" (No such file or directory)'

 kupfer/desktop_launch.py |   12 ++++++++++--
 kupfer/launch.py         |   13 ++++++++++---
 kupfer/obj/objects.py    |   13 ++++++++-----
 3 files changed, 28 insertions(+), 10 deletions(-)
---
diff --git a/kupfer/desktop_launch.py b/kupfer/desktop_launch.py
index 5d4feed..6df1a5b 100644
--- a/kupfer/desktop_launch.py
+++ b/kupfer/desktop_launch.py
@@ -31,6 +31,9 @@ def error_log(*args):
 def exc_log():
 	pretty.print_exc(__name__)
 
+class SpawnError (Exception):
+	"Error starting application"
+
 class ResourceLookupError (Exception):
 	"Unable to find resource"
 
@@ -73,6 +76,8 @@ def read_desktop_info(desktop_file):
 		de = xdg.DesktopEntry.DesktopEntry(desktop_file)
 	except xdg.Exceptions.Error:
 		raise ResourceReadError
+	if not de.getExec():
+		raise ResourceReadError("Invalid data: empty Exec key")
 	return {
 		"Terminal": de.getTerminal(),
 		"StartupNotify": de.getStartupNotify(),
@@ -256,6 +261,8 @@ def launch_app_info(app_info, gfiles=[], in_terminal=None, timestamp=None,
 	@desktop_file: specify location of desktop file
 	@launch_cb: Called once per launched process,
 	            like ``spawn_app``
+
+	Will pass on exceptions from spawn_app
 	"""
 	desktop_file = desktop_file or _file_for_app_info(app_info)
 	desktop_info = _info_for_desktop_file(desktop_file)
@@ -338,7 +345,8 @@ def spawn_app(app_info, argv, filelist, workdir=None, startup_notify=True,
 	@launch_cb: Called if successful with
 	            (argv, pid, notify_id, filelist, timestamp)
 
-	return PID on success, else None
+	return pid if successful
+	raise SpawnError on error
 	"""
 	notify_id = None
 	if startup_notify:
@@ -369,7 +377,7 @@ def spawn_app(app_info, argv, filelist, workdir=None, startup_notify=True,
 		error_log("Error Launching ", argv, unicode(exc))
 		if notify_id:
 			gtk.gdk.notify_startup_complete_with_id(notify_id)
-		return None
+		raise SpawnError(unicode(exc))
 	if launch_cb:
 		launch_cb(argv, pid, notify_id, filelist, timestamp)
 	return pid
diff --git a/kupfer/launch.py b/kupfer/launch.py
index f2edfa2..bc2b9d1 100644
--- a/kupfer/launch.py
+++ b/kupfer/launch.py
@@ -17,6 +17,10 @@ except ImportError, e:
 	pretty.print_info(__name__, "Disabling window tracking:", e)
 	wnck = None
 
+class LaunchError (Exception):
+	"Error launching application"
+
+
 default_associations = {
 	"evince" : "Document Viewer",
 	"file-roller" : "File Roller",
@@ -51,6 +55,8 @@ def launch_application(app_info, files=(), uris=(), paths=(), track=True,
 	if @activate, activate rather than start a new version
 
 	@app_rec is either an GAppInfo or (GAppInfo, desktop_file_path) tuple
+
+	Raises LaunchError on failed program start.
 	"""
 	assert app_info
 
@@ -82,11 +88,12 @@ def launch_application(app_info, files=(), uris=(), paths=(), track=True,
 	else:
 		launch_callback = None
 
-	ret = desktop_launch.launch_app_info(app_info, files,
+	try:
+		desktop_launch.launch_app_info(app_info, files,
 			   timestamp=_current_event_time(), desktop_file=desktop_file,
 			   launch_cb=launch_callback)
-	if not ret:
-		pretty.print_info(__name__, "Error launching", app_info)
+	except desktop_launch.SpawnError as exc:
+		raise LaunchError(unicode(exc))
 	return True
 
 def application_is_running(app_id):
diff --git a/kupfer/obj/objects.py b/kupfer/obj/objects.py
index 29f53a1..2184a57 100644
--- a/kupfer/obj/objects.py
+++ b/kupfer/obj/objects.py
@@ -15,7 +15,8 @@ import gobject
 
 from kupfer import icons, launch, utils
 from kupfer import pretty
-from kupfer.obj.base import Leaf, Action, Source, InvalidDataError
+from kupfer.obj.base import Leaf, Action, Source
+from kupfer.obj.base import InvalidDataError, OperationError
 from kupfer.obj import fileactions
 from kupfer.interface import TextRepresentation
 from kupfer.kupferstring import tounicode
@@ -226,10 +227,12 @@ class AppLeaf (Leaf):
 		@paths: a seq of bytestring paths
 		@activate: activate instead of start new
 		"""
-		return launch.launch_application(self.object, files=files, paths=paths,
-		                                 activate=activate,
-		                                 desktop_file=self.init_path)
-
+		try:
+			return launch.launch_application(self.object, files=files,
+			                                 paths=paths, activate=activate,
+			                                 desktop_file=self.init_path)
+		except launch.LaunchError as exc:
+			raise OperationError(unicode(exc))
 
 	def get_id(self):
 		"""Return the unique ID for this app.