canceling a command in a sequence will now stop the subsequent commands from being run

Conflicts:
	alot/commands/globals.py
	alot/ui.py

4 files changed, 58 insertions, 28 deletions

diff --git a/alot/commands/__init__.py b/alot/commands/__init__.py
index cadb6426..3e8235e3 100644
--- a/alot/commands/__init__.py
+++ b/alot/commands/__init__.py
@@ -28,6 +28,11 @@ class Command(object):
         pass
 
 
+class CommandCanceled(Exception):
+    """ Exception triggered when an interactive command has been canceled
+    """
+    pass
+
 COMMANDS = {
     'search': {},
     'envelope': {},
diff --git a/alot/commands/globals.py b/alot/commands/globals.py
index 21b14afc..40eebf2f 100644
--- a/alot/commands/globals.py
+++ b/alot/commands/globals.py
@@ -4,6 +4,7 @@
 import os
 import code
 from twisted.internet import threads
+from twisted.internet import defer
 import subprocess
 import email
 import urwid
@@ -17,6 +18,7 @@ from alot.commands import Command, registerCommand
 from alot.completion import CommandLineCompleter
 from alot.commands import CommandParseError
 from alot.commands import commandfactory
+from alot.commands import CommandCanceled
 from alot import buffers
 from alot.widgets.utils import DialogBox
 from alot import helper
@@ -123,6 +125,8 @@ class PromptCommand(Command):
             # save into prompt history
             ui.commandprompthistory.append(cmdline)
             ui.apply_commandline(cmdline)
+        else:
+            raise CommandCanceled()
 
 
 @registerCommand(MODE, 'refresh')
@@ -746,8 +750,8 @@ class ComposeCommand(Command):
                 fromaddress = yield ui.prompt('From', completer=cmpl,
                                               tab=1)
                 if fromaddress is None:
-                    ui.notify('canceled')
-                    return
+                    raise CommandCanceled()
+
                 self.envelope.add('From', fromaddress)
 
         # add signature
@@ -802,8 +806,8 @@ class ComposeCommand(Command):
             to = yield ui.prompt('To',
                                  completer=completer)
             if to is None:
-                ui.notify('canceled')
-                return
+                raise CommandCanceled()
+
             self.envelope.add('To', to.strip(' \t\n,'))
 
         if settings.get('ask_subject') and \
@@ -811,8 +815,8 @@ class ComposeCommand(Command):
             subject = yield ui.prompt('Subject')
             logging.debug('SUBJECT: "%s"' % subject)
             if subject is None:
-                ui.notify('canceled')
-                return
+                raise CommandCanceled()
+
             self.envelope.add('Subject', subject)
 
         if settings.get('compose_ask_tags'):
@@ -820,8 +824,8 @@ class ComposeCommand(Command):
             tagsstring = yield ui.prompt('Tags', completer=comp)
             tags = filter(lambda x: x, tagsstring.split(','))
             if tags is None:
-                ui.notify('canceled')
-                return
+                raise CommandCanceled()
+
             self.envelope.tags = tags
 
         if self.attach:
@@ -878,18 +882,27 @@ class CommandSequenceCommand(Command):
         Command.__init__(self, **kwargs)
         self.cmdline = cmdline.strip()
 
-    @inlineCallbacks
     def apply(self, ui):
+
+        def apply_command(ignored, cmdstring, cmd):
+            logging.debug('CMDSEQ: apply %s' % str(cmdstring))
+            # store cmdline for use with 'repeat' command
+            if cmd.repeatable:
+                ui.last_commandline = self.cmdline.lstrip()
+            return ui.apply_command(cmd, handle_error=False)
+
+        # we initialize a deferred which is already triggered 
+        # so that our callbacks will start to be called 
+        # immediately as possible
+        d = defer.succeed(None)
+
         # split commandline if necessary
         for cmdstring in split_commandline(self.cmdline):
-            logging.debug('CMDSEQ: apply %s' % str(cmdstring))
             # translate cmdstring into :class:`Command`
             try:
                 cmd = commandfactory(cmdstring, ui.mode)
-                # store cmdline for use with 'repeat' command
-                if cmd.repeatable:
-                    ui.last_commandline = self.cmdline.lstrip()
-            except CommandParseError as e:
+            except CommandParseError, e:
                 ui.notify(e.message, priority='error')
                 return
-            yield ui.apply_command(cmd)
+            d.addCallback(apply_command, cmdstring, cmd)
+        return d
diff --git a/alot/commands/thread.py b/alot/commands/thread.py
index d09008d2..3c03644e 100644
--- a/alot/commands/thread.py
+++ b/alot/commands/thread.py
@@ -17,6 +17,7 @@ from alot.commands.globals import ExternalCommand
 from alot.commands.globals import FlushCommand
 from alot.commands.globals import ComposeCommand
 from alot.commands.globals import MoveCommand
+from alot.commands.globals import CommandCanceled
 from alot.commands.envelope import SendCommand
 from alot import completion
 from alot.db.utils import decode_header
@@ -385,8 +386,8 @@ class BounceMailCommand(Command):
             completer = None
         to = yield ui.prompt('To', completer=completer)
         if to is None:
-            ui.notify('canceled')
-            return
+            raise CommandCanceled()
+
         mail['Resent-To'] = to.strip(' \t\n,')
 
         logging.debug("bouncing mail")
@@ -823,7 +824,7 @@ class SaveAttachmentCommand(Command):
                     ui.notify('not a directory: %s' % self.path,
                               priority='error')
             else:
-                ui.notify('canceled')
+                raise CommandCanceled()
         else:  # save focussed attachment
             focus = ui.get_deep_focus()
             if isinstance(focus, AttachmentWidget):
@@ -842,7 +843,7 @@ class SaveAttachmentCommand(Command):
                     except (IOError, OSError) as e:
                         ui.notify(str(e), priority='error')
                 else:
-                    ui.notify('canceled')
+                    raise CommandCanceled()
 
 
 class OpenAttachmentCommand(Command):
diff --git a/alot/ui.py b/alot/ui.py
index 971345ac..682c37e6 100644
--- a/alot/ui.py
+++ b/alot/ui.py
@@ -7,6 +7,8 @@ from twisted.internet import reactor, defer
 
 from settings import settings
 from buffers import BufferlistBuffer
+from commands import commandfactory
+from commands import CommandCanceled
 from alot.commands import CommandParseError
 from alot.commands.globals import CommandSequenceCommand
 from alot.helper import string_decode
@@ -563,7 +565,7 @@ class UI(object):
         footer_att = settings.get_theming_attribute('global', 'footer')
         return urwid.AttrMap(columns, footer_att)
 
-    def apply_command(self, cmd):
+    def apply_command(self, cmd, handle_error=True):
         """
         applies a command
 
@@ -572,6 +574,11 @@ class UI(object):
 
         :param cmd: an applicable command
         :type cmd: :class:`~alot.commands.Command`
+        :param handle_error: if True, the caller wants to rely on the default
+                             error handling mechanism to process the eventual
+                             errors raised while the command is applied.
+                             This is the default.
+        :type handle_error: bool
         """
         if cmd:
             # define (callback) function that invokes post-hook
@@ -581,15 +588,18 @@ class UI(object):
                     return defer.maybeDeferred(cmd.posthook, ui=self,
                                                dbm=self.dbman)
 
-            # define error handler for Failures/Exceptions
+            # define a generic error handler for Failures/Exceptions
             # raised in cmd.apply()
             def errorHandler(failure):
-                logging.error(failure.getTraceback())
-                errmsg = failure.getErrorMessage()
-                if errmsg:
-                    msg = "%s\n(check the log for details)"
-                    self.notify(
-                        msg % failure.getErrorMessage(), priority='error')
+                if failure.check(CommandCanceled):
+                    self.notify('canceled')
+                else:
+                    logging.error(failure.getTraceback())
+                    errmsg = failure.getErrorMessage()
+                    if errmsg:
+                        msg = "%s\n(check the log for details)"
+                        self.notify(
+                            msg % failure.getErrorMessage(), priority='error')
 
             # call cmd.apply
             def call_apply(ignored):
@@ -599,5 +609,6 @@ class UI(object):
             d = defer.maybeDeferred(prehook, ui=self, dbm=self.dbman)
             d.addCallback(call_apply)
             d.addCallback(call_posthook)
-            d.addErrback(errorHandler)
+            if handle_error:
+                d.addErrback(errorHandler)
             return d