Put labelfile handling for commands in decorators

Instead of defining the label file opening, and possibly saving, logic
in each single command, put them in decorators so they can easily be
added to each command.

This lets us define a centralized point where loading and saving of
label files occur.

Also move the ‘dry-run’ flag to the write_labels decorator since that
is currently the only place that uses it. This again takes
responsibility away from each individual command.

I’ve opted to have the decorators add parameters to the ‘run’ method
since that seems fairly clear, and doesn’t start adding instance
variables out of nowhere.

Remove the option to create a label file when generating passphrases.

dispass/commands/add.py

@@ -20,10 +20,11 @@
 from dispass import algos
 from dispass.dispass import settings
 from dispass.cli import CLI
-from dispass.filehandler import Filehandler
 from dispass.interactive_editor import InteractiveEditor
+from dispass.commands.decorators import write_labels
 
 
+@write_labels
 class Command(CommandBase):
     '''Add a new label to the labelfile and generate passphrase.'''
     usagestr = (
@@ -40,11 +41,10 @@ class Command(CommandBase):
         ('generate', ('g', False,
                       'immediately generate passphrase after adding it')),
         ('help',    ('h', False, 'show this help information')),
-        ('dry-run', ('n', False, 'do not actually add label to labelfile')),
         ('silent',  ('s', False, 'do not print success message')),
     )
 
-    def run(self):
+    def run(self, lf):
         '''Parse labels and add them using `FileHandler.add`.
 
         When the -i flag is passed, add them using `InteractiveEditor.add`
@@ -53,15 +53,6 @@ def run(self):
         newlabels = []
         '''A list of labelnames that have been added.'''
 
-        if self.parentFlags['file']:
-            lf = Filehandler(settings, file_location=self.parentFlags['file'])
-        else:
-            lf = Filehandler(settings)
-
-        if not lf.file_found:
-            if not lf.promptForCreation(silent=self.flags['silent']):
-                return 1
-
         if self.flags['interactive']:
             intedit = InteractiveEditor(settings, lf, interactive=False)
             newlabels.append(intedit.add())
@@ -107,9 +98,6 @@ def run(self):
                         print("Label '{name}' already exists in labelfile"
                               .format(name=labelspec[0]))
 
-            if not self.flags['dry-run']:
-                lf.save()
-
         if self.flags['generate'] and newlabels:
             console = CLI(lf)
             console.verifyPassword = True

dispass/commands/decorators/__init__.py

@@ -0,0 +1,4 @@
+from .read_labels import read_labels
+from .write_labels import write_labels
+
+__all__ = [read_labels, write_labels]

dispass/commands/decorators/read_labels.py

@@ -0,0 +1,51 @@
+'''Decorator for commands that read labels'''
+
+# Copyright (c) 2012-2016  Tom Willemse <tom@ryuslash.org>
+# Copyright (c) 2011-2016  Benjamin Althues <benjamin@althu.es>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+from dispass.dispass import settings
+from dispass.filehandler import Filehandler
+
+
+def _run_with_labelfile(func, optional):
+    def run(inst, *args, **kwargs):
+        if inst.parentFlags['file']:
+            lf = Filehandler(settings, file_location=inst.parentFlags['file'])
+        else:
+            lf = Filehandler(settings)
+
+        if not lf.file_found and not optional:
+            print('error: could not load labelfile at "{loc}"'
+                  .format(loc=lf.file_location))
+            return 1
+
+        func(inst, lf, *args, **kwargs)
+
+    return run
+
+
+def read_labels(optional=False):
+    '''Decorate the `run` method of CLS.
+
+    An instance of dispass.labelfile.Filehandler is added to the front
+    of the argument list of the `run` method, after self. This file is
+    ready for reading.
+
+    '''
+    def func(cls):
+        cls.run = _run_with_labelfile(cls.run, optional)
+        return cls
+
+    return func

dispass/commands/decorators/write_labels.py

@@ -0,0 +1,57 @@
+'''Decorator for commands that write labels'''
+
+# Copyright (c) 2012-2016  Tom Willemse <tom@ryuslash.org>
+# Copyright (c) 2011-2016  Benjamin Althues <benjamin@althu.es>
+#
+# Permission to use, copy, modify, and distribute this software for any
+# purpose with or without fee is hereby granted, provided that the above
+# copyright notice and this permission notice appear in all copies.
+#
+# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+from dispass.dispass import settings
+from dispass.filehandler import Filehandler
+
+
+def _run_with_labelfile(func):
+    def run(inst, *args, **kwargs):
+        if inst.parentFlags['file']:
+            lf = Filehandler(settings, file_location=inst.parentFlags['file'])
+        else:
+            lf = Filehandler(settings)
+
+        if not lf.file_found:
+            if not lf.promptForCreation(silent=inst.flags['silent']):
+                return 1
+
+        func(inst, lf, *args, **kwargs)
+
+        if not inst.flags['dry-run']:
+            lf.save()
+
+    return run
+
+
+def write_labels(cls):
+    '''Decorate the `run` method of CLS.
+
+    An instance of dispass.labelfile.Filehandler is added to the front
+    of the argument list of the `run` method, after self. This file is
+    ready for writing. After the `run` method is finished, the label
+    file is automatically saved. A `dry-run` flag is also added to the
+    command indicating that the labelfile should not actually be
+    saved.
+
+    '''
+    cls.run = _run_with_labelfile(cls.run)
+    cls.optionList += (
+        ('dry-run', ('n', False, 'do not actually add label to labelfile')),
+    )
+
+    return cls

dispass/commands/disable.py

@@ -17,10 +17,10 @@
 
 from pycommand import CommandBase
 
-from dispass.dispass import settings
-from dispass.filehandler import Filehandler
+from dispass.commands.decorators import write_labels
 
 
+@write_labels
 class Command(CommandBase):
     '''Disable a label without throwing it away'''
 
@@ -34,26 +34,16 @@ class Command(CommandBase):
 
     optionList = (
         ('help',    ('h', False, 'show this help information')),
-        ('dry-run', ('n', False, 'do not actually update label in labelfile')),
         ('silent',  ('s', False, 'do not print success message')),
     )
 
-    def run(self):
+    def run(self, lf):
         '''Parse the arguments and disable using `Filehandler.disable`.'''
 
-        if self.parentFlags['file']:
-            lf = Filehandler(settings, file_location=self.parentFlags['file'])
-        else:
-            lf = Filehandler(settings)
-
         if not len(self.args) == 1 or self.flags['help']:
             print self.usage
             return
 
-        if not lf.file_found:
-            # File not found? No possible label to disable.
-            return 1
-
         labelname = self.args[0]
 
         if lf.disable(labelname):
@@ -63,6 +53,3 @@ def run(self):
             if not self.flags['silent']:
                 print("Label '{name}' could not be disabled"
                       .format(name=labelname))
-
-        if not self.flags['dry-run']:
-            lf.save()

dispass/commands/enable.py

@@ -17,10 +17,10 @@
 
 from pycommand import CommandBase
 
-from dispass.dispass import settings
-from dispass.filehandler import Filehandler
+from dispass.commands.decorators import write_labels
 
 
+@write_labels
 class Command(CommandBase):
     '''Enable a label'''
 
@@ -34,26 +34,16 @@ class Command(CommandBase):
 
     optionList = (
         ('help',    ('h', False, 'show this help information')),
-        ('dry-run', ('n', False, 'do not actually update label in labelfile')),
         ('silent',  ('s', False, 'do not print success message')),
     )
 
-    def run(self):
+    def run(self, lf):
         '''Parse the arguments and enable using `Filehandler.disable`.'''
 
-        if self.parentFlags['file']:
-            lf = Filehandler(settings, file_location=self.parentFlags['file'])
-        else:
-            lf = Filehandler(settings)
-
         if not len(self.args) == 1 or self.flags['help']:
             print self.usage
             return
 
-        if not lf.file_found:
-            # File not found? No possible label to enable.
-            return 1
-
         labelname = self.args[0]
 
         if lf.disable(labelname, False):
@@ -63,6 +53,3 @@ def run(self):
             if not self.flags['silent']:
                 print("Label '{name}' could not be enabled"
                       .format(name=labelname))
-
-        if not self.flags['dry-run']:
-            lf.save()

dispass/commands/generate.py

@@ -20,9 +20,10 @@
 from dispass.algos import algorithms
 from dispass.cli import CLI
 from dispass.dispass import settings
-from dispass.filehandler import Filehandler
+from dispass.commands.decorators import read_labels
 
 
+@read_labels(optional=True)
 class Command(CommandBase):
     '''Generate passphrases for one or more labels'''
 
@@ -44,7 +45,7 @@ class Command(CommandBase):
         ('silent',  ('', False, 'do not show a prompt when errors occur')),
     )
 
-    def run(self):
+    def run(self, lf):
         '''Parse the various arguments and output passphrases for each label
 
         Each positional argument is a label. For each label, it will try to
@@ -53,15 +54,6 @@ def run(self):
         settings object defined as `dispass.dispass.settings` will be used. The
         parameters can be overridden through the various optargs.
         '''
-        if self.parentFlags['file']:
-            lf = Filehandler(settings, file_location=self.parentFlags['file'])
-        else:
-            lf = Filehandler(settings)
-
-        if not lf.file_found:
-            if not lf.promptForCreation(silent=self.flags['silent']):
-                return 1
-
         if not self.args or self.flags['help']:
             print(self.usage)
             return 1

dispass/commands/gui.py

@@ -18,29 +18,24 @@
 from pycommand import CommandBase
 
 from dispass.dispass import settings
-from dispass.filehandler import Filehandler
+from dispass.commands.decorators import read_labels
 
 
+@read_labels(optional=True)
 class Command(CommandBase):
     '''Start the graphical version of DisPass'''
 
     usagestr = 'usage: dispass gui [-h]'
     description = 'Start the graphical version of DisPass.'
     optionList = (('help', ('h', False, 'show this help information')),)
 
-    def run(self):
+    def run(self, lf):
         '''Entry point and handler of command options and arguments'''
 
         if self.flags['help']:
             print(self.usage)
             return
 
-        if self.parentFlags['file']:
-            lf = Filehandler(settings,
-                             file_location=self.parentFlags['file'])
-        else:
-            lf = Filehandler(settings)
-
         try:
             from dispass.gui import GUI
             g = GUI(settings, lf)

dispass/commands/increment.py

@@ -19,8 +19,10 @@
 
 from dispass.dispass import settings
 from dispass.filehandler import Filehandler
+from dispass.commands.decorators import write_labels
 
 
+@write_labels
 class Command(CommandBase):
     '''Increment the sequence number of a label'''
 
@@ -35,26 +37,16 @@ class Command(CommandBase):
 
     optionList = (
         ('help',    ('h', False, 'show this help information')),
-        ('dry-run', ('n', False, 'do not actually update label in labelfile')),
         ('silent',  ('s', False, 'do not print success message')),
     )
 
-    def run(self):
+    def run(self, lf):
         '''Parse the arguments and increment using `FileHandler.increment`.'''
 
-        if self.parentFlags['file']:
-            lf = Filehandler(settings, file_location=self.parentFlags['file'])
-        else:
-            lf = Filehandler(settings)
-
         if not len(self.args) == 1 or self.flags['help']:
             print(self.usage)
             return
 
-        if not lf.file_found:
-            # File not found? No possible label to increment.
-            return 1
-
         labelname = self.args[0]
 
         if lf.increment(labelname):
@@ -64,6 +56,3 @@ def run(self):
             if not self.flags['silent']:
                 print("Label '{name}' could not be incremented"
                       .format(name=labelname))
-
-        if not self.flags['dry-run']:
-            lf.save()