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# -*- coding: utf-8 -*-
#
# File: portato/plugin.py
# This file is part of the Portato-Project, a graphical portage-frontend.
#
# Copyright (C) 2006-2009 René 'Necoro' Neumann
# This is free software. You may redistribute copies of it under the terms of
# the GNU General Public License version 2.
# There is NO WARRANTY, to the extent permitted by law.
#
# Written by René 'Necoro' Neumann <necoro@necoro.net>
"""
A module managing the plugins for Portato.
"""
from __future__ import absolute_import
__docformat__ = "restructuredtext"
import os
import os.path as osp
import traceback
from collections import defaultdict
from functools import wraps
from .helper import debug, warning, info, error
from .constants import PLUGIN_DIR
from .backend import system
from . import plugins as plugin_module
class PluginLoadException (Exception):
"""
Exception signaling a failed plugin loading.
"""
pass
class Call (object):
"""
This class represents an object, which is attached to a specified hook.
:IVariables:
plugin : `Plugin`
The plugin where this call belongs to.
hook : string
The name of the corresponding hook.
call
The function to call.
type : string
This is either ``before``, ``after`` or ``override`` and defines the type of the call:
before
access before the original function
override
access *instead of* the original function. **USE THIS ONLY IF YOU KNOW WHAT YOU ARE DOING**
after
access after the original function has been called
Default: ``before``
dep : string
This defines a plugin which should be executed after/before this one.
``"*"`` means all and ``"-*"`` means none.
"""
__slots__ = ("plugin", "hook", "call", "type", "dep")
def __init__ (self, plugin, hook, call, type = "before", dep = None):
self.plugin = plugin
self.hook = hook
self.call = call
self.type = type
self.dep = dep
class Hook (object):
"""
Representing a hook with all the `Call` s for the different types.
"""
__slots__ = ("before", "override", "after")
def __init__ (self):
self.before = []
self.override = None
self.after = []
class WidgetSlot (object):
"""
A slot, where plugins can add widgets.
:IVariables:
widget : gobject.GObjectMeta
The widget class, which can be used in this slot.
name : string
The slot's name.
init : function
Function to call, iff there is at least one widget for that slot.
add : function(`Widget`)
Function to call, if a widget is added.
max : int
The maximum number of widgets which can be registered. -1 means unlimited.
"""
slots = {}
def __init__ (self, widget, name, add = None, init = None, max = -1):
self.widget = widget
self.name = name
self.max = max
# we might be subclassed
# in this case do not overwrite
if not hasattr(self, "init"):
self.init = init
if not hasattr(self, "add"):
self.add = add
self._inited = False
debug("Registering new WidgetSlot '%s'.", name)
WidgetSlot.slots[name] = self
def add_widget (self, w):
if not self._inited:
if self.init is not None:
self.init()
self._inited = True
if self.add is not None:
self.add(w)
class Widget (object):
"""
Fills a WidgetSlot.
:IVariables:
slot : string
The name of the slot to fill.
widget : gtk.Widget
The widget which is added.
"""
__slots__ = ("slot", "widget")
def __init__ (self, slot, widget):
self.slot = slot
self.widget = widget
class Plugin (object):
"""
This is the main plugin object. It is used where ever a plugin is wanted, and it is the one, which needs to be subclassed by plugin authors.
:CVariables:
STAT_DISABLED : status
Status: Disabled.
STAT_TEMP_ENABLED : status
Status: Enabled for this session only.
STAT_ENABLED : status
Status: Enabled.
STAT_TEMP_DISABLED : status
Status: Disabled for this session only.
STAT_HARD_DISABLED : status
Status: Forced disabled by program (i.e. because of errors in the plugin).
"""
(STAT_DISABLED, STAT_TEMP_ENABLED, STAT_ENABLED, STAT_TEMP_DISABLED) = range(4)
STAT_HARD_DISABLED = -1
def __init__ (self, disable = False):
"""
:param disable: Forcefully disable the plugin
:type disable: bool
"""
self.__calls = [] #: List of `Call`
self._unresolved_deps = False #: Does this plugin has unresolved dependencies?
self.status = self.STAT_ENABLED #: The status of this plugin
if disable:
self.status = self.STAT_HARD_DISABLED
# debug test
if hasattr(self, "widget_init") and not isinstance(self, WidgetPlugin):
debug("Plugin '%s' has an init_widget() function but is not a WidgetPlugin. Are you sure, this is correct?", self.name)
def _init (self):
"""
Method called from outside to init the extension parts of this plugin.
If the current status is `STAT_HARD_DISABLED` or there are unresolved dependencies, the init process is not started.
"""
for d in self.deps:
if not system.find_packages(d, pkgSet=system.SET_INSTALLED, with_version = False):
self._unresolved_deps = True
break
if self.status != self.STAT_HARD_DISABLED and not self._unresolved_deps:
self.init()
def init (self):
"""
This method is called by `_init` and should be overriden by the plugin author.
:precond: No unresolved deps and the status is not `STAT_HARD_DISABLED`.
"""
pass
@property
def author (self):
"""
Returns the plugin's author.
The author is given by the ``__author__`` variable.
:rtype: string
"""
return getattr(self, "__author__", "")
@property
def description (self):
"""
Returns the description of this plugin.
It is given by either a ``__description__`` variable or by the normal class docstring.
:rtype: string
"""
if hasattr(self, "__description__"):
return self.__description__
else:
doc = getattr(self, "__doc__", "")
if not doc or doc == Plugin.__doc__:
return ""
else:
return doc
@property
def name (self):
"""
The name of the plugin. If no ``__name__`` variable is given, the class name is taken.
:rtype: string
"""
return getattr(self, "__name__", self.__class__.__name__)
@property
def calls (self):
"""
Returns an iterator over the registered calls for this plugin.
:rtype: iter<`Call`>
"""
return iter(self.__calls)
@property
def deps (self):
"""
Returns an iterator of the dependencies or ``[]`` if there are none.
The dependencies are given in the ``__dependency__`` variable.
:rtype: [] or iter<string>
"""
if hasattr(self, "__dependency__"):
return iter(self.__dependency__)
else:
return []
@property
def enabled (self):
"""
Returns ``True`` if the plugin is enabled.
:rtype: boolean
:see: `status`
"""
return (self.status in (self.STAT_ENABLED, self.STAT_TEMP_ENABLED))
def add_call (self, hook, callable, type = "before", dep = None):
"""
Adds a new call for this plugin.
:see: `Call`
"""
self.__calls.append(Call(self, hook, callable, type, dep))
class WidgetPlugin (Plugin):
def __init__ (self, *args, **kwargs):
Plugin.__init__(self, *args, **kwargs)
self.__widgets = [] #: List of `Widget`
def _widget_init (self, window):
self.window = window
if self.status == self.STAT_ENABLED and not self._unresolved_deps:
self.widget_init()
def widget_init (self):
debug("%s: No widgets to initialize. Wrong class used for plugin?", self.name)
def add_widget (self, slot, widget):
"""
Adds a new widget for this plugin.
:see: `Widget`
"""
if not slot in WidgetSlot.slots:
raise PluginLoadException, "Could not find specified widget slot: %s" % slot
self.__widgets.append(Widget(slot, widget))
def create_widget (self, slot, args, **kwargs):
"""
Creates a new widget for the plugin.
:Parameters:
slot : string
The slot to create a widget for.
args : list of objects
The arguments to pass to the widget constructor.
kwargs : dict
Additional named parameters are for callback functions.
"""
try:
widget = WidgetSlot.slots[slot].widget
except KeyError:
raise PluginLoadException, "Could not find specified widget slot: %s" % slot
if not hasattr(args, "__iter__"):
w = widget(args)
else:
w = widget(*args)
for k,v in kwargs.iteritems():
w.connect(k, v)
self.add_widget(slot, w)
@property
def widgets (self):
"""
Returns an iterator over the widgets for this plugin.
:rtype: iter<`Widget`>
"""
return iter(self.__widgets)
class PluginQueue (object):
"""
Class managing and loading the plugins.
:IVariables:
plugins : `Plugin` []
The list of managed plugins.
hooks : string -> `Hook`
For each hook name map to a `Hook` object holding the corresponding `Call` objects.
"""
def __init__ (self):
"""
Constructor.
"""
self.plugins = []
self.hooks = defaultdict(Hook)
def get_plugins (self, list_disabled = True):
"""
Returns the plugins.
:param list_disabled: Also list disabled plugins.
:type list_disabled: boolean
:rtype: iter<`Plugin`>
"""
return (x for x in self.plugins if (x.enabled or list_disabled))
def load (self):
"""
Load the plugins.
This method scans the `portato.constants.PLUGIN_DIR` for python modules and tries to load them. If the modules are real plugins,
they have called `register` and thus the plugins are added.
"""
# look them up
plugins = []
for f in os.listdir(PLUGIN_DIR):
path = osp.join(PLUGIN_DIR, f)
if osp.isdir(path):
if osp.isfile(osp.join(path, "__init__.py")):
plugins.append(f)
else:
debug("'%s' is not a plugin: __init__.py missing", path)
else:
if f.endswith(".py"):
plugins.append(f[:-3])
elif f.endswith(".pyc") or f.endswith(".pyo"):
pass # ignore .pyc and .pyo
else:
debug("'%s' is not a plugin: not a .py file", path)
# some magic ...
plugin_module.__path__.insert(0, PLUGIN_DIR.rstrip("/")) # make the plugins loadable as "portato.plugins.name"
# add Plugin and register to the builtins, so the plugins always have the correct version :)
plugin_module.__builtins__["Plugin"] = Plugin
plugin_module.__builtins__["WidgetPlugin"] = WidgetPlugin
plugin_module.__builtins__["register"] = register
for p in plugins: # import them
try:
exec "from portato.plugins import %s" % p in {}
except PluginLoadException, e:
error(_("Loading plugin '%(plugin)s' failed: %(error)s"), {"plugin" : p, "error" : e.message})
except:
tb = traceback.format_exc()
error(_("Loading plugin '%(plugin)s' failed: %(error)s"), {"plugin" : p, "error" : tb})
self._organize()
def load_widgets(self, window):
for p in self.plugins:
if isinstance(p, WidgetPlugin):
p._widget_init(window)
for w in p.widgets:
WidgetSlot.slots[w.slot].add_widget(w)
info(_("Widgets of plugin '%s' loaded."), p.name)
def add (self, plugin, disable = False):
"""
Adds a plugin to the internal list.
:Parameters:
plugin : `Plugin`
``Plugin`` subclass or instance to add. If a class is passed, it is instantiated.
disable : boolean
Disable the plugin.
:raise PluginLoadException: passed plugin is not of class `Plugin`
"""
if callable(plugin) and issubclass(plugin, Plugin):
p = plugin(disable = disable) # need an instance and not the class
elif isinstance(plugin, Plugin):
p = plugin
if disable:
p.status = p.STAT_HARD_DISABLED
else:
raise PluginLoadException, "Is neither a subclass nor an instance of Plugin."
p._init()
self.plugins.append(p)
if p.status == p.STAT_HARD_DISABLED:
msg = _("Plugin is disabled!")
elif p._unresolved_deps:
msg = _("Plugin has unresolved dependencies - disabled!")
else:
msg = ""
info("%s %s", _("Plugin '%s' loaded.") % p.name, msg)
def hook (self, hook, *hargs, **hkwargs):
"""
The decorator to use in the program.
All parameters except ``hook`` are passed to plugins.
:param hook: the name of the hook
:type hook: string
"""
def hook_decorator (func):
"""
The real decorator.
"""
h = self.hooks[hook]
active = Hook()
# remove disabled
for type in ("before", "after"):
calls = getattr(h, type)
aCalls = getattr(active, type)
for call in calls:
if call.plugin.enabled:
aCalls.append(call)
if h.override and h.override.plugin.enabled:
active.override = h.override
@wraps(func)
def wrapper (*args, **kwargs):
ret = None
# before
for call in active.before:
debug("Accessing hook '%(hook)s' of plugin '%(plugin)s' (before).", {"hook" : hook, "plugin": call.plugin.name})
call.call(*hargs, **hkwargs)
if active.override: # override
info(_("Overriding hook '%(hook)s' with plugin '%(plugin)s'."), {"hook": hook, "plugin": active.override.plugin.name})
ret = active.override.call(*hargs, **hkwargs)
else: # normal
ret = func(*args, **kwargs)
# after
for call in active.after:
debug("Accessing hook '%(hook)s' of plugin '%(plugin)s' (after).", {"hook": hook, "plugin": call.plugin.name})
call.call(*hargs, **hkwargs)
return ret
return wrapper
return hook_decorator
def _organize (self):
"""
Organizes the lists of `Call` in a way, that all dependencies are fullfilled.
"""
unresolved_before = defaultdict(list)
unresolved_after = defaultdict(list)
star_before = defaultdict(Hook) # should be _before_ all other
star_after = defaultdict(Hook) # should be _after_ all other
for plugin in self.plugins: # plugins
for call in plugin.calls: # hooks in plugin
if call.type == "before":
if call.dep is None: # no dependency -> straight add
self.hooks[call.hook].before.append(call)
elif call.dep == "*":
self.hooks[call.hook].before.insert(0, call)
elif call.dep == "-*":
star_before[call.hook].append(call)
else:
named = [x.plugin.name for x in self.hooks[call.hook].before]
if call.dep in named:
self.hooks[call.hook].before.insert(named.index(call.dep), call)
else:
unresolved_before[call.hook].append(call)
elif call.type == "after":
if call.dep is None: # no dependency -> straight add
self.hooks[call.hook].after.append(call)
elif call.dep == "*":
star_after[call.hook].append(call)
elif call.dep == "-*":
self.hooks[call.hook].after.insert(0, call)
else:
named = [x.plugin.name for x in self.hooks[call.hook].after]
if call.dep in named:
self.hooks[call.hook].after.insert(named.index(call.dep)+1, call)
else:
unresolved_after[call.hook].append(call)
# type = "override"
elif call.type == "override":
if self.hooks[call.hook].override:
warning(_("For hook '%(hook)s' an override is already defined by plugin '%(plugin)s'!"), {"hook": call.hook, "plugin": self.hooks[call.hook].override.plugin.name})
warning(_("It is now replaced by the one from plugin '%s'!"), call.plugin.name)
self.hooks[call.hook].override = call
continue
self._resolve_unresolved(unresolved_before, unresolved_after)
for hook, calls in star_before.iteritems():
self.hooks[hook].before.extend(calls) # append the list
for hook, calls in star_after.iteritems():
self.hooks[hook].after.extend(calls) # append the list
def _resolve_unresolved (self, before, after):
def resolve(hook, list, type, add):
if not list:
return
callList = getattr(self.hooks[hook], type)
named = [x.plugin.name for x in callList]
while list and named:
newNamed = [] # use newNamed, so in each iteration only the plugins inserted last are searched
for call in list[:]:
if call.dep in named:
callList.insert(named.index(call.dep)+add, call)
list.remove(call)
newNamed.append(call.plugin.name)
named = newNamed
for l in list:
callList.append(l)
info(_("Dependant '%(dep)s' for '%(hook)s' in plugin '%(plugin)s' not found! Adding nevertheless."), {"hook": hook, "plugin": l.plugin.name, "dep": l.dep})
for hook in before:
resolve(hook, before[hook], "before", 0)
for hook in after:
resolve(hook, after[hook], "after", 1)
__plugins = None
def load_plugins():
"""
Loads the plugins.
"""
global __plugins
if __plugins is None:
__plugins = PluginQueue()
__plugins.load()
def load_plugin_widgets(window):
"""
Loads the widgets of the plugins.
"""
if __plugins is not None:
__plugins.load_widgets(window)
def get_plugin_queue():
"""
Returns the actual `PluginQueue`. If it is ``None``, they are not being loaded yet.
:rtype: `PluginQueue` or ``None``"""
return __plugins
def hook(hook, *args, **kwargs):
"""
Shortcut to `PluginQueue.hook`. If no `PluginQueue` is loaded, this does nothing.
"""
if __plugins is None:
def pseudo_decorator(f):
return f
return pseudo_decorator
else:
return __plugins.hook(hook, *args, **kwargs)
def dummy_hook (h, *args, **kwargs):
"""
Creates a dummy hook, i.e. a hook which is only needed to trigger something in the plugins, but does nothing for itself.
"""
if __plugins is None:
pass
else:
def dummy ():
pass
hook(h, *args, **kwargs)(dummy)()
def register (plugin, disable = False):
"""
Registers a plugin.
:see: `PluginQueue.add`
"""
if __plugins is not None:
__plugins.add(plugin, disable)
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