[core] restructure to allow PIP packaging

OK - so I have to admit I *hate* the fact that PIP seems to require a
subdirectory named like the library.

But since the PIP package is something really nifty to have (thanks to
@tony again!!!), I updated the codebase to hopefully conform with what
PIP expects. Testruns so far look promising...

bumblebee_status/modules/contrib/caffeine.py

@@ -0,0 +1,117 @@
+# pylint: disable=C0111,R0903,W0212
+
+"""Enable/disable automatic screen locking.
+
+Requires the following executables:
+    * xdg-screensaver
+    * xdotool
+    * xprop (as dependency for xdotool)
+    * notify-send
+
+contributed by `TheEdgeOfRage <https://github.com/TheEdgeOfRage>`_ - many thanks!
+"""
+
+import logging
+import os
+import shutil
+import psutil
+
+import core.module
+import core.widget
+import core.input
+import core.decorators
+
+import util.cli
+
+
+class Module(core.module.Module):
+    @core.decorators.every(minutes=10)
+    def __init__(self, config, theme):
+        super().__init__(config, theme, core.widget.Widget(""))
+
+        self.__active = False
+        self.__xid = None
+
+        core.input.register(self, button=core.input.LEFT_MOUSE, cmd=self.__toggle)
+
+    def __check_requirements(self):
+        requirements = ["xdotool", "xprop", "xdg-screensaver"]
+        missing = []
+        for tool in requirements:
+            if not shutil.which(tool):
+                missing.append(tool)
+        return missing
+
+    def __get_i3bar_xid(self):
+        xid = (
+            util.cli.execute("xdotool search --class 'i3bar'")
+            .partition("\n")[0]
+            .strip()
+        )
+        if xid.isdigit():
+            return xid
+        logging.warning("Module caffeine: xdotool couldn't get X window ID of 'i3bar'.")
+        return None
+
+    def __notify(self):
+        if not shutil.which("notify-send"):
+            return
+
+        if self.__active:
+            util.cli.execute("notify-send 'Consuming caffeine'")
+        else:
+            util.cli.execute("notify-send 'Out of coffee'")
+
+    def _suspend_screensaver(self):
+        self.__xid = self.__get_i3bar_xid()
+        if self.__xid is None:
+            return False
+
+        pid = os.fork()
+        if pid == 0:
+            os.setsid()
+            util.cli.execute("xdg-screensaver suspend {}".format(self.__xid))
+            os._exit(0)
+        else:
+            os.waitpid(pid, 0)
+        return True
+
+    def __resume_screensaver(self):
+        success = True
+        xprop_path = shutil.which("xprop")
+        pids = [
+            p.pid
+            for p in psutil.process_iter()
+            if p.cmdline() == [xprop_path, "-id", str(self.__xid), "-spy"]
+        ]
+        for pid in pids:
+            try:
+                os.kill(pid, 9)
+            except OSError:
+                success = False
+        return success
+
+    def state(self, _):
+        if self.__active:
+            return "activated"
+        return "deactivated"
+
+    def __toggle(self, _):
+        missing = self.__check_requirements()
+        if missing:
+            logging.warning("Could not run caffeine - missing %s!", ", ".join(missing))
+            return
+
+        self.__active = not self.__active
+        if self.__active:
+            success = self._suspend_screensaver()
+        else:
+            success = self.__resume_screensaver()
+
+        if success:
+            self.__notify()
+        else:
+            self.__active = not self.__active
+
+
+# vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4