Add support for nowplaying-tf, which provides better format strings

This is added with the tf_format config, which will override format if
it is set. This makes the call "deadbeef --nowplaying-tf <tf_format>"
and displays the output directly. This output should now also support
unicode, regardless of Python version.

There is also the tf_format_if_stopped, a boolean config that
configures whether or not the tf_format output should be displayed
even if deadbeef isn't playing anything.

bumblebee/modules/deadbeef.py

@@ -1,9 +1,10 @@
 # pylint: disable=C0111,R0903
 
-"""Displays the current song being played in DeaDBeeF and
-provides some media control bindings.
-Left click toggles pause, scroll up skips the current song,
-scroll down returns to the previous song.
+"""Displays the current song being played in DeaDBeeF and provides
+some media control bindings.
+Left click toggles pause, scroll up skips the current song, scroll
+down returns to the previous song.
+
 Requires the following library:
     * subprocess
 Parameters:
@@ -11,12 +12,27 @@ Parameters:
                           Available values are: {artist}, {title}, {album}, {length},
                                                 {trackno}, {year}, {comment},
                                                 {copyright}, {time}
+                          This is deprecated, but much simpler.
+    * deadbeef.tf_format: A foobar2000 title formatting-style format string.
+                          These can be much more sophisticated than the standard
+                          format strings. This is off by default, but specifying
+                          any tf_format will enable it. If both deadbeef.format
+                          and deadbeef.tf_format are specified, deadbeef.tf_format
+                          takes priority.
+    * deadbeef.tf_format_if_stopped: Controls whether or not the tf_format format
+                          string should be displayed even if no song is paused or
+                          playing. This could be useful if you want to implement
+                          your own stop strings with the built in logic. Any non-
+                          null value will enable this (by default the module will
+                          hide itself when the player is stopped).
     * deadbeef.previous:  Change binding for previous song (default is left click)
     * deadbeef.next:      Change binding for next song (default is right click)
     * deadbeef.pause:     Change binding for toggling pause (default is middle click)
     Available options for deadbeef.previous, deadbeef.next and deadbeef.pause are:
         LEFT_CLICK, RIGHT_CLICK, MIDDLE_CLICK, SCROLL_UP, SCROLL_DOWN
+
 """
+import sys
 
 import bumblebee.input
 import bumblebee.output
@@ -43,11 +59,14 @@ class Module(bumblebee.engine.Module):
         
         self._song = ""
         self._format = self.parameter("format", "{artist} - {title}")
+        self._tf_format = self.parameter("tf_format", "")
+        self._show_tf_when_stopped = bool(self.parameter("tf_format_if_stopped", ""))
         prev_button = self.parameter("previous", "LEFT_CLICK")
         next_button = self.parameter("next", "RIGHT_CLICK")
         pause_button = self.parameter("pause", "MIDDLE_CLICK")
 
         self.now_playing = ["deadbeef", "--nowplaying", "%a;%t;%b;%l;%n;%y;%c;%r;%e"]
+        self.now_playing_tf = ["deadbeef", "--nowplaying-tf", ""]
         cmd = "deadbeef "
 
         engine.input.register_callback(self, button=buttons[prev_button],
@@ -59,15 +78,34 @@ class Module(bumblebee.engine.Module):
 
     @scrollable
     def deadbeef(self, widget):
-        return str(self._song)
+        return self.string_song
 
     def hidden(self):
-        return str(self._song) == ""
+        return self.string_song == ""
 
     def update(self, widgets):
         try:
-            deadbeef = subprocess.Popen(self.now_playing,stdin=subprocess.PIPE,stdout=subprocess.PIPE)
-            data = deadbeef.communicate()[0]
+            if self._tf_format == "": # no tf format set, use the old style
+                return self.update_standard(widgets)
+            return self.update_tf(widgets)
+        except Exception:
+            self._song = "error"
+
+    def update_tf(self, widgets):
+        if not self._show_tf_when_stopped:
+            ## check if the player is paused or playing
+            self.now_playing_tf[-1] = "%isplaying%%ispaused%"
+            data = read_process(self.now_playing_tf)
+            if data == "":
+                self._song = ""
+                return
+        ## perform the actual query -- these can be much more sophisticated
+        self.now_playing_tf[-1] = self._tf_format
+        data = read_process(self.now_playing_tf)
+        self._song = data
+
+    def update_standard(self, widgets):
+        data = read_process(self.now_playing)
         if data == "nothing":
             self._song = ""
         else:
@@ -81,7 +119,19 @@ class Module(bumblebee.engine.Module):
                                              comment=data[6],
                                              copyright=data[7],
                                              time=data[8])
-        except Exception:
-            self._song = ""
+
+    @property
+    def string_song(self):
+        """\
+Returns the current song as a string, either as a unicode() (Python <
+3) or a regular str() (Python >= 3)
+        """
+        if sys.version_info.major < 3:
+            return unicode(self._song)
+        return str(self._song)
+
+def read_process(command):
+    proc = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    return proc.stdout.read()
 
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