[core/theme] Add support for icon themes

Allow sub-themes ("iconsets") to be merged into the "main" theme. That
way, effectively, it's possible to define colors and icons in separate
JSON files.

see #23

bumblebee/theme.py

@@ -1,6 +1,7 @@
 """Theme support"""
 
 import os
+import copy
 import json
 
 import bumblebee.error
@@ -12,11 +13,13 @@ def theme_path():
 class Theme(object):
     """Represents a collection of icons and colors"""
     def __init__(self, name):
-        theme = self.load(name)
         self._init(self.load(name))
 
     def _init(self, data):
         """Initialize theme from data structure"""
+        for iconset in data.get("icons", []):
+            self._merge(data, self._load_icons(iconset))
+        self._theme = data
         self._defaults = data.get("defaults", {})
 
     def prefix(self, widget):
@@ -31,10 +34,14 @@ class Theme(object):
         theme = json.loads(data)
         self._init(theme)
 
-    def load(self, name):
+    def _load_icons(self, name):
+        path = "{}/icons/".format(theme_path())
+        return self.load(name, path=path)
+
+    def load(self, name, path=theme_path()):
         """Load and parse a theme file"""
-        path = theme_path()
         themefile = "{}/{}.json".format(path, name)
+
         if os.path.isfile(themefile):
             try:
                 with open(themefile) as data:
@@ -45,9 +52,31 @@ class Theme(object):
             raise bumblebee.error.ThemeLoadError("no such theme: {}".format(name))
 
     def _get(self, widget, name, default=None):
-        value = default
-        value = self._defaults.get(name, value)
+
+        module_theme = self._theme.get(widget.module(), {})
+
+        value = self._defaults.get(name, default)
+        value = module_theme.get(name, value)
 
         return value
 
+    # algorithm copied from
+    # http://blog.impressiver.com/post/31434674390/deep-merge-multiple-python-dicts
+    # nicely done :)
+    def _merge(self, target, *args):
+        if len(args) > 1:
+            for item in args:
+                self._merge(item)
+            return target
+
+        item = args[0]
+        if not isinstance(item, dict):
+            return item
+        for key, value in item.items():
+            if key in target and isinstance(target[key], dict):
+                self._merge(target[key], value)
+            else:
+                target[key] = copy.deepcopy(value)
+        return target
+
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

tests/test_theme.py

@@ -9,8 +9,15 @@ class TestTheme(unittest.TestCase):
     def setUp(self):
         self.nonexistentThemeName = "no-such-theme"
         self.invalidThemeName = "invalid"
-        self.validThemeName = "solarized-powerline"
+        self.validThemeName = "test"
         self.someWidget = MockWidget("foo")
+        self.theme = Theme(self.validThemeName)
+
+        self.widgetTheme = "test-widget"
+        self.defaultPrefix = "default-prefix"
+        self.defaultSuffix = "default-suffix"
+        self.widgetPrefix = "widget-prefix"
+        self.widgetSuffix = "widget-suffix"
 
     def test_load_valid_theme(self):
         try:
@@ -26,14 +33,14 @@ class TestTheme(unittest.TestCase):
         with self.assertRaises(ThemeLoadError):
             Theme(self.invalidThemeName)
 
-    def test_prefix(self):
-        theme = Theme(self.validThemeName)
-        theme.loads('{"defaults": { "prefix": "test" }}')
-        self.assertEquals(theme.prefix(self.someWidget), "test")
+    def test_default_prefix(self):
+        self.assertEquals(self.theme.prefix(self.someWidget), self.defaultPrefix)
 
-    def test_suffix(self):
-        theme = Theme(self.validThemeName)
-        theme.loads('{"defaults": { "suffix": "test" }}')
-        self.assertEquals(theme.suffix(self.someWidget), "test")
+    def test_default_suffix(self):
+        self.assertEquals(self.theme.suffix(self.someWidget), self.defaultSuffix)
+
+    def test_widget_prefix(self):
+        self.someWidget.set_module(self.widgetTheme)
+        self.assertEquals(self.theme.prefix(self.someWidget), self.widgetPrefix)
 
 # vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4

tests/util.py

@@ -22,10 +22,17 @@ class MockOutput(object):
 class MockWidget(object):
     def __init__(self, text):
         self._text = text
+        self._module = None
+
+    def set_module(self, name):
+        self._module = name
 
     def update(self, widgets):
         pass
 
+    def module(self):
+        return self._module
+
     def full_text(self):
         return self._text
 

themes/icons/test.json

@@ -0,0 +1,6 @@
+{
+	"test-widget": {
+		"prefix": "widget-prefix",
+		"suffix": "widget-suffix"
+	}
+}

themes/test.json

@@ -0,0 +1,7 @@
+{
+	"icons": [ "test" ],
+	"defaults": {
+		"prefix": "default-prefix",
+		"suffix": "default-suffix"
+	}
+}