Fix #2337 (search the themes the same way than plugins)

- Load the themes from:
    1 - The sources found in the directory ../data/themes/ (if it
    exists)
    2 - The user-defined dir (or ~/.local/blah)
    3 - The poezio_themes package if found

- Also fix some potential issues with the plugins importer

setup.py

@@ -40,8 +40,8 @@ setup(name="poezio",
                        'Programming Language :: Python :: 3',
                     ],
        keywords = ['jabber', 'xmpp', 'client', 'chat', 'im', 'console'],
-       packages = ['poezio', 'poezio_plugins', 'poezio_plugins.gpg'],
-       package_dir = {'poezio': 'src', 'poezio_plugins': 'plugins'},
+       packages = ['poezio', 'poezio_plugins', 'poezio_plugins.gpg', 'poezio_themes'],
+       package_dir = {'poezio': 'src', 'poezio_plugins': 'plugins', 'poezio_themes': 'data/themes'},
        package_data = {'poezio': ['default_config.cfg']},
        scripts = ['scripts/poezio'],
        data_files = [('share/poezio/themes/', ['data/themes/dark.py']),

src/core.py

@@ -301,6 +301,7 @@ class Core(object):
         self.add_configuration_handler("plugins_conf_dir", self.on_plugins_conf_dir_config_change)
         self.add_configuration_handler("connection_timeout_delay", self.xmpp.set_keepalive_values)
         self.add_configuration_handler("connection_check_interval", self.xmpp.set_keepalive_values)
+        self.add_configuration_handler("themes_dir", theming.update_themes_dir)
         self.add_configuration_handler("", self.on_any_config_change)
 
     def on_any_config_change(self, option, value):

src/plugin_manager.py

@@ -62,8 +62,6 @@ else:
     if poezio_plugins.__path__:
         load_path.append(poezio_plugins.__path__[0])
 
-sys.path.extend(load_path)
-
 if version_info[1] >= 3: # 3.3 & >
     from importlib import machinery
     finder = machinery.PathFinder()
@@ -111,7 +109,7 @@ class PluginManager(object):
                     imp.acquire_lock()
                     module = imp.load_module(name, file, filename, info)
             else: # 3.3 & >
-                loader = finder.find_module(name)
+                loader = finder.find_module(name, load_path)
                 if not loader:
                     self.core.information('Could not find plugin')
                     return
@@ -324,9 +322,9 @@ class PluginManager(object):
 
     def on_plugins_dir_change(self, new_value):
         global plugins_dir
-        if plugins_dir in sys.path:
-            sys.path.remove(plugins_dir)
-        sys.path.append(new_value)
+        if plugins_dir in load_path:
+            load_path.remove(plugins_dir)
+        load_path.insert(0, new_value)
         plugins_dir = new_value
 
     def on_plugins_conf_dir_change(self, new_value):

src/theming.py

@@ -67,6 +67,12 @@ from config import config
 import curses
 import imp
 import os
+from os import path
+from sys import version_info
+
+if version_info[1] >= 3:
+    from importlib import machinery
+    finder = machinery.PathFinder()
 
 class Theme(object):
     """
@@ -319,6 +325,8 @@ table_256_to_16 = [
          8,  8,  8,  8,  7,  7,  7,  7,  7,  7, 15, 15, 15, 15, 15, 15
 ]
 
+load_path = []
+
 def color_256_to_16(color):
     if color == -1:
         return color
@@ -384,29 +392,77 @@ def get_theme():
     """
     return theme
 
-def reload_theme():
-    themes_dir = config.get('themes_dir', '')
-    themes_dir = themes_dir or\
-        os.path.join(os.environ.get('XDG_DATA_HOME') or\
-                         os.path.join(os.environ.get('HOME'), '.local', 'share'),
-                     'poezio', 'themes')
-    themes_dir = os.path.expanduser(themes_dir)
+def update_themes_dir(option=None, value=None):
+    global load_path
+    load_path = []
+
+    # import from the git sources
+    default_dir = path.join(
+            path.dirname(path.dirname(__file__)),
+            'data/themes')
+    if path.exists(default_dir):
+        load_path.append(default_dir)
+
+    # import from the user-defined prefs
+    themes_dir = path.expanduser(
+            value or
+            config.get('themes_dir', '') or
+            path.join(os.environ.get('XDG_DATA_HOME') or
+                path.join(os.environ.get('HOME'), '.local', 'share'),
+                'poezio', 'themes')
+            )
     try:
         os.makedirs(themes_dir)
-    except OSError:
+    except OSError as e:
+        if e.errno != 17:
+            log.error('Unable to create the themes dir (%s)', themes_dir)
+        else:
+            load_path.append(themes_dir)
+    else:
+        load_path.append(themes_dir)
+
+    # system-wide import
+    try:
+        import poezio_themes
+    except:
         pass
+    else:
+        load_path.append(poezio_themes.__path__[0])
+
+def reload_theme():
     theme_name = config.get('theme', 'default')
     global theme
     if theme_name == 'default' or not theme_name.strip():
         theme = Theme()
         return
+    new_theme = None
+    exc = None
     try:
-        file_path  = os.path.join(themes_dir, theme_name)+'.py'
-        log.debug('Theme file to load: %s' %(file_path,))
-        new_theme = imp.load_source('theme', os.path.join(themes_dir, theme_name)+'.py')
+        if version_info[1] < 3:
+            file, filename, info = imp.find_module(theme_name, load_path)
+            imp.acquire_lock()
+            new_theme = imp.load_module(them_name, file, filename, info)
+        else:
+            loader = finder.find_module(theme_name, load_path)
+            if not loader:
+                return
+            new_theme = loader.load_module()
     except Exception as e:
-        return 'Failed to load theme: %s' % (e,)
-    theme = new_theme.theme
+        log.error('Failed to load the theme %s', theme_name, exc_info=True)
+        exc = e
+    finally:
+        if version_info[1] < 3:
+            imp.release_lock()
+
+    if not new_theme:
+        return 'Failed to load theme: %s' % exc
+
+    if hasattr(new_theme, 'theme'):
+        theme = new_theme.theme
+    else:
+        return 'No theme present in the theme file'
+
+update_themes_dir()
 
 if __name__ == '__main__':
     """