Add SphinxFactory class to simplify application class

sphinx/application.py

@@ -26,19 +26,18 @@ from six.moves import cStringIO
 from docutils import nodes
 from docutils.parsers.rst import convert_directive_function, \
     directives, roles
-from pkg_resources import iter_entry_points
 
 import sphinx
 from sphinx import package_dir, locale
 from sphinx.config import Config
-from sphinx.errors import SphinxError, ExtensionError, VersionRequirementError, \
+from sphinx.errors import ConfigError, ExtensionError, VersionRequirementError
-    ConfigError
 from sphinx.domains import ObjType
 from sphinx.domains.std import GenericObject, Target, StandardDomain
 from sphinx.deprecation import RemovedInSphinx17Warning, RemovedInSphinx20Warning
 from sphinx.environment import BuildEnvironment
 from sphinx.events import EventManager
 from sphinx.extension import load_extension, verify_required_extensions
+from sphinx.factory import SphinxFactory
 from sphinx.io import SphinxStandaloneReader
 from sphinx.locale import _
 from sphinx.roles import XRefRole
@@ -124,9 +123,9 @@ class Sphinx(object):
         self._additional_source_parsers = {}    # type: Dict[unicode, Parser]
         self._setting_up_extension = ['?']      # type: List[unicode]
         self.domains = {}                       # type: Dict[unicode, Type[Domain]]
-        self.builderclasses = {}                # type: Dict[unicode, Type[Builder]]
         self.builder = None                     # type: Builder
         self.env = None                         # type: BuildEnvironment
+        self.factory = SphinxFactory()
         self.enumerable_nodes = {}              # type: Dict[nodes.Node, Tuple[unicode, Callable]]  # NOQA
         self.post_transforms = []               # type: List[Transform]
         self.html_themes = {}                   # type: Dict[unicode, unicode]
@@ -301,28 +300,17 @@ class Sphinx(object):
                     logger.info(_('failed: %s'), err)
                 self._init_env(freshenv=True)
 
-    def preload_builder(self, buildername):
+    def preload_builder(self, name):
         # type: (unicode) -> None
-        if buildername is None:
+        self.factory.preload_builder(self, name)
-            return
 
-        if buildername not in self.builderclasses:
+    def create_builder(self, name):
-            entry_points = iter_entry_points('sphinx.builders', buildername)
-            try:
-                entry_point = next(entry_points)
-            except StopIteration:
-                raise SphinxError(_('Builder name %s not registered or available'
-                                    ' through entry point') % buildername)
-            load_extension(self, entry_point.module_name)
-
-    def create_builder(self, buildername):
         # type: (unicode) -> Builder
-        if buildername is None:
+        if name is None:
-            buildername = 'html'
+            logger.info(_('No builder selected, using default: html'))
-        if buildername not in self.builderclasses:
+            name = 'html'
-            raise SphinxError(_('Builder name %s not registered') % buildername)
 
-        return self.builderclasses[buildername](self)
+        return self.factory.create_builder(self, name)
 
     def _init_builder(self):
         # type: () -> None
@@ -516,13 +504,7 @@ class Sphinx(object):
     def add_builder(self, builder):
         # type: (Type[Builder]) -> None
         logger.debug('[app] adding builder: %r', builder)
-        if not hasattr(builder, 'name'):
+        self.factory.add_builder(builder)
-            raise ExtensionError(_('Builder class %s has no "name" attribute')
-                                 % builder)
-        if builder.name in self.builderclasses:
-            raise ExtensionError(_('Builder %r already exists (in module %s)') %
-                                 (builder.name, self.builderclasses[builder.name].__module__))
-        self.builderclasses[builder.name] = builder
 
     def add_config_value(self, name, default, rebuild, types=()):
         # type: (unicode, Any, Union[bool, unicode], Any) -> None

sphinx/factory.py

@@ -0,0 +1,59 @@
+# -*- coding: utf-8 -*-
+"""
+    sphinx.factory
+    ~~~~~~~~~~~~~~
+
+    Sphinx component factory.
+
+    Gracefully adapted from the TextPress system by Armin.
+
+    :copyright: Copyright 2007-2016 by the Sphinx team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+from __future__ import print_function
+from pkg_resources import iter_entry_points
+
+from sphinx.errors import ExtensionError, SphinxError
+from sphinx.extension import load_extension
+from sphinx.locale import _
+
+if False:
+    # For type annotation
+    from typing import Dict, Type  # NOQA
+    from sphinx.application import Sphinx  # NOQA
+    from sphinx.builders import Builder  # NOQA
+
+
+class SphinxFactory(object):
+    def __init__(self):
+        self.builders = {}  # type: Dict[unicode, Type[Builder]]
+
+    def add_builder(self, builder):
+        # type: (Type[Builder]) -> None
+        if not hasattr(builder, 'name'):
+            raise ExtensionError(_('Builder class %s has no "name" attribute') % builder)
+        if builder.name in self.builders:
+            raise ExtensionError(_('Builder %r already exists (in module %s)') %
+                                 (builder.name, self.builders[builder.name].__module__))
+        self.builders[builder.name] = builder
+
+    def preload_builder(self, app, name):
+        # type: (Sphinx, unicode) -> None
+        if name is None:
+            return
+
+        if name not in self.builders:
+            entry_points = iter_entry_points('sphinx.builders', name)
+            try:
+                entry_point = next(entry_points)
+            except StopIteration:
+                raise SphinxError(_('Builder name %s not registered or available'
+                                    ' through entry point') % name)
+            load_extension(app, entry_point.module_name)
+
+    def create_builder(self, app, name):
+        # type: (Sphinx, unicode) -> Builder
+        if name not in self.builders:
+            raise SphinxError(_('Builder name %s not registered') % name)
+
+        return self.builders[name](app)