[meld] Break out style handling helpers into new module

[Kai Willadsen <kaiw src gnome org>]

commit de10bd839b4494d11c26a9a3dcb5177efdb597ba
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Jun 30 09:01:23 2019 +1000

    Break out style handling helpers into new module

 meld/actiongutter.py        |   2 +-
 meld/chunkmap.py            |   2 +-
 meld/gutterrendererchunk.py |   2 +-
 meld/linkmap.py             |   2 +-
 meld/misc.py                |  96 ----------------------------------
 meld/sourceview.py          |   2 +-
 meld/style.py               | 122 ++++++++++++++++++++++++++++++++++++++++++++
 meld/tree.py                |   2 +-
 po/POTFILES.in              |   1 +
 9 files changed, 129 insertions(+), 102 deletions(-)
---
diff --git a/meld/actiongutter.py b/meld/actiongutter.py
index deb4b868..3d7740d2 100644
--- a/meld/actiongutter.py
+++ b/meld/actiongutter.py
@@ -23,8 +23,8 @@ from gi.repository import Gtk
 
 from meld.conf import _
 from meld.const import ActionMode, ChunkAction
-from meld.misc import get_common_theme
 from meld.settings import meldsettings
+from meld.style import get_common_theme
 from meld.ui.gtkcompat import get_style
 
 
diff --git a/meld/chunkmap.py b/meld/chunkmap.py
index 4f489a82..c33d855e 100644
--- a/meld/chunkmap.py
+++ b/meld/chunkmap.py
@@ -22,8 +22,8 @@ from gi.repository import Gdk
 from gi.repository import GObject
 from gi.repository import Gtk
 
-from meld.misc import get_common_theme
 from meld.settings import meldsettings
+from meld.style import get_common_theme
 from meld.tree import STATE_ERROR, STATE_MODIFIED, STATE_NEW
 
 log = logging.getLogger(__name__)
diff --git a/meld/gutterrendererchunk.py b/meld/gutterrendererchunk.py
index c2a62acd..58d60500 100644
--- a/meld/gutterrendererchunk.py
+++ b/meld/gutterrendererchunk.py
@@ -19,8 +19,8 @@ from gi.repository import Gdk
 from gi.repository import GtkSource
 from gi.repository import Pango
 
-from meld.misc import get_common_theme
 from meld.settings import meldsettings
+from meld.style import get_common_theme
 
 
 def get_background_rgba(renderer):
diff --git a/meld/linkmap.py b/meld/linkmap.py
index f8446206..6996da00 100644
--- a/meld/linkmap.py
+++ b/meld/linkmap.py
@@ -20,8 +20,8 @@ import math
 from gi.repository import Gdk
 from gi.repository import Gtk
 
-from meld.misc import get_common_theme
 from meld.settings import meldsettings
+from meld.style import get_common_theme
 
 
 # Rounded rectangle corner radius for culled changes display
diff --git a/meld/misc.py b/meld/misc.py
index e91bddb8..c727f57f 100644
--- a/meld/misc.py
+++ b/meld/misc.py
@@ -30,7 +30,6 @@ from typing import (
     Callable,
     Generator,
     List,
-    Mapping,
     Optional,
     Pattern,
     Sequence,
@@ -39,10 +38,8 @@ from typing import (
     Union,
 )
 
-from gi.repository import Gdk
 from gi.repository import GLib
 from gi.repository import Gtk
-from gi.repository import GtkSource
 
 from meld.conf import _
 
@@ -163,99 +160,6 @@ def user_critical(
     return wrap
 
 
-MELD_STYLE_SCHEME = "meld-base"
-MELD_STYLE_SCHEME_DARK = "meld-dark"
-
-
-base_style_scheme: Optional[GtkSource.StyleScheme] = None
-
-
-def get_base_style_scheme() -> GtkSource.StyleScheme:
-
-    global base_style_scheme
-
-    if base_style_scheme:
-        return base_style_scheme
-
-    env_theme = GLib.getenv('GTK_THEME')
-    if env_theme:
-        use_dark = env_theme.endswith(':dark')
-    else:
-        gtk_settings = Gtk.Settings.get_default()
-        use_dark = gtk_settings.props.gtk_application_prefer_dark_theme
-
-    # As of 3.28, the global dark theme switch is going away.
-    if not use_dark:
-        from meld.sourceview import MeldSourceView
-        stylecontext = MeldSourceView().get_style_context()
-        background_set, rgba = (
-            stylecontext.lookup_color('theme_bg_color'))
-
-        # This heuristic is absolutely dire. I made it up. There's
-        # literally no basis to this.
-        if background_set and rgba.red + rgba.green + rgba.blue < 1.0:
-            use_dark = True
-
-    base_scheme_name = (
-        MELD_STYLE_SCHEME_DARK if use_dark else MELD_STYLE_SCHEME)
-
-    manager = GtkSource.StyleSchemeManager.get_default()
-    base_style_scheme = manager.get_scheme(base_scheme_name)
-
-    return base_style_scheme
-
-
-def colour_lookup_with_fallback(name: str, attribute: str) -> Gdk.RGBA:
-    from meld.settings import meldsettings
-    source_style = meldsettings.style_scheme
-
-    style = source_style.get_style(name) if source_style else None
-    style_attr = getattr(style.props, attribute) if style else None
-    if not style or not style_attr:
-        base_style = get_base_style_scheme()
-        try:
-            style = base_style.get_style(name)
-            style_attr = getattr(style.props, attribute)
-        except AttributeError:
-            pass
-
-    if not style_attr:
-        import sys
-        print(_(
-            "Couldn’t find colour scheme details for %s-%s; "
-            "this is a bad install") % (name, attribute), file=sys.stderr)
-        sys.exit(1)
-
-    colour = Gdk.RGBA()
-    colour.parse(style_attr)
-    return colour
-
-
-ColourMap = Mapping[str, Gdk.RGBA]
-
-
-def get_common_theme() -> Tuple[ColourMap, ColourMap]:
-    lookup = colour_lookup_with_fallback
-    fill_colours = {
-        "insert": lookup("meld:insert", "background"),
-        "delete": lookup("meld:insert", "background"),
-        "conflict": lookup("meld:conflict", "background"),
-        "replace": lookup("meld:replace", "background"),
-        "error": lookup("meld:error", "background"),
-        "focus-highlight": lookup("meld:current-line-highlight", "foreground"),
-        "current-chunk-highlight": lookup(
-            "meld:current-chunk-highlight", "background")
-    }
-    line_colours = {
-        "insert": lookup("meld:insert", "line-background"),
-        "delete": lookup("meld:insert", "line-background"),
-        "conflict": lookup("meld:conflict", "line-background"),
-        "replace": lookup("meld:replace", "line-background"),
-        "error": lookup("meld:error", "line-background"),
-    }
-    return fill_colours, line_colours
-
-
 def all_same(iterable: Sequence) -> bool:
     """Return True if all elements of the list are equal"""
     sample, has_no_sample = None, True
diff --git a/meld/sourceview.py b/meld/sourceview.py
index 152b31b7..c7735d23 100644
--- a/meld/sourceview.py
+++ b/meld/sourceview.py
@@ -25,8 +25,8 @@ from gi.repository import Gtk
 from gi.repository import GtkSource
 
 from meld.meldbuffer import MeldBuffer
-from meld.misc import colour_lookup_with_fallback, get_common_theme
 from meld.settings import bind_settings, meldsettings, settings
+from meld.style import colour_lookup_with_fallback, get_common_theme
 
 
 log = logging.getLogger(__name__)
diff --git a/meld/style.py b/meld/style.py
new file mode 100644
index 00000000..fc90dd2e
--- /dev/null
+++ b/meld/style.py
@@ -0,0 +1,122 @@
+# Copyright (C) 2002-2006 Stephen Kennedy <stevek gnome org>
+# Copyright (C) 2009 Vincent Legoll <vincent legoll gmail com>
+# Copyright (C) 2012-2019 Kai Willadsen <kai willadsen gmail com>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 2 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+from typing import (
+    Mapping,
+    Optional,
+    Tuple,
+)
+
+from gi.repository import Gdk
+from gi.repository import GLib
+from gi.repository import Gtk
+from gi.repository import GtkSource
+
+from meld.conf import _
+
+MELD_STYLE_SCHEME = "meld-base"
+MELD_STYLE_SCHEME_DARK = "meld-dark"
+
+
+base_style_scheme: Optional[GtkSource.StyleScheme] = None
+
+
+def get_base_style_scheme() -> GtkSource.StyleScheme:
+
+    global base_style_scheme
+
+    if base_style_scheme:
+        return base_style_scheme
+
+    env_theme = GLib.getenv('GTK_THEME')
+    if env_theme:
+        use_dark = env_theme.endswith(':dark')
+    else:
+        gtk_settings = Gtk.Settings.get_default()
+        use_dark = gtk_settings.props.gtk_application_prefer_dark_theme
+
+    # As of 3.28, the global dark theme switch is going away.
+    if not use_dark:
+        from meld.sourceview import MeldSourceView
+        stylecontext = MeldSourceView().get_style_context()
+        background_set, rgba = (
+            stylecontext.lookup_color('theme_bg_color'))
+
+        # This heuristic is absolutely dire. I made it up. There's
+        # literally no basis to this.
+        if background_set and rgba.red + rgba.green + rgba.blue < 1.0:
+            use_dark = True
+
+    base_scheme_name = (
+        MELD_STYLE_SCHEME_DARK if use_dark else MELD_STYLE_SCHEME)
+
+    manager = GtkSource.StyleSchemeManager.get_default()
+    base_style_scheme = manager.get_scheme(base_scheme_name)
+
+    return base_style_scheme
+
+
+def colour_lookup_with_fallback(name: str, attribute: str) -> Gdk.RGBA:
+    from meld.settings import meldsettings
+    source_style = meldsettings.style_scheme
+
+    style = source_style.get_style(name) if source_style else None
+    style_attr = getattr(style.props, attribute) if style else None
+    if not style or not style_attr:
+        base_style = get_base_style_scheme()
+        try:
+            style = base_style.get_style(name)
+            style_attr = getattr(style.props, attribute)
+        except AttributeError:
+            pass
+
+    if not style_attr:
+        import sys
+        print(_(
+            "Couldn’t find colour scheme details for %s-%s; "
+            "this is a bad install") % (name, attribute), file=sys.stderr)
+        sys.exit(1)
+
+    colour = Gdk.RGBA()
+    colour.parse(style_attr)
+    return colour
+
+
+ColourMap = Mapping[str, Gdk.RGBA]
+
+
+def get_common_theme() -> Tuple[ColourMap, ColourMap]:
+    lookup = colour_lookup_with_fallback
+    fill_colours = {
+        "insert": lookup("meld:insert", "background"),
+        "delete": lookup("meld:insert", "background"),
+        "conflict": lookup("meld:conflict", "background"),
+        "replace": lookup("meld:replace", "background"),
+        "error": lookup("meld:error", "background"),
+        "focus-highlight": lookup("meld:current-line-highlight", "foreground"),
+        "current-chunk-highlight": lookup(
+            "meld:current-chunk-highlight", "background")
+    }
+    line_colours = {
+        "insert": lookup("meld:insert", "line-background"),
+        "delete": lookup("meld:insert", "line-background"),
+        "conflict": lookup("meld:conflict", "line-background"),
+        "replace": lookup("meld:replace", "line-background"),
+        "error": lookup("meld:error", "line-background"),
+    }
+    return fill_colours, line_colours
diff --git a/meld/tree.py b/meld/tree.py
index f4d853fe..fcee1601 100644
--- a/meld/tree.py
+++ b/meld/tree.py
@@ -22,7 +22,7 @@ from gi.repository import GLib
 from gi.repository import GObject
 from gi.repository import Pango
 
-from meld.misc import colour_lookup_with_fallback
+from meld.style import colour_lookup_with_fallback
 from meld.treehelpers import SearchableTreeStore
 from meld.vc._vc import (  # noqa: F401
     CONFLICT_BASE, CONFLICT_LOCAL, CONFLICT_MERGED, CONFLICT_OTHER,
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 83c5a543..649d1d73 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -48,6 +48,7 @@ meld/newdifftab.py
 meld/patchdialog.py
 meld/preferences.py
 meld/recent.py
+meld/style.py
 meld/ui/bufferselectors.py
 meld/ui/findbar.py
 meld/ui/historyentry.py