Add rule to ensure <namedColor> matches the asset catalog (lyft#50)

xiblint/__init__.py

@@ -1 +1 @@
-__version__ = '0.9.8'
+__version__ = '0.9.9'

xiblint/rules/color_assets.py

@@ -0,0 +1,82 @@
+from xiblint.rules import Rule
+from xiblint.xibcontext import XibContext
+import glob
+import json
+
+
+class ColorAssets(Rule):
+    def __init__(self, config):
+        asset_catalog_path = config.get('asset_catalog', None)
+        if asset_catalog_path is None:
+            raise SystemExit("error: Asset catalog not found. Please configure 'asset_catalog'.")
+
+        self.assets = glob.glob("{}/**/*.colorset".format(asset_catalog_path))
+
+        if not self.assets:
+            raise SystemExit("error: Failed to load asset catalog at: '{}'".format(asset_catalog_path))
+
+        self.colors = {}
+
+    """
+    Ensures cached named colors match the named colors from an asset catalog.
+
+    Example configuration:
+    {
+      "asset_catalog": "Resources/Color.xcassets"
+    }
+    """
+    def check(self, context):  # type: (XibContext) -> None
+        for element in context.tree.findall(".//namedColor"):
+            name = element.get("name")
+            if not name:
+                context.error(element, "Named color is missing a name.")
+                continue
+
+            expected_color = self._load_color(name)
+            if not expected_color:
+                context.error(element, "Named color '{}' is missing from asset catalog.".format(name))
+                continue
+
+            color_element = element.find("color")
+            if color_element is None:
+                context.error(element, "Named color '{}' is missing color definition.".format(name))
+                continue
+
+            red = color_element.get("red")
+            green = color_element.get("green")
+            blue = color_element.get("blue")
+            alpha = color_element.get("alpha")
+            if not all([red, green, blue, alpha]):
+                context.error(element, "Named color '{}' has invalid color value.".format(name))
+                continue
+
+            color = (float(red), float(green), float(blue), float(alpha))
+
+            if color != expected_color:
+                context.error(element, "Color value for '{}' does not match asset catalog.".format(name))
+
+    def _load_color(self, name):
+        if name in self.colors:
+            return self.colors[name]
+
+        for path in self.assets:
+            if not path.endswith("{}.colorset".format(name)):
+                continue
+
+            with open("{}/Contents.json".format(path)) as json_file:
+                data = json.load(json_file)
+                color = self._load_components(data["colors"][0]["color"]["components"])
+                self.colors[name] = color
+                return color
+
+    def _load_components(self, components):
+        return (self._load_component(components, "red"), self._load_component(components, "green"),
+                self._load_component(components, "blue"), self._load_component(components, "alpha"))
+
+    def _load_component(self, components, key):
+        string = components[key]
+
+        if "." in string:
+            return float(string)
+
+        return float(string) / 255.0