1 files changed, 81 insertions, 0 deletions
diff --git a/layout/style/GenerateComputedDOMStyleGenerated.py b/layout/style/GenerateComputedDOMStyleGenerated.py
new file mode 100644
index 0000000000..1c3de618fc
--- /dev/null
+++ b/layout/style/GenerateComputedDOMStyleGenerated.py
@@ -0,0 +1,81 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this file,
+# You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import runpy
+
+FILE = """/* THIS IS AN AUTOGENERATED FILE.  DO NOT EDIT */
+
+/* processed file that defines entries for nsComputedDOMStyle, designed
+   to be #included in nsComputedDOMStyle.cpp */
+
+static constexpr size_t kEntryIndices[eCSSProperty_COUNT] = {{
+  {indices}
+}};
+
+{asserts}
+
+static constexpr Entry kEntries[eCSSProperty_COUNT] = {{
+  {entries}
+}};
+"""
+
+
+def generate(output, dataFile):
+    def order_key(p):
+        # Put prefixed properties after normal properties.
+        # The spec is unclear about this, and Blink doesn't have any sensible
+        # order at all, so it probably doesn't matter a lot. But originally
+        # Gecko put then later so we do so as well. See w3c/csswg-drafts#2827.
+        order = p.name.startswith("-")
+        return (order, p.name)
+
+    def has_cpp_getter(p):
+        if not "ExposedOnGetCS" in p.flags:
+            return False
+        if "SerializedByServo" in p.flags:
+            return False
+        if p.type() == "longhand" and "IsLogical" in p.flags:
+            return False
+        return True
+
+    def getter_entry(p):
+        if has_cpp_getter(p):
+            return "DoGet" + p.method
+        # Put a dummy getter here instead of nullptr because MSVC seems
+        # to have bug which ruins the table when we put nullptr for
+        # pointer-to-member-function. See bug 1471426.
+        return "DummyGetter"
+
+    properties = runpy.run_path(dataFile)["data"]
+
+    entries = []
+    indices = []
+    asserts = []
+    index_map = {}
+    non_aliases = list(filter(lambda p: p.type() != "alias", properties))
+    for i, p in enumerate(sorted(non_aliases, key=order_key)):
+        can_be_exposed = "true" if "ExposedOnGetCS" in p.flags else "false"
+        entries.append(
+            "{{ eCSSProperty_{}, {}, &nsComputedDOMStyle::{}}}".format(
+                p.id, can_be_exposed, getter_entry(p)
+            )
+        )
+        index_map[p.id] = i
+        i += 1
+
+    for i, p in enumerate(non_aliases):
+        indices.append(str(index_map[p.id]))
+        asserts.append(
+            'static_assert(size_t(eCSSProperty_{}) == {}, "");'.format(p.id, i)
+        )
+
+    assert len(indices) == len(entries)
+
+    output.write(
+        FILE.format(
+            indices=", ".join(indices),
+            entries=",\n    ".join(entries),
+            asserts="\n".join(asserts),
+        )
+    )