layout/style/GenerateComputedDOMStyleGenerated.py

   1 # This Source Code Form is subject to the terms of the Mozilla Public
   2 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
   3 # You can obtain one at http://mozilla.org/MPL/2.0/.
   4
   5 import runpy
   6
   7 FILE = """/* THIS IS AN AUTOGENERATED FILE.  DO NOT EDIT */
   8
   9 /* processed file that defines entries for nsComputedDOMStyle, designed
  10    to be #included in nsComputedDOMStyle.cpp */
  11
  12 static constexpr size_t kEntryIndices[eCSSProperty_COUNT] = {{
  13   {indices}
  14 }};
  15
  16 {asserts}
  17
  18 static constexpr Entry kEntries[eCSSProperty_COUNT] = {{
  19   {entries}
  20 }};
  21 """
  22
  23
  24 def generate(output, dataFile):
  25     def order_key(p):
  26         # Put prefixed properties after normal properties.
  27         # The spec is unclear about this, and Blink doesn't have any sensible
  28         # order at all, so it probably doesn't matter a lot. But originally
  29         # Gecko put then later so we do so as well. See w3c/csswg-drafts#2827.
  30         order = p.name.startswith("-")
  31         return (order, p.name)
  32
  33     def has_cpp_getter(p):
  34         if not "ExposedOnGetCS" in p.flags:
  35             return False
  36         if "SerializedByServo" in p.flags:
  37             return False
  38         if p.type() == "longhand" and "IsLogical" in p.flags:
  39             return False
  40         return True
  41
  42     def getter_entry(p):
  43         if has_cpp_getter(p):
  44             return "DoGet" + p.method
  45         # Put a dummy getter here instead of nullptr because MSVC seems
  46         # to have bug which ruins the table when we put nullptr for
  47         # pointer-to-member-function. See bug 1471426.
  48         return "DummyGetter"
  49
  50     properties = runpy.run_path(dataFile)["data"]
  51
  52     entries = []
  53     indices = []
  54     asserts = []
  55     index_map = {}
  56     non_aliases = list(filter(lambda p: p.type() != "alias", properties.values()))
  57     for i, p in enumerate(sorted(non_aliases, key=order_key)):
  58         can_be_exposed = "true" if "ExposedOnGetCS" in p.flags else "false"
  59         entries.append(
  60             "{{ eCSSProperty_{}, {}, &nsComputedDOMStyle::{}}}".format(
  61                 p.id, can_be_exposed, getter_entry(p)
  62             )
  63         )
  64         index_map[p.id] = i
  65         i += 1
  66
  67     for i, p in enumerate(non_aliases):
  68         indices.append(str(index_map[p.id]))
  69         asserts.append(
  70             'static_assert(size_t(eCSSProperty_{}) == {}, "");'.format(p.id, i)
  71         )
  72
  73     assert len(indices) == len(entries)
  74
  75     output.write(
  76         FILE.format(
  77             indices=", ".join(indices),
  78             entries=",\n    ".join(entries),
  79             asserts="\n".join(asserts),
  80         )
  81     )