The Tor Browser: comparison layout/style/generate-stylestructlist.py

--1:000000000000
+:90da9f660657
+#!/usr/bin/env python
+# 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/.
+# This script generates nsStyleStructList.h, which contains macro invocations
+# that can be used for three things:
+#
+# 1. To generate code for each inherited style struct.
+# 2. To generate code for each reset style struct.
+# 3. To generate a tree of nested if statements that can be used to run
+#    some code on each style struct.
+#
+# As an example, if we assume that we have only four style structs, the
+# generated tree of nested if statements looks like this:
+#
+#   if (STYLE_STRUCT_TEST < 4) {
+#     if (STYLE_STRUCT_TEST < 2) {
+#       if (STYLE_STRUCT_TEST == 0) {
+#         ... code for style struct with id 0 ...
+#       } else {
+#         ... code for style struct with id 1 ...
+#       }
+#     } else {
+#       if (STYLE_STRUCT_TEST == 2) {
+#         ... code for style struct with id 2 ...
+#       } else {
+#         ... code for style struct with id 3 ...
+#       }
+#     }
+#   }
+#
+# The TOPLEVELBRANCHES variable controls how widely we branch on the outermost
+# if statement.  In the example above, it splits the search space in 2, but with
+# a larger number of style structs to test -- particularly when the number is
+# closer to one power of two than the next higher one -- the average number of
+# comparisons can be reduced by splitting the top level check into more than 2.
+import math
+# List of style structs and their corresponding Check callback functions,
+# if any.
+STYLE_STRUCTS = [("INHERITED",) + x for x in [
+# Inherited style structs.
+("Font",           "CheckFontCallback"),
+("Color",          "CheckColorCallback"),
+("List",           "nullptr"),
+("Text",           "CheckTextCallback"),
+("Visibility",     "nullptr"),
+("Quotes",         "nullptr"),
+("UserInterface",  "nullptr"),
+("TableBorder",    "nullptr"),
+("SVG",            "nullptr"),
+("Variables",      "CheckVariablesCallback"),
+]] + [("RESET",) + x for x in [
+# Reset style structs.
+("Background",     "nullptr"),
+("Position",       "nullptr"),
+("TextReset",      "nullptr"),
+("Display",        "nullptr"),
+("Content",        "nullptr"),
+("UIReset",        "nullptr"),
+("Table",          "nullptr"),
+("Margin",         "nullptr"),
+("Padding",        "nullptr"),
+("Border",         "nullptr"),
+("Outline",        "nullptr"),
+("XUL",            "nullptr"),
+("SVGReset",       "nullptr"),
+("Column",         "nullptr"),
+]]
+# How widely to branch on the outermost if statement.
+TOPLEVELBRANCHES = 4
+# ---- Generate nsStyleStructList.h ----
+count = len(STYLE_STRUCTS)
+def nextPowerOf2(x):
+return int(pow(2, math.ceil(math.log(x, 2))))
+def printEntry(i):
+print "STYLE_STRUCT_%s(%s, %s)" % STYLE_STRUCTS[i]
+def printTestTree(min, max, depth, branches):
+indent = "  " * depth
+if min == count - 1 and max >= count:
+print "  STYLE_STRUCT_TEST_CODE(%sNS_ASSERTION(STYLE_STRUCT_TEST == %d, \"out of range\");)" % (indent, min)
+printEntry(min)
+elif max - min == 2:
+print "  STYLE_STRUCT_TEST_CODE(%sif (STYLE_STRUCT_TEST == %d) {)" % (indent, min)
+printEntry(min)
+print "  STYLE_STRUCT_TEST_CODE(%s} else {)" % indent
+printEntry(min + 1)
+print "  STYLE_STRUCT_TEST_CODE(%s})" % indent
+elif min < count:
+mid = min + (max - min) / branches
+print "  STYLE_STRUCT_TEST_CODE(%sif (STYLE_STRUCT_TEST < %d) {)" % (indent, mid)
+printTestTree(min, mid, depth + 1, 2)
+for branch in range(1, branches):
+lo = min + branch * (max - min) / branches
+hi = min + (branch + 1) * (max - min) / branches
+if lo >= count:
+break
+if branch == branches - 1 or hi >= count:
+print "  STYLE_STRUCT_TEST_CODE(%s} else {)" % indent
+else:
+print "  STYLE_STRUCT_TEST_CODE(%s} else if (STYLE_STRUCT_TEST < %d) {)" % (indent, hi)
+printTestTree(lo, hi, depth + 1, 2)
+print "  STYLE_STRUCT_TEST_CODE(%s})" % indent
+HEADER = """/* THIS FILE IS AUTOGENERATED BY generate-stylestructlist.py - DO NOT EDIT */
+// IWYU pragma: private, include "nsStyleStructFwd.h"
+/*
+* list of structs that contain the data provided by nsStyleContext, the
+* internal API for computed style data for an element
+*/
+/*
+* This file is intended to be used by different parts of the code, with
+* the STYLE_STRUCT macro (or the STYLE_STRUCT_INHERITED and
+* STYLE_STRUCT_RESET pair of macros) defined in different ways.
+*/
+#ifndef STYLE_STRUCT_INHERITED
+#define STYLE_STRUCT_INHERITED(name, checkdata_cb) \\
+STYLE_STRUCT(name, checkdata_cb)
+#define UNDEF_STYLE_STRUCT_INHERITED
+#endif
+#ifndef STYLE_STRUCT_RESET
+#define STYLE_STRUCT_RESET(name, checkdata_cb) \\
+STYLE_STRUCT(name, checkdata_cb)
+#define UNDEF_STYLE_STRUCT_RESET
+#endif
+#ifdef STYLE_STRUCT_TEST
+#define STYLE_STRUCT_TEST_CODE(c) c
+#else
+#define STYLE_STRUCT_TEST_CODE(c)
+#endif
+// The inherited structs are listed before the Reset structs.
+// nsStyleStructID assumes this is the case, and callers other than
+// nsStyleStructFwd.h that want the structs in id-order just define
+// STYLE_STRUCT rather than including the file twice.
+"""
+FOOTER = """
+#ifdef UNDEF_STYLE_STRUCT_INHERITED
+#undef STYLE_STRUCT_INHERITED
+#undef UNDEF_STYLE_STRUCT_INHERITED
+#endif
+#ifdef UNDEF_STYLE_STRUCT_RESET
+#undef STYLE_STRUCT_RESET
+#undef UNDEF_STYLE_STRUCT_RESET
+#endif
+#undef STYLE_STRUCT_TEST_CODE
+"""
+print HEADER
+printTestTree(0, nextPowerOf2(count), 0, TOPLEVELBRANCHES)
+print FOOTER

The Tor Browser / file comparison

comparison: layout/style/generate-stylestructlist.py

layout/style/generate-stylestructlist.py