servo/ports/geckolib/binding_tools/regen_atoms.py

#!/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/.

import re
import os


def gnu_symbolify(source, ident):
    return "_ZN" + str(len(source.CLASS)) + source.CLASS + str(len(ident)) + ident + "E"


def msvc64_symbolify(source, ident):
    return "?" + ident + "@" + source.CLASS + "@@2PEAV" + source.TYPE + "@@EA"


def msvc32_symbolify(source, ident):
    # Prepend "\x01" to avoid LLVM prefixing the mangled name with "_".
    # See https://github.com/rust-lang/rust/issues/36097
    return "\\x01?" + ident + "@" + source.CLASS + "@@2PAV" + source.TYPE + "@@A"


class GkAtomSource:
    PATTERN = re.compile('^GK_ATOM\((.+),\s*"(.*)"\)')
    FILE = "dist/include/nsGkAtomList.h"
    CLASS = "nsGkAtoms"
    TYPE = "nsIAtom"


class CSSPseudoElementsAtomSource:
    PATTERN = re.compile('^CSS_PSEUDO_ELEMENT\((.+),\s*"(.*)",')
    FILE = "dist/include/nsCSSPseudoElementList.h"
    CLASS = "nsCSSPseudoElements"
    # NB: nsICSSPseudoElement is effectively the same as a nsIAtom, but we need
    # this for MSVC name mangling.
    TYPE = "nsICSSPseudoElement"


class CSSAnonBoxesAtomSource:
    PATTERN = re.compile('^CSS_ANON_BOX\((.+),\s*"(.*)"\)')
    FILE = "dist/include/nsCSSAnonBoxList.h"
    CLASS = "nsCSSAnonBoxes"
    TYPE = "nsICSSAnonBoxPseudo"


SOURCES = [
    GkAtomSource,
    CSSPseudoElementsAtomSource,
    CSSAnonBoxesAtomSource,
]


def map_atom(ident):
    if ident in {"box", "loop", "match", "mod", "ref",
                 "self", "type", "use", "where", "in"}:
        return ident + "_"
    return ident


class Atom:
    def __init__(self, source, ident, value):
        self.ident = "{}_{}".format(source.CLASS, ident)
        self._original_ident = ident
        self.value = value
        self.source = source

    def cpp_class(self):
        return self.source.CLASS

    def gnu_symbol(self):
        return gnu_symbolify(self.source, self._original_ident)

    def msvc32_symbol(self):
        return msvc32_symbolify(self.source, self._original_ident)

    def msvc64_symbol(self):
        return msvc64_symbolify(self.source, self._original_ident)

    def type(self):
        return self.source.TYPE


def collect_atoms(objdir):
    atoms = []
    for source in SOURCES:
        with open(os.path.join(objdir, source.FILE)) as f:
            for line in f.readlines():
                result = re.match(source.PATTERN, line)
                if result:
                    atoms.append(Atom(source, result.group(1), result.group(2)))
    return atoms

PRELUDE = """
/* 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/. */

/* Autogenerated file, DO NOT EDIT DIRECTLY */
"""[1:]


def write_atom_macro(atoms, file_name):
    ATOM_TEMPLATE = """
            #[link_name = "{link_name}"]
            pub static {name}: *mut {type};
"""[1:]

    def write_items(f, func):
        f.write("        extern {\n")
        for atom in atoms:
            f.write(ATOM_TEMPLATE.format(name=atom.ident,
                                         link_name=func(atom),
                                         type=atom.type()))
        f.write("        }\n")

    with open(file_name, "wb") as f:
        f.write(PRELUDE)
        f.write("use gecko_bindings::structs::nsIAtom;\n\n")
        f.write("use Atom;\n\n")
        for source in SOURCES:
            if source.TYPE != "nsIAtom":
                f.write("pub enum {} {{}}\n\n".format(source.TYPE))
        f.write("""
            #[inline(always)] pub fn unsafe_atom_from_static(ptr: *mut nsIAtom) -> Atom {
                unsafe { Atom::from_static(ptr) }
            }\n\n
            """)
        f.write("cfg_if! {\n")
        f.write("    if #[cfg(not(target_env = \"msvc\"))] {\n")
        write_items(f, Atom.gnu_symbol)
        f.write("    } else if #[cfg(target_pointer_width = \"64\")] {\n")
        write_items(f, Atom.msvc64_symbol)
        f.write("    } else {\n")
        write_items(f, Atom.msvc32_symbol)
        f.write("    }\n")
        f.write("}\n\n")
        f.write("#[macro_export]\n")
        f.write("macro_rules! atom {\n")
        f.writelines(['("%s") => { $crate::atom_macro::unsafe_atom_from_static($crate::atom_macro::%s as *mut _) };\n'
                     % (atom.value, atom.ident) for atom in atoms])
        f.write("}\n")


PSEUDO_ELEMENT_HEADER = """
/*
 * This file contains a helper macro invocation to aid Gecko's style system
 * pseudo-element integration.
 *
 * This file is NOT INTENDED to be compiled as a standalone module.
 *
 * Also, it guarantees the property that normal pseudo-elements are processed
 * before anonymous boxes.
 *
 * Expected usage is as follows:
 *
 * ```
 * fn have_to_use_pseudo_elements() {
 *     macro_rules pseudo_element! {
 *         ($pseudo_str_with_colon:expr, $pseudo_atom:expr, $is_anon_box:true) => {{
 *             // Stuff stuff stuff.
 *         }}
 *     }
 *     include!("path/to/helper.rs")
 * }
 * ```
 *
 */
"""

PSEUDO_ELEMENT_MACRO_INVOCATION = """
    pseudo_element!(\"{}\",
                    atom!(\"{}\"),
                    {});
"""[1:]


def write_pseudo_element_helper(atoms, target_filename):
    with open(target_filename, "wb") as f:
        f.write(PRELUDE)
        f.write(PSEUDO_ELEMENT_HEADER)
        f.write("{\n")
        for atom in atoms:
            if atom.type() == "nsICSSPseudoElement":
                f.write(PSEUDO_ELEMENT_MACRO_INVOCATION.format(atom.value, atom.value, "false"))
            elif atom.type() == "nsICSSAnonBoxPseudo":
                f.write(PSEUDO_ELEMENT_MACRO_INVOCATION.format(atom.value, atom.value, "true"))
        f.write("}\n")


def build(objdir, verbose=False):
    atoms = collect_atoms(objdir)
    write_atom_macro(atoms, "../string_cache/atom_macro.rs")
    write_pseudo_element_helper(atoms, "../../../components/style/generated/gecko_pseudo_element_helper.rs")
    return 0