зеркало из https://github.com/mozilla/gecko-dev.git
573 строки
18 KiB
Python
573 строки
18 KiB
Python
# rust.py - Generate rust bindings from IDL.
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, You can obtain one at http://mozilla.org/MPL/2.0/.
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"""Print a runtime Rust bindings file for the IDL file specified"""
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# --- Safety Hazards ---
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# We currently don't generate some bindings for some IDL methods in rust code,
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# due to there being ABI safety hazards if we were to do so. This is the
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# documentation for the reasons why we don't generate certain types of bindings,
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# so that we don't accidentally start generating them in the future.
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# notxpcom methods and attributes return their results directly by value. The x86
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# windows stdcall ABI returns aggregates by value differently for methods than
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# functions, and rust only exposes the function ABI, so that's the one we're
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# using. The correct ABI can be emulated for notxpcom methods returning aggregates
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# by passing an &mut ReturnType parameter as the second parameter. This strategy
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# is used by the winapi-rs crate.
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# https://github.com/retep998/winapi-rs/blob/7338a5216a6a7abeefcc6bb1bc34381c81d3e247/src/macros.rs#L220-L231
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#
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# Right now we can generate code for notxpcom methods and attributes, as we don't
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# support passing aggregates by value over these APIs ever (the types which are
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# allowed in xpidl.py shouldn't include any aggregates), so the code is
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# correct. In the future if we want to start supporting returning aggregates by
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# value, we will need to use a workaround such as the one used by winapi.rs.
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# nostdcall methods on x86 windows will use the thiscall ABI, which is not
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# stable in rust right now, so we cannot generate bindings to them.
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# In general, passing C++ objects by value over the C ABI is not a good idea,
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# and when possible we should avoid doing so. We don't generate bindings for
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# these methods here currently.
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import os.path
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import re
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import xpidl
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class AutoIndent(object):
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"""A small autoindenting wrapper around a fd.
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Used to make the code output more readable."""
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def __init__(self, fd):
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self.fd = fd
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self.indent = 0
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def write(self, string):
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"""A smart write function which automatically adjusts the
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indentation of each line as it is written by counting braces"""
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for s in string.split('\n'):
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s = s.strip()
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indent = self.indent
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if len(s) == 0:
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indent = 0
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elif s[0] == '}':
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indent -= 1
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self.fd.write(" " * indent + s + "\n")
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for c in s:
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if c == '(' or c == '{' or c == '[':
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self.indent += 1
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elif c == ')' or c == '}' or c == ']':
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self.indent -= 1
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def rustSanitize(s):
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keywords = [
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"abstract", "alignof", "as", "become", "box",
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"break", "const", "continue", "crate", "do",
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"else", "enum", "extern", "false", "final",
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"fn", "for", "if", "impl", "in",
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"let", "loop", "macro", "match", "mod",
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"move", "mut", "offsetof", "override", "priv",
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"proc", "pub", "pure", "ref", "return",
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"Self", "self", "sizeof", "static", "struct",
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"super", "trait", "true", "type", "typeof",
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"unsafe", "unsized", "use", "virtual", "where",
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"while", "yield"
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]
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if s in keywords:
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return s + "_"
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return s
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# printdoccomments = False
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printdoccomments = True
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if printdoccomments:
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def printComments(fd, clist, indent):
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fd.write("%s%s" % (indent, doccomments(clist)))
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def doccomments(clist):
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if len(clist) == 0:
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return ""
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s = "/// ```text"
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for c in clist:
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for cc in c.splitlines():
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s += "\n/// " + cc
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s += "\n/// ```\n///\n"
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return s
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else:
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def printComments(fd, clist, indent):
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pass
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def doccomments(clist):
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return ""
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def firstCap(str):
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return str[0].upper() + str[1:]
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# Attribute VTable Methods
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def attributeNativeName(a, getter):
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binaryname = rustSanitize(a.binaryname if a.binaryname else firstCap(a.name))
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return "%s%s" % ('Get' if getter else 'Set', binaryname)
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def attributeReturnType(a, getter):
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if a.notxpcom:
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if getter:
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return a.realtype.rustType('in').strip()
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return "::libc::c_void"
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return "::nserror::nsresult"
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def attributeParamName(a):
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return "a" + firstCap(a.name)
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def attributeRawParamList(iface, a, getter):
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if getter and a.notxpcom:
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l = []
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else:
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l = [(attributeParamName(a),
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a.realtype.rustType('out' if getter else 'in'))]
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if a.implicit_jscontext:
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raise xpidl.RustNoncompat("jscontext is unsupported")
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if a.nostdcall:
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raise xpidl.RustNoncompat("nostdcall is unsupported")
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return l
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def attributeParamList(iface, a, getter):
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l = ["this: *const " + iface.name]
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l += ["%s: %s" % x for x in attributeRawParamList(iface, a, getter)]
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return ", ".join(l)
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def attrAsVTableEntry(iface, m, getter):
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try:
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return "pub %s: unsafe extern \"system\" fn (%s) -> %s" % \
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(attributeNativeName(m, getter),
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attributeParamList(iface, m, getter),
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attributeReturnType(m, getter))
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except xpidl.RustNoncompat as reason:
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return """\
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/// Unable to generate binding because `%s`
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pub %s: *const ::libc::c_void""" % (reason, attributeNativeName(m, getter))
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# Method VTable generation functions
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def methodNativeName(m):
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binaryname = m.binaryname is not None and m.binaryname or firstCap(m.name)
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return rustSanitize(binaryname)
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def methodReturnType(m):
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if m.notxpcom:
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return m.realtype.rustType('in').strip()
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return "::nserror::nsresult"
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def methodRawParamList(iface, m):
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l = [(rustSanitize(p.name), p.rustType()) for p in m.params]
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if m.implicit_jscontext:
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raise xpidl.RustNoncompat("jscontext is unsupported")
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if m.optional_argc:
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raise xpidl.RustNoncompat("optional_argc is unsupported")
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if m.nostdcall:
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raise xpidl.RustNoncompat("nostdcall is unsupported")
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if not m.notxpcom and m.realtype.name != 'void':
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l.append(("_retval", m.realtype.rustType('out')))
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return l
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def methodParamList(iface, m):
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l = ["this: *const %s" % iface.name]
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l += ["%s: %s" % x for x in methodRawParamList(iface, m)]
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return ", ".join(l)
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def methodAsVTableEntry(iface, m):
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try:
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return "pub %s: unsafe extern \"system\" fn (%s) -> %s" % \
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(methodNativeName(m),
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methodParamList(iface, m),
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methodReturnType(m))
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except xpidl.RustNoncompat as reason:
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return """\
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/// Unable to generate binding because `%s`
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pub %s: *const ::libc::c_void""" % (reason, methodNativeName(m))
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method_impl_tmpl = """\
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#[inline]
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pub unsafe fn %(name)s(&self, %(params)s) -> %(ret_ty)s {
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((*self.vtable).%(name)s)(self, %(args)s)
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}
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"""
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def methodAsWrapper(iface, m):
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try:
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param_list = methodRawParamList(iface, m)
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params = ["%s: %s" % x for x in param_list]
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args = [x[0] for x in param_list]
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return method_impl_tmpl % {
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'name': methodNativeName(m),
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'params': ', '.join(params),
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'ret_ty': methodReturnType(m),
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'args': ', '.join(args),
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}
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except xpidl.RustNoncompat:
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# Dummy field for the doc comments to attach to.
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# Private so that it's not shown in rustdoc.
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return "const _%s: () = ();" % methodNativeName(m)
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infallible_impl_tmpl = """\
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#[inline]
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pub unsafe fn %(name)s(&self) -> %(realtype)s {
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let mut result = <%(realtype)s as ::std::default::Default>::default();
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let _rv = ((*self.vtable).%(name)s)(self, &mut result);
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debug_assert!(::nserror::NsresultExt::succeeded(_rv));
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result
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}
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"""
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def attrAsWrapper(iface, m, getter):
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try:
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if m.implicit_jscontext:
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raise xpidl.RustNoncompat("jscontext is unsupported")
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if m.nostdcall:
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raise xpidl.RustNoncompat("nostdcall is unsupported")
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name = attributeParamName(m)
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if getter and m.infallible and m.realtype.kind == 'builtin':
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# NOTE: We don't support non-builtin infallible getters in Rust code.
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return infallible_impl_tmpl % {
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'name': attributeNativeName(m, getter),
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'realtype': m.realtype.rustType('in'),
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}
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param_list = attributeRawParamList(iface, m, getter)
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params = ["%s: %s" % x for x in param_list]
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return method_impl_tmpl % {
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'name': attributeNativeName(m, getter),
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'params': ', '.join(params),
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'ret_ty': attributeReturnType(m, getter),
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'args': '' if getter and m.notxpcom else name,
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}
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except xpidl.RustNoncompat:
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# Dummy field for the doc comments to attach to.
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# Private so that it's not shown in rustdoc.
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return "const _%s: () = ();" % attributeNativeName(m, getter)
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header = """\
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//
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// DO NOT EDIT. THIS FILE IS GENERATED FROM %(filename)s
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//
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"""
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def idl_basename(f):
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"""returns the base name of a file with the last extension stripped"""
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return os.path.splitext(os.path.basename(f))[0]
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def print_rust_bindings(idl, fd, filename):
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fd = AutoIndent(fd)
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fd.write(header % {'filename': filename})
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# All of the idl files will be included into the same rust module, as we
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# can't do forward declarations. Because of this, we want to ignore all
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# import statements
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for p in idl.productions:
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if p.kind == 'include' or p.kind == 'cdata' or p.kind == 'forward':
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continue
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if p.kind == 'interface':
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write_interface(p, fd)
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continue
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if p.kind == 'typedef':
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try:
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# We have to skip the typedef of bool to bool (it doesn't make any sense anyways)
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if p.name == "bool":
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continue
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if printdoccomments:
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fd.write("/// `typedef %s %s;`\n///\n" %
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(p.realtype.nativeType('in'), p.name))
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fd.write(doccomments(p.doccomments))
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fd.write("pub type %s = %s;\n\n" % (p.name, p.realtype.rustType('in')))
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except xpidl.RustNoncompat as reason:
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fd.write("/* unable to generate %s typedef because `%s` */\n\n" %
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(p.name, reason))
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base_vtable_tmpl = """
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/// We need to include the members from the base interface's vtable at the start
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/// of the VTable definition.
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pub __base: %sVTable,
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"""
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vtable_tmpl = """\
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// This struct represents the interface's VTable. A pointer to a statically
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// allocated version of this struct is at the beginning of every %(name)s
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// object. It contains one pointer field for each method in the interface. In
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// the case where we can't generate a binding for a method, we include a void
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// pointer.
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#[doc(hidden)]
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#[repr(C)]
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pub struct %(name)sVTable {%(base)s%(entries)s}
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"""
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# NOTE: This template is not generated for nsISupports, as it has no base interfaces.
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deref_tmpl = """\
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// Every interface struct type implements `Deref` to its base interface. This
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// causes methods on the base interfaces to be directly avaliable on the
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// object. For example, you can call `.AddRef` or `.QueryInterface` directly
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// on any interface which inherits from `nsISupports`.
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impl ::std::ops::Deref for %(name)s {
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type Target = %(base)s;
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#[inline]
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fn deref(&self) -> &%(base)s {
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unsafe {
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::std::mem::transmute(self)
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}
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}
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}
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// Ensure we can use .coerce() to cast to our base types as well. Any type which
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// our base interface can coerce from should be coercable from us as well.
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impl<T: %(base)sCoerce> %(name)sCoerce for T {
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#[inline]
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fn coerce_from(v: &%(name)s) -> &Self {
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T::coerce_from(v)
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}
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}
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"""
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struct_tmpl = """\
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// The actual type definition for the interface. This struct has methods
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// declared on it which will call through its vtable. You never want to pass
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// this type around by value, always pass it behind a reference.
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#[repr(C)]
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pub struct %(name)s {
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vtable: *const %(name)sVTable,
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/// This field is a phantomdata to ensure that the VTable type and any
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/// struct containing it is not safe to send across threads, as XPCOM is
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/// generally not threadsafe.
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///
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/// XPCOM interfaces in general are not safe to send across threads.
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__nosync: ::std::marker::PhantomData<::std::rc::Rc<u8>>,
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}
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// Implementing XpCom for an interface exposes its IID, which allows for easy
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// use of the `.query_interface<T>` helper method. This also defines that
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// method for %(name)s.
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unsafe impl XpCom for %(name)s {
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const IID: nsIID = nsID(0x%(m0)s, 0x%(m1)s, 0x%(m2)s,
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[%(m3joined)s]);
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}
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// We need to implement the RefCounted trait so we can be used with `RefPtr`.
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// This trait teaches `RefPtr` how to manage our memory.
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unsafe impl RefCounted for %(name)s {
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#[inline]
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unsafe fn addref(&self) {
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self.AddRef();
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}
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#[inline]
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unsafe fn release(&self) {
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self.Release();
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}
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}
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// This trait is implemented on all types which can be coerced to from %(name)s.
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// It is used in the implementation of `fn coerce<T>`. We hide it from the
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// documentation, because it clutters it up a lot.
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#[doc(hidden)]
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pub trait %(name)sCoerce {
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/// Cheaply cast a value of this type from a `%(name)s`.
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fn coerce_from(v: &%(name)s) -> &Self;
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}
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// The trivial implementation: We can obviously coerce ourselves to ourselves.
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impl %(name)sCoerce for %(name)s {
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#[inline]
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fn coerce_from(v: &%(name)s) -> &Self {
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v
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}
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}
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impl %(name)s {
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/// Cast this `%(name)s` to one of its base interfaces.
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#[inline]
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pub fn coerce<T: %(name)sCoerce>(&self) -> &T {
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T::coerce_from(self)
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}
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}
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"""
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wrapper_tmpl = """\
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// The implementations of the function wrappers which are exposed to rust code.
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// Call these methods rather than manually calling through the VTable struct.
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impl %(name)s {
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%(consts)s
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%(methods)s
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}
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"""
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vtable_entry_tmpl = """\
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/* %(idl)s */
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%(entry)s,
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"""
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const_wrapper_tmpl = """\
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%(docs)s
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pub const %(name)s: i64 = %(val)s;
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"""
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method_wrapper_tmpl = """\
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%(docs)s
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/// `%(idl)s`
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%(wrapper)s
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"""
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uuid_decoder = re.compile(r"""(?P<m0>[a-f0-9]{8})-
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(?P<m1>[a-f0-9]{4})-
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(?P<m2>[a-f0-9]{4})-
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(?P<m3>[a-f0-9]{4})-
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(?P<m4>[a-f0-9]{12})$""", re.X)
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def write_interface(iface, fd):
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if iface.namemap is None:
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raise Exception("Interface was not resolved.")
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# if we see a base class-less type other than nsISupports, we just need
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# to discard anything else about it other than its constants.
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if iface.base is None and iface.name != "nsISupports":
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assert len([m for m in iface.members
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if type(m) == xpidl.Attribute or type(m) == xpidl.Method]) == 0
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return
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# Extract the UUID's information so that it can be written into the struct definition
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names = uuid_decoder.match(iface.attributes.uuid).groupdict()
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m3str = names['m3'] + names['m4']
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names['m3joined'] = ", ".join(["0x%s" % m3str[i:i+2] for i in xrange(0, 16, 2)])
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names['name'] = iface.name
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if printdoccomments:
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if iface.base is not None:
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fd.write("/// `interface %s : %s`\n///\n" %
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(iface.name, iface.base))
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else:
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fd.write("/// `interface %s`\n///\n" %
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iface.name)
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printComments(fd, iface.doccomments, '')
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fd.write(struct_tmpl % names)
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if iface.base is not None:
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fd.write(deref_tmpl % {
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'name': iface.name,
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|
'base': iface.base,
|
|
})
|
|
|
|
entries = []
|
|
for member in iface.members:
|
|
if type(member) == xpidl.Attribute:
|
|
entries.append(vtable_entry_tmpl % {
|
|
'idl': member.toIDL(),
|
|
'entry': attrAsVTableEntry(iface, member, True),
|
|
})
|
|
if not member.readonly:
|
|
entries.append(vtable_entry_tmpl % {
|
|
'idl': member.toIDL(),
|
|
'entry': attrAsVTableEntry(iface, member, False),
|
|
})
|
|
|
|
elif type(member) == xpidl.Method:
|
|
entries.append(vtable_entry_tmpl % {
|
|
'idl': member.toIDL(),
|
|
'entry': methodAsVTableEntry(iface, member),
|
|
})
|
|
|
|
fd.write(vtable_tmpl % {
|
|
'name': iface.name,
|
|
'base': base_vtable_tmpl % iface.base if iface.base is not None else "",
|
|
'entries': '\n'.join(entries),
|
|
})
|
|
|
|
# Get all of the constants
|
|
consts = []
|
|
for member in iface.members:
|
|
if type(member) == xpidl.ConstMember:
|
|
consts.append(const_wrapper_tmpl % {
|
|
'docs': doccomments(member.doccomments),
|
|
'name': member.name,
|
|
'val': member.getValue(),
|
|
})
|
|
|
|
methods = []
|
|
for member in iface.members:
|
|
if type(member) == xpidl.Attribute:
|
|
methods.append(method_wrapper_tmpl % {
|
|
'docs': doccomments(member.doccomments),
|
|
'idl': member.toIDL(),
|
|
'wrapper': attrAsWrapper(iface, member, True),
|
|
})
|
|
if not member.readonly:
|
|
methods.append(method_wrapper_tmpl % {
|
|
'docs': doccomments(member.doccomments),
|
|
'idl': member.toIDL(),
|
|
'wrapper': attrAsWrapper(iface, member, False),
|
|
})
|
|
|
|
elif type(member) == xpidl.Method:
|
|
methods.append(method_wrapper_tmpl % {
|
|
'docs': doccomments(member.doccomments),
|
|
'idl': member.toIDL(),
|
|
'wrapper': methodAsWrapper(iface, member),
|
|
})
|
|
|
|
fd.write(wrapper_tmpl % {
|
|
'name': iface.name,
|
|
'consts': '\n'.join(consts),
|
|
'methods': '\n'.join(methods),
|
|
})
|