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68154b269c
We currently generate absolute paths in all of our XPIDL-generated source files, which is not so great for several reasons (deterministic generation of files across machines, Searchfox analysis logic, shared compilation caches, etc.). Let's generate paths that still indicate where you should be looking, but are identical across compilations, objdirs, etc. Differential Revision: https://phabricator.services.mozilla.com/D73747
570 lines
18 KiB
Python
570 lines
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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from __future__ import absolute_import
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import os.path
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import re
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from xpidl 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!(_rv.succeeded());
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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 $SRCDIR/%(relpath)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, relpath):
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fd = AutoIndent(fd)
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fd.write(header % {'relpath': relpath})
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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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assert iface.base or (iface.name == "nsISupports")
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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 range(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 % {
|
|
'name': iface.name,
|
|
'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),
|
|
})
|