liberty/tools/lxdrgen-swift.awk

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2023-06-15 09:42:06 +02:00
# lxdrgen-swift.awk: Swift backend for lxdrgen.awk.
#
# Copyright (c) 2023, Přemysl Eric Janouch <p@janouch.name>
# SPDX-License-Identifier: 0BSD
function define_internal(name, swifttype) {
Types[name] = "internal"
CodegenSwiftType[name] = swifttype
CodegenDeserialize[name] = "%s.read()"
}
function define_sint(size, shortname, swifttype) {
shortname = "i" size
swifttype = "Int" size
define_internal(shortname, swifttype)
}
function define_uint(size, shortname, swifttype) {
shortname = "u" size
swifttype = "UInt" size
define_internal(shortname, swifttype)
}
function codegen_begin() {
define_sint("8")
define_sint("16")
define_sint("32")
define_sint("64")
define_uint("8")
define_uint("16")
define_uint("32")
define_uint("64")
define_internal("bool", "Bool")
define_internal("string", "String")
print "// Code generated from " FILENAME ". DO NOT EDIT."
print "import Foundation"
print ""
print "public struct RelayReader {"
print "\tpublic var data: Data"
print ""
print "\tpublic enum ReadError: Error {"
print "\t\tcase unexpectedEOF"
print "\t\tcase invalidEncoding"
print "\t\tcase overflow"
print "\t\tcase unexpectedValue"
print "\t}"
print ""
print "\tpublic mutating func read<T: FixedWidthInteger>() throws -> T {"
print "\t\tlet size = MemoryLayout<T>.size"
print "\t\tguard data.count >= size else {"
print "\t\t\tthrow ReadError.unexpectedEOF"
print "\t\t}"
print "\t\tvar acc: T = 0"
print "\t\tdata.prefix(size).forEach { acc = acc << 8 | T($0) }"
print "\t\tdata = data.dropFirst(size)"
print "\t\treturn acc"
print "\t}"
print ""
print "\tpublic mutating func read() throws -> Bool {"
print "\t\ttry read() != UInt8(0)"
print "\t}"
print ""
print "\tpublic mutating func read() throws -> String {"
print "\t\tlet size: UInt32 = try self.read()"
print "\t\tguard let count = Int(exactly: size) else {"
print "\t\t\tthrow ReadError.overflow"
print "\t\t}"
print "\t\tguard data.count >= count else {"
print "\t\t\tthrow ReadError.unexpectedEOF"
print "\t\t}"
print "\t\tdefer {"
print "\t\t\tdata = data.dropFirst(count)"
print "\t\t}"
print "\t\tif let s = String(data: data.prefix(count), encoding: .utf8) {"
print "\t\t\treturn s"
print "\t\t} else {"
print "\t\t\tthrow ReadError.invalidEncoding"
print "\t\t}"
print "\t}"
print ""
print "\tpublic mutating func read<" \
"T: RawRepresentable<Int8>>() throws -> T {"
print "\t\tguard let value = T(rawValue: try read()) else {"
print "\t\t\tthrow ReadError.unexpectedValue"
print "\t\t}"
print "\t\treturn value"
print "\t}"
print ""
print "\tpublic mutating func read<T>("
print "\t\t\t_ read: (inout Self) throws -> T) throws -> [T] {"
print "\t\tlet size: UInt32 = try self.read()"
print "\t\tguard let count = Int(exactly: size) else {"
print "\t\t\tthrow ReadError.overflow"
print "\t\t}"
print "\t\tvar array = [T]()"
print "\t\tarray.reserveCapacity(count)"
print "\t\tfor _ in 0..<count {"
print "\t\t\tarray.append(try read(&self))"
print "\t\t}"
print "\t\treturn array"
print "\t}"
print "}"
print ""
print "public struct RelayWriter {"
print "\tpublic var data = Data()"
print ""
print "\tpublic mutating func append<T: FixedWidthInteger>(_ number: T) {"
print "\t\tvar n = number.byteSwapped"
print "\t\tfor _ in 0..<MemoryLayout<T>.size {"
print "\t\t\tdata.append(UInt8(truncatingIfNeeded: n))"
print "\t\t\tn >>= 8"
print "\t\t}"
print "\t}"
print ""
print "\tpublic mutating func append(_ bool: Bool) {"
print "\t\tappend(UInt8(bool ? 1 : 0))"
print "\t}"
print ""
print "\tpublic mutating func append(_ string: String) {"
print "\t\tlet bytes = string.data(using: .utf8)!"
print "\t\tappend(UInt32(bytes.count))"
print "\t\tdata.append(bytes)"
print "\t}"
print ""
print "\tpublic mutating func append<" \
"T: RawRepresentable<Int8>>(_ value: T) {"
print "\t\tappend(value.rawValue)"
print "\t}"
print ""
print "\tpublic mutating func append<T>("
print "\t\t\t_ array: Array<T>, _ write: (inout Self, T) -> ()) {"
print "\t\tappend(UInt32(array.count))"
print "\t\tfor i in 0..<array.count {"
print "\t\t\twrite(&self, array[i])"
print "\t\t}"
print "\t}"
print ""
print "\tpublic mutating func append<T: RelayEncodable>(_ value: T) {"
print "\t\tvalue.encode(to: &self)"
print "\t}"
print "}"
print ""
print "public protocol RelayEncodable { " \
"func encode(to: inout RelayWriter) }"
}
function codegen_constant(name, value) {
print ""
print "public let " decapitalize(PrefixCamel snaketocamel(name)) " = " value
}
function codegen_enum_value(name, subname, value, cg) {
append(cg, "fields",
"\tcase " decapitalize(snaketocamel(subname)) " = " value "\n")
}
function codegen_enum(name, cg, swifttype) {
swifttype = PrefixCamel name
print ""
print "public enum " swifttype ": Int8 {"
print cg["fields"] "}"
CodegenSwiftType[name] = swifttype
CodegenDeserialize[name] = "%s.read()"
for (i in cg)
delete cg[i]
}
function codegen_struct_field(d, cg, camel) {
camel = decapitalize(snaketocamel(d["name"]))
if (!d["isarray"]) {
append(cg, "fields",
"\tpublic var " camel ": " CodegenSwiftType[d["type"]] "\n")
append(cg, "deserialize",
"\t\tself." camel " = try " \
sprintf(CodegenDeserialize[d["type"]], "from") "\n")
append(cg, "serialize",
"\t\tto.append(self." camel ")\n")
return
}
append(cg, "fields",
"\tpublic var " camel ": [" CodegenSwiftType[d["type"]] "]\n")
append(cg, "deserialize",
"\t\tself." camel " = try from.read() { r in try " \
sprintf(CodegenDeserialize[d["type"]], "r") " }\n")
append(cg, "serialize",
"\t\tto.append(self." camel ") { (w, value) in w.append(value) }\n")
}
function codegen_struct_tag(d, cg, camel) {
camel = decapitalize(snaketocamel(d["name"]))
append(cg, "serialize",
"\t\tto.append(self." camel ")\n")
}
function codegen_struct(name, cg, swifttype) {
swifttype = PrefixCamel name
print ""
print "public struct " swifttype " {\n" cg["fields"] "}"
print ""
print "extension " swifttype ": " PrefixCamel "Encodable {"
print "\tpublic init(from: inout RelayReader) throws {"
print cg["deserialize"] "\t}"
print ""
print "\tpublic func encode(to: inout RelayWriter) {"
print cg["serialize"] "\t}"
print "}"
CodegenSwiftType[name] = swifttype
CodegenDeserialize[name] = "%s.read()"
for (i in cg)
delete cg[i]
}
function codegen_union_tag(d, cg) {
cg["tagtype"] = d["type"]
cg["tagname"] = decapitalize(snaketocamel(d["name"]))
}
function codegen_union_struct(name, casename, cg, scg, swifttype) {
# And thus not all generated structs are present in Types.
swifttype = PrefixCamel name snaketocamel(casename)
casename = decapitalize(snaketocamel(casename))
print ""
print "public struct " swifttype ": " PrefixCamel name " {"
print "\tpublic var " cg["tagname"] \
": " CodegenSwiftType[cg["tagtype"]] " { ." casename " }"
print scg["fields"] "}"
print ""
print "extension " swifttype ": " PrefixCamel "Encodable {"
print "\tfileprivate init(from: inout RelayReader) throws {"
print scg["deserialize"] "\t}"
print ""
print "\tpublic func encode(to: inout RelayWriter) {"
print scg["serialize"] "\t}"
print "}"
append(cg, "cases", "\tcase ." casename ":\n" \
"\t\treturn try " swifttype "(from: &from)\n")
CodegenSwiftType[name] = swifttype
CodegenDeserialize[name] = "%s.read()"
for (i in scg)
delete scg[i]
}
function codegen_union(name, cg, swifttype, init) {
# Classes don't have automatic member-wise initializers,
# thus using structs and protocols.
swifttype = PrefixCamel name
print ""
print "public protocol " swifttype ": " PrefixCamel "Encodable {"
print "\tvar " cg["tagname"] ": " CodegenSwiftType[cg["tagtype"]] " { get }"
print "}"
init = decapitalize(swifttype)
print ""
print "public func " init \
"(from: inout RelayReader) throws -> " swifttype " {"
print "\tlet " cg["tagname"] ": " CodegenSwiftType[cg["tagtype"]] \
" = try from.read()"
print "\tswitch " cg["tagname"] " {"
# TODO: Only generate the default if there are remaining values,
# so that swiftc doesn't produce warnings.
print cg["cases"] "\tdefault:"
print "\t\tthrow RelayReader.ReadError.unexpectedValue"
print"\t}"
print "}"
CodegenSwiftType[name] = swifttype
CodegenDeserialize[name] = init "(from: &%s)"
for (i in cg)
delete cg[i]
}