liberty/tools/lxdrgen-go.awk

541 lines
15 KiB
Awk

# lxdrgen-go.awk: Go backend for lxdrgen.awk.
#
# Copyright (c) 2022, Přemysl Eric Janouch <p@janouch.name>
# SPDX-License-Identifier: 0BSD
#
# This backend also enables proxying to other endpoints using JSON.
function define_internal(name, gotype) {
Types[name] = "internal"
CodegenGoType[name] = gotype
}
function define_sint(size, shortname, gotype) {
shortname = "i" size
gotype = "int" size
define_internal(shortname, gotype)
CodegenAppendJSON[shortname] = \
"\tb = strconv.AppendInt(b, int64(%s), 10)\n"
if (size == 8) {
CodegenSerialize[shortname] = "\tdata = append(data, uint8(%s))\n"
CodegenDeserialize[shortname] = \
"\tif len(data) >= 1 {\n" \
"\t\t%s, data = int8(data[0]), data[1:]\n" \
"\t} else {\n" \
"\t\treturn nil, false\n" \
"\t}\n"
return
}
CodegenSerialize[shortname] = \
"\tdata = binary.BigEndian.AppendUint" size "(data, uint" size "(%s))\n"
CodegenDeserialize[shortname] = \
"\tif len(data) >= " (size / 8) " {\n" \
"\t\t%s = " gotype "(binary.BigEndian.Uint" size "(data))\n" \
"\t\tdata = data[" (size / 8) ":]\n" \
"\t} else {\n" \
"\t\treturn nil, false\n" \
"\t}\n"
}
function define_uint(size, shortname, gotype) {
# Both []byte and []uint8 luckily marshal as base64-encoded JSON strings,
# so there's no need to rename the type as an exception.
shortname = "u" size
gotype = "uint" size
define_internal(shortname, gotype)
CodegenAppendJSON[shortname] = \
"\tb = strconv.AppendUint(b, uint64(%s), 10)\n"
if (size == 8) {
CodegenSerialize[shortname] = "\tdata = append(data, %s)\n"
CodegenDeserialize[shortname] = \
"\tif len(data) >= 1 {\n" \
"\t\t%s, data = data[0], data[1:]\n" \
"\t} else {\n" \
"\t\treturn nil, false\n" \
"\t}\n"
return
}
CodegenSerialize[shortname] = \
"\tdata = binary.BigEndian.AppendUint" size "(data, %s)\n"
CodegenDeserialize[shortname] = \
"\tif len(data) >= " (size / 8) " {\n" \
"\t\t%s = binary.BigEndian.Uint" size "(data)\n" \
"\t\tdata = data[" (size / 8) ":]\n" \
"\t} else {\n" \
"\t\treturn nil, false\n" \
"\t}\n"
}
# Currently two outputs cannot coexist within the same package.
function codegen_private(name) {
return "proto" name
}
function codegen_begin( funcname) {
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")
# Cater to "go generate", for what it's worth.
CodegenPackage = ENV["GOPACKAGE"]
if (!CodegenPackage)
CodegenPackage = "main"
print "// Code generated from " FILENAME ". DO NOT EDIT."
print ""
print "package " CodegenPackage
print ""
print "import ("
print "\t`encoding/base64`"
print "\t`encoding/binary`"
print "\t`encoding/json`"
print "\t`errors`"
print "\t`math`"
print "\t`strconv`"
print "\t`unicode/utf8`"
print ")"
print ""
print "// This is a hack to always use the base64 import."
print "var _ = base64.StdEncoding"
print ""
CodegenAppendJSON["bool"] = \
"\tb = strconv.AppendBool(b, %s)\n"
CodegenSerialize["bool"] = \
"\tif %s {\n" \
"\t\tdata = append(data, 1)\n" \
"\t} else {\n" \
"\t\tdata = append(data, 0)\n" \
"\t}\n"
funcname = codegen_private("ConsumeBoolFrom")
print "// " funcname " tries to deserialize a boolean value"
print "// from the beginning of a byte stream. When successful,"
print "// it returns a subslice with any data that might follow."
print "func " funcname "(data []byte, b *bool) ([]byte, bool) {"
print "\tif len(data) < 1 {"
print "\t\treturn nil, false"
print "\t}"
print "\tif data[0] != 0 {"
print "\t\t*b = true"
print "\t} else {"
print "\t\t*b = false"
print "\t}"
print "\treturn data[1:], true"
print "}"
print ""
CodegenDeserialize["bool"] = \
"\tif data, ok = " funcname "(data, &%s); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
funcname = codegen_private("AppendStringTo")
print "// " funcname " tries to serialize a string value,"
print "// appending it to the end of a byte stream."
print "func " funcname "(data []byte, s string) ([]byte, bool) {"
print "\tif len(s) > math.MaxUint32 {"
print "\t\treturn nil, false"
print "\t}"
print "\tdata = binary.BigEndian.AppendUint32(data, uint32(len(s)))"
print "\treturn append(data, s...), true"
print "}"
print ""
CodegenSerialize["string"] = \
"\tif data, ok = " funcname "(data, %s); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
funcname = codegen_private("ConsumeStringFrom")
print "// " funcname " tries to deserialize a string value"
print "// from the beginning of a byte stream. When successful,"
print "// it returns a subslice with any data that might follow."
print "func " funcname "(data []byte, s *string) ([]byte, bool) {"
print "\tif len(data) < 4 {"
print "\t\treturn nil, false"
print "\t}"
print "\tlength := binary.BigEndian.Uint32(data)"
print "\tif data = data[4:]; uint64(len(data)) < uint64(length) {"
print "\t\treturn nil, false"
print "\t}"
print "\t*s = string(data[:length])"
print "\tif !utf8.ValidString(*s) {"
print "\t\treturn nil, false"
print "\t}"
print "\treturn data[length:], true"
print "}"
print ""
CodegenDeserialize["string"] = \
"\tif data, ok = " funcname "(data, &%s); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
funcname = codegen_private("UnmarshalEnumJSON")
print "// " funcname " converts a JSON fragment to an integer,"
print "// ensuring that it's within the expected range of enum values."
print "func " funcname "(data []byte) (int64, error) {"
print "\tvar n int64"
print "\tif err := json.Unmarshal(data, &n); err != nil {"
print "\t\treturn 0, err"
print "\t} else if n > math.MaxInt8 || n < math.MinInt8 {"
print "\t\treturn 0, errors.New(`integer out of range`)"
print "\t} else {"
print "\t\treturn n, nil"
print "\t}"
print "}"
print ""
}
function codegen_constant(name, value) {
print "const " PrefixCamel snaketocamel(name) " = " value
print ""
}
function codegen_enum_value(name, subname, value, cg, goname) {
goname = PrefixCamel name snaketocamel(subname)
append(cg, "fields",
"\t" goname " = " value "\n")
append(cg, "stringer",
"\tcase " goname ":\n" \
"\t\treturn `" snaketocamel(subname) "`\n")
append(cg, "marshal",
goname ",\n")
append(cg, "unmarshal",
"\tcase `" snaketocamel(subname) "`:\n" \
"\t\t*v = " goname "\n")
}
function codegen_enum(name, cg, gotype, fields, funcname) {
gotype = PrefixCamel name
print "type " gotype " int8"
print ""
print "const ("
print cg["fields"] ")"
print ""
print "func (v " gotype ") String() string {"
print "\tswitch v {"
print cg["stringer"] "\tdefault:"
print "\t\treturn strconv.Itoa(int(v))"
print "\t}"
print "}"
print ""
CodegenIsMarshaler[name] = 1
fields = cg["marshal"]
sub(/,\n$/, ":", fields)
gsub(/\n/, "\n\t", fields)
print "func (v " gotype ") MarshalJSON() ([]byte, error) {"
print "\tswitch v {"
print indent("case " fields)
print "\t\treturn []byte(`\"` + v.String() + `\"`), nil"
print "\t}"
print "\treturn json.Marshal(int(v))"
print "}"
print ""
funcname = codegen_private("UnmarshalEnumJSON")
print "func (v *" gotype ") UnmarshalJSON(data []byte) error {"
print "\tvar s string"
print "\tif json.Unmarshal(data, &s) == nil {"
print "\t\t// Handled below."
print "\t} else if n, err := " funcname "(data); err != nil {"
print "\t\treturn err"
print "\t} else {"
print "\t\t*v = " gotype "(n)"
print "\t\treturn nil"
print "\t}"
print ""
print "\tswitch s {"
print cg["unmarshal"] "\tdefault:"
print "\t\treturn errors.New(`unrecognized value: ` + s)"
print "\t}"
print "\treturn nil"
print "}"
print ""
# XXX: This should also check if it isn't out-of-range for any reason,
# but our usage of sprintf() stands in the way a bit.
CodegenSerialize[name] = "\tdata = append(data, uint8(%s))\n"
CodegenDeserialize[name] = \
"\tif len(data) >= 1 {\n" \
"\t\t%s, data = " gotype "(data[0]), data[1:]\n" \
"\t} else {\n" \
"\t\treturn nil, false\n" \
"\t}\n"
CodegenGoType[name] = gotype
for (i in cg)
delete cg[i]
}
function codegen_marshal(type, f, marshal) {
if (CodegenAppendJSON[type])
return sprintf(CodegenAppendJSON[type], f)
# Complex types are json.Marshalers, there's no need to json.Marshal(&f).
if (CodegenIsMarshaler[type])
marshal = f ".MarshalJSON()"
else
marshal = "json.Marshal(" f ")"
return \
"\tif j, err := " marshal "; err != nil {\n" \
"\t\treturn nil, err\n" \
"\t} else {\n" \
"\t\tb = append(b, j...)\n" \
"\t}\n"
}
function codegen_struct_field_marshal(d, cg, camel, f, marshal) {
camel = snaketocamel(d["name"])
f = "s." camel
if (!d["isarray"]) {
append(cg, "marshal",
"\tb = append(b, `,\"" decapitalize(camel) "\":`...)\n" \
codegen_marshal(d["type"], f))
return
}
# Note that we do not produce `null` for nil slices, unlike encoding/json.
# And arrays never get deserialized as such.
if (d["type"] == "u8") {
append(cg, "marshal",
"\tb = append(b, `,\"" decapitalize(camel) "\":\"`...)\n" \
"\tb = append(b, base64.StdEncoding.EncodeToString(" f ")...)\n" \
"\tb = append(b, '\"')\n")
return
}
append(cg, "marshal",
"\tb = append(b, `,\"" decapitalize(camel) "\":[`...)\n" \
"\tfor i := 0; i < len(" f "); i++ {\n" \
"\t\tif i > 0 {\n" \
"\t\t\tb = append(b, ',')\n" \
"\t\t}\n" \
indent(codegen_marshal(d["type"], f "[i]")) \
"\t}\n" \
"\tb = append(b, ']')\n")
}
function codegen_struct_field(d, cg, camel, f, serialize, deserialize) {
codegen_struct_field_marshal(d, cg)
camel = snaketocamel(d["name"])
f = "s." camel
serialize = CodegenSerialize[d["type"]]
deserialize = CodegenDeserialize[d["type"]]
if (!d["isarray"]) {
append(cg, "fields", "\t" camel " " CodegenGoType[d["type"]] \
" `json:\"" decapitalize(camel) "\"`\n")
append(cg, "serialize", sprintf(serialize, f))
append(cg, "deserialize", sprintf(deserialize, f))
return
}
append(cg, "fields", "\t" camel " []" CodegenGoType[d["type"]] \
" `json:\"" decapitalize(camel) "\"`\n")
# XXX: This should also check if it isn't out-of-range for any reason.
append(cg, "serialize",
sprintf(CodegenSerialize["u32"], "uint32(len(" f "))"))
if (d["type"] == "u8") {
append(cg, "serialize",
"\tdata = append(data, " f "...)\n")
} else {
append(cg, "serialize",
"\tfor i := 0; i < len(" f "); i++ {\n" \
indent(sprintf(serialize, f "[i]")) \
"\t}\n")
}
append(cg, "deserialize",
"\t{\n" \
"\t\tvar length uint32\n" \
indent(sprintf(CodegenDeserialize["u32"], "length")))
if (d["type"] == "u8") {
append(cg, "deserialize",
"\t\tif uint64(len(data)) < uint64(length) {\n" \
"\t\t\treturn nil, false\n" \
"\t\t}\n" \
"\t\t" f ", data = data[:length], data[length:]\n" \
"\t}\n")
} else {
append(cg, "deserialize",
"\t\t" f " = make([]" CodegenGoType[d["type"]] ", length)\n" \
"\t}\n" \
"\tfor i := 0; i < len(" f "); i++ {\n" \
indent(sprintf(deserialize, f "[i]")) \
"\t}\n")
}
}
function codegen_struct_tag(d, cg, camel, f) {
codegen_struct_field_marshal(d, cg)
camel = snaketocamel(d["name"])
f = "s." camel
append(cg, "fields", "\t" camel " " CodegenGoType[d["type"]] \
" `json:\"" decapitalize(camel) "\"`\n")
append(cg, "serialize", sprintf(CodegenSerialize[d["type"]], f))
# Do not deserialize here, that is already done by the containing union.
}
function codegen_struct(name, cg, gotype) {
gotype = PrefixCamel name
print "type " gotype " struct {\n" cg["fields"] "}\n"
if (cg["marshal"]) {
CodegenIsMarshaler[name] = 1
print "func (s *" gotype ") MarshalJSON() ([]byte, error) {"
print "\tb := []byte{}"
print cg["marshal"] "\tb[0] = '{'"
print "\treturn append(b, '}'), nil"
print "}"
print ""
}
if (cg["serialize"]) {
print "func (s *" gotype ") AppendTo(data []byte) ([]byte, bool) {"
print "\tok := true"
print cg["serialize"] "\treturn data, ok"
print "}"
print ""
CodegenSerialize[name] = \
"\tif data, ok = %s.AppendTo(data); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
}
if (cg["deserialize"]) {
print "func (s *" gotype ") ConsumeFrom(data []byte) ([]byte, bool) {"
print "\tok := true"
print cg["deserialize"] "\treturn data, ok"
print "}"
print ""
CodegenDeserialize[name] = \
"\tif data, ok = %s.ConsumeFrom(data); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
}
CodegenGoType[name] = gotype
for (i in cg)
delete cg[i]
}
function codegen_union_tag(d, cg) {
cg["tagtype"] = d["type"]
cg["tagname"] = snaketocamel(d["name"])
# The tag is implied from the type of struct stored in the interface.
}
function codegen_union_struct(name, casename, cg, scg, structname, init) {
# And thus not all generated structs are present in Types.
structname = name snaketocamel(casename)
codegen_struct(structname, scg)
init = CodegenGoType[structname] "{" cg["tagname"] \
": " decapitalize(cg["tagname"]) "}"
append(cg, "unmarshal",
"\tcase " CodegenGoType[cg["tagtype"]] snaketocamel(casename) ":\n" \
"\t\ts := " init "\n" \
"\t\terr = json.Unmarshal(data, &s)\n" \
"\t\tu.Interface = &s\n")
append(cg, "serialize",
"\tcase *" CodegenGoType[structname] ":\n" \
indent(sprintf(CodegenSerialize[structname], "union")))
append(cg, "deserialize",
"\tcase " CodegenGoType[cg["tagtype"]] snaketocamel(casename) ":\n" \
"\t\ts := " init "\n" \
indent(sprintf(CodegenDeserialize[structname], "s")) \
"\t\tu.Interface = &s\n")
}
function codegen_union(name, cg, gotype, tagvar) {
gotype = PrefixCamel name
print "type " gotype " struct {"
print "\tInterface any"
print "}"
print ""
# This cannot be a pointer method, it wouldn't work recursively.
CodegenIsMarshaler[name] = 1
print "func (u " gotype ") MarshalJSON() ([]byte, error) {"
print "\treturn u.Interface.(json.Marshaler).MarshalJSON()"
print "}"
print ""
tagvar = decapitalize(cg["tagname"])
print "func (u *" gotype ") UnmarshalJSON(data []byte) (err error) {"
print "\tvar t struct {"
print "\t\t" cg["tagname"] " " CodegenGoType[cg["tagtype"]] \
" `json:\"" tagvar "\"`"
print "\t}"
print "\tif err := json.Unmarshal(data, &t); err != nil {"
print "\t\treturn err"
print "\t}"
print ""
print "\tswitch " tagvar " := t." cg["tagname"] "; " tagvar " {"
print cg["unmarshal"] "\tdefault:"
print "\t\terr = errors.New(`unsupported value: ` + " tagvar ".String())"
print "\t}"
print "\treturn err"
print "}"
print ""
# XXX: Consider changing the interface into an AppendTo/ConsumeFrom one,
# that would eliminate these type case switches entirely.
# On the other hand, it would make it possible to send unsuitable structs.
print "func (u *" gotype ") AppendTo(data []byte) ([]byte, bool) {"
print "\tok := true"
print "\tswitch union := u.Interface.(type) {"
print cg["serialize"] "\tdefault:"
print "\t\treturn nil, false"
print "\t}"
print "\treturn data, ok"
print "}"
print ""
CodegenSerialize[name] = \
"\tif data, ok = %s.AppendTo(data); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
print "func (u *" gotype ") ConsumeFrom(data []byte) ([]byte, bool) {"
print "\tok := true"
print "\tvar " tagvar " " CodegenGoType[cg["tagtype"]]
print sprintf(CodegenDeserialize[cg["tagtype"]], tagvar)
print "\tswitch " tagvar " {"
print cg["deserialize"] "\tdefault:"
print "\t\treturn nil, false"
print "\t}"
print "\treturn data, ok"
print "}"
print ""
CodegenDeserialize[name] = \
"\tif data, ok = %s.ConsumeFrom(data); !ok {\n" \
"\t\treturn nil, ok\n" \
"\t}\n"
CodegenGoType[name] = gotype
for (i in cg)
delete cg[i]
}