Merge 2c9c8ea83388495f96efe4a0831d582e03e03e6f into ba4ad521151d3500de111a037937f8e1dd3922d2

commit: d978b07b2a8b0f87e35e894cdd012bcfe768db25
author: ermite · 17h ago · 2026-10-22 06:13 UTC
merge of: ba4ad52 + 2c9c8ea · diff against the first parent
signature: unsigned

3 files · +397 -1

M cmd/xtgen/main.go +31 -1

@@ -1,4 +1,34 @@
1	1		// Command xtgen generates bindings from the pinned xcb-proto XML.
2	2		package main
3	3
4		-	func main() {}
	4	+	import (
	5	+	"flag"
	6	+	"fmt"
	7	+	"os"
	8	+	"path/filepath"
	9	+	)
	10	+
	11	+	func main() {
	12	+	all := flag.Bool("all", false, "process all vendored modules")
	13	+	flag.Parse()
	14	+	paths := flag.Args()
	15	+	if *all {
	16	+	var err error
	17	+	paths, err = filepath.Glob("spec/xml/*.xml")
	18	+	if err != nil {
	19	+	fmt.Fprintln(os.Stderr, err)
	20	+	os.Exit(1)
	21	+	}
	22	+	}
	23	+	if len(paths) == 0 {
	24	+	fmt.Fprintln(os.Stderr, "xtgen: supply XML paths or -all")
	25	+	os.Exit(1)
	26	+	}
	27	+	// T2.1 validates and builds the AST. Resolution and emission follow in T2.2.
	28	+	for _, path := range paths {
	29	+	if _, err := parseFile(path); err != nil {
	30	+	fmt.Fprintln(os.Stderr, err)
	31	+	os.Exit(1)
	32	+	}
	33	+	}
	34	+	}

@@ -1,4 +1,34 @@
1		// Command xtgen generates bindings from the pinned xcb-proto XML.	1		// Command xtgen generates bindings from the pinned xcb-proto XML.
2		package main	2		package main
3			3
4	-	func main() {}	4	+	import (
			5	+	"flag"
			6	+	"fmt"
			7	+	"os"
			8	+	"path/filepath"
			9	+	)
			10	+
			11	+	func main() {
			12	+	all := flag.Bool("all", false, "process all vendored modules")
			13	+	flag.Parse()
			14	+	paths := flag.Args()
			15	+	if *all {
			16	+	var err error
			17	+	paths, err = filepath.Glob("spec/xml/*.xml")
			18	+	if err != nil {
			19	+	fmt.Fprintln(os.Stderr, err)
			20	+	os.Exit(1)
			21	+	}
			22	+	}
			23	+	if len(paths) == 0 {
			24	+	fmt.Fprintln(os.Stderr, "xtgen: supply XML paths or -all")
			25	+	os.Exit(1)
			26	+	}
			27	+	// T2.1 validates and builds the AST. Resolution and emission follow in T2.2.
			28	+	for _, path := range paths {
			29	+	if _, err := parseFile(path); err != nil {
			30	+	fmt.Fprintln(os.Stderr, err)
			31	+	os.Exit(1)
			32	+	}
			33	+	}
			34	+	}

A cmd/xtgen/parse.go +292 -0

@@ -0,0 +1,292 @@
	1	+	package main
	2	+
	3	+	import (
	4	+	"encoding/xml"
	5	+	"fmt"
	6	+	"io"
	7	+	"os"
	8	+	"strconv"
	9	+	"strings"
	10	+	)
	11	+
	12	+	// Node retains XML order and source locations, including expressions. Resolution
	13	+	// turns this syntax tree into the flat, typed emission IR; parsing makes no Go
	14	+	// naming or layout choices.
	15	+	type Node struct {
	16	+	Kind string
	17	+	Attr map[string]string
	18	+	Text string
	19	+	Children []*Node
	20	+	File string
	21	+	Line int
	22	+	}
	23	+
	24	+	func (n *Node) fail(format string, args ...any) error {
	25	+	return fmt.Errorf("%s:%d: %s", n.File, n.Line, fmt.Sprintf(format, args...))
	26	+	}
	27	+
	28	+	// Attribute and child whitelists are per element, not global: a known attribute
	29	+	// or element used in the wrong place is also an error. Documentation is ignored.
	30	+	var attributes = map[string]string{
	31	+	"xcb": "header extension-name extension-xname extension-multiword major-version minor-version",
	32	+	"import": "", "typedef": "oldname newname", "xidtype": "name", "xidunion": "name", "type": "",
	33	+	"enum": "name", "item": "name", "value": "", "bit": "", "struct": "name", "union": "name",
	34	+	"request": "name opcode combine-adjacent", "reply": "", "event": "name number no-sequence-number xge",
	35	+	"eventcopy": "name number ref", "error": "name number type", "errorcopy": "name number ref",
	36	+	"field": "name type enum altenum mask", "pad": "bytes align", "list": "name type enum",
	37	+	"exprfield": "name type", "switch": "name", "bitcase": "", "fieldref": "", "enumref": "ref",
	38	+	"op": "op", "unop": "op", "popcount": "", "doc": "",
	39	+	}
	40	+	var children = map[string]string{
	41	+	"xcb": "import typedef xidtype xidunion enum struct union request event eventcopy error errorcopy doc",
	42	+	"xidunion": "type", "enum": "item doc", "item": "value bit doc",
	43	+	"struct": "field pad list doc", "union": "field pad list doc",
	44	+	"request": "field pad list exprfield switch reply doc", "reply": "field pad list exprfield doc",
	45	+	"event": "field pad list exprfield doc", "error": "field pad doc",
	46	+	"list": "value fieldref op unop popcount enumref", "exprfield": "value fieldref op unop popcount enumref",
	47	+	"switch": "fieldref op unop popcount enumref bitcase", "bitcase": "enumref value field pad doc",
	48	+	"op": "value fieldref op unop popcount enumref", "unop": "value fieldref op unop popcount enumref",
	49	+	"popcount": "value fieldref op unop popcount enumref",
	50	+	}
	51	+
	52	+	func contains(words, word string) bool {
	53	+	for _, s := range strings.Fields(words) {
	54	+	if s == word {
	55	+	return true
	56	+	}
	57	+	}
	58	+	return false
	59	+	}
	60	+
	61	+	func parseFile(path string) (*Node, error) {
	62	+	f, err := os.Open(path)
	63	+	if err != nil {
	64	+	return nil, err
	65	+	}
	66	+	defer f.Close()
	67	+	return parseXML(path, f)
	68	+	}
	69	+	func parseXML(file string, r io.Reader) (*Node, error) {
	70	+	d := xml.NewDecoder(r)
	71	+	var root *Node
	72	+	var stack []*Node
	73	+	for {
	74	+	token, err := d.Token()
	75	+	if err == io.EOF {
	76	+	break
	77	+	}
	78	+	if err != nil {
	79	+	line, _ := d.InputPos()
	80	+	return nil, fmt.Errorf("%s:%d: %w", file, line, err)
	81	+	}
	82	+	switch t := token.(type) {
	83	+	case xml.StartElement:
	84	+	line, _ := d.InputPos()
	85	+	n := &Node{Kind: t.Name.Local, Attr: make(map[string]string), File: file, Line: line}
	86	+	allowed, ok := attributes[n.Kind]
	87	+	if !ok \|\| t.Name.Space != "" {
	88	+	return nil, n.fail("unsupported element <%s>", t.Name.Local)
	89	+	}
	90	+	if len(stack) == 0 {
	91	+	if root != nil \|\| n.Kind != "xcb" {
	92	+	return nil, n.fail("expected a single <xcb> root")
	93	+	}
	94	+	root = n
	95	+	} else {
	96	+	parent := stack[len(stack)-1]
	97	+	if !contains(children[parent.Kind], n.Kind) {
	98	+	return nil, n.fail("unsupported <%s> in <%s>", n.Kind, parent.Kind)
	99	+	}
	100	+	parent.Children = append(parent.Children, n)
	101	+	}
	102	+	if n.Kind == "doc" {
	103	+	if err := d.Skip(); err != nil {
	104	+	return nil, n.fail("invalid doc: %v", err)
	105	+	}
	106	+	continue
	107	+	}
	108	+	for _, a := range t.Attr {
	109	+	if a.Name.Space != "" \|\| !contains(allowed, a.Name.Local) {
	110	+	return nil, n.fail("unknown attribute %q on <%s>", a.Name.Local, n.Kind)
	111	+	}
	112	+	if _, ok := n.Attr[a.Name.Local]; ok {
	113	+	return nil, n.fail("duplicate attribute %q", a.Name.Local)
	114	+	}
	115	+	n.Attr[a.Name.Local] = a.Value
	116	+	}
	117	+	stack = append(stack, n)
	118	+	case xml.EndElement:
	119	+	if len(stack) == 0 {
	120	+	return nil, fmt.Errorf("%s: unexpected closing element", file)
	121	+	}
	122	+	n := stack[len(stack)-1]
	123	+	n.Text = strings.TrimSpace(n.Text)
	124	+	if err := validateNode(n); err != nil {
	125	+	return nil, err
	126	+	}
	127	+	stack = stack[:len(stack)-1]
	128	+	case xml.CharData:
	129	+	if len(stack) > 0 {
	130	+	stack[len(stack)-1].Text += string(t)
	131	+	} else if strings.TrimSpace(string(t)) != "" {
	132	+	return nil, fmt.Errorf("%s: text outside root", file)
	133	+	}
	134	+	case xml.Directive:
	135	+	return nil, fmt.Errorf("%s: XML directives are unsupported", file)
	136	+	}
	137	+	}
	138	+	if root == nil {
	139	+	return nil, fmt.Errorf("%s:1: missing <xcb> root", file)
	140	+	}
	141	+	return root, nil
	142	+	}
	143	+	func require(n *Node, names string) error {
	144	+	for _, name := range strings.Fields(names) {
	145	+	if n.Attr[name] == "" {
	146	+	return n.fail("missing %s on <%s>", name, n.Kind)
	147	+	}
	148	+	}
	149	+	return nil
	150	+	}
	151	+	func number(n *Node, attr string, bits int) error {
	152	+	_, err := strconv.ParseUint(n.Attr[attr], 0, bits)
	153	+	if err != nil {
	154	+	return n.fail("invalid %s %q", attr, n.Attr[attr])
	155	+	}
	156	+	return nil
	157	+	}
	158	+	func exprCount(n *Node) int {
	159	+	count := 0
	160	+	for _, c := range n.Children {
	161	+	if c.Kind != "doc" {
	162	+	count++
	163	+	}
	164	+	}
	165	+	return count
	166	+	}
	167	+	func validateNode(n *Node) error {
	168	+	required := map[string]string{
	169	+	"xcb": "header", "typedef": "oldname newname", "xidtype": "name", "xidunion": "name",
	170	+	"enum": "name", "item": "name", "struct": "name", "union": "name", "request": "name opcode",
	171	+	"event": "name number", "eventcopy": "name number ref", "error": "name number", "errorcopy": "name number ref",
	172	+	"field": "name type", "list": "name type", "exprfield": "name type", "switch": "name", "enumref": "ref", "op": "op", "unop": "op",
	173	+	}
	174	+	if err := require(n, required[n.Kind]); err != nil {
	175	+	return err
	176	+	}
	177	+	switch n.Kind {
	178	+	case "import", "type", "fieldref", "enumref":
	179	+	if n.Text == "" {
	180	+	return n.fail("empty <%s>", n.Kind)
	181	+	}
	182	+	case "value", "bit":
	183	+	if _, err := strconv.ParseInt(n.Text, 0, 64); err != nil {
	184	+	return n.fail("invalid <%s> integer %q", n.Kind, n.Text)
	185	+	}
	186	+	case "pad":
	187	+	_, b := n.Attr["bytes"]
	188	+	_, a := n.Attr["align"]
	189	+	if b == a {
	190	+	return n.fail("pad requires exactly one of bytes or align")
	191	+	}
	192	+	key := "bytes"
	193	+	if a {
	194	+	key = "align"
	195	+	}
	196	+	if err := number(n, key, 31); err != nil {
	197	+	return err
	198	+	}
	199	+	if a {
	200	+	v, _ := strconv.Atoi(n.Attr[key])
	201	+	if v == 0 \|\| v&(v-1) != 0 {
	202	+	return n.fail("pad alignment must be a positive power of two")
	203	+	}
	204	+	}
	205	+	case "request":
	206	+	if err := number(n, "opcode", 8); err != nil {
	207	+	return err
	208	+	}
	209	+	case "event", "eventcopy", "error", "errorcopy":
	210	+	if err := number(n, "number", 8); err != nil {
	211	+	return err
	212	+	}
	213	+	if n.Attr["xge"] == "true" {
	214	+	v, _ := strconv.Atoi(n.Attr["number"])
	215	+	if v >= 128 {
	216	+	return n.fail("xge evtype must be < 128")
	217	+	}
	218	+	}
	219	+	case "op":
	220	+	if !contains("+ - * / & \| << >>", n.Attr["op"]) {
	221	+	return n.fail("unsupported operator %q", n.Attr["op"])
	222	+	}
	223	+	if exprCount(n) != 2 {
	224	+	return n.fail("op requires two operands")
	225	+	}
	226	+	case "unop":
	227	+	if n.Attr["op"] != "~" {
	228	+	return n.fail("unsupported unary operator %q", n.Attr["op"])
	229	+	}
	230	+	if exprCount(n) != 1 {
	231	+	return n.fail("unop requires one operand")
	232	+	}
	233	+	case "popcount", "exprfield", "item":
	234	+	if exprCount(n) != 1 {
	235	+	return n.fail("<%s> requires one expression", n.Kind)
	236	+	}
	237	+	case "list":
	238	+	if exprCount(n) > 1 {
	239	+	return n.fail("list has multiple length expressions")
	240	+	}
	241	+	case "bitcase":
	242	+	fields := 0
	243	+	for _, c := range n.Children {
	244	+	if c.Kind == "field" {
	245	+	fields++
	246	+	if contains("CARD8 CARD16 INT8 INT16 BOOL char BYTE void", c.Attr["type"]) {
	247	+	return c.fail("value-list bitcase requires a 4-byte field")
	248	+	}
	249	+	}
	250	+	}
	251	+	if fields != 1 {
	252	+	return n.fail("value-list bitcase requires exactly one field")
	253	+	}
	254	+	}
	255	+	for _, key := range []string{"xge", "no-sequence-number", "combine-adjacent", "extension-multiword"} {
	256	+	if v, ok := n.Attr[key]; ok && v != "true" && v != "false" {
	257	+	return n.fail("invalid boolean %s=%q", key, v)
	258	+	}
	259	+	}
	260	+	// Forward references cannot be laid out in one pass. Reject at the length
	261	+	// expression's location rather than failing later while emitting Go.
	262	+	declared := map[string]bool{}
	263	+	for _, c := range n.Children {
	264	+	if c.Kind == "field" \|\| c.Kind == "exprfield" {
	265	+	declared[c.Attr["name"]] = true
	266	+	}
	267	+	}
	268	+	seen := map[string]bool{}
	269	+	for _, c := range n.Children {
	270	+	if c.Kind == "list" {
	271	+	var visit func(*Node) error
	272	+	visit = func(e *Node) error {
	273	+	if e.Kind == "fieldref" && declared[e.Text] && !seen[e.Text] {
	274	+	return e.fail("list length references later field %q", e.Text)
	275	+	}
	276	+	for _, child := range e.Children {
	277	+	if err := visit(child); err != nil {
	278	+	return err
	279	+	}
	280	+	}
	281	+	return nil
	282	+	}
	283	+	if err := visit(c); err != nil {
	284	+	return err
	285	+	}
	286	+	}
	287	+	if c.Kind == "field" \|\| c.Kind == "exprfield" {
	288	+	seen[c.Attr["name"]] = true
	289	+	}
	290	+	}
	291	+	return nil
	292	+	}

@@ -0,0 +1,292 @@
	1	+	package main
	2	+
	3	+	import (
	4	+	"encoding/xml"
	5	+	"fmt"
	6	+	"io"
	7	+	"os"
	8	+	"strconv"
	9	+	"strings"
	10	+	)
	11	+
	12	+	// Node retains XML order and source locations, including expressions. Resolution
	13	+	// turns this syntax tree into the flat, typed emission IR; parsing makes no Go
	14	+	// naming or layout choices.
	15	+	type Node struct {
	16	+	Kind string
	17	+	Attr map[string]string
	18	+	Text string
	19	+	Children []*Node
	20	+	File string
	21	+	Line int
	22	+	}
	23	+
	24	+	func (n *Node) fail(format string, args ...any) error {
	25	+	return fmt.Errorf("%s:%d: %s", n.File, n.Line, fmt.Sprintf(format, args...))
	26	+	}
	27	+
	28	+	// Attribute and child whitelists are per element, not global: a known attribute
	29	+	// or element used in the wrong place is also an error. Documentation is ignored.
	30	+	var attributes = map[string]string{
	31	+	"xcb": "header extension-name extension-xname extension-multiword major-version minor-version",
	32	+	"import": "", "typedef": "oldname newname", "xidtype": "name", "xidunion": "name", "type": "",
	33	+	"enum": "name", "item": "name", "value": "", "bit": "", "struct": "name", "union": "name",
	34	+	"request": "name opcode combine-adjacent", "reply": "", "event": "name number no-sequence-number xge",
	35	+	"eventcopy": "name number ref", "error": "name number type", "errorcopy": "name number ref",
	36	+	"field": "name type enum altenum mask", "pad": "bytes align", "list": "name type enum",
	37	+	"exprfield": "name type", "switch": "name", "bitcase": "", "fieldref": "", "enumref": "ref",
	38	+	"op": "op", "unop": "op", "popcount": "", "doc": "",
	39	+	}
	40	+	var children = map[string]string{
	41	+	"xcb": "import typedef xidtype xidunion enum struct union request event eventcopy error errorcopy doc",
	42	+	"xidunion": "type", "enum": "item doc", "item": "value bit doc",
	43	+	"struct": "field pad list doc", "union": "field pad list doc",
	44	+	"request": "field pad list exprfield switch reply doc", "reply": "field pad list exprfield doc",
	45	+	"event": "field pad list exprfield doc", "error": "field pad doc",
	46	+	"list": "value fieldref op unop popcount enumref", "exprfield": "value fieldref op unop popcount enumref",
	47	+	"switch": "fieldref op unop popcount enumref bitcase", "bitcase": "enumref value field pad doc",
	48	+	"op": "value fieldref op unop popcount enumref", "unop": "value fieldref op unop popcount enumref",
	49	+	"popcount": "value fieldref op unop popcount enumref",
	50	+	}
	51	+
	52	+	func contains(words, word string) bool {
	53	+	for _, s := range strings.Fields(words) {
	54	+	if s == word {
	55	+	return true
	56	+	}
	57	+	}
	58	+	return false
	59	+	}
	60	+
	61	+	func parseFile(path string) (*Node, error) {
	62	+	f, err := os.Open(path)
	63	+	if err != nil {
	64	+	return nil, err
	65	+	}
	66	+	defer f.Close()
	67	+	return parseXML(path, f)
	68	+	}
	69	+	func parseXML(file string, r io.Reader) (*Node, error) {
	70	+	d := xml.NewDecoder(r)
	71	+	var root *Node
	72	+	var stack []*Node
	73	+	for {
	74	+	token, err := d.Token()
	75	+	if err == io.EOF {
	76	+	break
	77	+	}
	78	+	if err != nil {
	79	+	line, _ := d.InputPos()
	80	+	return nil, fmt.Errorf("%s:%d: %w", file, line, err)
	81	+	}
	82	+	switch t := token.(type) {
	83	+	case xml.StartElement:
	84	+	line, _ := d.InputPos()
	85	+	n := &Node{Kind: t.Name.Local, Attr: make(map[string]string), File: file, Line: line}
	86	+	allowed, ok := attributes[n.Kind]
	87	+	if !ok \|\| t.Name.Space != "" {
	88	+	return nil, n.fail("unsupported element <%s>", t.Name.Local)
	89	+	}
	90	+	if len(stack) == 0 {
	91	+	if root != nil \|\| n.Kind != "xcb" {
	92	+	return nil, n.fail("expected a single <xcb> root")
	93	+	}
	94	+	root = n
	95	+	} else {
	96	+	parent := stack[len(stack)-1]
	97	+	if !contains(children[parent.Kind], n.Kind) {
	98	+	return nil, n.fail("unsupported <%s> in <%s>", n.Kind, parent.Kind)
	99	+	}
	100	+	parent.Children = append(parent.Children, n)
	101	+	}
	102	+	if n.Kind == "doc" {
	103	+	if err := d.Skip(); err != nil {
	104	+	return nil, n.fail("invalid doc: %v", err)
	105	+	}
	106	+	continue
	107	+	}
	108	+	for _, a := range t.Attr {
	109	+	if a.Name.Space != "" \|\| !contains(allowed, a.Name.Local) {
	110	+	return nil, n.fail("unknown attribute %q on <%s>", a.Name.Local, n.Kind)
	111	+	}
	112	+	if _, ok := n.Attr[a.Name.Local]; ok {
	113	+	return nil, n.fail("duplicate attribute %q", a.Name.Local)
	114	+	}
	115	+	n.Attr[a.Name.Local] = a.Value
	116	+	}
	117	+	stack = append(stack, n)
	118	+	case xml.EndElement:
	119	+	if len(stack) == 0 {
	120	+	return nil, fmt.Errorf("%s: unexpected closing element", file)
	121	+	}
	122	+	n := stack[len(stack)-1]
	123	+	n.Text = strings.TrimSpace(n.Text)
	124	+	if err := validateNode(n); err != nil {
	125	+	return nil, err
	126	+	}
	127	+	stack = stack[:len(stack)-1]
	128	+	case xml.CharData:
	129	+	if len(stack) > 0 {
	130	+	stack[len(stack)-1].Text += string(t)
	131	+	} else if strings.TrimSpace(string(t)) != "" {
	132	+	return nil, fmt.Errorf("%s: text outside root", file)
	133	+	}
	134	+	case xml.Directive:
	135	+	return nil, fmt.Errorf("%s: XML directives are unsupported", file)
	136	+	}
	137	+	}
	138	+	if root == nil {
	139	+	return nil, fmt.Errorf("%s:1: missing <xcb> root", file)
	140	+	}
	141	+	return root, nil
	142	+	}
	143	+	func require(n *Node, names string) error {
	144	+	for _, name := range strings.Fields(names) {
	145	+	if n.Attr[name] == "" {
	146	+	return n.fail("missing %s on <%s>", name, n.Kind)
	147	+	}
	148	+	}
	149	+	return nil
	150	+	}
	151	+	func number(n *Node, attr string, bits int) error {
	152	+	_, err := strconv.ParseUint(n.Attr[attr], 0, bits)
	153	+	if err != nil {
	154	+	return n.fail("invalid %s %q", attr, n.Attr[attr])
	155	+	}
	156	+	return nil
	157	+	}
	158	+	func exprCount(n *Node) int {
	159	+	count := 0
	160	+	for _, c := range n.Children {
	161	+	if c.Kind != "doc" {
	162	+	count++
	163	+	}
	164	+	}
	165	+	return count
	166	+	}
	167	+	func validateNode(n *Node) error {
	168	+	required := map[string]string{
	169	+	"xcb": "header", "typedef": "oldname newname", "xidtype": "name", "xidunion": "name",
	170	+	"enum": "name", "item": "name", "struct": "name", "union": "name", "request": "name opcode",
	171	+	"event": "name number", "eventcopy": "name number ref", "error": "name number", "errorcopy": "name number ref",
	172	+	"field": "name type", "list": "name type", "exprfield": "name type", "switch": "name", "enumref": "ref", "op": "op", "unop": "op",
	173	+	}
	174	+	if err := require(n, required[n.Kind]); err != nil {
	175	+	return err
	176	+	}
	177	+	switch n.Kind {
	178	+	case "import", "type", "fieldref", "enumref":
	179	+	if n.Text == "" {
	180	+	return n.fail("empty <%s>", n.Kind)
	181	+	}
	182	+	case "value", "bit":
	183	+	if _, err := strconv.ParseInt(n.Text, 0, 64); err != nil {
	184	+	return n.fail("invalid <%s> integer %q", n.Kind, n.Text)
	185	+	}
	186	+	case "pad":
	187	+	_, b := n.Attr["bytes"]
	188	+	_, a := n.Attr["align"]
	189	+	if b == a {
	190	+	return n.fail("pad requires exactly one of bytes or align")
	191	+	}
	192	+	key := "bytes"
	193	+	if a {
	194	+	key = "align"
	195	+	}
	196	+	if err := number(n, key, 31); err != nil {
	197	+	return err
	198	+	}
	199	+	if a {
	200	+	v, _ := strconv.Atoi(n.Attr[key])
	201	+	if v == 0 \|\| v&(v-1) != 0 {
	202	+	return n.fail("pad alignment must be a positive power of two")
	203	+	}
	204	+	}
	205	+	case "request":
	206	+	if err := number(n, "opcode", 8); err != nil {
	207	+	return err
	208	+	}
	209	+	case "event", "eventcopy", "error", "errorcopy":
	210	+	if err := number(n, "number", 8); err != nil {
	211	+	return err
	212	+	}
	213	+	if n.Attr["xge"] == "true" {
	214	+	v, _ := strconv.Atoi(n.Attr["number"])
	215	+	if v >= 128 {
	216	+	return n.fail("xge evtype must be < 128")
	217	+	}
	218	+	}
	219	+	case "op":
	220	+	if !contains("+ - * / & \| << >>", n.Attr["op"]) {
	221	+	return n.fail("unsupported operator %q", n.Attr["op"])
	222	+	}
	223	+	if exprCount(n) != 2 {
	224	+	return n.fail("op requires two operands")
	225	+	}
	226	+	case "unop":
	227	+	if n.Attr["op"] != "~" {
	228	+	return n.fail("unsupported unary operator %q", n.Attr["op"])
	229	+	}
	230	+	if exprCount(n) != 1 {
	231	+	return n.fail("unop requires one operand")
	232	+	}
	233	+	case "popcount", "exprfield", "item":
	234	+	if exprCount(n) != 1 {
	235	+	return n.fail("<%s> requires one expression", n.Kind)
	236	+	}
	237	+	case "list":
	238	+	if exprCount(n) > 1 {
	239	+	return n.fail("list has multiple length expressions")
	240	+	}
	241	+	case "bitcase":
	242	+	fields := 0
	243	+	for _, c := range n.Children {
	244	+	if c.Kind == "field" {
	245	+	fields++
	246	+	if contains("CARD8 CARD16 INT8 INT16 BOOL char BYTE void", c.Attr["type"]) {
	247	+	return c.fail("value-list bitcase requires a 4-byte field")
	248	+	}
	249	+	}
	250	+	}
	251	+	if fields != 1 {
	252	+	return n.fail("value-list bitcase requires exactly one field")
	253	+	}
	254	+	}
	255	+	for _, key := range []string{"xge", "no-sequence-number", "combine-adjacent", "extension-multiword"} {
	256	+	if v, ok := n.Attr[key]; ok && v != "true" && v != "false" {
	257	+	return n.fail("invalid boolean %s=%q", key, v)
	258	+	}
	259	+	}
	260	+	// Forward references cannot be laid out in one pass. Reject at the length
	261	+	// expression's location rather than failing later while emitting Go.
	262	+	declared := map[string]bool{}
	263	+	for _, c := range n.Children {
	264	+	if c.Kind == "field" \|\| c.Kind == "exprfield" {
	265	+	declared[c.Attr["name"]] = true
	266	+	}
	267	+	}
	268	+	seen := map[string]bool{}
	269	+	for _, c := range n.Children {
	270	+	if c.Kind == "list" {
	271	+	var visit func(*Node) error
	272	+	visit = func(e *Node) error {
	273	+	if e.Kind == "fieldref" && declared[e.Text] && !seen[e.Text] {
	274	+	return e.fail("list length references later field %q", e.Text)
	275	+	}
	276	+	for _, child := range e.Children {
	277	+	if err := visit(child); err != nil {
	278	+	return err
	279	+	}
	280	+	}
	281	+	return nil
	282	+	}
	283	+	if err := visit(c); err != nil {
	284	+	return err
	285	+	}
	286	+	}
	287	+	if c.Kind == "field" \|\| c.Kind == "exprfield" {
	288	+	seen[c.Attr["name"]] = true
	289	+	}
	290	+	}
	291	+	return nil
	292	+	}

A cmd/xtgen/parse_test.go +74 -0

@@ -0,0 +1,74 @@
	1	+	package main
	2	+
	3	+	import (
	4	+	"path/filepath"
	5	+	"strings"
	6	+	"testing"
	7	+	)
	8	+
	9	+	func TestParseVendored(t *testing.T) {
	10	+	files, err := filepath.Glob("../../spec/xml/*.xml")
	11	+	if err != nil {
	12	+	t.Fatal(err)
	13	+	}
	14	+	if len(files) != 9 {
	15	+	t.Fatalf("got %d XML files, want 9", len(files))
	16	+	}
	17	+	for _, file := range files {
	18	+	t.Run(filepath.Base(file), func(t *testing.T) {
	19	+	n, err := parseFile(file)
	20	+	if err != nil {
	21	+	t.Fatal(err)
	22	+	}
	23	+	if n.Kind != "xcb" \|\| len(n.Children) == 0 {
	24	+	t.Fatal("missing module AST")
	25	+	}
	26	+	})
	27	+	}
	28	+	}
	29	+	func TestParseRejects(t *testing.T) {
	30	+	cases := []struct{ name, body, want string }{
	31	+	{"unknown element", "<surprise/>", "unsupported element"},
	32	+	{"unknown attribute", `<xidtype name="WINDOW" surprise="yes"/>`, "unknown attribute"},
	33	+	{"misplaced known element", `<struct name="S"><reply/></struct>`, "unsupported <reply>"},
	34	+	{"sumof", `<request name="R" opcode="1"><list name="a" type="CARD8"><sumof ref="a"/></list></request>`, "sumof"},
	35	+	{"paramref", `<request name="R" opcode="1"><list name="a" type="CARD8"><paramref type="CARD8">a</paramref></list></request>`, "paramref"},
	36	+	{"case", `<request name="R" opcode="1"><switch name="s"><case/></switch></request>`, "case"},
	37	+	{"struct switch", `<struct name="S"><switch name="s"/></struct>`, "unsupported <switch>"},
	38	+	{"reply switch", `<request name="R" opcode="1"><reply><switch name="s"/></reply></request>`, "unsupported <switch>"},
	39	+	{"nested switch", `<request name="R" opcode="1"><switch name="s"><bitcase><switch name="s"/></bitcase></switch></request>`, "unsupported <switch>"},
	40	+	{"fd", `<request name="R" opcode="1"><fd name="fd"/></request>`, "fd"},
	41	+	{"eventstruct", `<eventstruct name="E"/>`, "eventstruct"},
	42	+	{"required alignment", `<struct name="S"><required_start_align align="4"/></struct>`, "required_start_align"},
	43	+	{"forward length", `<struct name="S"><list name="a" type="CARD8"><fieldref>n</fieldref></list><field name="n" type="CARD8"/></struct>`, "later field"},
	44	+	{"xge code", `<event name="E" number="128" xge="true"/>`, "evtype"},
	45	+	{"bad opcode", `<request name="R" opcode="256"/>`, "invalid opcode"},
	46	+	{"bad operator", `<request name="R" opcode="1"><exprfield name="x" type="CARD32"><op op="%"><value>1</value><value>2</value></op></exprfield></request>`, "unsupported operator"},
	47	+	{"wrong operands", `<request name="R" opcode="1"><exprfield name="x" type="CARD32"><op op="+"><value>1</value></op></exprfield></request>`, "two operands"},
	48	+	{"bad pad", `<struct name="S"><pad align="3"/></struct>`, "power of two"},
	49	+	{"namespace", `<xidtype xmlns="other" name="X"/>`, "unsupported element"},
	50	+	{"duplicate attr", `<xidtype name="X" name="Y"/>`, "duplicate attribute"},
	51	+	}
	52	+	for _, tc := range cases {
	53	+	t.Run(tc.name, func(t *testing.T) {
	54	+	_, err := parseXML("bad.xml", strings.NewReader("<xcb header=\"test\">\n"+tc.body+"\n</xcb>"))
	55	+	if err == nil \|\| !strings.Contains(err.Error(), tc.want) \|\| !strings.Contains(err.Error(), "bad.xml:2:") {
	56	+	t.Fatalf("got %v, want file:line and %q", err, tc.want)
	57	+	}
	58	+	})
	59	+	}
	60	+	}
	61	+	func TestParseAST(t *testing.T) {
	62	+	n, err := parseXML("ok.xml", strings.NewReader(`<xcb header="a"><doc><arbitrary/></doc><request name="R" opcode="1"><field type="CARD32" name="n"/><list type="CARD8" name="data"><op op="*"><fieldref>n</fieldref><value>4</value></op></list></request></xcb>`))
	63	+	if err != nil {
	64	+	t.Fatal(err)
	65	+	}
	66	+	r := n.Children[1]
	67	+	if r.Attr["name"] != "R" \|\| r.Children[1].Children[0].Children[0].Text != "n" {
	68	+	t.Fatal("AST lost order or expression")
	69	+	}
	70	+	}
	71	+	func FuzzParseXML(f *testing.F) {
	72	+	f.Add(`<xcb header="test"/>`)
	73	+	f.Fuzz(func(t *testing.T, raw string) { _, _ = parseXML("fuzz.xml", strings.NewReader(raw)) })
	74	+	}

@@ -0,0 +1,74 @@
	1	+	package main
	2	+
	3	+	import (
	4	+	"path/filepath"
	5	+	"strings"
	6	+	"testing"
	7	+	)
	8	+
	9	+	func TestParseVendored(t *testing.T) {
	10	+	files, err := filepath.Glob("../../spec/xml/*.xml")
	11	+	if err != nil {
	12	+	t.Fatal(err)
	13	+	}
	14	+	if len(files) != 9 {
	15	+	t.Fatalf("got %d XML files, want 9", len(files))
	16	+	}
	17	+	for _, file := range files {
	18	+	t.Run(filepath.Base(file), func(t *testing.T) {
	19	+	n, err := parseFile(file)
	20	+	if err != nil {
	21	+	t.Fatal(err)
	22	+	}
	23	+	if n.Kind != "xcb" \|\| len(n.Children) == 0 {
	24	+	t.Fatal("missing module AST")
	25	+	}
	26	+	})
	27	+	}
	28	+	}
	29	+	func TestParseRejects(t *testing.T) {
	30	+	cases := []struct{ name, body, want string }{
	31	+	{"unknown element", "<surprise/>", "unsupported element"},
	32	+	{"unknown attribute", `<xidtype name="WINDOW" surprise="yes"/>`, "unknown attribute"},
	33	+	{"misplaced known element", `<struct name="S"><reply/></struct>`, "unsupported <reply>"},
	34	+	{"sumof", `<request name="R" opcode="1"><list name="a" type="CARD8"><sumof ref="a"/></list></request>`, "sumof"},
	35	+	{"paramref", `<request name="R" opcode="1"><list name="a" type="CARD8"><paramref type="CARD8">a</paramref></list></request>`, "paramref"},
	36	+	{"case", `<request name="R" opcode="1"><switch name="s"><case/></switch></request>`, "case"},
	37	+	{"struct switch", `<struct name="S"><switch name="s"/></struct>`, "unsupported <switch>"},
	38	+	{"reply switch", `<request name="R" opcode="1"><reply><switch name="s"/></reply></request>`, "unsupported <switch>"},
	39	+	{"nested switch", `<request name="R" opcode="1"><switch name="s"><bitcase><switch name="s"/></bitcase></switch></request>`, "unsupported <switch>"},
	40	+	{"fd", `<request name="R" opcode="1"><fd name="fd"/></request>`, "fd"},
	41	+	{"eventstruct", `<eventstruct name="E"/>`, "eventstruct"},
	42	+	{"required alignment", `<struct name="S"><required_start_align align="4"/></struct>`, "required_start_align"},
	43	+	{"forward length", `<struct name="S"><list name="a" type="CARD8"><fieldref>n</fieldref></list><field name="n" type="CARD8"/></struct>`, "later field"},
	44	+	{"xge code", `<event name="E" number="128" xge="true"/>`, "evtype"},
	45	+	{"bad opcode", `<request name="R" opcode="256"/>`, "invalid opcode"},
	46	+	{"bad operator", `<request name="R" opcode="1"><exprfield name="x" type="CARD32"><op op="%"><value>1</value><value>2</value></op></exprfield></request>`, "unsupported operator"},
	47	+	{"wrong operands", `<request name="R" opcode="1"><exprfield name="x" type="CARD32"><op op="+"><value>1</value></op></exprfield></request>`, "two operands"},
	48	+	{"bad pad", `<struct name="S"><pad align="3"/></struct>`, "power of two"},
	49	+	{"namespace", `<xidtype xmlns="other" name="X"/>`, "unsupported element"},
	50	+	{"duplicate attr", `<xidtype name="X" name="Y"/>`, "duplicate attribute"},
	51	+	}
	52	+	for _, tc := range cases {
	53	+	t.Run(tc.name, func(t *testing.T) {
	54	+	_, err := parseXML("bad.xml", strings.NewReader("<xcb header=\"test\">\n"+tc.body+"\n</xcb>"))
	55	+	if err == nil \|\| !strings.Contains(err.Error(), tc.want) \|\| !strings.Contains(err.Error(), "bad.xml:2:") {
	56	+	t.Fatalf("got %v, want file:line and %q", err, tc.want)
	57	+	}
	58	+	})
	59	+	}
	60	+	}
	61	+	func TestParseAST(t *testing.T) {
	62	+	n, err := parseXML("ok.xml", strings.NewReader(`<xcb header="a"><doc><arbitrary/></doc><request name="R" opcode="1"><field type="CARD32" name="n"/><list type="CARD8" name="data"><op op="*"><fieldref>n</fieldref><value>4</value></op></list></request></xcb>`))
	63	+	if err != nil {
	64	+	t.Fatal(err)
	65	+	}
	66	+	r := n.Children[1]
	67	+	if r.Attr["name"] != "R" \|\| r.Children[1].Children[0].Children[0].Text != "n" {
	68	+	t.Fatal("AST lost order or expression")
	69	+	}
	70	+	}
	71	+	func FuzzParseXML(f *testing.F) {
	72	+	f.Add(`<xcb header="test"/>`)
	73	+	f.Fuzz(func(t *testing.T, raw string) { _, _ = parseXML("fuzz.xml", strings.NewReader(raw)) })
	74	+	}