tools/src/cmd/check-spec-examples/main.go - tint - Git at Google

 // Copyright 2021 The Tint Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.

 // check-spec-examples tests that WGSL specification examples compile as
 // expected.
 //
 // The tool parses the WGSL HTML specification from the web or from a local file
 // and then runs the WGSL compiler for all examples annotated with the 'wgsl'
 // and 'global-scope' or 'function-scope' HTML class types.
 //
 // To run:
 //   go get golang.org/x/net/html # Only required once
 //   go run tools/check-spec-examples/main.go --compiler=<path-to-tint>
 package main

 import (
 	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"strings"

 	"golang.org/x/net/html"
 )

 const (
 	toolName        = "check-spec-examples"
 	defaultSpecPath = "https://gpuweb.github.io/gpuweb/wgsl/"
 )

 var (
 	errInvalidArg = errors.New("Invalid arguments")
 )

 func main() {
 	flag.Usage = func() {
 		out := flag.CommandLine.Output()
 		fmt.Fprintf(out, "%v tests that WGSL specification examples compile as expected.\n", toolName)
 		fmt.Fprintf(out, "\n")
 		fmt.Fprintf(out, "Usage:\n")
 		fmt.Fprintf(out, "  %s [spec] [flags]\n", toolName)
 		fmt.Fprintf(out, "\n")
 		fmt.Fprintf(out, "spec is an optional local file path or URL to the WGSL specification.\n")
 		fmt.Fprintf(out, "If spec is omitted then the specification is fetched from %v\n", defaultSpecPath)
 		fmt.Fprintf(out, "\n")
 		fmt.Fprintf(out, "flags may be any combination of:\n")
 		flag.PrintDefaults()
 	}

 	err := run()
 	switch err {
 	case nil:
 		return
 	case errInvalidArg:
 		fmt.Fprintf(os.Stderr, "Error: %v\n\n", err)
 		flag.Usage()
 	default:
 		fmt.Fprintf(os.Stderr, "%v\n", err)
 	}
 	os.Exit(1)
 }

 func run() error {
 	// Parse flags
 	compilerPath := flag.String("compiler", "tint", "path to compiler executable")
 	verbose := flag.Bool("verbose", false, "print examples that pass")
 	flag.Parse()

 	// Try to find the WGSL compiler
 	compiler, err := exec.LookPath(*compilerPath)
 	if err != nil {
 		return fmt.Errorf("Failed to find WGSL compiler: %w", err)
 	}
 	if compiler, err = filepath.Abs(compiler); err != nil {
 		return fmt.Errorf("Failed to find WGSL compiler: %w", err)
 	}

 	// Check for explicit WGSL spec path
 	args := flag.Args()
 	specURL, _ := url.Parse(defaultSpecPath)
 	switch len(args) {
 	case 0:
 	case 1:
 		var err error
 		specURL, err = url.Parse(args[0])
 		if err != nil {
 			return err
 		}
 	default:
 		if len(args) > 1 {
 			return errInvalidArg
 		}
 	}

 	// The specURL might just be a local file path, in which case automatically
 	// add the 'file' URL scheme
 	if specURL.Scheme == "" {
 		specURL.Scheme = "file"
 	}

 	// Open the spec from HTTP(S) or from a local file
 	var specContent io.ReadCloser
 	switch specURL.Scheme {
 	case "http", "https":
 		response, err := http.Get(specURL.String())
 		if err != nil {
 			return fmt.Errorf("Failed to load the WGSL spec from '%v': %w", specURL, err)
 		}
 		specContent = response.Body
 	case "file":
 		specURL.Path, err = filepath.Abs(specURL.Path)
 		if err != nil {
 			return fmt.Errorf("Failed to load the WGSL spec from '%v': %w", specURL, err)
 		}

 		file, err := os.Open(specURL.Path)
 		if err != nil {
 			return fmt.Errorf("Failed to load the WGSL spec from '%v': %w", specURL, err)
 		}
 		specContent = file
 	default:
 		return fmt.Errorf("Unsupported URL scheme: %v", specURL.Scheme)
 	}
 	defer specContent.Close()

 	// Create the HTML parser
 	doc, err := html.Parse(specContent)
 	if err != nil {
 		return err
 	}

 	// Parse all the WGSL examples
 	examples := []example{}
 	if err := gatherExamples(doc, &examples); err != nil {
 		return err
 	}

 	if len(examples) == 0 {
 		return fmt.Errorf("no examples found")
 	}

 	// Create a temporary directory to hold the examples as separate files
 	tmpDir, err := ioutil.TempDir("", "wgsl-spec-examples")
 	if err != nil {
 		return err
 	}
 	if err := os.MkdirAll(tmpDir, 0666); err != nil {
 		return fmt.Errorf("Failed to create temporary directory: %w", err)
 	}
 	defer os.RemoveAll(tmpDir)

 	// For each compilable WGSL example...
 	for _, e := range examples {
 		exampleURL := specURL.String() + "#" + e.name

 		if err := tryCompile(compiler, tmpDir, e); err != nil {
 			if !e.expectError {
 				fmt.Printf("✘ %v ✘\n%v\n", exampleURL, err)
 				continue
 			}
 		} else if e.expectError {
 			fmt.Printf("✘ %v ✘\nCompiled even though it was marked with 'expect-error'\n", exampleURL)
 		}
 		if *verbose {
 			fmt.Printf("✔ %v ✔\n", exampleURL)
 		}
 	}
 	return nil
 }

 // Holds all the information about a single, compilable WGSL example in the spec
 type example struct {
 	name          string // The name (typically hash generated by bikeshed)
 	code          string // The example source
 	globalScope   bool   // Annotated with 'global-scope' ?
 	functionScope bool   // Annotated with 'function-scope' ?
 	expectError   bool   // Annotated with 'expect-error' ?
 }

 // tryCompile attempts to compile the example e in the directory wd, using the
 // compiler at the given path. If the example is annotated with 'function-scope'
 // then the code is wrapped with a basic vertex-stage-entry function.
 // If the first compile fails then a dummy vertex-state-entry function is
 // appended to the source, and another attempt to compile the shader is made.
 func tryCompile(compiler, wd string, e example) error {
 	code := e.code
 	if e.functionScope {
 		code = "\n[[stage(vertex)]] fn main() -> [[builtin(position)]] vec4<f32> {\n" + code + " return vec4<f32>();}\n"
 	}

 	addedStubFunction := false
 	for {
 		err := compile(compiler, wd, e.name, code)
 		if err == nil {
 			return nil
 		}

 		if !addedStubFunction {
 			code += "\n[[stage(vertex)]] fn main() {}\n"
 			addedStubFunction = true
 			continue
 		}

 		return err
 	}
 }

 // compile creates a file in wd and uses the compiler to attempt to compile it.
 func compile(compiler, wd, name, code string) error {
 	filename := name + ".wgsl"
 	path := filepath.Join(wd, filename)
 	if err := ioutil.WriteFile(path, []byte(code), 0666); err != nil {
 		return fmt.Errorf("Failed to write example file '%v'", path)
 	}
 	cmd := exec.Command(compiler, filename)
 	cmd.Dir = wd
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		return fmt.Errorf("%v\n%v", err, string(out))
 	}
 	return nil
 }

 // gatherExamples scans the HTML node and its children for blocks that contain
 // WGSL example code, populating the examples slice.
 func gatherExamples(node *html.Node, examples *[]example) error {
 	if hasClass(node, "example") && hasClass(node, "wgsl") {
 		e := example{
 			name:          nodeID(node),
 			code:          exampleCode(node),
 			globalScope:   hasClass(node, "global-scope"),
 			functionScope: hasClass(node, "function-scope"),
 			expectError:   hasClass(node, "expect-error"),
 		}
 		// If the example is annotated with a scope, then it can be compiled.
 		if e.globalScope || e.functionScope {
 			*examples = append(*examples, e)
 		}
 	}
 	for child := node.FirstChild; child != nil; child = child.NextSibling {
 		if err := gatherExamples(child, examples); err != nil {
 			return err
 		}
 	}
 	return nil
 }

 // exampleCode returns a string formed from all the TextNodes found in <pre>
 // blocks that are children of node.
 func exampleCode(node *html.Node) string {
 	sb := strings.Builder{}
 	for child := node.FirstChild; child != nil; child = child.NextSibling {
 		if child.Data == "pre" {
 			printNodeText(child, &sb)
 		}
 	}
 	return sb.String()
 }

 // printNodeText traverses node and its children, writing the Data of all
 // TextNodes to sb.
 func printNodeText(node *html.Node, sb *strings.Builder) {
 	if node.Type == html.TextNode {
 		sb.WriteString(node.Data)
 	}

 	for child := node.FirstChild; child != nil; child = child.NextSibling {
 		printNodeText(child, sb)
 	}
 }

 // hasClass returns true iff node is has the given "class" attribute.
 func hasClass(node *html.Node, class string) bool {
 	for _, attr := range node.Attr {
 		if attr.Key == "class" {
 			classes := strings.Split(attr.Val, " ")
 			for _, c := range classes {
 				if c == class {
 					return true
 				}
 			}
 		}
 	}
 	return false
 }

 // nodeID returns the given "id" attribute of node, or an empty string if there
 // is no "id" attribute.
 func nodeID(node *html.Node) string {
 	for _, attr := range node.Attr {
 		if attr.Key == "id" {
 			return attr.Val
 		}
 	}
 	return ""
 }
	// Copyright 2021 The Tint Authors.
	//
	// Licensed under the Apache License, Version 2.0 (the "License");
	// you may not use this file except in compliance with the License.
	// You may obtain a copy of the License at
	//
	// http://www.apache.org/licenses/LICENSE-2.0
	//
	// Unless required by applicable law or agreed to in writing, software
	// distributed under the License is distributed on an "AS IS" BASIS,
	// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	// See the License for the specific language governing permissions and
	// limitations under the License.

	// check-spec-examples tests that WGSL specification examples compile as
	// expected.
	//
	// The tool parses the WGSL HTML specification from the web or from a local file
	// and then runs the WGSL compiler for all examples annotated with the 'wgsl'
	// and 'global-scope' or 'function-scope' HTML class types.
	//
	// To run:
	// go get golang.org/x/net/html # Only required once
	// go run tools/check-spec-examples/main.go --compiler=<path-to-tint>
	package main

	import (
	"errors"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"os/exec"
	"path/filepath"
	"strings"

	"golang.org/x/net/html"
	)

	const (
	toolName = "check-spec-examples"
	defaultSpecPath = "https://gpuweb.github.io/gpuweb/wgsl/"
	)

	var (
	errInvalidArg = errors.New("Invalid arguments")
	)

	func main() {
	flag.Usage = func() {
	out := flag.CommandLine.Output()
	fmt.Fprintf(out, "%v tests that WGSL specification examples compile as expected.\n", toolName)
	fmt.Fprintf(out, "\n")
	fmt.Fprintf(out, "Usage:\n")
	fmt.Fprintf(out, " %s [spec] [flags]\n", toolName)
	fmt.Fprintf(out, "\n")
	fmt.Fprintf(out, "spec is an optional local file path or URL to the WGSL specification.\n")
	fmt.Fprintf(out, "If spec is omitted then the specification is fetched from %v\n", defaultSpecPath)
	fmt.Fprintf(out, "\n")
	fmt.Fprintf(out, "flags may be any combination of:\n")
	flag.PrintDefaults()
	}

	err := run()
	switch err {
	case nil:
	return
	case errInvalidArg:
	fmt.Fprintf(os.Stderr, "Error: %v\n\n", err)
	flag.Usage()
	default:
	fmt.Fprintf(os.Stderr, "%v\n", err)
	}
	os.Exit(1)
	}

	func run() error {
	// Parse flags
	compilerPath := flag.String("compiler", "tint", "path to compiler executable")
	verbose := flag.Bool("verbose", false, "print examples that pass")
	flag.Parse()

	// Try to find the WGSL compiler
	compiler, err := exec.LookPath(*compilerPath)
	if err != nil {
	return fmt.Errorf("Failed to find WGSL compiler: %w", err)
	}
	if compiler, err = filepath.Abs(compiler); err != nil {
	return fmt.Errorf("Failed to find WGSL compiler: %w", err)
	}

	// Check for explicit WGSL spec path
	args := flag.Args()
	specURL, _ := url.Parse(defaultSpecPath)
	switch len(args) {
	case 0:
	case 1:
	var err error
	specURL, err = url.Parse(args[0])
	if err != nil {
	return err
	}
	default:
	if len(args) > 1 {
	return errInvalidArg
	}
	}

	// The specURL might just be a local file path, in which case automatically
	// add the 'file' URL scheme
	if specURL.Scheme == "" {
	specURL.Scheme = "file"
	}

	// Open the spec from HTTP(S) or from a local file
	var specContent io.ReadCloser
	switch specURL.Scheme {
	case "http", "https":
	response, err := http.Get(specURL.String())
	if err != nil {
	return fmt.Errorf("Failed to load the WGSL spec from '%v': %w", specURL, err)
	}
	specContent = response.Body
	case "file":
	specURL.Path, err = filepath.Abs(specURL.Path)
	if err != nil {
	return fmt.Errorf("Failed to load the WGSL spec from '%v': %w", specURL, err)
	}

	file, err := os.Open(specURL.Path)
	if err != nil {
	return fmt.Errorf("Failed to load the WGSL spec from '%v': %w", specURL, err)
	}
	specContent = file
	default:
	return fmt.Errorf("Unsupported URL scheme: %v", specURL.Scheme)
	}
	defer specContent.Close()

	// Create the HTML parser
	doc, err := html.Parse(specContent)
	if err != nil {
	return err
	}

	// Parse all the WGSL examples
	examples := []example{}
	if err := gatherExamples(doc, &examples); err != nil {
	return err
	}

	if len(examples) == 0 {
	return fmt.Errorf("no examples found")
	}

	// Create a temporary directory to hold the examples as separate files
	tmpDir, err := ioutil.TempDir("", "wgsl-spec-examples")
	if err != nil {
	return err
	}
	if err := os.MkdirAll(tmpDir, 0666); err != nil {
	return fmt.Errorf("Failed to create temporary directory: %w", err)
	}
	defer os.RemoveAll(tmpDir)

	// For each compilable WGSL example...
	for _, e := range examples {
	exampleURL := specURL.String() + "#" + e.name

	if err := tryCompile(compiler, tmpDir, e); err != nil {
	if !e.expectError {
	fmt.Printf("✘ %v ✘\n%v\n", exampleURL, err)
	continue
	}
	} else if e.expectError {
	fmt.Printf("✘ %v ✘\nCompiled even though it was marked with 'expect-error'\n", exampleURL)
	}
	if *verbose {
	fmt.Printf("✔ %v ✔\n", exampleURL)
	}
	}
	return nil
	}

	// Holds all the information about a single, compilable WGSL example in the spec
	type example struct {
	name string // The name (typically hash generated by bikeshed)
	code string // The example source
	globalScope bool // Annotated with 'global-scope' ?
	functionScope bool // Annotated with 'function-scope' ?
	expectError bool // Annotated with 'expect-error' ?
	}

	// tryCompile attempts to compile the example e in the directory wd, using the
	// compiler at the given path. If the example is annotated with 'function-scope'
	// then the code is wrapped with a basic vertex-stage-entry function.
	// If the first compile fails then a dummy vertex-state-entry function is
	// appended to the source, and another attempt to compile the shader is made.
	func tryCompile(compiler, wd string, e example) error {
	code := e.code
	if e.functionScope {
	code = "\n[[stage(vertex)]] fn main() -> [[builtin(position)]] vec4<f32> {\n" + code + " return vec4<f32>();}\n"
	}

	addedStubFunction := false
	for {
	err := compile(compiler, wd, e.name, code)
	if err == nil {
	return nil
	}

	if !addedStubFunction {
	code += "\n[[stage(vertex)]] fn main() {}\n"
	addedStubFunction = true
	continue
	}

	return err
	}
	}

	// compile creates a file in wd and uses the compiler to attempt to compile it.
	func compile(compiler, wd, name, code string) error {
	filename := name + ".wgsl"
	path := filepath.Join(wd, filename)
	if err := ioutil.WriteFile(path, []byte(code), 0666); err != nil {
	return fmt.Errorf("Failed to write example file '%v'", path)
	}
	cmd := exec.Command(compiler, filename)
	cmd.Dir = wd
	out, err := cmd.CombinedOutput()
	if err != nil {
	return fmt.Errorf("%v\n%v", err, string(out))
	}
	return nil
	}

	// gatherExamples scans the HTML node and its children for blocks that contain
	// WGSL example code, populating the examples slice.
	func gatherExamples(node html.Node, examples []example) error {
	if hasClass(node, "example") && hasClass(node, "wgsl") {
	e := example{
	name: nodeID(node),
	code: exampleCode(node),
	globalScope: hasClass(node, "global-scope"),
	functionScope: hasClass(node, "function-scope"),
	expectError: hasClass(node, "expect-error"),
	}
	// If the example is annotated with a scope, then it can be compiled.
	if e.globalScope \|\| e.functionScope {
	examples = append(examples, e)
	}
	}
	for child := node.FirstChild; child != nil; child = child.NextSibling {
	if err := gatherExamples(child, examples); err != nil {
	return err
	}
	}
	return nil
	}

	// exampleCode returns a string formed from all the TextNodes found in <pre>
	// blocks that are children of node.
	func exampleCode(node *html.Node) string {
	sb := strings.Builder{}
	for child := node.FirstChild; child != nil; child = child.NextSibling {
	if child.Data == "pre" {
	printNodeText(child, &sb)
	}
	}
	return sb.String()
	}

	// printNodeText traverses node and its children, writing the Data of all
	// TextNodes to sb.
	func printNodeText(node html.Node, sb strings.Builder) {
	if node.Type == html.TextNode {
	sb.WriteString(node.Data)
	}

	for child := node.FirstChild; child != nil; child = child.NextSibling {
	printNodeText(child, sb)
	}
	}

	// hasClass returns true iff node is has the given "class" attribute.
	func hasClass(node *html.Node, class string) bool {
	for _, attr := range node.Attr {
	if attr.Key == "class" {
	classes := strings.Split(attr.Val, " ")
	for _, c := range classes {
	if c == class {
	return true
	}
	}
	}
	}
	return false
	}

	// nodeID returns the given "id" attribute of node, or an empty string if there
	// is no "id" attribute.
	func nodeID(node *html.Node) string {
	for _, attr := range node.Attr {
	if attr.Key == "id" {
	return attr.Val
	}
	}
	return ""
	}