Move the ImportResolver to Args

Closes #2

README.md

@@ -1,5 +1,3 @@
-**Note** that this repository will probably be archived if I cannot find a solution to [this blocking issue](https://github.com/bep/godartsass/issues/2).
-
 [![Tests on Linux, MacOS and Windows](https://github.com/bep/godartsass/workflows/Test/badge.svg)](https://github.com/bep/godartsass/actions?query=workflow%3ATest)
 [![Go Report Card](https://goreportcard.com/badge/github.com/bep/godartsass)](https://goreportcard.com/report/github.com/bep/godartsass)
 [![codecov](https://codecov.io/gh/bep/godartsass/branch/main/graph/badge.svg?token=OWZ9RCAYWO)](https://codecov.io/gh/bep/godartsass)

go.mod

@@ -5,7 +5,5 @@ go 1.15
 require (
 	github.com/cli/safeexec v1.0.0
 	github.com/frankban/quicktest v1.11.2
-	github.com/google/go-cmp v0.5.2
-	github.com/sanity-io/litter v1.3.0
 	google.golang.org/protobuf v1.25.0
 )

go.sum

@@ -4,8 +4,6 @@ github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA
 github.com/cli/safeexec v1.0.0 h1:0VngyaIyqACHdcMNWfo6+KdUYnqEr2Sg+bSP1pdF+dI=
 github.com/cli/safeexec v1.0.0/go.mod h1:Z/D4tTN8Vs5gXYHDCbaM1S/anmEDnJb1iW0+EJ5zx3Q=
 github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
-github.com/davecgh/go-spew v0.0.0-20161028175848-04cdfd42973b h1:XxMZvQZtTXpWMNWK82vdjCLCe7uGMFXdTsJH0v3Hkvw=
-github.com/davecgh/go-spew v0.0.0-20161028175848-04cdfd42973b/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/envoyproxy/go-control-plane v0.9.1-0.20191026205805-5f8ba28d4473/go.mod h1:YTl/9mNaCwkRvm6d1a2C3ymFceY/DCBVvsKhRF0iEA4=
 github.com/envoyproxy/protoc-gen-validate v0.1.0/go.mod h1:iSmxcyjqTsJpI2R4NaDN7+kN2VEUnK/pcBlmesArF7c=
 github.com/frankban/quicktest v1.11.2 h1:mjwHjStlXWibxOohM7HYieIViKyh56mmt3+6viyhDDI=
@@ -33,13 +31,7 @@ github.com/kr/pretty v0.2.1/go.mod h1:ipq/a2n7PKx3OHsz4KJII5eveXtPO4qwEXGdVfWzfn
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/pmezard/go-difflib v0.0.0-20151028094244-d8ed2627bdf0 h1:GD+A8+e+wFkqje55/2fOVnZPkoDIu1VooBWfNrnY8Uo=
-github.com/pmezard/go-difflib v0.0.0-20151028094244-d8ed2627bdf0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_model v0.0.0-20190812154241-14fe0d1b01d4/go.mod h1:xMI15A0UPsDsEKsMN9yxemIoYk6Tm2C1GtYGdfGttqA=
-github.com/sanity-io/litter v1.3.0 h1:5ZO+weUsqdSWMUng5JnpkW/Oz8iTXiIdeumhQr1sSjs=
-github.com/sanity-io/litter v1.3.0/go.mod h1:5Z71SvaYy5kcGtyglXOC9rrUi3c1E8CamFWjQsazTh0=
-github.com/stretchr/testify v0.0.0-20161117074351-18a02ba4a312 h1:UsFdQ3ZmlzS0BqZYGxvYaXvFGUbCmPGy8DM7qWJJiIQ=
-github.com/stretchr/testify v0.0.0-20161117074351-18a02ba4a312/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/exp v0.0.0-20190121172915-509febef88a4/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/lint v0.0.0-20181026193005-c67002cb31c3/go.mod h1:UVdnD1Gm6xHRNCYTkRU2/jEulfH38KcIWyp/GAMgvoE=

options.go

@@ -17,9 +17,6 @@ type Options struct {
 	// There may be several ways to install this, one would be to
 	// download it from here: https://github.com/sass/dart-sass-embedded/releases
 	DartSassEmbeddedFilename string
-
-	// Custom resolver to use to resolve imports.
-	ImportResolver ImportResolver
 }
 
 func (opts *Options) init() error {
@@ -68,6 +65,10 @@ type Args struct {
 	// If enabled, a sourcemap will be generated and returned in Result.
 	EnableSourceMap bool
 
+	// Custom resolver to use to resolve imports.
+	// If set, this will be the first in the resolver chain.
+	ImportResolver ImportResolver
+
 	// Additional file paths to uses to resolve imports.
 	IncludePaths []string
 
@@ -78,7 +79,7 @@ type Args struct {
 	sassImporters []*embeddedsass.InboundMessage_CompileRequest_Importer
 }
 
-func (args *Args) init(opts Options) error {
+func (args *Args) init(seq uint32, opts Options) error {
 	if args.OutputStyle == "" {
 		args.OutputStyle = OutputStyleNested
 	}
@@ -99,11 +100,11 @@ func (args *Args) init(opts Options) error {
 
 	args.sassSourceSyntax = embeddedsass.InboundMessage_Syntax(v)
 
-	if opts.ImportResolver != nil {
+	if args.ImportResolver != nil {
 		args.sassImporters = []*embeddedsass.InboundMessage_CompileRequest_Importer{
 			{
 				Importer: &embeddedsass.InboundMessage_CompileRequest_Importer_ImporterId{
-					ImporterId: importerID,
+					ImporterId: seq,
 				},
 			},
 		}

transpiler.go

@@ -21,12 +21,6 @@ import (
 
 var defaultDartSassEmbeddedFilename = "dart-sass-embedded"
 
-const (
-
-	// There is only one, and this number is picked out of a hat.
-	importerID = 5679
-)
-
 // Start creates an starts a new SCSS transpiler that communicates with the
 // Dass Sass Embedded protocol via Stdin and Stdout.
 //
@@ -75,8 +69,8 @@ type Transpiler struct {
 	// stdin/stdout of the Dart Sass protocol
 	conn io.ReadWriteCloser
 
-	// Protects the sending of the compile request.
-	reqMu sync.Mutex
+	// Protects the sending of messages to Dart Sass.
+	sendMu sync.Mutex
 
 	mu      sync.Mutex // Protects all below.
 	seq     uint32
@@ -122,35 +116,42 @@ func (t *Transpiler) Close() error {
 func (t *Transpiler) Execute(args Args) (Result, error) {
 	var result Result
 
-	if err := args.init(t.opts); err != nil {
-		return result, err
-	}
+	createInboundMessage := func(seq uint32) (*embeddedsass.InboundMessage, error) {
+		if err := args.init(seq, t.opts); err != nil {
+			return nil, err
+		}
 
-	message := &embeddedsass.InboundMessage_CompileRequest_{
-		CompileRequest: &embeddedsass.InboundMessage_CompileRequest{
-			Importers: args.sassImporters,
-			Style:     args.sassOutputStyle,
-			Input: &embeddedsass.InboundMessage_CompileRequest_String_{
-				String_: &embeddedsass.InboundMessage_CompileRequest_StringInput{
-					Syntax: args.sassSourceSyntax,
-					Source: args.Source,
-					Url:    args.URL,
+		message := &embeddedsass.InboundMessage_CompileRequest_{
+			CompileRequest: &embeddedsass.InboundMessage_CompileRequest{
+				Importers: args.sassImporters,
+				Style:     args.sassOutputStyle,
+				Input: &embeddedsass.InboundMessage_CompileRequest_String_{
+					String_: &embeddedsass.InboundMessage_CompileRequest_StringInput{
+						Syntax: args.sassSourceSyntax,
+						Source: args.Source,
+						Url:    args.URL,
+					},
 				},
+				SourceMap: args.EnableSourceMap,
 			},
-			SourceMap: args.EnableSourceMap,
-		},
-	}
+		}
 
-	resp, err := t.invoke(
-		&embeddedsass.InboundMessage{
+		return &embeddedsass.InboundMessage{
 			Message: message,
-		},
-	)
+		}, nil
+	}
+
+	call, err := t.newCall(createInboundMessage, args)
 	if err != nil {
 		return result, err
 	}
+	call = <-call.Done
+	if call.Error != nil {
+		return result, call.Error
+	}
 
-	csp := resp.Message.(*embeddedsass.OutboundMessage_CompileResponse_)
+	response := call.Response
+	csp := response.Message.(*embeddedsass.OutboundMessage_CompileResponse_)
 
 	switch resp := csp.CompileResponse.Result.(type) {
 	case *embeddedsass.OutboundMessage_CompileResponse_Success:
@@ -174,6 +175,16 @@ func (t *Transpiler) Execute(args Args) (Result, error) {
 	return result, nil
 }
 
+func (t *Transpiler) getImportResolver(id uint32) ImportResolver {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+	call, found := t.pending[id]
+	if !found {
+		panic(fmt.Sprintf("call with ID %d not found", id))
+	}
+	return call.importResolver
+}
+
 func (t *Transpiler) input() {
 	var err error
 
@@ -214,13 +225,13 @@ func (t *Transpiler) input() {
 			call.Response = &msg
 			call.done()
 		case *embeddedsass.OutboundMessage_CanonicalizeRequest_:
+			resolver := t.getImportResolver(c.CanonicalizeRequest.CompilationId)
 			var url *embeddedsass.InboundMessage_CanonicalizeResponse_Url
-			if resolved := t.opts.ImportResolver.CanonicalizeURL(c.CanonicalizeRequest.GetUrl()); resolved != "" {
+			if resolved := resolver.CanonicalizeURL(c.CanonicalizeRequest.GetUrl()); resolved != "" {
 				url = &embeddedsass.InboundMessage_CanonicalizeResponse_Url{
 					Url: resolved,
 				}
 			}
-
 			response := &embeddedsass.InboundMessage_CanonicalizeResponse_{
 				CanonicalizeResponse: &embeddedsass.InboundMessage_CanonicalizeResponse{
 					Id:     c.CanonicalizeRequest.GetId(),
@@ -235,6 +246,7 @@ func (t *Transpiler) input() {
 			)
 
 		case *embeddedsass.OutboundMessage_ImportRequest_:
+			resolver := t.getImportResolver(c.ImportRequest.CompilationId)
 			url := c.ImportRequest.GetUrl()
 			var sourceMapURL string
 			// Dart Sass expect a browser-accessible URL or an empty string.
@@ -251,7 +263,7 @@ func (t *Transpiler) input() {
 					Id: c.ImportRequest.GetId(),
 					Result: &embeddedsass.InboundMessage_ImportResponse_Success{
 						Success: &embeddedsass.InboundMessage_ImportResponse_ImportSuccess{
-							Contents:     t.opts.ImportResolver.Load(url),
+							Contents:     resolver.Load(url),
 							SourceMapUrl: sourceMapURL,
 						},
 					},
@@ -279,28 +291,22 @@ func (t *Transpiler) input() {
 	}
 }
 
-func (t *Transpiler) invoke(message *embeddedsass.InboundMessage) (*embeddedsass.OutboundMessage, error) {
-	request := &call{
-		Request: message,
-		Done:    make(chan *call, 1),
+func (t *Transpiler) newCall(createInbound func(seq uint32) (*embeddedsass.InboundMessage, error), args Args) (*call, error) {
+	t.mu.Lock()
+	// TODO1 handle shutdown.
+	id := t.seq
+	req, err := createInbound(id)
+	if err != nil {
+		t.mu.Unlock()
+		return nil, err
 	}
 
-	response := <-t.sendCall(request).Done
-
-	if response.Error != nil {
-		return nil, response.Error
+	call := &call{
+		Request:        req,
+		Done:           make(chan *call, 1),
+		importResolver: args.ImportResolver,
 	}
 
-	return response.Response, nil
-}
-
-func (t *Transpiler) sendCall(call *call) *call {
-	t.reqMu.Lock()
-	defer t.reqMu.Unlock()
-
-	t.mu.Lock()
-	// TODO1 handle shutdown.
-	id := t.seq
 	t.pending[id] = call
 	t.seq++
 	t.mu.Unlock()
@@ -309,16 +315,16 @@ func (t *Transpiler) sendCall(call *call) *call {
 	case *embeddedsass.InboundMessage_CompileRequest_:
 		c.CompileRequest.Id = id
 	default:
-		call.Error = fmt.Errorf("unsupported request message type. %T", call.Request.Message)
-		return call
+		return nil, fmt.Errorf("unsupported request message type. %T", call.Request.Message)
 	}
 
-	call.Error = t.sendInboundMessage(call.Request)
-
-	return call
+	return call, t.sendInboundMessage(call.Request)
 }
 
 func (t *Transpiler) sendInboundMessage(message *embeddedsass.InboundMessage) error {
+	t.sendMu.Lock()
+	defer t.sendMu.Unlock()
+
 	out, err := proto.Marshal(message)
 	if err != nil {
 		return fmt.Errorf("failed to marshal request: %s", err)
@@ -340,8 +346,9 @@ func (t *Transpiler) sendInboundMessage(message *embeddedsass.InboundMessage) er
 }
 
 type call struct {
-	Request  *embeddedsass.InboundMessage
-	Response *embeddedsass.OutboundMessage
+	Request        *embeddedsass.InboundMessage
+	Response       *embeddedsass.OutboundMessage
+	importResolver ImportResolver
 
 	Error error
 	Done  chan *call

transpiler_test.go

@@ -42,7 +42,7 @@ func (t testImportResolver) CanonicalizeURL(url string) string {
 		return ""
 	}
 
-	return "file:/myproject/scss/" + url + "_myfile.scss"
+	return "file:/my" + t.name + "/scss/" + url + "_myfile.scss"
 }
 
 func (t testImportResolver) Load(url string) string {
@@ -79,8 +79,7 @@ body
 			OutputStyle:  OutputStyleCompressed,
 			SourceSyntax: SourceSyntaxSASS,
 		}, Result{CSS: "body{font:100% Helvetica,sans-serif;color:#333}"}},
-		{"Import resolver", Options{ImportResolver: colorsResolver}, Args{Source: "@import \"colors\";\ndiv { p { color: $white; } }"}, Result{CSS: "div p {\n  color: #ffff;\n}"}},
-		{"Import resolver with source map", Options{ImportResolver: colorsResolver}, Args{Source: "@import \"colors\";\ndiv { p { color: $white; } }", EnableSourceMap: true}, Result{CSS: "div p {\n  color: #ffff;\n}", SourceMap: "{\"version\":3,\"sourceRoot\":\"\",\"sources\":[\"data:;charset=utf-8,@import%20%22colors%22;%0Adiv%20%7B%20p%20%7B%20color:%20$white;%20%7D%20%7D\",\"file:///myproject/scss/colors_myfile.scss\"],\"names\":[],\"mappings\":\"AACM;EAAI,OCDC\"}"}},
+		{"Import resolver with source map", Options{}, Args{Source: "@import \"colors\";\ndiv { p { color: $white; } }", EnableSourceMap: true, ImportResolver: colorsResolver}, Result{CSS: "div p {\n  color: #ffff;\n}", SourceMap: "{\"version\":3,\"sourceRoot\":\"\",\"sources\":[\"data:;charset=utf-8,@import%20%22colors%22;%0Adiv%20%7B%20p%20%7B%20color:%20$white;%20%7D%20%7D\",\"file:///mycolors/scss/colors_myfile.scss\"],\"names\":[],\"mappings\":\"AACM;EAAI,OCDC\"}"}},
 
 		// Error cases
 		{"Invalid syntax", Options{}, Args{Source: "div { color: $white; }"}, false},
@@ -179,6 +178,55 @@ div { color: $primary-color; }`, num)
 	wg.Wait()
 }
 
+func TestTranspilerParallelImportResolver(t *testing.T) {
+	c := qt.New(t)
+
+	createImportResolver := func(width int) ImportResolver {
+
+		return testImportResolver{
+			name:    "widths",
+			content: fmt.Sprintf(`$width:  %d`, width),
+		}
+
+	}
+
+	transpiler, clean := newTestTranspiler(c, Options{})
+	defer clean()
+
+	var wg sync.WaitGroup
+
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func(i int) {
+			defer wg.Done()
+
+			for j := 0; j < 10; j++ {
+
+				for k := 0; k < 20; k++ {
+					args := Args{
+						OutputStyle:    OutputStyleCompressed,
+						ImportResolver: createImportResolver(j + i),
+						Source: `
+@import "widths";
+
+div { p { width: $width; } }`,
+					}
+
+					result, err := transpiler.Execute(args)
+					c.Check(err, qt.IsNil)
+					c.Check(result.CSS, qt.Equals, fmt.Sprintf("div p{width:%d}", j+i))
+					if c.Failed() {
+						return
+					}
+				}
+			}
+		}(i)
+	}
+
+	wg.Wait()
+
+}
+
 func BenchmarkTranspiler(b *testing.B) {
 	type tester struct {
 		src        string