wip: wasm build

d2js/README.md

@@ -0,0 +1,30 @@
+# D2 as a Javascript library
+
+D2 is runnable as a Javascript library, on both the client and server side. This means you
+can run D2 entirely on the browser.
+
+This is achieved by a JS wrapper around a WASM file.
+
+## Install
+
+### NPM
+
+```sh
+npm install @terrastruct/d2
+```
+
+### Yarn
+
+```sh
+yarn add @terrastruct/d2
+```
+
+## Build
+
+```sh
+GOOS=js GOARCH=wasm go build -ldflags='-s -w' -trimpath -o main.wasm ./d2js
+```
+
+## API
+
+todo

d2js/js.go

@@ -0,0 +1,333 @@
+//go:build wasm
+
+package main
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"io/fs"
+	"os"
+	"strings"
+	"syscall/js"
+
+	"oss.terrastruct.com/d2/d2ast"
+	"oss.terrastruct.com/d2/d2compiler"
+	"oss.terrastruct.com/d2/d2format"
+	"oss.terrastruct.com/d2/d2lsp"
+	"oss.terrastruct.com/d2/d2oracle"
+	"oss.terrastruct.com/d2/d2parser"
+	"oss.terrastruct.com/d2/lib/urlenc"
+	"oss.terrastruct.com/d2/lib/version"
+)
+
+func main() {
+	js.Global().Set("d2GetParentID", js.FuncOf(jsGetParentID))
+	js.Global().Set("d2GetObjOrder", js.FuncOf(jsGetObjOrder))
+	js.Global().Set("d2GetRefRanges", js.FuncOf(jsGetRefRanges))
+	js.Global().Set("d2Compile", js.FuncOf(jsCompile))
+	js.Global().Set("d2GetBoardAtPosition", js.FuncOf(jsGetBoardAtPosition))
+	js.Global().Set("d2Parse", js.FuncOf(jsParse))
+	js.Global().Set("d2Encode", js.FuncOf(jsEncode))
+	js.Global().Set("d2Decode", js.FuncOf(jsDecode))
+	js.Global().Set("d2Version", js.FuncOf(jsVersion))
+	initCallback := js.Global().Get("onWasmInitialized")
+	if !initCallback.IsUndefined() {
+		initCallback.Invoke()
+	}
+	select {}
+}
+
+type jsObjOrder struct {
+	Order []string `json:"order"`
+	Error string   `json:"error"`
+}
+
+func jsGetObjOrder(this js.Value, args []js.Value) interface{} {
+	dsl := args[0].String()
+
+	g, _, err := d2compiler.Compile("", strings.NewReader(dsl), &d2compiler.CompileOptions{
+		UTF16Pos: true,
+	})
+	if err != nil {
+		ret := jsObjOrder{Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	objOrder, err := d2oracle.GetObjOrder(g, nil)
+	if err != nil {
+		ret := jsObjOrder{Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+	resp := jsObjOrder{
+		Order: objOrder,
+	}
+
+	str, _ := json.Marshal(resp)
+	return string(str)
+}
+
+func jsGetParentID(this js.Value, args []js.Value) interface{} {
+	id := args[0].String()
+
+	mk, _ := d2parser.ParseMapKey(id)
+
+	if len(mk.Edges) > 0 {
+		return ""
+	}
+
+	if mk.Key != nil {
+		if len(mk.Key.Path) == 1 {
+			return "root"
+		}
+		mk.Key.Path = mk.Key.Path[:len(mk.Key.Path)-1]
+		return strings.Join(mk.Key.IDA(), ".")
+	}
+
+	return ""
+}
+
+type jsRefRanges struct {
+	Ranges       []d2ast.Range `json:"ranges"`
+	ImportRanges []d2ast.Range `json:"importRanges"`
+	ParseError   string        `json:"parseError"`
+	UserError    string        `json:"userError"`
+	D2Error      string        `json:"d2Error"`
+}
+
+func jsGetRefRanges(this js.Value, args []js.Value) interface{} {
+	fsRaw := args[0].String()
+	file := args[1].String()
+	key := args[2].String()
+	boardPathRaw := args[3].String()
+
+	var fs map[string]string
+	err := json.Unmarshal([]byte(fsRaw), &fs)
+	if err != nil {
+		ret := jsRefRanges{D2Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	_, err = d2parser.ParseMapKey(key)
+	if err != nil {
+		ret := jsRefRanges{D2Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	var boardPath []string
+	err = json.Unmarshal([]byte(boardPathRaw), &boardPath)
+	if err != nil {
+		ret := jsRefRanges{D2Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	ranges, importRanges, err := d2lsp.GetRefRanges(file, fs, boardPath, key)
+	if err != nil {
+		ret := jsRefRanges{D2Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	resp := jsRefRanges{
+		Ranges:       ranges,
+		ImportRanges: importRanges,
+	}
+
+	str, _ := json.Marshal(resp)
+	return string(str)
+}
+
+type jsObject struct {
+	Result    string `json:"result"`
+	UserError string `json:"userError"`
+	D2Error   string `json:"d2Error"`
+}
+
+type jsParseResponse struct {
+	DSL        string `json:"dsl"`
+	ParseError string `json:"parseError"`
+	UserError  string `json:"userError"`
+	D2Error    string `json:"d2Error"`
+}
+
+type emptyFile struct{}
+
+func (f *emptyFile) Stat() (os.FileInfo, error) {
+	return nil, nil
+}
+
+func (f *emptyFile) Read(p []byte) (int, error) {
+	return 0, io.EOF
+}
+
+func (f *emptyFile) Close() error {
+	return nil
+}
+
+type detectFS struct {
+	importUsed bool
+}
+
+func (detectFS *detectFS) Open(name string) (fs.File, error) {
+	detectFS.importUsed = true
+	return &emptyFile{}, nil
+}
+
+func jsParse(this js.Value, args []js.Value) interface{} {
+	dsl := args[0].String()
+	themeID := args[1].Int()
+
+	detectFS := detectFS{}
+
+	g, _, err := d2compiler.Compile("", strings.NewReader(dsl), &d2compiler.CompileOptions{
+		UTF16Pos: true,
+		FS:       &detectFS,
+	})
+	// If an import was used, client side D2 cannot reliably compile
+	// Defer to backend compilation
+	if !detectFS.importUsed {
+		var pe *d2parser.ParseError
+		if err != nil {
+			if errors.As(err, &pe) {
+				serialized, _ := json.Marshal(err)
+				ret := jsParseResponse{ParseError: string(serialized)}
+				str, _ := json.Marshal(ret)
+				return string(str)
+			}
+			ret := jsParseResponse{D2Error: err.Error()}
+			str, _ := json.Marshal(ret)
+			return string(str)
+		}
+
+		for _, o := range g.Objects {
+			if (o.Attributes.Top == nil) != (o.Attributes.Left == nil) {
+				ret := jsParseResponse{UserError: `keywords "top" and "left" currently must be used together`}
+				str, _ := json.Marshal(ret)
+				return string(str)
+			}
+		}
+
+		err = g.ApplyTheme(int64(themeID))
+		if err != nil {
+			ret := jsParseResponse{D2Error: err.Error()}
+			str, _ := json.Marshal(ret)
+			return string(str)
+		}
+	}
+
+	m, err := d2parser.Parse("", strings.NewReader(dsl), &d2parser.ParseOptions{
+		UTF16Pos: true,
+	})
+	if err != nil {
+		return err
+	}
+
+	resp := jsParseResponse{}
+
+	newDSL := d2format.Format(m)
+	if dsl != newDSL {
+		resp.DSL = newDSL
+	}
+
+	str, _ := json.Marshal(resp)
+	return string(str)
+}
+
+// TODO error passing
+// TODO recover panics
+func jsCompile(this js.Value, args []js.Value) interface{} {
+	script := args[0].String()
+
+	g, _, err := d2compiler.Compile("", strings.NewReader(script), &d2compiler.CompileOptions{
+		UTF16Pos: true,
+	})
+	var pe *d2parser.ParseError
+	if err != nil {
+		if errors.As(err, &pe) {
+			serialized, _ := json.Marshal(err)
+			ret := jsObject{UserError: string(serialized)}
+			str, _ := json.Marshal(ret)
+			return string(str)
+		}
+		ret := jsObject{D2Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	newScript := d2format.Format(g.AST)
+	if script != newScript {
+		ret := jsObject{Result: newScript}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	return nil
+}
+
+func jsEncode(this js.Value, args []js.Value) interface{} {
+	script := args[0].String()
+
+	encoded, err := urlenc.Encode(script)
+	// should never happen
+	if err != nil {
+		ret := jsObject{D2Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	ret := jsObject{Result: encoded}
+	str, _ := json.Marshal(ret)
+	return string(str)
+}
+
+func jsDecode(this js.Value, args []js.Value) interface{} {
+	script := args[0].String()
+
+	script, err := urlenc.Decode(script)
+	if err != nil {
+		ret := jsObject{UserError: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	ret := jsObject{Result: script}
+	str, _ := json.Marshal(ret)
+	return string(str)
+}
+
+func jsVersion(this js.Value, args []js.Value) interface{} {
+	return version.Version
+}
+
+type jsBoardAtPosition struct {
+	BoardPath []string `json:"boardPath"`
+	Error     string   `json:"error"`
+}
+
+func jsGetBoardAtPosition(this js.Value, args []js.Value) interface{} {
+	dsl := args[0].String()
+	line := args[1].Int()
+	column := args[2].Int()
+
+	boardPath, err := d2lsp.GetBoardAtPosition(dsl, d2ast.Position{
+		Line:   line,
+		Column: column,
+	})
+
+	if err != nil {
+		ret := jsBoardAtPosition{Error: err.Error()}
+		str, _ := json.Marshal(ret)
+		return string(str)
+	}
+
+	resp := jsBoardAtPosition{
+		BoardPath: boardPath,
+	}
+	str, _ := json.Marshal(resp)
+	return string(str)
+}

d2renderers/d2latex/latex.go

@@ -1,3 +1,5 @@
+//go:build !wasm
+
 package d2latex
 
 import (

d2renderers/d2latex/latex_stub.go

@@ -0,0 +1,11 @@
+//go:build wasm
+
+package d2latex
+
+func Render(s string) (_ string, err error) {
+	return "", nil
+}
+
+func Measure(s string) (width, height int, err error) {
+	return
+}

lib/textmeasure/markdown.go

@@ -1,3 +1,5 @@
+//go:build !wasm
+
 package textmeasure
 
 import (