avoid temporary .ts file due to lack of sandbox on Windows

Just a quick hack for now to store it in memory, as the temp file
conflicts on Windows due to the lack of a sandbox, and we don't really
have a need to write it to the filesystem anyway.

ts/svelte/svelte.bzl

@@ -6,18 +6,15 @@ def _svelte(ctx):
     args.use_param_file("@%s", use_always = True)
     args.set_param_file_format("multiline")
 
-    temp_ts_path = ctx.actions.declare_file(ctx.attr.name + ".svelte.ts")
-
     args.add(ctx.file.entry_point.path)
     args.add(ctx.outputs.mjs.path)
     args.add(ctx.outputs.dts.path)
-    args.add(temp_ts_path)
     args.add_all(ctx.files._shims)
 
     ctx.actions.run(
         execution_requirements = {"supports-workers": "1"},
         executable = ctx.executable._svelte_bin,
-        outputs = [ctx.outputs.mjs, ctx.outputs.dts, temp_ts_path],
+        outputs = [ctx.outputs.mjs, ctx.outputs.dts],
         inputs = [ctx.file.entry_point] + ctx.files._shims,
         mnemonic = "Svelte",
         arguments = [args],

ts/svelte/svelte.ts

@@ -16,24 +16,38 @@ let parsedCommandLine: ts.ParsedCommandLine = {
     },
 };
 
+let tsText = "";
+
 // largely taken from https://github.com/Asana/bazeltsc/blob/7dfa0ba2bd5eb9ee556e146df35cf793fad2d2c3/src/bazeltsc.ts (MIT)
 const languageServiceHost: ts.LanguageServiceHost = {
     getCompilationSettings: (): ts.CompilerOptions => parsedCommandLine.options,
     getNewLine: () => ts.sys.newLine,
     getScriptFileNames: (): string[] => parsedCommandLine.fileNames,
     getScriptVersion: (fileName: string): string => {
+        if (fileName == parsedCommandLine.fileNames[0]) {
+            return require("crypto").createHash("md5").update(tsText).digest("hex");
+        } else {
             // If the file's size or modified-timestamp changed, it's a different version.
             return (
                 ts.sys.getFileSize!(fileName) +
                 ":" +
                 ts.sys.getModifiedTime!(fileName)!.getTime()
             );
+        }
     },
     getScriptSnapshot: (fileName: string): ts.IScriptSnapshot | undefined => {
+        let text;
+        if (fileName == parsedCommandLine.fileNames[0]) {
+            // serve out generated ts file from memory, so we can avoid writing a temporary
+            // file that causes conflicts on Windows
+            text = tsText;
+        } else {
             if (!ts.sys.fileExists(fileName)) {
                 return undefined;
+            } else {
+                text = ts.sys.readFile(fileName)!;
+            }
         }
-        let text = ts.sys.readFile(fileName)!;
         return {
             getText: (start: number, end: number) => {
                 if (start === 0 && end === text.length) {
@@ -129,7 +143,7 @@ async function writeDts(tsPath, dtsPath, shims) {
     await writeFile(dtsPath, dtsSource);
 }
 
-async function writeTs(svelteSource, sveltePath, tsPath) {
+function writeTs(svelteSource, sveltePath) {
     let tsSource = svelte2tsx(svelteSource, {
         filename: sveltePath,
         strictMode: true,
@@ -139,7 +153,8 @@ async function writeTs(svelteSource, sveltePath, tsPath) {
     // replace the "///<reference types="svelte" />" with a line
     // turning off checking, as we'll use svelte-check for that
     codeLines[0] = "// @ts-nocheck";
-    await writeFile(tsPath, codeLines.join("\n"));
+    // write to our global
+    tsText = codeLines.join("\n");
 }
 
 async function writeJs(source, inputFilename, outputPath) {
@@ -167,10 +182,13 @@ async function writeJs(source, inputFilename, outputPath) {
 }
 
 async function compileSvelte(args) {
-    const [sveltePath, mjsPath, dtsPath, tempTsPath, ...shims] = args;
+    const [sveltePath, mjsPath, dtsPath, ...shims] = args;
     const svelteSource = await readFile(sveltePath);
 
-    await writeTs(svelteSource, sveltePath, tempTsPath);
+    // mock filename
+    const tempTsPath = sveltePath + ".ts";
+
+    await writeTs(svelteSource, sveltePath);
     await writeDts(tempTsPath, dtsPath, shims);
     await writeJs(svelteSource, sveltePath, mjsPath);