1 files changed, 92 insertions, 0 deletions
diff --git a/src/codegen/internal-module-registry-scanner.ts b/src/codegen/internal-module-registry-scanner.ts
new file mode 100644
index 000000000..7bc2f9bdd
--- /dev/null
+++ b/src/codegen/internal-module-registry-scanner.ts
@@ -0,0 +1,92 @@
+import fs from "fs";
+import path from "path";
+import { readdirRecursive, resolveSyncOrNull } from "./helpers";
+
+export function createInternalModuleRegistry(basedir: string) {
+  const moduleList = ["bun", "node", "thirdparty", "internal"]
+    .flatMap(dir => readdirRecursive(path.join(basedir, dir)))
+    .filter(file => file.endsWith(".js") || (file.endsWith(".ts") && !file.endsWith(".d.ts")))
+    .map(file => file.slice(basedir.length + 1))
+    .sort();
+
+  // Create the Internal Module Registry
+  const internalRegistry = new Map();
+  for (let i = 0; i < moduleList.length; i++) {
+    const prefix = moduleList[i].startsWith("node/")
+      ? "node:"
+      : moduleList[i].startsWith("bun:")
+      ? "bun:"
+      : moduleList[i].startsWith("internal/")
+      ? "internal/"
+      : undefined;
+    if (prefix) {
+      const id = prefix + moduleList[i].slice(prefix.length).replaceAll(".", "/").slice(0, -3);
+      internalRegistry.set(id, i);
+    }
+  }
+
+  // Native Module registry
+  const nativeModuleH = fs.readFileSync(path.join(basedir, "../bun.js/modules/_NativeModule.h"), "utf8");
+  const nativeModuleDefine = nativeModuleH.match(/BUN_FOREACH_NATIVE_MODULE\(macro\)\s*\\\n((.*\\\n)*\n)/);
+  if (!nativeModuleDefine) {
+    throw new Error(
+      "Could not find BUN_FOREACH_NATIVE_MODULE in _NativeModule.h. Knowing native module IDs is a part of the codegen process.",
+    );
+  }
+  let nextNativeModuleId = 0;
+  const nativeModuleIds: Record<string, number> = {};
+  const nativeModuleEnums: Record<string, string> = {};
+  const nativeModuleEnumToId: Record<string, number> = {};
+  for (const [_, idString, enumValue] of nativeModuleDefine[0].matchAll(/macro\((.*?),(.*?)\)/g)) {
+    const processedIdString = JSON.parse(idString.trim().replace(/_s$/, ""));
+    const processedEnumValue = enumValue.trim();
+    const processedNumericId = nextNativeModuleId++;
+    nativeModuleIds[processedIdString] = processedNumericId;
+    nativeModuleEnums[processedIdString] = processedEnumValue;
+    nativeModuleEnumToId[processedEnumValue] = processedNumericId;
+  }
+
+  function codegenRequireId(id: string) {
+    return `(__intrinsic__getInternalField(__intrinsic__internalModuleRegistry, ${id}) || __intrinsic__createInternalModuleById(${id}))`;
+  }
+
+  function codegenRequireNativeModule(id: string) {
+    return `(__intrinsic__requireNativeModule(${id.replace(/node:/, "")}))`;
+  }
+
+  const requireTransformer = (specifier: string, from: string) => {
+    // this one is deprecated
+    if (specifier === "$shared") specifier = "./internal/shared.ts";
+
+    const directMatch = internalRegistry.get(specifier);
+    if (directMatch) return codegenRequireId(`${directMatch}/*${specifier}*/`);
+
+    if (specifier in nativeModuleIds) {
+      return codegenRequireNativeModule(JSON.stringify(specifier));
+    }
+
+    const relativeMatch =
+      resolveSyncOrNull(specifier, path.join(basedir, path.dirname(from))) ?? resolveSyncOrNull(specifier, basedir);
+
+    if (relativeMatch) {
+      const found = moduleList.indexOf(path.relative(basedir, relativeMatch));
+      if (found === -1) {
+        throw new Error(
+          `Builtin Bundler: "${specifier}" cannot be imported here because it doesn't get a module ID. Only files in "src/js" besides "src/js/builtins" can be used here. Note that the 'node:' or 'bun:' prefix is required here. `,
+        );
+      }
+      return codegenRequireId(`${found}/*${path.relative(basedir, relativeMatch)}*/`);
+    }
+
+    throw new Error(`Builtin Bundler: Could not resolve "${specifier}" in ${from}.`);
+  };
+
+  return {
+    requireTransformer,
+    nativeModuleIds,
+    nativeModuleEnums,
+    nativeModuleEnumToId,
+    internalRegistry,
+    moduleList,
+  } as const;
+}