src: share common code paths for SEA and embedder script

lib/internal/main/embedding.js

@@ -0,0 +1,18 @@
+'use strict';
+const {
+  prepareMainThreadExecution,
+  markBootstrapComplete,
+} = require('internal/process/pre_execution');
+const { isSea } = internalBinding('sea');
+const { emitExperimentalWarning } = require('internal/util');
+const { embedderRequire, embedderRunCjs } = require('internal/util/embedding');
+const { getEmbedderEntryFunction } = internalBinding('mksnapshot');
+
+prepareMainThreadExecution(false, true);
+markBootstrapComplete();
+
+if (isSea) {
+  emitExperimentalWarning('Single executable application');
+}
+
+return getEmbedderEntryFunction()(embedderRequire, embedderRunCjs);

lib/internal/main/mksnapshot.js

@@ -119,16 +119,25 @@ function main() {
   const {
     prepareMainThreadExecution
   } = require('internal/process/pre_execution');
+  const path = require('path');
 
   let serializeMainFunction = getEmbedderEntryFunction();
   const serializeMainArgs = [requireForUserSnapshot];
 
   if (serializeMainFunction) { // embedded case
     prepareMainThreadExecution(false, false);
+    // TODO(addaleax): Make this `embedderRunCjs` once require('module')
+    // is supported in snapshots.
+    const filename = process.execPath;
+    const dirname = path.dirname(filename);
+    function minimalRunCjs(source) {
+      const fn = compileSerializeMain(filename, source);
+      return fn(requireForUserSnapshot, filename, dirname);
+    }
+    serializeMainArgs.push(minimalRunCjs);
   } else {
     prepareMainThreadExecution(true, false);
     const file = process.argv[1];
-    const path = require('path');
     const filename = path.resolve(file);
     const dirname = path.dirname(filename);
     const source = readFileSync(file, 'utf-8');

lib/internal/util/embedding.js

@@ -0,0 +1,47 @@
+'use strict';
+const { codes: { ERR_UNKNOWN_BUILTIN_MODULE } } = require('internal/errors');
+const { Module, wrapSafe } = require('internal/modules/cjs/loader');
+
+// This is roughly the same as:
+//
+// const mod = new Module(filename);
+// mod._compile(contents, filename);
+//
+// but the code has been duplicated because currently there is no way to set the
+// value of require.main to module.
+//
+// TODO(RaisinTen): Find a way to deduplicate this.
+
+function embedderRunCjs(contents) {
+  const filename = process.execPath;
+  const compiledWrapper = wrapSafe(filename, contents);
+
+  const customModule = new Module(filename, null);
+  customModule.filename = filename;
+  customModule.paths = Module._nodeModulePaths(customModule.path);
+
+  const customExports = customModule.exports;
+
+  embedderRequire.main = customModule;
+
+  const customFilename = customModule.filename;
+
+  const customDirname = customModule.path;
+
+  return compiledWrapper(
+    customExports,
+    embedderRequire,
+    customModule,
+    customFilename,
+    customDirname);
+}
+
+function embedderRequire(path) {
+  if (!Module.isBuiltin(path)) {
+    throw new ERR_UNKNOWN_BUILTIN_MODULE(path);
+  }
+
+  return require(path);
+}
+
+module.exports = { embedderRequire, embedderRunCjs };

src/api/environment.cc

@@ -528,17 +528,15 @@ MaybeLocal<Value> LoadEnvironment(
   return StartExecution(env, cb);
 }
 
-MaybeLocal<Value> LoadEnvironment(
-    Environment* env,
-    const char* main_script_source_utf8) {
-  CHECK_NOT_NULL(main_script_source_utf8);
+MaybeLocal<Value> LoadEnvironment(Environment* env,
+                                  std::string_view main_script_source_utf8) {
+  CHECK_NOT_NULL(main_script_source_utf8.data());
   return LoadEnvironment(
       env, [&](const StartExecutionCallbackInfo& info) -> MaybeLocal<Value> {
-        std::string name = "embedder_main_" + std::to_string(env->thread_id());
-        env->builtin_loader()->Add(name.c_str(), main_script_source_utf8);
-        Realm* realm = env->principal_realm();
-
-        return realm->ExecuteBootstrapper(name.c_str());
+        Local<Value> main_script =
+            ToV8Value(env->context(), main_script_source_utf8).ToLocalChecked();
+        return info.run_cjs->Call(
+            env->context(), Null(env->isolate()), 1, &main_script);
       });
 }
 

src/node.cc

@@ -277,22 +277,17 @@ MaybeLocal<Value> StartExecution(Environment* env, StartExecutionCallback cb) {
 
   if (cb != nullptr) {
     EscapableHandleScope scope(env->isolate());
+    // TODO(addaleax): pass the callback to the main script more directly,
+    // e.g. by making StartExecution(env, builtin) parametrizable
+    env->set_embedder_mksnapshot_entry_point(std::move(cb));
+    auto reset_entry_point =
+        OnScopeLeave([&]() { env->set_embedder_mksnapshot_entry_point({}); });
 
-    if (env->isolate_data()->options()->build_snapshot) {
-      // TODO(addaleax): pass the callback to the main script more directly,
-      // e.g. by making StartExecution(env, builtin) parametrizable
-      env->set_embedder_mksnapshot_entry_point(std::move(cb));
-      auto reset_entry_point =
-          OnScopeLeave([&]() { env->set_embedder_mksnapshot_entry_point({}); });
+    const char* entry = env->isolate_data()->options()->build_snapshot
+                            ? "internal/main/mksnapshot"
+                            : "internal/main/embedding";
 
-      return StartExecution(env, "internal/main/mksnapshot");
-    }
-
-    if (StartExecution(env, "internal/main/environment").IsEmpty()) return {};
-    return scope.EscapeMaybe(cb({
-        env->process_object(),
-        env->builtin_module_require(),
-    }));
+    return scope.EscapeMaybe(StartExecution(env, entry));
   }
 
   // TODO(joyeecheung): move these conditions into JS land and let the
@@ -312,18 +307,6 @@ MaybeLocal<Value> StartExecution(Environment* env, StartExecutionCallback cb) {
     first_argv = env->argv()[1];
   }
 
-#ifndef DISABLE_SINGLE_EXECUTABLE_APPLICATION
-  if (sea::IsSingleExecutable()) {
-    // TODO(addaleax): Find a way to reuse:
-    //
-    // LoadEnvironment(Environment*, const char*)
-    //
-    // instead and not add yet another main entry point here because this
-    // already duplicates existing code.
-    return StartExecution(env, "internal/main/single_executable_application");
-  }
-#endif
-
   if (first_argv == "inspect") {
     return StartExecution(env, "internal/main/inspect");
   }

src/node.h

@@ -682,6 +682,7 @@ NODE_EXTERN std::unique_ptr<InspectorParentHandle> GetInspectorParentHandle(
 struct StartExecutionCallbackInfo {
   v8::Local<v8::Object> process_object;
   v8::Local<v8::Function> native_require;
+  v8::Local<v8::Function> run_cjs;
 };
 
 using StartExecutionCallback =
@@ -691,8 +692,7 @@ NODE_EXTERN v8::MaybeLocal<v8::Value> LoadEnvironment(
     Environment* env,
     StartExecutionCallback cb);
 NODE_EXTERN v8::MaybeLocal<v8::Value> LoadEnvironment(
-    Environment* env,
-    const char* main_script_source_utf8);
+    Environment* env, std::string_view main_script_source_utf8);
 NODE_EXTERN void FreeEnvironment(Environment* env);
 
 // Set a callback that is called when process.exit() is called from JS,

src/node_builtins.cc

@@ -185,17 +185,14 @@ static std::string OnDiskFileName(const char* id) {
 MaybeLocal<String> BuiltinLoader::LoadBuiltinSource(Isolate* isolate,
                                                     const char* id) const {
   auto source = source_.read();
-#ifdef NODE_BUILTIN_MODULES_PATH
-  if (strncmp(id, "embedder_main_", strlen("embedder_main_")) == 0) {
-#endif  // NODE_BUILTIN_MODULES_PATH
-    const auto source_it = source->find(id);
-    if (UNLIKELY(source_it == source->end())) {
-      fprintf(stderr, "Cannot find native builtin: \"%s\".\n", id);
-      ABORT();
-    }
-    return source_it->second.ToStringChecked(isolate);
-#ifdef NODE_BUILTIN_MODULES_PATH
+#ifndef NODE_BUILTIN_MODULES_PATH
+  const auto source_it = source->find(id);
+  if (UNLIKELY(source_it == source->end())) {
+    fprintf(stderr, "Cannot find native builtin: \"%s\".\n", id);
+    ABORT();
   }
+  return source_it->second.ToStringChecked(isolate);
+#else   // !NODE_BUILTIN_MODULES_PATH
   std::string filename = OnDiskFileName(id);
 
   std::string contents;
@@ -395,12 +392,6 @@ MaybeLocal<Function> BuiltinLoader::LookupAndCompile(Local<Context> context,
         FIXED_ONE_BYTE_STRING(isolate, "internalBinding"),
         FIXED_ONE_BYTE_STRING(isolate, "primordials"),
     };
-  } else if (strncmp(id, "embedder_main_", strlen("embedder_main_")) == 0) {
-    // Synthetic embedder main scripts from LoadEnvironment(): process, require
-    parameters = {
-        FIXED_ONE_BYTE_STRING(isolate, "process"),
-        FIXED_ONE_BYTE_STRING(isolate, "require"),
-    };
   } else {
     // others: exports, require, module, process, internalBinding, primordials
     parameters = {
@@ -457,12 +448,6 @@ MaybeLocal<Value> BuiltinLoader::CompileAndCall(Local<Context> context,
                  realm->builtin_module_require(),
                  realm->internal_binding_loader(),
                  realm->primordials()};
-  } else if (strncmp(id, "embedder_main_", strlen("embedder_main_")) == 0) {
-    // Synthetic embedder main scripts from LoadEnvironment(): process, require
-    arguments = {
-        realm->process_object(),
-        realm->builtin_module_require(),
-    };
   } else {
     // This should be invoked with the other CompileAndCall() methods, as
     // we are unable to generate the arguments.

src/node_main_instance.cc

@@ -9,6 +9,7 @@
 #include "node_internals.h"
 #include "node_options-inl.h"
 #include "node_realm.h"
+#include "node_sea.h"
 #include "node_snapshot_builder.h"
 #include "node_snapshotable.h"
 #include "node_v8_platform-inl.h"
@@ -86,7 +87,16 @@ ExitCode NodeMainInstance::Run() {
 
 void NodeMainInstance::Run(ExitCode* exit_code, Environment* env) {
   if (*exit_code == ExitCode::kNoFailure) {
-    LoadEnvironment(env, StartExecutionCallback{});
+    bool is_sea = false;
+#ifndef DISABLE_SINGLE_EXECUTABLE_APPLICATION
+    if (sea::IsSingleExecutable()) {
+      is_sea = true;
+      LoadEnvironment(env, sea::FindSingleExecutableCode());
+    }
+#endif
+    if (!is_sea) {
+      LoadEnvironment(env, StartExecutionCallback{});
+    }
 
     *exit_code =
         SpinEventLoopInternal(env).FromMaybe(ExitCode::kGenericUserError);