process: split execution into main scripts

This patch splits the execution mode selection from the environment
setup in `lib/internal/bootstrap/node.js`, and split the entry point
of different execution mode into main scripts under
`lib/internal/main`:

- `check_syntax.js`: used when `-c`/`--check` which only checks the
  syntax of the input instead of executing it.
- `eval_stdin.js`: used when `-e` is passed without value and stdin
  is not a TTY (e.g. something is piped).
- `eval_string`: used when `-e` is passed along with a string argument
- `inspect.js`: for `node inspect`/`node debug`
- `print_bash_completion.js`: for `--completion-bash`
- `print_help.js`: for `--help`
- `prof_process.js`: for `--prof-process`
- `repl.js`: for the REPL
- `run_main_module.js`: used when a main module is passed
- `run_third_party_main.js`: for the legacy `_third_party_main.js`
  support
- `worker_thread.js`: for workers

This makes the entry points easier to navigate and paves the way
for customized v8 snapshots (that do not need to deserialize
execution mode setup) and better embedder APIs.

As an example, after this patch, for the most common case where
Node.js executes a user module as an entry point, it essentially
goes through:

- `lib/internal/per_context.js` to setup the v8 Context (which is
  also run when setting up contexts for the `vm` module)
- `lib/internal/bootstrap/loaders.js` to set up internal binding
  and builtin module loaders (that are separate from the loaders
  accessible in the user land).
- `lib/internal/bootstrap/node.js`: to set up the rest of the
  environment, including various globals and the process object
- `lib/internal/main/run_main_module.js`: which is selected from
  C++ to prepare execution of the user module.

This patch also removes `NativeModuleLoader::CompileAndCall` and
exposes `NativeModuleLoader::LookupAndCompile` directly so that
we can handle syntax errors and runtime errors of bootstrap
scripts differently.

PR-URL: https://github.com/nodejs/node/pull/25667
Reviewed-By: Anna Henningsen <anna@addaleax.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/src/node_internals.h b/src/node_internals.h
index 0d4fe74ebf..bf66c77e6f 100644
--- a/src/node_internals.h
+++ b/src/node_internals.h
@@ -268,8 +268,9 @@ bool SafeGetenv(const char* key, std::string* text);
 
 void DefineZlibConstants(v8::Local<v8::Object> target);
 
-void RunBootstrapping(Environment* env);
-void StartExecution(Environment* env, const char* main_script_id);
+v8::MaybeLocal<v8::Value> RunBootstrapping(Environment* env);
+v8::MaybeLocal<v8::Value> StartExecution(Environment* env,
+                                         const char* main_script_id);
 
 }  // namespace node