build: add "include_js_files_for_snapshotting" Cargo feature (#17826)

This allows to not include source code into the binary (because
it will already be included in the V8 snapshot).

Nothing changes for the embedders - everything should still build the
same.

This commit brings the binary size from 87Mb to 82Mb on M1.

Alternative to https://github.com/denoland/deno/pull/17820 and
https://github.com/denoland/deno/pull/17653

---------

Co-authored-by: Leo Kettmeir <crowlkats@toaxl.com>

1 files changed, 19 insertions, 14 deletions

diff --git a/runtime/build.rs b/runtime/build.rs
index a813d63cb..4678eab99 100644
--- a/runtime/build.rs
+++ b/runtime/build.rs
@@ -1,24 +1,25 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 
-use deno_core::include_js_files;
 use std::env;
 use std::path::PathBuf;
 
-// This is a shim that allows to generate documentation on docs.rs
-mod not_docs {
+#[cfg(all(
+  not(feature = "docsrs"),
+  not(feature = "dont_create_runtime_snapshot")
+))]
+mod startup_snapshot {
   use std::path::Path;
 
   use super::*;
-  use deno_cache::SqliteBackedCache;
-  use deno_core::snapshot_util::*;
-  use deno_core::Extension;
-
   use deno_ast::MediaType;
   use deno_ast::ParseParams;
   use deno_ast::SourceTextInfo;
+  use deno_cache::SqliteBackedCache;
   use deno_core::error::AnyError;
+  use deno_core::include_js_files;
+  use deno_core::snapshot_util::*;
+  use deno_core::Extension;
   use deno_core::ExtensionFileSource;
-  use deno_core::ExtensionFileSourceCode;
 
   fn transpile_ts_for_snapshotting(
     file_source: &ExtensionFileSource,
@@ -34,16 +35,15 @@ mod not_docs {
         file_source.specifier
       ),
     };
-
-    let ExtensionFileSourceCode::IncludedInBinary(code) = file_source.code;
+    let code = file_source.code.load()?;
 
     if !should_transpile {
-      return Ok(code.to_string());
+      return Ok(code);
     }
 
     let parsed = deno_ast::parse_module(ParseParams {
       specifier: file_source.specifier.to_string(),
-      text_info: SourceTextInfo::from_string(code.to_string()),
+      text_info: SourceTextInfo::from_string(code),
       media_type,
       capture_tokens: false,
       scope_analysis: false,
@@ -281,6 +281,7 @@ mod not_docs {
 
     #[cfg(not(feature = "snapshot_from_snapshot"))]
     {
+      use deno_core::ExtensionFileSourceCode;
       maybe_additional_extension = Some(
         Extension::builder("runtime_main")
           .dependencies(vec!["runtime"])
@@ -314,9 +315,13 @@ fn main() {
   // doesn't actually compile on docs.rs
   if env::var_os("DOCS_RS").is_some() {
     let snapshot_slice = &[];
+    #[allow(clippy::needless_borrow)]
     std::fs::write(&runtime_snapshot_path, snapshot_slice).unwrap();
   }
 
-  #[cfg(not(feature = "docsrs"))]
-  not_docs::build_snapshot(runtime_snapshot_path)
+  #[cfg(all(
+    not(feature = "docsrs"),
+    not(feature = "dont_create_runtime_snapshot")
+  ))]
+  startup_snapshot::build_snapshot(runtime_snapshot_path)
 }