Rewrite snapshot_creator in Rust

1 files changed, 44 insertions, 0 deletions

diff --git a/core/snapshot_creator.rs b/core/snapshot_creator.rs
new file mode 100644
index 000000000..1d43b9174
--- /dev/null
+++ b/core/snapshot_creator.rs
@@ -0,0 +1,44 @@
+// Note: This is a nearly identical rewrite of core/libdeno/snapshot_creator.cc
+// but in Rust.
+//
+// This snapshot program is considered "basic" because the code being
+// snapshotted cannot call ops.
+
+extern crate deno;
+
+use deno::js_check;
+use deno::Isolate;
+use deno::StartupData;
+use std::env;
+use std::io::Write;
+
+fn main() {
+  let args: Vec<String> = env::args().collect();
+  // NOTE: `--help` arg will display V8 help and exit
+  let args = deno::v8_set_flags(args);
+
+  let (snapshot_out_bin, js_filename) = if args.len() == 3 {
+    (args[1].clone(), args[2].clone())
+  } else {
+    eprintln!("Usage: snapshot_creator <out_filename> <js_filename>");
+    std::process::exit(1);
+  };
+
+  let js_source =
+    std::fs::read(&js_filename).expect("couldn't read js_filename");
+  let js_source_str = std::str::from_utf8(&js_source).unwrap();
+
+  let will_snapshot = true;
+  let mut isolate = Isolate::new(StartupData::None, will_snapshot);
+
+  js_check(isolate.execute(&js_filename, js_source_str));
+
+  let snapshot = isolate.snapshot().expect("error snapshotting");
+
+  let mut out_file = std::fs::File::create(snapshot_out_bin).unwrap();
+  let snapshot_slice =
+    unsafe { std::slice::from_raw_parts(snapshot.data_ptr, snapshot.data_len) };
+  out_file
+    .write_all(snapshot_slice)
+    .expect("Failed to write snapshot file");
+}