1 files changed, 44 insertions, 0 deletions
diff --git a/core/build_util.rs b/core/build_util.rs
new file mode 100644
index 000000000..04a0f870b
--- /dev/null
+++ b/core/build_util.rs
@@ -0,0 +1,44 @@
+//! Helper module used in cli/build.rs and runtime/build.rs
+use crate::JsRuntime;
+use std::path::Path;
+use std::path::PathBuf;
+
+pub fn create_snapshot(
+  mut js_runtime: JsRuntime,
+  snapshot_path: &Path,
+  files: Vec<PathBuf>,
+) {
+  // TODO(nayeemrmn): https://github.com/rust-lang/cargo/issues/3946 to get the
+  // workspace root.
+  let display_root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
+  for file in files {
+    println!("cargo:rerun-if-changed={}", file.display());
+    let display_path = file.strip_prefix(display_root).unwrap();
+    let display_path_str = display_path.display().to_string();
+    js_runtime
+      .execute(
+        &("deno:".to_string() + &display_path_str.replace('\\', "/")),
+        &std::fs::read_to_string(&file).unwrap(),
+      )
+      .unwrap();
+  }
+
+  let snapshot = js_runtime.snapshot();
+  let snapshot_slice: &[u8] = &*snapshot;
+  println!("Snapshot size: {}", snapshot_slice.len());
+  std::fs::write(&snapshot_path, snapshot_slice).unwrap();
+  println!("Snapshot written to: {} ", snapshot_path.display());
+}
+
+pub fn get_js_files(d: &Path) -> Vec<PathBuf> {
+  let mut js_files = std::fs::read_dir(d)
+    .unwrap()
+    .map(|dir_entry| {
+      let file = dir_entry.unwrap();
+      d.join(file.path())
+    })
+    .filter(|path| path.extension().unwrap_or_default() == "js")
+    .collect::<Vec<PathBuf>>();
+  js_files.sort();
+  js_files
+}