1 files changed, 56 insertions, 0 deletions
diff --git a/extensions/crypto/lib.rs b/extensions/crypto/lib.rs
new file mode 100644
index 000000000..45473f4d5
--- /dev/null
+++ b/extensions/crypto/lib.rs
@@ -0,0 +1,56 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+
+use deno_core::error::null_opbuf;
+use deno_core::error::AnyError;
+use deno_core::include_js_files;
+use deno_core::op_sync;
+use deno_core::Extension;
+use deno_core::OpState;
+use deno_core::ZeroCopyBuf;
+use rand::rngs::StdRng;
+use rand::thread_rng;
+use rand::Rng;
+use rand::SeedableRng;
+use std::path::PathBuf;
+
+pub use rand; // Re-export rand
+
+pub fn init(maybe_seed: Option<u64>) -> Extension {
+  Extension::builder()
+    .js(include_js_files!(
+      prefix "deno:extensions/crypto",
+      "01_crypto.js",
+    ))
+    .ops(vec![(
+      "op_crypto_get_random_values",
+      op_sync(op_crypto_get_random_values),
+    )])
+    .state(move |state| {
+      if let Some(seed) = maybe_seed {
+        state.put(StdRng::seed_from_u64(seed));
+      }
+      Ok(())
+    })
+    .build()
+}
+
+pub fn op_crypto_get_random_values(
+  state: &mut OpState,
+  _args: (),
+  zero_copy: Option<ZeroCopyBuf>,
+) -> Result<(), AnyError> {
+  let mut zero_copy = zero_copy.ok_or_else(null_opbuf)?;
+  let maybe_seeded_rng = state.try_borrow_mut::<StdRng>();
+  if let Some(seeded_rng) = maybe_seeded_rng {
+    seeded_rng.fill(&mut *zero_copy);
+  } else {
+    let mut rng = thread_rng();
+    rng.fill(&mut *zero_copy);
+  }
+
+  Ok(())
+}
+
+pub fn get_declaration() -> PathBuf {
+  PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("lib.deno_crypto.d.ts")
+}