1 files changed, 33 insertions, 0 deletions
diff --git a/serde_v8/src/keys.rs b/serde_v8/src/keys.rs
new file mode 100644
index 000000000..ea989086c
--- /dev/null
+++ b/serde_v8/src/keys.rs
@@ -0,0 +1,33 @@
+// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
+use rusty_v8 as v8;
+
+use std::collections::HashMap;
+
+// KeyCache stores a pool struct keys mapped to v8,
+// to minimize allocs and speed up decoding/encoding `v8::Object`s
+// TODO: experiment with in from_v8/to_v8
+pub struct KeyCache(HashMap<&'static str, v8::Global<v8::String>>);
+
+// creates an optimized v8::String for a struct field
+// TODO: experiment with external strings
+// TODO: evaluate if own KeyCache is better than v8's dedupe
+pub fn v8_struct_key<'s>(
+  scope: &mut v8::HandleScope<'s>,
+  field: &'static str,
+) -> v8::Local<'s, v8::String> {
+  // Internalized v8 strings are significantly faster than "normal" v8 strings
+  // since v8 deduplicates re-used strings minimizing new allocations
+  // see: https://github.com/v8/v8/blob/14ac92e02cc3db38131a57e75e2392529f405f2f/include/v8.h#L3165-L3171
+  v8::String::new_from_utf8(
+    scope,
+    field.as_ref(),
+    v8::NewStringType::Internalized,
+  )
+  .unwrap()
+
+  // TODO: consider external strings later
+  // right now non-deduped external strings (without KeyCache)
+  // are slower than the deduped internalized strings by ~2.5x
+  // since they're a new string in v8's eyes and needs to be hashed, etc...
+  // v8::String::new_external_onebyte_static(scope, field).unwrap()
+}