Extended Symbol support (justjake#105)

* Symbol utilities

* rebuild

* update CHANGLOG.md

* rebuild docs

Author: justjake

CHANGELOG.md

@@ -2,10 +2,9 @@
 
 ## v0.22.0 (unreleased)
 
+- [#78](https://github.com/justjake/quickjs-emscripten/pull/78), [#105](https://github.com/justjake/quickjs-emscripten/pull/105) (thanks to @ayaboy) add Symbol helpers `context.newUniqueSymbol`, `context.newSymbolFor`, as well as support for symbols in `context.dump`.
 - [#104](https://github.com/justjake/quickjs-emscripten/pull/104) BigInt support.
-
 - [#100](https://github.com/justjake/quickjs-emscripten/pull/100) **Breaking change** upgrade Emscripten version and switch to `async import(...)` for loading variants.
-
   We also drop support for older browsers and Node versions:
 
   - Node >= 16 is required

c/interface.c

@@ -319,6 +319,69 @@ JSBorrowedChar *QTS_GetString(JSContext *ctx, JSValueConst *value) {
   return JS_ToCString(ctx, *value);
 }
 
+JSValue qts_get_symbol_key(JSContext *ctx, JSValueConst *value) {
+  JSValue global = JS_GetGlobalObject(ctx);
+  JSValue Symbol = JS_GetPropertyStr(ctx, global, "Symbol");
+  JS_FreeValue(ctx, global);
+
+  JSValue Symbol_keyFor = JS_GetPropertyStr(ctx, Symbol, "keyFor");
+  JSValue key = JS_Call(ctx, Symbol_keyFor, Symbol, 1, value);
+  JS_FreeValue(ctx, Symbol_keyFor);
+  JS_FreeValue(ctx, Symbol);
+  return key;
+}
+
+JSValue *QTS_NewSymbol(JSContext *ctx, BorrowedHeapChar *description, int isGlobal) {
+  JSValue global = JS_GetGlobalObject(ctx);
+  JSValue Symbol = JS_GetPropertyStr(ctx, global, "Symbol");
+  JS_FreeValue(ctx, global);
+  JSValue descriptionValue = JS_NewString(ctx, description);
+  JSValue symbol;
+
+  if (isGlobal != 0) {
+    JSValue Symbol_for = JS_GetPropertyStr(ctx, Symbol, "for");
+    symbol = JS_Call(ctx, Symbol_for, Symbol, 1, &descriptionValue);
+    JS_FreeValue(ctx, descriptionValue);
+    JS_FreeValue(ctx, Symbol_for);
+    JS_FreeValue(ctx, Symbol);
+    return jsvalue_to_heap(symbol);
+  }
+
+  symbol = JS_Call(ctx, Symbol, JS_UNDEFINED, 1, &descriptionValue);
+  JS_FreeValue(ctx, descriptionValue);
+  JS_FreeValue(ctx, Symbol);
+
+  return jsvalue_to_heap(symbol);
+}
+
+MaybeAsync(JSBorrowedChar *) QTS_GetSymbolDescriptionOrKey(JSContext *ctx, JSValueConst *value) {
+  JSBorrowedChar *result;
+
+  JSValue key = qts_get_symbol_key(ctx, value);
+  if (!JS_IsUndefined(key)) {
+    result = JS_ToCString(ctx, key);
+    JS_FreeValue(ctx, key);
+    return result;
+  }
+
+  JSValue description = JS_GetPropertyStr(ctx, *value, "description");
+  result = JS_ToCString(ctx, description);
+  JS_FreeValue(ctx, description);
+  return result;
+}
+
+int QTS_IsGlobalSymbol(JSContext *ctx, JSValueConst *value) {
+  JSValue key = qts_get_symbol_key(ctx, value);
+  int undefined = JS_IsUndefined(key);
+  JS_FreeValue(ctx, key);
+
+  if (undefined) {
+    return 0;
+  } else {
+    return 1;
+  }
+}
+
 int QTS_IsJobPending(JSRuntime *rt) {
   return JS_IsJobPending(rt);
 }

doc/README.md

@@ -569,8 +569,11 @@ the Javascript parts of the library without setting up the Emscripten toolchain.
 
 Intermediate object files from QuickJS end up in ./build/quickjs/.
 
-This project uses `emscripten 3.1.7` via Docker. You will need a working `docker`
-install to build the Emscripten artifacts.
+This project uses `emscripten 3.1.32`.
+
+- On ARM64, you should install `emscripten` on your machine. For example on macOS, `brew install emscripten`.
+- If _the correct version of emcc_ is not in your PATH, compilation falls back to using Docker.
+  On ARM64, this is 10-50x slower than native compilation, but it's just fine on x64.
 
 Related NPM scripts:
 
@@ -585,8 +588,7 @@ Related NPM scripts:
 The ./ts directory contains Typescript types and wraps the generated Emscripten
 FFI in a more usable interface.
 
-You'll need `node` and `npm` or `yarn`. Install dependencies with `npm install`
-or `yarn install`.
+You'll need `node` and `yarn`. Install dependencies with `yarn install`.
 
 - `yarn build` produces ./dist.
 - `yarn test` runs the tests.