Expose GC to guest code (#1410)

zipline/build.gradle.kts

@@ -137,6 +137,7 @@ kotlin {
           header(file("native/quickjs/quickjs.h"))
           header(file("native/common/context-no-eval.h"))
           header(file("native/common/finalization-registry.h"))
+          header(file("native/common/global-gc.h"))
           packageName("app.cash.zipline.quickjs")
         }
       }

zipline/native/Context.cpp

@@ -22,6 +22,7 @@
 #include "ExceptionThrowers.h"
 #include "common/context-no-eval.h"
 #include "common/finalization-registry.h"
+#include "common/global-gc.h"
 #include "quickjs/quickjs.h"
 
 /**
@@ -95,6 +96,8 @@ Context::Context(JNIEnv* env)
   JS_SetRuntimeOpaque(jsRuntime, this);
   JS_SetInterruptHandler(jsRuntime, &jsInterruptHandlerPoll, this);
 
+  JS_AddGlobalThisGc(jsContext);
+
   if (installFinalizationRegistry(jsContext, jsContextForCompiling) < 0) {
     throwJavaException(env, "java/lang/IllegalStateException",
                        "Failed to install FinalizationRegistry");

zipline/native/common/global-gc.c

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2024 Block, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "../quickjs/quickjs.h"
+#include "global-gc.h"
+
+static JSValue js_global_gc(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv) {
+  JS_RunGC(JS_GetRuntime(ctx));
+  return JS_UNDEFINED;
+}
+
+void JS_AddGlobalThisGc(JSContext *jsContext) {
+  JSValue gc = JS_NewCFunction(jsContext, js_global_gc, "gc", 0);
+  JSValue globalThis = JS_GetGlobalObject(jsContext);
+  JS_SetPropertyStr(jsContext, globalThis, "gc", gc);
+  JS_FreeValue(jsContext, globalThis);
+}

zipline/native/common/global-gc.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (C) 2024 Block, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#ifndef QUICKJS_ANDROID_GLOBALGC_H
+#define QUICKJS_ANDROID_GLOBALGC_H
+
+#include "../quickjs/quickjs.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void JS_AddGlobalThisGc(JSContext *jsContext);
+
+#ifdef __cplusplus
+} /* extern "C" { */
+#endif
+
+#endif //QUICKJS_ANDROID_GLOBALGC_H

zipline/src/hostTest/kotlin/app/cash/zipline/QuickJsTest.kt

@@ -65,4 +65,8 @@ class QuickJsTest {
       quickJs.evaluate("""["test", true, false, 1, 1.123, undefined, null];""") as Array<Any?>,
     )
   }
+
+  @Test fun gc() {
+    assertNull(quickJs.evaluate("""globalThis.gc();"""))
+  }
 }

zipline/src/nativeMain/kotlin/app/cash/zipline/QuickJs.kt

@@ -26,6 +26,7 @@ import app.cash.zipline.quickjs.JSContext
 import app.cash.zipline.quickjs.JSMemoryUsage
 import app.cash.zipline.quickjs.JSRuntime
 import app.cash.zipline.quickjs.JSValue
+import app.cash.zipline.quickjs.JS_AddGlobalThisGc
 import app.cash.zipline.quickjs.JS_ComputeMemoryUsage
 import app.cash.zipline.quickjs.JS_EVAL_FLAG_COMPILE_ONLY
 import app.cash.zipline.quickjs.JS_EVAL_FLAG_STRICT
@@ -152,6 +153,8 @@ actual class QuickJs private constructor(
   init {
     JS_SetRuntimeOpaque(runtime, thisPtr.asCPointer())
     JS_SetInterruptHandler(runtime, jsInterruptHandlerCFunction, thisPtr.asCPointer())
+
+    JS_AddGlobalThisGc(context)
   }
 
   private var closed = false