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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/*
+ * Functionality provided for the JSM component loader in Gecko, that requires
+ * its own unique manner of global environment and currently requires assistance
+ * from SpiderMonkey to do so.
+ *
+ * Embedders who aren't Gecko can ignore this header.
+ */
+
+#ifndef js_friend_JSMEnvironment_h
+#define js_friend_JSMEnvironment_h
+
+#include "jstypes.h" // JS_PUBLIC_API
+
+#include "js/GCVector.h" // JS::StackGCVector
+#include "js/TypeDecls.h"
+
+// A 'JSMEnvironment' refers to an environment chain constructed for JSM loading
+// in a shared global. Internally it is a NonSyntacticVariablesObject with a
+// corresponding extensible LexicalEnvironmentObject that is accessible by
+// JS_ExtensibleLexicalEnvironment. The |this| value of that lexical environment
+// is the NSVO itself.
+//
+// Normal global environment (ES6): JSM "global" environment:
+//
+// * - extensible lexical environment
+// | (code runs in this environment;
+// | `let/const` bindings go here)
+// |
+// * - JSMEnvironment (=== `this`)
+// | (`var` bindings go here)
+// |
+// * - extensible lexical environment * - extensible lexical environment
+// | (code runs in this environment; | (empty)
+// | `let/const` bindings go here) |
+// | |
+// * - actual global (=== `this`) * - shared JSM global
+// (var bindings go here; and (Object, Math, etc. live here)
+// Object, Math, etc. live here)
+
+namespace JS {
+
+/**
+ * Allocate a new environment in the current compartment that is compatible with
+ * JSM shared loading.
+ */
+extern JS_PUBLIC_API JSObject* NewJSMEnvironment(JSContext* cx);
+
+/**
+ * Execute the given script (copied into the current compartment if necessary)
+ * in the given JSMEnvironment. The script must have been compiled for
+ * hasNonSyntacticScope. The |jsmEnv| must have been previously allocated by
+ * |NewJSMEnvironment|.
+ *
+ * NOTE: The associated extensible lexical environment is reused.
+ */
+extern JS_PUBLIC_API bool ExecuteInJSMEnvironment(JSContext* cx,
+ Handle<JSScript*> script,
+ Handle<JSObject*> jsmEnv);
+
+// Additionally, target objects may be specified as required by the Gecko
+// subscript loader. These are wrapped in non-syntactic WithEnvironments and
+// temporarily placed on the environment chain.
+extern JS_PUBLIC_API bool ExecuteInJSMEnvironment(
+ JSContext* cx, Handle<JSScript*> script, Handle<JSObject*> jsmEnv,
+ Handle<StackGCVector<JSObject*>> targetObj);
+
+// Used by native methods to determine the JSMEnvironment of caller if possible
+// by looking at stack frames. Returns nullptr if top frame isn't a scripted
+// caller in a JSM.
+//
+// NOTE: This may find NonSyntacticVariablesObject generated by other embedding
+// such as a Gecko FrameScript. Caller can check the compartment if needed.
+extern JS_PUBLIC_API JSObject* GetJSMEnvironmentOfScriptedCaller(JSContext* cx);
+
+/**
+ * Determine if obj is a JSMEnvironment
+ *
+ * NOTE: This may return true for an NonSyntacticVariablesObject generated by
+ * other embedding such as a Gecko FrameScript. Caller can check compartment.
+ */
+extern JS_PUBLIC_API bool IsJSMEnvironment(JSObject* obj);
+
+} // namespace JS
+
+#endif // js_friend_JSMEnvironment_h