Bug 898559 - Add metadata API for add-on globals. r=bholley

js/xpconnect/idl/xpccomponents.idl

@@ -120,7 +120,7 @@ interface ScheduledGCCallback : nsISupports
 /**
 * interface of Components.utils
 */
-[scriptable, uuid(35d5b0e5-9b29-48de-9f79-d2534b497435)]
+[scriptable, uuid(c9ccec7a-726c-4479-9438-6f51f6ef4170)]
 interface nsIXPCComponents_Utils : nsISupports
 {
 
@@ -172,6 +172,32 @@ interface nsIXPCComponents_Utils : nsISupports
                         [optional] in jsval filename,
                         [optional] in long lineNo);
 
+    /*
+     * getSandboxMetadata is designed to be called from JavaScript only.
+     *
+     * getSandboxMetadata retrieves the metadata associated with
+     * a sandbox object. It will return undefined if there
+     * is no metadata attached to the sandbox.
+     *
+     * var s = C.u.Sandbox(..., { metadata: "metadata" });
+     * var metadata = C.u.getSandboxMetadata(s);
+     */
+    [implicit_jscontext]
+    jsval getSandboxMetadata(in jsval sandbox);
+
+    /*
+     * setSandboxMetadata is designed to be called from JavaScript only.
+     *
+     * setSandboxMetadata sets the metadata associated with
+     * a sandbox object.
+     *
+     * Note that the metadata object will be copied before being used.
+     * The copy will be performed using the structured clone algorithm.
+     * Note that this algorithm does not support reflectors and
+     * it will throw if it encounters them.
+     */
+    [implicit_jscontext]
+    void setSandboxMetadata(in jsval sandbox, in jsval metadata);
 
     /*
      * import is designed to be called from JavaScript only.

js/xpconnect/src/Sandbox.cpp

@@ -585,9 +585,11 @@ sandbox_convert(JSContext *cx, HandleObject obj, JSType type, MutableHandleValue
     return JS_ConvertStub(cx, obj, type, vp);
 }
 
+#define XPCONNECT_SANDBOX_CLASS_METADATA_SLOT (XPCONNECT_GLOBAL_EXTRA_SLOT_OFFSET)
+
 static JSClass SandboxClass = {
     "Sandbox",
-    XPCONNECT_GLOBAL_FLAGS,
+    XPCONNECT_GLOBAL_FLAGS_WITH_EXTRA_SLOTS(1),
     JS_PropertyStub,   JS_DeletePropertyStub, JS_PropertyStub, JS_StrictPropertyStub,
     sandbox_enumerate, sandbox_resolve, sandbox_convert,  sandbox_finalize,
     NULL, NULL, NULL, NULL, TraceXPCGlobal
@@ -1041,6 +1043,8 @@ xpc::CreateSandboxObject(JSContext *cx, jsval *vp, nsISupports *prinOrSop, Sandb
     // about:memory may use that information
     xpc::SetLocationForGlobal(sandbox, options.sandboxName);
 
+    xpc::SetSandboxMetadata(cx, sandbox, options.metadata);
+
     JS_FireOnNewGlobalObject(cx, sandbox);
 
     return NS_OK;
@@ -1338,6 +1342,10 @@ ParseOptionsObject(JSContext *cx, jsval from, SandboxOptions &options)
     NS_ENSURE_SUCCESS(rv, rv);
 
     rv = GetDOMConstructorsFromOptions(cx, optionsObject, options);
+
+    bool found;
+    rv = GetPropFromOptions(cx, optionsObject,
+                            "metadata", &options.metadata, &found);
     NS_ENSURE_SUCCESS(rv, rv);
 
     return NS_OK;
@@ -1650,3 +1658,40 @@ xpc::NewFunctionForwarder(JSContext *cx, HandleId id, HandleObject callable, boo
     vp.setObject(*funobj);
     return true;
 }
+
+
+nsresult
+xpc::GetSandboxMetadata(JSContext *cx, HandleObject sandbox, MutableHandleValue rval)
+{
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(IsSandbox(sandbox));
+
+    RootedValue metadata(cx);
+    {
+      JSAutoCompartment ac(cx, sandbox);
+      metadata = JS_GetReservedSlot(sandbox, XPCONNECT_SANDBOX_CLASS_METADATA_SLOT);
+    }
+
+    if (!JS_WrapValue(cx, metadata.address()))
+        return NS_ERROR_UNEXPECTED;
+
+    rval.set(metadata);
+    return NS_OK;
+}
+
+nsresult
+xpc::SetSandboxMetadata(JSContext *cx, HandleObject sandbox, HandleValue metadataArg)
+{
+    MOZ_ASSERT(NS_IsMainThread());
+    MOZ_ASSERT(IsSandbox(sandbox));
+
+    RootedValue metadata(cx);
+
+    JSAutoCompartment ac(cx, sandbox);
+    if (!JS_StructuredClone(cx, metadataArg, metadata.address(), NULL, NULL))
+        return NS_ERROR_UNEXPECTED;
+
+    JS_SetReservedSlot(sandbox, XPCONNECT_SANDBOX_CLASS_METADATA_SLOT, metadata);
+
+    return NS_OK;
+}

js/xpconnect/src/XPCComponents.cpp

@@ -2830,6 +2830,46 @@ nsXPCComponents_Utils::EvalInSandbox(const nsAString& source,
     return NS_OK;
 }
 
+NS_IMETHODIMP
+nsXPCComponents_Utils::GetSandboxMetadata(const JS::Value &sandboxVal,
+                                          JSContext *cx, JS::Value *rval)
+{
+    if (!sandboxVal.isObject())
+        return NS_ERROR_INVALID_ARG;
+
+    RootedObject sandbox(cx, &sandboxVal.toObject());
+    sandbox = js::CheckedUnwrap(sandbox);
+    if (!sandbox || !xpc::IsSandbox(sandbox))
+        return NS_ERROR_INVALID_ARG;
+
+    RootedValue metadata(cx);
+    nsresult rv = xpc::GetSandboxMetadata(cx, sandbox, &metadata);
+    NS_ENSURE_SUCCESS(rv, rv);
+    *rval = metadata;
+
+    return NS_OK;
+}
+
+NS_IMETHODIMP
+nsXPCComponents_Utils::SetSandboxMetadata(const JS::Value &sandboxVal,
+                                          const JS::Value &metadataVal,
+                                          JSContext *cx)
+{
+    if (!sandboxVal.isObject())
+        return NS_ERROR_INVALID_ARG;
+
+    RootedObject sandbox(cx, &sandboxVal.toObject());
+    sandbox = js::CheckedUnwrap(sandbox);
+    if (!sandbox || !xpc::IsSandbox(sandbox))
+        return NS_ERROR_INVALID_ARG;
+
+    RootedValue metadata(cx, metadataVal);
+    nsresult rv = xpc::SetSandboxMetadata(cx, sandbox, metadata);
+    NS_ENSURE_SUCCESS(rv, rv);
+
+    return NS_OK;
+}
+
 /* JSObject import (in AUTF8String registryLocation,
  *                  [optional] in JSObject targetObj);
  */

js/xpconnect/src/xpcprivate.h

@@ -3604,6 +3604,7 @@ struct SandboxOptions {
         , wantExportHelpers(false)
         , proto(xpc_GetSafeJSContext())
         , sameZoneAs(xpc_GetSafeJSContext())
+        , metadata(xpc_GetSafeJSContext())
     { }
 
     bool wantXrays;
@@ -3613,6 +3614,7 @@ struct SandboxOptions {
     nsCString sandboxName;
     JS::RootedObject sameZoneAs;
     DOMConstructors DOMConstructors;
+    JS::RootedValue metadata;
 };
 
 JSObject *
@@ -3647,8 +3649,19 @@ EvalInSandbox(JSContext *cx, JS::HandleObject sandbox, const nsAString& source,
               JSVersion jsVersion, bool returnStringOnly,
               JS::MutableHandleValue rval);
 
+// Helper for retrieving metadata stored in a reserved slot. The metadata
+// is set during the sandbox creation using the "metadata" option.
+nsresult
+GetSandboxMetadata(JSContext *cx, JS::HandleObject sandboxArg,
+                   JS::MutableHandleValue rval);
+
+nsresult
+SetSandboxMetadata(JSContext *cx, JS::HandleObject sandboxArg,
+                   JS::HandleValue metadata);
+
 } /* namespace xpc */
 
+
 /***************************************************************************/
 // Inlined utilities.
 

js/xpconnect/tests/unit/test_sandbox_metadata.js

@@ -0,0 +1,45 @@
+/* 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/. */
+
+/* See https://bugzilla.mozilla.org/show_bug.cgi?id=898559 */
+
+function run_test()
+{
+  let sandbox = Components.utils.Sandbox("http://www.blah.com", {
+    metadata: "test metadata"
+  });
+
+  do_check_eq(Components.utils.getSandboxMetadata(sandbox), "test metadata");
+
+  let sandbox = Components.utils.Sandbox("http://www.blah.com", {
+    metadata: { foopy: { bar: 2 }, baz: "hi" }
+  });
+
+  let metadata = Components.utils.getSandboxMetadata(sandbox);
+  do_check_eq(metadata.baz, "hi");
+  do_check_eq(metadata.foopy.bar, 2);
+  metadata.baz = "foo";
+
+  metadata = Components.utils.getSandboxMetadata(sandbox);
+  do_check_eq(metadata.baz, "foo");
+
+  metadata = { foo: "bar" };
+  Components.utils.setSandboxMetadata(sandbox, metadata);
+  metadata.foo = "baz";
+  metadata = Components.utils.getSandboxMetadata(sandbox);
+  do_check_eq(metadata.foo, "bar");
+
+  let thrown = false;
+  let reflector = Components.classes["@mozilla.org/xmlextras/xmlhttprequest;1"]
+                    .createInstance(Components.interfaces.nsIXMLHttpRequest);
+
+  try {
+    Components.utils.setSandboxMetadata(sandbox, { foo: reflector });
+  } catch(e) {
+    thrown = true;
+  }
+
+  do_check_eq(thrown, true);
+}
+

js/xpconnect/tests/unit/xpcshell.ini

@@ -51,6 +51,7 @@ fail-if = os == "android"
 [test_allowedDomains.js]
 [test_allowedDomainsXHR.js]
 [test_nuke_sandbox.js]
+[test_sandbox_metadata.js]
 [test_exportFunction.js]
 [test_textDecoder.js]
 [test_watchdog_enable.js]