summaryrefslogtreecommitdiffstats
path: root/dom/bindings/BindingCallContext.h
diff options
context:
space:
mode:
Diffstat (limited to '')
-rw-r--r--dom/bindings/BindingCallContext.h66
1 files changed, 66 insertions, 0 deletions
diff --git a/dom/bindings/BindingCallContext.h b/dom/bindings/BindingCallContext.h
new file mode 100644
index 0000000000..41978eb167
--- /dev/null
+++ b/dom/bindings/BindingCallContext.h
@@ -0,0 +1,66 @@
+/* -*- 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/. */
+
+/**
+ * A struct that encapsulates a JSContex and information about
+ * which binding method was called. The idea is to automatically annotate
+ * exceptions thrown via the BindingCallContext with the method name.
+ */
+
+#ifndef mozilla_dom_BindingCallContext_h
+#define mozilla_dom_BindingCallContext_h
+
+#include <utility>
+
+#include "js/TypeDecls.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/ErrorResult.h"
+
+namespace mozilla::dom {
+
+class MOZ_NON_TEMPORARY_CLASS MOZ_STACK_CLASS BindingCallContext {
+ public:
+ // aCx is allowed to be null. If it is, the BindingCallContext should
+ // generally act like a null JSContext*: test false when tested as a boolean
+ // and produce nullptr when used as a JSContext*.
+ //
+ // aMethodDescription should be something with longer lifetime than this
+ // BindingCallContext. Most simply, a string literal. nullptr or "" is
+ // allowed if we want to not have any particular message description. This
+ // argument corresponds to the "context" string used for DOM error codes that
+ // support one. See Errors.msg and the documentation for
+ // ErrorResult::MaybeSetPendingException for details on he context arg.
+ BindingCallContext(JSContext* aCx, const char* aMethodDescription)
+ : mCx(aCx), mDescription(aMethodDescription) {}
+
+ ~BindingCallContext() = default;
+
+ // Allow passing a BindingCallContext as a JSContext*, as needed.
+ operator JSContext*() const { return mCx; }
+
+ // Allow testing a BindingCallContext for falsiness, just like a
+ // JSContext* could be tested.
+ explicit operator bool() const { return !!mCx; }
+
+ // Allow throwing an error message, if it has a context.
+ template <dom::ErrNum errorNumber, typename... Ts>
+ bool ThrowErrorMessage(Ts&&... aMessageArgs) const {
+ static_assert(ErrorFormatHasContext[errorNumber],
+ "We plan to add a context; it better be expected!");
+ MOZ_ASSERT(mCx);
+ return dom::ThrowErrorMessage<errorNumber>(
+ mCx, mDescription, std::forward<Ts>(aMessageArgs)...);
+ }
+
+ private:
+ JSContext* const mCx;
+ const char* const mDescription;
+};
+
+} // namespace mozilla::dom
+
+#endif // mozilla_dom_BindingCallContext_h