gecko-dev/js/public/Exception.h
2020-04-09 12:35:59 +00:00

70 lines
2.5 KiB
C++

/* -*- 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/. */
#ifndef js_Exception_h
#define js_Exception_h
#include "mozilla/Attributes.h"
#include "jspubtd.h"
#include "js/RootingAPI.h" // JS::{Handle,Rooted}
#include "js/Value.h" // JS::Value, JS::Handle<JS::Value>
namespace JS {
// This class encapsulates a (pending) exception and the corresponding optional
// SavedFrame stack object captured when the pending exception was set
// on the JSContext. This fuzzily correlates with a `throw` statement in JS,
// although arbitrary JSAPI consumers or VM code may also set pending exceptions
// via `JS_SetPendingException`.
//
// This is not the same stack as `e.stack` when `e` is an `Error` object.
// (That would be JS::ExceptionStackOrNull).
class MOZ_STACK_CLASS ExceptionStack {
Rooted<Value> exception_;
Rooted<JSObject*> stack_;
friend JS_PUBLIC_API bool GetPendingExceptionStack(
JSContext* cx, JS::ExceptionStack* exceptionStack);
void init(HandleValue exception, HandleObject stack) {
exception_ = exception;
stack_ = stack;
}
public:
explicit ExceptionStack(JSContext* cx) : exception_(cx), stack_(cx) {}
ExceptionStack(JSContext* cx, HandleValue exception, HandleObject stack)
: exception_(cx, exception), stack_(cx, stack) {}
HandleValue exception() const { return exception_; }
// |stack| can be null.
HandleObject stack() const { return stack_; }
};
// Get the current pending exception value and stack.
// This function asserts that there is a pending exception.
// If this function returns false, then retrieving the current pending exception
// failed and might have been overwritten by a new exception.
extern JS_PUBLIC_API bool GetPendingExceptionStack(
JSContext* cx, JS::ExceptionStack* exceptionStack);
// Similar to GetPendingExceptionStack, but also clears the current
// pending exception.
extern JS_PUBLIC_API bool StealPendingExceptionStack(
JSContext* cx, JS::ExceptionStack* exceptionStack);
// Set both the exception value and its associated stack on the context as
// the current pending exception.
extern JS_PUBLIC_API void SetPendingExceptionStack(
JSContext* cx, const JS::ExceptionStack& exceptionStack);
} // namespace JS
#endif // js_Exception_h