gecko/dom/bindings/Nullable.h
Boris Zbarsky 32c7f6e634 Bug 742217. Reduce the use of nested namespaces in our binding code. r=peterv,bent
In the new setup, all per-interface DOM binding files are exported into
mozilla/dom.  General files not specific to an interface are also exported into
mozilla/dom.

In terms of namespaces, most things now live in mozilla::dom.  Each interface
Foo that has generated code has a mozilla::dom::FooBinding namespace for said
generated code (and possibly a mozilla::bindings::FooBinding_workers if there's
separate codegen for workers).

IDL enums are a bit weird: since the name of the enum and the names of its
entries all end up in the same namespace, we still generate a C++ namespace
with the name of the IDL enum type with "Values" appended to it, with a
::valuelist inside for the actual C++ enum.  We then typedef
EnumFooValues::valuelist to EnumFoo.  That makes it a bit more difficult to
refer to the values, but means that values from different enums don't collide
with each other.

The enums with the proto and constructor IDs in them now live under the
mozilla::dom::prototypes and mozilla::dom::constructors namespaces respectively.
Again, this lets us deal sanely with the whole "enum value names are flattened
into the namespace the enum is in" deal.

The main benefit of this setup (and the reason "Binding" got appended to the
per-interface namespaces) is that this way "using mozilla::dom" should Just
Work for consumers and still allow C++ code to sanely use the IDL interface
names for concrete classes, which is fairly desirable.

--HG--
rename : dom/bindings/Utils.cpp => dom/bindings/BindingUtils.cpp
rename : dom/bindings/Utils.h => dom/bindings/BindingUtils.h
2012-05-03 00:35:38 -04:00

64 lines
1.3 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-*/
/* vim: set ts=2 sw=2 et tw=79: */
/* 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 mozilla_dom_Nullable_h
#define mozilla_dom_Nullable_h
#include "mozilla/Assertions.h"
namespace mozilla {
namespace dom {
// Support for nullable types
template <typename T>
struct Nullable
{
private:
T mValue;
bool mIsNull;
public:
Nullable()
: mIsNull(true)
{}
Nullable(T aValue)
: mValue(aValue)
, mIsNull(false)
{}
void SetValue(T aValue) {
mValue = aValue;
mIsNull = false;
}
// For cases when |T| is some type with nontrivial copy behavior, we may want
// to get a reference to our internal copy of T and work with it directly
// instead of relying on the copying version of SetValue().
T& SetValue() {
mIsNull = false;
return mValue;
}
void SetNull() {
mIsNull = true;
}
const T& Value() const {
MOZ_ASSERT(!mIsNull);
return mValue;
}
bool IsNull() const {
return mIsNull;
}
};
} // namespace dom
} // namespace mozilla
#endif /* mozilla_dom_Nullable_h */