gecko-dev/xpcom/ds/nsIPropertyBag2.idl
Kris Maglione 35305e871d Bug 1581859: Part 3a - Add do_GetProperty helper for nsIPropertyBag2. r=mccr8
There currently isn't a typesafe way to get a property with a given interface
from a property bag from C++. This patch adds one, following the pattern of
similar helpers, like `do_GetInterface`.

Differential Revision: https://phabricator.services.mozilla.com/D103210
2021-03-25 19:47:01 +00:00

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/* 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/. */
/* nsIVariant based Property Bag support. */
#include "nsIPropertyBag.idl"
[scriptable, uuid(625cfd1e-da1e-4417-9ee9-dbc8e0b3fd79)]
interface nsIPropertyBag2 : nsIPropertyBag
{
// Accessing a property as a different type may attempt conversion to the
// requested value
int32_t getPropertyAsInt32 (in AString prop);
uint32_t getPropertyAsUint32 (in AString prop);
int64_t getPropertyAsInt64 (in AString prop);
uint64_t getPropertyAsUint64 (in AString prop);
double getPropertyAsDouble (in AString prop);
AString getPropertyAsAString (in AString prop);
ACString getPropertyAsACString (in AString prop);
AUTF8String getPropertyAsAUTF8String (in AString prop);
boolean getPropertyAsBool (in AString prop);
/**
* This method returns null if the value exists, but is null.
*
* Note: C++ callers should not use this method. They should use the
* typesafe `do_GetProperty` wrapper instead.
*/
void getPropertyAsInterface (in AString prop,
in nsIIDRef iid,
[iid_is(iid), retval] out nsQIResult result);
/**
* This method returns null if the value does not exist,
* or exists but is null.
*/
nsIVariant get (in AString prop);
/**
* Check for the existence of a key.
*/
boolean hasKey (in AString prop);
};
%{C++
#include "nsCOMPtr.h"
#include "nsAString.h"
class MOZ_STACK_CLASS nsGetProperty final : public nsCOMPtr_helper {
public:
nsGetProperty(nsIPropertyBag2* aPropBag, const nsAString& aPropName, nsresult* aError)
: mPropBag(aPropBag), mPropName(aPropName), mErrorPtr(aError) {}
virtual nsresult NS_FASTCALL operator()(const nsIID&, void**) const override;
private:
nsIPropertyBag2* MOZ_NON_OWNING_REF mPropBag;
const nsAString& mPropName;
nsresult* mErrorPtr;
};
/**
* A typesafe wrapper around nsIPropertyBag2::GetPropertyAsInterface. Similar
* to the `do_QueryInterface` family of functions, when assigned to a
* `nsCOMPtr` of a given type, attempts to query the given property to that
* type.
*
* If `aError` is passed, the return value of `GetPropertyAsInterface` is
* stored in it.
*/
inline const nsGetProperty do_GetProperty(nsIPropertyBag2* aPropBag,
const nsAString& aPropName,
nsresult* aError = 0) {
return nsGetProperty(aPropBag, aPropName, aError);
}
%}