gecko-dev/xpcom/io/nsIObjectOutputStream.idl

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/. */

#include "nsIBinaryOutputStream.idl"
#include "nsrootidl.idl"

/**
 * @See nsIObjectInputStream
 * @See nsIBinaryOutputStream
 */

[scriptable, uuid(92c898ac-5fde-4b99-87b3-5d486422094b)]
interface nsIObjectOutputStream : nsIBinaryOutputStream
{
    /**
     * Write the object whose "root" or XPCOM-identity nsISupports is aObject.
     * The cause for writing this object is a strong or weak reference, so the
     * aIsStrongRef argument must tell which kind of pointer is being followed
     * here during serialization.
     *
     * If the object has only one strong reference in the serialization and no
     * weak refs, use writeSingleRefObject.  This is a valuable optimization:
     * it saves space in the stream, and cycles on both ends of the process.
     *
     * If the reference being serialized is a pointer to an interface not on
     * the primary inheritance chain ending in the root nsISupports, you must
     * call writeCompoundObject instead of this method.
     */
    void writeObject(in nsISupports aObject, in boolean aIsStrongRef);

    /**
     * Write an object referenced singly and strongly via its root nsISupports
     * or a subclass of its root nsISupports.  There must not be other refs to
     * aObject in memory, or in the serialization.
     */
    void writeSingleRefObject(in nsISupports aObject);

    /**
     * Write the object referenced by an interface pointer at aObject that
     * inherits from a non-primary nsISupports, i.e., a reference to one of
     * the multiply inherited interfaces derived from an nsISupports other
     * than the root or XPCOM-identity nsISupports; or a reference to an
     * inner object in the case of true XPCOM aggregation.  aIID identifies
     * this interface.
     */
    void writeCompoundObject(in nsISupports aObject,
                             in nsIIDRef aIID,
                             in boolean aIsStrongRef);

    void writeID(in nsIDRef aID);

    /**
     * Optimized serialization support -- see nsIStreamBufferAccess.idl.
     */
    [notxpcom] charPtr getBuffer(in uint32_t aLength, in uint32_t aAlignMask);
    [notxpcom] void    putBuffer(in charPtr aBuffer, in uint32_t aLength);
};

%{C++

inline nsresult
NS_WriteOptionalObject(nsIObjectOutputStream* aStream, nsISupports* aObject,
                       bool aIsStrongRef)
{
    bool nonnull = (aObject != nullptr);
    nsresult rv = aStream->WriteBoolean(nonnull);
    if (NS_SUCCEEDED(rv) && nonnull)
        rv = aStream->WriteObject(aObject, aIsStrongRef);
    return rv;
}

inline nsresult
NS_WriteOptionalSingleRefObject(nsIObjectOutputStream* aStream,
                                nsISupports* aObject)
{
    bool nonnull = (aObject != nullptr);
    nsresult rv = aStream->WriteBoolean(nonnull);
    if (NS_SUCCEEDED(rv) && nonnull)
        rv = aStream->WriteSingleRefObject(aObject);
    return rv;
}

inline nsresult
NS_WriteOptionalCompoundObject(nsIObjectOutputStream* aStream,
                               nsISupports* aObject,
                               const nsIID& aIID,
                               bool aIsStrongRef)
{
    bool nonnull = (aObject != nullptr);
    nsresult rv = aStream->WriteBoolean(nonnull);
    if (NS_SUCCEEDED(rv) && nonnull)
        rv = aStream->WriteCompoundObject(aObject, aIID, aIsStrongRef);
    return rv;
}

%}