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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** BEGIN LICENSE BLOCK *****
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
* http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
* Pierre Phaneuf <pp@ludusdesign.com>
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*
* ***** END LICENSE BLOCK ***** */
/**
*
* A sample of XPConnect. This file contains an implementation nsSample
* of the interface nsISample.
*
*/
#include <stdio.h>
#include "nsSample.h"
#include "nsMemory.h"
#include "nsEmbedString.h"
////////////////////////////////////////////////////////////////////////
nsSampleImpl::nsSampleImpl() : mValue(nsnull)
{
mValue = (char*)nsMemory::Clone("initial value", 14);
}
nsSampleImpl::~nsSampleImpl()
{
if (mValue)
nsMemory::Free(mValue);
}
/**
* NS_IMPL_ISUPPORTS1 expands to a simple implementation of the nsISupports
* interface. This includes a proper implementation of AddRef, Release,
* and QueryInterface. If this class supported more interfaces than just
* nsISupports,
* you could use NS_IMPL_ADDREF() and NS_IMPL_RELEASE() to take care of the
* simple stuff, but you would have to create QueryInterface on your own.
* nsSampleFactory.cpp is an example of this approach.
* Notice that the second parameter to the macro is name of the interface, and
* NOT the #defined IID.
*
* The _CI variant adds support for nsIClassInfo, which permits introspection
* and interface flattening.
*/
NS_IMPL_ISUPPORTS1_CI(nsSampleImpl, nsISample)
/**
* Notice that in the protoype for this function, the NS_IMETHOD macro was
* used to declare the return type. For the implementation, the return
* type is declared by NS_IMETHODIMP
*/
NS_IMETHODIMP
nsSampleImpl::GetValue(char** aValue)
{
NS_PRECONDITION(aValue != nsnull, "null ptr");
if (! aValue)
return NS_ERROR_NULL_POINTER;
if (mValue) {
/**
* GetValue's job is to return data known by an instance of
* nsSampleImpl to the outside world. If we were to simply return
* a pointer to data owned by this instance, and the client were to
* free it, bad things would surely follow.
* On the other hand, if we create a new copy of the data for our
* client, and it turns out that client is implemented in JavaScript,
* there would be no way to free the buffer. The solution to the
* buffer ownership problem is the nsMemory singleton. Any buffer
* returned by an XPCOM method should be allocated by the nsMemory.
* This convention lets things like JavaScript reflection do their
* job, and simplifies the way C++ clients deal with returned buffers.
*/
*aValue = (char*) nsMemory::Clone(mValue, strlen(mValue) + 1);
if (! *aValue)
return NS_ERROR_NULL_POINTER;
}
else {
*aValue = nsnull;
}
return NS_OK;
}
NS_IMETHODIMP
nsSampleImpl::SetValue(const char* aValue)
{
NS_PRECONDITION(aValue != nsnull, "null ptr");
if (! aValue)
return NS_ERROR_NULL_POINTER;
if (mValue) {
nsMemory::Free(mValue);
}
/**
* Another buffer passing convention is that buffers passed INTO your
* object ARE NOT YOURS. Keep your hands off them, unless they are
* declared "inout". If you want to keep the value for posterity,
* you will have to make a copy of it.
*/
mValue = (char*) nsMemory::Clone(aValue, strlen(aValue) + 1);
return NS_OK;
}
NS_IMETHODIMP
nsSampleImpl::Poke(const char* aValue)
{
return SetValue((char*) aValue);
}
static void GetStringValue(nsACString& aValue)
{
NS_CStringSetData(aValue, "GetValue");
}
NS_IMETHODIMP
nsSampleImpl::WriteValue(const char* aPrefix)
{
NS_PRECONDITION(aPrefix != nsnull, "null ptr");
if (! aPrefix)
return NS_ERROR_NULL_POINTER;
printf("%s %s\n", aPrefix, mValue);
// This next part illustrates the nsEmbedString:
nsEmbedString foopy;
foopy.Append(PRUnichar('f'));
foopy.Append(PRUnichar('o'));
foopy.Append(PRUnichar('o'));
foopy.Append(PRUnichar('p'));
foopy.Append(PRUnichar('y'));
const PRUnichar* f = foopy.get();
PRUint32 l = foopy.Length();
printf("%c%c%c%c%c %d\n", char(f[0]), char(f[1]), char(f[2]), char(f[3]), char(f[4]), l);
nsEmbedCString foopy2;
GetStringValue(foopy2);
//foopy2.AppendLiteral("foopy");
const char* f2 = foopy2.get();
PRUint32 l2 = foopy2.Length();
printf("%s %d\n", f2, l2);
return NS_OK;
}
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