gecko-dev/xpcom/ds/nsEnumeratorUtils.cpp

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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 * for the specific language governing rights and limitations under the
 * License.
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 * The Original Code is mozilla.org code.
 *
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 * the Initial Developer. All Rights Reserved.
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 * Contributor(s):
 *
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#include "nsEnumeratorUtils.h"


nsArrayEnumerator::nsArrayEnumerator(nsISupportsArray* aValueArray)
    : mValueArray(aValueArray),
      mIndex(0)
{
    NS_IF_ADDREF(mValueArray);
}

nsArrayEnumerator::~nsArrayEnumerator(void)
{
    NS_IF_RELEASE(mValueArray);
}

NS_IMPL_ISUPPORTS1(nsArrayEnumerator, nsISimpleEnumerator)

NS_IMETHODIMP
nsArrayEnumerator::HasMoreElements(PRBool* aResult)
{
    NS_PRECONDITION(aResult != 0, "null ptr");
    if (! aResult)
        return NS_ERROR_NULL_POINTER;

    if (!mValueArray) {
        *aResult = PR_FALSE;
        return NS_OK;
    }

    PRUint32 cnt;
    nsresult rv = mValueArray->Count(&cnt);
    if (NS_FAILED(rv)) return rv;
    *aResult = (mIndex < (PRInt32) cnt);
    return NS_OK;
}

NS_IMETHODIMP
nsArrayEnumerator::GetNext(nsISupports** aResult)
{
    NS_PRECONDITION(aResult != 0, "null ptr");
    if (! aResult)
        return NS_ERROR_NULL_POINTER;

    if (!mValueArray) {
        *aResult = nsnull;
        return NS_OK;
    }

    PRUint32 cnt;
    nsresult rv = mValueArray->Count(&cnt);
    if (NS_FAILED(rv)) return rv;
    if (mIndex >= (PRInt32) cnt)
        return NS_ERROR_UNEXPECTED;

    *aResult = mValueArray->ElementAt(mIndex++);
    return NS_OK;
}

extern NS_COM nsresult
NS_NewArrayEnumerator(nsISimpleEnumerator* *result,
                      nsISupportsArray* array)
{
    nsArrayEnumerator* enumer = new nsArrayEnumerator(array);
    if (enumer == nsnull)
        return NS_ERROR_OUT_OF_MEMORY;
    *result = enumer; 
    NS_ADDREF(*result);
    return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////

nsSingletonEnumerator::nsSingletonEnumerator(nsISupports* aValue)
    : mValue(aValue)
{
    NS_IF_ADDREF(mValue);
    mConsumed = (mValue ? PR_FALSE : PR_TRUE);
}

nsSingletonEnumerator::~nsSingletonEnumerator()
{
    NS_IF_RELEASE(mValue);
}

NS_IMPL_ISUPPORTS1(nsSingletonEnumerator, nsISimpleEnumerator)

NS_IMETHODIMP
nsSingletonEnumerator::HasMoreElements(PRBool* aResult)
{
    NS_PRECONDITION(aResult != 0, "null ptr");
    if (! aResult)
        return NS_ERROR_NULL_POINTER;

    *aResult = !mConsumed;
    return NS_OK;
}


NS_IMETHODIMP
nsSingletonEnumerator::GetNext(nsISupports** aResult)
{
    NS_PRECONDITION(aResult != 0, "null ptr");
    if (! aResult)
        return NS_ERROR_NULL_POINTER;

    if (mConsumed)
        return NS_ERROR_UNEXPECTED;

    mConsumed = PR_TRUE;

    *aResult = mValue;
    NS_ADDREF(*aResult);
    return NS_OK;
}

extern "C" NS_COM nsresult
NS_NewSingletonEnumerator(nsISimpleEnumerator* *result,
                          nsISupports* singleton)
{
    nsSingletonEnumerator* enumer = new nsSingletonEnumerator(singleton);
    if (enumer == nsnull)
        return NS_ERROR_OUT_OF_MEMORY;
    *result = enumer; 
    NS_ADDREF(*result);
    return NS_OK;
}

////////////////////////////////////////////////////////////////////////////////