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 * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package org.graalvm.visualvm.lib.profiler.heapwalk.details.jdk;

import java.nio.charset.Charset;
import java.util.List;
import org.graalvm.visualvm.lib.jfluid.heap.Heap;
import org.graalvm.visualvm.lib.jfluid.heap.Instance;
import org.graalvm.visualvm.lib.profiler.heapwalk.details.spi.DetailsProvider;
import org.graalvm.visualvm.lib.profiler.heapwalk.details.spi.DetailsUtils;
import org.openide.util.lookup.ServiceProvider;

/**
 *
 * @author Tomas Hurka
 */
@ServiceProvider(service = DetailsProvider.class)
public final class NioDetailsProvider extends DetailsProvider.Basic {

    private static final String UNIXPATH_MASK = "sun.nio.fs.UnixPath"; // NOI18N
    private static final String WINDOWSPATH_MASK = "sun.nio.fs.WindowsPath+"; // NOI18N
    private static final String FCI_MASK = "sun.nio.ch.FileChannelImpl";        // NOI18N
    private static final String BUFFER_MASK = "java.nio.Buffer+";               // NOI18N
    private static final String HEAPCHARBUFFER_MASK = "java.nio.HeapCharBuffer";// NOI18N

    private long lastHeapId;
    private Charset lastJnuEncoding;

    public NioDetailsProvider() {
        super(UNIXPATH_MASK, WINDOWSPATH_MASK, FCI_MASK, BUFFER_MASK, HEAPCHARBUFFER_MASK);
    }

    public String getDetailsString(String className, Instance instance) {
        switch (className) {
            case UNIXPATH_MASK: {
                String path = DetailsUtils.getInstanceFieldString(instance, "stringValue");   // NOI18N
                if (path != null) {
                    return path;
                }   Charset encoding = getJnuEncoding(instance.getJavaClass().getHeap());
                List<String> pathItems = DetailsUtils.getPrimitiveArrayFieldValues(instance, "path");                  // NOI18N
                byte[] pathArr = DetailsUtils.getByteArray(pathItems);
                if (pathArr != null) {
                    return new String(pathArr, encoding);
                }
                break;
            }
            case WINDOWSPATH_MASK:
                return DetailsUtils.getInstanceFieldString(instance, "path");   // NOI18N
            case FCI_MASK: // FileChannelImpl
                return DetailsUtils.getInstanceFieldString(instance, "path"); // NOI18N
            case BUFFER_MASK: {
                int position = DetailsUtils.getIntFieldValue(instance, "position", -1); // NOI18N
                int limit = DetailsUtils.getIntFieldValue(instance, "limit", -1);       // NOI18N
                int capacity = DetailsUtils.getIntFieldValue(instance, "capacity", -1);       // NOI18N
                return String.format("[pos=%d lim=%d cap=%d]", position, limit, capacity); // NOI18N
            }
            case HEAPCHARBUFFER_MASK: {
                int position = DetailsUtils.getIntFieldValue(instance, "position", -1); // NOI18N
                int limit = DetailsUtils.getIntFieldValue(instance, "limit", -1);       // NOI18N
                int offset = DetailsUtils.getIntFieldValue(instance, "offset", -1);       // NOI18N
                return DetailsUtils.getPrimitiveArrayFieldString(instance, "hb", position + offset, limit - position, null, "..."); // NOI18N
            }
            default:
                break;
        }
        return null;
    }

    private Charset getJnuEncoding(Heap heap) {
        if (lastHeapId != System.identityHashCode(heap)) {
            String encoding = heap.getSystemProperties().getProperty("sun.jnu.encoding", "UTF-8"); // NOI18N
            lastJnuEncoding = Charset.forName(encoding);
            lastHeapId = System.identityHashCode(heap);
        }
        return lastJnuEncoding;
    }

}
