| /* |
| * Copyright (c) 2004, 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 |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.jvmstat.perfdata.monitor; |
| |
| import sun.jvmstat.monitor.*; |
| import java.nio.ByteOrder; |
| import java.nio.ByteBuffer; |
| import java.nio.IntBuffer; |
| |
| /** |
| * Abstraction representing the HotSpot PerfData instrumentation buffer |
| * header. This class represents only the fixed portion of the header. |
| * Version specific classes represent the portion of the header that |
| * may change from release to release. |
| * <p> |
| * The PerfDataBufferProlog class supports parsing of the following |
| * C structure: |
| * <pre> |
| * typedef struct { |
| * jint magic; // magic number - 0xcafec0c0 |
| * jbyte byte_order; // byte order of the buffer |
| * jbyte major_version; // major and minor version numbers |
| * jbyte minor_version; |
| * jbyte reserved_byte1; // reserved - see concrete implementations for |
| * // possible definition. |
| * ... // remainder is handled by the subclasses. |
| * } PerfDataPrologue |
| * </pre> |
| * |
| * @author Brian Doherty |
| * @since 1.5 |
| */ |
| public abstract class AbstractPerfDataBufferPrologue { |
| |
| protected ByteBuffer byteBuffer; |
| |
| /* |
| * the following constants must match the field offsets and sizes |
| * in the PerfDataPrologue structure in perfMemory.hpp |
| */ |
| final static int PERFDATA_PROLOG_OFFSET=0; |
| final static int PERFDATA_PROLOG_MAGIC_OFFSET=0; |
| final static int PERFDATA_PROLOG_BYTEORDER_OFFSET=4; |
| final static int PERFDATA_PROLOG_BYTEORDER_SIZE=1; // sizeof(byte) |
| final static int PERFDATA_PROLOG_MAJOR_OFFSET=5; |
| final static int PERFDATA_PROLOG_MAJOR_SIZE=1; // sizeof(byte) |
| final static int PERFDATA_PROLOG_MINOR_OFFSET=6; |
| final static int PERFDATA_PROLOG_MINOR_SIZE=1; // sizeof(byte) |
| final static int PERFDATA_PROLOG_RESERVEDB1_OFFSET=7; |
| final static int PERFDATA_PROLOG_RESERVEDB1_SIZE=1; // sizeof(byte) |
| |
| final static int PERFDATA_PROLOG_SIZE=8; // sizeof(struct PerfDataProlog) |
| |
| // these constants should match their #define counterparts in perfMemory.hpp |
| final static byte PERFDATA_BIG_ENDIAN=0; |
| final static byte PERFDATA_LITTLE_ENDIAN=1; |
| final static int PERFDATA_MAGIC = 0xcafec0c0; |
| |
| // names for counters that expose the prolog fields |
| public final static String PERFDATA_MAJOR_NAME = |
| "sun.perfdata.majorVersion"; |
| public final static String PERFDATA_MINOR_NAME = |
| "sun.perfdata.minorVersion"; |
| |
| /** |
| * Construct a PerfDataBufferPrologue instance. |
| * |
| * @param byteBuffer buffer containing the instrumentation data |
| */ |
| public AbstractPerfDataBufferPrologue(ByteBuffer byteBuffer) |
| throws MonitorException { |
| this.byteBuffer = byteBuffer.duplicate(); |
| |
| // the magic number is always stored in big-endian format |
| if (getMagic() != PERFDATA_MAGIC) { |
| throw new MonitorVersionException( |
| "Bad Magic: " + Integer.toHexString(getMagic())); |
| } |
| |
| // set the byte order |
| this.byteBuffer.order(getByteOrder()); |
| } |
| |
| /** |
| * Get the magic number. |
| * |
| * @return int - the magic number |
| */ |
| public int getMagic() { |
| // the magic number is always stored in big-endian format |
| ByteOrder order = byteBuffer.order(); |
| byteBuffer.order(ByteOrder.BIG_ENDIAN); |
| |
| // get the magic number |
| byteBuffer.position(PERFDATA_PROLOG_MAGIC_OFFSET); |
| int magic = byteBuffer.getInt(); |
| |
| // restore the byte order |
| byteBuffer.order(order); |
| return magic; |
| } |
| |
| /** |
| * Get the byte order. |
| * |
| * @return int - the byte order of the instrumentation buffer |
| */ |
| public ByteOrder getByteOrder() { |
| // byte order field is byte order independent |
| byteBuffer.position(PERFDATA_PROLOG_BYTEORDER_OFFSET); |
| |
| byte byte_order = byteBuffer.get(); |
| |
| if (byte_order == PERFDATA_BIG_ENDIAN) { |
| return ByteOrder.BIG_ENDIAN; |
| } else { |
| return ByteOrder.LITTLE_ENDIAN; |
| } |
| } |
| |
| /** |
| * Get the major version. |
| * |
| * @return int - the major version |
| */ |
| public int getMajorVersion() { |
| // major version field is byte order independent |
| byteBuffer.position(PERFDATA_PROLOG_MAJOR_OFFSET); |
| return (int)byteBuffer.get(); |
| } |
| |
| /** |
| * Get the minor version. |
| * |
| * @return int - the minor version |
| */ |
| public int getMinorVersion() { |
| // minor version field is byte order independent |
| byteBuffer.position(PERFDATA_PROLOG_MINOR_OFFSET); |
| return (int)byteBuffer.get(); |
| } |
| |
| /** |
| * Get the accessible flag. If supported, it indicates that the shared |
| * memory region is sufficiently initialized for client acccess. |
| * |
| * @return boolean - the initialized status |
| * @see #supportsAccessible() |
| */ |
| public abstract boolean isAccessible(); |
| |
| /** |
| * Test if the accessible flag is supported by this version of |
| * the PerfDataBufferPrologue. Although not an abstract method, this |
| * method should be overridden by version specific subclasses. |
| * |
| * @return boolean - the initialized flag support status. |
| * @see #isAccessible() |
| */ |
| public abstract boolean supportsAccessible(); |
| |
| /** |
| * Get the size of the header portion of the instrumentation buffer. |
| * |
| * @return int - the size of the header |
| */ |
| public int getSize() { |
| return PERFDATA_PROLOG_SIZE; // sizeof(struct PerfDataProlog) |
| } |
| |
| /** |
| * Return an IntBuffer that accesses the major version number. |
| * This is used to create a Monitor object for this value. |
| * |
| * @return IntBuffer - a ByteBuffer that accesses the major version number |
| * in the instrumentation buffer header. |
| */ |
| public IntBuffer majorVersionBuffer() { |
| int[] holder = new int[1]; |
| holder[0] = getMajorVersion(); |
| IntBuffer ib = IntBuffer.wrap(holder); |
| ib.limit(1); |
| return ib; |
| } |
| |
| /** |
| * Return an IntBuffer that accesses the minor version number. |
| * This is used to create a Monitor object for this value. |
| * |
| * @return IntBuffer - a ByteBuffer that accesses the minor version number |
| * in the instrumentation buffer header. |
| */ |
| public IntBuffer minorVersionBuffer() { |
| int[] holder = new int[1]; |
| holder[0] = getMinorVersion(); |
| IntBuffer ib = IntBuffer.wrap(holder); |
| ib.limit(1); |
| return ib; |
| } |
| |
| /** |
| * Get the magic number from the given byteBuffer. |
| * |
| * @return int - the magic number |
| */ |
| public static int getMagic(ByteBuffer bb) { |
| // save buffer state |
| int position = bb.position(); |
| ByteOrder order = bb.order(); |
| |
| // the magic number is always stored in big-endian format |
| bb.order(ByteOrder.BIG_ENDIAN); |
| bb.position(PERFDATA_PROLOG_MAGIC_OFFSET); |
| int magic = bb.getInt(); |
| |
| // restore buffer state. |
| bb.order(order); |
| bb.position(position); |
| |
| return magic; |
| } |
| |
| /** |
| * Get the major version number from the given ByteBuffer. |
| * |
| * @return int - the major version |
| */ |
| public static int getMajorVersion(ByteBuffer bb) { |
| // save buffer state |
| int position = bb.position(); |
| |
| bb.position(PERFDATA_PROLOG_MAJOR_OFFSET); |
| int major = (int) bb.get(); |
| |
| // restore buffer state. |
| bb.position(position); |
| |
| return major; |
| } |
| |
| /** |
| * Get the minor version number from the given ByteBuffer. |
| * |
| * @return int - the minor version |
| */ |
| public static int getMinorVersion(ByteBuffer bb) { |
| // save buffer state |
| int position = bb.position(); |
| |
| bb.position(PERFDATA_PROLOG_MINOR_OFFSET); |
| int minor = (int)bb.get(); |
| |
| // restore buffer state. |
| bb.position(position); |
| |
| return minor; |
| } |
| |
| /** |
| * Get the byte order for the given ByteBuffer. |
| * |
| * @return int - the byte order of the instrumentation buffer |
| */ |
| public static ByteOrder getByteOrder(ByteBuffer bb) { |
| // save buffer state |
| int position = bb.position(); |
| |
| bb.position(PERFDATA_PROLOG_BYTEORDER_OFFSET); |
| ByteOrder order = (bb.get() == PERFDATA_BIG_ENDIAN) |
| ? ByteOrder.BIG_ENDIAN |
| : ByteOrder.LITTLE_ENDIAN; |
| |
| // restore buffer state. |
| bb.position(position); |
| return order; |
| } |
| } |