| /* |
| * Copyright (c) 2000, 2009, 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.misc; |
| |
| import java.security.*; |
| import java.lang.reflect.*; |
| |
| import sun.reflect.CallerSensitive; |
| import sun.reflect.Reflection; |
| |
| |
| /** |
| * A collection of methods for performing low-level, unsafe operations. |
| * Although the class and all methods are public, use of this class is |
| * limited because only trusted code can obtain instances of it. |
| * |
| * @author John R. Rose |
| * @see #getUnsafe |
| */ |
| |
| public final class Unsafe { |
| |
| private static native void registerNatives(); |
| static { |
| registerNatives(); |
| sun.reflect.Reflection.registerMethodsToFilter(Unsafe.class, "getUnsafe"); |
| } |
| |
| private Unsafe() {} |
| |
| private static final Unsafe theUnsafe = new Unsafe(); |
| |
| /** |
| * Provides the caller with the capability of performing unsafe |
| * operations. |
| * |
| * <p> The returned <code>Unsafe</code> object should be carefully guarded |
| * by the caller, since it can be used to read and write data at arbitrary |
| * memory addresses. It must never be passed to untrusted code. |
| * |
| * <p> Most methods in this class are very low-level, and correspond to a |
| * small number of hardware instructions (on typical machines). Compilers |
| * are encouraged to optimize these methods accordingly. |
| * |
| * <p> Here is a suggested idiom for using unsafe operations: |
| * |
| * <blockquote><pre> |
| * class MyTrustedClass { |
| * private static final Unsafe unsafe = Unsafe.getUnsafe(); |
| * ... |
| * private long myCountAddress = ...; |
| * public int getCount() { return unsafe.getByte(myCountAddress); } |
| * } |
| * </pre></blockquote> |
| * |
| * (It may assist compilers to make the local variable be |
| * <code>final</code>.) |
| * |
| * @exception SecurityException if a security manager exists and its |
| * <code>checkPropertiesAccess</code> method doesn't allow |
| * access to the system properties. |
| */ |
| @CallerSensitive |
| public static Unsafe getUnsafe() { |
| Class cc = Reflection.getCallerClass(); |
| if (cc.getClassLoader() != null) |
| throw new SecurityException("Unsafe"); |
| return theUnsafe; |
| } |
| |
| /// peek and poke operations |
| /// (compilers should optimize these to memory ops) |
| |
| // These work on object fields in the Java heap. |
| // They will not work on elements of packed arrays. |
| |
| /** |
| * Fetches a value from a given Java variable. |
| * More specifically, fetches a field or array element within the given |
| * object <code>o</code> at the given offset, or (if <code>o</code> is |
| * null) from the memory address whose numerical value is the given |
| * offset. |
| * <p> |
| * The results are undefined unless one of the following cases is true: |
| * <ul> |
| * <li>The offset was obtained from {@link #objectFieldOffset} on |
| * the {@link java.lang.reflect.Field} of some Java field and the object |
| * referred to by <code>o</code> is of a class compatible with that |
| * field's class. |
| * |
| * <li>The offset and object reference <code>o</code> (either null or |
| * non-null) were both obtained via {@link #staticFieldOffset} |
| * and {@link #staticFieldBase} (respectively) from the |
| * reflective {@link Field} representation of some Java field. |
| * |
| * <li>The object referred to by <code>o</code> is an array, and the offset |
| * is an integer of the form <code>B+N*S</code>, where <code>N</code> is |
| * a valid index into the array, and <code>B</code> and <code>S</code> are |
| * the values obtained by {@link #arrayBaseOffset} and {@link |
| * #arrayIndexScale} (respectively) from the array's class. The value |
| * referred to is the <code>N</code><em>th</em> element of the array. |
| * |
| * </ul> |
| * <p> |
| * If one of the above cases is true, the call references a specific Java |
| * variable (field or array element). However, the results are undefined |
| * if that variable is not in fact of the type returned by this method. |
| * <p> |
| * This method refers to a variable by means of two parameters, and so |
| * it provides (in effect) a <em>double-register</em> addressing mode |
| * for Java variables. When the object reference is null, this method |
| * uses its offset as an absolute address. This is similar in operation |
| * to methods such as {@link #getInt(long)}, which provide (in effect) a |
| * <em>single-register</em> addressing mode for non-Java variables. |
| * However, because Java variables may have a different layout in memory |
| * from non-Java variables, programmers should not assume that these |
| * two addressing modes are ever equivalent. Also, programmers should |
| * remember that offsets from the double-register addressing mode cannot |
| * be portably confused with longs used in the single-register addressing |
| * mode. |
| * |
| * @param o Java heap object in which the variable resides, if any, else |
| * null |
| * @param offset indication of where the variable resides in a Java heap |
| * object, if any, else a memory address locating the variable |
| * statically |
| * @return the value fetched from the indicated Java variable |
| * @throws RuntimeException No defined exceptions are thrown, not even |
| * {@link NullPointerException} |
| */ |
| public native int getInt(Object o, long offset); |
| |
| /** |
| * Stores a value into a given Java variable. |
| * <p> |
| * The first two parameters are interpreted exactly as with |
| * {@link #getInt(Object, long)} to refer to a specific |
| * Java variable (field or array element). The given value |
| * is stored into that variable. |
| * <p> |
| * The variable must be of the same type as the method |
| * parameter <code>x</code>. |
| * |
| * @param o Java heap object in which the variable resides, if any, else |
| * null |
| * @param offset indication of where the variable resides in a Java heap |
| * object, if any, else a memory address locating the variable |
| * statically |
| * @param x the value to store into the indicated Java variable |
| * @throws RuntimeException No defined exceptions are thrown, not even |
| * {@link NullPointerException} |
| */ |
| public native void putInt(Object o, long offset, int x); |
| |
| /** |
| * Fetches a reference value from a given Java variable. |
| * @see #getInt(Object, long) |
| */ |
| public native Object getObject(Object o, long offset); |
| |
| /** |
| * Stores a reference value into a given Java variable. |
| * <p> |
| * Unless the reference <code>x</code> being stored is either null |
| * or matches the field type, the results are undefined. |
| * If the reference <code>o</code> is non-null, car marks or |
| * other store barriers for that object (if the VM requires them) |
| * are updated. |
| * @see #putInt(Object, int, int) |
| */ |
| public native void putObject(Object o, long offset, Object x); |
| |
| /** @see #getInt(Object, long) */ |
| public native boolean getBoolean(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putBoolean(Object o, long offset, boolean x); |
| /** @see #getInt(Object, long) */ |
| public native byte getByte(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putByte(Object o, long offset, byte x); |
| /** @see #getInt(Object, long) */ |
| public native short getShort(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putShort(Object o, long offset, short x); |
| /** @see #getInt(Object, long) */ |
| public native char getChar(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putChar(Object o, long offset, char x); |
| /** @see #getInt(Object, long) */ |
| public native long getLong(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putLong(Object o, long offset, long x); |
| /** @see #getInt(Object, long) */ |
| public native float getFloat(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putFloat(Object o, long offset, float x); |
| /** @see #getInt(Object, long) */ |
| public native double getDouble(Object o, long offset); |
| /** @see #putInt(Object, int, int) */ |
| public native void putDouble(Object o, long offset, double x); |
| |
| /** |
| * This method, like all others with 32-bit offsets, was native |
| * in a previous release but is now a wrapper which simply casts |
| * the offset to a long value. It provides backward compatibility |
| * with bytecodes compiled against 1.4. |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public int getInt(Object o, int offset) { |
| return getInt(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putInt(Object o, int offset, int x) { |
| putInt(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public Object getObject(Object o, int offset) { |
| return getObject(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putObject(Object o, int offset, Object x) { |
| putObject(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public boolean getBoolean(Object o, int offset) { |
| return getBoolean(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putBoolean(Object o, int offset, boolean x) { |
| putBoolean(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public byte getByte(Object o, int offset) { |
| return getByte(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putByte(Object o, int offset, byte x) { |
| putByte(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public short getShort(Object o, int offset) { |
| return getShort(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putShort(Object o, int offset, short x) { |
| putShort(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public char getChar(Object o, int offset) { |
| return getChar(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putChar(Object o, int offset, char x) { |
| putChar(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public long getLong(Object o, int offset) { |
| return getLong(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putLong(Object o, int offset, long x) { |
| putLong(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public float getFloat(Object o, int offset) { |
| return getFloat(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putFloat(Object o, int offset, float x) { |
| putFloat(o, (long)offset, x); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public double getDouble(Object o, int offset) { |
| return getDouble(o, (long)offset); |
| } |
| |
| /** |
| * @deprecated As of 1.4.1, cast the 32-bit offset argument to a long. |
| * See {@link #staticFieldOffset}. |
| */ |
| @Deprecated |
| public void putDouble(Object o, int offset, double x) { |
| putDouble(o, (long)offset, x); |
| } |
| |
| // These work on values in the C heap. |
| |
| /** |
| * Fetches a value from a given memory address. If the address is zero, or |
| * does not point into a block obtained from {@link #allocateMemory}, the |
| * results are undefined. |
| * |
| * @see #allocateMemory |
| */ |
| public native byte getByte(long address); |
| |
| /** |
| * Stores a value into a given memory address. If the address is zero, or |
| * does not point into a block obtained from {@link #allocateMemory}, the |
| * results are undefined. |
| * |
| * @see #getByte(long) |
| */ |
| public native void putByte(long address, byte x); |
| |
| /** @see #getByte(long) */ |
| public native short getShort(long address); |
| /** @see #putByte(long, byte) */ |
| public native void putShort(long address, short x); |
| /** @see #getByte(long) */ |
| public native char getChar(long address); |
| /** @see #putByte(long, byte) */ |
| public native void putChar(long address, char x); |
| /** @see #getByte(long) */ |
| public native int getInt(long address); |
| /** @see #putByte(long, byte) */ |
| public native void putInt(long address, int x); |
| /** @see #getByte(long) */ |
| public native long getLong(long address); |
| /** @see #putByte(long, byte) */ |
| public native void putLong(long address, long x); |
| /** @see #getByte(long) */ |
| public native float getFloat(long address); |
| /** @see #putByte(long, byte) */ |
| public native void putFloat(long address, float x); |
| /** @see #getByte(long) */ |
| public native double getDouble(long address); |
| /** @see #putByte(long, byte) */ |
| public native void putDouble(long address, double x); |
| |
| /** |
| * Fetches a native pointer from a given memory address. If the address is |
| * zero, or does not point into a block obtained from {@link |
| * #allocateMemory}, the results are undefined. |
| * |
| * <p> If the native pointer is less than 64 bits wide, it is extended as |
| * an unsigned number to a Java long. The pointer may be indexed by any |
| * given byte offset, simply by adding that offset (as a simple integer) to |
| * the long representing the pointer. The number of bytes actually read |
| * from the target address maybe determined by consulting {@link |
| * #addressSize}. |
| * |
| * @see #allocateMemory |
| */ |
| public native long getAddress(long address); |
| |
| /** |
| * Stores a native pointer into a given memory address. If the address is |
| * zero, or does not point into a block obtained from {@link |
| * #allocateMemory}, the results are undefined. |
| * |
| * <p> The number of bytes actually written at the target address maybe |
| * determined by consulting {@link #addressSize}. |
| * |
| * @see #getAddress(long) |
| */ |
| public native void putAddress(long address, long x); |
| |
| /// wrappers for malloc, realloc, free: |
| |
| /** |
| * Allocates a new block of native memory, of the given size in bytes. The |
| * contents of the memory are uninitialized; they will generally be |
| * garbage. The resulting native pointer will never be zero, and will be |
| * aligned for all value types. Dispose of this memory by calling {@link |
| * #freeMemory}, or resize it with {@link #reallocateMemory}. |
| * |
| * @throws IllegalArgumentException if the size is negative or too large |
| * for the native size_t type |
| * |
| * @throws OutOfMemoryError if the allocation is refused by the system |
| * |
| * @see #getByte(long) |
| * @see #putByte(long, byte) |
| */ |
| public native long allocateMemory(long bytes); |
| |
| /** |
| * Resizes a new block of native memory, to the given size in bytes. The |
| * contents of the new block past the size of the old block are |
| * uninitialized; they will generally be garbage. The resulting native |
| * pointer will be zero if and only if the requested size is zero. The |
| * resulting native pointer will be aligned for all value types. Dispose |
| * of this memory by calling {@link #freeMemory}, or resize it with {@link |
| * #reallocateMemory}. The address passed to this method may be null, in |
| * which case an allocation will be performed. |
| * |
| * @throws IllegalArgumentException if the size is negative or too large |
| * for the native size_t type |
| * |
| * @throws OutOfMemoryError if the allocation is refused by the system |
| * |
| * @see #allocateMemory |
| */ |
| public native long reallocateMemory(long address, long bytes); |
| |
| /** |
| * Sets all bytes in a given block of memory to a fixed value |
| * (usually zero). |
| * |
| * <p>This method determines a block's base address by means of two parameters, |
| * and so it provides (in effect) a <em>double-register</em> addressing mode, |
| * as discussed in {@link #getInt(Object,long)}. When the object reference is null, |
| * the offset supplies an absolute base address. |
| * |
| * <p>The stores are in coherent (atomic) units of a size determined |
| * by the address and length parameters. If the effective address and |
| * length are all even modulo 8, the stores take place in 'long' units. |
| * If the effective address and length are (resp.) even modulo 4 or 2, |
| * the stores take place in units of 'int' or 'short'. |
| * |
| * @since 1.7 |
| */ |
| public native void setMemory(Object o, long offset, long bytes, byte value); |
| |
| /** |
| * Sets all bytes in a given block of memory to a fixed value |
| * (usually zero). This provides a <em>single-register</em> addressing mode, |
| * as discussed in {@link #getInt(Object,long)}. |
| * |
| * <p>Equivalent to <code>setMemory(null, address, bytes, value)</code>. |
| */ |
| public void setMemory(long address, long bytes, byte value) { |
| setMemory(null, address, bytes, value); |
| } |
| |
| /** |
| * Sets all bytes in a given block of memory to a copy of another |
| * block. |
| * |
| * <p>This method determines each block's base address by means of two parameters, |
| * and so it provides (in effect) a <em>double-register</em> addressing mode, |
| * as discussed in {@link #getInt(Object,long)}. When the object reference is null, |
| * the offset supplies an absolute base address. |
| * |
| * <p>The transfers are in coherent (atomic) units of a size determined |
| * by the address and length parameters. If the effective addresses and |
| * length are all even modulo 8, the transfer takes place in 'long' units. |
| * If the effective addresses and length are (resp.) even modulo 4 or 2, |
| * the transfer takes place in units of 'int' or 'short'. |
| * |
| * @since 1.7 |
| */ |
| public native void copyMemory(Object srcBase, long srcOffset, |
| Object destBase, long destOffset, |
| long bytes); |
| /** |
| * Sets all bytes in a given block of memory to a copy of another |
| * block. This provides a <em>single-register</em> addressing mode, |
| * as discussed in {@link #getInt(Object,long)}. |
| * |
| * Equivalent to <code>copyMemory(null, srcAddress, null, destAddress, bytes)</code>. |
| */ |
| public void copyMemory(long srcAddress, long destAddress, long bytes) { |
| copyMemory(null, srcAddress, null, destAddress, bytes); |
| } |
| |
| /** |
| * Disposes of a block of native memory, as obtained from {@link |
| * #allocateMemory} or {@link #reallocateMemory}. The address passed to |
| * this method may be null, in which case no action is taken. |
| * |
| * @see #allocateMemory |
| */ |
| public native void freeMemory(long address); |
| |
| /// random queries |
| |
| /** |
| * This constant differs from all results that will ever be returned from |
| * {@link #staticFieldOffset}, {@link #objectFieldOffset}, |
| * or {@link #arrayBaseOffset}. |
| */ |
| public static final int INVALID_FIELD_OFFSET = -1; |
| |
| /** |
| * Returns the offset of a field, truncated to 32 bits. |
| * This method is implemented as follows: |
| * <blockquote><pre> |
| * public int fieldOffset(Field f) { |
| * if (Modifier.isStatic(f.getModifiers())) |
| * return (int) staticFieldOffset(f); |
| * else |
| * return (int) objectFieldOffset(f); |
| * } |
| * </pre></blockquote> |
| * @deprecated As of 1.4.1, use {@link #staticFieldOffset} for static |
| * fields and {@link #objectFieldOffset} for non-static fields. |
| */ |
| @Deprecated |
| public int fieldOffset(Field f) { |
| if (Modifier.isStatic(f.getModifiers())) |
| return (int) staticFieldOffset(f); |
| else |
| return (int) objectFieldOffset(f); |
| } |
| |
| /** |
| * Returns the base address for accessing some static field |
| * in the given class. This method is implemented as follows: |
| * <blockquote><pre> |
| * public Object staticFieldBase(Class c) { |
| * Field[] fields = c.getDeclaredFields(); |
| * for (int i = 0; i < fields.length; i++) { |
| * if (Modifier.isStatic(fields[i].getModifiers())) { |
| * return staticFieldBase(fields[i]); |
| * } |
| * } |
| * return null; |
| * } |
| * </pre></blockquote> |
| * @deprecated As of 1.4.1, use {@link #staticFieldBase(Field)} |
| * to obtain the base pertaining to a specific {@link Field}. |
| * This method works only for JVMs which store all statics |
| * for a given class in one place. |
| */ |
| @Deprecated |
| public Object staticFieldBase(Class c) { |
| Field[] fields = c.getDeclaredFields(); |
| for (int i = 0; i < fields.length; i++) { |
| if (Modifier.isStatic(fields[i].getModifiers())) { |
| return staticFieldBase(fields[i]); |
| } |
| } |
| return null; |
| } |
| |
| /** |
| * Report the location of a given field in the storage allocation of its |
| * class. Do not expect to perform any sort of arithmetic on this offset; |
| * it is just a cookie which is passed to the unsafe heap memory accessors. |
| * |
| * <p>Any given field will always have the same offset and base, and no |
| * two distinct fields of the same class will ever have the same offset |
| * and base. |
| * |
| * <p>As of 1.4.1, offsets for fields are represented as long values, |
| * although the Sun JVM does not use the most significant 32 bits. |
| * However, JVM implementations which store static fields at absolute |
| * addresses can use long offsets and null base pointers to express |
| * the field locations in a form usable by {@link #getInt(Object,long)}. |
| * Therefore, code which will be ported to such JVMs on 64-bit platforms |
| * must preserve all bits of static field offsets. |
| * @see #getInt(Object, long) |
| */ |
| public native long staticFieldOffset(Field f); |
| |
| /** |
| * Report the location of a given static field, in conjunction with {@link |
| * #staticFieldBase}. |
| * <p>Do not expect to perform any sort of arithmetic on this offset; |
| * it is just a cookie which is passed to the unsafe heap memory accessors. |
| * |
| * <p>Any given field will always have the same offset, and no two distinct |
| * fields of the same class will ever have the same offset. |
| * |
| * <p>As of 1.4.1, offsets for fields are represented as long values, |
| * although the Sun JVM does not use the most significant 32 bits. |
| * It is hard to imagine a JVM technology which needs more than |
| * a few bits to encode an offset within a non-array object, |
| * However, for consistency with other methods in this class, |
| * this method reports its result as a long value. |
| * @see #getInt(Object, long) |
| */ |
| public native long objectFieldOffset(Field f); |
| |
| /** |
| * Report the location of a given static field, in conjunction with {@link |
| * #staticFieldOffset}. |
| * <p>Fetch the base "Object", if any, with which static fields of the |
| * given class can be accessed via methods like {@link #getInt(Object, |
| * long)}. This value may be null. This value may refer to an object |
| * which is a "cookie", not guaranteed to be a real Object, and it should |
| * not be used in any way except as argument to the get and put routines in |
| * this class. |
| */ |
| public native Object staticFieldBase(Field f); |
| |
| /** |
| * Detect if the given class may need to be initialized. This is often |
| * needed in conjunction with obtaining the static field base of a |
| * class. |
| * @return false only if a call to {@code ensureClassInitialized} would have no effect |
| */ |
| public native boolean shouldBeInitialized(Class<?> c); |
| |
| /** |
| * Ensure the given class has been initialized. This is often |
| * needed in conjunction with obtaining the static field base of a |
| * class. |
| */ |
| public native void ensureClassInitialized(Class c); |
| |
| /** |
| * Report the offset of the first element in the storage allocation of a |
| * given array class. If {@link #arrayIndexScale} returns a non-zero value |
| * for the same class, you may use that scale factor, together with this |
| * base offset, to form new offsets to access elements of arrays of the |
| * given class. |
| * |
| * @see #getInt(Object, long) |
| * @see #putInt(Object, long, int) |
| */ |
| public native int arrayBaseOffset(Class arrayClass); |
| |
| /** The value of {@code arrayBaseOffset(boolean[].class)} */ |
| public static final int ARRAY_BOOLEAN_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(boolean[].class); |
| |
| /** The value of {@code arrayBaseOffset(byte[].class)} */ |
| public static final int ARRAY_BYTE_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(byte[].class); |
| |
| /** The value of {@code arrayBaseOffset(short[].class)} */ |
| public static final int ARRAY_SHORT_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(short[].class); |
| |
| /** The value of {@code arrayBaseOffset(char[].class)} */ |
| public static final int ARRAY_CHAR_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(char[].class); |
| |
| /** The value of {@code arrayBaseOffset(int[].class)} */ |
| public static final int ARRAY_INT_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(int[].class); |
| |
| /** The value of {@code arrayBaseOffset(long[].class)} */ |
| public static final int ARRAY_LONG_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(long[].class); |
| |
| /** The value of {@code arrayBaseOffset(float[].class)} */ |
| public static final int ARRAY_FLOAT_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(float[].class); |
| |
| /** The value of {@code arrayBaseOffset(double[].class)} */ |
| public static final int ARRAY_DOUBLE_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(double[].class); |
| |
| /** The value of {@code arrayBaseOffset(Object[].class)} */ |
| public static final int ARRAY_OBJECT_BASE_OFFSET |
| = theUnsafe.arrayBaseOffset(Object[].class); |
| |
| /** |
| * Report the scale factor for addressing elements in the storage |
| * allocation of a given array class. However, arrays of "narrow" types |
| * will generally not work properly with accessors like {@link |
| * #getByte(Object, int)}, so the scale factor for such classes is reported |
| * as zero. |
| * |
| * @see #arrayBaseOffset |
| * @see #getInt(Object, long) |
| * @see #putInt(Object, long, int) |
| */ |
| public native int arrayIndexScale(Class arrayClass); |
| |
| /** The value of {@code arrayIndexScale(boolean[].class)} */ |
| public static final int ARRAY_BOOLEAN_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(boolean[].class); |
| |
| /** The value of {@code arrayIndexScale(byte[].class)} */ |
| public static final int ARRAY_BYTE_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(byte[].class); |
| |
| /** The value of {@code arrayIndexScale(short[].class)} */ |
| public static final int ARRAY_SHORT_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(short[].class); |
| |
| /** The value of {@code arrayIndexScale(char[].class)} */ |
| public static final int ARRAY_CHAR_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(char[].class); |
| |
| /** The value of {@code arrayIndexScale(int[].class)} */ |
| public static final int ARRAY_INT_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(int[].class); |
| |
| /** The value of {@code arrayIndexScale(long[].class)} */ |
| public static final int ARRAY_LONG_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(long[].class); |
| |
| /** The value of {@code arrayIndexScale(float[].class)} */ |
| public static final int ARRAY_FLOAT_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(float[].class); |
| |
| /** The value of {@code arrayIndexScale(double[].class)} */ |
| public static final int ARRAY_DOUBLE_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(double[].class); |
| |
| /** The value of {@code arrayIndexScale(Object[].class)} */ |
| public static final int ARRAY_OBJECT_INDEX_SCALE |
| = theUnsafe.arrayIndexScale(Object[].class); |
| |
| /** |
| * Report the size in bytes of a native pointer, as stored via {@link |
| * #putAddress}. This value will be either 4 or 8. Note that the sizes of |
| * other primitive types (as stored in native memory blocks) is determined |
| * fully by their information content. |
| */ |
| public native int addressSize(); |
| |
| /** The value of {@code addressSize()} */ |
| public static final int ADDRESS_SIZE = theUnsafe.addressSize(); |
| |
| /** |
| * Report the size in bytes of a native memory page (whatever that is). |
| * This value will always be a power of two. |
| */ |
| public native int pageSize(); |
| |
| |
| /// random trusted operations from JNI: |
| |
| /** |
| * Tell the VM to define a class, without security checks. By default, the |
| * class loader and protection domain come from the caller's class. |
| */ |
| public native Class defineClass(String name, byte[] b, int off, int len, |
| ClassLoader loader, |
| ProtectionDomain protectionDomain); |
| |
| /** |
| * @deprecated Use defineClass(String, byte[], int, int, ClassLoader, ProtectionDomain) |
| * instead. This method will be removed in JDK 8. |
| */ |
| @Deprecated |
| @CallerSensitive |
| public native Class defineClass(String name, byte[] b, int off, int len); |
| |
| /** |
| * Define a class but do not make it known to the class loader or system dictionary. |
| * <p> |
| * For each CP entry, the corresponding CP patch must either be null or have |
| * the a format that matches its tag: |
| * <ul> |
| * <li>Integer, Long, Float, Double: the corresponding wrapper object type from java.lang |
| * <li>Utf8: a string (must have suitable syntax if used as signature or name) |
| * <li>Class: any java.lang.Class object |
| * <li>String: any object (not just a java.lang.String) |
| * <li>InterfaceMethodRef: (NYI) a method handle to invoke on that call site's arguments |
| * </ul> |
| * @params hostClass context for linkage, access control, protection domain, and class loader |
| * @params data bytes of a class file |
| * @params cpPatches where non-null entries exist, they replace corresponding CP entries in data |
| */ |
| public native Class defineAnonymousClass(Class hostClass, byte[] data, Object[] cpPatches); |
| |
| |
| /** Allocate an instance but do not run any constructor. |
| Initializes the class if it has not yet been. */ |
| public native Object allocateInstance(Class cls) |
| throws InstantiationException; |
| |
| /** Lock the object. It must get unlocked via {@link #monitorExit}. */ |
| public native void monitorEnter(Object o); |
| |
| /** |
| * Unlock the object. It must have been locked via {@link |
| * #monitorEnter}. |
| */ |
| public native void monitorExit(Object o); |
| |
| /** |
| * Tries to lock the object. Returns true or false to indicate |
| * whether the lock succeeded. If it did, the object must be |
| * unlocked via {@link #monitorExit}. |
| */ |
| public native boolean tryMonitorEnter(Object o); |
| |
| /** Throw the exception without telling the verifier. */ |
| public native void throwException(Throwable ee); |
| |
| |
| /** |
| * Atomically update Java variable to <tt>x</tt> if it is currently |
| * holding <tt>expected</tt>. |
| * @return <tt>true</tt> if successful |
| */ |
| public final native boolean compareAndSwapObject(Object o, long offset, |
| Object expected, |
| Object x); |
| |
| /** |
| * Atomically update Java variable to <tt>x</tt> if it is currently |
| * holding <tt>expected</tt>. |
| * @return <tt>true</tt> if successful |
| */ |
| public final native boolean compareAndSwapInt(Object o, long offset, |
| int expected, |
| int x); |
| |
| /** |
| * Atomically update Java variable to <tt>x</tt> if it is currently |
| * holding <tt>expected</tt>. |
| * @return <tt>true</tt> if successful |
| */ |
| public final native boolean compareAndSwapLong(Object o, long offset, |
| long expected, |
| long x); |
| |
| /** |
| * Fetches a reference value from a given Java variable, with volatile |
| * load semantics. Otherwise identical to {@link #getObject(Object, long)} |
| */ |
| public native Object getObjectVolatile(Object o, long offset); |
| |
| /** |
| * Stores a reference value into a given Java variable, with |
| * volatile store semantics. Otherwise identical to {@link #putObject(Object, long, Object)} |
| */ |
| public native void putObjectVolatile(Object o, long offset, Object x); |
| |
| /** Volatile version of {@link #getInt(Object, long)} */ |
| public native int getIntVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putInt(Object, long, int)} */ |
| public native void putIntVolatile(Object o, long offset, int x); |
| |
| /** Volatile version of {@link #getBoolean(Object, long)} */ |
| public native boolean getBooleanVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putBoolean(Object, long, boolean)} */ |
| public native void putBooleanVolatile(Object o, long offset, boolean x); |
| |
| /** Volatile version of {@link #getByte(Object, long)} */ |
| public native byte getByteVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putByte(Object, long, byte)} */ |
| public native void putByteVolatile(Object o, long offset, byte x); |
| |
| /** Volatile version of {@link #getShort(Object, long)} */ |
| public native short getShortVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putShort(Object, long, short)} */ |
| public native void putShortVolatile(Object o, long offset, short x); |
| |
| /** Volatile version of {@link #getChar(Object, long)} */ |
| public native char getCharVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putChar(Object, long, char)} */ |
| public native void putCharVolatile(Object o, long offset, char x); |
| |
| /** Volatile version of {@link #getLong(Object, long)} */ |
| public native long getLongVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putLong(Object, long, long)} */ |
| public native void putLongVolatile(Object o, long offset, long x); |
| |
| /** Volatile version of {@link #getFloat(Object, long)} */ |
| public native float getFloatVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putFloat(Object, long, float)} */ |
| public native void putFloatVolatile(Object o, long offset, float x); |
| |
| /** Volatile version of {@link #getDouble(Object, long)} */ |
| public native double getDoubleVolatile(Object o, long offset); |
| |
| /** Volatile version of {@link #putDouble(Object, long, double)} */ |
| public native void putDoubleVolatile(Object o, long offset, double x); |
| |
| /** |
| * Version of {@link #putObjectVolatile(Object, long, Object)} |
| * that does not guarantee immediate visibility of the store to |
| * other threads. This method is generally only useful if the |
| * underlying field is a Java volatile (or if an array cell, one |
| * that is otherwise only accessed using volatile accesses). |
| */ |
| public native void putOrderedObject(Object o, long offset, Object x); |
| |
| /** Ordered/Lazy version of {@link #putIntVolatile(Object, long, int)} */ |
| public native void putOrderedInt(Object o, long offset, int x); |
| |
| /** Ordered/Lazy version of {@link #putLongVolatile(Object, long, long)} */ |
| public native void putOrderedLong(Object o, long offset, long x); |
| |
| /** |
| * Unblock the given thread blocked on <tt>park</tt>, or, if it is |
| * not blocked, cause the subsequent call to <tt>park</tt> not to |
| * block. Note: this operation is "unsafe" solely because the |
| * caller must somehow ensure that the thread has not been |
| * destroyed. Nothing special is usually required to ensure this |
| * when called from Java (in which there will ordinarily be a live |
| * reference to the thread) but this is not nearly-automatically |
| * so when calling from native code. |
| * @param thread the thread to unpark. |
| * |
| */ |
| public native void unpark(Object thread); |
| |
| /** |
| * Block current thread, returning when a balancing |
| * <tt>unpark</tt> occurs, or a balancing <tt>unpark</tt> has |
| * already occurred, or the thread is interrupted, or, if not |
| * absolute and time is not zero, the given time nanoseconds have |
| * elapsed, or if absolute, the given deadline in milliseconds |
| * since Epoch has passed, or spuriously (i.e., returning for no |
| * "reason"). Note: This operation is in the Unsafe class only |
| * because <tt>unpark</tt> is, so it would be strange to place it |
| * elsewhere. |
| */ |
| public native void park(boolean isAbsolute, long time); |
| |
| /** |
| * Gets the load average in the system run queue assigned |
| * to the available processors averaged over various periods of time. |
| * This method retrieves the given <tt>nelem</tt> samples and |
| * assigns to the elements of the given <tt>loadavg</tt> array. |
| * The system imposes a maximum of 3 samples, representing |
| * averages over the last 1, 5, and 15 minutes, respectively. |
| * |
| * @params loadavg an array of double of size nelems |
| * @params nelems the number of samples to be retrieved and |
| * must be 1 to 3. |
| * |
| * @return the number of samples actually retrieved; or -1 |
| * if the load average is unobtainable. |
| */ |
| public native int getLoadAverage(double[] loadavg, int nelems); |
| } |
