BaseNativeType.java
/*
** Module : BaseNativeType.java
** Abstract : descriptor for a native function's argument or return value
**
** Copyright (c) 2013-2017, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description---------------------------------
** 001 GES 20131211 First version.
** 002 GES 20140127 Fixed out of order memory buffer delete in restore().
*/
/*
** This program is free software: you can redistribute it and/or modify
** it under the terms of the GNU Affero General Public License as
** published by the Free Software Foundation, either version 3 of the
** License, or (at your option) any later version.
**
** This program 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 Affero General Public License for more details.
**
** You may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
**
** Additional terms under GNU Affero GPL version 3 section 7:
**
** Under Section 7 of the GNU Affero GPL version 3, the following additional
** terms apply to the works covered under the License. These additional terms
** are non-permissive additional terms allowed under Section 7 of the GNU
** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
** You must preserve all legal notices or author attributions in the covered
** work or Appropriate Legal Notices displayed by works containing the covered
** work. You may not remove from the covered work any author or developer
** credit already included within the covered work.
**
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**
** This license does not grant any license or rights to use the trademarks
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** attribution required in this license.
*/
package com.goldencode.p2j.library;
import java.io.*;
import com.goldencode.p2j.util.*;
/**
* Descriptor for a native function's argument or return value.
*/
public abstract class BaseNativeType
implements Externalizable
{
/** Flag to control whether this element should be copied TO the native function. */
protected boolean copyIn = false;
/** Flag to control whether this element should be copied BACK FROM the native function. */
protected boolean copyOut = false;
/** Flag to control whether this element should be passed as a pointer. */
protected boolean passByPointer = false;
/** Data type of the instance (defined as a {@link LibraryManager} constant). */
protected int type = -1;
/** On the client side, this is used to render the data into native memory. */
protected memptr ref = null;
/** On the client side, this is used to render the data as a pointer. */
protected memptr ptr = null;
/**
* Default constructor.
*/
public BaseNativeType()
{
}
/**
* Reports whether this element should be copied TO the native function.
*
* @return <code>true</code> for INPUT and INPUT-OUTPUT parameters, <code>false</code>
* otherwise.
*/
public boolean isCopyIn()
{
return copyIn;
}
/**
* Assigns the flag for whether this element should be copied TO the native function.
*
* @param copyIn
* <code>true</code> for INPUT and INPUT-OUTPUT parameters, <code>false</code>
* otherwise.
*/
public void setCopyIn(boolean copyIn)
{
this.copyIn = copyIn;
}
/**
* Reports whether this element should be copied BACK FROM the native function.
*
* @return <code>true</code> for OUTPUT and RETURN parameters, <code>false</code>
* otherwise.
*/
public boolean isCopyOut()
{
return copyOut;
}
/**
* Assigns the flag for whether this element should be copied BACK FROM the native function.
*
* @param copyOut
* <code>true</code> for OUTPUT and RETURN parameters, <code>false</code>
* otherwise.
*/
public void setCopyOut(boolean copyOut)
{
this.copyOut = copyOut;
}
/**
* Reports whether the argument passed should be a pointer to the data element or whether the
* data should be passed by value to the native function.
*
* @return The stored value of the flag.
*/
public boolean isPassByPointer()
{
return passByPointer;
}
/**
* Assigns the flag for whether the argument passed should be a pointer to the data element or
* whether the data should be passed by value to the native function.
*
* @param passByPointer
* The new value of the flag.
*/
public void setPassByPointer(boolean passByPointer)
{
this.passByPointer = passByPointer;
}
/**
* Allocate native memory and render the data into that memory. If the instance requires
* copying data back from native memory or must be forced into passing by pointer, then
* this method will return back the address that contains the address of the memory in
* which the data is rendered.
* <p>
* This should never be called on the server, only on the client side.
*
* @return The memory address of the rendered data or 0 if there is no data to
* output.
*/
public long render()
{
long addr = render(0);
if (copyOut || passByPointer)
{
int sz = LibraryManager.ptrSize();
ptr = new memptr();
ptr.setLength(sz);
if (sz == 4)
{
ptr.setLong(addr, 1);
}
else
{
ptr.setInt64(addr, 1);
}
addr = ptr.getPointerValue().longValue();
}
return addr;
}
/**
* Copy back (if necessary) data from the native memory and deallocate the memory.
* <p>
* This should never be called on the server, only on the client side.
*/
public void restore()
{
long addr = 0;
if (ptr != null)
{
addr = ptr.getPointerValue().longValue();
}
restore(addr);
if (ptr != null)
{
ptr.setLength(0);
ptr = null;
}
}
/**
* Manually override the data type of the instance.
*
* @param type
* A {@link LibraryManager} constant representing the data type.
*/
public void setType(int type)
{
this.type = type;
}
/**
* Report the data type of the instance.
*
* @return A {@link LibraryManager} constant representing the data type.
*/
public int type()
{
return (copyOut || passByPointer) ? LibraryManager.TYPE_POINTER : type;
}
/**
* Report the size (in bytes) of the native memory needed to store this instance.
* <p>
* This should never be called on the server, only on the client side.
*
* @return The number of bytes needed.
*/
public abstract int size();
/**
* Render the data into native memory, which will be allocated if the address is not
* given.
* <p>
* This should never be called on the server, only on the client side.
*
* @param addr
* The memory address to which the data should be rendered, if the caller
* is supplying a buffer or 0 if the buffer should be allocated.
*
* @return The memory address of the rendered data or 0 if there is no data to
* output.
*/
public abstract long render(long addr);
/**
* Copy back (if necessary) data from the native memory and deallocate the memory.
* <p>
* This should never be called on the server, only on the client side.
*
* @param addr
* The memory address from which the data should be restored, if the caller
* is supplying a buffer or 0 if the buffer should already exist.
*/
public abstract void restore(long addr);
/**
* Replacement for the default object reading method. The latest
* state is read from the input source. The parent's state is
* read first.
*
* @param in
* The input source from which fields will be restored.
*
* @throws IOException
* In case of I/O errors.
* @throws ClassNotFoundException
* If payload can't be instantiated.
*/
public void readExternal(ObjectInput in)
throws IOException,
ClassNotFoundException
{
copyIn = in.readBoolean();
copyOut = in.readBoolean();
passByPointer = in.readBoolean();
// the memptr is only used on the client side and it is never transferred
// over the network
}
/**
* Replacement for the default object writing method. The latest
* state is written to the output destination. The parent's state is
* written first.
*
* @param out
* The output destination to which fields will be saved.
*
* @throws IOException
* In case of I/O errors.
*/
public void writeExternal(ObjectOutput out)
throws IOException
{
out.writeBoolean(copyIn);
out.writeBoolean(copyOut);
out.writeBoolean(passByPointer);
// the memptr is only used on the client side and it is never transferred
// over the network
}
}