org.xmlvm.proc.NativeResourceLoader Maven / Gradle / Ivy
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/* Copyright (c) 2002-2011 by XMLVM.org
*
* Project Info: http://www.xmlvm.org
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or
* (at your option) any later version.
*
* This library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
* USA.
*/
package org.xmlvm.proc;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.xmlvm.Log;
import org.xmlvm.util.universalfile.UniversalFile;
/**
* Loads native methods for certain types.
*
* Background: We can cross compile the byte code of classes, but some classes
* have native methods, which are implemented elsewhere. For these, we generate
* native skeletons first and then implement those native methods manually.
* Whenever a type with native methods is loaded, the file that contains its
* native methods also needs to be loaded. This class simply looks up whether a
* given type has a native part. If so, it loads the file.
*/
public class NativeResourceLoader
{
private static final String TAG= NativeResourceLoader.class.getSimpleName();
private static final String NATIVE_PREFIX= "native_";
private final UniversalFile basePath;
private final String fileSuffix;
private Map cache;
/**
* Instantiates the native resource loader.
*
* @param basePath
* The path in which the native files can be found.
* @param fileSuffix
* The suffix of the native files (e.g. 'c').
*/
public NativeResourceLoader(UniversalFile basePath, String fileSuffix)
{
this.basePath= basePath;
this.fileSuffix= fileSuffix;
}
/**
* Returns a list with native implementations of all the types that do have
* native parts.
*
* @param typeNames
* a type name like "java.lang.Object" or "java_lang_Object".
*/
public List load(Set typeNames)
{
List result= new ArrayList();
if (!basePath.exists())
{
Log.error(TAG, "Could not find path: " + basePath.getAbsolutePath());
return result;
}
maybeInitialize();
for (String typeName : typeNames)
{
String fileName= typeNameToNativeFileName(typeName);
if (cache.containsKey(fileName))
{
result.add(cache.get(fileName));
}
}
return result;
}
/**
* Reads the files from the {@link #basePath} and makes them accessible in
* {@link #cache}. Does nothing, if {@link #cache} already exists.
*/
private void maybeInitialize()
{
if (cache != null)
{
return;
}
cache= new HashMap();
for (UniversalFile file : basePath.listFiles())
{
cache.put(file.getName(), file);
}
}
/**
* Returns the file name for the given type.
*
* @param typeName
* Type name like "java.lang.Object".
* @return File name like "native_java_lang_Object.c".
*/
private String typeNameToNativeFileName(String typeName)
{
typeName= typeName.replace('.', '_').replace('$', '_');
return NATIVE_PREFIX + typeName + "." + fileSuffix;
}
}