Copyright (c) 2004, 2015 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2004, 2015 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.osgi.storage.bundlefile;

import java.io.File;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.AccessController;
import java.util.Enumeration;
import org.eclipse.osgi.container.Module;
import org.eclipse.osgi.framework.util.SecureAction;
import org.eclipse.osgi.storage.url.BundleResourceHandler;
import org.eclipse.osgi.storage.url.bundleresource.Handler;

The BundleFile API is used by Adaptors to read resources out of an 
installed Bundle in the Framework.
 Clients wishing to modify or extend the functionality of this class at runtime should extend the associated decorator instead. /**
 * The BundleFile API is used by Adaptors to read resources out of an 
 * installed Bundle in the Framework.
 * <p/>
 * Clients wishing to modify or extend the functionality of this class at
 * runtime should extend the associated {@link BundleFileWrapper decorator}
 * instead.
 */
abstract public class BundleFile {
	static final SecureAction secureAction = AccessController.doPrivileged(SecureAction.createSecureAction());
	
The File object for this BundleFile.
/**
	 * The File object for this BundleFile.
	 */
	protected File basefile;
	private int mruIndex = -1;

	
BundleFile constructor
Params:
basefile – The File object where this BundleFile is 
persistently stored./**
	 * BundleFile constructor
	 * @param basefile The File object where this BundleFile is 
	 * persistently stored.
	 */
	public BundleFile(File basefile) {
		this.basefile = basefile;
	}

	
Returns a File for the bundle entry specified by the path.
If required the content of the bundle entry is extracted into a file
on the file system.
Params:
path – The path to the entry to locate a File for.
nativeCode – true if the path is native code.
Returns:
A File object to access the contents of the bundle entry./**
	 * Returns a File for the bundle entry specified by the path.
	 * If required the content of the bundle entry is extracted into a file
	 * on the file system.
	 * @param path The path to the entry to locate a File for.
	 * @param nativeCode true if the path is native code.
	 * @return A File object to access the contents of the bundle entry.
	 */
	abstract public File getFile(String path, boolean nativeCode);

	
Locates a file name in this bundle and returns a BundleEntry object
Params:
path – path of the entry to locate in the bundle
Returns:
BundleEntry object or null if the file name
        does not exist in the bundle/**
	 * Locates a file name in this bundle and returns a BundleEntry object
	 *
	 * @param path path of the entry to locate in the bundle
	 * @return BundleEntry object or null if the file name
	 *         does not exist in the bundle
	 */
	abstract public BundleEntry getEntry(String path);

	
Performs the same function as calling getEntryPaths(String, boolean) with recurse equal
to false.
Params:
path – path of the entry to locate in the bundle
Returns:
an Enumeration of Strings that indicate the paths found or
null if the path does not exist./** 
	 * Performs the same function as calling 
	 * {@link #getEntryPaths(String, boolean)} with <code>recurse</code> equal
	 * to <code>false</code>.
	 * @param path path of the entry to locate in the bundle
	 * @return an Enumeration of Strings that indicate the paths found or
	 * null if the path does not exist. 
	 */
	public Enumeration<String> getEntryPaths(String path) {
		return getEntryPaths(path, false);
	}

	
Allows to access the entries of the bundle. 
Since the bundle content is usually a jar, this 
allows to access the jar contents.
GetEntryPaths allows to enumerate the content of "path".
If path is a directory, it is equivalent to listing the directory
contents. The returned names are either files or directories 
themselves. If a returned name is a directory, it finishes with a 
slash. If a returned name is a file, it does not finish with a slash.
Params:
path – path of the entry to locate in the bundle
recurse – - If true, provide entries for the files and 
       directories within the directory denoted by path plus
       all sub-directories and files; otherwise, provide only the entries
       within the immediate directory.
Returns:
an Enumeration of Strings that indicate the paths found or
null if the path does not exist./** 
	 * Allows to access the entries of the bundle. 
	 * Since the bundle content is usually a jar, this 
	 * allows to access the jar contents.
	 * 
	 * GetEntryPaths allows to enumerate the content of "path".
	 * If path is a directory, it is equivalent to listing the directory
	 * contents. The returned names are either files or directories 
	 * themselves. If a returned name is a directory, it finishes with a 
	 * slash. If a returned name is a file, it does not finish with a slash.
	 * @param path path of the entry to locate in the bundle
	 * @param recurse - If <code>true</code>, provide entries for the files and 
	 *        directories within the directory denoted by <code>path</code> plus
	 *        all sub-directories and files; otherwise, provide only the entries
	 *        within the immediate directory.
	 * @return an Enumeration of Strings that indicate the paths found or
	 * null if the path does not exist. 
	 */
	abstract public Enumeration<String> getEntryPaths(String path, boolean recurse);

	
Closes the BundleFile.
Throws:
IOException – if any error occurs./**
	 * Closes the BundleFile.
	 * @throws IOException if any error occurs.
	 */
	abstract public void close() throws IOException;

	
Opens the BundleFiles.
Throws:
IOException – if any error occurs./**
	 * Opens the BundleFiles.
	 * @throws IOException if any error occurs.
	 */
	abstract public void open() throws IOException;

	
Determines if any BundleEntries exist in the given directory path.
Params:
dir – The directory path to check existence of.
Returns:
true if the BundleFile contains entries under the given directory path;
false otherwise./**
	 * Determines if any BundleEntries exist in the given directory path.
	 * @param dir The directory path to check existence of.
	 * @return true if the BundleFile contains entries under the given directory path;
	 * false otherwise.
	 */
	abstract public boolean containsDir(String dir);

	
Returns a URL to access the contents of the entry specified by the path. This method first calls getEntry(String) to locate the entry at the specified path. If no entry is found null is returned; otherwise createResourceURL(BundleEntry, Module, int, String) is called in order to create the URL. Subclasses should not override this method. Instead the methods getEntry(String) and/or createResourceURL(BundleEntry, Module, int, String) may be overriden to augment the behavior. 
Params:
path – the path to the resource
hostModule – the host module
index – the resource index
Returns:
a URL to access the contents of the entry specified by the path/**
	 * Returns a URL to access the contents of the entry specified by the path.
	 * This method first calls {@link #getEntry(String)} to locate the entry
	 * at the specified path.  If no entry is found {@code null} is returned;
	 * otherwise {@link #createResourceURL(BundleEntry, Module, int, String)}
	 * is called in order to create the URL.  Subclasses should not override
	 * this method.  Instead the methods {@link #getEntry(String)} and/or
	 * {@link #createResourceURL(BundleEntry, Module, int, String)} may be
	 * overriden to augment the behavior.
	 * @param path the path to the resource
	 * @param hostModule the host module
	 * @param index the resource index
	 * @return a URL to access the contents of the entry specified by the path
	 */
	public URL getResourceURL(String path, Module hostModule, int index) {
		BundleEntry bundleEntry = getEntry(path);
		if (bundleEntry == null)
			return null;
		return createResourceURL(bundleEntry, hostModule, index, path);
	}

	
Creates a URL to access the content of the specified entry
Params:
bundleEntry – the bundle entry
hostModule – the host module
index – the resource index
path – 
Returns:
a URL to access the contents of the specified entry/**
	 * Creates a URL to access the content of the specified entry
	 * @param bundleEntry the bundle entry
	 * @param hostModule the host module
	 * @param index the resource index
	 * @param path
	 * @return a URL to access the contents of the specified entry
	 */
	protected URL createResourceURL(BundleEntry bundleEntry, Module hostModule, int index, String path) {
		long hostBundleID = hostModule.getId();
		path = fixTrailingSlash(path, bundleEntry);
		try {
			//use the constant string for the protocol to prevent duplication
			return secureAction.getURL(BundleResourceHandler.OSGI_RESOURCE_URL_PROTOCOL, Long.toString(hostBundleID) + BundleResourceHandler.BID_FWKID_SEPARATOR + Integer.toString(hostModule.getContainer().hashCode()), index, path, new Handler(hostModule.getContainer(), bundleEntry));
		} catch (MalformedURLException e) {
			return null;
		}
	}

	
Returns the base file for this BundleFile
Returns:
the base file for this BundleFile/**
	 * Returns the base file for this BundleFile
	 * @return the base file for this BundleFile
	 */
	public File getBaseFile() {
		return basefile;
	}

	void setMruIndex(int index) {
		mruIndex = index;
	}

	int getMruIndex() {
		return mruIndex;
	}

	@Override
	public String toString() {
		return String.valueOf(basefile);
	}

	public static String fixTrailingSlash(String path, BundleEntry entry) {
		if (path.length() == 0)
			return "/"; //$NON-NLS-1$
		if (path.charAt(0) != '/')
			path = '/' + path;
		String name = entry.getName();
		if (name.length() == 0)
			return path;
		boolean pathSlash = path.charAt(path.length() - 1) == '/';
		boolean entrySlash = name.length() > 0 && name.charAt(name.length() - 1) == '/';
		if (entrySlash != pathSlash) {
			if (entrySlash)
				path = path + '/';
			else
				path = path.substring(0, path.length() - 1);
		}
		return path;
	}

}