/*
* Copyright (C) 2014-2015 The Project Lombok Authors.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
package lombok.launch;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Vector;
import java.util.WeakHashMap;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* The shadow classloader serves to completely hide almost all classes in a given jar file by using a different file ending.
*
* The shadow classloader also serves to link in a project as it is being developed (a 'bin' dir from an IDE for example).
* <p>
* Classes loaded by the shadowloader use ".SCL.<em>sclSuffix</em>" in addition to ".class". In other words, most of the class files in a given jar end in this suffix, which
* serves to hide them from any tool that isn't aware of the suffix (such as IDEs generating auto-complete dialogs, and javac's classpath in general). Only shadowloader can actually
* load these classes.
* <p>
* The shadowloader will pick up an alternate (priority) classpath, using normal class files, from the system property "<code>shadow.override.<em>sclSuffix</em></code>".
* This shadow classpath looks just like a normal java classpath; the path separator is applied (semi-colon on windows, colon elsewhere), and entries can consist of directories,
* jar files, or directories ending in "/*" to pick up all jars inside it.
* <p>
* Load order is as follows if at least one override is present:
* <li>First, if the resource is found in one of the paths stated in the shadow classpath, find that.
* <li>Next, ask the <code>parent</code> loader, which is passed during construction of the ShadowClassLoader.
* <li>Notably, this jar's contents are always skipped! (The idea of the shadow classpath is that this jar only functions as a launcher, not as a source of your actual application).
* </ul>
*
* If no overrides are present, the load order is as follows:
* <li>First, if the resource is found in our own jar (trying ".SCL.<em>sclSuffix</em>" first for any resource request ending in ".class"), return that.
* <li>Next, ask the <code>parent</code> loader.
* </ul>
*
* Use ShadowClassLoader to accomplish the following things:<ul>
* <li>Avoid contaminating the namespace of any project using an SCL-based jar. Autocompleters in IDEs will NOT suggest anything other than actual public API.
* <li>Like jarjar, allows folding in dependencies such as ASM without foisting these dependencies on projects that use this jar. shadowloader obviates the need for jarjar.
* <li>Allows an agent (which MUST be in jar form) to still load everything except this loader infrastructure from class files generated by the IDE, which should
* considerably help debugging, as you can now rely on the IDE's built-in auto-recompile features instead of having to run a full build everytime, and it should help
* with hot code replace and the like (this is what the {@code shadow.override} feature is for).
* </ul>
*
* Implementation note: {@code lombok.eclipse.agent.EclipseLoaderPatcher} <em>relies</em> on this class having no dependencies on any other class except the JVM boot class, notably
* including any other classes in this package, <strong>including</strong> inner classes. So, don't write closures, anonymous inner class literals,
* enums, or anything else that could cause the compilation of this file to produce more than 1 class file. In general, actually passing load control to this loader is a bit tricky
* so ensure that this class has zero dependencies on anything except java core classes.
*/
class ShadowClassLoader extends ClassLoader {
private static final String SELF_NAME = "lombok/launch/ShadowClassLoader.class";
private static final ConcurrentMap<String, Class<?>> highlanderMap = new ConcurrentHashMap<String, Class<?>>();
private final String SELF_BASE;
private final File SELF_BASE_FILE;
private final int SELF_BASE_LENGTH;
private final List<File> override = new ArrayList<File>();
private final String sclSuffix;
private final List<String> parentExclusion = new ArrayList<String>();
private final List<String> highlanders = new ArrayList<String>();
/**
* @param source The 'parent' classloader.
* @param sclSuffix The suffix of the shadowed class files in our own jar. For example, if this is {@code lombok}, then the class files in your jar should be {@code foo/Bar.SCL.lombok} and not {@code foo/Bar.class}.
* @param selfBase The (preferably absolute) path to our own jar. This jar will be searched for class/SCL.sclSuffix files.
* @param parentExclusion For example {@code "lombok."}; upon invocation of loadClass of this loader, the parent loader ({@code source}) will NOT be invoked if the class to be loaded begins with anything in the parent exclusion list. No exclusion is applied for getResource(s).
* @param highlanders SCL will put in extra effort to ensure that these classes (in simple class spec, so {@code foo.bar.baz.ClassName}) are only loaded once as a class, even if many different classloaders try to load classes, such as equinox/OSGi.
*/
ShadowClassLoader(ClassLoader source, String sclSuffix, String selfBase, List<String> parentExclusion, List<String> highlanders) {
super(source);
this.sclSuffix = sclSuffix;
if (parentExclusion != null) for (String pe : parentExclusion) {
pe = pe.replace(".", "/");
if (!pe.endsWith("/")) pe = pe + "/";
this.parentExclusion.add(pe);
}
if (highlanders != null) for (String hl : highlanders) {
this.highlanders.add(hl);
}
if (selfBase != null) {
SELF_BASE = selfBase;
SELF_BASE_LENGTH = selfBase.length();
} else {
URL sclClassUrl = ShadowClassLoader.class.getResource("ShadowClassLoader.class");
String sclClassStr = sclClassUrl == null ? null : sclClassUrl.toString();
if (sclClassStr == null || !sclClassStr.endsWith(SELF_NAME)) {
ClassLoader cl = ShadowClassLoader.class.getClassLoader();
throw new RuntimeException("ShadowLoader can't find itself. SCL loader type: " + (cl == null ? "*NULL*" : cl.getClass().toString()));
}
SELF_BASE_LENGTH = sclClassStr.length() - SELF_NAME.length();
String decoded;
try {
decoded = URLDecoder.decode(sclClassStr.substring(0, SELF_BASE_LENGTH), "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new InternalError("UTF-8 not available");
}
SELF_BASE = decoded;
}
if (SELF_BASE.startsWith("jar:file:") && SELF_BASE.endsWith("!/")) SELF_BASE_FILE = new File(SELF_BASE.substring(9, SELF_BASE.length() - 2));
else if (SELF_BASE.startsWith("file:")) SELF_BASE_FILE = new File(SELF_BASE.substring(5));
else SELF_BASE_FILE = new File(SELF_BASE);
String scl = System.getProperty("shadow.override." + sclSuffix);
if (scl != null && !scl.isEmpty()) {
for (String part : scl.split("\\s*" + (File.pathSeparatorChar == ';' ? ";" : ":") + "\\s*")) {
if (part.endsWith("/*") || part.endsWith(File.separator + "*")) {
addOverrideJarDir(part.substring(0, part.length() - 2));
} else {
addOverrideClasspathEntry(part);
}
}
}
}
private final Map<String, Object> mapJarPathToTracker = new HashMap<String, Object>();
private static final Map<Object, String> mapTrackerToJarPath = new WeakHashMap<Object, String>();
private static final Map<Object, Set<String>> mapTrackerToJarContents = new WeakHashMap<Object, Set<String>>();
/**
* This cache ensures that any given jar file is only opened once in order to determine the full contents of it.
* We use 'trackers' to make sure that the bulk of the memory taken up by this cache (the list of strings representing the content of a jar file)
* gets garbage collected if all ShadowClassLoaders that ever tried to request a listing of this jar file, are garbage collected.
*/
private Set<String> getOrMakeJarListing(final String absolutePathToJar) {
synchronized (mapTrackerToJarPath) {
/*
* 1) Check our private instance JarPath-to-Tracker Mappings:
*/
Object ourTracker = mapJarPathToTracker.get(absolutePathToJar);
if (ourTracker != null) {
/*
* Yes, we are already tracking this Jar. Just return its contents...
*/
return mapTrackerToJarContents.get(ourTracker);
}
/*
* 2) Not tracked by us as yet. Check statically whether others have tracked this JarPath:
*/
for (Entry<Object, String> entry : mapTrackerToJarPath.entrySet()) {
if (entry.getValue().equals(absolutePathToJar)) {
/*
* Yes, 3rd party is tracking this jar. We must track too, then return its contents.
*/
Object otherTracker = entry.getKey();
mapJarPathToTracker.put(absolutePathToJar, otherTracker);
return mapTrackerToJarContents.get(otherTracker);
}
}
/*
* 3) Not tracked by anyone so far. Build, publish, track & return Jar contents...
*/
Object newTracker = new Object();
Set<String> jarMembers = getJarMemberSet(absolutePathToJar);
mapTrackerToJarContents.put(newTracker, jarMembers);
mapTrackerToJarPath.put(newTracker, absolutePathToJar);
mapJarPathToTracker.put(absolutePathToJar, newTracker);
return jarMembers;
}
}
/**
* Return a {@link Set} of members in the Jar identified by {@code absolutePathToJar}.
*
* @param absolutePathToJar Cache key
* @return a Set with the Jar member-names
*/
private Set<String> getJarMemberSet(String absolutePathToJar) {
/*
* Note:
* Our implementation returns a HashSet. initialCapacity and loadFactor are carefully tweaked for speed and RAM optimization purposes.
*
* Benchmark:
* The HashSet implementation is about 10% slower to build (only happens once) than the ArrayList.
* The HashSet with shiftBits = 1 was about 33 times(!) faster than the ArrayList for retrievals.
*/
try {
int shiftBits = 1; // (fast, but big) 0 <= shiftBits <= 5, say (slower & compact)
JarFile jar = new JarFile(absolutePathToJar);
/*
* Find the first power of 2 >= JarSize (as calculated in HashSet constructor)
*/
int jarSizePower2 = Integer.highestOneBit(jar.size());
if (jarSizePower2 != jar.size()) jarSizePower2 <<= 1;
if (jarSizePower2 == 0) jarSizePower2 = 1;
Set<String> jarMembers = new HashSet<String>(jarSizePower2 >> shiftBits, 1 << shiftBits);
try {
Enumeration<JarEntry> entries = jar.entries();
while (entries.hasMoreElements()) {
JarEntry jarEntry = entries.nextElement();
if (jarEntry.isDirectory()) continue;
jarMembers.add(jarEntry.getName());
}
} catch (Exception ignore) {
// ignored; if the jar can't be read, treating it as if the jar contains no classes is just what we want.
} finally {
jar.close();
}
return jarMembers;
}
catch (Exception newJarFileException) {
return Collections.emptySet();
}
}
/**
* Looks up {@code altName} in {@code location}, and if that isn't found, looks up {@code name}; {@code altName} can be null in which case it is skipped.
*/
private URL getResourceFromLocation(String name, String altName, File location) {
if (location.isDirectory()) {
try {
if (altName != null) {
File f = new File(location, altName);
if (f.isFile() && f.canRead()) return f.toURI().toURL();
}
File f = new File(location, name);
if (f.isFile() && f.canRead()) return f.toURI().toURL();
return null;
} catch (MalformedURLException e) {
return null;
}
}
if (!location.isFile() || !location.canRead()) return null;
File absoluteFile; {
try {
absoluteFile = location.getCanonicalFile();
} catch (Exception e) {
absoluteFile = location.getAbsoluteFile();
}
}
Set<String> jarContents = getOrMakeJarListing(absoluteFile.getAbsolutePath());
String absoluteUri = absoluteFile.toURI().toString();
try {
if (jarContents.contains(altName)) {
return new URI("jar:" + absoluteUri + "!/" + altName).toURL();
}
} catch (Exception ignore) {
// intentional fallthrough
}
try {
if (jarContents.contains(name)) {
return new URI("jar:" + absoluteUri + "!/" + name).toURL();
}
} catch(Exception ignore) {
// intentional fallthrough
}
return null;
}
/**
* Checks if the stated item is located inside the same classpath root as the jar that hosts ShadowClassLoader.class. {@code item} and {@code name} refer to the same thing.
*/
private boolean inOwnBase(URL item, String name) {
if (item == null) return false;
String itemString = item.toString();
return (itemString.length() == SELF_BASE_LENGTH + name.length()) && SELF_BASE.regionMatches(0, itemString, 0, SELF_BASE_LENGTH);
}
@Override public Enumeration<URL> getResources(String name) throws IOException {
String altName = null;
if (name.endsWith(".class")) altName = name.substring(0, name.length() - 6) + ".SCL." + sclSuffix;
// Vector? Yes, we need one:
// * We can NOT make inner classes here (this class is loaded with special voodoo magic in eclipse, as a one off, it's not a full loader.
// * We need to return an enumeration.
// * We can't make one on the fly.
// * ArrayList can't make these.
Vector<URL> vector = new Vector<URL>();
for (File ce : override) {
URL url = getResourceFromLocation(name, altName, ce);
if (url != null) vector.add(url);
}
if (override.isEmpty()) {
URL fromSelf = getResourceFromLocation(name, altName, SELF_BASE_FILE);
if (fromSelf != null) vector.add(fromSelf);
}
Enumeration<URL> sec = super.getResources(name);
while (sec.hasMoreElements()) {
URL item = sec.nextElement();
if (!inOwnBase(item, name)) vector.add(item);
}
if (altName != null) {
Enumeration<URL> tern = super.getResources(altName);
while (tern.hasMoreElements()) {
URL item = tern.nextElement();
if (!inOwnBase(item, altName)) vector.add(item);
}
}
return vector.elements();
}
@Override public URL getResource(String name) {
return getResource_(name, false);
}
private URL getResource_(String name, boolean noSuper) {
String altName = null;
if (name.endsWith(".class")) altName = name.substring(0, name.length() - 6) + ".SCL." + sclSuffix;
for (File ce : override) {
URL url = getResourceFromLocation(name, altName, ce);
if (url != null) return url;
}
if (!override.isEmpty()) {
if (noSuper) return null;
if (altName != null) {
try {
URL res = getResourceSkippingSelf(altName);
if (res != null) return res;
} catch (IOException ignore) {}
}
try {
return getResourceSkippingSelf(name);
} catch (IOException e) {
return null;
}
}
URL url = getResourceFromLocation(name, altName, SELF_BASE_FILE);
if (url != null) return url;
if (altName != null) {
URL res = super.getResource(altName);
if (res != null && (!noSuper || inOwnBase(res, altName))) return res;
}
URL res = super.getResource(name);
if (res != null && (!noSuper || inOwnBase(res, name))) return res;
return null;
}
private boolean exclusionListMatch(String name) {
for (String pe : parentExclusion) {
if (name.startsWith(pe)) return true;
}
return false;
}
private URL getResourceSkippingSelf(String name) throws IOException {
URL candidate = super.getResource(name);
if (candidate == null) return null;
if (!inOwnBase(candidate, name)) return candidate;
Enumeration<URL> en = super.getResources(name);
while (en.hasMoreElements()) {
candidate = en.nextElement();
if (!inOwnBase(candidate, name)) return candidate;
}
return null;
}
@Override public Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException {
{
Class<?> alreadyLoaded = findLoadedClass(name);
if (alreadyLoaded != null) return alreadyLoaded;
}
if (highlanders.contains(name)) {
Class<?> c = highlanderMap.get(name);
if (c != null) return c;
}
String fileNameOfClass = name.replace(".", "/") + ".class";
URL res = getResource_(fileNameOfClass, true);
if (res == null) {
if (!exclusionListMatch(fileNameOfClass)) return super.loadClass(name, resolve);
throw new ClassNotFoundException(name);
}
byte[] b;
int p = 0;
try {
InputStream in = res.openStream();
try {
b = new byte[65536];
while (true) {
int r = in.read(b, p, b.length - p);
if (r == -1) break;
p += r;
if (p == b.length) {
byte[] nb = new byte[b.length * 2];
System.arraycopy(b, 0, nb, 0, p);
b = nb;
}
}
} finally {
in.close();
}
} catch (IOException e) {
throw new ClassNotFoundException("I/O exception reading class " + name, e);
}
Class<?> c;
try {
c = defineClass(name, b, 0, p);
} catch (LinkageError e) {
if (highlanders.contains(name)) {
Class<?> alreadyDefined = highlanderMap.get(name);
if (alreadyDefined != null) return alreadyDefined;
}
try {
c = this.findLoadedClass(name);
} catch (LinkageError e2) {
throw e;
}
if (c == null) throw e;
}
if (highlanders.contains(name)) {
Class<?> alreadyDefined = highlanderMap.putIfAbsent(name, c);
if (alreadyDefined != null) c = alreadyDefined;
}
if (resolve) resolveClass(c);
return c;
}
public void addOverrideJarDir(String dir) {
File f = new File(dir);
for (File j : f.listFiles()) {
if (j.getName().toLowerCase().endsWith(".jar") && j.canRead() && j.isFile()) override.add(j);
}
}
public void addOverrideClasspathEntry(String entry) {
override.add(new File(entry));
}
}