/*
* Copyright (c) 2014, 2016, 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
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*/
package java.lang.module;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UncheckedIOException;
import java.lang.module.ModuleDescriptor.Requires;
import java.nio.file.DirectoryStream;
import java.nio.file.Files;
import java.nio.file.NoSuchFileException;
import java.nio.file.Path;
import java.nio.file.attribute.BasicFileAttributes;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.jar.Attributes;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
import java.util.jar.Manifest;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import jdk.internal.module.Checks;
import jdk.internal.module.ConfigurableModuleFinder;
import jdk.internal.perf.PerfCounter;
/**
* A {@code ModuleFinder} that locates modules on the file system by searching
* a sequence of directories or packaged modules.
*
* The {@code ModuleFinder} can be configured to work in either the run-time
* or link-time phases. In both cases it locates modular JAR and exploded
* modules. When configured for link-time then it additionally locates
* modules in JMOD files.
*/
class ModulePath implements ConfigurableModuleFinder {
private static final String MODULE_INFO = "module-info.class";
// the entries on this module path
private final Path[] entries;
private int next;
// true if in the link phase
private boolean isLinkPhase;
// map of module name to module reference map for modules already located
private final Map<String, ModuleReference> cachedModules = new HashMap<>();
ModulePath(Path... entries) {
this.entries = entries.clone();
for (Path entry : this.entries) {
Objects.requireNonNull(entry);
}
}
@Override
public void configurePhase(Phase phase) {
isLinkPhase = (phase == Phase.LINK_TIME);
}
@Override
public Optional<ModuleReference> find(String name) {
Objects.requireNonNull(name);
// try cached modules
ModuleReference m = cachedModules.get(name);
if (m != null)
return Optional.of(m);
// the module may not have been encountered yet
while (hasNextEntry()) {
scanNextEntry();
m = cachedModules.get(name);
if (m != null)
return Optional.of(m);
}
return Optional.empty();
}
@Override
public Set<ModuleReference> findAll() {
// need to ensure that all entries have been scanned
while (hasNextEntry()) {
scanNextEntry();
}
return cachedModules.values().stream().collect(Collectors.toSet());
}
/**
* Returns {@code true} if there are additional entries to scan
*/
private boolean hasNextEntry() {
return next < entries.length;
}
/**
* Scans the next entry on the module path. A no-op if all entries have
* already been scanned.
*
* @throws FindException if an error occurs scanning the next entry
*/
private void scanNextEntry() {
if (hasNextEntry()) {
long t0 = System.nanoTime();
Path entry = entries[next];
Map<String, ModuleReference> modules = scan(entry);
next++;
// update cache, ignoring duplicates
int initialSize = cachedModules.size();
for (Map.Entry<String, ModuleReference> e : modules.entrySet()) {
cachedModules.putIfAbsent(e.getKey(), e.getValue());
}
// update counters
int added = cachedModules.size() - initialSize;
moduleCount.add(added);
scanTime.addElapsedTimeFrom(t0);
}
}
/**
* Scan the given module path entry. If the entry is a directory then it is
* a directory of modules or an exploded module. If the entry is a regular
* file then it is assumed to be a packaged module.
*
* @throws FindException if an error occurs scanning the entry
*/
private Map<String, ModuleReference> scan(Path entry) {
BasicFileAttributes attrs;
try {
attrs = Files.readAttributes(entry, BasicFileAttributes.class);
} catch (NoSuchFileException e) {
return Collections.emptyMap();
} catch (IOException ioe) {
throw new FindException(ioe);
}
try {
if (attrs.isDirectory()) {
Path mi = entry.resolve(MODULE_INFO);
if (!Files.exists(mi)) {
// does not exist or unable to determine so assume a
// directory of modules
return scanDirectory(entry);
}
}
if (attrs.isRegularFile() || attrs.isDirectory()) {
// packaged or exploded module
ModuleReference mref = readModule(entry, attrs);
if (mref != null) {
String name = mref.descriptor().name();
return Collections.singletonMap(name, mref);
}
}
// not recognized
throw new FindException("Unrecognized module: " + entry);
} catch (IOException ioe) {
throw new FindException(ioe);
}
}
/**
* Scans the given directory for packaged or exploded modules.
*
* @return a map of module name to ModuleReference for the modules found
* in the directory
*
* @throws IOException if an I/O error occurs
* @throws FindException if an error occurs scanning the entry or the
* directory contains two or more modules with the same name
*/
private Map<String, ModuleReference> scanDirectory(Path dir)
throws IOException
{
// The map of name -> mref of modules found in this directory.
Map<String, ModuleReference> nameToReference = new HashMap<>();
try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
for (Path entry : stream) {
BasicFileAttributes attrs;
try {
attrs = Files.readAttributes(entry, BasicFileAttributes.class);
} catch (NoSuchFileException ignore) {
// file has been removed or moved, ignore for now
continue;
}
ModuleReference mref = readModule(entry, attrs);
// module found
if (mref != null) {
// can have at most one version of a module in the directory
String name = mref.descriptor().name();
if (nameToReference.put(name, mref) != null) {
throw new FindException("Two versions of module "
+ name + " found in " + dir);
}
}
}
}
return nameToReference;
}
/**
* Locates a packaged or exploded module, returning a {@code ModuleReference}
* to the module. Returns {@code null} if the module is not recognized
* as a packaged or exploded module.
*
* @throws IOException if an I/O error occurs
* @throws FindException if an error occurs parsing the module descriptor
*/
private ModuleReference readModule(Path entry, BasicFileAttributes attrs)
throws IOException
{
try {
ModuleReference mref = null;
if (attrs.isDirectory()) {
mref = readExplodedModule(entry);
} if (attrs.isRegularFile()) {
if (entry.toString().endsWith(".jar")) {
mref = readJar(entry);
} else if (isLinkPhase && entry.toString().endsWith(".jmod")) {
mref = readJMod(entry);
}
}
return mref;
} catch (InvalidModuleDescriptorException e) {
throw new FindException("Error reading module: " + entry, e);
}
}
// -- jmod files --
private Set<String> jmodPackages(ZipFile zf) {
return zf.stream()
.filter(e -> e.getName().startsWith("classes/") &&
e.getName().endsWith(".class"))
.map(e -> toPackageName(e))
.filter(pkg -> pkg.length() > 0) // module-info
.distinct()
.collect(Collectors.toSet());
}
/**
* Returns a {@code ModuleReference} to a module in jmod file on the
* file system.
*/
private ModuleReference readJMod(Path file) throws IOException {
try (ZipFile zf = new ZipFile(file.toString())) {
ZipEntry ze = zf.getEntry("classes/" + MODULE_INFO);
if (ze == null) {
throw new IOException(MODULE_INFO + " is missing: " + file);
}
ModuleDescriptor md;
try (InputStream in = zf.getInputStream(ze)) {
md = ModuleDescriptor.read(in, () -> jmodPackages(zf));
}
return ModuleReferences.newJModModule(md, file);
}
}
// -- JAR files --
private static final String SERVICES_PREFIX = "META-INF/services/";
/**
* Returns a container with the service type corresponding to the name of
* a services configuration file.
*
* For example, if called with "META-INF/services/p.S" then this method
* returns a container with the value "p.S".
*/
private Optional<String> toServiceName(String cf) {
assert cf.startsWith(SERVICES_PREFIX);
int index = cf.lastIndexOf("/") + 1;
if (index < cf.length()) {
String prefix = cf.substring(0, index);
if (prefix.equals(SERVICES_PREFIX)) {
String sn = cf.substring(index);
if (Checks.isJavaIdentifier(sn))
return Optional.of(sn);
}
}
return Optional.empty();
}
/**
* Reads the next line from the given reader and trims it of comments and
* leading/trailing white space.
*
* Returns null if the reader is at EOF.
*/
private String nextLine(BufferedReader reader) throws IOException {
String ln = reader.readLine();
if (ln != null) {
int ci = ln.indexOf('#');
if (ci >= 0)
ln = ln.substring(0, ci);
ln = ln.trim();
}
return ln;
}
/**
* Treat the given JAR file as a module as follows:
*
* 1. The module name (and optionally the version) is derived from the file
* name of the JAR file
* 2. The packages of all .class files in the JAR file are exported
* 3. It has no module-private/concealed packages
* 4. The contents of any META-INF/services configuration files are mapped
* to "provides" declarations
* 5. The Main-Class attribute in the main attributes of the JAR manifest
* is mapped to the module descriptor mainClass
*
* @apiNote This needs to move to somewhere where it can be used by tools,
* maybe even a standard API if automatic modules are a Java SE feature.
*/
private ModuleDescriptor deriveModuleDescriptor(JarFile jf)
throws IOException
{
// Derive module name and version from JAR file name
String fn = jf.getName();
int i = fn.lastIndexOf(File.separator);
if (i != -1)
fn = fn.substring(i+1);
// drop .jar
String mn = fn.substring(0, fn.length()-4);
String vs = null;
// find first occurrence of -${NUMBER}. or -${NUMBER}$
Matcher matcher = Pattern.compile("-(\\d+(\\.|$))").matcher(mn);
if (matcher.find()) {
int start = matcher.start();
// attempt to parse the tail as a version string
try {
String tail = mn.substring(start+1);
ModuleDescriptor.Version.parse(tail);
vs = tail;
} catch (IllegalArgumentException ignore) { }
mn = mn.substring(0, start);
}
// finally clean up the module name
mn = mn.replaceAll("[^A-Za-z0-9]", ".") // replace non-alphanumeric
.replaceAll("(\\.)(\\1)+", ".") // collapse repeating dots
.replaceAll("^\\.", "") // drop leading dots
.replaceAll("\\.$", ""); // drop trailing dots
// Builder throws IAE if module name is empty or invalid
ModuleDescriptor.Builder builder
= new ModuleDescriptor.Builder(mn, true)
.requires(Requires.Modifier.MANDATED, "java.base");
if (vs != null)
builder.version(vs);
// scan the entries in the JAR file to locate the .class and service
// configuration file
Stream<String> stream = jf.stream()
.map(e -> e.getName())
.filter(e -> (e.endsWith(".class") || e.startsWith(SERVICES_PREFIX)))
.distinct();
Map<Boolean, Set<String>> map
= stream.collect(Collectors.partitioningBy(s -> s.endsWith(".class"),
Collectors.toSet()));
Set<String> classFiles = map.get(Boolean.TRUE);
Set<String> configFiles = map.get(Boolean.FALSE);
// all packages are exported
classFiles.stream()
.map(c -> toPackageName(c))
.distinct()
.forEach(p -> builder.exports(p));
// map names of service configuration files to service names
Set<String> serviceNames = configFiles.stream()
.map(this::toServiceName)
.filter(Optional::isPresent)
.map(Optional::get)
.collect(Collectors.toSet());
// parse each service configuration file
for (String sn : serviceNames) {
JarEntry entry = jf.getJarEntry(SERVICES_PREFIX + sn);
Set<String> providerClasses = new HashSet<>();
try (InputStream in = jf.getInputStream(entry)) {
BufferedReader reader
= new BufferedReader(new InputStreamReader(in, "UTF-8"));
String cn;
while ((cn = nextLine(reader)) != null) {
if (Checks.isJavaIdentifier(cn)) {
providerClasses.add(cn);
}
}
}
if (!providerClasses.isEmpty())
builder.provides(sn, providerClasses);
}
// Main-Class attribute if it exists
Manifest man = jf.getManifest();
if (man != null) {
Attributes attrs = man.getMainAttributes();
String mainClass = attrs.getValue(Attributes.Name.MAIN_CLASS);
if (mainClass != null)
builder.mainClass(mainClass);
}
return builder.build();
}
private Set<String> jarPackages(JarFile jf) {
return jf.stream()
.filter(e -> e.getName().endsWith(".class"))
.map(e -> toPackageName(e))
.filter(pkg -> pkg.length() > 0) // module-info
.distinct()
.collect(Collectors.toSet());
}
/**
* Returns a {@code ModuleReference} to a module in modular JAR file on
* the file system.
*/
private ModuleReference readJar(Path file) throws IOException {
try (JarFile jf = new JarFile(file.toString())) {
ModuleDescriptor md;
JarEntry entry = jf.getJarEntry(MODULE_INFO);
if (entry == null) {
// no module-info.class so treat it as automatic module
try {
md = deriveModuleDescriptor(jf);
} catch (IllegalArgumentException iae) {
throw new FindException(
"Unable to derive module descriptor for: "
+ jf.getName(), iae);
}
} else {
md = ModuleDescriptor.read(jf.getInputStream(entry),
() -> jarPackages(jf));
}
return ModuleReferences.newJarModule(md, file);
}
}
// -- exploded directories --
private Set<String> explodedPackages(Path dir) {
try {
return Files.find(dir, Integer.MAX_VALUE,
((path, attrs) -> attrs.isRegularFile() &&
path.toString().endsWith(".class")))
.map(path -> toPackageName(dir.relativize(path)))
.filter(pkg -> pkg.length() > 0) // module-info
.distinct()
.collect(Collectors.toSet());
} catch (IOException x) {
throw new UncheckedIOException(x);
}
}
/**
* Returns a {@code ModuleReference} to an exploded module on the file
* system or {@code null} if {@code module-info.class} not found.
*/
private ModuleReference readExplodedModule(Path dir) throws IOException {
Path mi = dir.resolve(MODULE_INFO);
ModuleDescriptor md;
try (InputStream in = Files.newInputStream(mi)) {
md = ModuleDescriptor.read(new BufferedInputStream(in),
() -> explodedPackages(dir));
} catch (NoSuchFileException e) {
// for now
return null;
}
return ModuleReferences.newExplodedModule(md, dir);
}
//
// p/q/T.class => p.q
private String toPackageName(String cn) {
assert cn.endsWith(".class");
int start = 0;
int index = cn.lastIndexOf("/");
if (index > start) {
return cn.substring(start, index).replace('/', '.');
} else {
return "";
}
}
private String toPackageName(ZipEntry entry) {
String name = entry.getName();
assert name.endsWith(".class");
// jmod classes in classes/, jar in /
int start = name.startsWith("classes/") ? 8 : 0;
int index = name.lastIndexOf("/");
if (index > start) {
return name.substring(start, index).replace('/', '.');
} else {
return "";
}
}
private String toPackageName(Path path) {
String name = path.toString();
assert name.endsWith(".class");
int index = name.lastIndexOf(File.separatorChar);
if (index != -1) {
return name.substring(0, index).replace(File.separatorChar, '.');
} else {
return "";
}
}
private static final PerfCounter scanTime
= PerfCounter.newPerfCounter("jdk.module.finder.modulepath.scanTime");
private static final PerfCounter moduleCount
= PerfCounter.newPerfCounter("jdk.module.finder.modulepath.modules");
}