Java tutorial
/* * Copyright (c) 1997, 2019, 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 * questions. */ package java.util.jar; import java.io.DataOutputStream; import java.io.FilterInputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.util.HashMap; import java.util.Map; import sun.security.util.SecurityProperties; import static java.nio.charset.StandardCharsets.UTF_8; /** * The Manifest class is used to maintain Manifest entry names and their * associated Attributes. There are main Manifest Attributes as well as * per-entry Attributes. For information on the Manifest format, please * see the * <a href="{@docRoot}/../specs/jar/jar.html"> * Manifest format specification</a>. * * @author David Connelly * @see Attributes * @since 1.2 */ public class Manifest implements Cloneable { // manifest main attributes private final Attributes attr = new Attributes(); // manifest entries private final Map<String, Attributes> entries = new HashMap<>(); // associated JarVerifier, not null when called by JarFile::getManifest. private final JarVerifier jv; /** * Constructs a new, empty Manifest. */ public Manifest() { jv = null; } /** * Constructs a new Manifest from the specified input stream. * * @param is the input stream containing manifest data * @throws IOException if an I/O error has occurred */ public Manifest(InputStream is) throws IOException { this(null, is, null); } /** * Constructs a new Manifest from the specified input stream. * * @param is the input stream containing manifest data * @param jarFilename the name of the corresponding jar archive if available * @throws IOException if an I/O error has occurred */ Manifest(InputStream is, String jarFilename) throws IOException { this(null, is, jarFilename); } /** * Constructs a new Manifest from the specified input stream * and associates it with a JarVerifier. * * @param jv the JarVerifier to use * @param is the input stream containing manifest data * @param jarFilename the name of the corresponding jar archive if available * @throws IOException if an I/O error has occurred */ Manifest(JarVerifier jv, InputStream is, String jarFilename) throws IOException { read(is, jarFilename); this.jv = jv; } /** * Constructs a new Manifest that is a copy of the specified Manifest. * * @param man the Manifest to copy */ public Manifest(Manifest man) { attr.putAll(man.getMainAttributes()); entries.putAll(man.getEntries()); jv = man.jv; } /** * Returns the main Attributes for the Manifest. * @return the main Attributes for the Manifest */ public Attributes getMainAttributes() { return attr; } /** * Returns a Map of the entries contained in this Manifest. Each entry * is represented by a String name (key) and associated Attributes (value). * The Map permits the {@code null} key, but no entry with a null key is * created by {@link #read}, nor is such an entry written by using {@link * #write}. * * @return a Map of the entries contained in this Manifest */ public Map<String, Attributes> getEntries() { return entries; } /** * Returns the Attributes for the specified entry name. * This method is defined as: * <pre> * return (Attributes)getEntries().get(name) * </pre> * Though {@code null} is a valid {@code name}, when * {@code getAttributes(null)} is invoked on a {@code Manifest} * obtained from a jar file, {@code null} will be returned. While jar * files themselves do not allow {@code null}-named attributes, it is * possible to invoke {@link #getEntries} on a {@code Manifest}, and * on that result, invoke {@code put} with a null key and an * arbitrary value. Subsequent invocations of * {@code getAttributes(null)} will return the just-{@code put} * value. * <p> * Note that this method does not return the manifest's main attributes; * see {@link #getMainAttributes}. * * @param name entry name * @return the Attributes for the specified entry name */ public Attributes getAttributes(String name) { return getEntries().get(name); } /** * Returns the Attributes for the specified entry name, if trusted. * * @param name entry name * @return returns the same result as {@link #getAttributes(String)} * @throws SecurityException if the associated jar is signed but this entry * has been modified after signing (i.e. the section in the manifest * does not exist in SF files of all signers). */ Attributes getTrustedAttributes(String name) { // Note: Before the verification of MANIFEST.MF/.SF/.RSA files is done, // jv.isTrustedManifestEntry() isn't able to detect MANIFEST.MF change. // Users of this method should call SharedSecrets.javaUtilJarAccess() // .ensureInitialization() first. Attributes result = getAttributes(name); if (result != null && jv != null && !jv.isTrustedManifestEntry(name)) { throw new SecurityException("Untrusted manifest entry: " + name); } return result; } /** * Clears the main Attributes as well as the entries in this Manifest. */ public void clear() { attr.clear(); entries.clear(); } /** * Writes the Manifest to the specified OutputStream. * Attributes.Name.MANIFEST_VERSION must be set in * MainAttributes prior to invoking this method. * * @param out the output stream * @exception IOException if an I/O error has occurred * @see #getMainAttributes */ public void write(OutputStream out) throws IOException { DataOutputStream dos = new DataOutputStream(out); // Write out the main attributes for the manifest attr.writeMain(dos); // Now write out the per-entry attributes StringBuilder buffer = entries.isEmpty() ? null : new StringBuilder(72); for (Map.Entry<String, Attributes> e : entries.entrySet()) { buffer.setLength(0); buffer.append("Name: "); buffer.append(e.getKey()); println72(dos, buffer.toString()); e.getValue().write(dos); } dos.flush(); } /** * Adds line breaks to enforce a maximum of 72 bytes per line. * * @deprecation Replaced with {@link #println72}. */ @Deprecated(since = "13") static void make72Safe(StringBuffer line) { int length = line.length(); int index = 72; while (index < length) { line.insert(index, "\r\n "); index += 74; // + line width + line break ("\r\n") length += 3; // + line break ("\r\n") and space } } /** * Writes {@code line} to {@code out} with line breaks and continuation * spaces within the limits of 72 bytes of contents per line followed * by a line break. */ static void println72(OutputStream out, String line) throws IOException { if (!line.isEmpty()) { byte[] lineBytes = line.getBytes(UTF_8); int length = lineBytes.length; // first line can hold one byte more than subsequent lines which // start with a continuation line break space out.write(lineBytes[0]); int pos = 1; while (length - pos > 71) { out.write(lineBytes, pos, 71); pos += 71; println(out); out.write(' '); } out.write(lineBytes, pos, length - pos); } println(out); } /** * Writes a line break to {@code out}. */ static void println(OutputStream out) throws IOException { out.write('\r'); out.write('\n'); } static String getErrorPosition(String filename, final int lineNumber) { if (filename == null || !SecurityProperties.INCLUDE_JAR_NAME_IN_EXCEPTIONS) { return "line " + lineNumber; } return "manifest of " + filename + ":" + lineNumber; } /** * Reads the Manifest from the specified InputStream. The entry * names and attributes read will be merged in with the current * manifest entries. * * @param is the input stream * @exception IOException if an I/O error has occurred */ public void read(InputStream is) throws IOException { read(is, null); } private void read(InputStream is, String jarFilename) throws IOException { // Buffered input stream for reading manifest data FastInputStream fis = new FastInputStream(is); // Line buffer byte[] lbuf = new byte[512]; // Read the main attributes for the manifest int lineNumber = attr.read(fis, lbuf, jarFilename, 0); // Total number of entries, attributes read int ecount = 0, acount = 0; // Average size of entry attributes int asize = 2; // Now parse the manifest entries int len; String name = null; boolean skipEmptyLines = true; byte[] lastline = null; while ((len = fis.readLine(lbuf)) != -1) { byte c = lbuf[--len]; lineNumber++; if (c != '\n' && c != '\r') { throw new IOException("manifest line too long (" + getErrorPosition(jarFilename, lineNumber) + ")"); } if (len > 0 && lbuf[len - 1] == '\r') { --len; } if (len == 0 && skipEmptyLines) { continue; } skipEmptyLines = false; if (name == null) { name = parseName(lbuf, len); if (name == null) { throw new IOException( "invalid manifest format (" + getErrorPosition(jarFilename, lineNumber) + ")"); } if (fis.peek() == ' ') { // name is wrapped lastline = new byte[len - 6]; System.arraycopy(lbuf, 6, lastline, 0, len - 6); continue; } } else { // continuation line byte[] buf = new byte[lastline.length + len - 1]; System.arraycopy(lastline, 0, buf, 0, lastline.length); System.arraycopy(lbuf, 1, buf, lastline.length, len - 1); if (fis.peek() == ' ') { // name is wrapped lastline = buf; continue; } name = new String(buf, 0, buf.length, UTF_8); lastline = null; } Attributes attr = getAttributes(name); if (attr == null) { attr = new Attributes(asize); entries.put(name, attr); } lineNumber = attr.read(fis, lbuf, jarFilename, lineNumber); ecount++; acount += attr.size(); //XXX: Fix for when the average is 0. When it is 0, // you get an Attributes object with an initial // capacity of 0, which tickles a bug in HashMap. asize = Math.max(2, acount / ecount); name = null; skipEmptyLines = true; } } private String parseName(byte[] lbuf, int len) { if (toLower(lbuf[0]) == 'n' && toLower(lbuf[1]) == 'a' && toLower(lbuf[2]) == 'm' && toLower(lbuf[3]) == 'e' && lbuf[4] == ':' && lbuf[5] == ' ') { try { return new String(lbuf, 6, len - 6, UTF_8); } catch (Exception e) { } } return null; } private int toLower(int c) { return (c >= 'A' && c <= 'Z') ? 'a' + (c - 'A') : c; } /** * Returns true if the specified Object is also a Manifest and has * the same main Attributes and entries. * * @param o the object to be compared * @return true if the specified Object is also a Manifest and has * the same main Attributes and entries */ public boolean equals(Object o) { if (o instanceof Manifest) { Manifest m = (Manifest) o; return attr.equals(m.getMainAttributes()) && entries.equals(m.getEntries()); } else { return false; } } /** * Returns the hash code for this Manifest. */ public int hashCode() { return attr.hashCode() + entries.hashCode(); } /** * Returns a shallow copy of this Manifest. The shallow copy is * implemented as follows: * <pre> * public Object clone() { return new Manifest(this); } * </pre> * @return a shallow copy of this Manifest */ public Object clone() { return new Manifest(this); } /* * A fast buffered input stream for parsing manifest files. */ static class FastInputStream extends FilterInputStream { private byte buf[]; private int count = 0; private int pos = 0; FastInputStream(InputStream in) { this(in, 8192); } FastInputStream(InputStream in, int size) { super(in); buf = new byte[size]; } public int read() throws IOException { if (pos >= count) { fill(); if (pos >= count) { return -1; } } return Byte.toUnsignedInt(buf[pos++]); } public int read(byte[] b, int off, int len) throws IOException { int avail = count - pos; if (avail <= 0) { if (len >= buf.length) { return in.read(b, off, len); } fill(); avail = count - pos; if (avail <= 0) { return -1; } } if (len > avail) { len = avail; } System.arraycopy(buf, pos, b, off, len); pos += len; return len; } /* * Reads 'len' bytes from the input stream, or until an end-of-line * is reached. Returns the number of bytes read. */ public int readLine(byte[] b, int off, int len) throws IOException { byte[] tbuf = this.buf; int total = 0; while (total < len) { int avail = count - pos; if (avail <= 0) { fill(); avail = count - pos; if (avail <= 0) { return -1; } } int n = len - total; if (n > avail) { n = avail; } int tpos = pos; int maxpos = tpos + n; byte c = 0; // jar.spec.newline: CRLF | LF | CR (not followed by LF) while (tpos < maxpos && (c = tbuf[tpos++]) != '\n' && c != '\r') ; if (c == '\r' && tpos < maxpos && tbuf[tpos] == '\n') { tpos++; } n = tpos - pos; System.arraycopy(tbuf, pos, b, off, n); off += n; total += n; pos = tpos; c = tbuf[tpos - 1]; if (c == '\n') { break; } if (c == '\r') { if (count == pos) { // try to see if there is a trailing LF fill(); if (pos < count && tbuf[pos] == '\n') { if (total < len) { b[off++] = '\n'; total++; } else { // we should always have big enough lbuf but // just in case we don't, replace the last CR // with LF. b[off - 1] = '\n'; } pos++; } } break; } } return total; } public byte peek() throws IOException { if (pos == count) fill(); if (pos == count) return -1; // nothing left in buffer return buf[pos]; } public int readLine(byte[] b) throws IOException { return readLine(b, 0, b.length); } public long skip(long n) throws IOException { if (n <= 0) { return 0; } long avail = count - pos; if (avail <= 0) { return in.skip(n); } if (n > avail) { n = avail; } pos += n; return n; } public int available() throws IOException { return (count - pos) + in.available(); } public void close() throws IOException { if (in != null) { in.close(); in = null; buf = null; } } private void fill() throws IOException { count = pos = 0; int n = in.read(buf, 0, buf.length); if (n > 0) { count = n; } } } }