jarfile.java

JAVA基本类源代码,大家可以学习学习!

		}
	    }
	    return certs;
	}
    }
	    
    /*
     * Ensures that the JarVerifier has been created if one is
     * necessary (i.e., the jar appears to be signed.) This is done as
     * a quick check to avoid processing of the manifest for unsigned
     * jars.
     */
    private void maybeInstantiateVerifier() throws IOException {
        if (jv != null) {
            return;
        }

        if (verify) {
            String[] names = getMetaInfEntryNames();
            if (names != null) {
                for (int i = 0; i < names.length; i++) {
                    String name = names[i].toUpperCase(Locale.ENGLISH);
                    if (name.endsWith(".DSA") ||
                        name.endsWith(".RSA") ||
                        name.endsWith(".SF")) {
                        // Assume since we found a signature-related file
                        // that the jar is signed and that we therefore
                        // need a JarVerifier and Manifest
                        getManifest();
                        return;
                    }
                }
            }
            // No signature-related files; don't instantiate a
            // verifier
            verify = false;
        }
    }


    /*
     * Initializes the verifier object by reading all the manifest
     * entries and passing them to the verifier.
     */
    private void initializeVerifier() {
	ManifestEntryVerifier mev = null;

	// Verify "META-INF/" entries...
	try {
	    String[] names = getMetaInfEntryNames();
	    if (names != null) {
		for (int i = 0; i < names.length; i++) {
		    JarEntry e = getJarEntry(names[i]);
		    if (!e.isDirectory()) {
			if (mev == null) {
			    mev = new ManifestEntryVerifier(man);
			}
			byte[] b = getBytes(e);
			if (b != null && b.length > 0) {
			    jv.beginEntry(e, mev);
			    jv.update(b.length, b, 0, b.length, mev);
			    jv.update(-1, null, 0, 0, mev);
			}
		    }
		}
	    }
	} catch (IOException ex) {
	    // if we had an error parsing any blocks, just
	    // treat the jar file as being unsigned
	    jv = null;
            verify = false;
	}

	// if after initializing the verifier we have nothing
	// signed, we null it out.

	if (jv != null) {

	    jv.doneWithMeta();
	    if (JarVerifier.debug != null) {
		JarVerifier.debug.println("done with meta!"); 
	    }

	    if (jv.nothingToVerify()) {
		if (JarVerifier.debug != null) {
		    JarVerifier.debug.println("nothing to verify!");
		}
		jv = null;
                verify = false;
	    }
	}
    }

    /*
     * Reads all the bytes for a given entry. Used to process the
     * the META-INF files.
     */
    private byte[] getBytes(ZipEntry ze) throws IOException {
	byte[] b = new byte[(int)ze.getSize()];
	DataInputStream is = new DataInputStream(super.getInputStream(ze));
	is.readFully(b, 0, b.length);
	is.close();
	return b;
    }

    /**
     * Returns an input stream for reading the contents of the specified
     * ZIP file entry.
     * @param ze the zip file entry
     * @return an input stream for reading the contents of the specified
     *         ZIP file entry
     * @exception ZipException if a ZIP format error has occurred
     * @exception IOException if an I/O error has occurred
     * @exception SecurityException if any of the JarFile entries are incorrectly signed.
     */
    public synchronized InputStream getInputStream(ZipEntry ze) 
	throws IOException 
    {
        maybeInstantiateVerifier();
	if (jv == null) {
	    return super.getInputStream(ze);
	}
	if (!jvInitialized) {
	    initializeVerifier();
	    jvInitialized = true;
	    // could be set to null after a call to
	    // initializeVerifier if we have nothing to
	    // verify
	    if (jv == null)
		return super.getInputStream(ze);
	}

	// wrap a verifier stream around the real stream
	return new JarVerifier.VerifierStream(man, (JarEntry)ze,
					      super.getInputStream(ze), jv);
    }

    // Statics for hand-coded Boyer-Moore search in hasClassPathAttribute()
    // The bad character shift for "class-path"
    private static int[] lastOcc;
    // The good suffix shift for "class-path"
    private static int[] optoSft;
    // Initialize the shift arrays to search for "class-path"
    private static char[] src = {'c','l','a','s','s','-','p','a','t','h'};
    static {
        lastOcc = new int[128];
        optoSft = new int[10];
        lastOcc[99]=1; lastOcc[108]=2; lastOcc[97]=8; lastOcc[115]=5;
        lastOcc[116]=9; lastOcc[45]=6; lastOcc[112]=7; lastOcc[104]=10;
        for (int i=0; i<9; i++)
            optoSft[i]=10;
        optoSft[9]=1;
    }
 
    // Returns true iff this jar file has a manifest with a class path
    // attribute. Returns false if there is no manifest or the manifest
    // does not contain a "Class-Path" attribute. Currently exported to
    // core libraries via sun.misc.SharedSecrets.
    boolean hasClassPathAttribute() throws IOException {
        if (computedHasClassPathAttribute) {
            return hasClassPathAttribute;
        }

        hasClassPathAttribute = false;
        if (!isKnownToNotHaveClassPathAttribute()) {
            JarEntry manEntry = getJarEntry(MANIFEST_NAME);
            if (manEntry == null) {
                // If not found, then iterate through all the "META-INF/"
                // entries to find a match.
                String[] names = getMetaInfEntryNames();
                if (names != null) {
                    for (int i = 0; i < names.length; i++) {
                        if (MANIFEST_NAME.equals(
                                                 names[i].toUpperCase(Locale.ENGLISH))) {
                            manEntry = getJarEntry(names[i]);
                            break;
                        }
                    }
                }
            }
            if (manEntry != null) {
                byte[] b = new byte[(int)manEntry.getSize()];
                DataInputStream dis = new DataInputStream(
                                                          super.getInputStream(manEntry));
                dis.readFully(b, 0, b.length);
                dis.close();
 
                int last = b.length - src.length;
                int i = 0;
                next:       
                while (i<=last) {
                    for (int j=9; j>=0; j--) {
                        char c = (char) b[i+j];
                        c = (((c-'A')|('Z'-c)) >= 0) ? (char)(c + 32) : c;
                        if (c != src[j]) {
                            i += Math.max(j + 1 - lastOcc[c&0x7F], optoSft[j]);
                            continue next;
                        }
                    }
                    hasClassPathAttribute = true;
                    break;
                }
            }
        }
        computedHasClassPathAttribute = true;
        return hasClassPathAttribute;
    }

    private static String javaHome;
    private boolean isKnownToNotHaveClassPathAttribute() {
        // Optimize away even scanning of manifest for jar files we
        // deliver which don't have a class-path attribute. If one of
        // these jars is changed to include such an attribute this code
        // must be changed.
        if (javaHome == null) {
            javaHome = (String) AccessController.doPrivileged(
                new GetPropertyAction("java.home"));
        }
        String name = getName();
        String localJavaHome = javaHome;
        if (name.startsWith(localJavaHome)) {
            if (name.endsWith("rt.jar") ||
                name.endsWith("sunrsasign.jar") ||
                name.endsWith("jsse.jar") ||
                name.endsWith("jce.jar") ||
                name.endsWith("charsets.jar") ||
                name.endsWith("dnsns.jar") ||
                name.endsWith("ldapsec.jar") ||
                name.endsWith("localedata.jar") ||
                name.endsWith("sunjce_provider.jar")) {
                return true;
            }
        }
        return false;
    }
}