de.schlichtherle.truezip.nio.file.TPathScanner Maven / Gradle / Ivy
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/*
* Copyright (C) 2005-2015 Schlichtherle IT Services.
* All rights reserved. Use is subject to license terms.
*/
package de.schlichtherle.truezip.nio.file;
import static de.schlichtherle.truezip.entry.EntryName.SEPARATOR;
import static de.schlichtherle.truezip.entry.EntryName.SEPARATOR_CHAR;
import de.schlichtherle.truezip.file.TArchiveDetector;
import de.schlichtherle.truezip.fs.FsEntryName;
import static de.schlichtherle.truezip.fs.FsEntryName.ROOT;
import de.schlichtherle.truezip.fs.FsMountPoint;
import de.schlichtherle.truezip.fs.FsPath;
import de.schlichtherle.truezip.fs.FsScheme;
import static de.schlichtherle.truezip.fs.FsUriModifier.CANONICALIZE;
import static de.schlichtherle.truezip.fs.FsUriModifier.NULL;
import de.schlichtherle.truezip.io.Paths;
import de.schlichtherle.truezip.io.Paths.Splitter;
import de.schlichtherle.truezip.util.QuotedUriSyntaxException;
import de.schlichtherle.truezip.util.UriBuilder;
import java.net.URI;
import java.net.URISyntaxException;
import javax.annotation.Nullable;
import javax.annotation.concurrent.NotThreadSafe;
/**
* Scans hierarchical {@link URI}s for prospective archive files with the help
* of a {@link TArchiveDetector}.
*
* Note that this class has no dependencies on other classes in this package,
* so it could get published as a member of the package
* {@code de.schlichtherle.truezip.file} instead if required.
*
* @since TrueZIP 7.2
* @author Christian Schlichtherle
*/
@NotThreadSafe
final class TPathScanner {
static final URI SEPARATOR_URI = URI.create(SEPARATOR);
static final URI DOT_URI = URI.create(".");
static final URI DOT_DOT_URI = URI.create("..");
static final String DOT_DOT_SEPARATOR = ".." + SEPARATOR_CHAR;
private final TArchiveDetector detector;
private final Splitter splitter = new Splitter(SEPARATOR_CHAR, false);
private FsPath root;
private String memberQuery;
private final UriBuilder uri = new UriBuilder();
/**
* Constructs a new URI scanner which uses the given
* {@link TArchiveDetector}.
*
* @param detector the archive detector to use.
*/
TPathScanner(TArchiveDetector detector) {
assert null != detector;
this.detector = detector;
}
/**
* Constructs a new {@link FsPath} from the given {@code parent} and scans
* the given {@code member} for prospective archive files.
*
* {@code member} must not be opaque and must not define a fragment
* component.
* A scheme component gets ignored.
* If an authority component or an absolute path is present, the authority
* and path components of {@code parent} get discarded.
* An authority component gets copied to the result.
* A path component gets normalized and scanned for prospective archive
* files using the {@link TArchiveDetector} provided to the constructor and
* rewritten according to the syntax constraints for an {@link FsPath}.
* {@code ".."} segments at the beginning of the normalized path component
* are resolved against the scheme specific part of {@code parent}
* according to the syntax constraints for an {@link FsPath}.
* A query component is copied to the result.
*
* @param parent the file system path to use as the parent.
* @param member the URI to scan for prospective archive files.
* @return the file system path combined from the given {@code parent} and
* {@code member}, possibly decorated as an opaque URI to address
* prospective archive files.
* @throws IllegalArgumentException if any precondition is violated.
*/
FsPath scan(FsPath parent, URI member) {
try {
member = checkFix(member.normalize());
String mp;
while ((mp = member.getPath()).startsWith(DOT_DOT_SEPARATOR)) {
parent = parent(parent);
member = new UriBuilder(member)
.path(mp.substring(3))
.getUri();
}
if ("..".equals(mp))
return parent(parent);
final int mpl = pathPrefixLength(member);
if (0 < mpl) {
final URI pu = parent.toHierarchicalUri().resolve(SEPARATOR_URI);
final String ma = member.getAuthority();
final String p = null != ma || mp.startsWith(SEPARATOR)
? mp.substring(0, mpl)
: pu.getPath() + mp.substring(0, mpl);
this.root = new FsPath(
new UriBuilder()
.scheme(pu.getScheme())
.authority(ma)
.path(p)
.getUri());
mp = mp.substring(mpl);
} else {
this.root = parent;
}
this.memberQuery = member.getQuery();
return scan(mp);
} catch (URISyntaxException ex) {
throw new IllegalArgumentException(ex);
}
}
private FsPath scan(final String path) throws URISyntaxException {
splitter.split(path);
final String ps = splitter.getParentPath();
final FsEntryName men;
final FsPath pp;
if (null != ps) {
men = new FsEntryName(
uri.path(splitter.getMemberName()).getUri(),
NULL);
pp = scan(ps);
} else {
men = new FsEntryName(
uri.path(path).query(memberQuery).getUri(),
CANONICALIZE);
pp = root;
}
URI ppu;
FsPath mp;
if (men.isRoot() || (ppu = pp.toUri()).isOpaque() || !ppu.isAbsolute()) {
mp = pp.resolve(men);
} else {
final String pup = ppu.getPath();
if (!pup.endsWith(SEPARATOR))
ppu = new UriBuilder(ppu).path(pup + SEPARATOR_CHAR).getUri();
mp = new FsPath(new FsMountPoint(ppu), men);
}
final FsScheme s = detector.getScheme(men.toString());
if (null != s)
mp = new FsPath(new FsMountPoint(s, mp), ROOT);
return mp;
}
static int pathPrefixLength(final URI uri) {
final String ssp = uri.getSchemeSpecificPart();
final String a = uri.getAuthority();
final int al = null == a ? 0 : 2 + a.length();
final int pl = Paths.prefixLength(ssp, SEPARATOR_CHAR, true) - al;
return pl >= 0 ? pl : Paths.prefixLength(uri.getPath(), SEPARATOR_CHAR, false);
}
static URI checkFix(final URI uri) throws URISyntaxException {
if (uri.isOpaque())
throw new QuotedUriSyntaxException(uri, "Opaque URI");
if (null != uri.getFragment())
throw new QuotedUriSyntaxException(uri, "Fragment component defined");
return fixChecked(uri);
}
static URI fixUnchecked(final URI uri) {
return uri.isOpaque() ? uri : fixChecked(uri);
}
private static URI fixChecked(final URI uri) {
final String ssp = uri.getSchemeSpecificPart();
final String a = uri.getAuthority();
if (null == ssp // URI bug: null == new URI("foo").resolve(new URI("..")).getRawSchemeSpecificPart()
|| null == a && ssp.startsWith(SEPARATOR + SEPARATOR)) // empty authority
return new UriBuilder(uri).toUri();
return uri;
}
/**
* Returns whether or not the given path is absolute.
*
* A path is absolute if it doesn't need to be combined with other path
* information in order to locate a file.
*
* @return Whether or not the given path is absolute.
*/
static boolean isAbsolute(URI uri) {
return uri.isAbsolute() || Paths.isAbsolute(
uri.getSchemeSpecificPart(), SEPARATOR_CHAR);
}
/**
* Returns the parent of the given file system path.
*
* @param path a file system path.
* @return The parent file system path.
* @throws URISyntaxException
*/
static @Nullable FsPath parent(FsPath path) throws URISyntaxException {
FsMountPoint mp = path.getMountPoint();
FsEntryName en = path.getEntryName();
if (en.isRoot()) {
if (null == mp)
return null;
path = mp.getPath();
if (null != path)
return parent(path);
URI mpu = mp.toUri();
URI pu = mpu.resolve(DOT_DOT_URI);
if (mpu.getRawPath().length() <= pu.getRawPath().length())
return null;
return new FsPath(pu);
} else {
URI pu = en.toUri().resolve(DOT_URI);
en = new FsEntryName(pu, CANONICALIZE);
return new FsPath(mp, en);
}
}
}