org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/reftable/Reftable.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2017, Google Inc.
  * and other copyright owners as documented in the project's IP log.
  *
  * This program and the accompanying materials are made available
  * under the terms of the Eclipse Distribution License v1.0 which
  * accompanies this distribution, is reproduced below, and is
  * available at http://www.eclipse.org/org/documents/edl-v10.php
  *
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or
  * without modification, are permitted provided that the following
  * conditions are met:
  *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  *
  * - Redistributions in binary form must reproduce the above
  *   copyright notice, this list of conditions and the following
  *   disclaimer in the documentation and/or other materials provided
  *   with the distribution.
  *
  * - Neither the name of the Eclipse Foundation, Inc. nor the
  *   names of its contributors may be used to endorse or promote
  *   products derived from this software without specific prior
  *   written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
  * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
  * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 package org.eclipse.jgit.internal.storage.reftable;

 import static org.eclipse.jgit.lib.RefDatabase.MAX_SYMBOLIC_REF_DEPTH;

 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Collection;

 import org.eclipse.jgit.annotations.Nullable;
 import org.eclipse.jgit.internal.storage.io.BlockSource;
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.SymbolicRef;

 /** Abstract table of references. */
 public abstract class Reftable implements AutoCloseable {
 	/**
 	 * @param refs
 	 *            references to convert into a reftable; may be empty.
 	 * @return a reader for the supplied references.
 	 */
 	public static Reftable from(Collection<Ref> refs) {
 		try {
 			ReftableConfig cfg = new ReftableConfig();
 			cfg.setIndexObjects(false);
 			cfg.setAlignBlocks(false);
 			ByteArrayOutputStream buf = new ByteArrayOutputStream();
 			new ReftableWriter()
 				.setConfig(cfg)
 				.begin(buf)
 				.sortAndWriteRefs(refs)
 				.finish();
 			return new ReftableReader(BlockSource.from(buf.toByteArray()));
 		} catch (IOException e) {
 			throw new RuntimeException(e);
 		}
 	}

 	/** {@code true} if deletions should be included in results. */
 	protected boolean includeDeletes;

 	/**
 	 * @param deletes
 	 *            if {@code true} deleted references will be returned. If
 	 *            {@code false} (default behavior), deleted references will be
 	 *            skipped, and not returned.
 	 */
 	public void setIncludeDeletes(boolean deletes) {
 		includeDeletes = deletes;
 	}

 	/**
 	 * Seek to the first reference, to iterate in order.
 	 *
 	 * @return cursor to iterate.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	public abstract RefCursor allRefs() throws IOException;

 	/**
 	 * Seek either to a reference, or a reference subtree.
 	 * <p>
 	 * If {@code refName} ends with {@code "/"} the method will seek to the
 	 * subtree of all references starting with {@code refName} as a prefix. If
 	 * no references start with this prefix, an empty cursor is returned.
 	 * <p>
 	 * Otherwise exactly {@code refName} will be looked for. If present, the
 	 * returned cursor will iterate exactly one entry. If not found, an empty
 	 * cursor is returned.
 	 *
 	 * @param refName
 	 *            reference name or subtree to find.
 	 * @return cursor to iterate; empty cursor if no references match.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	public abstract RefCursor seekRef(String refName) throws IOException;

 	/**
 	 * Match references pointing to a specific object.
 	 *
 	 * @param id
 	 *            object to find.
 	 * @return cursor to iterate; empty cursor if no references match.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	public abstract RefCursor byObjectId(AnyObjectId id) throws IOException;

 	/**
 	 * Seek reader to read log records.
 	 *
 	 * @return cursor to iterate; empty cursor if no logs are present.
 	 * @throws IOException
 	 *             if logs cannot be read.
 	 */
 	public abstract LogCursor allLogs() throws IOException;

 	/**
 	 * Read a single reference's log.
 	 *
 	 * @param refName
 	 *            exact name of the reference whose log to read.
 	 * @return cursor to iterate; empty cursor if no logs match.
 	 * @throws IOException
 	 *             if logs cannot be read.
 	 */
 	public LogCursor seekLog(String refName) throws IOException {
 		return seekLog(refName, Long.MAX_VALUE);
 	}

 	/**
 	 * Seek to an update index in a reference's log.
 	 *
 	 * @param refName
 	 *            exact name of the reference whose log to read.
 	 * @param updateIndex
 	 *            most recent index to return first in the log cursor. Log
 	 *            records at or before {@code updateIndex} will be returned.
 	 * @return cursor to iterate; empty cursor if no logs match.
 	 * @throws IOException
 	 *             if logs cannot be read.
 	 */
 	public abstract LogCursor seekLog(String refName, long updateIndex)
 			throws IOException;

 	/**
 	 * Lookup a reference, or null if not found.
 	 *
 	 * @param refName
 	 *            reference name to find.
 	 * @return the reference, or {@code null} if not found.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	@Nullable
 	public Ref exactRef(String refName) throws IOException {
 		try (RefCursor rc = seekRef(refName)) {
 			return rc.next() ? rc.getRef() : null;
 		}
 	}

 	/**
 	 * Test if a reference or reference subtree exists.
 	 * <p>
 	 * If {@code refName} ends with {@code "/"}, the method tests if any
 	 * reference starts with {@code refName} as a prefix.
 	 * <p>
 	 * Otherwise, the method checks if {@code refName} exists.
 	 *
 	 * @param refName
 	 *            reference name or subtree to find.
 	 * @return {@code true} if the reference exists, or at least one reference
 	 *         exists in the subtree.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	public boolean hasRef(String refName) throws IOException {
 		try (RefCursor rc = seekRef(refName)) {
 			return rc.next();
 		}
 	}

 	/**
 	 * Test if any reference directly refers to the object.
 	 *
 	 * @param id
 	 *            ObjectId to find.
 	 * @return {@code true} if any reference exists directly referencing
 	 *         {@code id}, or a annotated tag that peels to {@code id}.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	public boolean hasId(AnyObjectId id) throws IOException {
 		try (RefCursor rc = byObjectId(id)) {
 			return rc.next();
 		}
 	}

 	/**
 	 * Resolve a symbolic reference to populate its value.
 	 *
 	 * @param symref
 	 *            reference to resolve.
 	 * @return resolved {@code symref}, or {@code null}.
 	 * @throws IOException
 	 *             if references cannot be read.
 	 */
 	@Nullable
 	public Ref resolve(Ref symref) throws IOException {
 		return resolve(symref, 0);
 	}

 	private Ref resolve(Ref ref, int depth) throws IOException {
 		if (!ref.isSymbolic()) {
 			return ref;
 		}

 		Ref dst = ref.getTarget();
 		if (MAX_SYMBOLIC_REF_DEPTH <= depth) {
 			return null; // claim it doesn't exist
 		}

 		dst = exactRef(dst.getName());
 		if (dst == null) {
 			return ref;
 		}

 		dst = resolve(dst, depth + 1);
 		if (dst == null) {
 			return null; // claim it doesn't exist
 		}
 		return new SymbolicRef(ref.getName(), dst);
 	}

 	@Override
 	public abstract void close() throws IOException;
 }
	/*
	* Copyright (C) 2017, Google Inc.
	* and other copyright owners as documented in the project's IP log.
	*
	* This program and the accompanying materials are made available
	* under the terms of the Eclipse Distribution License v1.0 which
	* accompanies this distribution, is reproduced below, and is
	* available at http://www.eclipse.org/org/documents/edl-v10.php
	*
	* All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or
	* without modification, are permitted provided that the following
	* conditions are met:
	*
	* - Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	*
	* - Redistributions in binary form must reproduce the above
	* copyright notice, this list of conditions and the following
	* disclaimer in the documentation and/or other materials provided
	* with the distribution.
	*
	* - Neither the name of the Eclipse Foundation, Inc. nor the
	* names of its contributors may be used to endorse or promote
	* products derived from this software without specific prior
	* written permission.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
	* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
	* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
	* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
	* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
	* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	package org.eclipse.jgit.internal.storage.reftable;

	import static org.eclipse.jgit.lib.RefDatabase.MAX_SYMBOLIC_REF_DEPTH;

	import java.io.ByteArrayOutputStream;
	import java.io.IOException;
	import java.util.Collection;

	import org.eclipse.jgit.annotations.Nullable;
	import org.eclipse.jgit.internal.storage.io.BlockSource;
	import org.eclipse.jgit.lib.AnyObjectId;
	import org.eclipse.jgit.lib.Ref;
	import org.eclipse.jgit.lib.SymbolicRef;

	/** Abstract table of references. */
	public abstract class Reftable implements AutoCloseable {
	/**
	* @param refs
	* references to convert into a reftable; may be empty.
	* @return a reader for the supplied references.
	*/
	public static Reftable from(Collection<Ref> refs) {
	try {
	ReftableConfig cfg = new ReftableConfig();
	cfg.setIndexObjects(false);
	cfg.setAlignBlocks(false);
	ByteArrayOutputStream buf = new ByteArrayOutputStream();
	new ReftableWriter()
	.setConfig(cfg)
	.begin(buf)
	.sortAndWriteRefs(refs)
	.finish();
	return new ReftableReader(BlockSource.from(buf.toByteArray()));
	} catch (IOException e) {
	throw new RuntimeException(e);
	}
	}

	/** {@code true} if deletions should be included in results. */
	protected boolean includeDeletes;

	/**
	* @param deletes
	* if {@code true} deleted references will be returned. If
	* {@code false} (default behavior), deleted references will be
	* skipped, and not returned.
	*/
	public void setIncludeDeletes(boolean deletes) {
	includeDeletes = deletes;
	}

	/**
	* Seek to the first reference, to iterate in order.
	*
	* @return cursor to iterate.
	* @throws IOException
	* if references cannot be read.
	*/
	public abstract RefCursor allRefs() throws IOException;

	/**
	* Seek either to a reference, or a reference subtree.
	* <p>
	* If {@code refName} ends with {@code "/"} the method will seek to the
	* subtree of all references starting with {@code refName} as a prefix. If
	* no references start with this prefix, an empty cursor is returned.
	* <p>
	* Otherwise exactly {@code refName} will be looked for. If present, the
	* returned cursor will iterate exactly one entry. If not found, an empty
	* cursor is returned.
	*
	* @param refName
	* reference name or subtree to find.
	* @return cursor to iterate; empty cursor if no references match.
	* @throws IOException
	* if references cannot be read.
	*/
	public abstract RefCursor seekRef(String refName) throws IOException;

	/**
	* Match references pointing to a specific object.
	*
	* @param id
	* object to find.
	* @return cursor to iterate; empty cursor if no references match.
	* @throws IOException
	* if references cannot be read.
	*/
	public abstract RefCursor byObjectId(AnyObjectId id) throws IOException;

	/**
	* Seek reader to read log records.
	*
	* @return cursor to iterate; empty cursor if no logs are present.
	* @throws IOException
	* if logs cannot be read.
	*/
	public abstract LogCursor allLogs() throws IOException;

	/**
	* Read a single reference's log.
	*
	* @param refName
	* exact name of the reference whose log to read.
	* @return cursor to iterate; empty cursor if no logs match.
	* @throws IOException
	* if logs cannot be read.
	*/
	public LogCursor seekLog(String refName) throws IOException {
	return seekLog(refName, Long.MAX_VALUE);
	}

	/**
	* Seek to an update index in a reference's log.
	*
	* @param refName
	* exact name of the reference whose log to read.
	* @param updateIndex
	* most recent index to return first in the log cursor. Log
	* records at or before {@code updateIndex} will be returned.
	* @return cursor to iterate; empty cursor if no logs match.
	* @throws IOException
	* if logs cannot be read.
	*/
	public abstract LogCursor seekLog(String refName, long updateIndex)
	throws IOException;

	/**
	* Lookup a reference, or null if not found.
	*
	* @param refName
	* reference name to find.
	* @return the reference, or {@code null} if not found.
	* @throws IOException
	* if references cannot be read.
	*/
	@Nullable
	public Ref exactRef(String refName) throws IOException {
	try (RefCursor rc = seekRef(refName)) {
	return rc.next() ? rc.getRef() : null;
	}
	}

	/**
	* Test if a reference or reference subtree exists.
	* <p>
	* If {@code refName} ends with {@code "/"}, the method tests if any
	* reference starts with {@code refName} as a prefix.
	* <p>
	* Otherwise, the method checks if {@code refName} exists.
	*
	* @param refName
	* reference name or subtree to find.
	* @return {@code true} if the reference exists, or at least one reference
	* exists in the subtree.
	* @throws IOException
	* if references cannot be read.
	*/
	public boolean hasRef(String refName) throws IOException {
	try (RefCursor rc = seekRef(refName)) {
	return rc.next();
	}
	}

	/**
	* Test if any reference directly refers to the object.
	*
	* @param id
	* ObjectId to find.
	* @return {@code true} if any reference exists directly referencing
	* {@code id}, or a annotated tag that peels to {@code id}.
	* @throws IOException
	* if references cannot be read.
	*/
	public boolean hasId(AnyObjectId id) throws IOException {
	try (RefCursor rc = byObjectId(id)) {
	return rc.next();
	}
	}

	/**
	* Resolve a symbolic reference to populate its value.
	*
	* @param symref
	* reference to resolve.
	* @return resolved {@code symref}, or {@code null}.
	* @throws IOException
	* if references cannot be read.
	*/
	@Nullable
	public Ref resolve(Ref symref) throws IOException {
	return resolve(symref, 0);
	}

	private Ref resolve(Ref ref, int depth) throws IOException {
	if (!ref.isSymbolic()) {
	return ref;
	}

	Ref dst = ref.getTarget();
	if (MAX_SYMBOLIC_REF_DEPTH <= depth) {
	return null; // claim it doesn't exist
	}

	dst = exactRef(dst.getName());
	if (dst == null) {
	return ref;
	}

	dst = resolve(dst, depth + 1);
	if (dst == null) {
	return null; // claim it doesn't exist
	}
	return new SymbolicRef(ref.getName(), dst);
	}

	@Override
	public abstract void close() throws IOException;
	}