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- /*
- * 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 {
- /**
- * References to convert into a reftable
- *
- * @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(buf)
- .setConfig(cfg)
- .begin()
- .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;
-
- /**
- * Whether deleted references will be returned.
- *
- * @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;
- }
-
- /**
- * Get the maximum update index for ref entries that appear in this
- * reftable.
- *
- * @return the maximum update index for ref entries that appear in this
- * reftable.
- * @throws java.io.IOException
- * file cannot be read.
- */
- public abstract long maxUpdateIndex() throws IOException;
-
- /**
- * Get the minimum update index for ref entries that appear in this
- * reftable.
- *
- * @return the minimum update index for ref entries that appear in this
- * reftable.
- * @throws java.io.IOException
- * file cannot be read.
- */
- public abstract long minUpdateIndex() throws IOException;
-
- /**
- * Seek to the first reference, to iterate in order.
- *
- * @return cursor to iterate.
- * @throws java.io.IOException
- * if references cannot be read.
- */
- public abstract RefCursor allRefs() throws IOException;
-
- /**
- * Seek to a reference.
- * <p>
- * This method will seek to the reference {@code refName}. If present, the
- * returned cursor will iterate exactly one entry. If not found, an empty
- * cursor is returned.
- *
- * @param refName
- * reference name.
- * @return cursor to iterate; empty cursor if no references match.
- * @throws java.io.IOException
- * if references cannot be read.
- */
- public abstract RefCursor seekRef(String refName) throws IOException;
-
- /**
- * Seek references with prefix.
- * <p>
- * The method will seek all the references starting with {@code prefix} as a
- * prefix. If no references start with this prefix, an empty cursor is
- * returned.
- *
- * @param prefix
- * prefix to find.
- * @return cursor to iterate; empty cursor if no references match.
- * @throws java.io.IOException
- * if references cannot be read.
- */
- public abstract RefCursor seekRefsWithPrefix(String prefix) 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 java.io.IOException
- * if references cannot be read.
- */
- public abstract RefCursor byObjectId(AnyObjectId id) throws IOException;
-
- /**
- * @return whether this reftable can do a fast SHA1 => ref lookup.
- * @throws IOException on I/O problems.
- */
- public abstract boolean hasObjectMap() throws IOException;
-
- /**
- * Seek reader to read log records.
- *
- * @return cursor to iterate; empty cursor if no logs are present.
- * @throws java.io.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 java.io.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 java.io.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 java.io.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 exists.
- *
- * @param refName
- * reference name or subtree to find.
- * @return {@code true} if the reference exists.
- * @throws java.io.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 starts with {@code prefix} as a prefix.
- *
- * @param prefix
- * prefix to find.
- * @return {@code true} if at least one reference exists with prefix.
- * @throws java.io.IOException
- * if references cannot be read.
- */
- public boolean hasRefsWithPrefix(String prefix) throws IOException {
- try (RefCursor rc = seekRefsWithPrefix(prefix)) {
- 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 java.io.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 java.io.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, ref.getUpdateIndex());
- }
- }
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