| /* |
| * Copyright (C) 2010, Google Inc. and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.lib; |
| |
| import java.io.IOException; |
| import java.util.ArrayList; |
| import java.util.Collection; |
| import java.util.Iterator; |
| import java.util.List; |
| import java.util.Set; |
| |
| import org.eclipse.jgit.annotations.Nullable; |
| import org.eclipse.jgit.errors.IncorrectObjectTypeException; |
| import org.eclipse.jgit.errors.MissingObjectException; |
| |
| /** |
| * Reads an {@link org.eclipse.jgit.lib.ObjectDatabase} for a single thread. |
| * <p> |
| * Readers that can support efficient reuse of pack encoded objects should also |
| * implement the companion interface |
| * {@link org.eclipse.jgit.internal.storage.pack.ObjectReuseAsIs}. |
| */ |
| public abstract class ObjectReader implements AutoCloseable { |
| /** Type hint indicating the caller doesn't know the type. */ |
| public static final int OBJ_ANY = -1; |
| |
| /** |
| * The threshold at which a file will be streamed rather than loaded |
| * entirely into memory. |
| * @since 4.6 |
| */ |
| protected int streamFileThreshold; |
| |
| /** |
| * Construct a new reader from the same data. |
| * <p> |
| * Applications can use this method to build a new reader from the same data |
| * source, but for an different thread. |
| * |
| * @return a brand new reader, using the same data source. |
| */ |
| public abstract ObjectReader newReader(); |
| |
| /** |
| * Obtain a unique abbreviation (prefix) of an object SHA-1. |
| * |
| * This method uses a reasonable default for the minimum length. Callers who |
| * don't care about the minimum length should prefer this method. |
| * |
| * The returned abbreviation would expand back to the argument ObjectId when |
| * passed to {@link #resolve(AbbreviatedObjectId)}, assuming no new objects |
| * are added to this repository between calls. |
| * |
| * @param objectId |
| * object identity that needs to be abbreviated. |
| * @return SHA-1 abbreviation. |
| * @throws java.io.IOException |
| * the object store cannot be read. |
| */ |
| public AbbreviatedObjectId abbreviate(AnyObjectId objectId) |
| throws IOException { |
| return abbreviate(objectId, 7); |
| } |
| |
| /** |
| * Obtain a unique abbreviation (prefix) of an object SHA-1. |
| * |
| * The returned abbreviation would expand back to the argument ObjectId when |
| * passed to {@link #resolve(AbbreviatedObjectId)}, assuming no new objects |
| * are added to this repository between calls. |
| * |
| * The default implementation of this method abbreviates the id to the |
| * minimum length, then resolves it to see if there are multiple results. |
| * When multiple results are found, the length is extended by 1 and resolve |
| * is tried again. |
| * |
| * @param objectId |
| * object identity that needs to be abbreviated. |
| * @param len |
| * minimum length of the abbreviated string. Must be in the range |
| * [2, {@value Constants#OBJECT_ID_STRING_LENGTH}]. |
| * @return SHA-1 abbreviation. If no matching objects exist in the |
| * repository, the abbreviation will match the minimum length. |
| * @throws java.io.IOException |
| * the object store cannot be read. |
| */ |
| public AbbreviatedObjectId abbreviate(AnyObjectId objectId, int len) |
| throws IOException { |
| if (len == Constants.OBJECT_ID_STRING_LENGTH) |
| return AbbreviatedObjectId.fromObjectId(objectId); |
| |
| AbbreviatedObjectId abbrev = objectId.abbreviate(len); |
| Collection<ObjectId> matches = resolve(abbrev); |
| while (1 < matches.size() && len < Constants.OBJECT_ID_STRING_LENGTH) { |
| abbrev = objectId.abbreviate(++len); |
| List<ObjectId> n = new ArrayList<>(8); |
| for (ObjectId candidate : matches) { |
| if (abbrev.prefixCompare(candidate) == 0) |
| n.add(candidate); |
| } |
| if (1 < n.size()) |
| matches = n; |
| else |
| matches = resolve(abbrev); |
| } |
| return abbrev; |
| } |
| |
| /** |
| * Resolve an abbreviated ObjectId to its full form. |
| * |
| * This method searches for an ObjectId that begins with the abbreviation, |
| * and returns at least some matching candidates. |
| * |
| * If the returned collection is empty, no objects start with this |
| * abbreviation. The abbreviation doesn't belong to this repository, or the |
| * repository lacks the necessary objects to complete it. |
| * |
| * If the collection contains exactly one member, the abbreviation is |
| * (currently) unique within this database. There is a reasonably high |
| * probability that the returned id is what was previously abbreviated. |
| * |
| * If the collection contains 2 or more members, the abbreviation is not |
| * unique. In this case the implementation is only required to return at |
| * least 2 candidates to signal the abbreviation has conflicts. User |
| * friendly implementations should return as many candidates as reasonably |
| * possible, as the caller may be able to disambiguate further based on |
| * context. However since databases can be very large (e.g. 10 million |
| * objects) returning 625,000 candidates for the abbreviation "0" is simply |
| * unreasonable, so implementors should draw the line at around 256 matches. |
| * |
| * @param id |
| * abbreviated id to resolve to a complete identity. The |
| * abbreviation must have a length of at least 2. |
| * @return candidates that begin with the abbreviated identity. |
| * @throws java.io.IOException |
| * the object store cannot be read. |
| */ |
| public abstract Collection<ObjectId> resolve(AbbreviatedObjectId id) |
| throws IOException; |
| |
| /** |
| * Does the requested object exist in this database? |
| * |
| * @param objectId |
| * identity of the object to test for existence of. |
| * @return true if the specified object is stored in this database. |
| * @throws java.io.IOException |
| * the object store cannot be accessed. |
| */ |
| public boolean has(AnyObjectId objectId) throws IOException { |
| return has(objectId, OBJ_ANY); |
| } |
| |
| /** |
| * Does the requested object exist in this database? |
| * |
| * @param objectId |
| * identity of the object to test for existence of. |
| * @param typeHint |
| * hint about the type of object being requested, e.g. |
| * {@link org.eclipse.jgit.lib.Constants#OBJ_BLOB}; |
| * {@link #OBJ_ANY} if the object type is not known, or does not |
| * matter to the caller. |
| * @return true if the specified object is stored in this database. |
| * @throws IncorrectObjectTypeException |
| * typeHint was not OBJ_ANY, and the object's actual type does |
| * not match typeHint. |
| * @throws java.io.IOException |
| * the object store cannot be accessed. |
| */ |
| public boolean has(AnyObjectId objectId, int typeHint) throws IOException { |
| try { |
| open(objectId, typeHint); |
| return true; |
| } catch (MissingObjectException notFound) { |
| return false; |
| } |
| } |
| |
| /** |
| * Open an object from this database. |
| * |
| * @param objectId |
| * identity of the object to open. |
| * @return a {@link org.eclipse.jgit.lib.ObjectLoader} for accessing the |
| * object. |
| * @throws org.eclipse.jgit.errors.MissingObjectException |
| * the object does not exist. |
| * @throws java.io.IOException |
| * the object store cannot be accessed. |
| */ |
| public ObjectLoader open(AnyObjectId objectId) |
| throws MissingObjectException, IOException { |
| return open(objectId, OBJ_ANY); |
| } |
| |
| /** |
| * Open an object from this database. |
| * |
| * @param objectId |
| * identity of the object to open. |
| * @param typeHint |
| * hint about the type of object being requested, e.g. |
| * {@link org.eclipse.jgit.lib.Constants#OBJ_BLOB}; |
| * {@link #OBJ_ANY} if the object type is not known, or does not |
| * matter to the caller. |
| * @return a {@link org.eclipse.jgit.lib.ObjectLoader} for accessing the |
| * object. |
| * @throws org.eclipse.jgit.errors.MissingObjectException |
| * the object does not exist. |
| * @throws org.eclipse.jgit.errors.IncorrectObjectTypeException |
| * typeHint was not OBJ_ANY, and the object's actual type does |
| * not match typeHint. |
| * @throws java.io.IOException |
| * the object store cannot be accessed. |
| */ |
| public abstract ObjectLoader open(AnyObjectId objectId, int typeHint) |
| throws MissingObjectException, IncorrectObjectTypeException, |
| IOException; |
| |
| /** |
| * Returns IDs for those commits which should be considered as shallow. |
| * |
| * @return IDs of shallow commits |
| * @throws java.io.IOException |
| */ |
| public abstract Set<ObjectId> getShallowCommits() throws IOException; |
| |
| /** |
| * Asynchronous object opening. |
| * |
| * @param objectIds |
| * objects to open from the object store. The supplied collection |
| * must not be modified until the queue has finished. |
| * @param reportMissing |
| * if true missing objects are reported by calling failure with a |
| * MissingObjectException. This may be more expensive for the |
| * implementation to guarantee. If false the implementation may |
| * choose to report MissingObjectException, or silently skip over |
| * the object with no warning. |
| * @return queue to read the objects from. |
| */ |
| public <T extends ObjectId> AsyncObjectLoaderQueue<T> open( |
| Iterable<T> objectIds, final boolean reportMissing) { |
| final Iterator<T> idItr = objectIds.iterator(); |
| return new AsyncObjectLoaderQueue<T>() { |
| private T cur; |
| |
| @Override |
| public boolean next() throws MissingObjectException, IOException { |
| if (idItr.hasNext()) { |
| cur = idItr.next(); |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| public T getCurrent() { |
| return cur; |
| } |
| |
| @Override |
| public ObjectId getObjectId() { |
| return cur; |
| } |
| |
| @Override |
| public ObjectLoader open() throws IOException { |
| return ObjectReader.this.open(cur, OBJ_ANY); |
| } |
| |
| @Override |
| public boolean cancel(boolean mayInterruptIfRunning) { |
| return true; |
| } |
| |
| @Override |
| public void release() { |
| // Since we are sequential by default, we don't |
| // have any state to clean up if we terminate early. |
| } |
| }; |
| } |
| |
| /** |
| * Get only the size of an object. |
| * <p> |
| * The default implementation of this method opens an ObjectLoader. |
| * Databases are encouraged to override this if a faster access method is |
| * available to them. |
| * |
| * @param objectId |
| * identity of the object to open. |
| * @param typeHint |
| * hint about the type of object being requested, e.g. |
| * {@link org.eclipse.jgit.lib.Constants#OBJ_BLOB}; |
| * {@link #OBJ_ANY} if the object type is not known, or does not |
| * matter to the caller. |
| * @return size of object in bytes. |
| * @throws org.eclipse.jgit.errors.MissingObjectException |
| * the object does not exist. |
| * @throws org.eclipse.jgit.errors.IncorrectObjectTypeException |
| * typeHint was not OBJ_ANY, and the object's actual type does |
| * not match typeHint. |
| * @throws java.io.IOException |
| * the object store cannot be accessed. |
| */ |
| public long getObjectSize(AnyObjectId objectId, int typeHint) |
| throws MissingObjectException, IncorrectObjectTypeException, |
| IOException { |
| return open(objectId, typeHint).getSize(); |
| } |
| |
| /** |
| * Asynchronous object size lookup. |
| * |
| * @param objectIds |
| * objects to get the size of from the object store. The supplied |
| * collection must not be modified until the queue has finished. |
| * @param reportMissing |
| * if true missing objects are reported by calling failure with a |
| * MissingObjectException. This may be more expensive for the |
| * implementation to guarantee. If false the implementation may |
| * choose to report MissingObjectException, or silently skip over |
| * the object with no warning. |
| * @return queue to read object sizes from. |
| */ |
| public <T extends ObjectId> AsyncObjectSizeQueue<T> getObjectSize( |
| Iterable<T> objectIds, final boolean reportMissing) { |
| final Iterator<T> idItr = objectIds.iterator(); |
| return new AsyncObjectSizeQueue<T>() { |
| private T cur; |
| |
| private long sz; |
| |
| @Override |
| public boolean next() throws MissingObjectException, IOException { |
| if (idItr.hasNext()) { |
| cur = idItr.next(); |
| sz = getObjectSize(cur, OBJ_ANY); |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| public T getCurrent() { |
| return cur; |
| } |
| |
| @Override |
| public ObjectId getObjectId() { |
| return cur; |
| } |
| |
| @Override |
| public long getSize() { |
| return sz; |
| } |
| |
| @Override |
| public boolean cancel(boolean mayInterruptIfRunning) { |
| return true; |
| } |
| |
| @Override |
| public void release() { |
| // Since we are sequential by default, we don't |
| // have any state to clean up if we terminate early. |
| } |
| }; |
| } |
| |
| /** |
| * Advise the reader to avoid unreachable objects. |
| * <p> |
| * While enabled the reader will skip over anything previously proven to be |
| * unreachable. This may be dangerous in the face of concurrent writes. |
| * |
| * @param avoid |
| * true to avoid unreachable objects. |
| * @since 3.0 |
| */ |
| public void setAvoidUnreachableObjects(boolean avoid) { |
| // Do nothing by default. |
| } |
| |
| /** |
| * An index that can be used to speed up ObjectWalks. |
| * |
| * @return the index or null if one does not exist. |
| * @throws java.io.IOException |
| * when the index fails to load |
| * @since 3.0 |
| */ |
| public BitmapIndex getBitmapIndex() throws IOException { |
| return null; |
| } |
| |
| /** |
| * Get the {@link org.eclipse.jgit.lib.ObjectInserter} from which this |
| * reader was created using {@code inserter.newReader()} |
| * |
| * @return the {@link org.eclipse.jgit.lib.ObjectInserter} from which this |
| * reader was created using {@code inserter.newReader()}, or null if |
| * this reader was not created from an inserter. |
| * @since 4.4 |
| */ |
| @Nullable |
| public ObjectInserter getCreatedFromInserter() { |
| return null; |
| } |
| |
| /** |
| * {@inheritDoc} |
| * <p> |
| * Release any resources used by this reader. |
| * <p> |
| * A reader that has been released can be used again, but may need to be |
| * released after the subsequent usage. |
| * |
| * @since 4.0 |
| */ |
| @Override |
| public abstract void close(); |
| |
| /** |
| * Sets the threshold at which a file will be streamed rather than loaded |
| * entirely into memory |
| * |
| * @param threshold |
| * the new threshold |
| * @since 4.6 |
| */ |
| public void setStreamFileThreshold(int threshold) { |
| streamFileThreshold = threshold; |
| } |
| |
| /** |
| * Returns the threshold at which a file will be streamed rather than loaded |
| * entirely into memory |
| * |
| * @return the threshold in bytes |
| * @since 4.6 |
| */ |
| public int getStreamFileThreshold() { |
| return streamFileThreshold; |
| } |
| |
| /** |
| * Wraps a delegate ObjectReader. |
| * |
| * @since 4.4 |
| */ |
| public static abstract class Filter extends ObjectReader { |
| /** |
| * @return delegate ObjectReader to handle all processing. |
| * @since 4.4 |
| */ |
| protected abstract ObjectReader delegate(); |
| |
| @Override |
| public ObjectReader newReader() { |
| return delegate().newReader(); |
| } |
| |
| @Override |
| public AbbreviatedObjectId abbreviate(AnyObjectId objectId) |
| throws IOException { |
| return delegate().abbreviate(objectId); |
| } |
| |
| @Override |
| public AbbreviatedObjectId abbreviate(AnyObjectId objectId, int len) |
| throws IOException { |
| return delegate().abbreviate(objectId, len); |
| } |
| |
| @Override |
| public Collection<ObjectId> resolve(AbbreviatedObjectId id) |
| throws IOException { |
| return delegate().resolve(id); |
| } |
| |
| @Override |
| public boolean has(AnyObjectId objectId) throws IOException { |
| return delegate().has(objectId); |
| } |
| |
| @Override |
| public boolean has(AnyObjectId objectId, int typeHint) throws IOException { |
| return delegate().has(objectId, typeHint); |
| } |
| |
| @Override |
| public ObjectLoader open(AnyObjectId objectId) |
| throws MissingObjectException, IOException { |
| return delegate().open(objectId); |
| } |
| |
| @Override |
| public ObjectLoader open(AnyObjectId objectId, int typeHint) |
| throws MissingObjectException, IncorrectObjectTypeException, |
| IOException { |
| return delegate().open(objectId, typeHint); |
| } |
| |
| @Override |
| public Set<ObjectId> getShallowCommits() throws IOException { |
| return delegate().getShallowCommits(); |
| } |
| |
| @Override |
| public <T extends ObjectId> AsyncObjectLoaderQueue<T> open( |
| Iterable<T> objectIds, boolean reportMissing) { |
| return delegate().open(objectIds, reportMissing); |
| } |
| |
| @Override |
| public long getObjectSize(AnyObjectId objectId, int typeHint) |
| throws MissingObjectException, IncorrectObjectTypeException, |
| IOException { |
| return delegate().getObjectSize(objectId, typeHint); |
| } |
| |
| @Override |
| public <T extends ObjectId> AsyncObjectSizeQueue<T> getObjectSize( |
| Iterable<T> objectIds, boolean reportMissing) { |
| return delegate().getObjectSize(objectIds, reportMissing); |
| } |
| |
| @Override |
| public void setAvoidUnreachableObjects(boolean avoid) { |
| delegate().setAvoidUnreachableObjects(avoid); |
| } |
| |
| @Override |
| public BitmapIndex getBitmapIndex() throws IOException { |
| return delegate().getBitmapIndex(); |
| } |
| |
| @Override |
| @Nullable |
| public ObjectInserter getCreatedFromInserter() { |
| return delegate().getCreatedFromInserter(); |
| } |
| |
| @Override |
| public void close() { |
| delegate().close(); |
| } |
| } |
| } |