/*
* Copyright (C) 2010, 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.
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package org.eclipse.jgit.notes;
import java.io.IOException;
import java.util.Iterator;
import org.eclipse.jgit.errors.CorruptObjectException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.LargeObjectException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.AbbreviatedObjectId;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.MutableObjectId;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.ObjectReader;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevTree;
/**
* Index of notes from a note branch.
*
* This class is not thread-safe, and relies on an {@link ObjectReader} that it
* borrows/shares with the caller. The reader can be used during any call, and
* is not released by this class. The caller should arrange for releasing the
* shared {@code ObjectReader} at the proper times.
*/
public class NoteMap implements Iterable<Note> {
/**
* Construct a new empty note map.
*
* @return an empty note map.
*/
public static NoteMap newEmptyMap() {
NoteMap r = new NoteMap(null /* no reader */);
r.root = new LeafBucket(0);
return r;
}
/**
* Shorten the note ref name by trimming off the {@link Constants#R_NOTES}
* prefix if it exists.
*
* @param noteRefName
* @return a more user friendly note name
*/
public static String shortenRefName(String noteRefName) {
if (noteRefName.startsWith(Constants.R_NOTES))
return noteRefName.substring(Constants.R_NOTES.length());
return noteRefName;
}
/**
* Load a collection of notes from a branch.
*
* @param reader
* reader to scan the note branch with. This reader may be
* retained by the NoteMap for the life of the map in order to
* support lazy loading of entries.
* @param commit
* the revision of the note branch to read.
* @return the note map read from the commit.
* @throws IOException
* the repository cannot be accessed through the reader.
* @throws CorruptObjectException
* a tree object is corrupt and cannot be read.
* @throws IncorrectObjectTypeException
* a tree object wasn't actually a tree.
* @throws MissingObjectException
* a reference tree object doesn't exist.
*/
public static NoteMap read(ObjectReader reader, RevCommit commit)
throws MissingObjectException, IncorrectObjectTypeException,
CorruptObjectException, IOException {
return read(reader, commit.getTree());
}
/**
* Load a collection of notes from a tree.
*
* @param reader
* reader to scan the note branch with. This reader may be
* retained by the NoteMap for the life of the map in order to
* support lazy loading of entries.
* @param tree
* the note tree to read.
* @return the note map read from the tree.
* @throws IOException
* the repository cannot be accessed through the reader.
* @throws CorruptObjectException
* a tree object is corrupt and cannot be read.
* @throws IncorrectObjectTypeException
* a tree object wasn't actually a tree.
* @throws MissingObjectException
* a reference tree object doesn't exist.
*/
public static NoteMap read(ObjectReader reader, RevTree tree)
throws MissingObjectException, IncorrectObjectTypeException,
CorruptObjectException, IOException {
return readTree(reader, tree);
}
/**
* Load a collection of notes from a tree.
*
* @param reader
* reader to scan the note branch with. This reader may be
* retained by the NoteMap for the life of the map in order to
* support lazy loading of entries.
* @param treeId
* the note tree to read.
* @return the note map read from the tree.
* @throws IOException
* the repository cannot be accessed through the reader.
* @throws CorruptObjectException
* a tree object is corrupt and cannot be read.
* @throws IncorrectObjectTypeException
* a tree object wasn't actually a tree.
* @throws MissingObjectException
* a reference tree object doesn't exist.
*/
public static NoteMap readTree(ObjectReader reader, ObjectId treeId)
throws MissingObjectException, IncorrectObjectTypeException,
CorruptObjectException, IOException {
NoteMap map = new NoteMap(reader);
map.load(treeId);
return map;
}
/**
* Construct a new note map from an existing note bucket.
*
* @param root
* the root bucket of this note map
* @param reader
* reader to scan the note branch with. This reader may be
* retained by the NoteMap for the life of the map in order to
* support lazy loading of entries.
* @return the note map built from the note bucket
*/
static NoteMap newMap(InMemoryNoteBucket root, ObjectReader reader) {
NoteMap map = new NoteMap(reader);
map.root = root;
return map;
}
/** Borrowed reader to access the repository. */
private final ObjectReader reader;
/** All of the notes that have been loaded. */
private InMemoryNoteBucket root;
private NoteMap(ObjectReader reader) {
this.reader = reader;
}
/**
* @return an iterator that iterates over notes of this NoteMap. Non note
* entries are ignored by this iterator.
*/
public Iterator<Note> iterator() {
try {
return root.iterator(new MutableObjectId(), reader);
} catch (IOException e) {
throw new RuntimeException(e);
}
}
/**
* Lookup a note for a specific ObjectId.
*
* @param id
* the object to look for.
* @return the note's blob ObjectId, or null if no note exists.
* @throws IOException
* a portion of the note space is not accessible.
*/
public ObjectId get(AnyObjectId id) throws IOException {
Note n = root.getNote(id, reader);
return n == null ? null : n.getData();
}
/**
* Lookup a note for a specific ObjectId.
*
* @param id
* the object to look for.
* @return the note for the given object id, or null if no note exists.
* @throws IOException
* a portion of the note space is not accessible.
*/
public Note getNote(AnyObjectId id) throws IOException {
return root.getNote(id, reader);
}
/**
* Determine if a note exists for the specified ObjectId.
*
* @param id
* the object to look for.
* @return true if a note exists; false if there is no note.
* @throws IOException
* a portion of the note space is not accessible.
*/
public boolean contains(AnyObjectId id) throws IOException {
return get(id) != null;
}
/**
* Open and return the content of an object's note.
*
* This method assumes the note is fairly small and can be accessed
* efficiently. Larger notes should be accessed by streaming:
*
* <pre>
* ObjectId dataId = thisMap.get(id);
* if (dataId != null)
* reader.open(dataId).openStream();
* </pre>
*
* @param id
* object to lookup the note of.
* @param sizeLimit
* maximum number of bytes to return. If the note data size is
* larger than this limit, LargeObjectException will be thrown.
* @return if a note is defined for {@code id}, the note content. If no note
* is defined, null.
* @throws LargeObjectException
* the note data is larger than {@code sizeLimit}.
* @throws MissingObjectException
* the note's blob does not exist in the repository.
* @throws IOException
* the note's blob cannot be read from the repository
*/
public byte[] getCachedBytes(AnyObjectId id, int sizeLimit)
throws LargeObjectException, MissingObjectException, IOException {
ObjectId dataId = get(id);
if (dataId != null)
return reader.open(dataId).getCachedBytes(sizeLimit);
else
return null;
}
/**
* Attach (or remove) a note on an object.
*
* If no note exists, a new note is stored. If a note already exists for the
* given object, it is replaced (or removed).
*
* This method only updates the map in memory.
*
* If the caller wants to attach a UTF-8 encoded string message to an
* object, {@link #set(AnyObjectId, String, ObjectInserter)} is a convenient
* way to encode and update a note in one step.
*
* @param noteOn
* the object to attach the note to. This same ObjectId can later
* be used as an argument to {@link #get(AnyObjectId)} or
* {@link #getCachedBytes(AnyObjectId, int)} to read back the
* {@code noteData}.
* @param noteData
* data to associate with the note. This must be the ObjectId of
* a blob that already exists in the repository. If null the note
* will be deleted, if present.
* @throws IOException
* a portion of the note space is not accessible.
*/
public void set(AnyObjectId noteOn, ObjectId noteData) throws IOException {
InMemoryNoteBucket newRoot = root.set(noteOn, noteData, reader);
if (newRoot == null) {
newRoot = new LeafBucket(0);
newRoot.nonNotes = root.nonNotes;
}
root = newRoot;
}
/**
* Attach a note to an object.
*
* If no note exists, a new note is stored. If a note already exists for the
* given object, it is replaced (or removed).
*
* @param noteOn
* the object to attach the note to. This same ObjectId can later
* be used as an argument to {@link #get(AnyObjectId)} or
* {@link #getCachedBytes(AnyObjectId, int)} to read back the
* {@code noteData}.
* @param noteData
* text to store in the note. The text will be UTF-8 encoded when
* stored in the repository. If null the note will be deleted, if
* the empty string a note with the empty string will be stored.
* @param ins
* inserter to write the encoded {@code noteData} out as a blob.
* The caller must ensure the inserter is flushed before the
* updated note map is made available for reading.
* @throws IOException
* the note data could not be stored in the repository.
*/
public void set(AnyObjectId noteOn, String noteData, ObjectInserter ins)
throws IOException {
ObjectId dataId;
if (noteData != null) {
byte[] dataUTF8 = Constants.encode(noteData);
dataId = ins.insert(Constants.OBJ_BLOB, dataUTF8);
} else {
dataId = null;
}
set(noteOn, dataId);
}
/**
* Remove a note from an object.
*
* If no note exists, no action is performed.
*
* This method only updates the map in memory.
*
* @param noteOn
* the object to remove the note from.
* @throws IOException
* a portion of the note space is not accessible.
*/
public void remove(AnyObjectId noteOn) throws IOException {
set(noteOn, null);
}
/**
* Write this note map as a tree.
*
* @param inserter
* inserter to use when writing trees to the object database.
* Caller is responsible for flushing the inserter before trying
* to read the objects, or exposing them through a reference.
* @return the top level tree.
* @throws IOException
* a tree could not be written.
*/
public ObjectId writeTree(ObjectInserter inserter) throws IOException {
return root.writeTree(inserter);
}
/** @return the root note bucket */
InMemoryNoteBucket getRoot() {
return root;
}
private void load(ObjectId rootTree) throws MissingObjectException,
IncorrectObjectTypeException, CorruptObjectException, IOException {
AbbreviatedObjectId none = AbbreviatedObjectId.fromString(""); //$NON-NLS-1$
root = NoteParser.parse(none, rootTree, reader);
}
}