tikhomirov@602: /*
tikhomirov@602:  * Copyright (c) 2013 TMate Software Ltd
tikhomirov@602:  *  
tikhomirov@602:  * This program is free software; you can redistribute it and/or modify
tikhomirov@602:  * it under the terms of the GNU General Public License as published by
tikhomirov@602:  * the Free Software Foundation; version 2 of the License.
tikhomirov@602:  *
tikhomirov@602:  * This program is distributed in the hope that it will be useful,
tikhomirov@602:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
tikhomirov@602:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
tikhomirov@602:  * GNU General Public License for more details.
tikhomirov@602:  *
tikhomirov@602:  * For information on how to redistribute this software under
tikhomirov@602:  * the terms of a license other than GNU General Public License
tikhomirov@602:  * contact TMate Software at support@hg4j.com
tikhomirov@602:  */
tikhomirov@602: package org.tmatesoft.hg.internal;
tikhomirov@602: 
tikhomirov@602: import static org.tmatesoft.hg.util.LogFacility.Severity.Error;
tikhomirov@602: 
tikhomirov@602: import java.io.ByteArrayOutputStream;
tikhomirov@602: import java.io.IOException;
tikhomirov@602: import java.util.ArrayList;
tikhomirov@602: import java.util.Collection;
tikhomirov@602: 
tikhomirov@602: import org.tmatesoft.hg.core.SessionContext;
tikhomirov@602: import org.tmatesoft.hg.repo.HgInvalidControlFileException;
tikhomirov@602: import org.tmatesoft.hg.repo.HgInvalidStateException;
tikhomirov@602: import org.tmatesoft.hg.util.LogFacility;
tikhomirov@602: 
tikhomirov@602: /**
tikhomirov@602:  * Container for metadata recorded as part of file revisions
tikhomirov@602:  * 
tikhomirov@602:  * @author Artem Tikhomirov
tikhomirov@602:  * @author TMate Software Ltd.
tikhomirov@602:  */
tikhomirov@602: public final class Metadata {
tikhomirov@602: 	private static class Record {
tikhomirov@602: 		public final int offset;
tikhomirov@602: 		public final MetadataEntry[] entries;
tikhomirov@602: 		
tikhomirov@602: 		public Record(int off, MetadataEntry[] entr) {
tikhomirov@602: 			offset = off;
tikhomirov@602: 			entries = entr;
tikhomirov@602: 		}
tikhomirov@602: 	}
tikhomirov@602: 	// XXX sparse array needed
tikhomirov@602: 	private final IntMap<Metadata.Record> entries = new IntMap<Metadata.Record>(5);
tikhomirov@602: 	
tikhomirov@602: 	private final Metadata.Record NONE = new Record(-1, null); // don't want statics
tikhomirov@602: 
tikhomirov@602: 	private final LogFacility log;
tikhomirov@602: 
tikhomirov@602: 	public Metadata(SessionContext.Source sessionCtx) {
tikhomirov@602: 		log = sessionCtx.getSessionContext().getLog();
tikhomirov@602: 	}
tikhomirov@602: 	
tikhomirov@602: 	// true when there's metadata for given revision
tikhomirov@602: 	public boolean known(int revision) {
tikhomirov@602: 		Metadata.Record i = entries.get(revision);
tikhomirov@602: 		return i != null && NONE != i;
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	// true when revision has been checked for metadata presence.
tikhomirov@602: 	public boolean checked(int revision) {
tikhomirov@602: 		return entries.containsKey(revision);
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	// true when revision has been checked and found not having any metadata
tikhomirov@602: 	public boolean none(int revision) {
tikhomirov@602: 		Metadata.Record i = entries.get(revision);
tikhomirov@602: 		return i == NONE;
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	// mark revision as having no metadata.
tikhomirov@602: 	void recordNone(int revision) {
tikhomirov@602: 		Metadata.Record i = entries.get(revision);
tikhomirov@602: 		if (i == NONE) {
tikhomirov@602: 			return; // already there
tikhomirov@602: 		} 
tikhomirov@602: 		if (i != null) {
tikhomirov@602: 			throw new HgInvalidStateException(String.format("Trying to override Metadata state for revision %d (known offset: %d)", revision, i));
tikhomirov@602: 		}
tikhomirov@602: 		entries.put(revision, NONE);
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	// since this is internal class, callers are supposed to ensure arg correctness (i.e. ask known() before)
tikhomirov@602: 	public int dataOffset(int revision) {
tikhomirov@602: 		return entries.get(revision).offset;
tikhomirov@602: 	}
tikhomirov@602: 	void add(int revision, int dataOffset, Collection<MetadataEntry> e) {
tikhomirov@602: 		assert !entries.containsKey(revision);
tikhomirov@602: 		entries.put(revision, new Record(dataOffset, e.toArray(new MetadataEntry[e.size()])));
tikhomirov@602: 	}
tikhomirov@602: 	
tikhomirov@602: 	/**
tikhomirov@602: 	 * @return <code>true</code> if metadata has been found
tikhomirov@602: 	 */
tikhomirov@602: 	public boolean tryRead(int revisionNumber, DataAccess data) throws IOException, HgInvalidControlFileException {
tikhomirov@602: 		final int daLength = data.length();
tikhomirov@602: 		if (daLength < 4 || data.readByte() != 1 || data.readByte() != 10) {
tikhomirov@602: 			recordNone(revisionNumber);
tikhomirov@602: 			return false;
tikhomirov@602: 		} else {
tikhomirov@602: 			ArrayList<MetadataEntry> _metadata = new ArrayList<MetadataEntry>();
tikhomirov@602: 			int offset = parseMetadata(data, daLength, _metadata);
tikhomirov@602: 			add(revisionNumber, offset, _metadata);
tikhomirov@602: 			return true;
tikhomirov@602: 		}
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	public String find(int revision, String key) {
tikhomirov@602: 		for (MetadataEntry me : entries.get(revision).entries) {
tikhomirov@602: 			if (me.matchKey(key)) {
tikhomirov@602: 				return me.value();
tikhomirov@602: 			}
tikhomirov@602: 		}
tikhomirov@602: 		return null;
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	private int parseMetadata(DataAccess data, final int daLength, ArrayList<MetadataEntry> _metadata) throws IOException, HgInvalidControlFileException {
tikhomirov@602: 		int lastEntryStart = 2;
tikhomirov@602: 		int lastColon = -1;
tikhomirov@602: 		// XXX in fact, need smth like ByteArrayBuilder, similar to StringBuilder,
tikhomirov@602: 		// which can't be used here because we can't convert bytes to chars as we read them
tikhomirov@602: 		// (there might be multi-byte encoding), and we need to collect all bytes before converting to string 
tikhomirov@602: 		ByteArrayOutputStream bos = new ByteArrayOutputStream();
tikhomirov@602: 		String key = null, value = null;
tikhomirov@602: 		boolean byteOne = false;
tikhomirov@602: 		boolean metadataIsComplete = false;
tikhomirov@602: 		for (int i = 2; i < daLength; i++) {
tikhomirov@602: 			byte b = data.readByte();
tikhomirov@602: 			if (b == '\n') {
tikhomirov@602: 				if (byteOne) { // i.e. \n follows 1
tikhomirov@602: 					lastEntryStart = i+1;
tikhomirov@602: 					metadataIsComplete = true;
tikhomirov@602: 					// XXX is it possible to have here incomplete key/value (i.e. if last pair didn't end with \n)
tikhomirov@602: 					// if yes, need to set metadataIsComplete to true in that case as well
tikhomirov@602: 					break;
tikhomirov@602: 				}
tikhomirov@602: 				if (key == null || lastColon == -1 || i <= lastColon) {
tikhomirov@602: 					log.dump(getClass(), Error, "Missing key in file revision metadata at index %d", i);
tikhomirov@602: 				}
tikhomirov@602: 				value = new String(bos.toByteArray()).trim();
tikhomirov@602: 				bos.reset();
tikhomirov@602: 				_metadata.add(new MetadataEntry(key, value));
tikhomirov@602: 				key = value = null;
tikhomirov@602: 				lastColon = -1;
tikhomirov@602: 				lastEntryStart = i+1;
tikhomirov@602: 				continue;
tikhomirov@602: 			} 
tikhomirov@602: 			// byteOne has to be consumed up to this line, if not yet, consume it
tikhomirov@602: 			if (byteOne) {
tikhomirov@602: 				// insert 1 we've read on previous step into the byte builder
tikhomirov@602: 				bos.write(1);
tikhomirov@602: 				byteOne = false;
tikhomirov@602: 				// fall-through to consume current byte
tikhomirov@602: 			}
tikhomirov@602: 			if (b == (int) ':') {
tikhomirov@602: 				assert value == null;
tikhomirov@602: 				key = new String(bos.toByteArray());
tikhomirov@602: 				bos.reset();
tikhomirov@602: 				lastColon = i;
tikhomirov@602: 			} else if (b == 1) {
tikhomirov@602: 				byteOne = true;
tikhomirov@602: 			} else {
tikhomirov@602: 				bos.write(b);
tikhomirov@602: 			}
tikhomirov@602: 		}
tikhomirov@602: 		// data.isEmpty is not reliable, renamed files of size==0 keep only metadata
tikhomirov@602: 		if (!metadataIsComplete) {
tikhomirov@602: 			// XXX perhaps, worth a testcase (empty file, renamed, read or ask ifCopy
tikhomirov@602: 			throw new HgInvalidControlFileException("Metadata is not closed properly", null, null);
tikhomirov@602: 		}
tikhomirov@602: 		return lastEntryStart;
tikhomirov@602: 	}
tikhomirov@602: 
tikhomirov@602: 	/**
tikhomirov@602: 	 * There may be several entries of metadata per single revision, this class captures single entry
tikhomirov@602: 	 */
tikhomirov@602: 	private static class MetadataEntry {
tikhomirov@602: 		private final String entry;
tikhomirov@602: 		private final int valueStart;
tikhomirov@602: 
tikhomirov@602: 		// key may be null
tikhomirov@602: 		/* package-local */MetadataEntry(String key, String value) {
tikhomirov@602: 			if (key == null) {
tikhomirov@602: 				entry = value;
tikhomirov@602: 				valueStart = -1; // not 0 to tell between key == null and key == ""
tikhomirov@602: 			} else {
tikhomirov@602: 				entry = key + value;
tikhomirov@602: 				valueStart = key.length();
tikhomirov@602: 			}
tikhomirov@602: 		}
tikhomirov@602: 
tikhomirov@602: 		/* package-local */boolean matchKey(String key) {
tikhomirov@602: 			return key == null ? valueStart == -1 : key.length() == valueStart && entry.startsWith(key);
tikhomirov@602: 		}
tikhomirov@602: 
tikhomirov@602: //			uncomment once/if needed
tikhomirov@602: //			public String key() {
tikhomirov@602: //				return entry.substring(0, valueStart);
tikhomirov@602: //			}
tikhomirov@602: 
tikhomirov@602: 		public String value() {
tikhomirov@602: 			return valueStart == -1 ? entry : entry.substring(valueStart);
tikhomirov@602: 		}
tikhomirov@602: 	}
tikhomirov@602: }