--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hg4j/src/main/java/org/tmatesoft/hg/repo/HgDataFile.java	Tue May 10 10:52:53 2011 +0200
@@ -0,0 +1,390 @@
+/*
+ * Copyright (c) 2010-2011 TMate Software Ltd
+ *  
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * For information on how to redistribute this software under
+ * the terms of a license other than GNU General Public License
+ * contact TMate Software at support@hg4j.com
+ */
+package org.tmatesoft.hg.repo;
+
+import static org.tmatesoft.hg.repo.HgInternals.wrongLocalRevision;
+import static org.tmatesoft.hg.repo.HgRepository.*;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.TreeMap;
+
+import org.tmatesoft.hg.core.HgDataStreamException;
+import org.tmatesoft.hg.core.HgException;
+import org.tmatesoft.hg.core.Nodeid;
+import org.tmatesoft.hg.internal.DataAccess;
+import org.tmatesoft.hg.internal.FilterByteChannel;
+import org.tmatesoft.hg.internal.RevlogStream;
+import org.tmatesoft.hg.util.ByteChannel;
+import org.tmatesoft.hg.util.CancelledException;
+import org.tmatesoft.hg.util.Path;
+
+
+
+/**
+ * ? name:HgFileNode?
+ *
+ * @author Artem Tikhomirov
+ * @author TMate Software Ltd.
+ */
+public class HgDataFile extends Revlog {
+
+	// absolute from repo root?
+	// slashes, unix-style?
+	// repo location agnostic, just to give info to user, not to access real storage
+	private final Path path;
+	private Metadata metadata; // get initialized on first access to file content.
+	
+	/*package-local*/HgDataFile(HgRepository hgRepo, Path filePath, RevlogStream content) {
+		super(hgRepo, content);
+		path = filePath;
+	}
+
+	/*package-local*/HgDataFile(HgRepository hgRepo, Path filePath) {
+		super(hgRepo);
+		path = filePath;
+	}
+
+	// exists is not the best name possible. now it means no file with such name was ever known to the repo.
+	// it might be confused with files existed before but lately removed. 
+	public boolean exists() {
+		return content != null; // XXX need better impl
+	}
+
+	// human-readable (i.e. "COPYING", not "store/data/_c_o_p_y_i_n_g.i")
+	public Path getPath() {
+		return path; // hgRepo.backresolve(this) -> name? In this case, what about hashed long names?
+	}
+
+	public int length(Nodeid nodeid) {
+		return content.dataLength(getLocalRevision(nodeid));
+	}
+
+	public void workingCopy(ByteChannel sink) throws IOException, CancelledException {
+		throw HgRepository.notImplemented();
+	}
+	
+//	public void content(int revision, ByteChannel sink, boolean applyFilters) throws HgDataStreamException, IOException, CancelledException {
+//		byte[] content = content(revision);
+//		final CancelSupport cancelSupport = CancelSupport.Factory.get(sink);
+//		final ProgressSupport progressSupport = ProgressSupport.Factory.get(sink);
+//		ByteBuffer buf = ByteBuffer.allocate(512);
+//		int left = content.length;
+//		progressSupport.start(left);
+//		int offset = 0;
+//		cancelSupport.checkCancelled();
+//		ByteChannel _sink = applyFilters ? new FilterByteChannel(sink, getRepo().getFiltersFromRepoToWorkingDir(getPath())) : sink;
+//		do {
+//			buf.put(content, offset, Math.min(left, buf.remaining()));
+//			buf.flip();
+//			cancelSupport.checkCancelled();
+//			// XXX I may not rely on returned number of bytes but track change in buf position instead.
+//			int consumed = _sink.write(buf);
+//			buf.compact();
+//			offset += consumed;
+//			left -= consumed;
+//			progressSupport.worked(consumed);
+//		} while (left > 0);
+//		progressSupport.done(); // XXX shall specify whether #done() is invoked always or only if completed successfully.
+//	}
+	
+	/*XXX not sure distinct method contentWithFilters() is the best way to do, perhaps, callers shall add filters themselves?*/
+	public void contentWithFilters(int revision, ByteChannel sink) throws HgDataStreamException, IOException, CancelledException {
+		content(revision, new FilterByteChannel(sink, getRepo().getFiltersFromRepoToWorkingDir(getPath())));
+	}
+
+	// for data files need to check heading of the file content for possible metadata
+	// @see http://mercurial.selenic.com/wiki/FileFormats#data.2BAC8-
+	public void content(int revision, ByteChannel sink) throws HgDataStreamException, IOException, CancelledException {
+		if (revision == TIP) {
+			revision = getLastRevision();
+		}
+		if (revision == WORKING_COPY) {
+			workingCopy(sink);
+			return;
+		}
+		if (wrongLocalRevision(revision) || revision == BAD_REVISION) {
+			throw new IllegalArgumentException(String.valueOf(revision));
+		}
+		if (sink == null) {
+			throw new IllegalArgumentException();
+		}
+		if (metadata == null) {
+			metadata = new Metadata();
+		}
+		ContentPipe insp;
+		if (metadata.none(revision)) {
+			insp = new ContentPipe(sink, 0);
+		} else if (metadata.known(revision)) {
+			insp = new ContentPipe(sink, metadata.dataOffset(revision));
+		} else {
+			// do not know if there's metadata
+			insp = new MetadataContentPipe(sink, metadata);
+		}
+		insp.checkCancelled();
+		super.content.iterate(revision, revision, true, insp);
+		try {
+			insp.checkFailed();
+		} catch (HgDataStreamException ex) {
+			throw ex;
+		} catch (HgException ex) {
+			// shall not happen, unless we changed ContentPipe or its subclass
+			throw new HgDataStreamException(ex.getClass().getName(), ex);
+		}
+	}
+	
+	public void history(HgChangelog.Inspector inspector) {
+		history(0, getLastRevision(), inspector);
+	}
+
+	public void history(int start, int end, HgChangelog.Inspector inspector) {
+		if (!exists()) {
+			throw new IllegalStateException("Can't get history of invalid repository file node"); 
+		}
+		final int last = getLastRevision();
+		if (start < 0 || start > last) {
+			throw new IllegalArgumentException();
+		}
+		if (end == TIP) {
+			end = last;
+		} else if (end < start || end > last) {
+			throw new IllegalArgumentException();
+		}
+		final int[] commitRevisions = new int[end - start + 1];
+		RevlogStream.Inspector insp = new RevlogStream.Inspector() {
+			int count = 0;
+			
+			public void next(int revisionNumber, int actualLen, int baseRevision, int linkRevision, int parent1Revision, int parent2Revision, byte[] nodeid, DataAccess data) {
+				commitRevisions[count++] = linkRevision;
+			}
+		};
+		content.iterate(start, end, false, insp);
+		getRepo().getChangelog().range(inspector, commitRevisions);
+	}
+	
+	// for a given local revision of the file, find out local revision in the changelog
+	public int getChangesetLocalRevision(int revision) {
+		return content.linkRevision(revision);
+	}
+
+	public Nodeid getChangesetRevision(Nodeid nid) {
+		int changelogRevision = getChangesetLocalRevision(getLocalRevision(nid));
+		return getRepo().getChangelog().getRevision(changelogRevision);
+	}
+
+	public boolean isCopy() throws HgDataStreamException {
+		if (metadata == null || !metadata.checked(0)) {
+			// content() always initializes metadata.
+			// FIXME this is expensive way to find out metadata, distinct RevlogStream.Iterator would be better.
+			// Alternatively, may parameterize MetadataContentPipe to do prepare only.
+			// For reference, when throwing CancelledException, hg status -A --rev 3:80 takes 70 ms
+			// however, if we just consume buffer instead (buffer.position(buffer.limit()), same command takes ~320ms
+			// (compared to command-line counterpart of 190ms)
+			try {
+				content(0, new ByteChannel() { // No-op channel
+					public int write(ByteBuffer buffer) throws IOException, CancelledException {
+						// pretend we consumed whole buffer
+//						int rv = buffer.remaining();
+//						buffer.position(buffer.limit());
+//						return rv;
+						throw new CancelledException();
+					}
+				});
+			} catch (CancelledException ex) {
+				// it's ok, we did that
+			} catch (Exception ex) {
+				throw new HgDataStreamException("Can't initialize metadata", ex);
+			}
+		}
+		if (!metadata.known(0)) {
+			return false;
+		}
+		return metadata.find(0, "copy") != null;
+	}
+
+	public Path getCopySourceName() throws HgDataStreamException {
+		if (isCopy()) {
+			return Path.create(metadata.find(0, "copy"));
+		}
+		throw new UnsupportedOperationException(); // XXX REVISIT, think over if Exception is good (clients would check isCopy() anyway, perhaps null is sufficient?)
+	}
+	
+	public Nodeid getCopySourceRevision() throws HgDataStreamException {
+		if (isCopy()) {
+			return Nodeid.fromAscii(metadata.find(0, "copyrev")); // XXX reuse/cache Nodeid
+		}
+		throw new UnsupportedOperationException();
+	}
+	
+	@Override
+	public String toString() {
+		StringBuilder sb = new StringBuilder(getClass().getSimpleName());
+		sb.append('(');
+		sb.append(getPath());
+		sb.append(')');
+		return sb.toString();
+	}
+
+	private static final class MetadataEntry {
+		private final String entry;
+		private final int valueStart;
+		/*package-local*/MetadataEntry(String key, String value) {
+			entry = key + value;
+			valueStart = key.length();
+		}
+		/*package-local*/boolean matchKey(String key) {
+			return key.length() == valueStart && entry.startsWith(key);
+		}
+//		uncomment once/if needed
+//		public String key() {
+//			return entry.substring(0, valueStart);
+//		}
+		public String value() {
+			return entry.substring(valueStart);
+		}
+	}
+
+	private static class Metadata {
+		// XXX sparse array needed
+		private final TreeMap<Integer, Integer> offsets = new TreeMap<Integer, Integer>();
+		private final TreeMap<Integer, MetadataEntry[]> entries = new TreeMap<Integer, MetadataEntry[]>();
+		
+		private final Integer NONE = new Integer(-1); // do not duplicate -1 integers at least within single file (don't want statics)
+
+		// true when there's metadata for given revision
+		boolean known(int revision) {
+			Integer i = offsets.get(revision);
+			return i != null && NONE != i;
+		}
+
+		// true when revision has been checked for metadata presence.
+		public boolean checked(int revision) {
+			return offsets.containsKey(revision);
+		}
+
+		// true when revision has been checked and found not having any metadata
+		boolean none(int revision) {
+			Integer i = offsets.get(revision);
+			return i == NONE;
+		}
+
+		// mark revision as having no metadata.
+		void recordNone(int revision) {
+			Integer i = offsets.get(revision);
+			if (i == NONE) {
+				return; // already there
+			} 
+			if (i != null) {
+				throw new IllegalStateException(String.format("Trying to override Metadata state for revision %d (known offset: %d)", revision, i));
+			}
+			offsets.put(revision, NONE);
+		}
+
+		// since this is internal class, callers are supposed to ensure arg correctness (i.e. ask known() before)
+		int dataOffset(int revision) {
+			return offsets.get(revision);
+		}
+		void add(int revision, int dataOffset, Collection<MetadataEntry> e) {
+			assert !offsets.containsKey(revision);
+			offsets.put(revision, dataOffset);
+			entries.put(revision, e.toArray(new MetadataEntry[e.size()]));
+		}
+		String find(int revision, String key) {
+			for (MetadataEntry me : entries.get(revision)) {
+				if (me.matchKey(key)) {
+					return me.value();
+				}
+			}
+			return null;
+		}
+	}
+
+	private static class MetadataContentPipe extends ContentPipe {
+
+		private final Metadata metadata;
+
+		public MetadataContentPipe(ByteChannel sink, Metadata _metadata) {
+			super(sink, 0);
+			metadata = _metadata;
+		}
+
+		@Override
+		protected void prepare(int revisionNumber, DataAccess da) throws HgException, IOException {
+			final int daLength = da.length();
+			if (daLength < 4 || da.readByte() != 1 || da.readByte() != 10) {
+				metadata.recordNone(revisionNumber);
+				da.reset();
+				return;
+			}
+			int lastEntryStart = 2;
+			int lastColon = -1;
+			ArrayList<MetadataEntry> _metadata = new ArrayList<MetadataEntry>();
+			// XXX in fact, need smth like ByteArrayBuilder, similar to StringBuilder,
+			// which can't be used here because we can't convert bytes to chars as we read them
+			// (there might be multi-byte encoding), and we need to collect all bytes before converting to string 
+			ByteArrayOutputStream bos = new ByteArrayOutputStream();
+			String key = null, value = null;
+			boolean byteOne = false;
+			for (int i = 2; i < daLength; i++) {
+				byte b = da.readByte();
+				if (b == '\n') {
+					if (byteOne) { // i.e. \n follows 1
+						lastEntryStart = i+1;
+						// XXX is it possible to have here incomplete key/value (i.e. if last pair didn't end with \n)
+						break;
+					}
+					if (key == null || lastColon == -1 || i <= lastColon) {
+						throw new IllegalStateException(); // FIXME log instead and record null key in the metadata. Ex just to fail fast during dev
+					}
+					value = new String(bos.toByteArray()).trim();
+					bos.reset();
+					_metadata.add(new MetadataEntry(key, value));
+					key = value = null;
+					lastColon = -1;
+					lastEntryStart = i+1;
+					continue;
+				} 
+				// byteOne has to be consumed up to this line, if not jet, consume it
+				if (byteOne) {
+					// insert 1 we've read on previous step into the byte builder
+					bos.write(1);
+					// fall-through to consume current byte
+					byteOne = false;
+				}
+				if (b == (int) ':') {
+					assert value == null;
+					key = new String(bos.toByteArray());
+					bos.reset();
+					lastColon = i;
+				} else if (b == 1) {
+					byteOne = true;
+				} else {
+					bos.write(b);
+				}
+			}
+			_metadata.trimToSize();
+			metadata.add(revisionNumber, lastEntryStart, _metadata);
+			if (da.isEmpty() || !byteOne) {
+				throw new HgDataStreamException(String.format("Metadata for revision %d is not closed properly", revisionNumber), null);
+			}
+			// da is in prepared state (i.e. we consumed all bytes up to metadata end).
+		}
+	}
+}