Add an object encapsulating the state of a PackWriter

Exposes essentially the same state machine to the programmer as is
exposed to the client via a ProgressMonitor, using a wrapper around
beginTask()/endTask().

Change-Id: Ic3622b4acea65d2b9b3551c668806981fa7293e3

org.eclipse.jgit/resources/org/eclipse/jgit/JGitText.properties

@@ -215,6 +215,7 @@ hunkDisconnectedFromFile=Hunk disconnected from file
 hunkHeaderDoesNotMatchBodyLineCountOf=Hunk header {0} does not match body line count of {1}
 illegalArgumentNotA=Not {0}
 illegalCombinationOfArguments=The combination of arguments {0} and {1} is not allowed
+illegalPackingPhase=Illegal packing phase {0}
 illegalStateExists=exists {0}
 improperlyPaddedBase64Input=Improperly padded Base64 input.
 inMemoryBufferLimitExceeded=In-memory buffer limit exceeded

org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java

@@ -275,6 +275,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String hunkHeaderDoesNotMatchBodyLineCountOf;
 	/***/ public String illegalArgumentNotA;
 	/***/ public String illegalCombinationOfArguments;
+	/***/ public String illegalPackingPhase;
 	/***/ public String illegalStateExists;
 	/***/ public String improperlyPaddedBase64Input;
 	/***/ public String inMemoryBufferLimitExceeded;

org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/PackWriter.java

@@ -174,6 +174,8 @@ public class PackWriter {
 
 	private final Statistics stats;
 
+	private final MutableState state;
+
 	private Statistics.ObjectType typeStats;
 
 	private List<ObjectToPack> sortedByName;
@@ -266,6 +268,7 @@ public class PackWriter {
 		reuseDeltas = config.isReuseDeltas();
 		reuseValidate = true; // be paranoid by default
 		stats = new Statistics();
+		state = new MutableState();
 	}
 
 	/**
@@ -744,6 +747,37 @@ public class PackWriter {
 		return sortedByName;
 	}
 
+	private void beginPhase(PackingPhase phase, ProgressMonitor monitor,
+			int cnt) {
+		state.phase = phase;
+		String task;
+		switch (phase) {
+		case COUNTING:
+			task = JGitText.get().countingObjects;
+			break;
+		case GETTING_SIZES:
+			task = JGitText.get().searchForSizes;
+			break;
+		case FINDING_SOURCES:
+			task = JGitText.get().searchForReuse;
+			break;
+		case COMPRESSING:
+			task = JGitText.get().compressingObjects;
+			break;
+		case WRITING:
+			task = JGitText.get().writingObjects;
+			break;
+		default:
+			throw new IllegalArgumentException(
+					MessageFormat.format(JGitText.get().illegalPackingPhase, phase));
+		}
+		monitor.beginTask(task, cnt);
+	}
+
+	private void endPhase(ProgressMonitor monitor) {
+		monitor.endTask();
+	}
+
 	/**
 	 * Write the prepared pack to the supplied stream.
 	 * <p>
@@ -803,7 +837,7 @@ public class PackWriter {
 
 		long objCnt = getObjectCount();
 		stats.totalObjects = objCnt;
-		writeMonitor.beginTask(JGitText.get().writingObjects, (int) objCnt);
+		beginPhase(PackingPhase.WRITING, writeMonitor, (int) objCnt);
 		long writeStart = System.currentTimeMillis();
 
 		out.writeFileHeader(PACK_VERSION_GENERATED, objCnt);
@@ -843,7 +877,7 @@ public class PackWriter {
 		}
 
 		reader.release();
-		writeMonitor.endTask();
+		endPhase(writeMonitor);
 	}
 
 	/**
@@ -855,6 +889,11 @@ public class PackWriter {
 		return stats;
 	}
 
+	/** @return snapshot of the current state of this PackWriter. */
+	public State getState() {
+		return state.snapshot();
+	}
+
 	/** Release all resources used by this writer. */
 	public void release() {
 		reader.release();
@@ -872,7 +911,7 @@ public class PackWriter {
 		cnt += objectsLists[Constants.OBJ_TAG].size();
 
 		long start = System.currentTimeMillis();
-		monitor.beginTask(JGitText.get().searchForReuse, cnt);
+		beginPhase(PackingPhase.FINDING_SOURCES, monitor, cnt);
 
 		if (cnt <= 4096) {
 			// For small object counts, do everything as one list.
@@ -897,7 +936,7 @@ public class PackWriter {
 			searchForReuse(monitor, objectsLists[Constants.OBJ_TAG]);
 		}
 
-		monitor.endTask();
+		endPhase(monitor);
 		stats.timeSearchingForReuse = System.currentTimeMillis() - start;
 	}
 
@@ -944,7 +983,7 @@ public class PackWriter {
 		// abort with an exception if we actually had to have it.
 		//
 		final long sizingStart = System.currentTimeMillis();
-		monitor.beginTask(JGitText.get().searchForSizes, cnt);
+		beginPhase(PackingPhase.GETTING_SIZES, monitor, cnt);
 		AsyncObjectSizeQueue<ObjectToPack> sizeQueue = reader.getObjectSize(
 				Arrays.<ObjectToPack> asList(list).subList(0, cnt), false);
 		try {
@@ -989,7 +1028,7 @@ public class PackWriter {
 		} finally {
 			sizeQueue.release();
 		}
-		monitor.endTask();
+		endPhase(monitor);
 		stats.timeSearchingForSizes = System.currentTimeMillis() - sizingStart;
 
 		// Sort the objects by path hash so like files are near each other,
@@ -1035,9 +1074,9 @@ public class PackWriter {
 			return;
 
 		final long searchStart = System.currentTimeMillis();
-		monitor.beginTask(JGitText.get().compressingObjects, nonEdgeCnt);
+		beginPhase(PackingPhase.COMPRESSING, monitor, nonEdgeCnt);
 		searchForDeltas(monitor, list, cnt);
-		monitor.endTask();
+		endPhase(monitor);
 		stats.deltaSearchNonEdgeObjects = nonEdgeCnt;
 		stats.timeCompressing = System.currentTimeMillis() - searchStart;
 
@@ -1400,8 +1439,7 @@ public class PackWriter {
 			throws MissingObjectException, IOException,
 			IncorrectObjectTypeException {
 		final long countingStart = System.currentTimeMillis();
-		countingMonitor.beginTask(JGitText.get().countingObjects,
-				ProgressMonitor.UNKNOWN);
+		beginPhase(PackingPhase.COUNTING, countingMonitor, ProgressMonitor.UNKNOWN);
 
 		if (have == null)
 			have = Collections.emptySet();
@@ -1447,7 +1485,7 @@ public class PackWriter {
 					cachedPacks.addAll(shortCircuit);
 					for (CachedPack pack : shortCircuit)
 						countingMonitor.update((int) pack.getObjectCount());
-					countingMonitor.endTask();
+					endPhase(countingMonitor);
 					stats.timeCounting = System.currentTimeMillis() - countingStart;
 					return;
 				}
@@ -1537,8 +1575,8 @@ public class PackWriter {
 							wantObjs, haveObjs, pack);
 					commits = new BlockList<RevCommit>();
 
-					countingMonitor.endTask();
-					countingMonitor.beginTask(JGitText.get().countingObjects,
+					endPhase(countingMonitor);
+					beginPhase(PackingPhase.COUNTING, countingMonitor,
 							ProgressMonitor.UNKNOWN);
 					continue;
 				}
@@ -1625,7 +1663,7 @@ public class PackWriter {
 
 		for (CachedPack pack : cachedPacks)
 			countingMonitor.update((int) pack.getObjectCount());
-		countingMonitor.endTask();
+		endPhase(countingMonitor);
 		stats.timeCounting = System.currentTimeMillis() - countingStart;
 	}
 
@@ -2099,4 +2137,58 @@ public class PackWriter {
 					reusedObjects, reusedDeltas);
 		}
 	}
+
+	private class MutableState {
+		private volatile PackingPhase phase;
+
+		MutableState() {
+			phase = PackingPhase.COUNTING;
+		}
+
+		State snapshot() {
+			return new State(phase);
+		}
+	}
+
+	/** Possible states that a PackWriter can be in. */
+	public static enum PackingPhase {
+		/** Counting objects phase. */
+		COUNTING,
+
+		/** Getting sizes phase. */
+		GETTING_SIZES,
+
+		/** Finding sources phase. */
+		FINDING_SOURCES,
+
+		/** Compressing objects phase. */
+		COMPRESSING,
+
+		/** Writing objects phase. */
+		WRITING;
+	}
+
+	/** Summary of the current state of a PackWriter. */
+	public class State {
+		private final PackingPhase phase;
+
+		State(PackingPhase phase) {
+			this.phase = phase;
+		}
+
+		/** @return the PackConfig used to build the writer. */
+		public PackConfig getConfig() {
+			return config;
+		}
+
+		/** @return the current phase of the writer. */
+		public PackingPhase getPhase() {
+			return phase;
+		}
+
+		@Override
+		public String toString() {
+			return "PackWriter.State[" + phase + "]";
+		}
+	}
 }