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1   /*
2    * Copyright (C) 2008-2010, Google Inc.
3    * Copyright (C) 2008, Marek Zawirski <marek.zawirski@gmail.com>
4    * and other copyright owners as documented in the project's IP log.
5    *
6    * This program and the accompanying materials are made available
7    * under the terms of the Eclipse Distribution License v1.0 which
8    * accompanies this distribution, is reproduced below, and is
9    * available at http://www.eclipse.org/org/documents/edl-v10.php
10   *
11   * All rights reserved.
12   *
13   * Redistribution and use in source and binary forms, with or
14   * without modification, are permitted provided that the following
15   * conditions are met:
16   *
17   * - Redistributions of source code must retain the above copyright
18   *   notice, this list of conditions and the following disclaimer.
19   *
20   * - Redistributions in binary form must reproduce the above
21   *   copyright notice, this list of conditions and the following
22   *   disclaimer in the documentation and/or other materials provided
23   *   with the distribution.
24   *
25   * - Neither the name of the Eclipse Foundation, Inc. nor the
26   *   names of its contributors may be used to endorse or promote
27   *   products derived from this software without specific prior
28   *   written permission.
29   *
30   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
31   * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
32   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
33   * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
34   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
35   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
36   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
37   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
38   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
39   * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
40   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
41   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
42   * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
43   */
44  
45  package org.eclipse.jgit.storage.pack;
46  
47  import java.util.concurrent.Executor;
48  import java.util.zip.Deflater;
49  
50  import org.eclipse.jgit.internal.storage.file.PackIndexWriter;
51  import org.eclipse.jgit.lib.Config;
52  import org.eclipse.jgit.lib.Repository;
53  
54  /**
55   * Configuration used by a pack writer when constructing the stream.
56   *
57   * A configuration may be modified once created, but should not be modified
58   * while it is being used by a PackWriter. If a configuration is not modified it
59   * is safe to share the same configuration instance between multiple concurrent
60   * threads executing different PackWriters.
61   */
62  public class PackConfig {
63  	/**
64  	 * Default value of deltas reuse option: {@value}
65  	 *
66  	 * @see #setReuseDeltas(boolean)
67  	 */
68  	public static final boolean DEFAULT_REUSE_DELTAS = true;
69  
70  	/**
71  	 * Default value of objects reuse option: {@value}
72  	 *
73  	 * @see #setReuseObjects(boolean)
74  	 */
75  	public static final boolean DEFAULT_REUSE_OBJECTS = true;
76  
77  	/**
78  	 * Default value of keep old packs option: {@value}
79  	 * @see #setPreserveOldPacks(boolean)
80  	 * @since 4.7
81  	 */
82  	public static final boolean DEFAULT_PRESERVE_OLD_PACKS = false;
83  
84  	/**
85  	 * Default value of prune old packs option: {@value}
86  	 * @see #setPrunePreserved(boolean)
87  	 * @since 4.7
88  	 */
89  	public static final boolean DEFAULT_PRUNE_PRESERVED = false;
90  
91  	/**
92  	 * Default value of delta compress option: {@value}
93  	 *
94  	 * @see #setDeltaCompress(boolean)
95  	 */
96  	public static final boolean DEFAULT_DELTA_COMPRESS = true;
97  
98  	/**
99  	 * Default value of delta base as offset option: {@value}
100 	 *
101 	 * @see #setDeltaBaseAsOffset(boolean)
102 	 */
103 	public static final boolean DEFAULT_DELTA_BASE_AS_OFFSET = false;
104 
105 	/**
106 	 * Default value of maximum delta chain depth: {@value}
107 	 *
108 	 * @see #setMaxDeltaDepth(int)
109 	 */
110 	public static final int DEFAULT_MAX_DELTA_DEPTH = 50;
111 
112 	/**
113 	 * Default window size during packing: {@value}
114 	 *
115 	 * @see #setDeltaSearchWindowSize(int)
116 	 */
117 	public static final int DEFAULT_DELTA_SEARCH_WINDOW_SIZE = 10;
118 
119 	/**
120 	 * Default big file threshold: {@value}
121 	 *
122 	 * @see #setBigFileThreshold(int)
123 	 */
124 	public static final int DEFAULT_BIG_FILE_THRESHOLD = 50 * 1024 * 1024;
125 
126 	/**
127 	 * Default delta cache size: {@value}
128 	 *
129 	 * @see #setDeltaCacheSize(long)
130 	 */
131 	public static final long DEFAULT_DELTA_CACHE_SIZE = 50 * 1024 * 1024;
132 
133 	/**
134 	 * Default delta cache limit: {@value}
135 	 *
136 	 * @see #setDeltaCacheLimit(int)
137 	 */
138 	public static final int DEFAULT_DELTA_CACHE_LIMIT = 100;
139 
140 	/**
141 	 * Default index version: {@value}
142 	 *
143 	 * @see #setIndexVersion(int)
144 	 */
145 	public static final int DEFAULT_INDEX_VERSION = 2;
146 
147 	/**
148 	 * Default value of the build bitmaps option: {@value}
149 	 *
150 	 * @see #setBuildBitmaps(boolean)
151 	 * @since 3.0
152 	 */
153 	public static final boolean DEFAULT_BUILD_BITMAPS = true;
154 
155 	/**
156 	 * Default count of most recent commits to select for bitmaps. Only applies
157 	 * when bitmaps are enabled: {@value}
158 	 *
159 	 * @see #setBitmapContiguousCommitCount(int)
160 	 * @since 4.2
161 	 */
162 	public static final int DEFAULT_BITMAP_CONTIGUOUS_COMMIT_COUNT = 100;
163 
164 	/**
165 	 * Count at which the span between selected commits changes from
166 	 * "bitmapRecentCommitSpan" to "bitmapDistantCommitSpan". Only applies when
167 	 * bitmaps are enabled: {@value}
168 	 *
169 	 * @see #setBitmapRecentCommitCount(int)
170 	 * @since 4.2
171 	 */
172 	public static final int DEFAULT_BITMAP_RECENT_COMMIT_COUNT = 20000;
173 
174 	/**
175 	 * Default spacing between commits in recent history when selecting commits
176 	 * for bitmaps. Only applies when bitmaps are enabled: {@value}
177 	 *
178 	 * @see #setBitmapRecentCommitSpan(int)
179 	 * @since 4.2
180 	 */
181 	public static final int DEFAULT_BITMAP_RECENT_COMMIT_SPAN = 100;
182 
183 	/**
184 	 * Default spacing between commits in distant history when selecting commits
185 	 * for bitmaps. Only applies when bitmaps are enabled: {@value}
186 	 *
187 	 * @see #setBitmapDistantCommitSpan(int)
188 	 * @since 4.2
189 	 */
190 	public static final int DEFAULT_BITMAP_DISTANT_COMMIT_SPAN = 5000;
191 
192 	/**
193 	 * Default count of branches required to activate inactive branch commit
194 	 * selection. If the number of branches is less than this then bitmaps for
195 	 * the entire commit history of all branches will be created, otherwise
196 	 * branches marked as "inactive" will have coverage for only partial
197 	 * history: {@value}
198 	 *
199 	 * @see #setBitmapExcessiveBranchCount(int)
200 	 * @since 4.2
201 	 */
202 	public static final int DEFAULT_BITMAP_EXCESSIVE_BRANCH_COUNT = 100;
203 
204 	/**
205 	 * Default age at which a branch is considered inactive. Age is taken as the
206 	 * number of days ago that the most recent commit was made to a branch. Only
207 	 * affects bitmap processing if bitmaps are enabled and the
208 	 * "excessive branch count" has been exceeded: {@value}
209 	 *
210 	 * @see #setBitmapInactiveBranchAgeInDays(int)
211 	 * @since 4.2
212 	 */
213 	public static final int DEFAULT_BITMAP_INACTIVE_BRANCH_AGE_IN_DAYS = 90;
214 
215 	private int compressionLevel = Deflater.DEFAULT_COMPRESSION;
216 
217 	private boolean reuseDeltas = DEFAULT_REUSE_DELTAS;
218 
219 	private boolean reuseObjects = DEFAULT_REUSE_OBJECTS;
220 
221 	private boolean preserveOldPacks = DEFAULT_PRESERVE_OLD_PACKS;
222 
223 	private boolean prunePreserved = DEFAULT_PRUNE_PRESERVED;
224 
225 	private boolean deltaBaseAsOffset = DEFAULT_DELTA_BASE_AS_OFFSET;
226 
227 	private boolean deltaCompress = DEFAULT_DELTA_COMPRESS;
228 
229 	private int maxDeltaDepth = DEFAULT_MAX_DELTA_DEPTH;
230 
231 	private int deltaSearchWindowSize = DEFAULT_DELTA_SEARCH_WINDOW_SIZE;
232 
233 	private long deltaSearchMemoryLimit;
234 
235 	private long deltaCacheSize = DEFAULT_DELTA_CACHE_SIZE;
236 
237 	private int deltaCacheLimit = DEFAULT_DELTA_CACHE_LIMIT;
238 
239 	private int bigFileThreshold = DEFAULT_BIG_FILE_THRESHOLD;
240 
241 	private int threads;
242 
243 	private Executor executor;
244 
245 	private int indexVersion = DEFAULT_INDEX_VERSION;
246 
247 	private boolean buildBitmaps = DEFAULT_BUILD_BITMAPS;
248 
249 	private int bitmapContiguousCommitCount = DEFAULT_BITMAP_CONTIGUOUS_COMMIT_COUNT;
250 
251 	private int bitmapRecentCommitCount = DEFAULT_BITMAP_RECENT_COMMIT_COUNT;
252 
253 	private int bitmapRecentCommitSpan = DEFAULT_BITMAP_RECENT_COMMIT_SPAN;
254 
255 	private int bitmapDistantCommitSpan = DEFAULT_BITMAP_DISTANT_COMMIT_SPAN;
256 
257 	private int bitmapExcessiveBranchCount = DEFAULT_BITMAP_EXCESSIVE_BRANCH_COUNT;
258 
259 	private int bitmapInactiveBranchAgeInDays = DEFAULT_BITMAP_INACTIVE_BRANCH_AGE_IN_DAYS;
260 
261 	private boolean cutDeltaChains;
262 
263 	private boolean singlePack;
264 
265 	/**
266 	 * Create a default configuration.
267 	 */
268 	public PackConfig() {
269 		// Fields are initialized to defaults.
270 	}
271 
272 	/**
273 	 * Create a configuration honoring the repository's settings.
274 	 *
275 	 * @param db
276 	 *            the repository to read settings from. The repository is not
277 	 *            retained by the new configuration, instead its settings are
278 	 *            copied during the constructor.
279 	 */
280 	public PackConfig(Repository db) {
281 		fromConfig(db.getConfig());
282 	}
283 
284 	/**
285 	 * Create a configuration honoring settings in a
286 	 * {@link org.eclipse.jgit.lib.Config}.
287 	 *
288 	 * @param cfg
289 	 *            the source to read settings from. The source is not retained
290 	 *            by the new configuration, instead its settings are copied
291 	 *            during the constructor.
292 	 */
293 	public PackConfig(Config cfg) {
294 		fromConfig(cfg);
295 	}
296 
297 	/**
298 	 * Copy an existing configuration to a new instance.
299 	 *
300 	 * @param cfg
301 	 *            the source configuration to copy from.
302 	 */
303 	public PackConfig(PackConfig cfg) {
304 		this.compressionLevel = cfg.compressionLevel;
305 		this.reuseDeltas = cfg.reuseDeltas;
306 		this.reuseObjects = cfg.reuseObjects;
307 		this.preserveOldPacks = cfg.preserveOldPacks;
308 		this.prunePreserved = cfg.prunePreserved;
309 		this.deltaBaseAsOffset = cfg.deltaBaseAsOffset;
310 		this.deltaCompress = cfg.deltaCompress;
311 		this.maxDeltaDepth = cfg.maxDeltaDepth;
312 		this.deltaSearchWindowSize = cfg.deltaSearchWindowSize;
313 		this.deltaSearchMemoryLimit = cfg.deltaSearchMemoryLimit;
314 		this.deltaCacheSize = cfg.deltaCacheSize;
315 		this.deltaCacheLimit = cfg.deltaCacheLimit;
316 		this.bigFileThreshold = cfg.bigFileThreshold;
317 		this.threads = cfg.threads;
318 		this.executor = cfg.executor;
319 		this.indexVersion = cfg.indexVersion;
320 		this.buildBitmaps = cfg.buildBitmaps;
321 		this.bitmapContiguousCommitCount = cfg.bitmapContiguousCommitCount;
322 		this.bitmapRecentCommitCount = cfg.bitmapRecentCommitCount;
323 		this.bitmapRecentCommitSpan = cfg.bitmapRecentCommitSpan;
324 		this.bitmapDistantCommitSpan = cfg.bitmapDistantCommitSpan;
325 		this.bitmapExcessiveBranchCount = cfg.bitmapExcessiveBranchCount;
326 		this.bitmapInactiveBranchAgeInDays = cfg.bitmapInactiveBranchAgeInDays;
327 		this.cutDeltaChains = cfg.cutDeltaChains;
328 		this.singlePack = cfg.singlePack;
329 	}
330 
331 	/**
332 	 * Check whether to reuse deltas existing in repository.
333 	 *
334 	 * Default setting: {@value #DEFAULT_REUSE_DELTAS}
335 	 *
336 	 * @return true if object is configured to reuse deltas; false otherwise.
337 	 */
338 	public boolean isReuseDeltas() {
339 		return reuseDeltas;
340 	}
341 
342 	/**
343 	 * Set reuse deltas configuration option for the writer.
344 	 *
345 	 * When enabled, writer will search for delta representation of object in
346 	 * repository and use it if possible. Normally, only deltas with base to
347 	 * another object existing in set of objects to pack will be used. The
348 	 * exception however is thin-packs where the base object may exist on the
349 	 * other side.
350 	 *
351 	 * When raw delta data is directly copied from a pack file, its checksum is
352 	 * computed to verify the data is not corrupt.
353 	 *
354 	 * Default setting: {@value #DEFAULT_REUSE_DELTAS}
355 	 *
356 	 * @param reuseDeltas
357 	 *            boolean indicating whether or not try to reuse deltas.
358 	 */
359 	public void setReuseDeltas(boolean reuseDeltas) {
360 		this.reuseDeltas = reuseDeltas;
361 	}
362 
363 	/**
364 	 * Checks whether to reuse existing objects representation in repository.
365 	 *
366 	 * Default setting: {@value #DEFAULT_REUSE_OBJECTS}
367 	 *
368 	 * @return true if writer is configured to reuse objects representation from
369 	 *         pack; false otherwise.
370 	 */
371 	public boolean isReuseObjects() {
372 		return reuseObjects;
373 	}
374 
375 	/**
376 	 * Set reuse objects configuration option for the writer.
377 	 *
378 	 * If enabled, writer searches for compressed representation in a pack file.
379 	 * If possible, compressed data is directly copied from such a pack file.
380 	 * Data checksum is verified.
381 	 *
382 	 * Default setting: {@value #DEFAULT_REUSE_OBJECTS}
383 	 *
384 	 * @param reuseObjects
385 	 *            boolean indicating whether or not writer should reuse existing
386 	 *            objects representation.
387 	 */
388 	public void setReuseObjects(boolean reuseObjects) {
389 		this.reuseObjects = reuseObjects;
390 	}
391 
392 	/**
393 	 * Checks whether to preserve old packs in a preserved directory
394 	 *
395 	 * Default setting: {@value #DEFAULT_PRESERVE_OLD_PACKS}
396 	 *
397 	 * @return true if repacking will preserve old pack files.
398 	 * @since 4.7
399 	 */
400 	public boolean isPreserveOldPacks() {
401 		return preserveOldPacks;
402 	}
403 
404 	/**
405 	 * Set preserve old packs configuration option for repacking.
406 	 *
407 	 * If enabled, old pack files are moved into a preserved subdirectory instead
408 	 * of being deleted
409 	 *
410 	 * Default setting: {@value #DEFAULT_PRESERVE_OLD_PACKS}
411 	 *
412 	 * @param preserveOldPacks
413 	 *            boolean indicating whether or not preserve old pack files
414 	 * @since 4.7
415 	 */
416 	public void setPreserveOldPacks(boolean preserveOldPacks) {
417 		this.preserveOldPacks = preserveOldPacks;
418 	}
419 
420 	/**
421 	 * Checks whether to remove preserved pack files in a preserved directory
422 	 *
423 	 * Default setting: {@value #DEFAULT_PRUNE_PRESERVED}
424 	 *
425 	 * @return true if repacking will remove preserved pack files.
426 	 * @since 4.7
427 	 */
428 	public boolean isPrunePreserved() {
429 		return prunePreserved;
430 	}
431 
432 	/**
433 	 * Set prune preserved configuration option for repacking.
434 	 *
435 	 * If enabled, preserved pack files are removed from a preserved subdirectory
436 	 *
437 	 * Default setting: {@value #DEFAULT_PRESERVE_OLD_PACKS}
438 	 *
439 	 * @param prunePreserved
440 	 *            boolean indicating whether or not preserve old pack files
441 	 * @since 4.7
442 	 */
443 	public void setPrunePreserved(boolean prunePreserved) {
444 		this.prunePreserved = prunePreserved;
445 	}
446 
447 	/**
448 	 * True if writer can use offsets to point to a delta base.
449 	 *
450 	 * If true the writer may choose to use an offset to point to a delta base
451 	 * in the same pack, this is a newer style of reference that saves space.
452 	 * False if the writer has to use the older (and more compatible style) of
453 	 * storing the full ObjectId of the delta base.
454 	 *
455 	 * Default setting: {@value #DEFAULT_DELTA_BASE_AS_OFFSET}
456 	 *
457 	 * @return true if delta base is stored as an offset; false if it is stored
458 	 *         as an ObjectId.
459 	 */
460 	public boolean isDeltaBaseAsOffset() {
461 		return deltaBaseAsOffset;
462 	}
463 
464 	/**
465 	 * Set writer delta base format.
466 	 *
467 	 * Delta base can be written as an offset in a pack file (new approach
468 	 * reducing file size) or as an object id (legacy approach, compatible with
469 	 * old readers).
470 	 *
471 	 * Default setting: {@value #DEFAULT_DELTA_BASE_AS_OFFSET}
472 	 *
473 	 * @param deltaBaseAsOffset
474 	 *            boolean indicating whether delta base can be stored as an
475 	 *            offset.
476 	 */
477 	public void setDeltaBaseAsOffset(boolean deltaBaseAsOffset) {
478 		this.deltaBaseAsOffset = deltaBaseAsOffset;
479 	}
480 
481 	/**
482 	 * Check whether the writer will create new deltas on the fly.
483 	 *
484 	 * Default setting: {@value #DEFAULT_DELTA_COMPRESS}
485 	 *
486 	 * @return true if the writer will create a new delta when either
487 	 *         {@link #isReuseDeltas()} is false, or no suitable delta is
488 	 *         available for reuse.
489 	 */
490 	public boolean isDeltaCompress() {
491 		return deltaCompress;
492 	}
493 
494 	/**
495 	 * Set whether or not the writer will create new deltas on the fly.
496 	 *
497 	 * Default setting: {@value #DEFAULT_DELTA_COMPRESS}
498 	 *
499 	 * @param deltaCompress
500 	 *            true to create deltas when {@link #isReuseDeltas()} is false,
501 	 *            or when a suitable delta isn't available for reuse. Set to
502 	 *            false to write whole objects instead.
503 	 */
504 	public void setDeltaCompress(boolean deltaCompress) {
505 		this.deltaCompress = deltaCompress;
506 	}
507 
508 	/**
509 	 * Get maximum depth of delta chain set up for the writer.
510 	 *
511 	 * Generated chains are not longer than this value.
512 	 *
513 	 * Default setting: {@value #DEFAULT_MAX_DELTA_DEPTH}
514 	 *
515 	 * @return maximum delta chain depth.
516 	 */
517 	public int getMaxDeltaDepth() {
518 		return maxDeltaDepth;
519 	}
520 
521 	/**
522 	 * Set up maximum depth of delta chain for the writer.
523 	 *
524 	 * Generated chains are not longer than this value. Too low value causes low
525 	 * compression level, while too big makes unpacking (reading) longer.
526 	 *
527 	 * Default setting: {@value #DEFAULT_MAX_DELTA_DEPTH}
528 	 *
529 	 * @param maxDeltaDepth
530 	 *            maximum delta chain depth.
531 	 */
532 	public void setMaxDeltaDepth(int maxDeltaDepth) {
533 		this.maxDeltaDepth = maxDeltaDepth;
534 	}
535 
536 	/**
537 	 * Whether existing delta chains should be cut at
538 	 * {@link #getMaxDeltaDepth()}.
539 	 *
540 	 * @return true if existing delta chains should be cut at
541 	 *         {@link #getMaxDeltaDepth()}. Default is false, allowing existing
542 	 *         chains to be of any length.
543 	 * @since 3.0
544 	 */
545 	public boolean getCutDeltaChains() {
546 		return cutDeltaChains;
547 	}
548 
549 	/**
550 	 * Enable cutting existing delta chains at {@link #getMaxDeltaDepth()}.
551 	 *
552 	 * By default this is disabled and existing chains are kept at whatever
553 	 * length a prior packer was configured to create. This allows objects to be
554 	 * packed one with a large depth (for example 250), and later to quickly
555 	 * repack the repository with a shorter depth (such as 50), but reusing the
556 	 * complete delta chains created by the earlier 250 depth.
557 	 *
558 	 * @param cut
559 	 *            true to cut existing chains.
560 	 * @since 3.0
561 	 */
562 	public void setCutDeltaChains(boolean cut) {
563 		cutDeltaChains = cut;
564 	}
565 
566 	/**
567 	 * Whether all of refs/* should be packed in a single pack.
568 	 *
569 	 * @return true if all of refs/* should be packed in a single pack. Default
570 	 *         is false, packing a separate GC_REST pack for references outside
571 	 *         of refs/heads/* and refs/tags/*.
572 	 * @since 4.9
573 	 */
574 	public boolean getSinglePack() {
575 		return singlePack;
576 	}
577 
578 	/**
579 	 * If {@code true}, packs a single GC pack for all objects reachable from
580 	 * refs/*. Otherwise packs the GC pack with objects reachable from
581 	 * refs/heads/* and refs/tags/*, and a GC_REST pack with the remaining
582 	 * reachable objects. Disabled by default, packing GC and GC_REST.
583 	 *
584 	 * @param single
585 	 *            true to pack a single GC pack rather than GC and GC_REST packs
586 	 * @since 4.9
587 	 */
588 	public void setSinglePack(boolean single) {
589 		singlePack = single;
590 	}
591 
592 	/**
593 	 * Get the number of objects to try when looking for a delta base.
594 	 *
595 	 * This limit is per thread, if 4 threads are used the actual memory used
596 	 * will be 4 times this value.
597 	 *
598 	 * Default setting: {@value #DEFAULT_DELTA_SEARCH_WINDOW_SIZE}
599 	 *
600 	 * @return the object count to be searched.
601 	 */
602 	public int getDeltaSearchWindowSize() {
603 		return deltaSearchWindowSize;
604 	}
605 
606 	/**
607 	 * Set the number of objects considered when searching for a delta base.
608 	 *
609 	 * Default setting: {@value #DEFAULT_DELTA_SEARCH_WINDOW_SIZE}
610 	 *
611 	 * @param objectCount
612 	 *            number of objects to search at once. Must be at least 2.
613 	 */
614 	public void setDeltaSearchWindowSize(int objectCount) {
615 		if (objectCount <= 2)
616 			setDeltaCompress(false);
617 		else
618 			deltaSearchWindowSize = objectCount;
619 	}
620 
621 	/**
622 	 * Get maximum number of bytes to put into the delta search window.
623 	 *
624 	 * Default setting is 0, for an unlimited amount of memory usage. Actual
625 	 * memory used is the lower limit of either this setting, or the sum of
626 	 * space used by at most {@link #getDeltaSearchWindowSize()} objects.
627 	 *
628 	 * This limit is per thread, if 4 threads are used the actual memory limit
629 	 * will be 4 times this value.
630 	 *
631 	 * @return the memory limit.
632 	 */
633 	public long getDeltaSearchMemoryLimit() {
634 		return deltaSearchMemoryLimit;
635 	}
636 
637 	/**
638 	 * Set the maximum number of bytes to put into the delta search window.
639 	 *
640 	 * Default setting is 0, for an unlimited amount of memory usage. If the
641 	 * memory limit is reached before {@link #getDeltaSearchWindowSize()} the
642 	 * window size is temporarily lowered.
643 	 *
644 	 * @param memoryLimit
645 	 *            Maximum number of bytes to load at once, 0 for unlimited.
646 	 */
647 	public void setDeltaSearchMemoryLimit(long memoryLimit) {
648 		deltaSearchMemoryLimit = memoryLimit;
649 	}
650 
651 	/**
652 	 * Get the size of the in-memory delta cache.
653 	 *
654 	 * This limit is for the entire writer, even if multiple threads are used.
655 	 *
656 	 * Default setting: {@value #DEFAULT_DELTA_CACHE_SIZE}
657 	 *
658 	 * @return maximum number of bytes worth of delta data to cache in memory.
659 	 *         If 0 the cache is infinite in size (up to the JVM heap limit
660 	 *         anyway). A very tiny size such as 1 indicates the cache is
661 	 *         effectively disabled.
662 	 */
663 	public long getDeltaCacheSize() {
664 		return deltaCacheSize;
665 	}
666 
667 	/**
668 	 * Set the maximum number of bytes of delta data to cache.
669 	 *
670 	 * During delta search, up to this many bytes worth of small or hard to
671 	 * compute deltas will be stored in memory. This cache speeds up writing by
672 	 * allowing the cached entry to simply be dumped to the output stream.
673 	 *
674 	 * Default setting: {@value #DEFAULT_DELTA_CACHE_SIZE}
675 	 *
676 	 * @param size
677 	 *            number of bytes to cache. Set to 0 to enable an infinite
678 	 *            cache, set to 1 (an impossible size for any delta) to disable
679 	 *            the cache.
680 	 */
681 	public void setDeltaCacheSize(long size) {
682 		deltaCacheSize = size;
683 	}
684 
685 	/**
686 	 * Maximum size in bytes of a delta to cache.
687 	 *
688 	 * Default setting: {@value #DEFAULT_DELTA_CACHE_LIMIT}
689 	 *
690 	 * @return maximum size (in bytes) of a delta that should be cached.
691 	 */
692 	public int getDeltaCacheLimit() {
693 		return deltaCacheLimit;
694 	}
695 
696 	/**
697 	 * Set the maximum size of a delta that should be cached.
698 	 *
699 	 * During delta search, any delta smaller than this size will be cached, up
700 	 * to the {@link #getDeltaCacheSize()} maximum limit. This speeds up writing
701 	 * by allowing these cached deltas to be output as-is.
702 	 *
703 	 * Default setting: {@value #DEFAULT_DELTA_CACHE_LIMIT}
704 	 *
705 	 * @param size
706 	 *            maximum size (in bytes) of a delta to be cached.
707 	 */
708 	public void setDeltaCacheLimit(int size) {
709 		deltaCacheLimit = size;
710 	}
711 
712 	/**
713 	 * Get the maximum file size that will be delta compressed.
714 	 *
715 	 * Files bigger than this setting will not be delta compressed, as they are
716 	 * more than likely already highly compressed binary data files that do not
717 	 * delta compress well, such as MPEG videos.
718 	 *
719 	 * Default setting: {@value #DEFAULT_BIG_FILE_THRESHOLD}
720 	 *
721 	 * @return the configured big file threshold.
722 	 */
723 	public int getBigFileThreshold() {
724 		return bigFileThreshold;
725 	}
726 
727 	/**
728 	 * Set the maximum file size that should be considered for deltas.
729 	 *
730 	 * Default setting: {@value #DEFAULT_BIG_FILE_THRESHOLD}
731 	 *
732 	 * @param bigFileThreshold
733 	 *            the limit, in bytes.
734 	 */
735 	public void setBigFileThreshold(int bigFileThreshold) {
736 		this.bigFileThreshold = bigFileThreshold;
737 	}
738 
739 	/**
740 	 * Get the compression level applied to objects in the pack.
741 	 *
742 	 * Default setting: {@value java.util.zip.Deflater#DEFAULT_COMPRESSION}
743 	 *
744 	 * @return current compression level, see {@link java.util.zip.Deflater}.
745 	 */
746 	public int getCompressionLevel() {
747 		return compressionLevel;
748 	}
749 
750 	/**
751 	 * Set the compression level applied to objects in the pack.
752 	 *
753 	 * Default setting: {@value java.util.zip.Deflater#DEFAULT_COMPRESSION}
754 	 *
755 	 * @param level
756 	 *            compression level, must be a valid level recognized by the
757 	 *            {@link java.util.zip.Deflater} class.
758 	 */
759 	public void setCompressionLevel(int level) {
760 		compressionLevel = level;
761 	}
762 
763 	/**
764 	 * Get the number of threads used during delta compression.
765 	 *
766 	 * Default setting: 0 (auto-detect processors)
767 	 *
768 	 * @return number of threads used for delta compression. 0 will auto-detect
769 	 *         the threads to the number of available processors.
770 	 */
771 	public int getThreads() {
772 		return threads;
773 	}
774 
775 	/**
776 	 * Set the number of threads to use for delta compression.
777 	 *
778 	 * During delta compression, if there are enough objects to be considered
779 	 * the writer will start up concurrent threads and allow them to compress
780 	 * different sections of the repository concurrently.
781 	 *
782 	 * An application thread pool can be set by {@link #setExecutor(Executor)}.
783 	 * If not set a temporary pool will be created by the writer, and torn down
784 	 * automatically when compression is over.
785 	 *
786 	 * Default setting: 0 (auto-detect processors)
787 	 *
788 	 * @param threads
789 	 *            number of threads to use. If &lt;= 0 the number of available
790 	 *            processors for this JVM is used.
791 	 */
792 	public void setThreads(int threads) {
793 		this.threads = threads;
794 	}
795 
796 	/**
797 	 * Get the preferred thread pool to execute delta search on.
798 	 *
799 	 * @return the preferred thread pool to execute delta search on.
800 	 */
801 	public Executor getExecutor() {
802 		return executor;
803 	}
804 
805 	/**
806 	 * Set the executor to use when using threads.
807 	 *
808 	 * During delta compression if the executor is non-null jobs will be queued
809 	 * up on it to perform delta compression in parallel. Aside from setting the
810 	 * executor, the caller must set {@link #setThreads(int)} to enable threaded
811 	 * delta search.
812 	 *
813 	 * @param executor
814 	 *            executor to use for threads. Set to null to create a temporary
815 	 *            executor just for the writer.
816 	 */
817 	public void setExecutor(Executor executor) {
818 		this.executor = executor;
819 	}
820 
821 	/**
822 	 * Get the pack index file format version this instance creates.
823 	 *
824 	 * Default setting: {@value #DEFAULT_INDEX_VERSION}
825 	 *
826 	 * @return the index version, the special version 0 designates the oldest
827 	 *         (most compatible) format available for the objects.
828 	 * @see PackIndexWriter
829 	 */
830 	public int getIndexVersion() {
831 		return indexVersion;
832 	}
833 
834 	/**
835 	 * Set the pack index file format version this instance will create.
836 	 *
837 	 * Default setting: {@value #DEFAULT_INDEX_VERSION}
838 	 *
839 	 * @param version
840 	 *            the version to write. The special version 0 designates the
841 	 *            oldest (most compatible) format available for the objects.
842 	 * @see PackIndexWriter
843 	 */
844 	public void setIndexVersion(int version) {
845 		indexVersion = version;
846 	}
847 
848 	/**
849 	 * True if writer is allowed to build bitmaps for indexes.
850 	 *
851 	 * Default setting: {@value #DEFAULT_BUILD_BITMAPS}
852 	 *
853 	 * @return true if delta base is the writer can choose to output an index
854 	 *         with bitmaps.
855 	 * @since 3.0
856 	 */
857 	public boolean isBuildBitmaps() {
858 		return buildBitmaps;
859 	}
860 
861 	/**
862 	 * Set writer to allow building bitmaps for supported pack files.
863 	 *
864 	 * Index files can include bitmaps to speed up future ObjectWalks.
865 	 *
866 	 * Default setting: {@value #DEFAULT_BUILD_BITMAPS}
867 	 *
868 	 * @param buildBitmaps
869 	 *            boolean indicating whether bitmaps may be included in the
870 	 *            index.
871 	 * @since 3.0
872 	 */
873 	public void setBuildBitmaps(boolean buildBitmaps) {
874 		this.buildBitmaps = buildBitmaps;
875 	}
876 
877 	/**
878 	 * Get the count of most recent commits for which to build bitmaps.
879 	 *
880 	 * Default setting: {@value #DEFAULT_BITMAP_CONTIGUOUS_COMMIT_COUNT}
881 	 *
882 	 * @return the count of most recent commits for which to build bitmaps
883 	 * @since 4.2
884 	 */
885 	public int getBitmapContiguousCommitCount() {
886 		return bitmapContiguousCommitCount;
887 	}
888 
889 	/**
890 	 * Set the count of most recent commits for which to build bitmaps.
891 	 *
892 	 * Default setting: {@value #DEFAULT_BITMAP_CONTIGUOUS_COMMIT_COUNT}
893 	 *
894 	 * @param count
895 	 *            the count of most recent commits for which to build bitmaps
896 	 * @since 4.2
897 	 */
898 	public void setBitmapContiguousCommitCount(int count) {
899 		bitmapContiguousCommitCount = count;
900 	}
901 
902 	/**
903 	 * Get the count at which to switch from "bitmapRecentCommitSpan" to
904 	 * "bitmapDistantCommitSpan".
905 	 *
906 	 * Default setting: {@value #DEFAULT_BITMAP_RECENT_COMMIT_COUNT}
907 	 *
908 	 * @return the count for switching between recent and distant spans
909 	 * @since 4.2
910 	 */
911 	public int getBitmapRecentCommitCount() {
912 		return bitmapRecentCommitCount;
913 	}
914 
915 	/**
916 	 * Set the count at which to switch from "bitmapRecentCommitSpan" to
917 	 * "bitmapDistantCommitSpan".
918 	 *
919 	 * Default setting: {@value #DEFAULT_BITMAP_RECENT_COMMIT_COUNT}
920 	 *
921 	 * @param count
922 	 *            the count for switching between recent and distant spans
923 	 * @since 4.2
924 	 */
925 	public void setBitmapRecentCommitCount(int count) {
926 		bitmapRecentCommitCount = count;
927 	}
928 
929 	/**
930 	 * Get the span of commits when building bitmaps for recent history.
931 	 *
932 	 * Default setting: {@value #DEFAULT_BITMAP_RECENT_COMMIT_SPAN}
933 	 *
934 	 * @return the span of commits when building bitmaps for recent history
935 	 * @since 4.2
936 	 */
937 	public int getBitmapRecentCommitSpan() {
938 		return bitmapRecentCommitSpan;
939 	}
940 
941 	/**
942 	 * Set the span of commits when building bitmaps for recent history.
943 	 *
944 	 * Default setting: {@value #DEFAULT_BITMAP_RECENT_COMMIT_SPAN}
945 	 *
946 	 * @param span
947 	 *            the span of commits when building bitmaps for recent history
948 	 * @since 4.2
949 	 */
950 	public void setBitmapRecentCommitSpan(int span) {
951 		bitmapRecentCommitSpan = span;
952 	}
953 
954 	/**
955 	 * Get the span of commits when building bitmaps for distant history.
956 	 *
957 	 * Default setting: {@value #DEFAULT_BITMAP_DISTANT_COMMIT_SPAN}
958 	 *
959 	 * @return the span of commits when building bitmaps for distant history
960 	 * @since 4.2
961 	 */
962 	public int getBitmapDistantCommitSpan() {
963 		return bitmapDistantCommitSpan;
964 	}
965 
966 	/**
967 	 * Set the span of commits when building bitmaps for distant history.
968 	 *
969 	 * Default setting: {@value #DEFAULT_BITMAP_DISTANT_COMMIT_SPAN}
970 	 *
971 	 * @param span
972 	 *            the span of commits when building bitmaps for distant history
973 	 * @since 4.2
974 	 */
975 	public void setBitmapDistantCommitSpan(int span) {
976 		bitmapDistantCommitSpan = span;
977 	}
978 
979 	/**
980 	 * Get the count of branches deemed "excessive". If the count of branches in
981 	 * a repository exceeds this number and bitmaps are enabled, "inactive"
982 	 * branches will have fewer bitmaps than "active" branches.
983 	 *
984 	 * Default setting: {@value #DEFAULT_BITMAP_EXCESSIVE_BRANCH_COUNT}
985 	 *
986 	 * @return the count of branches deemed "excessive"
987 	 * @since 4.2
988 	 */
989 	public int getBitmapExcessiveBranchCount() {
990 		return bitmapExcessiveBranchCount;
991 	}
992 
993 	/**
994 	 * Set the count of branches deemed "excessive". If the count of branches in
995 	 * a repository exceeds this number and bitmaps are enabled, "inactive"
996 	 * branches will have fewer bitmaps than "active" branches.
997 	 *
998 	 * Default setting: {@value #DEFAULT_BITMAP_EXCESSIVE_BRANCH_COUNT}
999 	 *
1000 	 * @param count
1001 	 *            the count of branches deemed "excessive"
1002 	 * @since 4.2
1003 	 */
1004 	public void setBitmapExcessiveBranchCount(int count) {
1005 		bitmapExcessiveBranchCount = count;
1006 	}
1007 
1008 	/**
1009 	 * Get the the age in days that marks a branch as "inactive".
1010 	 *
1011 	 * Default setting: {@value #DEFAULT_BITMAP_INACTIVE_BRANCH_AGE_IN_DAYS}
1012 	 *
1013 	 * @return the age in days that marks a branch as "inactive"
1014 	 * @since 4.2
1015 	 */
1016 	public int getBitmapInactiveBranchAgeInDays() {
1017 		return bitmapInactiveBranchAgeInDays;
1018 	}
1019 
1020 	/**
1021 	 * Set the the age in days that marks a branch as "inactive".
1022 	 *
1023 	 * Default setting: {@value #DEFAULT_BITMAP_INACTIVE_BRANCH_AGE_IN_DAYS}
1024 	 *
1025 	 * @param ageInDays
1026 	 *            the age in days that marks a branch as "inactive"
1027 	 * @since 4.2
1028 	 */
1029 	public void setBitmapInactiveBranchAgeInDays(int ageInDays) {
1030 		bitmapInactiveBranchAgeInDays = ageInDays;
1031 	}
1032 
1033 	/**
1034 	 * Update properties by setting fields from the configuration.
1035 	 *
1036 	 * If a property's corresponding variable is not defined in the supplied
1037 	 * configuration, then it is left unmodified.
1038 	 *
1039 	 * @param rc
1040 	 *            configuration to read properties from.
1041 	 */
1042 	public void fromConfig(Config rc) {
1043 		setMaxDeltaDepth(rc.getInt("pack", "depth", getMaxDeltaDepth())); //$NON-NLS-1$ //$NON-NLS-2$
1044 		setDeltaSearchWindowSize(rc.getInt(
1045 				"pack", "window", getDeltaSearchWindowSize())); //$NON-NLS-1$ //$NON-NLS-2$
1046 		setDeltaSearchMemoryLimit(rc.getLong(
1047 				"pack", "windowmemory", getDeltaSearchMemoryLimit())); //$NON-NLS-1$ //$NON-NLS-2$
1048 		setDeltaCacheSize(rc.getLong(
1049 				"pack", "deltacachesize", getDeltaCacheSize())); //$NON-NLS-1$ //$NON-NLS-2$
1050 		setDeltaCacheLimit(rc.getInt(
1051 				"pack", "deltacachelimit", getDeltaCacheLimit())); //$NON-NLS-1$ //$NON-NLS-2$
1052 		setCompressionLevel(rc.getInt("pack", "compression", //$NON-NLS-1$ //$NON-NLS-2$
1053 				rc.getInt("core", "compression", getCompressionLevel()))); //$NON-NLS-1$ //$NON-NLS-2$
1054 		setIndexVersion(rc.getInt("pack", "indexversion", getIndexVersion())); //$NON-NLS-1$ //$NON-NLS-2$
1055 		setBigFileThreshold(rc.getInt(
1056 				"core", "bigfilethreshold", getBigFileThreshold())); //$NON-NLS-1$ //$NON-NLS-2$
1057 		setThreads(rc.getInt("pack", "threads", getThreads())); //$NON-NLS-1$ //$NON-NLS-2$
1058 
1059 		// These variables aren't standardized
1060 		//
1061 		setReuseDeltas(rc.getBoolean("pack", "reusedeltas", isReuseDeltas())); //$NON-NLS-1$ //$NON-NLS-2$
1062 		setReuseObjects(
1063 				rc.getBoolean("pack", "reuseobjects", isReuseObjects())); //$NON-NLS-1$ //$NON-NLS-2$
1064 		setDeltaCompress(
1065 				rc.getBoolean("pack", "deltacompression", isDeltaCompress())); //$NON-NLS-1$ //$NON-NLS-2$
1066 		setCutDeltaChains(
1067 				rc.getBoolean("pack", "cutdeltachains", getCutDeltaChains())); //$NON-NLS-1$ //$NON-NLS-2$
1068 		setSinglePack(
1069 				rc.getBoolean("pack", "singlepack", getSinglePack())); //$NON-NLS-1$ //$NON-NLS-2$
1070 		setBuildBitmaps(
1071 				rc.getBoolean("pack", "buildbitmaps", isBuildBitmaps())); //$NON-NLS-1$ //$NON-NLS-2$
1072 		setBitmapContiguousCommitCount(
1073 				rc.getInt("pack", "bitmapcontiguouscommitcount", //$NON-NLS-1$ //$NON-NLS-2$
1074 						getBitmapContiguousCommitCount()));
1075 		setBitmapRecentCommitCount(rc.getInt("pack", "bitmaprecentcommitcount", //$NON-NLS-1$ //$NON-NLS-2$
1076 				getBitmapRecentCommitCount()));
1077 		setBitmapRecentCommitSpan(rc.getInt("pack", "bitmaprecentcommitspan", //$NON-NLS-1$ //$NON-NLS-2$
1078 				getBitmapRecentCommitSpan()));
1079 		setBitmapDistantCommitSpan(rc.getInt("pack", "bitmapdistantcommitspan", //$NON-NLS-1$ //$NON-NLS-2$
1080 				getBitmapDistantCommitSpan()));
1081 		setBitmapExcessiveBranchCount(rc.getInt("pack", //$NON-NLS-1$
1082 				"bitmapexcessivebranchcount", getBitmapExcessiveBranchCount())); //$NON-NLS-1$
1083 		setBitmapInactiveBranchAgeInDays(
1084 				rc.getInt("pack", "bitmapinactivebranchageindays", //$NON-NLS-1$ //$NON-NLS-2$
1085 						getBitmapInactiveBranchAgeInDays()));
1086 	}
1087 
1088 	/** {@inheritDoc} */
1089 	@Override
1090 	public String toString() {
1091 		final StringBuilder b = new StringBuilder();
1092 		b.append("maxDeltaDepth=").append(getMaxDeltaDepth()); //$NON-NLS-1$
1093 		b.append(", deltaSearchWindowSize=").append(getDeltaSearchWindowSize()); //$NON-NLS-1$
1094 		b.append(", deltaSearchMemoryLimit=") //$NON-NLS-1$
1095 				.append(getDeltaSearchMemoryLimit());
1096 		b.append(", deltaCacheSize=").append(getDeltaCacheSize()); //$NON-NLS-1$
1097 		b.append(", deltaCacheLimit=").append(getDeltaCacheLimit()); //$NON-NLS-1$
1098 		b.append(", compressionLevel=").append(getCompressionLevel()); //$NON-NLS-1$
1099 		b.append(", indexVersion=").append(getIndexVersion()); //$NON-NLS-1$
1100 		b.append(", bigFileThreshold=").append(getBigFileThreshold()); //$NON-NLS-1$
1101 		b.append(", threads=").append(getThreads()); //$NON-NLS-1$
1102 		b.append(", reuseDeltas=").append(isReuseDeltas()); //$NON-NLS-1$
1103 		b.append(", reuseObjects=").append(isReuseObjects()); //$NON-NLS-1$
1104 		b.append(", deltaCompress=").append(isDeltaCompress()); //$NON-NLS-1$
1105 		b.append(", buildBitmaps=").append(isBuildBitmaps()); //$NON-NLS-1$
1106 		b.append(", bitmapContiguousCommitCount=") //$NON-NLS-1$
1107 				.append(getBitmapContiguousCommitCount());
1108 		b.append(", bitmapRecentCommitCount=") //$NON-NLS-1$
1109 				.append(getBitmapRecentCommitCount());
1110 		b.append(", bitmapRecentCommitSpan=") //$NON-NLS-1$
1111 				.append(getBitmapRecentCommitSpan());
1112 		b.append(", bitmapDistantCommitSpan=") //$NON-NLS-1$
1113 				.append(getBitmapDistantCommitSpan());
1114 		b.append(", bitmapExcessiveBranchCount=") //$NON-NLS-1$
1115 				.append(getBitmapExcessiveBranchCount());
1116 		b.append(", bitmapInactiveBranchAge=") //$NON-NLS-1$
1117 				.append(getBitmapInactiveBranchAgeInDays());
1118 		b.append(", singlePack=").append(getSinglePack()); //$NON-NLS-1$
1119 		return b.toString();
1120 	}
1121 }