private Pack writePack()

in org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/file/GC.java [1125:1269]
125 lines of code
21 McCabe index (conditional complexity)

	private Pack writePack(@NonNull Set<? extends ObjectId> want,
			@NonNull Set<? extends ObjectId> have, @NonNull Set<ObjectId> tags,
			Set<ObjectId> tagTargets, List<ObjectIdSet> excludeObjects)
			throws IOException {
		checkCancelled();
		File tmpPack = null;
		Map<PackExt, File> tmpExts = new TreeMap<>((o1, o2) -> {
			// INDEX entries must be returned last, so the pack
			// scanner does pick up the new pack until all the
			// PackExt entries have been written.
			if (o1 == o2) {
				return 0;
			}
			if (o1 == PackExt.INDEX) {
				return 1;
			}
			if (o2 == PackExt.INDEX) {
				return -1;
			}
			return Integer.signum(o1.hashCode() - o2.hashCode());
		});
		try (PackWriter pw = new PackWriter(
				pconfig,
				repo.newObjectReader())) {
			// prepare the PackWriter
			pw.setDeltaBaseAsOffset(true);
			pw.setReuseDeltaCommits(false);
			if (tagTargets != null) {
				pw.setTagTargets(tagTargets);
			}
			if (excludeObjects != null)
				for (ObjectIdSet idx : excludeObjects)
					pw.excludeObjects(idx);
			pw.preparePack(pm, want, have, PackWriter.NONE, tags);
			if (pw.getObjectCount() == 0)
				return null;
			checkCancelled();

			// create temporary files
			ObjectId id = pw.computeName();
			File packdir = repo.getObjectDatabase().getPackDirectory();
			packdir.mkdirs();
			tmpPack = File.createTempFile("gc_", ".pack_tmp", packdir); //$NON-NLS-1$ //$NON-NLS-2$
			final String tmpBase = tmpPack.getName()
					.substring(0, tmpPack.getName().lastIndexOf('.'));
			File tmpIdx = new File(packdir, tmpBase + ".idx_tmp"); //$NON-NLS-1$
			tmpExts.put(INDEX, tmpIdx);

			if (!tmpIdx.createNewFile())
				throw new IOException(MessageFormat.format(
						JGitText.get().cannotCreateIndexfile, tmpIdx.getPath()));

			// write the packfile
			try (FileOutputStream fos = new FileOutputStream(tmpPack);
					FileChannel channel = fos.getChannel();
					OutputStream channelStream = Channels
							.newOutputStream(channel)) {
				pw.writePack(pm, pm, channelStream);
				channel.force(true);
			}

			// write the packindex
			try (FileOutputStream fos = new FileOutputStream(tmpIdx);
					FileChannel idxChannel = fos.getChannel();
					OutputStream idxStream = Channels
							.newOutputStream(idxChannel)) {
				pw.writeIndex(idxStream);
				idxChannel.force(true);
			}

			if (pw.prepareBitmapIndex(pm)) {
				File tmpBitmapIdx = new File(packdir, tmpBase + ".bitmap_tmp"); //$NON-NLS-1$
				tmpExts.put(BITMAP_INDEX, tmpBitmapIdx);

				if (!tmpBitmapIdx.createNewFile())
					throw new IOException(MessageFormat.format(
							JGitText.get().cannotCreateIndexfile,
							tmpBitmapIdx.getPath()));

				try (FileOutputStream fos = new FileOutputStream(tmpBitmapIdx);
						FileChannel idxChannel = fos.getChannel();
						OutputStream idxStream = Channels
								.newOutputStream(idxChannel)) {
					pw.writeBitmapIndex(idxStream);
					idxChannel.force(true);
				}
			}

			// rename the temporary files to real files
			File packDir = repo.getObjectDatabase().getPackDirectory();
			PackFile realPack = new PackFile(packDir, id, PackExt.PACK);

			repo.getObjectDatabase().closeAllPackHandles(realPack);
			tmpPack.setReadOnly();

			FileUtils.rename(tmpPack, realPack, StandardCopyOption.ATOMIC_MOVE);
			for (Map.Entry<PackExt, File> tmpEntry : tmpExts.entrySet()) {
				File tmpExt = tmpEntry.getValue();
				tmpExt.setReadOnly();

				PackFile realExt = new PackFile(packDir, id, tmpEntry.getKey());
				try {
					FileUtils.rename(tmpExt, realExt,
							StandardCopyOption.ATOMIC_MOVE);
				} catch (IOException e) {
					File newExt = new File(realExt.getParentFile(),
							realExt.getName() + ".new"); //$NON-NLS-1$
					try {
						FileUtils.rename(tmpExt, newExt,
								StandardCopyOption.ATOMIC_MOVE);
					} catch (IOException e2) {
						newExt = tmpExt;
						e = e2;
					}
					throw new IOException(MessageFormat.format(
							JGitText.get().panicCantRenameIndexFile, newExt,
							realExt), e);
				}
			}
			boolean interrupted = false;
			try {
				FileSnapshot snapshot = FileSnapshot.save(realPack);
				if (pconfig.doWaitPreventRacyPack(snapshot.size())) {
					snapshot.waitUntilNotRacy();
				}
			} catch (InterruptedException e) {
				interrupted = true;
			}
			try {
				return repo.getObjectDatabase().openPack(realPack);
			} finally {
				if (interrupted) {
					// Re-set interrupted flag
					Thread.currentThread().interrupt();
				}
			}
		} finally {
			if (tmpPack != null && tmpPack.exists())
				tmpPack.delete();
			for (File tmpExt : tmpExts.values()) {
				if (tmpExt.exists())
					tmpExt.delete();
			}
		}
	}