Allow configurable ObjectCheckers in fetch

RecievePack already honors fsck settings for safeForWindows and
safeForMacOS.  Allow those same checks to be performed during fetch
through a caller-configurable ObjectChecker.

Default the fetch fsck options to match the current platform, as
it can be reasonably assumed the repository will be accessed here.

Change-Id: I3c0f411fad209c6bd8fb9c4acf5c55a6799a6a2a

org.eclipse.jgit/src/org/eclipse/jgit/transport/BasePackFetchConnection.java

@@ -757,7 +757,7 @@ private void receivePack(final ProgressMonitor monitor,
 		try {
 			PackParser parser = ins.newPackParser(input);
 			parser.setAllowThin(thinPack);
-			parser.setObjectChecking(transport.isCheckFetchedObjects());
+			parser.setObjectChecker(transport.getObjectChecker());
 			parser.setLockMessage(lockMessage);
 			packLock = parser.parse(monitor);
 			ins.flush();

org.eclipse.jgit/src/org/eclipse/jgit/transport/BundleFetchConnection.java

@@ -187,7 +187,7 @@ protected void doFetch(final ProgressMonitor monitor,
 			try {
 				PackParser parser = ins.newPackParser(bin);
 				parser.setAllowThin(true);
-				parser.setObjectChecking(transport.isCheckFetchedObjects());
+				parser.setObjectChecker(transport.getObjectChecker());
 				parser.setLockMessage(lockMessage);
 				packLock = parser.parse(NullProgressMonitor.INSTANCE);
 				ins.flush();

org.eclipse.jgit/src/org/eclipse/jgit/transport/TransferConfig.java

@@ -48,8 +48,10 @@
 
 import org.eclipse.jgit.lib.Config;
 import org.eclipse.jgit.lib.Config.SectionParser;
+import org.eclipse.jgit.lib.ObjectChecker;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.util.SystemReader;
 
 /**
  * The standard "transfer", "fetch", "receive", and "uploadpack" configuration
@@ -63,7 +65,10 @@ public TransferConfig parse(final Config cfg) {
 		}
 	};
 
-	private final boolean fetchFsck;
+	private final boolean checkReceivedObjects;
+	private final boolean allowLeadingZeroFileMode;
+	private final boolean safeForWindows;
+	private final boolean safeForMacOS;
 	private final boolean allowTipSha1InWant;
 	private final String[] hideRefs;
 
@@ -72,9 +77,17 @@ public TransferConfig parse(final Config cfg) {
 	}
 
 	private TransferConfig(final Config rc) {
-		fetchFsck = rc.getBoolean(
+		checkReceivedObjects = rc.getBoolean(
 				"fetch", "fsckobjects", //$NON-NLS-1$ //$NON-NLS-2$
 				rc.getBoolean("transfer", "fsckobjects", false)); //$NON-NLS-1$ //$NON-NLS-2$
+		allowLeadingZeroFileMode = checkReceivedObjects
+				&& rc.getBoolean("fsck", "allowLeadingZeroFileMode", false); //$NON-NLS-1$ //$NON-NLS-2$
+		safeForWindows = checkReceivedObjects
+				&& rc.getBoolean("fsck", "safeForWindows", //$NON-NLS-1$ //$NON-NLS-2$
+						SystemReader.getInstance().isWindows());
+		safeForMacOS = checkReceivedObjects
+				&& rc.getBoolean("fsck", "safeForMacOS", //$NON-NLS-1$ //$NON-NLS-2$
+						SystemReader.getInstance().isMacOS());
 
 		allowTipSha1InWant = rc.getBoolean(
 				"uploadpack", "allowtipsha1inwant", false); //$NON-NLS-1$ //$NON-NLS-2$
@@ -83,9 +96,25 @@ private TransferConfig(final Config rc) {
 
 	/**
 	 * @return strictly verify received objects?
+	 * @deprecated use {@link #newObjectChecker()} instead.
 	 */
+	@Deprecated
 	public boolean isFsckObjects() {
-		return fetchFsck;
+		return checkReceivedObjects;
+	}
+
+	/**
+	 * @return checker to verify fetched objects, or null if checking is not
+	 *         enabled in the repository configuration.
+	 * @since 3.6
+	 */
+	public ObjectChecker newObjectChecker() {
+		if (!checkReceivedObjects)
+			return null;
+		return new ObjectChecker()
+			.setAllowLeadingZeroFileMode(allowLeadingZeroFileMode)
+			.setSafeForWindows(safeForWindows)
+			.setSafeForMacOS(safeForMacOS);
 	}
 
 	/**

org.eclipse.jgit/src/org/eclipse/jgit/transport/Transport.java

@@ -75,6 +75,7 @@
 import org.eclipse.jgit.internal.JGitText;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.NullProgressMonitor;
+import org.eclipse.jgit.lib.ObjectChecker;
 import org.eclipse.jgit.lib.ProgressMonitor;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
@@ -746,7 +747,7 @@ private static String findTrackingRefName(final String remoteName,
 	private boolean dryRun;
 
 	/** Should an incoming (fetch) transfer validate objects? */
-	private boolean checkFetchedObjects;
+	private ObjectChecker objectChecker;
 
 	/** Should refs no longer on the source be pruned from the destination? */
 	private boolean removeDeletedRefs;
@@ -775,7 +776,7 @@ protected Transport(final Repository local, final URIish uri) {
 		final TransferConfig tc = local.getConfig().get(TransferConfig.KEY);
 		this.local = local;
 		this.uri = uri;
-		this.checkFetchedObjects = tc.isFsckObjects();
+		this.objectChecker = tc.newObjectChecker();
 		this.credentialsProvider = CredentialsProvider.getDefault();
 	}
 
@@ -787,7 +788,7 @@ protected Transport(final Repository local, final URIish uri) {
 	protected Transport(final URIish uri) {
 		this.uri = uri;
 		this.local = null;
-		this.checkFetchedObjects = true;
+		this.objectChecker = new ObjectChecker();
 		this.credentialsProvider = CredentialsProvider.getDefault();
 	}
 
@@ -873,16 +874,38 @@ public void setFetchThin(final boolean fetchThin) {
 	 *         client side of the connection.
 	 */
 	public boolean isCheckFetchedObjects() {
-		return checkFetchedObjects;
+		return getObjectChecker() != null;
 	}
 
 	/**
 	 * @param check
 	 *            true to enable checking received objects; false to assume all
 	 *            received objects are valid.
+	 * @see #setObjectChecker(ObjectChecker)
 	 */
 	public void setCheckFetchedObjects(final boolean check) {
-		checkFetchedObjects = check;
+		if (check && objectChecker == null)
+			setObjectChecker(new ObjectChecker());
+		else if (!check && objectChecker != null)
+			setObjectChecker(null);
+	}
+
+	/**
+	 * @return configured object checker for received objects, or null.
+	 * @since 3.6
+	 */
+	public ObjectChecker getObjectChecker() {
+		return objectChecker;
+	}
+
+	/**
+	 * @param impl
+	 *            if non-null the object checking instance to verify each
+	 *            received object with; null to disable object checking.
+	 * @since 3.6
+	 */
+	public void setObjectChecker(ObjectChecker impl) {
+		objectChecker = impl;
 	}
 
 	/**

org.eclipse.jgit/src/org/eclipse/jgit/transport/WalkFetchConnection.java

@@ -193,7 +193,7 @@ class WalkFetchConnection extends BaseFetchConnection {
 	WalkFetchConnection(final WalkTransport t, final WalkRemoteObjectDatabase w) {
 		Transport wt = (Transport)t;
 		local = wt.local;
-		objCheck = wt.isCheckFetchedObjects() ? new ObjectChecker() : null;
+		objCheck = wt.getObjectChecker();
 		inserter = local.newObjectInserter();
 		reader = local.newObjectReader();