Add setLength(long) to DirCacheEntry

Applications should favor the long style interface, especially when
their source input is a long type, e.g. coming from java.io.File.
This way when the index format is later changed to support a
larger file size than 2 GiB we can handle it by just changing the
entry code, and not need to fix a lot of applications.

Change-Id: I332563caeb110014e2d544dc33050ce67ae9e897
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

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

@@ -328,6 +328,7 @@ shortReadOfBlock=Short read of block.
 shortReadOfOptionalDIRCExtensionExpectedAnotherBytes=Short read of optional DIRC extension {0}; expected another {1} bytes within the section.
 shortSkipOfBlock=Short skip of block.
 similarityScoreMustBeWithinBounds=Similarity score must be between 0 and 100.
+sizeExceeds2GB=Path {0} size {1} exceeds 2 GiB limit.
 smartHTTPPushDisabled=smart HTTP push disabled
 sourceDestinationMustMatch=Source/Destination must match.
 sourceIsNotAWildcard=Source is not a wildcard.

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

@@ -387,6 +387,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String shortReadOfOptionalDIRCExtensionExpectedAnotherBytes;
 	/***/ public String shortSkipOfBlock;
 	/***/ public String similarityScoreMustBeWithinBounds;
+	/***/ public String sizeExceeds2GB;
 	/***/ public String smartHTTPPushDisabled;
 	/***/ public String sourceDestinationMustMatch;
 	/***/ public String sourceIsNotAWildcard;

org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheEntry.java

@@ -486,6 +486,22 @@ public class DirCacheEntry {
 		NB.encodeInt32(info, infoOffset + P_SIZE, sz);
 	}
 
+	/**
+	 * Set the cached size (in bytes) of this file.
+	 *
+	 * @param sz
+	 *            new cached size of the file, as bytes.
+	 * @throws IllegalArgumentException
+	 *             if the size exceeds the 2 GiB barrier imposed by current file
+	 *             format limitations.
+	 */
+	public void setLength(final long sz) {
+		if (Integer.MAX_VALUE <= sz)
+			throw new IllegalArgumentException(MessageFormat.format(JGitText
+					.get().sizeExceeds2GB, getPathString(), sz));
+		setLength((int) sz);
+	}
+
 	/**
 	 * Obtain the ObjectId for the entry.
 	 * <p>