Improve LargeObjectException reporting

Use 3 different types of LargeObjectException for the 3 major ways
that we can fail to load an object.  For each of these use a unique
string translation which describes the root cause better than just
the ObjectId.name() does.

Change-Id: I810c98d5691b74af9fc6cbd46fc9879e35a7bdca
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

7 files changed, 106 insertions, 13 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
index fc12e57135..ea40fe8847 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/JGitText.java
@@ -276,6 +276,10 @@ public class JGitText extends TranslationBundle {
 	/***/ public String invalidWindowSize;
 	/***/ public String isAStaticFlagAndHasNorevWalkInstance;
 	/***/ public String kNotInRange;
+	/***/ public String largeObjectException;
+	/***/ public String largeObjectOutOfMemory;
+	/***/ public String largeObjectExceedsByteArray;
+	/***/ public String largeObjectExceedsLimit;
 	/***/ public String lengthExceedsMaximumArraySize;
 	/***/ public String listingAlternates;
 	/***/ public String localObjectsIncomplete;
@@ -433,6 +437,7 @@ public class JGitText extends TranslationBundle {
 	/***/ public String unknownDIRCVersion;
 	/***/ public String unknownHost;
 	/***/ public String unknownIndexVersionOrCorruptIndex;
+	/***/ public String unknownObject;
 	/***/ public String unknownObjectType;
 	/***/ public String unknownRepositoryFormat2;
 	/***/ public String unknownRepositoryFormat;
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/errors/LargeObjectException.java b/org.eclipse.jgit/src/org/eclipse/jgit/errors/LargeObjectException.java
index f77aecbb42..a1107dc35f 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/errors/LargeObjectException.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/errors/LargeObjectException.java
@@ -43,6 +43,9 @@
 
 package org.eclipse.jgit.errors;
 
+import java.text.MessageFormat;
+
+import org.eclipse.jgit.JGitText;
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.ObjectId;
 
@@ -73,6 +76,13 @@ public class LargeObjectException extends RuntimeException {
 		return objectId;
 	}
 
+	/** @return either the hex encoded name of the object, or 'unknown object'. */
+	protected String getObjectName() {
+		if (getObjectId() != null)
+			return getObjectId().name();
+		return JGitText.get().unknownObject;
+	}
+
 	/**
 	 * Set the identity of the object, if its not already set.
 	 *
@@ -86,6 +96,68 @@ public class LargeObjectException extends RuntimeException {
 
 	@Override
 	public String getMessage() {
-		return objectId != null ? objectId.name() : getClass().getSimpleName();
+		return MessageFormat.format(JGitText.get().largeObjectException,
+				getObjectName());
+	}
+
+	/** An error caused by the JVM being out of heap space. */
+	public static class OutOfMemory extends LargeObjectException {
+		private static final long serialVersionUID = 1L;
+
+		/**
+		 * Construct a wrapper around the original OutOfMemoryError.
+		 *
+		 * @param cause
+		 *            the original root cause.
+		 */
+		public OutOfMemory(OutOfMemoryError cause) {
+			initCause(cause);
+		}
+
+		@Override
+		public String getMessage() {
+			return MessageFormat.format(JGitText.get().largeObjectOutOfMemory,
+					getObjectName());
+		}
+	}
+
+	/** Object size exceeds JVM limit of 2 GiB per byte array. */
+	public static class ExceedsByteArrayLimit extends LargeObjectException {
+		private static final long serialVersionUID = 1L;
+
+		@Override
+		public String getMessage() {
+			return MessageFormat
+					.format(JGitText.get().largeObjectExceedsByteArray,
+							getObjectName());
+		}
+	}
+
+	/** Object size exceeds the caller's upper limit. */
+	public static class ExceedsLimit extends LargeObjectException {
+		private static final long serialVersionUID = 1L;
+
+		private final long limit;
+
+		private final long size;
+
+		/**
+		 * Construct an exception for a particular size being exceeded.
+		 *
+		 * @param limit
+		 *            the limit the caller imposed on the object.
+		 * @param size
+		 *            the actual size of the object.
+		 */
+		public ExceedsLimit(long limit, long size) {
+			this.limit = limit;
+			this.size = size;
+		}
+
+		@Override
+		public String getMessage() {
+			return MessageFormat.format(JGitText.get().largeObjectExceedsLimit,
+					getObjectName(), limit, size);
+		}
 	}
 }
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectLoader.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectLoader.java
index b7e58ea156..0fc3bce65b 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectLoader.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/ObjectLoader.java
@@ -139,7 +139,7 @@ public abstract class ObjectLoader {
 		try {
 			return cloneArray(cached);
 		} catch (OutOfMemoryError tooBig) {
-			throw new LargeObjectException();
+			throw new LargeObjectException.OutOfMemory(tooBig);
 		}
 	}
 
@@ -195,14 +195,17 @@ public abstract class ObjectLoader {
 		ObjectStream in = openStream();
 		try {
 			long sz = in.getSize();
-			if (sizeLimit < sz || Integer.MAX_VALUE < sz)
-				throw new LargeObjectException();
+			if (sizeLimit < sz)
+				throw new LargeObjectException.ExceedsLimit(sizeLimit, sz);
+
+			if (Integer.MAX_VALUE < sz)
+				throw new LargeObjectException.ExceedsByteArrayLimit();
 
 			byte[] buf;
 			try {
 				buf = new byte[(int) sz];
 			} catch (OutOfMemoryError notEnoughHeap) {
-				throw new LargeObjectException();
+				throw new LargeObjectException.OutOfMemory(notEnoughHeap);
 			}
 
 			IO.readFully(in, buf, 0, buf.length);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedDeltaObject.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedDeltaObject.java
index 02e218216d..2b98f107f8 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedDeltaObject.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedDeltaObject.java
@@ -157,7 +157,9 @@ class LargePackedDeltaObject extends ObjectLoader {
 		try {
 			throw new LargeObjectException(getObjectId());
 		} catch (IOException cannotObtainId) {
-			throw new LargeObjectException();
+			LargeObjectException err = new LargeObjectException();
+			err.initCause(cannotObtainId);
+			throw err;
 		}
 	}
 
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedWholeObject.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedWholeObject.java
index 9f5b804ce4..9550be4e1d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedWholeObject.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/LargePackedWholeObject.java
@@ -97,7 +97,9 @@ class LargePackedWholeObject extends ObjectLoader {
 		try {
 			throw new LargeObjectException(getObjectId());
 		} catch (IOException cannotObtainId) {
-			throw new LargeObjectException();
+			LargeObjectException err = new LargeObjectException();
+			err.initCause(cannotObtainId);
+			throw err;
 		}
 	}
 
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/UnpackedObject.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/UnpackedObject.java
index 78e7b10a7d..4065019dc5 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/UnpackedObject.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/file/UnpackedObject.java
@@ -125,8 +125,12 @@ public class UnpackedObject {
 				if (hdr[p.value++] != 0)
 					throw new CorruptObjectException(id,
 							JGitText.get().corruptObjectGarbageAfterSize);
-				if (path == null && Integer.MAX_VALUE < size)
-					throw new LargeObjectException(id.copy());
+				if (path == null && Integer.MAX_VALUE < size) {
+					LargeObjectException.ExceedsByteArrayLimit e;
+					e = new LargeObjectException.ExceedsByteArrayLimit();
+					e.setObjectId(id);
+					throw e;
+				}
 				if (size < wc.getStreamFileThreshold() || path == null) {
 					byte[] data = new byte[(int) size];
 					int n = avail - p.value;
@@ -163,8 +167,12 @@ public class UnpackedObject {
 							JGitText.get().corruptObjectInvalidType);
 				}
 
-				if (path == null && Integer.MAX_VALUE < size)
-					throw new LargeObjectException(id.copy());
+				if (path == null && Integer.MAX_VALUE < size) {
+					LargeObjectException.ExceedsByteArrayLimit e;
+					e = new LargeObjectException.ExceedsByteArrayLimit();
+					e.setObjectId(id);
+					throw e;
+				}
 				if (size < wc.getStreamFileThreshold() || path == null) {
 					in.reset();
 					IO.skipFully(in, p);
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/DeltaWindow.java b/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/DeltaWindow.java
index d5296a03e3..6a71ad7dcf 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/DeltaWindow.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/storage/pack/DeltaWindow.java
@@ -424,8 +424,9 @@ class DeltaWindow {
 			try {
 				idx = new DeltaIndex(buffer(ent));
 			} catch (OutOfMemoryError noMemory) {
-				LargeObjectException e = new LargeObjectException(ent.object);
-				e.initCause(noMemory);
+				LargeObjectException.OutOfMemory e;
+				e = new LargeObjectException.OutOfMemory(noMemory);
+				e.setObjectId(ent.object);
 				throw e;
 			}
 			if (0 < maxMemory)