TemporaryBuffer: fix toByteArray(limit)

Heap always copied whole blocks, which leads to AIOOBEs. LocalFile
didn't overwrite the method and thus caused NPEs.

Change-Id: Ia37d4a875df9f25d4825e6bc95fed7f0dff42afb
Signed-off-by: Thomas Wolf <thomas.wolf@paranor.ch>

1 files changed, 65 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/TemporaryBufferTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/TemporaryBufferTest.java
index 4e65ca7a4b..01dcde29bd 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/TemporaryBufferTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/TemporaryBufferTest.java
@@ -406,4 +406,69 @@ public class TemporaryBufferTest {
 			}
 		}
 	}
+
+	@Test
+	public void testHeapToByteArrayWithLimit() throws IOException {
+		int sz = 2 * Block.SZ;
+		try (TemporaryBuffer b = new TemporaryBuffer.Heap(sz / 2, sz)) {
+			for (int i = 0; i < sz; i++) {
+				b.write('a' + i % 26);
+			}
+			byte[] prefix = b.toByteArray(5);
+			assertEquals(5, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+			prefix = b.toByteArray(Block.SZ + 37);
+			assertEquals(Block.SZ + 37, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+			prefix = b.toByteArray(sz);
+			assertEquals(sz, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+			prefix = b.toByteArray(sz + 37);
+			assertEquals(sz, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+		}
+	}
+
+	@Test
+	public void testFileToByteArrayWithLimit() throws IOException {
+		@SuppressWarnings("resource") // Buffer is explicitly destroyed in finally block
+		TemporaryBuffer b = new TemporaryBuffer.LocalFile(null, 2 * Block.SZ);
+		int sz = 3 * Block.SZ;
+		try {
+			for (int i = 0; i < sz; i++) {
+				b.write('a' + i % 26);
+			}
+			b.close();
+			byte[] prefix = b.toByteArray(5);
+			assertEquals(5, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+			prefix = b.toByteArray(Block.SZ + 37);
+			assertEquals(Block.SZ + 37, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+			prefix = b.toByteArray(sz);
+			assertEquals(sz, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+			prefix = b.toByteArray(sz + 37);
+			assertEquals(sz, prefix.length);
+			for (int i = 0; i < prefix.length; i++) {
+				assertEquals('a' + i % 26, prefix[i]);
+			}
+		} finally {
+			b.destroy();
+		}
+	}
 }