Merge pull request #126 from archiecobbs/master

Fix incorrect behavior when reading a BLOB via ResultSet.getBytes().

src/main/java/org/sqlite/core/NativeDB.c

@@ -579,13 +579,21 @@ JNIEXPORT jstring JNICALL Java_org_sqlite_core_NativeDB_column_1text(
 JNIEXPORT jbyteArray JNICALL Java_org_sqlite_core_NativeDB_column_1blob(
         JNIEnv *env, jobject this, jlong stmt, jint col)
 {
-    jsize length;
     jbyteArray jBlob;
     jbyte *a;
+    // The value returned by sqlite3_column_type() is only meaningful if no type conversions have occurred
+    int type = sqlite3_column_type(toref(stmt), col);
     const void *blob = sqlite3_column_blob(toref(stmt), col);
-    if (!blob) return NULL;
+    jsize length = sqlite3_column_bytes(toref(stmt), col);
+    if (!blob) {
+        if (type == SQLITE_NULL) {
+            return NULL;
+        } else if (length == 0) {
+            // The return value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
+            return (*env)->NewByteArray(env, 0);
+        }
+    }
 
-    length = sqlite3_column_bytes(toref(stmt), col);
     jBlob = (*env)->NewByteArray(env, length);
     if (!jBlob) { throwex_outofmemory(env); return 0; }
 

src/test/java/org/sqlite/QueryTest.java

@@ -9,7 +9,10 @@
 //--------------------------------------
 package org.sqlite;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 import java.sql.Connection;
 import java.sql.DriverManager;
@@ -19,10 +22,8 @@
 import java.sql.Statement;
 import java.util.Date;
 
-import org.sqlite.date.FastDateFormat;
-
-import org.junit.BeforeClass;
 import org.junit.Test;
+import org.sqlite.date.FastDateFormat;
 
 public class QueryTest
 {
@@ -103,6 +104,49 @@ public void dateTimeTest() throws Exception {
         stmt.setDate(1, new java.sql.Date(now.getTime()));
     }
 
+    @Test
+    public void notEmptyBlob() throws Exception {
+        Connection conn = getConnection();
+
+        conn.createStatement().execute("create table sample (b blob not null)");
+
+        conn.createStatement().execute("insert into sample values(zeroblob(5))");
+
+        ResultSet rs = conn.createStatement().executeQuery("select * from sample");
+        assertTrue(rs.next());
+        assertEquals(5, rs.getBytes(1).length);
+        assertFalse(rs.wasNull());
+    }
+
+    @Test
+    public void emptyBlob() throws Exception {
+        Connection conn = getConnection();
+
+        conn.createStatement().execute("create table sample (b blob null)");
+
+        conn.createStatement().execute("insert into sample values(zeroblob(0))");
+
+        ResultSet rs = conn.createStatement().executeQuery("select * from sample");
+        assertTrue(rs.next());
+        assertEquals(0, rs.getBytes(1).length);
+        assertFalse(rs.wasNull());
+    }
+
+    @Test
+    public void nullBlob() throws Exception {
+        Connection conn = getConnection();
+
+        conn.createStatement().execute("create table sample (b blob null)");
+
+        conn.createStatement().execute("insert into sample values(null)");
+
+        ResultSet rs = conn.createStatement().executeQuery("select * from sample");
+        assertTrue(rs.next());
+        assertNull(rs.getBytes(1));
+        assertTrue(rs.wasNull());
+    }
+
+
     @Test
     public void viewTest() throws Exception {
         Connection conn = getConnection();