Merge pull request #175 from gwenn/empty-blob

Empty blob

src/lib.rs

@@ -1123,12 +1123,17 @@ impl<'a> ValueRef<'a> {
             }
             ffi::SQLITE_BLOB => {
                 let blob = ffi::sqlite3_column_blob(raw, col);
-                assert!(!blob.is_null(), "unexpected SQLITE_BLOB column type with NULL data");
 
                 let len = ffi::sqlite3_column_bytes(raw, col);
                 assert!(len >= 0, "unexpected negative return from sqlite3_column_bytes");
+                if len > 0 {
+                    assert!(!blob.is_null(), "unexpected SQLITE_BLOB column type with NULL data");
+                    ValueRef::Blob(from_raw_parts(blob as *const u8, len as usize))
+                } else {
+                    // The return value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
+                    ValueRef::Blob(&[])
+                }
 
-                ValueRef::Blob(from_raw_parts(blob as *const u8, len as usize))
             }
             _ => unreachable!("sqlite3_column_type returned invalid value")
         }

src/types/mod.rs

@@ -129,6 +129,17 @@ mod test {
         assert_eq!(v, v1234);
     }
 
+    #[test]
+    fn test_empty_blob() {
+        let db = checked_memory_handle();
+
+        let empty = vec![];
+        db.execute("INSERT INTO foo(b) VALUES (?)", &[&empty]).unwrap();
+
+        let v: Vec<u8> = db.query_row("SELECT b FROM foo", &[], |r| r.get(0)).unwrap();
+        assert_eq!(v, empty);
+    }
+
     #[test]
     fn test_str() {
         let db = checked_memory_handle();