corrected bug preventing to download slice of attachment in indexeddbstorage

added test verifying that the bug is corrected.

src/jio.storage/indexeddbstorage.js

@@ -350,6 +350,7 @@
         var array_buffer_list = [],
           blob,
           i,
+          index,
           len = result_list.length;
         for (i = 0; i < len; i += 1) {
           array_buffer_list.push(result_list[i].blob);
@@ -357,8 +358,10 @@
         if ((options.start === undefined) && (options.end === undefined)) {
           return new Blob(array_buffer_list, {type: type});
         }
+        index = Math.floor(start / UNITE) * UNITE;
         blob = new Blob(array_buffer_list, {type: "application/octet-stream"});
-        return blob.slice(start, end, "application/octet-stream");
+        return blob.slice(start - index, end - index,
+                          "application/octet-stream");
       });
   };
 

test/jio.storage/indexeddbstorage.tests.js

@@ -1319,6 +1319,38 @@
       });
   });
 
+  test("retrieving slice of data", function () {
+    var context = this,
+      attachment = "attachment";
+    stop();
+    expect(1);
+
+    deleteIndexedDB(context.jio)
+      .then(function () {
+        return context.jio.put("foo", {"title": "bar"});
+      })
+      .then(function () {
+        return context.jio.putAttachment("foo", attachment, big_string);
+      })
+      .then(function () {
+        return context.jio.getAttachment("foo", attachment,
+                                         {"start": 2000005, "end": 2000015});
+      })
+      .then(function (result) {
+        return jIO.util.readBlobAsText(result);
+      })
+      .then(function (result) {
+        var expected = "aaaaaaaaaa";
+        equal(result.target.result, expected, "Attachment correctly fetched");
+      })
+      .fail(function (error) {
+        ok(false, error);
+      })
+      .always(function () {
+        start();
+      });
+  });
+
   /////////////////////////////////////////////////////////////////
   // indexeddbStorage.removeAttachment
   /////////////////////////////////////////////////////////////////