[indexeddb] Fix getAttachment with huge blob

The array buffer length was higher than what is stored in indexedDB

Thanks to Alexandra Rogova for reporting the issue.

src/jio.storage/indexeddbstorage.js

@@ -474,8 +474,7 @@
                   var index = parseInt(
                     cursor.primaryKey.slice(key_path.length + 1),
                     10
-                  ),
-                    i;
+                  );
 
                   if ((start !== 0) && (index < start_index)) {
                     // No need to fetch blobs at the start
@@ -486,12 +485,6 @@
                     return;
                   }
 
-                  i = index - start_index;
-                  // Extend array size
-                  while (i > promise_list.length) {
-                    promise_list.push(null);
-                    i -= 1;
-                  }
                   // Sort the blob by their index
                   promise_list.splice(
                     index - start_index,
@@ -548,13 +541,8 @@
                 var index = parseInt(
                   cursor.primaryKey.slice(key_path.length + 1),
                   10
-                ),
-                  i = index;
-                // Extend array size
-                while (i > array_buffer_list.length) {
-                  array_buffer_list.push(null);
-                  i -= 1;
-                }
+                );
+
                 // Sort the blob by their index
                 array_buffer_list.splice(
                   index,

test/jio.storage/indexeddbstorage.tests.js

@@ -20,10 +20,10 @@
 /*jslint nomen: true */
 /*global indexedDB, Blob, sinon, IDBDatabase,
          IDBTransaction, IDBIndex, IDBObjectStore, IDBCursor, IDBKeyRange,
-         DOMException*/
+         DOMException, Rusha*/
 (function (jIO, QUnit, indexedDB, Blob, sinon, IDBDatabase,
            IDBTransaction, IDBIndex, IDBObjectStore, IDBCursor, IDBKeyRange,
-           DOMException) {
+           DOMException, Rusha) {
   "use strict";
   var test = QUnit.test,
     stop = QUnit.stop,
@@ -34,12 +34,9 @@
     equal = QUnit.equal,
     module = QUnit.module,
     throws = QUnit.throws,
-    big_string = "",
-    j;
+    big_string = "";
 
-  for (j = 0; j < 3000000; j += 1) {
-    big_string += "a";
-  }
+  big_string = new Array(3000000).fill('a').join('');
 
   function deleteIndexedDB(storage) {
     return new RSVP.Promise(function resolver(resolve, reject) {
@@ -1692,6 +1689,46 @@
       });
   });
 
+
+  test("get huge attachment", function () {
+    var context = this,
+      attachment = "attachment";
+    stop();
+    expect(4);
+
+    deleteIndexedDB(context.jio)
+      .then(function () {
+        return context.jio.put("foo", {"title": "bar"});
+      })
+      .then(function () {
+        return context.jio.putAttachment(
+          "foo",
+          attachment,
+          new Blob([new Array(11 * 2000000).fill('a').join('')],
+                   {type: 'text/fooplain'})
+        );
+      })
+      .then(function () {
+        return context.jio.getAttachment("foo", attachment);
+      })
+      .then(function (blob) {
+        ok(blob instanceof Blob, "Data is Blob");
+        equal(blob.type, 'text/fooplain');
+        equal(blob.size, 22000000);
+        return jIO.util.readBlobAsArrayBuffer(blob);
+      })
+      .then(function (result) {
+        equal((new Rusha()).digestFromArrayBuffer(result.target.result),
+              '6f510194afd8e436d00a543f49a7df09e86c2687');
+      })
+      .fail(function (error) {
+        ok(false, error);
+      })
+      .always(function () {
+        start();
+      });
+  });
+
   test("retrieve empty blob", function () {
     var context = this,
       attachment = "attachment",
@@ -2017,4 +2054,4 @@
 
 }(jIO, QUnit, indexedDB, Blob, sinon, IDBDatabase,
   IDBTransaction, IDBIndex, IDBObjectStore, IDBCursor, IDBKeyRange,
-  DOMException));
+  DOMException, Rusha));