[FIX] mitigate horrendous performance issues inserting options in Webkit

In some cases, at least with complex-enough views, inserting many
options in a document in a row will get progressively slower.

In import, this issue is hit on trying to import partners: partners
have a humongous number of fields (direct and on their o2m), ~940,
which yields a correspondingly huge number of options in the
selection.

A basic partner export also has quite high a number of columns (~50
without exporting o2m fields), so this list of 940 options is inserted
50 times in a row (literally too, they're all in the same table row)..

While not all that fast, Firefox 5/6 has no significant issue with
this (~18ms/insertion, where an insertion is a full select with all
its options). Webkit browsers (Chrome and Safari) on the other hand
start out fair (~10ms/insertion), but get slower and slower until they
end up at 3~5 *seconds* for each insertion (3s if inserting a
DocumentFragment, 5s if inserting text via innerHTML). This means the
preview table takes up to *two minutes* to display, even the best
cases (pre-generating everything that can be and optimizing everything
I could think of) take 75 *seconds* for the insertions (the
pregeneration of a given select and its options is ~100ms, the base
template rendering is ~20ms).

rendering divs or inputs does not have this issue, I did not manage to
reduce or fix the issue directly so I replaced the options by
jQuery-ui's autocomplete widget. This is not issues-free: when tabbing
through the fields lists, when reaching the edge of the popup the
browser will automatically scroll the field back into view. However,
this is done *after* autocomplete's popup has opened, and as a result
the popup opens in the wrong place (at the popup's edge, instead of
under the now-moved field).

bzr revid: xmo@openerp.com-20110922085812-3u1esk6czraskm01

1 files changed, 12 insertions, 18 deletions

diff --git a/addons/web/static/src/xml/base.xml b/addons/web/static/src/xml/base.xml
index 09e71043e38..3245ec43e8f 100644
--- a/addons/web/static/src/xml/base.xml
+++ b/addons/web/static/src/xml/base.xml
@@ -1459,23 +1459,17 @@
         </t>
     </t>
     <table t-if="records" class="oe_import_grid" width="100%" style="margin: 5px 0;">
-        <t t-foreach="records" t-as="record">
-            <tr t-if="record=='header'" class="oe_import_grid-header">
-                <td t-foreach="records.header" t-as="header" class="oe_import_grid-cell"><t t-esc="header[0]"/></td>
-            </tr>
-            <tr t-if="record=='sel'">
-                <td t-foreach="records.header" t-as="header">
-                    <select id="sel_field" class="select_fld">
-                        <option selected="selected" value=""></option>
-                        <option t-foreach="records.sel" t-as="selection" t-att="{'selected': header[0] === selection ? 'selected' : null}"
-                                t-att-value="selection"><t t-esc="selection"/></option>
-                    </select>
-                </td>
-            </tr>
-            <tr t-if="record=='row'" t-foreach="records.row" t-as="row" class="oe_import_grid-row">
-                <td t-foreach="row" t-as="column" class="oe_import_grid-cell"><t t-esc="column"/></td>
-            </tr>
-        </t>
+        <tr class="oe_import_grid-header">
+            <td t-foreach="records.header" t-as="header" class="oe_import_grid-cell"><t t-esc="header[0]"/></td>
+        </tr>
+        <tr>
+            <td t-foreach="records.header" t-as="header">
+                <input class="sel_fields"/>
+            </td>
+        </tr>
+        <tr t-foreach="records.row" t-as="row" class="oe_import_grid-row">
+            <td t-foreach="row" t-as="column" class="oe_import_grid-cell"><t t-esc="column"/></td>
+        </tr>
     </table>
 </t>
 
@@ -1522,4 +1516,4 @@
 <t t-name="EmptyComponent">
     <div></div>
 </t>
-</templates>
\ No newline at end of file
+</templates>