rebaseline_server: add urlSchemaVersion parameter

In https://codereview.chromium.org/369473005 ('rebaseline_server: handle category filtering more generically'), I am changing the meaning of some URL parameters.  If a user pastes an old URL into an updated rebaseline_server instance, they may get unexpected results.  Adding a urlSchemaVersion parameter allows us to automatically convert the URL, or at least warn the user.

BUG=skia:2230
NOTRY=True
R=jcgregorio@google.com

Author: epoger@google.com

Review URL: https://codereview.chromium.org/368933002

3 files changed, 24 insertions, 0 deletions

diff --git a/gm/rebaseline_server/static/constants.js b/gm/rebaseline_server/static/constants.js
index 7db245daf0..55751d1e21 100644
--- a/gm/rebaseline_server/static/constants.js
+++ b/gm/rebaseline_server/static/constants.js
@@ -73,6 +73,11 @@ module.constant('constants', (function() {
     KEY__EDITS__MODIFICATIONS: 'modifications',
     KEY__EDITS__OLD_RESULTS_HASH: 'oldResultsHash',
     KEY__EDITS__OLD_RESULTS_TYPE: 'oldResultsType',
+    URL_KEY__SCHEMA_VERSION: 'urlSchemaVersion',
+    URL_VALUE__SCHEMA_VERSION__CURRENT: 0,
+    // always interpret as then-current schema version;
+    // used for toplevel links on index page
+    URL_VALUE__SCHEMA_VERSION__ALWAYS_CURRENT: 'current',
 
     // These are just used on the client side, no need to sync with server code.
     KEY__IMAGEPAIRS__ROWSPAN: 'rowspan',
diff --git a/gm/rebaseline_server/static/loader.js b/gm/rebaseline_server/static/loader.js
index 296689bde2..dbded05f25 100644
--- a/gm/rebaseline_server/static/loader.js
+++ b/gm/rebaseline_server/static/loader.js
@@ -426,6 +426,16 @@ Loader.controller(
     // any which are not found within the URL will keep their current value.
     $scope.queryParameters.load = function() {
       var nameValuePairs = $location.search();
+
+      var urlSchemaVersion = nameValuePairs[constants.URL_KEY__SCHEMA_VERSION];
+      if (!urlSchemaVersion) {
+        $scope.urlSchemaVersionLoaded = 0;
+      } else if (urlSchemaVersion == constants.URL_VALUE__SCHEMA_VERSION__ALWAYS_CURRENT) {
+        $scope.urlSchemaVersionLoaded = constants.URL_VALUE__SCHEMA_VERSION__CURRENT;
+      } else {
+        $scope.urlSchemaVersionLoaded = urlSchemaVersion;
+      }
+
       angular.forEach($scope.queryParameters.map,
                       function(copier, paramName) {
                         copier.load(nameValuePairs, paramName);
@@ -436,6 +446,7 @@ Loader.controller(
     // Saves all parameters from $scope into the URL query string.
     $scope.queryParameters.save = function() {
       var nameValuePairs = {};
+      nameValuePairs[constants.URL_KEY__SCHEMA_VERSION] = constants.URL_VALUE__SCHEMA_VERSION__CURRENT;
       angular.forEach($scope.queryParameters.map,
                       function(copier, paramName) {
                         copier.save(nameValuePairs, paramName);
diff --git a/gm/rebaseline_server/static/view.html b/gm/rebaseline_server/static/view.html
index fda767c5b4..94dc9ba63e 100644
--- a/gm/rebaseline_server/static/view.html
+++ b/gm/rebaseline_server/static/view.html
@@ -26,6 +26,14 @@
   <div ng-show="extraColumnHeaders"><!-- everything: hide until data is loaded -->
 
     <div class="warning-div"
+         ng-show="urlSchemaVersionLoaded != constants.URL_VALUE__SCHEMA_VERSION__CURRENT">
+      WARNING!  The URL you loaded used schema version {{urlSchemaVersionLoaded}}, rather than
+      the most recent version {{constants.URL_VALUE__SCHEMA_VERSION__CURRENT}}.  It has been
+      converted to the most recent version on a best-effort basis; you may wish to double-check
+      which records are displayed.
+    </div>
+
+    <div class="warning-div"
          ng-show="header[constants.KEY__HEADER__IS_EDITABLE] && header[constants.KEY__HEADER__IS_EXPORTED]">
       WARNING!  These results are editable and exported, so any user
       who can connect to this server over the network can modify them.