pad.html: UI telling the user that a contribution is required before importing

This commit is an integration to 24ee37a38f.

src/static/css/pad.css

@@ -70,4 +70,8 @@ input {
 
 @media (max-width: 800px) {
   .hide-for-mobile { display: none; }
-}
+}
+
+#importmessagepermission {
+  display: none;
+}

src/static/js/collab_client.js

@@ -313,6 +313,16 @@ function getCollabClient(ace2editor, serverVars, initialUserInfo, options, _pad)
     }
     else if (msg.type == "ACCEPT_COMMIT")
     {
+      /*
+       * this is the first time this user contributed to this pad. Let's record
+       * it, because it will be used for allowing import.
+       *
+       * TODO: here, we are changing this variable on the client side only. The
+       *       server has all the informations to make the same deduction, and
+       *       broadcast to the client.
+       */
+      clientVars.thisUserHasEditedThisPad = true;
+
       var newRev = msg.newRev;
       if (msgQueue.length > 0)
       {

src/static/js/pad_editbar.js

@@ -394,6 +394,17 @@ var padeditbar = (function()
 
     toolbar.registerCommand("import_export", function () {
       toolbar.toggleDropDown("import_export", function(){
+
+        if (clientVars.thisUserHasEditedThisPad) {
+          // the user has edited this pad historically or in this session
+          $('#importform').show();
+          $('#importmessagepermission').hide();
+        } else {
+          // this is the first time this user visits this pad
+          $('#importform').hide();
+          $('#importmessagepermission').show();
+        }
+
         // If Import file input exists then focus on it..
         if($('#importfileinput').length !== 0){
           setTimeout(function(){

src/static/js/pad_impexp.js

@@ -113,6 +113,8 @@ var padimpexp = (function()
       msg = html10n.get("pad.impexp.padHasData");
     } else if(status === "maxFileSize"){
       msg = html10n.get("pad.impexp.maxFileSize");
+    } else if(status === "permission"){
+      msg = html10n.get("pad.impexp.permission");
     }
 
     function showError(fade)