Simplify permission checking in template

Consistenly use can_translate helper to check whether user is allowed to
translate given translation.
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/html/last-changes.html

 {% load i18n %}
 {% load translations %}
+{% load permissions %}
+
 <div class="panel panel-primary">
 <div class="panel-heading">
 <h4 class="panel-title">{% if history_title %}{{ history_title }}{% else %}{% trans "History" %}{% endif %}</h4>
@@ -29,11 +31,10 @@
 <tr>
 <td colspan="4">{% format_translation c.target c.unit.translation.language %}</td>
 <td>
-{% if perms.trans.save_translation and c.target != c.unit.target %}
-{% if perms.trans.save_template or not trans.is_template %}
+{% can_translate request.user c.translation as user_can_translate %}
+{% if user_can_translate %}
 <a class="historybutton small-button" href="{{ c.translation.get_translate_url}}?{% if search_id %}sid={{ search_id }}&amp;offset={{ offset }}&amp;{% endif %}checksum={{ c.unit.checksum }}&amp;revert={{ c.id }}" title="{% trans "Revert to this translation" %}">{% trans "Revert" %}</a>
 {% endif %}
-{% endif %}
 </td>
 </tr>
 {% elif c.target %}

weblate/html/translate.html

@@ -3,6 +3,9 @@
 {% load static %}
 {% load translations %}
 {% load crispy_forms_tags %}
+{% load permissions %}
+{% can_translate request.user unit.translation as user_can_translate %}
+
 
 {% block extra_meta %}
 <link rel="canonical" href="{{ unit.get_absolute_url }}" />
@@ -17,11 +20,9 @@
 
 {% block content %}
 
-{% if perms.trans.save_translation %}
-{% if perms.trans.save_template or not object.is_template %}
+{% if user_can_translate %}
 <a href="{% url 'zen' project=unit.translation.subproject.project.slug subproject=unit.translation.subproject.slug lang=unit.translation.language.code %}?sid={{ search_id }}" title="{% trans "Edit in Zen mode" %}" class="btn btn-default pull-right flip"><i class="fa fa-arrows-alt"></i> {% trans "Zen" %}</a>
 {% endif %}
-{% endif %}
 
 {% with unit.translation as object %}
 {% include "show-lock.html" %}
@@ -84,18 +85,14 @@
     {{ form|crispy }}
   </div>
   <div class="panel-footer">
-    {% if not unit.translation.only_vote_suggestions or perms.trans.override_suggestion %}
-    {% if perms.trans.save_translation %}
-    {% if perms.trans.save_template or not object.is_template %}
+    {% if user_can_translate %}
     <input class="btn btn-default" type="submit" value="{% trans "Save" %}" name="save" tabindex="150" {% if locked %}disabled="disabled"{% endif %} />
-    {% endif %}
     {% elif not user.is_authenticated %}
     {% url 'login' as login_url %}
     {% with unit.translation.get_translate_url as translate_url %}
     {% blocktrans %}<a href="{{ login_url }}?next={{ translate_url }}">Log in</a> for saving translations.{% endblocktrans %}
     {% endwith %}
     {% endif %}
-    {% endif %}
 
     {% if unit.translation.subproject.enable_suggestions %}
     {% if perms.trans.add_suggestion %}
@@ -105,8 +102,7 @@
     {% endif %}
     {% endif %}
 
-    {% if perms.trans.save_translation %}
-    {% if perms.trans.save_template or not object.is_template %}
+    {% if user_can_translate %}
     <div class="pull-right flip hidden-xs">
     {% trans "Commit message:" %} 
     <input type="text" name="commit_message" class="tooltip-control" 
@@ -118,7 +114,6 @@
     />
     </div>
     {% endif %}
-    {% endif %}
   </div>
 </div>
 </form>
@@ -229,11 +224,9 @@
     <td><a href="{{ item.get_absolute_url }}">{% format_translation item.target item.translation.language unit.target %}</a></td>
     <td>{% get_state_flags item %}</td>
     <td>
-    {% if perms.trans.save_translation %}
-    {% if perms.trans.save_template or not object.is_template %}
+    {% if user_can_translate %}
     <a class="mergebutton small-button btn btn-default" href="{{ unit.translation.get_translate_url}}?sid={{ search_id }}&amp;offset={{ offset }}&amp;checksum={{ unit.checksum }}&amp;merge={{ item.id }}" title="{% trans "Use this translation for all components" %}">{% trans "Use this translation" %}</a>
     {% endif %}
-    {% endif %}
     </td>
     </tr>
     {% endfor %}
@@ -369,11 +362,9 @@
         <td>{{ item.source }}</td>
         <td class="target">{% format_translation item.target unit.translation.language simple=True %}</td>
         <td>
-        {% if perms.trans.save_translation %}
-        {% if perms.trans.save_template or not object.is_template %}
+        {% if user_can_translate or perms.trans.add_suggestion %}
         <a class="copydict btn btn-default btn-xs" title="{% trans "Copy word to translation" %}">{% trans "Copy" %}</a>
         {% endif %}
-        {% endif %}
         </td>
         </tr>
     {% endfor %}

weblate/trans/templatetags/permissions.py

+# -*- coding: utf-8 -*-
+#
+# Copyright © 2012 - 2015 Michal Čihař <michal@cihar.com>
+#
+# This file is part of Weblate <http://weblate.org/>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+from django import template
+import weblate.trans.permissions
+
+register = template.Library()
+
+
+@register.assignment_tag
+def can_translate(user, translation):
+    return weblate.trans.permissions.can_translate(
+        user, translation
+    )