Add sort criterion by reversed extension segments

The basenames of files are split by dots and then starting from the end
each segment is compared to find a sort order. Example:

    bar.tar.bz2
    foo.tar.bz2
    a.bar.gz
    x.tar.gz
    z.tar.gz
    test.tex

A heuristic determines what extension segments are part of the
extension. There is probably no perfect solution but there are much
less false positives. As a result the sorting is more intuitive and the
displayed column in the list view is better readable and displays
extensions more accurately.

In addition a bug related to the default sort criteria in the
preferences has been fixed.

4 files changed, 28 insertions, 0 deletions

diff --git a/src/caja-file-management-properties.c b/src/caja-file-management-properties.c
index dc687688..0568f360 100644
--- a/src/caja-file-management-properties.c
+++ b/src/caja-file-management-properties.c
@@ -94,6 +94,12 @@ static const char * const zoom_values[] =
     NULL
 };
 
+/*
+ * This array corresponds to the object with id "model2" in
+ * caja-file-management-properties.ui. It has to positionally match with it.
+ * The purpose is to map values from a combo box to values of the gsettings
+ * enum.
+ */
 static const char * const sort_order_values[] =
 {
     "name",
@@ -104,6 +110,7 @@ static const char * const sort_order_values[] =
     "mtime",
     "atime",
     "emblems",
+    "extension",
     "trash-time",
     NULL
 };
diff --git a/src/caja-file-management-properties.ui b/src/caja-file-management-properties.ui
index 4bb397ea..20d36c08 100644
--- a/src/caja-file-management-properties.ui
+++ b/src/caja-file-management-properties.ui
@@ -84,6 +84,9 @@
         <col id="0" translatable="yes">By Size</col>
       </row>
       <row>
+        <col id="0" translatable="yes">By Size on Disk</col>
+      </row>
+      <row>
         <col id="0" translatable="yes">By Type</col>
       </row>
       <row>
@@ -96,6 +99,9 @@
         <col id="0" translatable="yes">By Emblems</col>
       </row>
       <row>
+        <col id="0" translatable="yes">By Extension</col>
+      </row>
+      <row>
         <col id="0" translatable="yes">By Trashed Date</col>
       </row>
     </data>
diff --git a/src/file-manager/caja-icon-view-ui.xml b/src/file-manager/caja-icon-view-ui.xml
index 89c4cb6e..865daaf3 100644
--- a/src/file-manager/caja-icon-view-ui.xml
+++ b/src/file-manager/caja-icon-view-ui.xml
@@ -17,6 +17,7 @@
 					<menuitem name="Sort by Modification Date" action="Sort by Modification Date"/>
 					<menuitem name="Sort by Emblems" action="Sort by Emblems"/>
 					<menuitem name="Sort by Trash Time" action="Sort by Trash Time"/>
+					<menuitem name="Sort by Extension" action="Sort by Extension"/>
 				</placeholder>
 				<separator name="Layout separator"/>
 				<menuitem name="Tighter Layout" action="Tighter Layout"/>
@@ -40,6 +41,7 @@
 					<menuitem name="Sort by Modification Date" action="Sort by Modification Date"/>
 					<menuitem name="Sort by Emblems" action="Sort by Emblems"/>
 					<menuitem name="Sort by Trash Time" action="Sort by Trash Time"/>
+					<menuitem name="Sort by Extension" action="Sort by Extension"/>
 				</placeholder>
 				<separator name="Layout separator"/>
 				<menuitem name="Tighter Layout" action="Tighter Layout"/>
diff --git a/src/file-manager/fm-icon-view.c b/src/file-manager/fm-icon-view.c
index aadb3463..2d533bfc 100644
--- a/src/file-manager/fm-icon-view.c
+++ b/src/file-manager/fm-icon-view.c
@@ -169,6 +169,13 @@ static const SortCriterion sort_criteria[] =
         "Sort by Trash Time",
         N_("by T_rash Time"),
         N_("Keep icons sorted by trash time in rows")
+    },
+    {
+        CAJA_FILE_SORT_BY_EXTENSION,
+        "extension",
+        "Sort by Extension",
+        N_("by E_xtension"),
+        N_("Keep icons sorted by reversed extension segments in rows")
     }
 };
 
@@ -1770,6 +1777,12 @@ static const GtkRadioActionEntry arrange_radio_entries[] =
         N_("Keep icons sorted by trash time in rows"),
         CAJA_FILE_SORT_BY_TRASHED_TIME
     },
+    {
+        "Sort by Extension", NULL,
+        N_("By E_xtension"), NULL,
+        N_("Keep icons sorted by reverse extension segments in rows"),
+        CAJA_FILE_SORT_BY_EXTENSION
+    },
 };
 
 static void