[gparted] Add reporting of linux-swap usage (#708107)

[Curtis Gedak <gedakc src gnome org>]

commit 387b391d6dd2b8d02807a20800fff78da673fd60
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Sat Sep 14 14:51:16 2013 +0100

    Add reporting of linux-swap usage (#708107)
    
    For active swap space read the usage from /proc/swaps.  (Linux kernel
    uses units of 1 KiB).  By definition inactive swap space is 100% free.
    
        $ cat /proc/swaps
        Filename                                Type            Size    Used    Priority
        /dev/sda2                               partition       5242876 430552  -1
    
    Always set fs.read = FS::EXTERNAL even if /proc/swaps doesn't exist so
    that an attempt is made to open the file generating a specific error, in
    addition to the generic error.
    
        open("/proc/swaps", O_RDONLY): No such file or directory
    
        Unable to read the contents of this file system!
        Because of this some operations may be unavailable.
    
        The cause might be a missing software package.
        The following list of software packages is required for linux-
        swap file system support: util-linux.
    
    Closes Bug #708107 - Usage of swap space is not reported

 include/linux_swap.h |    1 +
 src/GParted_Core.cc  |    3 +--
 src/linux_swap.cc    |   45 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 2 deletions(-)
---
diff --git a/include/linux_swap.h b/include/linux_swap.h
index 1b3e485..d1ab283 100644
--- a/include/linux_swap.h
+++ b/include/linux_swap.h
@@ -31,6 +31,7 @@ public:
        virtual const Glib::ustring get_custom_text( CUSTOM_TEXT ttype, int index = 0 ) ;
 
        FS get_filesystem_support() ;
+       void set_used_sectors( Partition & partition ) ;
        void read_label( Partition & partition ) ;
        bool write_label( const Partition & partition, OperationDetail & operationdetail ) ;
        void read_uuid( Partition & partition ) ;
diff --git a/src/GParted_Core.cc b/src/GParted_Core.cc
index d534f14..6c1c8a5 100644
--- a/src/GParted_Core.cc
+++ b/src/GParted_Core.cc
@@ -1539,8 +1539,7 @@ void GParted_Core::set_used_sectors( std::vector<Partition> & partitions, PedDis
 {
        for ( unsigned int t = 0 ; t < partitions .size() ; t++ )
        {
-               if ( partitions[ t ] .filesystem != GParted::FS_LINUX_SWAP &&
-                    partitions[ t ] .filesystem != GParted::FS_LUKS       &&
+               if ( partitions[ t ] .filesystem != GParted::FS_LUKS       &&
                     partitions[ t ] .filesystem != GParted::FS_UNKNOWN
                   )
                {
diff --git a/src/linux_swap.cc b/src/linux_swap.cc
index 01d4872..0ad3ea2 100644
--- a/src/linux_swap.cc
+++ b/src/linux_swap.cc
@@ -19,6 +19,8 @@
  
 #include "../include/linux_swap.h"
 
+#include <cerrno>
+
 namespace GParted
 {
 
@@ -43,6 +45,9 @@ FS linux_swap::get_filesystem_support()
        FS fs ;
        fs .filesystem = GParted::FS_LINUX_SWAP ;
        
+       fs .read = FS::EXTERNAL ;
+       fs .online_read = FS::EXTERNAL ;
+
        if ( ! Glib::find_program_in_path( "mkswap" ) .empty() )
        {
                fs .create = GParted::FS::EXTERNAL ;
@@ -65,6 +70,46 @@ FS linux_swap::get_filesystem_support()
        return fs ;
 }
 
+void linux_swap::set_used_sectors( Partition & partition )
+{
+       if ( partition .busy )
+       {
+               T = -1 ; N = -1 ;
+               std::string line ;
+               std::ifstream input( "/proc/swaps" ) ;
+               if ( input )
+               {
+                       Glib::ustring path = partition .get_path() ;
+                       Glib::ustring::size_type path_len = path.length() ;
+                       while ( getline( input, line ) )
+                       {
+                               if ( line .substr( 0, path_len ) == path )
+                               {
+                                       sscanf( line .substr( path_len ) .c_str(), " %*s %Ld %Ld", &T, &N ) ;
+                                       break ;
+                               }
+                       }
+                       input .close() ;
+               }
+               else
+               {
+                       partition .messages .push_back( "open(\"/proc/swaps\", O_RDONLY): " + Glib::strerror( 
errno ) ) ;
+               }
+               if ( T > -1 && N > -1 )
+               {
+                       T = Utils::round( T * ( KIBIBYTE / double(partition .sector_size) ) ) ;
+                       N = Utils::round( N * ( KIBIBYTE / double(partition .sector_size) ) ) ;
+                       partition .set_sector_usage( T, T - N ) ;
+               }
+       }
+       else
+       {
+               //By definition inactive swap space is 100% free
+               Sector size = partition .get_sector_length() ;
+               partition .set_sector_usage( size, size ) ;
+       }
+}
+
 void linux_swap::read_label( Partition & partition )
 {
        if ( ! Utils::execute_command( "swaplabel " + partition .get_path(), output, error, true ) )