[gparted/ro-mount: 1/5] Add read-only flag to mounted file system entries (#10)

[Mike Fleetwood <mfleetwo src gnome org>]

commit 324872c5fe1781382d7446db8ed85ae55e71d020
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Mon Sep 17 11:08:31 2018 +0100

    Add read-only flag to mounted file system entries (#10)
    
    Just updates the 2 maps in the Mount_Info module so that they also have
    a read-only flag for each mount.  Ensure that when a struct MountEntry
    is created the readonly bool POD (Plain Old Data) type is initialised by
    the constructor.  Nothing yet sets or uses the flag.
    
    Closes #10 - Gparted fails to resize btrfs partition that is mounted
                 read-only

 include/Mount_Info.h | 12 ++++++++++--
 src/Mount_Info.cc    | 41 +++++++++++++++++++++++------------------
 2 files changed, 33 insertions(+), 20 deletions(-)
---
diff --git a/include/Mount_Info.h b/include/Mount_Info.h
index 6ef411ed..b37395ae 100644
--- a/include/Mount_Info.h
+++ b/include/Mount_Info.h
@@ -33,10 +33,18 @@
 namespace GParted
 {
 
+struct MountEntry
+{
+       bool                       readonly;     // Is the file system mounted read-only?
+       std::vector<Glib::ustring> mountpoints;  // File system mounted on ...
+
+       MountEntry() : readonly( false )  {};
+};
+
 class Mount_Info
 {
 public:
-       typedef std::map<BlockSpecial, std::vector<Glib::ustring> > MountMapping;
+       typedef std::map<BlockSpecial, MountEntry> MountMapping;
 
        static void load_cache();
        static bool is_dev_mounted( const Glib::ustring & path );
@@ -54,7 +62,7 @@ private:
                                                      MountMapping & map );
        static bool have_rootfs_dev( MountMapping & map );
        static void read_mountpoints_from_mount_command( MountMapping & map );
-       static const std::vector<Glib::ustring> & find( const MountMapping & map, const Glib::ustring & path 
);
+       static const MountEntry & find( const MountMapping & map, const Glib::ustring & path );
 };
 
 } //GParted
diff --git a/src/Mount_Info.cc b/src/Mount_Info.cc
index b26b1c2b..8196baea 100644
--- a/src/Mount_Info.cc
+++ b/src/Mount_Info.cc
@@ -31,15 +31,17 @@ namespace GParted
 
 // Associative array mapping currently mounted devices to one or more mount points.
 // E.g.
-//     mount_info[BlockSpecial("/dev/sda1")] -> ["/boot"]
-//     mount_info[BlockSpecial("/dev/sda2")] -> [""]  (swap)
-//     mount_info[BlockSpecial("/dev/sda3")] -> ["/"]
+//     //                                         readonly, mountpoints
+//     mount_info[BlockSpecial("/dev/sda1")] -> {false   , ["/boot"]}
+//     mount_info[BlockSpecial("/dev/sda2")] -> {false   , [""]     }  // swap
+//     mount_info[BlockSpecial("/dev/sda3")] -> {false   , ["/"]    }
 static Mount_Info::MountMapping mount_info;
 
 // Associative array mapping configured devices to one or more mount points read from
 // /etc/fstab.  E.g.
-//     fstab_info[BlockSpecial("/dev/sda1")] -> ["/boot"]
-//     fstab_info[BlockSpecial("/dev/sda3")] -> ["/"]
+//     //                                        readonly, mountpoints
+//     fstab_info[BlockSpecial("/dev/sda1")] -> {false   ,["/boot"]}
+//     fstab_info[BlockSpecial("/dev/sda3")] -> {false   ,["/"]    }
 static Mount_Info::MountMapping fstab_info;
 
 void Mount_Info::load_cache()
@@ -69,11 +71,11 @@ void Mount_Info::load_cache()
        MountMapping::iterator iter_mp;
        for ( iter_mp = mount_info.begin() ; iter_mp != mount_info.end() ; ++ iter_mp )
        {
-               std::sort( iter_mp->second.begin(), iter_mp->second.end() );
+               std::sort( iter_mp->second.mountpoints.begin(), iter_mp->second.mountpoints.end() );
 
-               iter_mp->second.erase(
-                               std::unique( iter_mp->second.begin(), iter_mp->second.end() ),
-                               iter_mp->second.end() );
+               iter_mp->second.mountpoints.erase(
+                               std::unique( iter_mp->second.mountpoints.begin(), 
iter_mp->second.mountpoints.end() ),
+                               iter_mp->second.mountpoints.end() );
        }
 }
 
@@ -96,19 +98,20 @@ std::vector<Glib::ustring> Mount_Info::get_all_mountpoints()
        std::vector<Glib::ustring> mountpoints;
 
        for ( iter_mp = mount_info.begin() ; iter_mp != mount_info.end() ; ++ iter_mp )
-               mountpoints.insert( mountpoints.end(), iter_mp->second.begin(), iter_mp->second.end() );
+               mountpoints.insert( mountpoints.end(),
+                                   iter_mp->second.mountpoints.begin(), iter_mp->second.mountpoints.end() );
 
        return mountpoints;
 }
 
 const std::vector<Glib::ustring> & Mount_Info::get_mounted_mountpoints( const Glib::ustring & path )
 {
-       return find( mount_info, path );
+       return find( mount_info, path ).mountpoints;
 }
 
 const std::vector<Glib::ustring> & Mount_Info::get_fstab_mountpoints( const Glib::ustring & path )
 {
-       return find( fstab_info, path );
+       return find( fstab_info, path ).mountpoints;
 }
 
 // Private methods
@@ -146,7 +149,8 @@ void Mount_Info::add_node_and_mountpoint( MountMapping & map,
 {
        // Only add node path if mount point exists
        if ( file_test( mountpoint, Glib::FILE_TEST_EXISTS ) )
-               map[BlockSpecial( node )].push_back( mountpoint );
+               // Map::operator[] default constructs MountEntry for new keys (nodes).
+               map[BlockSpecial( node )].mountpoints.push_back( mountpoint );
 }
 
 void Mount_Info::read_mountpoints_from_file_swaps( const Glib::ustring & filename, MountMapping & map )
@@ -161,7 +165,7 @@ void Mount_Info::read_mountpoints_from_file_swaps( const Glib::ustring & filenam
                {
                        node = Utils::regexp_label( line, "^(/[^ ]+)" );
                        if ( node.size() > 0 )
-                               map[BlockSpecial( node )].push_back( "" /* no mountpoint for swap */ );
+                               map[BlockSpecial( node )].mountpoints.push_back( "" /* no mountpoint for swap 
*/ );
                }
                file.close();
        }
@@ -174,7 +178,7 @@ bool Mount_Info::have_rootfs_dev( MountMapping & map )
        MountMapping::const_iterator iter_mp;
        for ( iter_mp = mount_info.begin() ; iter_mp != mount_info.end() ; iter_mp ++ )
        {
-               if ( ! iter_mp->second.empty() && iter_mp->second[0] == "/" )
+               if ( ! iter_mp->second.mountpoints.empty() && iter_mp->second.mountpoints[0] == "/" )
                {
                        if ( iter_mp->first.m_name != "rootfs" && iter_mp->first.m_name != "/dev/root" )
                                return true;
@@ -202,13 +206,14 @@ void Mount_Info::read_mountpoints_from_mount_command( MountMapping & map )
        }
 }
 
-const std::vector<Glib::ustring> & Mount_Info::find( const MountMapping & map, const Glib::ustring & path )
+const MountEntry & Mount_Info::find( const MountMapping & map, const Glib::ustring & path )
 {
        MountMapping::const_iterator iter_mp = map.find( BlockSpecial( path ) );
        if ( iter_mp != map.end() )
                return iter_mp->second;
 
-       static std::vector<Glib::ustring> empty;
-       return empty;
+       static MountEntry not_mounted = MountEntry();
+       return not_mounted;
 }
+
 } //GParted