sbuild: Move chroot-facet-union to namespace chroot::facet::fsunion

10 files changed, 522 insertions, 505 deletions

diff --git a/lib/sbuild/Makefile.am b/lib/sbuild/Makefile.am
index aadda2c9..3886338b 100644
--- a/lib/sbuild/Makefile.am
+++ b/lib/sbuild/Makefile.am
@@ -95,7 +95,7 @@ endif
 
 if BUILD_UNION
 lib_sbuild_public_union_h_sources =	\
-	lib/sbuild/chroot-facet-union.h
+	lib/sbuild/chroot/facet/fsunion.h
 endif
 
 if BUILD_UNSHARE
@@ -172,7 +172,7 @@ endif
 
 if BUILD_UNION
 lib_sbuild_public_union_cc_sources =	\
-	lib/sbuild/chroot-facet-union.cc
+	lib/sbuild/chroot/facet/fsunion.cc
 endif
 
 if BUILD_UNSHARE
diff --git a/lib/sbuild/chroot-facet-union.cc b/lib/sbuild/chroot-facet-union.cc
deleted file mode 100644
index 882737c1..00000000
--- a/lib/sbuild/chroot-facet-union.cc
+++ /dev/null
@@ -1,280 +0,0 @@
-/* Copyright © 2008-2013  Jan-Marek Glogowski <glogow@fbihome.de>
- * Copyright © 2009-2013  Roger Leigh <rleigh@debian.org>
- *
- * schroot 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.
- *
- * schroot 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/>.
- *
- *********************************************************************/
-
-#include <config.h>
-
-#include <sbuild/chroot/chroot.h>
-#include <sbuild/chroot/facet/session.h>
-#include "chroot-facet-union.h"
-#include <sbuild/chroot/facet/source-clonable.h>
-#include "feature.h"
-
-#include <cassert>
-
-using boost::format;
-using std::endl;
-using namespace sbuild;
-
-namespace
-{
-
-  sbuild::feature feature_union("UNION", N_("Support for filesystem unioning"));
-
-}
-
-template<>
-error<chroot_facet_union::error_code>::map_type
-error<chroot_facet_union::error_code>::error_strings =
-  {
-    // TRANSLATORS: %1% = chroot fs type
-    {chroot_facet_union::UNION_TYPE_UNKNOWN, N_("Unknown filesystem union type ‘%1%’")},
-    {chroot_facet_union::UNION_OVERLAY_ABS,  N_("Union overlay must have an absolute path")},
-    {chroot_facet_union::UNION_UNDERLAY_ABS, N_("Union underlay must have an absolute path")}
-  };
-
-chroot_facet_union::chroot_facet_union ():
-  chroot::facet::facet(),
-  union_type("none"),
-  union_overlay_directory(SCHROOT_OVERLAY_DIR),
-  union_underlay_directory(SCHROOT_UNDERLAY_DIR)
-{
-}
-
-chroot_facet_union::~chroot_facet_union ()
-{
-}
-
-chroot_facet_union::ptr
-chroot_facet_union::create ()
-{
-  return ptr(new chroot_facet_union());
-}
-
-chroot::facet::facet::ptr
-chroot_facet_union::clone () const
-{
-  return ptr(new chroot_facet_union(*this));
-}
-
-std::string const&
-chroot_facet_union::get_name () const
-{
-  static const std::string name("union");
-
-  return name;
-}
-
-bool
-chroot_facet_union::get_union_configured () const
-{
-  return get_union_type() != "none";
-}
-
-std::string const&
-chroot_facet_union::get_union_overlay_directory () const
-{
-  return this->union_overlay_directory;
-}
-
-void
-chroot_facet_union::set_union_overlay_directory
-(std::string const& directory)
-{
-  if (!is_absname(directory))
-    throw error(directory, UNION_OVERLAY_ABS);
-
-  this->union_overlay_directory = directory;
-}
-
-std::string const&
-chroot_facet_union::get_union_underlay_directory () const
-{
-  return this->union_underlay_directory;
-}
-
-void
-chroot_facet_union::set_union_underlay_directory
-(std::string const& directory)
-{
-  if (!is_absname(directory))
-    throw error(directory, UNION_UNDERLAY_ABS);
-
-  this->union_underlay_directory = directory;
-}
-
-std::string const&
-chroot_facet_union::get_union_type () const
-{
-  return this->union_type;
-}
-
-void
-chroot_facet_union::set_union_type (std::string const& type)
-{
-  if (type == "aufs" ||
-      type == "overlayfs" ||
-      type == "unionfs" ||
-      type == "none")
-    this->union_type = type;
-  else
-    throw error(type, UNION_TYPE_UNKNOWN);
-
-  chroot::chroot *base = dynamic_cast<chroot::chroot *>(this->owner);
-  assert(base);
-
-  if (this->union_type != "none")
-    {
-      if (!base->get_facet<chroot::facet::source_clonable>())
-        base->add_facet(chroot::facet::source_clonable::create());
-    }
-  else
-    base->remove_facet<chroot::facet::source_clonable>();
-}
-
-std::string const&
-chroot_facet_union::get_union_mount_options () const
-{
-  return union_mount_options;
-}
-
-void
-chroot_facet_union::set_union_mount_options
-(std::string const& union_mount_options)
-{
-  this->union_mount_options = union_mount_options;
-}
-
-void
-chroot_facet_union::setup_env (chroot::chroot const& chroot,
-                               environment&          env) const
-{
-  env.add("CHROOT_UNION_TYPE", get_union_type());
-  if (get_union_configured())
-    {
-      env.add("CHROOT_UNION_MOUNT_OPTIONS",
-              get_union_mount_options());
-      env.add("CHROOT_UNION_OVERLAY_DIRECTORY",
-              get_union_overlay_directory());
-      env.add("CHROOT_UNION_UNDERLAY_DIRECTORY",
-              get_union_underlay_directory());
-    }
-}
-
-chroot::chroot::session_flags
-chroot_facet_union::get_session_flags (chroot::chroot const& chroot) const
-{
-  chroot::chroot::session_flags flags = chroot::chroot::SESSION_NOFLAGS;
-
-  if (get_union_configured() && chroot.get_facet<chroot::facet::session>())
-    flags = chroot::chroot::SESSION_PURGE;
-
-  return flags;
-}
-
-void
-chroot_facet_union::get_details (chroot::chroot const& chroot,
-                                 format_detail&        detail) const
-{
-  detail.add(_("Filesystem Union Type"), get_union_type());
-  if (get_union_configured())
-    {
-      if (!this->union_mount_options.empty())
-        detail.add(_("Filesystem Union Mount Options"),
-                   get_union_mount_options());
-      if (!this->union_overlay_directory.empty())
-        detail.add(_("Filesystem Union Overlay Directory"),
-                   get_union_overlay_directory());
-      if (!this->union_underlay_directory.empty())
-        detail.add(_("Filesystem Union Underlay Directory"),
-                   get_union_underlay_directory());
-    }
-}
-
-void
-chroot_facet_union::get_used_keys (string_list& used_keys) const
-{
-  used_keys.push_back("union-type");
-  used_keys.push_back("union-mount-options");
-  used_keys.push_back("union-overlay-directory");
-  used_keys.push_back("union-underlay-directory");
-}
-
-void
-chroot_facet_union::get_keyfile (chroot::chroot const& chroot,
-                                 keyfile&              keyfile) const
-{
-  keyfile::set_object_value(*this, &chroot_facet_union::get_union_type,
-                            keyfile, chroot.get_name(), "union-type");
-
-  if (get_union_configured())
-    {
-      keyfile::set_object_value(*this,
-                                &chroot_facet_union::get_union_mount_options,
-                                keyfile, chroot.get_name(),
-                                "union-mount-options");
-
-      keyfile::set_object_value(*this,
-                                &chroot_facet_union::get_union_overlay_directory,
-                                keyfile, chroot.get_name(),
-                                "union-overlay-directory");
-
-      keyfile::set_object_value(*this,
-                                &chroot_facet_union::get_union_underlay_directory,
-                                keyfile, chroot.get_name(),
-                                "union-underlay-directory");
-    }
-}
-
-void
-chroot_facet_union::set_keyfile (chroot::chroot& chroot,
-                                 keyfile const&  keyfile)
-{
-  bool issession = static_cast<bool>(chroot.get_facet<chroot::facet::session>());
-
-  keyfile::get_object_value(*this, &chroot_facet_union::set_union_type,
-                            keyfile, chroot.get_name(), "union-type",
-                            keyfile::PRIORITY_OPTIONAL);
-
-  // If we are a union, add specific source options here.
-  chroot::facet::source_clonable::ptr psrc
-    (chroot.get_facet<chroot::facet::source_clonable>());
-  if (psrc)
-    psrc->set_keyfile(chroot, keyfile);
-
-  keyfile::get_object_value(*this,
-                            &chroot_facet_union::set_union_mount_options,
-                            keyfile, chroot.get_name(), "union-mount-options",
-                            keyfile::PRIORITY_OPTIONAL);
-
-  keyfile::get_object_value(*this,
-                            &chroot_facet_union::set_union_overlay_directory,
-                            keyfile, chroot.get_name(),
-                            "union-overlay-directory",
-                            (issession && get_union_configured()) ?
-                            keyfile::PRIORITY_REQUIRED :
-                            keyfile::PRIORITY_OPTIONAL);
-
-  keyfile::get_object_value(*this,
-                            &chroot_facet_union::set_union_underlay_directory,
-                            keyfile, chroot.get_name(),
-                            "union-underlay-directory",
-                            (issession && get_union_configured()) ?
-                            keyfile::PRIORITY_REQUIRED :
-                            keyfile::PRIORITY_OPTIONAL);
-}
diff --git a/lib/sbuild/chroot-facet-union.h b/lib/sbuild/chroot-facet-union.h
deleted file mode 100644
index 696f8756..00000000
--- a/lib/sbuild/chroot-facet-union.h
+++ /dev/null
@@ -1,203 +0,0 @@
-/* Copyright © 2008-2013  Jan-Marek Glogowski <glogow@fbihome.de>
- * Copyright © 2005-2013  Roger Leigh <rleigh@debian.org>
- *
- * schroot 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.
- *
- * schroot 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/>.
- *
- *********************************************************************/
-
-#ifndef SBUILD_CHROOT_FACET_UNION_H
-#define SBUILD_CHROOT_FACET_UNION_H
-
-#include <sbuild/chroot/facet/facet.h>
-
-namespace sbuild
-{
-
-  /**
-   * Chroot support for filesystem union based sessions.
-   *
-   * A chroot may offer session support using a filesystem union like
-   * aufs or unionfs.  A new union type may need to adapt the 10mount
-   * or 05union script to properly populate the underlay and mount
-   * directory.  The overlay directory and union setup is already
-   * handled.
-   */
-  class chroot_facet_union : public chroot::facet::facet
-  {
-  public:
-    /// Error codes.
-    enum error_code
-      {
-        UNION_TYPE_UNKNOWN, ///< Unknown filesystem union type.
-        UNION_OVERLAY_ABS,  ///< Union overlay must have an absolute path.
-        UNION_UNDERLAY_ABS  ///< Union underlay must have an absolute path.
-      };
-
-    /// Exception type.
-    typedef custom_error<error_code> error;
-
-    /// A shared_ptr to a chroot facet object.
-    typedef std::shared_ptr<chroot_facet_union> ptr;
-
-    /// A shared_ptr to a const chroot facet object.
-    typedef std::shared_ptr<const chroot_facet_union> const_ptr;
-
-  private:
-    /// The constructor.
-    chroot_facet_union ();
-
-  public:
-    /// The destructor.
-    virtual ~chroot_facet_union ();
-
-    /**
-     * Create a chroot facet.
-     *
-     * @returns a shared_ptr to the new chroot facet.
-     */
-    static ptr
-    create ();
-
-    virtual facet::ptr
-    clone () const;
-
-    std::string const&
-    get_name () const;
-
-    /**
-     * Get fs union configured state.
-     *
-     * @returns if fs union is configured
-     */
-    bool
-    get_union_configured () const;
-
-    /**
-     * Get the filesystem union type.
-     *
-     * @see set_union_type
-     * @returns the union filesytem type.
-     */
-    virtual std::string const&
-    get_union_type () const;
-
-    /**
-     * Set the filesystem union type.
-     *
-     * Currently supported values are aufs, unionfs and none.
-     *
-     * @param union_type the filesystem type.
-     **/
-    virtual void
-    set_union_type (std::string const& union_type);
-
-    /**
-     * Get the filesystem union mount options (branch configuration).
-     *
-     * @see set_union_mount_options
-     * @returns the filesystem union branch configuration.
-     */
-    virtual std::string const&
-    get_union_mount_options () const;
-
-    /**
-     * Set the filesystem union mount options (branch configuration).
-     *
-     * Normally a temporary directory is used as the writeable branch,
-     * which is removed on session end. This allows the building of a
-     * complex union which can merge multiple branches. The string has
-     * to be constructed as expected by the filesystem union type and
-     * is directly used as the mount '-o' option string.
-     *
-     * @param union_mount_options a union filesystem-specific branch
-     * description
-     **/
-    virtual void
-    set_union_mount_options (std::string const& union_mount_options);
-
-    /**
-     * Get the union overlay directory.
-     *
-     * @returns the writeable overlay directory.
-     */
-    virtual std::string const&
-    get_union_overlay_directory () const;
-
-    /**
-     * Set the union overlay directory.
-     *
-     * @param directory the writeable overlay directory.
-     */
-    virtual void
-    set_union_overlay_directory (std::string const& directory);
-
-    /**
-     * Get the union underlay directory.
-     *
-     * @returns the writeable underlay directory.
-     */
-    virtual std::string const&
-    get_union_underlay_directory () const;
-
-    /**
-     * Set the union underlay directory.
-     *
-     * @param directory the writeable underlay directory.
-     */
-    virtual void
-    set_union_underlay_directory (std::string const& directory);
-
-    virtual void
-    setup_env (chroot::chroot const& chroot,
-               environment&          env) const;
-
-    virtual chroot::chroot::session_flags
-    get_session_flags (chroot::chroot const& chroot) const;
-
-    virtual void
-    get_details (chroot::chroot const&  chroot,
-                 format_detail&         detail) const;
-
-    virtual void
-    get_used_keys (string_list& used_keys) const;
-
-    virtual void
-    get_keyfile (chroot::chroot const& chroot,
-                 keyfile&              keyfile) const;
-
-    virtual void
-    set_keyfile (chroot::chroot& chroot,
-                 keyfile         const& keyfile);
-
-  private:
-    /// filesystem union type.
-    std::string union_type;
-    /// Union mount options (branch configuration).
-    std::string union_mount_options;
-    /// Union read-write overlay directory.
-    std::string union_overlay_directory;
-    /// Union read-only underlay directory.
-    std::string union_underlay_directory;
-  };
-
-}
-
-#endif /* SBUILD_CHROOT_FACET_UNION_H */
-
-/*
- * Local Variables:
- * mode:C++
- * End:
- */
diff --git a/lib/sbuild/chroot/block-device.cc b/lib/sbuild/chroot/block-device.cc
index dbb42e28..c27db24f 100644
--- a/lib/sbuild/chroot/block-device.cc
+++ b/lib/sbuild/chroot/block-device.cc
@@ -22,7 +22,7 @@
 #include <sbuild/chroot/facet/session-clonable.h>
 #include <sbuild/chroot/facet/source-clonable.h>
 #ifdef SBUILD_FEATURE_UNION
-#include "chroot-facet-union.h"
+#include <sbuild/chroot/facet/fsunion.h>
 #endif // SBUILD_FEATURE_UNION
 #include "format-detail.h"
 #include "util.h"
@@ -45,7 +45,7 @@ namespace sbuild
       block_device_base()
     {
 #ifdef SBUILD_FEATURE_UNION
-      add_facet(chroot_facet_union::create());
+      add_facet(facet::fsunion::create());
 #endif // SBUILD_FEATURE_UNION
     }
 
@@ -63,8 +63,8 @@ namespace sbuild
       block_device_base(rhs)
     {
 #ifdef SBUILD_FEATURE_UNION
-      if (!get_facet<chroot_facet_union>())
-        add_facet(chroot_facet_union::create());
+      if (!get_facet<facet::fsunion>())
+        add_facet(facet::fsunion::create());
 #endif // SBUILD_FEATURE_UNION
     }
 #endif // SBUILD_FEATURE_LVMSNAP
@@ -137,12 +137,12 @@ namespace sbuild
           else
             {
 #ifdef SBUILD_FEATURE_UNION
-              /* We don't lock the device if union is configured. */
+              /* We don't lock the device if fsunion is configured. */
               const chroot *base = dynamic_cast<const chroot *>(this);
               assert(base);
-              chroot_facet_union::const_ptr puni
-                (base->get_facet<chroot_facet_union>());
-#endif
+              facet::fsunion::const_ptr puni
+                (base->get_facet<facet::fsunion>());
+#endif // SBUILD_FEATURE_UNION
             }
         }
       catch (sbuild::stat::error const& e) // Failed to stat
diff --git a/lib/sbuild/chroot/directory.cc b/lib/sbuild/chroot/directory.cc
index 339ed252..ed8d70e9 100644
--- a/lib/sbuild/chroot/directory.cc
+++ b/lib/sbuild/chroot/directory.cc
@@ -22,7 +22,7 @@
 #include <sbuild/chroot/facet/session-clonable.h>
 #include <sbuild/chroot/facet/source-clonable.h>
 #ifdef SBUILD_FEATURE_UNION
-#include "chroot-facet-union.h"
+#include <sbuild/chroot/facet/fsunion.h>
 #endif // SBUILD_FEATURE_UNION
 #include "format-detail.h"
 #include "lock.h"
@@ -46,7 +46,7 @@ namespace sbuild
       directory_base()
     {
 #ifdef SBUILD_FEATURE_UNION
-      add_facet(chroot_facet_union::create());
+      add_facet(facet::fsunion::create());
 #endif // SBUILD_FEATURE_UNION
     }
 
@@ -60,8 +60,8 @@ namespace sbuild
       directory_base(rhs)
     {
 #ifdef SBUILD_FEATURE_UNION
-      if (!get_facet<chroot_facet_union>())
-        add_facet(chroot_facet_union::create());
+      if (!get_facet<facet::fsunion>())
+        add_facet(facet::fsunion::create());
 #endif // SBUILD_FEATURE_UNION
 
       set_directory(rhs.get_source_subvolume());
diff --git a/lib/sbuild/chroot/facet/fsunion.cc b/lib/sbuild/chroot/facet/fsunion.cc
new file mode 100644
index 00000000..31ed95fe
--- /dev/null
+++ b/lib/sbuild/chroot/facet/fsunion.cc
@@ -0,0 +1,291 @@
+/* Copyright © 2008-2013  Jan-Marek Glogowski <glogow@fbihome.de>
+ * Copyright © 2009-2013  Roger Leigh <rleigh@debian.org>
+ *
+ * schroot 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.
+ *
+ * schroot 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/>.
+ *
+ *********************************************************************/
+
+#include <config.h>
+
+#include <sbuild/chroot/chroot.h>
+#include <sbuild/chroot/facet/session.h>
+#include <sbuild/chroot/facet/fsunion.h>
+#include <sbuild/chroot/facet/source-clonable.h>
+#include "feature.h"
+
+#include <cassert>
+
+using boost::format;
+using std::endl;
+using namespace sbuild;
+
+namespace
+{
+
+  sbuild::feature feature_union("UNION", N_("Support for filesystem unioning"));
+
+}
+
+namespace sbuild
+{
+  namespace chroot
+  {
+    namespace facet
+    {
+
+      template<>
+      error<fsunion::error_code>::map_type
+      error<fsunion::error_code>::error_strings =
+        {
+          // TRANSLATORS: %1% = chroot fs type
+          {chroot::facet::fsunion::FSUNION_TYPE_UNKNOWN, N_("Unknown filesystem union type ‘%1%’")},
+          {chroot::facet::fsunion::FSUNION_OVERLAY_ABS,  N_("Union overlay must have an absolute path")},
+          {chroot::facet::fsunion::FSUNION_UNDERLAY_ABS, N_("Union underlay must have an absolute path")}
+        };
+
+      fsunion::fsunion ():
+        facet(),
+        union_type("none"),
+        union_overlay_directory(SCHROOT_OVERLAY_DIR),
+        union_underlay_directory(SCHROOT_UNDERLAY_DIR)
+      {
+      }
+
+      fsunion::~fsunion ()
+      {
+      }
+
+      fsunion::ptr
+      fsunion::create ()
+      {
+        return ptr(new fsunion());
+      }
+
+      facet::ptr
+      fsunion::clone () const
+      {
+        return ptr(new fsunion(*this));
+      }
+
+      std::string const&
+      fsunion::get_name () const
+      {
+        static const std::string name("union");
+
+        return name;
+      }
+
+      bool
+      fsunion::get_union_configured () const
+      {
+        return get_union_type() != "none";
+      }
+
+      std::string const&
+      fsunion::get_union_overlay_directory () const
+      {
+        return this->union_overlay_directory;
+      }
+
+      void
+      fsunion::set_union_overlay_directory
+      (std::string const& directory)
+      {
+        if (!is_absname(directory))
+          throw error(directory, FSUNION_OVERLAY_ABS);
+
+        this->union_overlay_directory = directory;
+      }
+
+      std::string const&
+      fsunion::get_union_underlay_directory () const
+      {
+        return this->union_underlay_directory;
+      }
+
+      void
+      fsunion::set_union_underlay_directory
+      (std::string const& directory)
+      {
+        if (!is_absname(directory))
+          throw error(directory, FSUNION_UNDERLAY_ABS);
+
+        this->union_underlay_directory = directory;
+      }
+
+      std::string const&
+      fsunion::get_union_type () const
+      {
+        return this->union_type;
+      }
+
+      void
+      fsunion::set_union_type (std::string const& type)
+      {
+        if (type == "aufs" ||
+            type == "overlayfs" ||
+            type == "unionfs" ||
+            type == "none")
+          this->union_type = type;
+        else
+          throw error(type, FSUNION_TYPE_UNKNOWN);
+
+        chroot *base = dynamic_cast<chroot *>(this->owner);
+        assert(base);
+
+        if (this->union_type != "none")
+          {
+            if (!base->get_facet<source_clonable>())
+              base->add_facet(source_clonable::create());
+          }
+        else
+          base->remove_facet<source_clonable>();
+      }
+
+      std::string const&
+      fsunion::get_union_mount_options () const
+      {
+        return union_mount_options;
+      }
+
+      void
+      fsunion::set_union_mount_options
+      (std::string const& union_mount_options)
+      {
+        this->union_mount_options = union_mount_options;
+      }
+
+      void
+      fsunion::setup_env (chroot const& chroot,
+                          environment&  env) const
+      {
+        env.add("CHROOT_UNION_TYPE", get_union_type());
+        if (get_union_configured())
+          {
+            env.add("CHROOT_UNION_MOUNT_OPTIONS",
+                    get_union_mount_options());
+            env.add("CHROOT_UNION_OVERLAY_DIRECTORY",
+                    get_union_overlay_directory());
+            env.add("CHROOT_UNION_UNDERLAY_DIRECTORY",
+                    get_union_underlay_directory());
+          }
+      }
+
+      chroot::session_flags
+      fsunion::get_session_flags (chroot const& chroot) const
+      {
+        chroot::session_flags flags = chroot::SESSION_NOFLAGS;
+
+        if (get_union_configured() && chroot.get_facet<session>())
+          flags = chroot::SESSION_PURGE;
+
+        return flags;
+      }
+
+      void
+      fsunion::get_details (chroot const& chroot,
+                            format_detail&        detail) const
+      {
+        detail.add(_("Filesystem Union Type"), get_union_type());
+        if (get_union_configured())
+          {
+            if (!this->union_mount_options.empty())
+              detail.add(_("Filesystem Union Mount Options"),
+                         get_union_mount_options());
+            if (!this->union_overlay_directory.empty())
+              detail.add(_("Filesystem Union Overlay Directory"),
+                         get_union_overlay_directory());
+            if (!this->union_underlay_directory.empty())
+              detail.add(_("Filesystem Union Underlay Directory"),
+                         get_union_underlay_directory());
+          }
+      }
+
+      void
+      fsunion::get_used_keys (string_list& used_keys) const
+      {
+        used_keys.push_back("union-type");
+        used_keys.push_back("union-mount-options");
+        used_keys.push_back("union-overlay-directory");
+        used_keys.push_back("union-underlay-directory");
+      }
+
+      void
+      fsunion::get_keyfile (chroot const& chroot,
+                            keyfile&      keyfile) const
+      {
+        keyfile::set_object_value(*this, &fsunion::get_union_type,
+                                  keyfile, chroot.get_name(), "union-type");
+
+        if (get_union_configured())
+          {
+            keyfile::set_object_value(*this,
+                                      &fsunion::get_union_mount_options,
+                                      keyfile, chroot.get_name(),
+                                      "union-mount-options");
+
+            keyfile::set_object_value(*this,
+                                      &fsunion::get_union_overlay_directory,
+                                      keyfile, chroot.get_name(),
+                                      "union-overlay-directory");
+
+            keyfile::set_object_value(*this,
+                                      &fsunion::get_union_underlay_directory,
+                                      keyfile, chroot.get_name(),
+                                      "union-underlay-directory");
+          }
+      }
+
+      void
+      fsunion::set_keyfile (chroot&        chroot,
+                            keyfile const& keyfile)
+      {
+        bool issession = static_cast<bool>(chroot.get_facet<session>());
+
+        keyfile::get_object_value(*this, &fsunion::set_union_type,
+                                  keyfile, chroot.get_name(), "union-type",
+                                  keyfile::PRIORITY_OPTIONAL);
+
+        // If we are a union, add specific source options here.
+        source_clonable::ptr psrc
+          (chroot.get_facet<source_clonable>());
+        if (psrc)
+          psrc->set_keyfile(chroot, keyfile);
+
+        keyfile::get_object_value(*this,
+                                  &fsunion::set_union_mount_options,
+                                  keyfile, chroot.get_name(), "union-mount-options",
+                                  keyfile::PRIORITY_OPTIONAL);
+
+        keyfile::get_object_value(*this,
+                                  &fsunion::set_union_overlay_directory,
+                                  keyfile, chroot.get_name(),
+                                  "union-overlay-directory",
+                                  (issession && get_union_configured()) ?
+                                  keyfile::PRIORITY_REQUIRED :
+                                  keyfile::PRIORITY_OPTIONAL);
+
+        keyfile::get_object_value(*this,
+                                  &fsunion::set_union_underlay_directory,
+                                  keyfile, chroot.get_name(),
+                                  "union-underlay-directory",
+                                  (issession && get_union_configured()) ?
+                                  keyfile::PRIORITY_REQUIRED :
+                                  keyfile::PRIORITY_OPTIONAL);
+      }
+
+    }
+  }
+}
diff --git a/lib/sbuild/chroot/facet/fsunion.h b/lib/sbuild/chroot/facet/fsunion.h
new file mode 100644
index 00000000..2cb1627b
--- /dev/null
+++ b/lib/sbuild/chroot/facet/fsunion.h
@@ -0,0 +1,209 @@
+/* Copyright © 2008-2013  Jan-Marek Glogowski <glogow@fbihome.de>
+ * Copyright © 2005-2013  Roger Leigh <rleigh@debian.org>
+ *
+ * schroot 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.
+ *
+ * schroot 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/>.
+ *
+ *********************************************************************/
+
+#ifndef SBUILD_CHROOT_FACET_FSUNION_H
+#define SBUILD_CHROOT_FACET_FSUNION_H
+
+#include <sbuild/chroot/facet/facet.h>
+
+namespace sbuild
+{
+  namespace chroot
+  {
+    namespace facet
+    {
+
+      /**
+       * Chroot support for filesystem union based sessions.
+       *
+       * A chroot may offer session support using a filesystem union like
+       * aufs or unionfs.  A new union type may need to adapt the 10mount
+       * or 05union script to properly populate the underlay and mount
+       * directory.  The overlay directory and union setup is already
+       * handled.
+       */
+      class fsunion : public facet
+      {
+      public:
+        /// Error codes.
+        enum error_code
+          {
+            FSUNION_TYPE_UNKNOWN, ///< Unknown filesystem union type.
+            FSUNION_OVERLAY_ABS,  ///< Union overlay must have an absolute path.
+            FSUNION_UNDERLAY_ABS  ///< Union underlay must have an absolute path.
+          };
+
+        /// Exception type.
+        typedef custom_error<error_code> error;
+
+        /// A shared_ptr to a chroot facet object.
+        typedef std::shared_ptr<fsunion> ptr;
+
+        /// A shared_ptr to a const chroot facet object.
+        typedef std::shared_ptr<const fsunion> const_ptr;
+
+      private:
+        /// The constructor.
+        fsunion ();
+
+      public:
+        /// The destructor.
+        virtual ~fsunion ();
+
+        /**
+         * Create a chroot facet.
+         *
+         * @returns a shared_ptr to the new chroot facet.
+         */
+        static ptr
+        create ();
+
+        virtual facet::ptr
+        clone () const;
+
+        std::string const&
+        get_name () const;
+
+        /**
+         * Get fs union configured state.
+         *
+         * @returns if fs union is configured
+         */
+        bool
+        get_union_configured () const;
+
+        /**
+         * Get the filesystem union type.
+         *
+         * @see set_union_type
+         * @returns the union filesytem type.
+         */
+        virtual std::string const&
+        get_union_type () const;
+
+        /**
+         * Set the filesystem union type.
+         *
+         * Currently supported values are aufs, unionfs and none.
+         *
+         * @param union_type the filesystem type.
+         **/
+        virtual void
+        set_union_type (std::string const& union_type);
+
+        /**
+         * Get the filesystem union mount options (branch configuration).
+         *
+         * @see set_union_mount_options
+         * @returns the filesystem union branch configuration.
+         */
+        virtual std::string const&
+        get_union_mount_options () const;
+
+        /**
+         * Set the filesystem union mount options (branch configuration).
+         *
+         * Normally a temporary directory is used as the writeable branch,
+         * which is removed on session end. This allows the building of a
+         * complex union which can merge multiple branches. The string has
+         * to be constructed as expected by the filesystem union type and
+         * is directly used as the mount '-o' option string.
+         *
+         * @param union_mount_options a union filesystem-specific branch
+         * description
+         **/
+        virtual void
+        set_union_mount_options (std::string const& union_mount_options);
+
+        /**
+         * Get the union overlay directory.
+         *
+         * @returns the writeable overlay directory.
+         */
+        virtual std::string const&
+        get_union_overlay_directory () const;
+
+        /**
+         * Set the union overlay directory.
+         *
+         * @param directory the writeable overlay directory.
+         */
+        virtual void
+        set_union_overlay_directory (std::string const& directory);
+
+        /**
+         * Get the union underlay directory.
+         *
+         * @returns the writeable underlay directory.
+         */
+        virtual std::string const&
+        get_union_underlay_directory () const;
+
+        /**
+         * Set the union underlay directory.
+         *
+         * @param directory the writeable underlay directory.
+         */
+        virtual void
+        set_union_underlay_directory (std::string const& directory);
+
+        virtual void
+        setup_env (chroot const& chroot,
+                   environment&  env) const;
+
+        virtual chroot::session_flags
+        get_session_flags (chroot const& chroot) const;
+
+        virtual void
+        get_details (chroot const&  chroot,
+                     format_detail& detail) const;
+
+        virtual void
+        get_used_keys (string_list& used_keys) const;
+
+        virtual void
+        get_keyfile (chroot const& chroot,
+                     keyfile&      keyfile) const;
+
+        virtual void
+        set_keyfile (chroot&        chroot,
+                     keyfile const& keyfile);
+
+      private:
+        /// filesystem union type.
+        std::string union_type;
+        /// Union mount options (branch configuration).
+        std::string union_mount_options;
+        /// Union read-write overlay directory.
+        std::string union_overlay_directory;
+        /// Union read-only underlay directory.
+        std::string union_underlay_directory;
+      };
+
+    }
+  }
+}
+
+#endif /* SBUILD_CHROOT_FACET_FSUNION_H */
+
+/*
+ * Local Variables:
+ * mode:C++
+ * End:
+ */
diff --git a/lib/sbuild/chroot/facet/session-clonable.cc b/lib/sbuild/chroot/facet/session-clonable.cc
index 1cee2dc0..8d3eea02 100644
--- a/lib/sbuild/chroot/facet/session-clonable.cc
+++ b/lib/sbuild/chroot/facet/session-clonable.cc
@@ -37,7 +37,7 @@
 #include <sbuild/chroot/btrfs-snapshot.h>
 #endif // SBUILD_FEATURE_BTRFSSNAP
 #ifdef SBUILD_FEATURE_UNION
-#include "chroot-facet-union.h"
+#include <sbuild/chroot/facet/fsunion.h>
 #endif // SBUILD_FEATURE_UNION
 #include "format-detail.h"
 
@@ -203,12 +203,12 @@ namespace sbuild
 
 #ifdef SBUILD_FEATURE_UNION
         // If the parent did not have a union facet, then neither should we.
-        chroot_facet_union::const_ptr pparentuni(parent.get_facet<chroot_facet_union>());
+        fsunion::const_ptr pparentuni(parent.get_facet<fsunion>());
         if (!pparentuni)
-          clone->remove_facet<chroot_facet_union>();
+          clone->remove_facet<fsunion>();
 
         /* Filesystem unions need the overlay directory specifying. */
-        chroot_facet_union::ptr puni(clone->get_facet<chroot_facet_union>());
+        fsunion::ptr puni(clone->get_facet<fsunion>());
 
         if (puni)
           {
diff --git a/lib/sbuild/chroot/facet/source-clonable.cc b/lib/sbuild/chroot/facet/source-clonable.cc
index 707950cf..09294e4a 100644
--- a/lib/sbuild/chroot/facet/source-clonable.cc
+++ b/lib/sbuild/chroot/facet/source-clonable.cc
@@ -23,7 +23,7 @@
 #include <sbuild/chroot/facet/source-clonable.h>
 #include <sbuild/chroot/facet/source.h>
 #ifdef SBUILD_FEATURE_UNION
-#include "chroot-facet-union.h"
+#include <sbuild/chroot/facet/fsunion.h>
 #endif // SBUILD_FEATURE_UNION
 
 #include <cassert>
@@ -87,7 +87,7 @@ namespace sbuild
         clone->set_aliases(clone->get_aliases());
 
 #ifdef SBUILD_FEATURE_UNION
-        clone->remove_facet<chroot_facet_union>();
+        clone->remove_facet<fsunion>();
 #endif // SBUILD_FEATURE_UNION
 
         clone->remove_facet<source_clonable>();
diff --git a/lib/sbuild/chroot/loopback.cc b/lib/sbuild/chroot/loopback.cc
index 3e16e789..d09ecbcd 100644
--- a/lib/sbuild/chroot/loopback.cc
+++ b/lib/sbuild/chroot/loopback.cc
@@ -23,7 +23,7 @@
 #include <sbuild/chroot/facet/source-clonable.h>
 #include <sbuild/chroot/facet/mountable.h>
 #ifdef SBUILD_FEATURE_UNION
-#include "chroot-facet-union.h"
+#include <sbuild/chroot/facet/fsunion.h>
 #endif // SBUILD_FEATURE_UNION
 #include "format-detail.h"
 #include "lock.h"
@@ -49,7 +49,7 @@ namespace sbuild
     {
       add_facet(facet::mountable::create());
 #ifdef SBUILD_FEATURE_UNION
-      add_facet(chroot_facet_union::create());
+      add_facet(facet::fsunion::create());
 #endif // SBUILD_FEATURE_UNION
     }