sbuild::chroot: Migrate btrfs-snapshot to storage facet

6 files changed, 372 insertions, 642 deletions

diff --git a/lib/sbuild/Makefile.am b/lib/sbuild/Makefile.am
index 85a120a2..986571a7 100644
--- a/lib/sbuild/Makefile.am
+++ b/lib/sbuild/Makefile.am
@@ -25,6 +25,7 @@ lib_sbuild_public_h_sources =				\
 	lib/sbuild/chroot/custom.h			\
 	lib/sbuild/chroot/directory.h			\
 	lib/sbuild/chroot/directory-base.h		\
+	lib/sbuild/chroot/facet/btrfs-snapshot.cc	\
 	lib/sbuild/chroot/facet/facet.h			\
 	lib/sbuild/chroot/facet/directory-base.h	\
 	lib/sbuild/chroot/facet/mountable.h		\
@@ -115,6 +116,7 @@ lib_sbuild_public_cc_sources =				\
 	lib/sbuild/chroot/custom.cc			\
 	lib/sbuild/chroot/directory.cc			\
 	lib/sbuild/chroot/directory-base.cc		\
+	lib/sbuild/chroot/facet/btrfs-snapshot.cc	\
 	lib/sbuild/chroot/facet/facet.cc		\
 	lib/sbuild/chroot/facet/directory-base.cc	\
 	lib/sbuild/chroot/facet/mountable.cc		\
diff --git a/lib/sbuild/chroot/btrfs-snapshot.cc b/lib/sbuild/chroot/btrfs-snapshot.cc
index 60437e86..e497acd4 100644
--- a/lib/sbuild/chroot/btrfs-snapshot.cc
+++ b/lib/sbuild/chroot/btrfs-snapshot.cc
@@ -18,8 +18,9 @@
 
 #include <config.h>
 
-#include <chroot/btrfs-snapshot.h>
+#include <sbuild/chroot/btrfs-snapshot.h>
 #include <sbuild/chroot/directory.h>
+#include <sbuild/chroot/facet/btrfs-snapshot.h>
 #include <sbuild/chroot/facet/session.h>
 #include <sbuild/chroot/facet/session-clonable.h>
 #include <sbuild/chroot/facet/source-clonable.h>
@@ -41,19 +42,13 @@ namespace sbuild
   {
 
     btrfs_snapshot::btrfs_snapshot ():
-      chroot(),
-      source_subvolume(),
-      snapshot_directory(),
-      snapshot_name()
+      chroot()
     {
-      add_facet(facet::source_clonable::create());
+      add_facet(facet::btrfs_snapshot::create());
     }
 
     btrfs_snapshot::btrfs_snapshot (const btrfs_snapshot& rhs):
-      chroot(rhs),
-      source_subvolume(rhs.source_subvolume),
-      snapshot_directory(rhs.snapshot_directory),
-      snapshot_name(rhs.snapshot_name)
+      chroot(rhs)
     {
     }
 
@@ -97,180 +92,5 @@ namespace sbuild
       return clone;
     }
 
-    std::string const&
-    btrfs_snapshot::get_source_subvolume () const
-    {
-      return this->source_subvolume;
-    }
-
-    void
-    btrfs_snapshot::set_source_subvolume (std::string const& source_subvolume)
-    {
-      if (!is_absname(source_subvolume))
-        throw error(source_subvolume, DIRECTORY_ABS);
-
-      this->source_subvolume = source_subvolume;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_snapshot_directory () const
-    {
-      return this->snapshot_directory;
-    }
-
-    void
-    btrfs_snapshot::set_snapshot_directory (std::string const& snapshot_directory)
-    {
-      if (!is_absname(snapshot_directory))
-        throw error(source_subvolume, DIRECTORY_ABS);
-
-      this->snapshot_directory = snapshot_directory;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_snapshot_name () const
-    {
-      return this->snapshot_name;
-    }
-
-    void
-    btrfs_snapshot::set_snapshot_name (std::string const& snapshot_name)
-    {
-      if (!is_absname(snapshot_name))
-        throw error(source_subvolume, DIRECTORY_ABS);
-
-      this->snapshot_name = snapshot_name;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_chroot_type () const
-    {
-      static const std::string type("btrfs-snapshot");
-
-      return type;
-    }
-
-    std::string
-    btrfs_snapshot::get_path () const
-    {
-      return get_mount_location();
-    }
-
-    void
-    btrfs_snapshot::setup_env (chroot const& chroot,
-                               environment&  env) const
-    {
-      chroot::setup_env(chroot, env);
-
-      env.add("CHROOT_BTRFS_SOURCE_SUBVOLUME", get_source_subvolume());
-      env.add("CHROOT_BTRFS_SNAPSHOT_DIRECTORY", get_snapshot_directory());
-      env.add("CHROOT_BTRFS_SNAPSHOT_NAME", get_snapshot_name());
-    }
-
-    void
-    btrfs_snapshot::setup_lock (chroot::setup_type type,
-                                bool               lock,
-                                int                status)
-    {
-      /* Create or unlink session information. */
-      if ((type == SETUP_START && lock == true) ||
-          (type == SETUP_STOP && lock == false && status == 0))
-        {
-          bool start = (type == SETUP_START);
-          get_facet_strict<facet::session>()->setup_session_info(start);
-        }
-    }
-
-    chroot::chroot::session_flags
-    btrfs_snapshot::get_session_flags (chroot const& chroot) const
-    {
-      session_flags flags = SESSION_NOFLAGS;
-
-      if (get_facet<facet::session>())
-        flags = flags | SESSION_PURGE;
-
-      return flags;
-    }
-
-    void
-    btrfs_snapshot::get_details (chroot const& chroot,
-                                 format_detail& detail) const
-    {
-      chroot::get_details(chroot, detail);
-
-      if (!this->get_source_subvolume().empty())
-        detail.add(_("Btrfs Source Subvolume"), get_source_subvolume());
-      if (!this->get_snapshot_directory().empty())
-        detail.add(_("Btrfs Snapshot Directory"), get_snapshot_directory());
-      if (!this->get_snapshot_name().empty())
-        detail.add(_("Btrfs Snapshot Name"), get_snapshot_name());
-    }
-
-    void
-    btrfs_snapshot::get_used_keys (string_list& used_keys) const
-    {
-      chroot::get_used_keys(used_keys);
-
-      used_keys.push_back("btrfs-source-subvolume");
-      used_keys.push_back("btrfs-snapshot-directory");
-      used_keys.push_back("btrfs-snapshot-name");
-    }
-
-    void
-    btrfs_snapshot::get_keyfile (chroot const& chroot,
-                                 keyfile& keyfile) const
-    {
-      chroot::get_keyfile(chroot, keyfile);
-
-      bool issession = static_cast<bool>(get_facet<facet::session>());
-
-      if (!issession)
-        keyfile::set_object_value(*this,
-                                  &btrfs_snapshot::get_source_subvolume,
-                                  keyfile, get_name(),
-                                  "btrfs-source-subvolume");
-
-      if (!issession)
-        keyfile::set_object_value(*this,
-                                  &btrfs_snapshot::get_snapshot_directory,
-                                  keyfile, get_name(),
-                                  "btrfs-snapshot-directory");
-
-      if (issession)
-        keyfile::set_object_value(*this,
-                                  &btrfs_snapshot::get_snapshot_name,
-                                  keyfile, get_name(),
-                                  "btrfs-snapshot-name");
-    }
-
-    void
-    btrfs_snapshot::set_keyfile (chroot&        chroot,
-                                 keyfile const& keyfile)
-    {
-      chroot::set_keyfile(chroot, keyfile);
-
-      bool issession = static_cast<bool>(get_facet<facet::session>());
-
-      keyfile::get_object_value(*this, &btrfs_snapshot::set_source_subvolume,
-                                keyfile, get_name(), "btrfs-source-subvolume",
-                                issession ?
-                                keyfile::PRIORITY_DISALLOWED :
-                                keyfile::PRIORITY_REQUIRED
-                                ); // Only needed for creating snapshot, not using snapshot
-
-      keyfile::get_object_value(*this, &btrfs_snapshot::set_snapshot_directory,
-                                keyfile, get_name(), "btrfs-snapshot-directory",
-                                issession ?
-                                keyfile::PRIORITY_DISALLOWED :
-                                keyfile::PRIORITY_REQUIRED
-                                ); // Only needed for creating snapshot, not using snapshot
-
-      keyfile::get_object_value(*this, &btrfs_snapshot::set_snapshot_name,
-                                keyfile, get_name(), "btrfs-snapshot-name",
-                                issession ?
-                                keyfile::PRIORITY_REQUIRED :
-                                keyfile::PRIORITY_DISALLOWED);
-    }
-
   }
 }
diff --git a/lib/sbuild/chroot/btrfs-snapshot.h b/lib/sbuild/chroot/btrfs-snapshot.h
index 81b64387..4e424c86 100644
--- a/lib/sbuild/chroot/btrfs-snapshot.h
+++ b/lib/sbuild/chroot/btrfs-snapshot.h
@@ -56,100 +56,6 @@ namespace sbuild
 
       virtual chroot::ptr
       clone_source () const;
-
-      /**
-       * Get the source subvolume path.  This is used by "btrfs
-       * subvolume snapshot".
-       *
-       * @returns the source subvolume.
-       */
-      std::string const&
-      get_source_subvolume () const;
-
-      /**
-       * Set the source subvolume path.  This is used by "btrfs
-       * subvolume snapshot".
-       *
-       * @param source_subvolume the source subvolume.
-       */
-      void
-      set_source_subvolume (std::string const& source_subvolume);
-
-      /**
-       * Get the snapshot directory.
-       *
-       * @returns the directory.
-       */
-      std::string const&
-      get_snapshot_directory () const;
-
-      /**
-       * Set the snapshot directory.
-       *
-       * @param snapshot_directory the snapshot directory.
-       */
-      void
-      set_snapshot_directory (std::string const& snapshot_directory);
-
-      /**
-       * Get the snapshot name.  This is used by "btrfs subvolume
-       * snapshot", and is the full path to the snapshot.
-       *
-       * @returns the name.
-       */
-      std::string const&
-      get_snapshot_name () const;
-
-      /**
-       * Set the snapshot name.  This is used by "btrfs subvolume
-       * snapshot", and is the full path to the snapshot.
-       *
-       * @param snapshot_name the snapshot name.
-       */
-      void
-      set_snapshot_name (std::string const& snapshot_name);
-
-      virtual std::string const&
-      get_chroot_type () const;
-
-      virtual std::string
-      get_path () const;
-
-      virtual void
-      setup_env (chroot const& chroot,
-                 environment&  env) const;
-
-      virtual session_flags
-      get_session_flags (chroot const& chroot) const;
-
-    protected:
-      virtual void
-      setup_lock (chroot::setup_type type,
-                  bool               lock,
-                  int                status);
-
-      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:
-      /// Btrfs source subvolume
-      std::string source_subvolume;
-      /// Btrfs snapshot path
-      std::string snapshot_directory;
-      /// Btrfs snapshot name
-      std::string snapshot_name;
     };
 
   }
diff --git a/lib/sbuild/chroot/facet/btrfs-snapshot.cc b/lib/sbuild/chroot/facet/btrfs-snapshot.cc
index 407b70a3..f0c2ba3b 100644
--- a/lib/sbuild/chroot/facet/btrfs-snapshot.cc
+++ b/lib/sbuild/chroot/facet/btrfs-snapshot.cc
@@ -18,13 +18,12 @@
 
 #include <config.h>
 
-#include <chroot/btrfs-snapshot.h>
-#include <sbuild/chroot/directory.h>
-#include <sbuild/chroot/facet/session.h>
+#include <sbuild/chroot/facet/btrfs-snapshot.h>
+#include <sbuild/chroot/facet/mountable.h>
 #include <sbuild/chroot/facet/session-clonable.h>
+#include <sbuild/chroot/facet/session.h>
 #include <sbuild/chroot/facet/source-clonable.h>
 #include "format-detail.h"
-#include "lock.h"
 
 #include <cassert>
 #include <cerrno>
@@ -39,238 +38,224 @@ namespace sbuild
 {
   namespace chroot
   {
-
-    btrfs_snapshot::btrfs_snapshot ():
-      chroot(),
-      source_subvolume(),
-      snapshot_directory(),
-      snapshot_name()
-    {
-      add_facet(facet::source_clonable::create());
-    }
-
-    btrfs_snapshot::btrfs_snapshot (const btrfs_snapshot& rhs):
-      chroot(rhs),
-      source_subvolume(rhs.source_subvolume),
-      snapshot_directory(rhs.snapshot_directory),
-      snapshot_name(rhs.snapshot_name)
-    {
-    }
-
-    btrfs_snapshot::~btrfs_snapshot ()
-    {
-    }
-
-    chroot::chroot::ptr
-    btrfs_snapshot::clone () const
-    {
-      return ptr(new btrfs_snapshot(*this));
-    }
-
-    chroot::chroot::ptr
-    btrfs_snapshot::clone_session (std::string const& session_id,
-                                   std::string const& alias,
-                                   std::string const& user,
-                                   bool               root) const
-    {
-      facet::session_clonable::const_ptr psess
-        (get_facet<facet::session_clonable>());
-      assert(psess);
-
-      ptr session(new btrfs_snapshot(*this));
-      psess->clone_session_setup(*this, session, session_id, alias, user, root);
-
-      return session;
-    }
-
-    chroot::chroot::ptr
-    btrfs_snapshot::clone_source () const
-    {
-      ptr clone(new directory(*this));
-
-      facet::source_clonable::const_ptr psrc
-        (get_facet<facet::source_clonable>());
-      assert(psrc);
-
-      psrc->clone_source_setup(*this, clone);
-
-      return clone;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_source_subvolume () const
+    namespace facet
     {
-      return this->source_subvolume;
-    }
 
-    void
-    btrfs_snapshot::set_source_subvolume (std::string const& source_subvolume)
-    {
-      if (!is_absname(source_subvolume))
-        throw error(source_subvolume, DIRECTORY_ABS);
+      btrfs_snapshot::btrfs_snapshot ():
+        storage(),
+        source_subvolume(),
+        snapshot_directory(),
+        snapshot_name()
+      {
+      }
+
+      btrfs_snapshot::btrfs_snapshot (const btrfs_snapshot& rhs):
+        storage(rhs),
+        source_subvolume(rhs.source_subvolume),
+        snapshot_directory(rhs.snapshot_directory),
+        snapshot_name(rhs.snapshot_name)
+      {
+      }
+
+      btrfs_snapshot::~btrfs_snapshot ()
+      {
+      }
+
+      void
+      btrfs_snapshot::set_chroot (chroot& chroot)
+      {
+        storage::set_chroot(chroot);
+        if (!owner->get_facet<source_clonable>())
+          owner->add_facet(source_clonable::create());
+      }
+
+      std::string const&
+      btrfs_snapshot::get_name () const
+      {
+        static const std::string name("btrfs-snapshot");
+
+        return name;
+      }
+
+      btrfs_snapshot::ptr
+      btrfs_snapshot::create ()
+      {
+        return ptr(new btrfs_snapshot());
+      }
+
+      facet::ptr
+      btrfs_snapshot::clone () const
+      {
+        return ptr(new btrfs_snapshot(*this));
+      }
+
+      std::string const&
+      btrfs_snapshot::get_source_subvolume () const
+      {
+        return this->source_subvolume;
+      }
+
+      void
+      btrfs_snapshot::set_source_subvolume (std::string const& source_subvolume)
+      {
+        if (!is_absname(source_subvolume))
+          throw error(source_subvolume, chroot::DIRECTORY_ABS);
+
+        this->source_subvolume = source_subvolume;
+      }
+
+      std::string const&
+      btrfs_snapshot::get_snapshot_directory () const
+      {
+        return this->snapshot_directory;
+      }
+
+      void
+      btrfs_snapshot::set_snapshot_directory (std::string const& snapshot_directory)
+      {
+        if (!is_absname(snapshot_directory))
+          throw error(source_subvolume, chroot::DIRECTORY_ABS);
+
+        this->snapshot_directory = snapshot_directory;
+      }
+
+      std::string const&
+      btrfs_snapshot::get_snapshot_name () const
+      {
+        return this->snapshot_name;
+      }
+
+      void
+      btrfs_snapshot::set_snapshot_name (std::string const& snapshot_name)
+      {
+        if (!is_absname(snapshot_name))
+          throw error(source_subvolume, chroot::DIRECTORY_ABS);
+
+        this->snapshot_name = snapshot_name;
+      }
+
+      std::string
+      btrfs_snapshot::get_path () const
+      {
+        return owner->get_mount_location();
+      }
+
+      void
+      btrfs_snapshot::setup_env (chroot const& chroot,
+                                 environment&  env) const
+      {
+        storage::setup_env(chroot, env);
+
+        env.add("CHROOT_BTRFS_SOURCE_SUBVOLUME", get_source_subvolume());
+        env.add("CHROOT_BTRFS_SNAPSHOT_DIRECTORY", get_snapshot_directory());
+        env.add("CHROOT_BTRFS_SNAPSHOT_NAME", get_snapshot_name());
+      }
+
+      void
+      btrfs_snapshot::setup_lock (chroot::setup_type type,
+                                  bool               lock,
+                                  int                status)
+      {
+        /* Create or unlink session information. */
+        if ((type == chroot::SETUP_START && lock == true) ||
+            (type == chroot::SETUP_STOP && lock == false && status == 0))
+          {
+            bool start = (type == chroot::SETUP_START);
+            owner->get_facet_strict<session>()->setup_session_info(start);
+          }
+      }
+
+      chroot::session_flags
+      btrfs_snapshot::get_session_flags (chroot const& chroot) const
+      {
+        chroot::session_flags flags = chroot::SESSION_NOFLAGS;
+
+        if (owner->get_facet<session>())
+          flags = flags | chroot::SESSION_PURGE;
+
+        return flags;
+      }
+
+      void
+      btrfs_snapshot::get_details (chroot const&  chroot,
+                                   format_detail& detail) const
+      {
+        storage::get_details(chroot, detail);
+
+        if (!this->get_source_subvolume().empty())
+          detail.add(_("Btrfs Source Subvolume"), get_source_subvolume());
+        if (!this->get_snapshot_directory().empty())
+          detail.add(_("Btrfs Snapshot Directory"), get_snapshot_directory());
+        if (!this->get_snapshot_name().empty())
+          detail.add(_("Btrfs Snapshot Name"), get_snapshot_name());
+      }
+
+      void
+      btrfs_snapshot::get_used_keys (string_list& used_keys) const
+      {
+        storage::get_used_keys(used_keys);
+
+        used_keys.push_back("btrfs-source-subvolume");
+        used_keys.push_back("btrfs-snapshot-directory");
+        used_keys.push_back("btrfs-snapshot-name");
+      }
+
+      void
+      btrfs_snapshot::get_keyfile (chroot const& chroot,
+                                   keyfile&      keyfile) const
+      {
+        storage::get_keyfile(chroot, keyfile);
+
+        bool issession = static_cast<bool>(owner->get_facet<session>());
+
+        if (!issession)
+          keyfile::set_object_value(*this,
+                                    &btrfs_snapshot::get_source_subvolume,
+                                    keyfile, chroot.get_name(),
+                                    "btrfs-source-subvolume");
+
+        if (!issession)
+          keyfile::set_object_value(*this,
+                                    &btrfs_snapshot::get_snapshot_directory,
+                                    keyfile, chroot.get_name(),
+                                    "btrfs-snapshot-directory");
+
+        if (issession)
+          keyfile::set_object_value(*this,
+                                    &btrfs_snapshot::get_snapshot_name,
+                                    keyfile, chroot.get_name(),
+                                    "btrfs-snapshot-name");
+      }
+
+      void
+      btrfs_snapshot::set_keyfile (chroot&        chroot,
+                                   keyfile const& keyfile)
+      {
+        storage::set_keyfile(chroot, keyfile);
+
+        bool issession = static_cast<bool>(owner->get_facet<session>());
+
+        keyfile::get_object_value(*this, &btrfs_snapshot::set_source_subvolume,
+                                  keyfile, chroot.get_name(), "btrfs-source-subvolume",
+                                  issession ?
+                                  keyfile::PRIORITY_DISALLOWED :
+                                  keyfile::PRIORITY_REQUIRED
+                                  ); // Only needed for creating snapshot, not using snapshot
+
+        keyfile::get_object_value(*this, &btrfs_snapshot::set_snapshot_directory,
+                                  keyfile, chroot.get_name(), "btrfs-snapshot-directory",
+                                  issession ?
+                                  keyfile::PRIORITY_DISALLOWED :
+                                  keyfile::PRIORITY_REQUIRED
+                                  ); // Only needed for creating snapshot, not using snapshot
+
+        keyfile::get_object_value(*this, &btrfs_snapshot::set_snapshot_name,
+                                  keyfile, chroot.get_name(), "btrfs-snapshot-name",
+                                  issession ?
+                                  keyfile::PRIORITY_REQUIRED :
+                                  keyfile::PRIORITY_DISALLOWED);
+      }
 
-      this->source_subvolume = source_subvolume;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_snapshot_directory () const
-    {
-      return this->snapshot_directory;
-    }
-
-    void
-    btrfs_snapshot::set_snapshot_directory (std::string const& snapshot_directory)
-    {
-      if (!is_absname(snapshot_directory))
-        throw error(source_subvolume, DIRECTORY_ABS);
-
-      this->snapshot_directory = snapshot_directory;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_snapshot_name () const
-    {
-      return this->snapshot_name;
     }
-
-    void
-    btrfs_snapshot::set_snapshot_name (std::string const& snapshot_name)
-    {
-      if (!is_absname(snapshot_name))
-        throw error(source_subvolume, DIRECTORY_ABS);
-
-      this->snapshot_name = snapshot_name;
-    }
-
-    std::string const&
-    btrfs_snapshot::get_chroot_type () const
-    {
-      static const std::string type("btrfs-snapshot");
-
-      return type;
-    }
-
-    std::string
-    btrfs_snapshot::get_path () const
-    {
-      return get_mount_location();
-    }
-
-    void
-    btrfs_snapshot::setup_env (chroot const& chroot,
-                               environment&  env) const
-    {
-      chroot::setup_env(chroot, env);
-
-      env.add("CHROOT_BTRFS_SOURCE_SUBVOLUME", get_source_subvolume());
-      env.add("CHROOT_BTRFS_SNAPSHOT_DIRECTORY", get_snapshot_directory());
-      env.add("CHROOT_BTRFS_SNAPSHOT_NAME", get_snapshot_name());
-    }
-
-    void
-    btrfs_snapshot::setup_lock (chroot::setup_type type,
-                                bool               lock,
-                                int                status)
-    {
-      /* Create or unlink session information. */
-      if ((type == SETUP_START && lock == true) ||
-          (type == SETUP_STOP && lock == false && status == 0))
-        {
-          bool start = (type == SETUP_START);
-          setup_session_info(start);
-        }
-    }
-
-    chroot::chroot::session_flags
-    btrfs_snapshot::get_session_flags (chroot const& chroot) const
-    {
-      session_flags flags = SESSION_NOFLAGS;
-
-      if (get_facet<facet::session>())
-        flags = flags | SESSION_PURGE;
-
-      return flags;
-    }
-
-    void
-    btrfs_snapshot::get_details (chroot const& chroot,
-                                 format_detail& detail) const
-    {
-      chroot::get_details(chroot, detail);
-
-      if (!this->get_source_subvolume().empty())
-        detail.add(_("Btrfs Source Subvolume"), get_source_subvolume());
-      if (!this->get_snapshot_directory().empty())
-        detail.add(_("Btrfs Snapshot Directory"), get_snapshot_directory());
-      if (!this->get_snapshot_name().empty())
-        detail.add(_("Btrfs Snapshot Name"), get_snapshot_name());
-    }
-
-    void
-    btrfs_snapshot::get_used_keys (string_list& used_keys) const
-    {
-      chroot::get_used_keys(used_keys);
-
-      used_keys.push_back("btrfs-source-subvolume");
-      used_keys.push_back("btrfs-snapshot-directory");
-      used_keys.push_back("btrfs-snapshot-name");
-    }
-
-    void
-    btrfs_snapshot::get_keyfile (chroot const& chroot,
-                                 keyfile& keyfile) const
-    {
-      chroot::get_keyfile(chroot, keyfile);
-
-      bool issession = static_cast<bool>(get_facet<facet::session>());
-
-      if (!issession)
-        keyfile::set_object_value(*this,
-                                  &btrfs_snapshot::get_source_subvolume,
-                                  keyfile, get_name(),
-                                  "btrfs-source-subvolume");
-
-      if (!issession)
-        keyfile::set_object_value(*this,
-                                  &btrfs_snapshot::get_snapshot_directory,
-                                  keyfile, get_name(),
-                                  "btrfs-snapshot-directory");
-
-      if (issession)
-        keyfile::set_object_value(*this,
-                                  &btrfs_snapshot::get_snapshot_name,
-                                  keyfile, get_name(),
-                                  "btrfs-snapshot-name");
-    }
-
-    void
-    btrfs_snapshot::set_keyfile (chroot&        chroot,
-                                 keyfile const& keyfile)
-    {
-      chroot::set_keyfile(chroot, keyfile);
-
-      bool issession = static_cast<bool>(get_facet<facet::session>());
-
-      keyfile::get_object_value(*this, &btrfs_snapshot::set_source_subvolume,
-                                keyfile, get_name(), "btrfs-source-subvolume",
-                                issession ?
-                                keyfile::PRIORITY_DISALLOWED :
-                                keyfile::PRIORITY_REQUIRED
-                                ); // Only needed for creating snapshot, not using snapshot
-
-      keyfile::get_object_value(*this, &btrfs_snapshot::set_snapshot_directory,
-                                keyfile, get_name(), "btrfs-snapshot-directory",
-                                issession ?
-                                keyfile::PRIORITY_DISALLOWED :
-                                keyfile::PRIORITY_REQUIRED
-                                ); // Only needed for creating snapshot, not using snapshot
-
-      keyfile::get_object_value(*this, &btrfs_snapshot::set_snapshot_name,
-                                keyfile, get_name(), "btrfs-snapshot-name",
-                                issession ?
-                                keyfile::PRIORITY_REQUIRED :
-                                keyfile::PRIORITY_DISALLOWED);
-    }
-
   }
 }
diff --git a/lib/sbuild/chroot/facet/btrfs-snapshot.h b/lib/sbuild/chroot/facet/btrfs-snapshot.h
index 81b64387..5f92c9ed 100644
--- a/lib/sbuild/chroot/facet/btrfs-snapshot.h
+++ b/lib/sbuild/chroot/facet/btrfs-snapshot.h
@@ -16,146 +16,163 @@
  *
  *********************************************************************/
 
-#ifndef SBUILD_CHROOT_BTRFS_SNAPSHOT_H
-#define SBUILD_CHROOT_BTRFS_SNAPSHOT_H
+#ifndef SBUILD_CHROOT_FACET_BTRFS_SNAPSHOT_H
+#define SBUILD_CHROOT_FACET_BTRFS_SNAPSHOT_H
 
 #include <sbuild/chroot/chroot.h>
+#include <sbuild/chroot/facet/storage.h>
 
 namespace sbuild
 {
   namespace chroot
   {
-    /**
-     * A chroot stored on an BTRFS logical volume (LV).
-     *
-     * A snapshot LV will be created and mounted on demand.
-     */
-    class btrfs_snapshot : public chroot
+    namespace facet
     {
-    protected:
-      /// The constructor.
-      btrfs_snapshot ();
-
-      /// The copy constructor.
-      btrfs_snapshot (const btrfs_snapshot& rhs);
-
-      friend class chroot;
-
-    public:
-      /// The destructor.
-      virtual ~btrfs_snapshot ();
-
-      virtual chroot::ptr
-      clone () const;
-
-      virtual chroot::ptr
-      clone_session (std::string const& session_id,
-                     std::string const& alias,
-                     std::string const& user,
-                     bool               root) const;
-
-      virtual chroot::ptr
-      clone_source () const;
-
-      /**
-       * Get the source subvolume path.  This is used by "btrfs
-       * subvolume snapshot".
-       *
-       * @returns the source subvolume.
-       */
-      std::string const&
-      get_source_subvolume () const;
 
       /**
-       * Set the source subvolume path.  This is used by "btrfs
-       * subvolume snapshot".
+       * A chroot stored on an BTRFS subvolume.
        *
-       * @param source_subvolume the source subvolume.
+       * A snapshot subvolume will be created and mounted on demand.
        */
-      void
-      set_source_subvolume (std::string const& source_subvolume);
-
-      /**
-       * Get the snapshot directory.
-       *
-       * @returns the directory.
-       */
-      std::string const&
-      get_snapshot_directory () const;
-
-      /**
-       * Set the snapshot directory.
-       *
-       * @param snapshot_directory the snapshot directory.
-       */
-      void
-      set_snapshot_directory (std::string const& snapshot_directory);
-
-      /**
-       * Get the snapshot name.  This is used by "btrfs subvolume
-       * snapshot", and is the full path to the snapshot.
-       *
-       * @returns the name.
-       */
-      std::string const&
-      get_snapshot_name () const;
-
-      /**
-       * Set the snapshot name.  This is used by "btrfs subvolume
-       * snapshot", and is the full path to the snapshot.
-       *
-       * @param snapshot_name the snapshot name.
-       */
-      void
-      set_snapshot_name (std::string const& snapshot_name);
-
-      virtual std::string const&
-      get_chroot_type () const;
-
-      virtual std::string
-      get_path () const;
-
-      virtual void
-      setup_env (chroot const& chroot,
-                 environment&  env) const;
-
-      virtual session_flags
-      get_session_flags (chroot const& chroot) const;
-
-    protected:
-      virtual void
-      setup_lock (chroot::setup_type type,
-                  bool               lock,
-                  int                status);
-
-      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:
-      /// Btrfs source subvolume
-      std::string source_subvolume;
-      /// Btrfs snapshot path
-      std::string snapshot_directory;
-      /// Btrfs snapshot name
-      std::string snapshot_name;
-    };
-
+      class btrfs_snapshot : public storage
+      {
+      public:
+        /// Exception type.
+        typedef chroot::error error;
+
+        /// A shared_ptr to a chroot facet object.
+        typedef std::shared_ptr<btrfs_snapshot> ptr;
+
+        /// A shared_ptr to a const chroot facet object.
+        typedef std::shared_ptr<const btrfs_snapshot> const_ptr;
+
+      protected:
+        /// The constructor.
+        btrfs_snapshot ();
+
+        /// The copy constructor.
+        btrfs_snapshot (const btrfs_snapshot& rhs);
+
+        void
+        set_chroot (chroot& chroot);
+
+        friend class chroot;
+
+      public:
+        /// The destructor.
+        virtual ~btrfs_snapshot ();
+
+        virtual std::string const&
+        get_name () const;
+
+        /**
+         * Create a chroot facet.
+         *
+         * @returns a shared_ptr to the new chroot facet.
+         */
+        static ptr
+        create ();
+
+        facet::ptr
+        clone () const;
+
+        /**
+         * Get the source subvolume path.  This is used by "btrfs
+         * subvolume snapshot".
+         *
+         * @returns the source subvolume.
+         */
+        std::string const&
+        get_source_subvolume () const;
+
+        /**
+         * Set the source subvolume path.  This is used by "btrfs
+         * subvolume snapshot".
+         *
+         * @param source_subvolume the source subvolume.
+         */
+        void
+        set_source_subvolume (std::string const& source_subvolume);
+
+        /**
+         * Get the snapshot directory.
+         *
+         * @returns the directory.
+         */
+        std::string const&
+        get_snapshot_directory () const;
+
+        /**
+         * Set the snapshot directory.
+         *
+         * @param snapshot_directory the snapshot directory.
+         */
+        void
+        set_snapshot_directory (std::string const& snapshot_directory);
+
+        /**
+         * Get the snapshot name.  This is used by "btrfs subvolume
+         * snapshot", and is the full path to the snapshot.
+         *
+         * @returns the name.
+         */
+        std::string const&
+        get_snapshot_name () const;
+
+        /**
+         * Set the snapshot name.  This is used by "btrfs subvolume
+         * snapshot", and is the full path to the snapshot.
+         *
+         * @param snapshot_name the snapshot name.
+         */
+        void
+        set_snapshot_name (std::string const& snapshot_name);
+
+        virtual std::string
+        get_path () const;
+
+        virtual void
+        setup_env (chroot const& chroot,
+                   environment&  env) const;
+
+        virtual chroot::session_flags
+        get_session_flags (chroot const& chroot) const;
+
+      protected:
+        virtual void
+        setup_lock (chroot::setup_type type,
+                    bool               lock,
+                    int                status);
+
+        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:
+        /// Btrfs source subvolume
+        std::string source_subvolume;
+        /// Btrfs snapshot path
+        std::string snapshot_directory;
+        /// Btrfs snapshot name
+        std::string snapshot_name;
+      };
+
+    }
   }
 }
 
-#endif /* SBUILD_CHROOT_BTRFS_SNAPSHOT_H */
+#endif /* SBUILD_CHROOT_FACET_BTRFS_SNAPSHOT_H */
 
 /*
  * Local Variables:
diff --git a/lib/sbuild/chroot/facet/session-clonable.cc b/lib/sbuild/chroot/facet/session-clonable.cc
index bc347631..6b6efc18 100644
--- a/lib/sbuild/chroot/facet/session-clonable.cc
+++ b/lib/sbuild/chroot/facet/session-clonable.cc
@@ -34,7 +34,7 @@
 #include <sbuild/chroot/loopback.h>
 #endif // SBUILD_FEATURE_LOOPBACK
 #ifdef SBUILD_FEATURE_BTRFSSNAP
-#include <sbuild/chroot/btrfs-snapshot.h>
+#include <sbuild/chroot/facet/btrfs-snapshot.h>
 #endif // SBUILD_FEATURE_BTRFSSNAP
 #ifdef SBUILD_FEATURE_UNION
 #include <sbuild/chroot/facet/fsunion.h>
@@ -192,12 +192,12 @@ namespace sbuild
 
 #ifdef SBUILD_FEATURE_BTRFSSNAP
         /* Btrfs snapshots need the snapshot name specifying. */
-        std::shared_ptr<btrfs_snapshot> btrfs_snapshot(std::dynamic_pointer_cast<btrfs_snapshot>(clone));
-        if (btrfs_snapshot && !btrfs_snapshot->get_snapshot_directory().empty())
+        btrfs_snapshot::ptr btrfs_snap(clone->get_facet<btrfs_snapshot>());
+        if (btrfs_snap && !btrfs_snap->get_snapshot_directory().empty())
           {
-            std::string snapname(btrfs_snapshot->get_snapshot_directory());
+            std::string snapname(btrfs_snap->get_snapshot_directory());
             snapname += "/" + clone->get_name();
-            btrfs_snapshot->set_snapshot_name(snapname);
+            btrfs_snap->set_snapshot_name(snapname);
           }
 #endif // SBUILD_FEATURE_BTRFSSNAP