libpriv: Add RpmOstreeRefTs and API to create one from a commit

This API is intended for use by the caching framework to hold open an
rpmdb for the previous commit.

Makefile-libpriv.am

@@ -26,6 +26,8 @@ librpmostreepriv_la_SOURCES = \
 	src/libpriv/rpmostree-util.h \
 	src/libpriv/rpmostree-passwd-util.c \
 	src/libpriv/rpmostree-passwd-util.h \
+	src/libpriv/rpmostree-refts.h \
+	src/libpriv/rpmostree-refts.c \
 	src/libpriv/rpmostree-refsack.h \
 	src/libpriv/rpmostree-refsack.c \
 	src/libpriv/rpmostree-cleanup.h \

src/libpriv/rpmostree-refts.c

@@ -0,0 +1,64 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2015 Colin Walters <walters@verbum.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published
+ * by the Free Software Foundation; either version 2 of the licence or (at
+ * your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General
+ * Public License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include <string.h>
+#include "rpmostree-refts.h"
+#include "rpmostree-rpm-util.h"
+
+/*
+ * A wrapper for an `rpmts` that supports:
+ *
+ *  - Reference counting
+ *  - Possibly holding a pointer to a tempdir, and cleaning it when unref'd
+ */
+
+RpmOstreeRefTs *
+rpmostree_refts_new (rpmts ts, int temp_base_dfd, const char *temp_path)
+{
+  RpmOstreeRefTs *rts = g_new0 (RpmOstreeRefTs, 1);
+  rts->ts = ts;
+  rts->refcount = 1;
+  rts->temp_base_dfd = temp_base_dfd;
+  rts->temp_path = g_strdup (temp_path);
+  return rts;
+}
+
+RpmOstreeRefTs *
+rpmostree_refts_ref (RpmOstreeRefTs *rts)
+{
+  g_atomic_int_inc (&rts->refcount);
+  return rts;
+}
+
+void
+rpmostree_refts_unref (RpmOstreeRefTs *rts)
+{
+  if (!g_atomic_int_dec_and_test (&rts->refcount))
+    return;
+  rpmtsFree (rts->ts);
+  
+  if (rts->temp_path)
+    (void) glnx_shutil_rm_rf_at (rts->temp_base_dfd, rts->temp_path, NULL, NULL);
+
+  g_free (rts->temp_path);
+  g_free (rts);
+}

src/libpriv/rpmostree-refts.h

@@ -0,0 +1,45 @@
+/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
+ *
+ * Copyright (C) 2015 Red Hat, In.c
+ *
+ * Licensed under the GNU Lesser General Public License Version 2.1
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#pragma once
+
+#include <hawkey/package.h>
+#include <hawkey/sack.h>
+#include "rpmostree-cleanup.h"
+
+typedef struct {
+  volatile gint refcount;
+  rpmts ts;
+  int temp_base_dfd;
+  char *temp_path;
+} RpmOstreeRefTs;
+
+RpmOstreeRefTs *
+rpmostree_refts_new (rpmts ts, int temp_base_dfd, const char *temp_path);
+
+RpmOstreeRefTs *
+rpmostree_refts_ref (RpmOstreeRefTs *rts);
+
+void
+rpmostree_refts_unref (RpmOstreeRefTs *rts);
+
+G_DEFINE_AUTOPTR_CLEANUP_FUNC(RpmOstreeRefTs, rpmostree_refts_unref);
+

src/libpriv/rpmostree-rpm-util.c

@@ -869,6 +869,38 @@ rpmostree_get_refsack_for_commit (OstreeRepo                *repo,
   return ret;
 }
 
+gboolean
+rpmostree_get_refts_for_commit (OstreeRepo                *repo,
+                                const char                *ref,
+                                RpmOstreeRefTs           **out_ts,
+                                GCancellable              *cancellable,
+                                GError                   **error)
+{
+  gboolean ret = FALSE;
+  g_autofree char *tempdir = NULL;
+  rpmts ts;
+  int r;
+  
+  if (!rpmostree_checkout_only_rpmdb_tempdir (repo, ref, &tempdir, NULL,
+                                              cancellable, error))
+    goto out;
+
+  ts = rpmtsCreate ();
+  /* This actually makes sense because we know we've verified it at build time */
+  rpmtsSetVSFlags (ts, _RPMVSF_NODIGESTS | _RPMVSF_NOSIGNATURES);
+
+  r = rpmtsSetRootDir (ts, tempdir);
+  g_assert_cmpint (r, ==, 0);
+  
+  ret = TRUE;
+  *out_ts = rpmostree_refts_new (ts, AT_FDCWD, tempdir);
+  g_clear_pointer (&tempdir, g_free);
+ out:
+  if (tempdir)
+    (void) glnx_shutil_rm_rf_at (AT_FDCWD, tempdir, NULL, NULL);
+  return ret;
+}
+
 gboolean
 rpmostree_get_pkglist_for_root (int               dfd,
                                 const char       *path,

src/libpriv/rpmostree-rpm-util.h

@@ -26,6 +26,7 @@
 #include <rpm/rpmlog.h>
 #include "rpmostree-util.h"
 #include "rpmostree-refsack.h"
+#include "rpmostree-refts.h"
 #include "rpmostree-cleanup.h"
 
 #include "libglnx.h"
@@ -101,6 +102,13 @@ rpmostree_get_refsack_for_root (int              dfd,
                                 GCancellable    *cancellable,
                                 GError         **error);
 
+gboolean
+rpmostree_get_refts_for_commit (OstreeRepo                *repo,
+                                const char                *ref,
+                                RpmOstreeRefTs           **out_ts,
+                                GCancellable              *cancellable,
+                                GError                   **error);
+
 gboolean
 rpmostree_get_pkglist_for_root (int               dfd,
                                 const char       *path,