database: extract common method to handle machine id and architecture

Part-of: <https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/425>

src/pulsecore/database.c

@@ -0,0 +1,72 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2020 Igor V. Kovalenko <igor.v.kovalenko@gmail.com>
+
+  PulseAudio 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.
+
+  PulseAudio 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 PulseAudio; if not, see <http://www.gnu.org/licenses/>.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+
+#include <pulse/xmalloc.h>
+#include <pulsecore/core-util.h>
+#include <pulsecore/log.h>
+
+#include "database.h"
+#include "core-error.h"
+
+pa_database* pa_database_open(const char *path, const char *fn, bool prependmid, bool for_write) {
+
+    const char *arch_suffix = pa_database_get_arch_suffix();
+    const char *filename_suffix = pa_database_get_filename_suffix();
+
+    char *machine_id = NULL, *filename_prefix, *full_path;
+
+    pa_database *f;
+
+    pa_assert(!arch_suffix || arch_suffix[0]);
+    pa_assert(filename_suffix && filename_suffix[0]);
+
+    if (prependmid && !(machine_id = pa_machine_id())) {
+        return NULL;
+    }
+
+    /* We include the host identifier in the file name because some database files are
+     * CPU dependent, and we don't want things to go wrong if we are on a multiarch system. */
+    filename_prefix = pa_sprintf_malloc("%s%s%s%s%s",
+            machine_id?:"", machine_id?"-":"",
+            fn,
+            arch_suffix?".":"", arch_suffix?:"");
+
+    full_path = pa_sprintf_malloc("%s" PA_PATH_SEP "%s%s", path, filename_prefix, filename_suffix);
+
+    f = pa_database_open_internal(full_path, for_write);
+
+    if (f)
+        pa_log_info("Successfully opened '%s' database file '%s'.", fn, full_path);
+    else
+        pa_log("Failed to open '%s' database file '%s': %s", fn, full_path, pa_cstrerror(errno));
+
+    pa_xfree(full_path);
+    pa_xfree(filename_prefix);
+
+    /* deallocate machine_id if it was used to construct file name */
+    pa_xfree(machine_id);
+
+    return f;
+}