database: add gdbm backend

src/pulsecore/database-gdbm.c

@@ -0,0 +1,246 @@
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2009 Lennart Poettering
+
+  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, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#include <errno.h>
+#include <gdbm.h>
+
+#include <pulse/xmalloc.h>
+#include <pulsecore/core-util.h>
+#include <pulsecore/log.h>
+
+#include "database.h"
+
+#define MAKE_GDBM_FILE(x) ((GDBM_FILE) (x))
+
+static inline datum* datum_to_gdbm(datum *to, const pa_datum *from) {
+    pa_assert(from);
+    pa_assert(to);
+
+    to->dptr = from->data;
+    to->dsize = from->size;
+
+    return to;
+}
+
+static inline pa_datum* datum_from_gdbm(pa_datum *to, const datum *from) {
+    pa_assert(from);
+    pa_assert(to);
+
+    to->data = from->dptr;
+    to->size = from->dsize;
+
+    return to;
+}
+
+void pa_datum_free(pa_datum *d) {
+    pa_assert(d);
+
+    free(d->data); /* gdbm uses raw malloc/free hence we should do that here, too */
+    pa_zero(d);
+}
+
+pa_database* pa_database_open(const char *fn, pa_bool_t for_write) {
+    GDBM_FILE f;
+    int gdbm_cache_size;
+    char *path;
+
+    pa_assert(fn);
+
+    /* We include the host identifier in the file name because gdbm
+     * files are CPU dependant, and we don't want things to go wrong
+     * if we are on a multiarch system. */
+
+    path = pa_sprintf_malloc("%s."CANONICAL_HOST".gdbm", fn);
+    errno = 0;
+    f = gdbm_open((char*) path, 0, GDBM_NOLOCK | (for_write ? GDBM_WRCREAT : GDBM_READER), 0644, NULL);
+
+    if (f)
+        pa_log_debug("Opened GDBM database '%s'", path);
+
+    pa_xfree(path);
+
+    if (!f) {
+        if (errno == 0)
+            errno = EIO;
+        return NULL;
+    }
+
+    /* By default the cache of gdbm is rather large, let's reduce it a bit to save memory */
+    gdbm_cache_size = 10;
+    gdbm_setopt(f, GDBM_CACHESIZE, &gdbm_cache_size, sizeof(gdbm_cache_size));
+
+    return (pa_database*) f;
+}
+
+void pa_database_close(pa_database *db) {
+    pa_assert(db);
+
+    gdbm_close(MAKE_GDBM_FILE(db));
+}
+
+pa_datum* pa_database_get(pa_database *db, const pa_datum *key, pa_datum* data) {
+    datum gdbm_key, gdbm_data;
+
+    pa_assert(db);
+    pa_assert(key);
+    pa_assert(data);
+
+    gdbm_data = gdbm_fetch(MAKE_GDBM_FILE(db), *datum_to_gdbm(&gdbm_key, key));
+
+    return gdbm_data.dptr ?
+        datum_from_gdbm(data, &gdbm_data) :
+        NULL;
+}
+
+int pa_database_set(pa_database *db, const pa_datum *key, const pa_datum* data, pa_bool_t overwrite) {
+    datum gdbm_key, gdbm_data;
+
+    pa_assert(db);
+    pa_assert(key);
+    pa_assert(data);
+
+    return gdbm_store(MAKE_GDBM_FILE(db),
+                      *datum_to_gdbm(&gdbm_key, key),
+                      *datum_to_gdbm(&gdbm_data, data),
+                      overwrite ? GDBM_REPLACE : GDBM_INSERT) != 0 ? -1 : 0;
+}
+
+int pa_database_unset(pa_database *db, const pa_datum *key) {
+    datum gdbm_key;
+
+    pa_assert(db);
+    pa_assert(key);
+
+    return gdbm_delete(MAKE_GDBM_FILE(db), *datum_to_gdbm(&gdbm_key, key)) != 0 ? -1 : 0;
+}
+
+int pa_database_clear(pa_database *db) {
+    datum gdbm_key;
+
+    pa_assert(db);
+
+    gdbm_key = gdbm_firstkey(MAKE_GDBM_FILE(db));
+
+    while (gdbm_key.dptr) {
+        datum next;
+
+        next = gdbm_nextkey(MAKE_GDBM_FILE(db), gdbm_key);
+
+        gdbm_delete(MAKE_GDBM_FILE(db), gdbm_key);
+
+        free(gdbm_key.dptr);
+        gdbm_key = next;
+    }
+
+    return gdbm_reorganize(MAKE_GDBM_FILE(db)) == 0 ? 0 : -1;
+}
+
+signed pa_database_size(pa_database *db) {
+    datum gdbm_key;
+    unsigned n = 0;
+
+    pa_assert(db);
+
+    /* This sucks */
+
+    gdbm_key = gdbm_firstkey(MAKE_GDBM_FILE(db));
+
+    while (gdbm_key.dptr) {
+        datum next;
+
+        n++;
+
+        next = gdbm_nextkey(MAKE_GDBM_FILE(db), gdbm_key);
+        free(gdbm_key.dptr);
+        gdbm_key = next;
+    }
+
+    return (signed) n;
+}
+
+pa_datum* pa_database_first(pa_database *db, pa_datum *key, pa_datum *data) {
+    datum gdbm_key, gdbm_data;
+
+    pa_assert(db);
+    pa_assert(key);
+
+    gdbm_key = gdbm_firstkey(MAKE_GDBM_FILE(db));
+
+    if (!gdbm_key.dptr)
+        return NULL;
+
+    if (data) {
+        gdbm_data = gdbm_fetch(MAKE_GDBM_FILE(db), gdbm_key);
+
+        if (!gdbm_data.dptr) {
+            free(gdbm_key.dptr);
+            return NULL;
+        }
+
+        datum_from_gdbm(data, &gdbm_data);
+    }
+
+    datum_from_gdbm(key, &gdbm_key);
+
+    return key;
+}
+
+pa_datum* pa_database_next(pa_database *db, const pa_datum *key, pa_datum *next, pa_datum *data) {
+    datum gdbm_key, gdbm_data;
+
+    pa_assert(db);
+    pa_assert(key);
+    pa_assert(next);
+
+    if (!key)
+        return pa_database_first(db, next, data);
+
+    gdbm_key = gdbm_nextkey(MAKE_GDBM_FILE(db), *datum_to_gdbm(&gdbm_key, key));
+
+    if (!gdbm_key.dptr)
+        return NULL;
+
+    if (data) {
+        gdbm_data = gdbm_fetch(MAKE_GDBM_FILE(db), gdbm_key);
+
+        if (!gdbm_data.dptr) {
+            free(gdbm_key.dptr);
+            return NULL;
+        }
+
+        datum_from_gdbm(data, &gdbm_data);
+    }
+
+    datum_from_gdbm(next, &gdbm_key);
+
+    return next;
+}
+
+int pa_database_sync(pa_database *db) {
+    pa_assert(db);
+
+    gdbm_sync(MAKE_GDBM_FILE(db));
+    return 0;
+}