summaryrefslogtreecommitdiffstats
path: root/libdb/db_store.c
diff options
context:
space:
mode:
Diffstat (limited to 'libdb/db_store.c')
-rw-r--r--libdb/db_store.c369
1 files changed, 369 insertions, 0 deletions
diff --git a/libdb/db_store.c b/libdb/db_store.c
new file mode 100644
index 0000000..062db71
--- /dev/null
+++ b/libdb/db_store.c
@@ -0,0 +1,369 @@
+/*
+ * db_store.c: dbstore(), database storage routine.
+ *
+ * Copyright (C) 1994, 1995 Graeme W. Wilford. (Wilf.)
+ * Copyright (C) 2001, 2002 Colin Watson.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * Mon Aug 8 20:35:30 BST 1994 Wilf. (G.Wilford@ee.surrey.ac.uk)
+ */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif /* HAVE_CONFIG_H */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "timespec.h"
+#include "xvasprintf.h"
+
+#include "gettext.h"
+#define _(String) gettext (String)
+
+#include "manconfig.h"
+
+#include "error.h"
+
+#include "mydbm.h"
+#include "db_storage.h"
+
+/* compare_ids(a,b) is negative if id 'a' is preferred to id 'b', i.e. if
+ * 'a' is a more canonical database entry than 'b'; positive if 'b' is
+ * preferred to 'a'; and zero if they are equivalent. This usually goes in
+ * comparison order, but there's a special exception when FAVOUR_STRAYCATS
+ * is set.
+ *
+ * If promote_links is true, consider SO_MAN equivalent to ULT_MAN. This is
+ * appropriate when sorting candidate pages for display.
+ */
+int compare_ids (char a, char b, int promote_links)
+{
+#ifdef FAVOUR_STRAYCATS
+ if (a == WHATIS_MAN && b == STRAY_CAT)
+ return 1;
+ else if (a == STRAY_CAT && b == WHATIS_MAN)
+ return -1;
+#endif
+
+ if (promote_links) {
+ if ((a == ULT_MAN && b == SO_MAN) ||
+ (a == SO_MAN && b == ULT_MAN))
+ return 0;
+ }
+
+ if (a < b)
+ return -1;
+ else if (a > b)
+ return 1;
+ else
+ return 0;
+}
+
+/* The do_we_replace logic. Decide, for some existing key, whether it should
+ * be replaced with some new contents. Check that names and section
+ * extensions match before calling this.
+ */
+static int replace_if_necessary (MYDBM_FILE dbf,
+ struct mandata *newdata,
+ struct mandata *olddata,
+ datum newkey, datum newcont)
+{
+ /* It's OK to replace ULT_MAN with SO_MAN if the mtime is newer. It
+ * isn't OK to replace a real page (either ULT_MAN or SO_MAN) with a
+ * whatis reference; if the real page really went away then
+ * purge_missing will catch that in time, but a real page that still
+ * exists should always take precedence.
+ */
+ if (compare_ids (newdata->id, olddata->id, 1) <= 0 &&
+ timespec_cmp (newdata->mtime, olddata->mtime) > 0) {
+ debug ("replace_if_necessary(): newer mtime; replacing\n");
+ if (MYDBM_REPLACE (dbf, newkey, newcont))
+ gripe_replace_key (MYDBM_DPTR (newkey));
+ return 0;
+ }
+
+ if (compare_ids (newdata->id, olddata->id, 0) < 0) {
+ if (MYDBM_REPLACE (dbf, newkey, newcont))
+ gripe_replace_key (MYDBM_DPTR (newkey));
+ return 0;
+ }
+
+ /* TODO: name fields should be collated with the requested name */
+
+ if (newdata->id == olddata->id) {
+ if (STREQ (dash_if_unset (newdata->comp), olddata->comp))
+ return 0; /* same file */
+ else {
+ debug ("ignoring differing compression "
+ "extensions: %s\n", MYDBM_DPTR (newkey));
+ return 1; /* differing exts */
+ }
+ }
+
+ debug ("ignoring differing ids: %s\n", MYDBM_DPTR (newkey));
+ return 0;
+}
+
+/* The complement of split_content */
+static datum make_content (struct mandata *in)
+{
+ datum cont;
+ static const char dash[] = "-";
+
+ memset (&cont, 0, sizeof cont);
+
+ if (!in->pointer)
+ in->pointer = dash;
+ if (!in->filter)
+ in->filter = dash;
+ if (!in->comp)
+ in->comp = dash;
+ if (!in->whatis)
+ in->whatis = dash + 1;
+
+ MYDBM_SET (cont, xasprintf (
+ "%s\t%s\t%s\t%ld\t%ld\t%c\t%s\t%s\t%s\t%s",
+ dash_if_unset (in->name),
+ in->ext,
+ in->sec,
+ (long) in->mtime.tv_sec,
+ (long) in->mtime.tv_nsec,
+ in->id,
+ in->pointer,
+ in->filter,
+ in->comp,
+ in->whatis));
+
+#ifdef NDBM
+ /* limit of 4096 bytes of data using ndbm */
+ if (MYDBM_DSIZE (cont) > 4095) {
+ MYDBM_DPTR (cont)[4095] = '\0';
+ MYDBM_DSIZE (cont) = 4096;
+ }
+#endif
+ return cont;
+}
+
+/*
+ Any one of three situations can occur when storing some data.
+
+ 1) no simple key is found.
+ store as singular reference.
+ 2) simple key already exists, content starts with a '\t'.
+ Already multiple reference. Add our new item in multiple format
+ and update the simple key content, to point to our new one also.
+ 3) simple key already exists, content does not start with a '\t'.
+ First we have to reformat the simple key into a multi key for the
+ old item, and insert. Then we have to insert the new data as a
+ multi key. Lastly we must create the simple key and do a replace
+ on it.
+
+ Use precedence algorithm on inserts. If we already have a key assigned
+ to the new value, check priority of page using id. If new page is higher
+ (lower value), replace old with new, otherwise ignore new page.
+
+ If we have two ULT_MAN pages competing for the same key, we must have
+ more than one of foo.sec, foo.sec.comp1, foo.sec.comp2. OR we have a
+ replacement page. If the mtimes differ, throw out the old struct and
+ replace it with the new, if the comp exts differ, oops, this is bad,
+ keep one and return appropriate error code.
+
+ If we have two WHATIS_MAN pages or a WHATIS_MAN and a SO_MAN page
+ competing for the same key, don't worry. This will happen a lot and is
+ not a problem.
+
+ return errorcode or 0 on success.
+*/
+int dbstore (MYDBM_FILE dbf, struct mandata *in, const char *base)
+{
+ datum oldkey, oldcont;
+
+ memset (&oldkey, 0, sizeof oldkey);
+ memset (&oldcont, 0, sizeof oldcont);
+
+ /* create a simple key */
+ MYDBM_SET (oldkey, name_to_key (base));
+ if (!*base) {
+ dbprintf (in);
+ return 2;
+ }
+
+ if (in->name) {
+ error (0, 0, "in->name (%s) should not be set when calling "
+ "dbstore()!\n",
+ in->name);
+ free (in->name);
+ in->name = NULL;
+ }
+
+ /* get the content for the simple key */
+
+ oldcont = MYDBM_FETCH (dbf, oldkey);
+
+ if (MYDBM_DPTR (oldcont) == NULL) { /* situation (1) */
+ if (!STREQ (base, MYDBM_DPTR (oldkey)))
+ in->name = xstrdup (base);
+ oldcont = make_content (in);
+ if (MYDBM_REPLACE (dbf, oldkey, oldcont))
+ gripe_replace_key (MYDBM_DPTR (oldkey));
+ MYDBM_FREE_DPTR (oldcont);
+ free (in->name);
+ in->name = NULL;
+ } else if (*MYDBM_DPTR (oldcont) == '\t') { /* situation (2) */
+ datum newkey, newcont;
+
+ memset (&newkey, 0, sizeof newkey);
+ memset (&newcont, 0, sizeof newcont);
+
+ newkey = make_multi_key (base, in->ext);
+ newcont = make_content (in);
+
+ /* Try to insert the new multi data */
+
+ if (MYDBM_INSERT (dbf, newkey, newcont)) {
+ datum cont;
+ struct mandata info;
+ int ret;
+
+ MYDBM_FREE_DPTR (oldcont);
+ cont = MYDBM_FETCH (dbf, newkey);
+ split_content (MYDBM_DPTR (cont), &info);
+ ret = replace_if_necessary (dbf, in, &info,
+ newkey, newcont);
+ /* MYDBM_FREE_DPTR (cont); */
+ free_mandata_elements (&info);
+ MYDBM_FREE_DPTR (newkey);
+ MYDBM_FREE_DPTR (newcont);
+ MYDBM_FREE_DPTR (oldkey);
+
+ return ret;
+ }
+
+ /* Now lets add some info to the simple key's cont. */
+
+ /* This next bit needs to be done first as we'll wipe out
+ MYDBM_DPTR (oldcont) otherwise (for NDBM only!) */
+
+ MYDBM_FREE_DPTR (newkey);
+ MYDBM_FREE_DPTR (newcont);
+
+ MYDBM_SET (newcont, xasprintf (
+ "%s\t%s\t%s", MYDBM_DPTR (oldcont), base, in->ext));
+ MYDBM_FREE_DPTR (oldcont);
+
+ /* Try to replace the old simple data with the new stuff */
+
+ if (MYDBM_REPLACE (dbf, oldkey, newcont))
+ gripe_replace_key (MYDBM_DPTR (oldkey));
+
+ MYDBM_FREE_DPTR (newcont);
+ } else { /* situation (3) */
+ datum newkey, newcont, lastkey, lastcont;
+ struct mandata old;
+ char *old_name;
+
+ memset (&newkey, 0, sizeof newkey);
+ memset (&newcont, 0, sizeof newcont);
+ memset (&lastkey, 0, sizeof lastkey);
+ memset (&lastcont, 0, sizeof lastcont);
+
+ /* Extract the old singular reference */
+
+ split_content (MYDBM_DPTR (oldcont), &old);
+
+ /* Create multi keys for both old
+ and new items, create new content */
+
+ if (old.name)
+ old_name = xstrdup (old.name);
+ else
+ old_name = xstrdup (MYDBM_DPTR (oldkey));
+
+ lastkey = make_multi_key (old_name, old.ext);
+
+ /* Check against identical multi keys before inserting
+ into db */
+
+ if (STREQ (old_name, base) && STREQ (old.ext, in->ext)) {
+ int ret;
+
+ if (!STREQ (base, MYDBM_DPTR (oldkey)))
+ in->name = xstrdup (base);
+ newcont = make_content (in);
+ ret = replace_if_necessary (dbf, in, &old,
+ oldkey, newcont);
+ /* MYDBM_FREE_DPTR (oldcont); */
+ free_mandata_elements (&old);
+ MYDBM_FREE_DPTR (newcont);
+ MYDBM_FREE_DPTR (lastkey);
+ MYDBM_FREE_DPTR (oldkey);
+ free (old_name);
+ free (in->name);
+ in->name = NULL;
+
+ return ret;
+ }
+
+ /* Multi keys use the proper case, and so don't need a name
+ * field.
+ */
+ if (old.name) {
+ free (old.name);
+ old.name = NULL;
+ }
+
+ lastcont = make_content (&old);
+
+ /* We always replace here; if the multi key already exists
+ * in the database, then that indicates some kind of
+ * database corruption, but our new multi key is almost
+ * certainly better.
+ */
+ if (MYDBM_REPLACE (dbf, lastkey, lastcont))
+ gripe_replace_key (MYDBM_DPTR (lastkey));
+
+ MYDBM_FREE_DPTR (lastkey);
+ MYDBM_FREE_DPTR (lastcont);
+
+ newkey = make_multi_key (base, in->ext);
+ newcont = make_content (in);
+
+ if (MYDBM_REPLACE (dbf, newkey, newcont))
+ gripe_replace_key (MYDBM_DPTR (newkey));
+
+ MYDBM_FREE_DPTR (newkey);
+ MYDBM_FREE_DPTR (newcont);
+
+ /* Now build a simple reference to the above two items */
+
+ MYDBM_SET (newcont, xasprintf (
+ "\t%s\t%s\t%s\t%s", old_name, old.ext, base, in->ext));
+
+ if (MYDBM_REPLACE (dbf, oldkey, newcont))
+ gripe_replace_key (MYDBM_DPTR (oldkey));
+
+ /* MYDBM_FREE_DPTR (oldcont); */
+ free_mandata_elements (&old);
+ MYDBM_FREE_DPTR (newcont);
+ free (old_name);
+ }
+
+ MYDBM_FREE_DPTR (oldkey);
+ return 0;
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-21 15:17:54 +0000