compat: add tdestroy()

This adds a thread-safe tdestroy() replacement for systems without it
but with tfind(). This should fix linking failures on BSD.

(cherry picked from commit 320938b4bf)
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

compat/tdestroy.c

@@ -0,0 +1,100 @@
+/**
+ * @file tdestroy.c
+ * @brief replacement for GNU tdestroy()
+ */
+/*****************************************************************************
+ * Copyright (C) 2009, 2018 Rémi Denis-Courmont
+ *
+ * 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 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+#include <stdlib.h>
+#ifdef HAVE_SEARCH_H
+# include <search.h>
+#endif
+
+#ifdef HAVE_TFIND
+static __thread struct
+{
+    const void **tab;
+    size_t count;
+} list = { NULL, 0 };
+
+static void list_nodes(const void *node, const VISIT which, const int depth)
+{
+    (void) depth;
+
+    if (which != postorder && which != leaf)
+        return;
+
+    const void **tab = realloc(list.tab, sizeof (*tab) * (list.count + 1));
+    if (tab == NULL)
+        abort();
+
+    tab[list.count] = *(const void **)node;
+    list.tab = tab;
+    list.count++;
+}
+
+static __thread const void *smallest;
+
+static int cmp_smallest(const void *a, const void *b)
+{
+    if (a == b)
+        return 0;
+    if (a == smallest)
+        return -1;
+    if (b == smallest)
+        return +1;
+    abort();
+}
+
+void tdestroy(void *root, void (*freenode)(void *))
+{
+    const void **tab;
+    size_t count;
+
+    assert(freenode != NULL);
+
+    /* Enumerate nodes in order */
+    assert(list.count == 0);
+    twalk(root, list_nodes);
+    tab = list.tab;
+    count = list.count;
+    list.tab = NULL;
+    list.count = 0;
+
+    /* Destroy the tree */
+    for (size_t i = 0; i < count; i++)
+    {
+         void *node = (void *)(tab[i]);
+
+         smallest = node;
+         node = tdelete(node, &root, cmp_smallest);
+         assert(node != NULL);
+    }
+    assert (root == NULL);
+
+    /* Destroy the nodes */
+    for (size_t i = 0; i < count; i++)
+         freenode((void *)(tab[i]));
+    free(tab);
+}
+#endif /* HAVE_TFIND */

configure.ac

@@ -591,7 +591,7 @@ need_libc=false
 
 dnl Check for usual libc functions
 AC_CHECK_FUNCS([accept4 daemon fcntl flock fstatvfs fork getenv getpwuid_r isatty lstat memalign mkostemp mmap open_memstream openat pipe2 pread posix_fadvise posix_madvise posix_memalign setlocale stricmp strnicmp strptime tdestroy uselocale])
-AC_REPLACE_FUNCS([aligned_alloc atof atoll dirfd fdopendir ffsll flockfile fsync getdelim getpid lldiv memrchr nrand48 poll recvmsg rewind sendmsg setenv strcasecmp strcasestr strdup strlcpy strndup strnlen strnstr strsep strtof strtok_r strtoll swab tfind timegm timespec_get strverscmp pathconf])
+AC_REPLACE_FUNCS([aligned_alloc atof atoll dirfd fdopendir ffsll flockfile fsync getdelim getpid lldiv memrchr nrand48 poll recvmsg rewind sendmsg setenv strcasecmp strcasestr strdup strlcpy strndup strnlen strnstr strsep strtof strtok_r strtoll swab tdestroy tfind timegm timespec_get strverscmp pathconf])
 AC_REPLACE_FUNCS([gettimeofday])
 AC_CHECK_FUNC(fdatasync,,
   [AC_DEFINE(fdatasync, fsync, [Alias fdatasync() to fsync() if missing.])

include/vlc_fixups.h

@@ -480,12 +480,11 @@ void *tsearch( const void *key, void **rootp, int(*cmp)(const void *, const void
 void *tfind( const void *key, const void **rootp, int(*cmp)(const void *, const void *) );
 void *tdelete( const void *key, void **rootp, int(*cmp)(const void *, const void *) );
 void twalk( const void *root, void(*action)(const void *nodep, VISIT which, int depth) );
+#endif /* HAVE_SEARCH_H */
+#ifndef HAVE_TDESTROY
 void tdestroy( void *root, void (*free_node)(void *nodep) );
-#else // HAVE_SEARCH_H
-# ifndef HAVE_TDESTROY
 void vlc_tdestroy( void *, void (*)(void *) );
-#  define tdestroy vlc_tdestroy
-# endif
+# define tdestroy vlc_tdestroy
 #endif
 
 /* Random numbers */