journal: implement generic sharable mmap caching logic

instead of having one simple per-file cache implement an more
comprehensive one that works for multiple files and can actually
maintain multiple maps per file and per object type.

1 files changed, 34 insertions, 0 deletions

diff --git a/src/journal/mmap-cache.h b/src/journal/mmap-cache.h
new file mode 100644
index 0000000000..0a88fc584f
--- /dev/null
+++ b/src/journal/mmap-cache.h
@@ -0,0 +1,34 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+#pragma once
+
+/***
+  This file is part of systemd.
+
+  Copyright 2012 Lennart Poettering
+
+  systemd 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.
+
+  systemd 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 systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <inttypes.h>
+
+typedef struct MMapCache MMapCache;
+
+MMapCache* mmap_cache_new(unsigned contexts_max, unsigned fds_max);
+MMapCache* mmap_cache_ref(MMapCache *m);
+MMapCache* mmap_cache_unref(MMapCache *m);
+
+int mmap_cache_get(MMapCache *m, int fd, int prot, unsigned context, uint64_t offset, uint64_t size, void **ret);
+void mmap_cache_close_fd(MMapCache *m, int fd);
+void mmap_cache_close_context(MMapCache *m, unsigned context);