From 52970711cf974e7905a7fe1252be3bcffcd28d62 Mon Sep 17 00:00:00 2001 From: antirez Date: Sun, 26 Dec 2010 18:46:25 +0100 Subject: [PATCH] added diskstore.c, currently just a stub --- src/diskstore.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 110 insertions(+) create mode 100644 src/diskstore.c diff --git a/src/diskstore.c b/src/diskstore.c new file mode 100644 index 00000000..de0e9c3e --- /dev/null +++ b/src/diskstore.c @@ -0,0 +1,110 @@ +/* diskstore.c implements a very simple disk backed key-value store used + * by Redis for the "disk" backend. This implementation uses the filesystem + * to store key/value pairs. Every file represents a given key. + * + * The key path is calculated using the SHA1 of the key name. For instance + * the key "foo" is stored as a file name called: + * + * /0b/ee/0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a33 + * + * The couples of characters from the hex output of SHA1 are also used + * to locate two two levels of directories to store the file (as most + * filesystems are not able to handle too many files in a single dir). + * + * In the end there are 65536 final directories (256 directories inside + * every 256 top level directories), so that with 1 billion of files every + * directory will contain in the average 15258 entires, that is ok with + * most filesystems implementation. + * + * The actaul implementation of this disk store is highly related to the + * filesystem implementation. This implementation may be replaced by + * a B+TREE implementation in future implementations. + * + * Data ok every key is serialized using the same format used for .rdb + * serialization. Everything is serialized on every entry: key name, + * ttl information in case of keys with an associated expire time, and the + * serialized value itself. + * + * Because the format is the same of the .rdb files it is trivial to create + * an .rdb file starting from this format just by mean of scanning the + * directories and concatenating entries, with the sole addition of an + * .rdb header at the start and the end-of-db opcode at the end. + * + * ------------------------------------------------------------------------- + * + * Copyright (c) 2010-2011, Salvatore Sanfilippo + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of Redis nor the names of its contributors may be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#include "redis.h" + +#include +#include + +int dsOpen(void) { + struct stat sb; + int retval; + char *path = server.diskstore_path; + + if ((retval = stat(path,&sb) == -1) && errno != ENOENT) { + redisLog(REDIS_WARNING, "Error opening disk store at %s: %s", + path, strerror(errno)); + return REDIS_ERR; + } + + /* Directory already in place. Assume everything is ok. */ + if (retval == 0 && S_ISDIR(sb.st_mode)) return REDIS_OK; + + /* File exists but it's not a directory */ + if (retval == 0 && !S_ISDIR(sb.st_mode)) { + redisLog(REDIS_WARNING,"Disk store at %s is not a directory", path); + return REDIS_ERR; + } + + /* New disk store, create the directory structure now, as creating + * them in a lazy way is not a good idea, after very few insertions + * we'll need most of the 65536 directories anyway. */ + if (mkdir(path) == -1) { + redisLog(REDIS_WARNING,"Disk store init failed creating dir %s: %s", + path, strerror(errno)); + return REDIS_ERR; + } + return REDIS_OK; +} + +int dsClose(void) { + return REDIS_OK; +} + +int dsSet(redisDb *db, robj *key, robj *val) { +} + +robj *dsGet(redisDb *db, robj *key) { +} + +int dsExists(redisDb *db, robj *key) { +} -- GitLab