-
/*
- * $Id: StoreFileSystem.h,v 1.1 2003/07/22 15:23:01 robertc Exp $
- *
- * SQUID Web Proxy Cache http://www.squid-cache.org/
- * ----------------------------------------------------------
- *
- * Squid is the result of efforts by numerous individuals from
- * the Internet community; see the CONTRIBUTORS file for full
- * details. Many organizations have provided support for Squid's
- * development; see the SPONSORS file for full details. Squid is
- * Copyrighted (C) 2001 by the Regents of the University of
- * California; see the COPYRIGHT file for full details. Squid
- * incorporates software developed and/or copyrighted by other
- * sources; see the CREDITS file for full details.
+ * Copyright (C) 1996-2020 The Squid Software Foundation and contributors
*
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 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 General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
- *
- * Copyright (c) 2003, Robert Collins <robertc@squid-cache.org>
+ * Squid software is distributed under GPLv2+ license and includes
+ * contributions from numerous individuals and organizations.
+ * Please see the COPYING and CONTRIBUTORS files for details.
*/
#ifndef SQUID_STOREFILESYSTEM_H
#define SQUID_STOREFILESYSTEM_H
-#include "squid.h"
-#include "Array.h"
+#include "store/forward.h"
+#include <vector>
+
+/* ****** DOCUMENTATION ***** */
+/**
+ \defgroup FileSystems Storage Filesystems
+ *
+ \section FileSystemsIntroduction Introduction
+ \par
+ * Traditionally, Squid has always used the Unix filesystem (\link UFS UFS\endlink)
+ * to store cache objects on disk. Over the years, the
+ * poor performance of \link UFS UFS\endlink has become very obvious. In most
+ * cases, \link UFS UFS\endlink limits Squid to about 30-50 requests per second.
+ * Our work indicates that the poor performance is mostly
+ * due to the synchronous nature of open() and unlink()
+ * system calls, and perhaps thrashing of inode/buffer caches.
+ *
+ \par
+ * We want to try out our own, customized filesystems with Squid.
+ * In order to do that, we need a well-defined interface
+ * for the bits of Squid that access the permanent storage
+ * devices. We also require tighter control of the replacement
+ * policy by each storage module, rather than a single global
+ * replacement policy.
+ *
+ \section BuildStructure Build structure
+ \par
+ * The storage types live in \em src/fs/. Each subdirectory corresponds
+ * to the name of the storage type. When a new storage type is implemented
+ * configure.ac must be updated to autogenerate a Makefile in
+ * \em src/fs/foo/ from a Makefile.in file.
+ *
+ \todo DOCS: add template addition to configure.ac for storage module addition.
+ \todo DOCS: add template Makefile.am for storage module addition.
+ *
+ \par
+ * configure will take a list of storage types through the
+ * --enable-store-io parameter. This parameter takes a list of
+ * space separated storage types. For example,
+ * --enable-store-io="ufs aufs" .
+ *
+ \par
+ * Each storage type must create an archive file
+ * in \em src/fs/foo/.a . This file is automatically linked into
+ * squid at compile time.
+ *
+ \par
+ * Each storage filesystem must inherit from StoreFileSystem and provide
+ * all virtual function hooks for squid to operate with.
+ *
+ \section OperationOfStorageModules Operation of a Storage Module
+ \par
+ * Squid understands the concept of multiple diverse storage directories.
+ * Each storage directory provides a caching object store, with object
+ * storage, retrieval, indexing and replacement.
+ *
+ \par
+ * Each open object has associated with it a storeIOState object. The
+ * storeIOState object is used to record the state of the current
+ * object. Each storeIOState can have a storage module specific data
+ * structure containing information private to the storage module.
+ *
+ \par
+ * Each SwapDir has the concept of a maximum object size. This is used
+ * as a basic hint to the storage layer in first choosing a suitable
+ * SwapDir. The checkobj function is then called for suitable
+ * candidate SwapDirs to find out whether it wants to store a
+ * given StoreEntry. A maxobjsize of -1 means 'any size'.
+ */
+
+/**
+ \ingroup FileSystems
+ *
+ * The core API for storage modules this class provides all the hooks
+ * squid uses to interact with a filesystem IO module.
+ */
class StoreFileSystem
{
static void SetupAllFs();
static void FsAdd(StoreFileSystem &);
static void FreeAllFs();
- static Vector<StoreFileSystem*> const &FileSystems();
- typedef Vector<StoreFileSystem*>::iterator iterator;
- typedef Vector<StoreFileSystem*>::const_iterator const_iterator;
- StoreFileSystem() : initialised (false) {}
+ static std::vector<StoreFileSystem*> const &FileSystems();
+ typedef std::vector<StoreFileSystem*>::iterator iterator;
+ typedef std::vector<StoreFileSystem*>::const_iterator const_iterator;
+ StoreFileSystem() : initialised(false) {}
- virtual ~StoreFileSystem(){}
+ virtual ~StoreFileSystem() {}
virtual char const *type () const = 0;
virtual SwapDir *createSwapDir() = 0;
protected:
bool initialised;
+ virtual void registerWithCacheManager(void);
private:
- static Vector<StoreFileSystem*> &GetFileSystems();
- static Vector<StoreFileSystem*> *_FileSystems;
+ static std::vector<StoreFileSystem*> &GetFileSystems();
+ static std::vector<StoreFileSystem*> *_FileSystems;
+ static void RegisterAllFsWithCacheManager(void);
};
+// TODO: Kill this typedef!
typedef StoreFileSystem storefs_entry_t;
-
#endif /* SQUID_STOREFILESYSTEM_H */
+
projects / thirdparty / squid.git / blobdiff