WIP: Low level file management
We have 'File' which associates a name with a file and will be used to offer an interface for the application. Posix 'Filehandles' which are managed in a 'Filehandlecache' to utilize a limited number of fd's at optimum. Internally we use 'Filedescriptor's which manage files, mapping and all kinds of metadata. Filedescriptors weak referenced by a registry and freed when the last user vanishes.
This commit is contained in:
Christian Thaeter
parent
94e075d2c2
commit
791f42c104
8 changed files with 649 additions and 8 deletions
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@ -31,12 +31,11 @@ liblumibackend_a_SOURCES = \
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# $(liblumibackend_a_srcdir)/filehandlecache.c
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noinst_HEADERS += \
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$(liblumibackend_a_srcdir)/mediaaccessfacade.cpp
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# $(liblumibackend_a_srcdir)/backend.h \
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# $(liblumibackend_a_srcdir)/file.h \
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# $(liblumibackend_a_srcdir)/filehandle.h \
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# $(liblumibackend_a_srcdir)/filedescriptor.h \
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# $(liblumibackend_a_srcdir)/filehandlecache.h
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noinst_HEADERS += \
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$(liblumibackend_a_srcdir)/mediaaccessfacade.cpp \
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$(liblumibackend_a_srcdir)/backend.h \
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$(liblumibackend_a_srcdir)/file.h \
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$(liblumibackend_a_srcdir)/filehandle.h \
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$(liblumibackend_a_srcdir)/filedescriptor.h \
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$(liblumibackend_a_srcdir)/filehandlecache.h
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64
src/backend/file.c
Normal file
64
src/backend/file.c
Normal file
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@ -0,0 +1,64 @@
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/*
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file.c - file handling
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "lib/mutex.h"
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#include "lib/safeclib.h"
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#include "backend/file.h"
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#include "backend/filedescriptor.h"
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#include <limits.h>
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NOBUG_DEFINE_FLAG (lumiera_file);
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LumieraFile
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lumiera_file_init (LumieraFile self, const char* name, int flags)
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{
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if (!lumiera_filedescriptor_acquire (&self->descriptor, name, flags))
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return NULL;
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self->name = lumiera_strndup (name, PATH_MAX);
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return self;
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}
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LumieraFile
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lumiera_file_destroy (LumieraFile self)
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{
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lumiera_reference_destroy (&self->descriptor);
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free ((void*)self->name);
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return self;
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}
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LumieraFile
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lumiera_file_new (const char* name, int flags)
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{
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LumieraFile self = lumiera_malloc (sizeof (lumiera_file));
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return lumiera_file_init (self, name, flags);
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}
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void
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lumiera_file_delete (LumieraFile self)
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{
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free (lumiera_file_destroy (self));
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}
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90
src/backend/file.h
Normal file
90
src/backend/file.h
Normal file
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@ -0,0 +1,90 @@
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/*
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file.h - interface to files by filename
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef LUMIERA_FILE_H
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#define LUMIERA_FILE_H
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#include "lib/mutex.h"
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#include "lib/llist.h"
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#include "lib/error.h"
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#include "lib/references.h"
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/**
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* @file File management
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* Handling Files is splitted into different classes:
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* 1. The 'lumiera_file' class which acts as interface to the outside for managing files.
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* 'lumiera_file' is addressed by the name of the file. Since files can have more than one name (hardlinks)
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* many 'lumiera_file' can point to a single 'lumiera_filedescriptor'
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* 2. The 'lumiera_filedescriptor' class which does the real work managing the file in the back.
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* 3. Since OS-filehandles are a limited resource we access the lazily as 'lumiera_filehandle' which are
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* managed in a 'lumiera_filehandlecache'
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*/
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typedef struct lumiera_file_struct lumiera_file;
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typedef lumiera_file* LumieraFile;
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#include "backend/filehandle.h"
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#include "backend/filedescriptor.h"
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NOBUG_DECLARE_FLAG (lumiera_file);
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#define LUMIERA_FILE_READONLY (O_RDONLY | O_LARGEFILE | O_NOATIME)
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#define LUMIERA_FILE_READWRITE (O_RDWR | O_LARGEFILE | O_NOATIME)
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#define LUMIERA_FILE_CREATE (O_RDWR | O_LARGEFILE | O_NOATIME | O_CREAT | O_EXCL)
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#define LUMIERA_FILE_RECREATE (O_RDWR | O_LARGEFILE | O_NOATIME | O_CREAT | O_TRUNC)
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struct lumiera_file_struct
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{
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const char* name;
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struct lumiera_reference_struct descriptor;
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};
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/**
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*
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*/
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LumieraFile
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lumiera_file_init (LumieraFile self, const char* name, int flags);
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/**
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*
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*/
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LumieraFile
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lumiera_file_destroy (LumieraFile self);
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/**
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*
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*/
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LumieraFile
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lumiera_file_new (const char* name, int flags);
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/**
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*
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*/
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void
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lumiera_file_delete (LumieraFile self);
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#endif
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199
src/backend/filedescriptor.c
Normal file
199
src/backend/filedescriptor.c
Normal file
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@ -0,0 +1,199 @@
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/*
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filedescriptor.c - file handling
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "lib/mutex.h"
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#include "lib/safeclib.h"
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#include "lib/cuckoo.h"
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#include "backend/filedescriptor.h"
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#include <sys/types.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <unistd.h>
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NOBUG_DEFINE_FLAG (filedescriptor);
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static Cuckoo registry = NULL;
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static lumiera_mutex registry_mutex = {PTHREAD_MUTEX_INITIALIZER};
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static size_t
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h1 (const void* item, const uint32_t r)
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{
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const LumieraFiledescriptor i = (const LumieraFiledescriptor) item;
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return i->stat.st_dev^i->stat.st_ino^i->flags^((i->stat.st_dev^i->stat.st_ino^i->flags)>>7)^r;
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}
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static size_t
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h2 (const void* item, const uint32_t r)
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{
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const LumieraFiledescriptor i = (const LumieraFiledescriptor) item;
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return i->stat.st_dev^i->stat.st_ino^i->flags^((i->stat.st_dev^i->stat.st_ino^i->flags)>>5)^r;
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}
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static size_t
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h3 (const void* item, const uint32_t r)
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{
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const LumieraFiledescriptor i = (const LumieraFiledescriptor) item;
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return i->stat.st_dev^i->stat.st_ino^i->flags^((i->stat.st_dev^i->stat.st_ino^i->flags)>>3)^r;
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}
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static int
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cmp (const void* keya, const void* keyb)
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{
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const LumieraFiledescriptor a = (const LumieraFiledescriptor) keya;
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const LumieraFiledescriptor b = (const LumieraFiledescriptor) keyb;
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return a->stat.st_dev == b->stat.st_dev && a->stat.st_ino == b->stat.st_ino && a->flags == b->flags;
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}
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static Cuckoo
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lumiera_filedescriptor_registry_new (void)
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{
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NOBUG_INIT_FLAG (filedescriptor);
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Cuckoo registry = cuckoo_new (h1, h2, h3, cmp,
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sizeof (struct lumiera_reference_struct),
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3);
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if (!registry)
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LUMIERA_DIE (NO_MEMORY);
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return registry;
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}
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/**
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* Find existing filedescriptor or create one
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* @param descriptor strong reference to be initialized with the filedescriptor,
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* a filedescriptor will be deleted when its last string reference gets deleted.
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* @param name name of the file
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* @param flags opening flags for the filedescriptor
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* @return descriptor on success or NULL on error
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*/
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LumieraReference
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lumiera_filedescriptor_acquire (LumieraReference descriptor, const char* name, int flags)
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{
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UNCHECKED;
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lumiera_mutexacquirer registry_lock;
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lumiera_mutexacquirer_init_mutex (®istry_lock, ®istry_mutex, LUMIERA_LOCKED);
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if (!registry)
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registry = lumiera_filedescriptor_registry_new ();
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struct lumiera_filedescriptor_struct findme;
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findme.flags = flags;
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for (int retry = 0; !retry; ++retry)
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{
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if (stat (name, &findme.stat) == 0)
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break;
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else
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{
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if (errno == ENOENT && flags&O_CREAT)
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{
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TRACE (filedescriptor, "try creating file: %s", name);
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char* slash = lumiera_tmpbuf_strndup (name, PATH_MAX);
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while ((slash = strchr (slash+1, '/')))
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{
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*slash = '\0';
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if (mkdir (name, 0777) == -1)
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{
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LUMIERA_ERROR_SET (filedescriptor, ERRNO);
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goto efile;
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}
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*slash = '/';
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}
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int fd;
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fd = creat (name, 0777);
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if (fd == -1)
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{
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LUMIERA_ERROR_SET (filedescriptor, ERRNO);
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goto efile;
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}
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close (fd);
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/* will now retry the fstat once */
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}
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else
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{
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LUMIERA_ERROR_SET (filedescriptor, ERRNO);
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goto efile;
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}
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}
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}
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/* lookup/create descriptor */
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LumieraReference elem = cuckoo_find (registry, &findme);
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if (!elem)
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{
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TRACE (filedescriptor, "Descriptor not found");
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lumiera_reference_strong_init_once (descriptor,
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lumiera_filedescriptor_new (&findme),
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(void(*)(void*))lumiera_filedescriptor_delete);
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if (!lumiera_reference_get (descriptor))
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goto ecreate;
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lumiera_reference weak_descriptor;
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lumiera_reference_weak_init (&weak_descriptor, descriptor);
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cuckoo_insert (registry, &weak_descriptor);
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}
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else
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{
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lumiera_reference_strong_init (descriptor, elem);
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}
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lumiera_mutexacquirer_unlock (®istry_lock);
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return descriptor;
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efile:
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ecreate:
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lumiera_mutexacquirer_unlock (®istry_lock);
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return NULL;
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}
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/**
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* Allocate a new filedescriptor cloned from a template
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* @param template the source filedescriptor
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* @return the constrccted filedescriptor
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*/
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LumieraFiledescriptor
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lumiera_filedescriptor_new (LumieraFiledescriptor template)
|
||||
{
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||||
UNIMPLEMENTED("");
|
||||
return NULL;
|
||||
}
|
||||
|
||||
/**
|
||||
* delete a filedescriptor and free its resources
|
||||
* @param descriptor filedescriptor to be freed
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*/
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void
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lumiera_filedescriptor_delete (LumieraFiledescriptor descriptor)
|
||||
{
|
||||
UNIMPLEMENTED("");
|
||||
}
|
||||
58
src/backend/filedescriptor.h
Normal file
58
src/backend/filedescriptor.h
Normal file
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@ -0,0 +1,58 @@
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/*
|
||||
filedescriptor.h - file handling
|
||||
|
||||
Copyright (C) Lumiera.org
|
||||
2008, Christian Thaeter <ct@pipapo.org>
|
||||
|
||||
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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
|
||||
#ifndef LUMIERA_FILEDESCRIPTOR_H
|
||||
#define LUMIERA_FILEDESCRIPTOR_H
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||||
|
||||
#include "lib/mutex.h"
|
||||
|
||||
#include <sys/stat.h>
|
||||
|
||||
typedef struct lumiera_filedescriptor_struct lumiera_filedescriptor;
|
||||
typedef lumiera_filedescriptor* LumieraFiledescriptor;
|
||||
|
||||
|
||||
#include "backend/filehandle.h"
|
||||
#include "backend/file.h"
|
||||
|
||||
|
||||
struct lumiera_filedescriptor_struct
|
||||
{
|
||||
struct stat stat; /* create after first open, maintained metadata, MUST BE FIRST! */
|
||||
int flags; /* open flags, must be masked for reopen */
|
||||
lumiera_mutex lock; /* locks operations on this file descriptor */
|
||||
unsigned reopened; /* count for reopens 0=not yet opened, 1=first, 2..=reopened*/
|
||||
//LumieraFileMap mappings;
|
||||
//LumieraWriteBuffer writebuffer;
|
||||
};
|
||||
|
||||
|
||||
LumieraReference
|
||||
lumiera_filedescriptor_acquire (LumieraReference descriptor, const char* name, int flags);
|
||||
|
||||
LumieraFiledescriptor
|
||||
lumiera_filedescriptor_new (LumieraFiledescriptor template);
|
||||
|
||||
void
|
||||
lumiera_filedescriptor_delete (LumieraFiledescriptor self);
|
||||
|
||||
|
||||
#endif
|
||||
51
src/backend/filehandle.h
Normal file
51
src/backend/filehandle.h
Normal file
|
|
@ -0,0 +1,51 @@
|
|||
/*
|
||||
filehandle - filehandle management and caching
|
||||
|
||||
Copyright (C) Lumiera.org
|
||||
2008, Christian Thaeter <ct@pipapo.org>
|
||||
|
||||
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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
#ifndef LUMIERA_FILEHANDLE_H
|
||||
#define LUMIERA_FILEHANDLE_H
|
||||
|
||||
#include "lib/error.h"
|
||||
#include "lib/llist.h"
|
||||
|
||||
/**
|
||||
* @file Filehandles
|
||||
*/
|
||||
|
||||
|
||||
/**
|
||||
* File handles
|
||||
*/
|
||||
struct lumiera_filehandle_struct
|
||||
{
|
||||
llist cachenode;
|
||||
int handle;
|
||||
//LumieraFile file;
|
||||
//lumiera_mutex lock;
|
||||
};
|
||||
typedef struct lumiera_filehandle_struct lumiera_filehandle;
|
||||
typedef lumiera_filehandle* LumieraFilehandle;
|
||||
|
||||
LumieraFilehandle
|
||||
lumiera_filehandle_new ();
|
||||
|
||||
void*
|
||||
lumiera_filehandle_destroy_node (LList node);
|
||||
|
||||
#endif
|
||||
83
src/backend/filehandlecache.c
Normal file
83
src/backend/filehandlecache.c
Normal file
|
|
@ -0,0 +1,83 @@
|
|||
/*
|
||||
filehandlecache - filehandle management and caching
|
||||
|
||||
Copyright (C) Lumiera.org
|
||||
2008, Christian Thaeter <ct@pipapo.org>
|
||||
|
||||
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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
|
||||
#include "backend/filehandlecache.h"
|
||||
|
||||
NOBUG_DEFINE_FLAG (lumiera_filehandlecache);
|
||||
|
||||
/* errors */
|
||||
|
||||
LUMIERA_ERROR_DEFINE (FILEHANDLECACHE_NOHANDLE, "No filehandle available");
|
||||
|
||||
|
||||
/**/
|
||||
|
||||
LumieraFilehandlecache
|
||||
lumiera_filehandlecache_init (LumieraFilehandlecache self, int max_entries)
|
||||
{
|
||||
lumiera_mrucache_init (&self->cache, lumiera_filehandle_destroy_node);
|
||||
self->available =max_entries;
|
||||
lumiera_mutex_init (&self->lock);
|
||||
return self;
|
||||
}
|
||||
|
||||
LumieraFilehandlecache
|
||||
lumiera_filehandlecache_destroy (LumieraFilehandlecache self)
|
||||
{
|
||||
self->available += self->cache.cached;
|
||||
lumiera_mrucache_destroy (&self->cache);
|
||||
lumiera_mutex_destroy (&self->lock);
|
||||
return self;
|
||||
}
|
||||
|
||||
|
||||
LumieraFilehandle
|
||||
lumiera_filehandlecache_filehandle_acquire (LumieraFilehandlecache self)
|
||||
{
|
||||
LumieraFilehandle ret;
|
||||
LUMIERA_MUTEX_SECTION (&self->lock)
|
||||
{
|
||||
if (self->available <= 0 && self->cache.cached)
|
||||
{
|
||||
/* pop a filehandle from cache */
|
||||
ret = lumiera_mrucache_pop (&self->cache);
|
||||
if (self->available < 0)
|
||||
/* try to free overallocated filehandles */
|
||||
self->available -= self->available + lumiera_mrucache_age (&self->cache, -self->available);
|
||||
}
|
||||
else
|
||||
{
|
||||
/* allocate new filehandle if we are below the limit or no cached handles where available (overallocating) */
|
||||
ret = lumiera_filehandle_new ();
|
||||
if (!ret)
|
||||
LUMIERA_ERROR_SET (lumiera_filehandlecache, FILEHANDLECACHE_NOHANDLE);
|
||||
else
|
||||
--self->available;
|
||||
}
|
||||
}
|
||||
return ret;
|
||||
}
|
||||
|
||||
void
|
||||
lumiera_filehandlecache_add (LumieraFilehandlecache self, LumieraFilehandle handle)
|
||||
{
|
||||
UNIMPLEMENTED ("");
|
||||
}
|
||||
97
src/backend/filehandlecache.h
Normal file
97
src/backend/filehandlecache.h
Normal file
|
|
@ -0,0 +1,97 @@
|
|||
/*
|
||||
filehandlecache - filehandle management and caching
|
||||
|
||||
Copyright (C) Lumiera.org
|
||||
2008, Christian Thaeter <ct@pipapo.org>
|
||||
|
||||
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., 675 Mass Ave, Cambridge, MA 02139, USA.
|
||||
*/
|
||||
#ifndef LUMIERA_FILEHANDLECACHE_H
|
||||
#define LUMIERA_FILEHANDLECACHE_H
|
||||
|
||||
#include "lib/error.h"
|
||||
#include "lib/mrucache.h"
|
||||
#include "lib/mutex.h"
|
||||
|
||||
#include "backend/filehandle.h"
|
||||
|
||||
/**
|
||||
* @file Filehandle management and caching
|
||||
* The number of filehandles a program can held open is usually limited, since we want to support
|
||||
* using a less limited number of files and closing/opening for each operation is expensive, we
|
||||
* provide a cache to keep the most frequent used files open and gracefully close/recycle unused filehandles.
|
||||
*/
|
||||
|
||||
|
||||
|
||||
/*
|
||||
File handle cache manages file handles
|
||||
*/
|
||||
struct lumiera_filehandlecache_struct
|
||||
{
|
||||
lumiera_mrucache cache;
|
||||
int available;
|
||||
lumiera_mutex lock;
|
||||
};
|
||||
typedef struct lumiera_filehandlecache_struct lumiera_filehandlecache;
|
||||
typedef lumiera_filehandlecache* LumieraFilehandlecache;
|
||||
|
||||
|
||||
/**
|
||||
* Initializes a filehandle cache.
|
||||
* @param self pointer to the cache to be initialized
|
||||
* @param max_entries number how much filehandles shall be managed
|
||||
* @return self as given
|
||||
* The number of elements the cache can hold is static and should be
|
||||
* determined by sysconf (_SC_OPEN_MAX) minus some safety margin.
|
||||
*/
|
||||
LumieraFilehandlecache
|
||||
lumiera_filehandlecache_init (LumieraFilehandlecache self, int max_entries);
|
||||
|
||||
/**
|
||||
* Destroy a filehandle cache.
|
||||
* @param self the cache to be destroyed
|
||||
* @return self as given to the now uninitialized! cache
|
||||
* No filehandles in the cache must be locked, this would be a fatal error.
|
||||
* The handles are closed automatically.
|
||||
*/
|
||||
LumieraFilehandlecache
|
||||
lumiera_filehandlecache_destroy (LumieraFilehandlecache self);
|
||||
|
||||
/**
|
||||
* Get a fresh filehandle.
|
||||
* @param self pointer to the cache
|
||||
* @return the new filehandle
|
||||
* one must call lumiera_mutexacquirer_unlock (&lock) to free the lock on the handle when done
|
||||
*/
|
||||
LumieraFilehandle
|
||||
lumiera_filehandlecache_filehandle_acquire (LumieraFilehandlecache self);
|
||||
|
||||
/**
|
||||
* Add filehande back to cache.
|
||||
* @param self pointer to the cache
|
||||
* @param handle filehandle to be put back
|
||||
*/
|
||||
void
|
||||
lumiera_filehandlecache_add (LumieraFilehandlecache self, LumieraFilehandle handle);
|
||||
|
||||
/**
|
||||
*
|
||||
*/
|
||||
LumieraFilehandle
|
||||
lumiera_filehandlecache_remove (LumieraFilehandlecache self, int fd);
|
||||
|
||||
|
||||
#endif
|
||||
Loading…
Reference in a new issue