From ffccd5b2b05243e7976db80f90f453dccfae9886 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 15 Apr 2024 22:22:03 +0200 Subject: Adding upstream version 3:4.8.30. Signed-off-by: Daniel Baumann --- lib/vfs/gc.c | 335 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 335 insertions(+) create mode 100644 lib/vfs/gc.c (limited to 'lib/vfs/gc.c') diff --git a/lib/vfs/gc.c b/lib/vfs/gc.c new file mode 100644 index 0000000..0914b75 --- /dev/null +++ b/lib/vfs/gc.c @@ -0,0 +1,335 @@ +/* + Virtual File System garbage collection code + + Copyright (C) 2003-2023 + Free Software Foundation, Inc. + + Written by: + Miguel de Icaza, 1995 + Jakub Jelinek, 1995 + Pavel Machek, 1998 + Pavel Roskin, 2003 + + This file is part of the Midnight Commander. + + The Midnight Commander 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 3 of the License, + or (at your option) any later version. + + The Midnight Commander 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, see . + */ + +/** + * \file + * \brief Source: Virtual File System: garbage collection code + * \author Miguel de Icaza + * \author Jakub Jelinek + * \author Pavel Machek + * \author Pavel Roskin + * \date 1995, 1998, 2003 + */ + + +#include + +#include + +#include "lib/global.h" +#include "lib/event.h" +#include "lib/util.h" /* MC_PTR_FREE */ + +#include "vfs.h" +#include "utilvfs.h" + +#include "gc.h" + +/* + * The garbage collection mechanism is based on "stamps". + * + * A stamp is a record that says "I'm a filesystem which is no longer in + * use. Free me when you get a chance." + * + * This file contains a set of functions used for managing this stamp. You + * should use them when you write your own filesystem. Here are some rules + * of thumb: + * + * (1) When the last open file in your filesystem gets closed, conditionally + * create a stamp. You do this with vfs_stamp_create(). (The meaning + * of "conditionally" is explained below.) + * + * (2) When a file in your filesystem is opened, delete the stamp. You do + * this with vfs_rmstamp(). + * + * (3) When a path inside your filesystem is invoked, call vfs_stamp() to + * postpone the free'ing of your filesystem a bit. (This simply updates + * a timestamp variable inside the stamp.) + * + * Additionally, when a user navigates to a new directory in a panel (or a + * programmer uses mc_chdir()), a stamp is conditionally created for the + * previous directory's filesystem. This ensures that that filesystem is + * free'ed. (see: _do_panel_cd() -> vfs_release_path(); mc_chdir()). + * + * We've spoken here of "conditionally creating" a stamp. What we mean is + * that vfs_stamp_create() is to be used: this function creates a stamp + * only if no directories are open (aka "active") in your filesystem. (If + * there _are_ directories open, it means that the filesystem is in use, in + * which case we don't want to free it.) + */ + +/*** global variables ****************************************************************************/ + +int vfs_timeout = 60; /* VFS timeout in seconds */ + +/*** file scope macro definitions ****************************************************************/ + +#define VFS_STAMPING(a) ((struct vfs_stamping *)(a)) + +/*** file scope type declarations ****************************************************************/ + +struct vfs_stamping +{ + struct vfs_class *v; + vfsid id; + gint64 time; +}; + +/*** forward declarations (file scope functions) *************************************************/ + +/*** file scope variables ************************************************************************/ + +static GSList *stamps = NULL; + +/* --------------------------------------------------------------------------------------------- */ +/*** file scope functions ************************************************************************/ +/* --------------------------------------------------------------------------------------------- */ + +static gint +vfs_stamp_compare (gconstpointer a, gconstpointer b) +{ + const struct vfs_stamping *vsa = (const struct vfs_stamping *) a; + const struct vfs_stamping *vsb = (const struct vfs_stamping *) b; + + return (vsa == NULL || vsb == NULL || (vsa->v == vsb->v && vsa->id == vsb->id)) ? 0 : 1; +} + +/* --------------------------------------------------------------------------------------------- */ + +static void +vfs_addstamp (struct vfs_class *v, vfsid id) +{ + if ((v->flags & VFSF_LOCAL) == 0 && id != NULL && !vfs_stamp (v, id)) + { + struct vfs_stamping *stamp; + + stamp = g_new (struct vfs_stamping, 1); + stamp->v = v; + stamp->id = id; + stamp->time = g_get_monotonic_time (); + + stamps = g_slist_append (stamps, stamp); + } +} + +/* --------------------------------------------------------------------------------------------- */ +/*** public functions ****************************************************************************/ +/* --------------------------------------------------------------------------------------------- */ + +gboolean +vfs_stamp (struct vfs_class *v, vfsid id) +{ + struct vfs_stamping what = { + .v = v, + .id = id + }; + GSList *stamp; + gboolean ret = FALSE; + + stamp = g_slist_find_custom (stamps, &what, vfs_stamp_compare); + if (stamp != NULL && stamp->data != NULL) + { + VFS_STAMPING (stamp->data)->time = g_get_monotonic_time (); + ret = TRUE; + } + + return ret; +} + +/* --------------------------------------------------------------------------------------------- */ + +void +vfs_rmstamp (struct vfs_class *v, vfsid id) +{ + struct vfs_stamping what = { + .v = v, + .id = id + }; + GSList *stamp; + + stamp = g_slist_find_custom (stamps, &what, vfs_stamp_compare); + if (stamp != NULL) + { + g_free (stamp->data); + stamps = g_slist_delete_link (stamps, stamp); + } +} + +/* --------------------------------------------------------------------------------------------- */ + +void +vfs_stamp_path (const vfs_path_t * vpath) +{ + vfsid id; + struct vfs_class *me; + + me = VFS_CLASS (vfs_path_get_last_path_vfs (vpath)); + id = vfs_getid (vpath); + vfs_addstamp (me, id); +} + +/* --------------------------------------------------------------------------------------------- */ +/** + * Create a new timestamp item by VFS class and VFS id. + */ + +void +vfs_stamp_create (struct vfs_class *vclass, vfsid id) +{ + vfsid nvfsid; + + ev_vfs_stamp_create_t event_data = { vclass, id, FALSE }; + const vfs_path_t *vpath; + struct vfs_class *me; + + /* There are three directories we have to take care of: current_dir, + current_panel->cwd and other_panel->cwd. Although most of the time either + current_dir and current_panel->cwd or current_dir and other_panel->cwd are the + same, it's possible that all three are different -- Norbert */ + + if (!mc_event_present (MCEVENT_GROUP_CORE, "vfs_timestamp")) + return; + + vpath = vfs_get_raw_current_dir (); + me = VFS_CLASS (vfs_path_get_last_path_vfs (vpath)); + + nvfsid = vfs_getid (vpath); + vfs_rmstamp (me, nvfsid); + + if (!(id == NULL || (me == vclass && nvfsid == id))) + { + mc_event_raise (MCEVENT_GROUP_CORE, "vfs_timestamp", (gpointer) & event_data); + + if (!event_data.ret && vclass != NULL && vclass->nothingisopen != NULL + && vclass->nothingisopen (id)) + vfs_addstamp (vclass, id); + } +} + +/* --------------------------------------------------------------------------------------------- */ +/** This is called from timeout handler with now = FALSE, + or can be called with now = TRUE to force freeing all filesystems */ + +void +vfs_expire (gboolean now) +{ + static gboolean locked = FALSE; + gint64 curr_time, exp_time; + GSList *stamp; + + /* Avoid recursive invocation, e.g. when one of the free functions + calls message */ + if (locked) + return; + locked = TRUE; + + curr_time = g_get_monotonic_time (); + exp_time = curr_time - vfs_timeout * G_USEC_PER_SEC; + + if (now) + { + /* reverse list to free nested VFSes at first */ + stamps = g_slist_reverse (stamps); + } + + /* NULLize stamps that point to expired VFS */ + for (stamp = stamps; stamp != NULL; stamp = g_slist_next (stamp)) + { + struct vfs_stamping *stamping = VFS_STAMPING (stamp->data); + + if (now) + { + /* free VFS forced */ + if (stamping->v->free != NULL) + stamping->v->free (stamping->id); + MC_PTR_FREE (stamp->data); + } + else if (stamping->time <= exp_time) + { + /* update timestamp of VFS that is in use, or free unused VFS */ + if (stamping->v->nothingisopen != NULL && !stamping->v->nothingisopen (stamping->id)) + stamping->time = curr_time; + else + { + if (stamping->v->free != NULL) + stamping->v->free (stamping->id); + MC_PTR_FREE (stamp->data); + } + } + } + + /* then remove NULLized stamps */ + stamps = g_slist_remove_all (stamps, NULL); + + locked = FALSE; +} + +/* --------------------------------------------------------------------------------------------- */ +/* + * Return the number of seconds remaining to the vfs timeout. + * FIXME: The code should be improved to actually return the number of + * seconds until the next item times out. + */ + +int +vfs_timeouts (void) +{ + return stamps != NULL ? 10 : 0; +} + +/* --------------------------------------------------------------------------------------------- */ + +void +vfs_timeout_handler (void) +{ + vfs_expire (FALSE); +} + +/* --------------------------------------------------------------------------------------------- */ + +void +vfs_release_path (const vfs_path_t * vpath) +{ + vfsid id; + struct vfs_class *me; + + me = VFS_CLASS (vfs_path_get_last_path_vfs (vpath)); + id = vfs_getid (vpath); + vfs_stamp_create (me, id); +} + +/* --------------------------------------------------------------------------------------------- */ +/* Free all data */ + +void +vfs_gc_done (void) +{ + vfs_expire (TRUE); +} + +/* --------------------------------------------------------------------------------------------- */ -- cgit v1.2.3