/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 2; tab-width: 8 -*- */

/* inotify-missing.c - GVFS Monitor based on inotify.

   Copyright (C) 2005 John McCutchan

   SPDX-License-Identifier: LGPL-2.1-or-later

   This library 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.

   This library 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 this library; if not, see <http://www.gnu.org/licenses/>.

   Authors: 

     John McCutchan <john@johnmccutchan.com>

*/

#include "config.h"

#include <glib.h>

#include "inotify-missing.h"

#include "inotify-path.h"

#include "glib-private.h"

#define SCAN_MISSING_TIME 4 /* 1/4 Hz */

static gboolean im_debug_enabled = FALSE;

#define IM_W if (im_debug_enabled) g_warning

/* We put inotify_sub's that are missing on this list */

static GList *missing_sub_list = NULL;

static gboolean im_scan_missing (gpointer user_data);

static gboolean scan_missing_running = FALSE;

static void (*missing_cb)(inotify_sub *sub) = NULL;

G_LOCK_EXTERN (inotify_lock);

/* inotify_lock must be held before calling */

void

_im_startup (void (*callback)(inotify_sub *sub))

{

  static gboolean initialized = FALSE;

  if (!initialized)

    {

      missing_cb = callback;

      initialized = TRUE;

    }

}

/* inotify_lock must be held before calling */

void

_im_add (inotify_sub *sub)

{

  if (g_list_find (missing_sub_list, sub))

    {

      IM_W ("asked to add %s to missing list but it's already on the list!\n", sub->dirname);

      return;

    }

  IM_W ("adding %s to missing list\n", sub->dirname);

  missing_sub_list = g_list_prepend (missing_sub_list, sub);

  /* If the timeout is turned off, we turn it back on */

  if (!scan_missing_running)

    {

      GSource *source;

      scan_missing_running = TRUE;

      source = g_timeout_source_new_seconds (SCAN_MISSING_TIME);

      g_source_set_callback (source, im_scan_missing, NULL, NULL);

      g_source_attach (source, GLIB_PRIVATE_CALL (g_get_worker_context) ());

      g_source_unref (source);

    }

}

/* inotify_lock must be held before calling */

void

_im_rm (inotify_sub *sub)

{

  GList *link;

  link = g_list_find (missing_sub_list, sub);

  if (!link)

    {

      IM_W ("asked to remove %s from missing list but it isn't on the list!\n", sub->dirname);

      return;

    }

  IM_W ("removing %s from missing list\n", sub->dirname);

  missing_sub_list = g_list_remove_link (missing_sub_list, link);

  g_list_free_1 (link);

}

/* Scans the list of missing subscriptions checking if they

 * are available yet.

 */

static gboolean

im_scan_missing (gpointer user_data)

{

  GList *nolonger_missing = NULL;

  GList *l;

  G_LOCK (inotify_lock);

  IM_W ("scanning missing list with %d items\n", g_list_length (missing_sub_list));

  for (l = missing_sub_list; l; l = l->next)

    {

      inotify_sub *sub = l->data;

      gboolean not_m = FALSE;

      IM_W ("checking %p\n", sub);

      g_assert (sub);

      g_assert (sub->dirname);

      not_m = _ip_start_watching (sub);

      if (not_m)

  {

    missing_cb (sub);

    IM_W ("removed %s from missing list\n", sub->dirname);

    /* We have to build a list of list nodes to remove from the

     * missing_sub_list. We do the removal outside of this loop.

     */

    nolonger_missing = g_list_prepend (nolonger_missing, l);

  } 

    }

  for (l = nolonger_missing; l ; l = l->next)

    {

      GList *llink = l->data;

      missing_sub_list = g_list_remove_link (missing_sub_list, llink);

      g_list_free_1 (llink);

    }

  g_list_free (nolonger_missing);

  /* If the missing list is now empty, we disable the timeout */

  if (missing_sub_list == NULL)

    {

      scan_missing_running = FALSE;

      G_UNLOCK (inotify_lock);

      return FALSE;

    }

  else

    {

      G_UNLOCK (inotify_lock);

      return TRUE;

    }

}