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glib/gio/gfilemonitor.c

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/* GIO - GLib Input, Output and Streaming Library
*
* Copyright (C) 2006-2007 Red Hat, Inc.
*
* 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 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, write to the
* Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307, USA.
*
* Author: Alexander Larsson <alexl@redhat.com>
*/
#include "config.h"
#include <string.h>
#include "gfilemonitor.h"
#include "gio-marshal.h"
#include "gioenumtypes.h"
#include "gfile.h"
#include "gvfs.h"
#include "glibintl.h"
struct _FileChange;
typedef struct _FileChange FileChange;
static void file_change_free (FileChange *change);
/**
* SECTION:gfilemonitor
* @short_description: File Monitor
* @include: gio/gio.h
*
* Monitors a file or directory for changes.
*
* To obtain a #GFileMonitor for a file or directory, use
* g_file_monitor(), g_file_monitor_file(), or
* g_file_monitor_directory().
*
* To get informed about changes to the file or directory you are
* monitoring, connect to the #GFileMonitor::changed signal. The
* signal will be emitted in the <link
* linkend="g-main-context-push-thread-default">thread-default main
* context</link> of the thread that the monitor was created in
* (though if the global default main context is blocked, this may
* cause notifications to be blocked even if the thread-default
* context is still running).
**/
G_LOCK_DEFINE_STATIC(cancelled);
enum {
CHANGED,
LAST_SIGNAL
};
/* work around a limitation of the aliasing foo */
#undef g_file_monitor
G_DEFINE_ABSTRACT_TYPE (GFileMonitor, g_file_monitor, G_TYPE_OBJECT);
typedef struct {
GFile *file;
guint32 last_sent_change_time; /* 0 == not sent */
guint32 send_delayed_change_at; /* 0 == never */
guint32 send_virtual_changes_done_at; /* 0 == never */
} RateLimiter;
struct _GFileMonitorPrivate {
gboolean cancelled;
int rate_limit_msec;
/* Rate limiting change events */
GHashTable *rate_limiter;
GSource *pending_file_change_source;
GSList *pending_file_changes; /* FileChange */
GSource *timeout;
guint32 timeout_fires_at;
GMainContext *context;
};
enum {
PROP_0,
PROP_RATE_LIMIT,
PROP_CANCELLED
};
static void
g_file_monitor_set_property (GObject *object,
guint prop_id,
const GValue *value,
GParamSpec *pspec)
{
GFileMonitor *monitor;
monitor = G_FILE_MONITOR (object);
switch (prop_id)
{
case PROP_RATE_LIMIT:
g_file_monitor_set_rate_limit (monitor, g_value_get_int (value));
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
static void
g_file_monitor_get_property (GObject *object,
guint prop_id,
GValue *value,
GParamSpec *pspec)
{
GFileMonitor *monitor;
GFileMonitorPrivate *priv;
monitor = G_FILE_MONITOR (object);
priv = monitor->priv;
switch (prop_id)
{
case PROP_RATE_LIMIT:
g_value_set_int (value, priv->rate_limit_msec);
break;
case PROP_CANCELLED:
G_LOCK (cancelled);
g_value_set_boolean (value, priv->cancelled);
G_UNLOCK (cancelled);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
break;
}
}
#define DEFAULT_RATE_LIMIT_MSECS 800
#define DEFAULT_VIRTUAL_CHANGES_DONE_DELAY_SECS 2
static guint signals[LAST_SIGNAL] = { 0 };
static void
rate_limiter_free (RateLimiter *limiter)
{
g_object_unref (limiter->file);
g_slice_free (RateLimiter, limiter);
}
static void
g_file_monitor_finalize (GObject *object)
{
GFileMonitor *monitor;
monitor = G_FILE_MONITOR (object);
if (monitor->priv->timeout)
{
g_source_destroy (monitor->priv->timeout);
g_source_unref (monitor->priv->timeout);
}
g_hash_table_destroy (monitor->priv->rate_limiter);
if (monitor->priv->context)
g_main_context_unref (monitor->priv->context);
G_OBJECT_CLASS (g_file_monitor_parent_class)->finalize (object);
}
static void
g_file_monitor_dispose (GObject *object)
{
GFileMonitor *monitor;
GFileMonitorPrivate *priv;
monitor = G_FILE_MONITOR (object);
priv = monitor->priv;
if (priv->pending_file_change_source)
{
g_source_destroy (priv->pending_file_change_source);
g_source_unref (priv->pending_file_change_source);
priv->pending_file_change_source = NULL;
}
g_slist_foreach (priv->pending_file_changes, (GFunc) file_change_free, NULL);
g_slist_free (priv->pending_file_changes);
priv->pending_file_changes = NULL;
/* Make sure we cancel on last unref */
g_file_monitor_cancel (monitor);
G_OBJECT_CLASS (g_file_monitor_parent_class)->dispose (object);
}
static void
g_file_monitor_class_init (GFileMonitorClass *klass)
{
GObjectClass *object_class;
g_type_class_add_private (klass, sizeof (GFileMonitorPrivate));
object_class = G_OBJECT_CLASS (klass);
object_class->finalize = g_file_monitor_finalize;
object_class->dispose = g_file_monitor_dispose;
object_class->get_property = g_file_monitor_get_property;
object_class->set_property = g_file_monitor_set_property;
/**
* GFileMonitor::changed:
* @monitor: a #GFileMonitor.
* @file: a #GFile.
* @other_file: a #GFile or #NULL.
* @event_type: a #GFileMonitorEvent.
*
* Emitted when @file has been changed.
*
* If using #G_FILE_MONITOR_SEND_MOVED flag and @event_type is
* #G_FILE_MONITOR_SEND_MOVED, @file will be set to a #GFile containing the
* old path, and @other_file will be set to a #GFile containing the new path.
*
* In all the other cases, @other_file will be set to #NULL.
**/
signals[CHANGED] =
g_signal_new (I_("changed"),
G_TYPE_FILE_MONITOR,
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GFileMonitorClass, changed),
NULL, NULL,
_gio_marshal_VOID__OBJECT_OBJECT_ENUM,
G_TYPE_NONE, 3,
G_TYPE_FILE, G_TYPE_FILE, G_TYPE_FILE_MONITOR_EVENT);
g_object_class_install_property (object_class,
PROP_RATE_LIMIT,
g_param_spec_int ("rate-limit",
P_("Rate limit"),
P_("The limit of the monitor to watch for changes, in milliseconds"),
0, G_MAXINT,
DEFAULT_RATE_LIMIT_MSECS,
G_PARAM_READWRITE|
G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
g_object_class_install_property (object_class,
PROP_CANCELLED,
g_param_spec_boolean ("cancelled",
P_("Cancelled"),
P_("Whether the monitor has been cancelled"),
FALSE,
G_PARAM_READABLE|
G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
}
static void
g_file_monitor_init (GFileMonitor *monitor)
{
monitor->priv = G_TYPE_INSTANCE_GET_PRIVATE (monitor,
G_TYPE_FILE_MONITOR,
GFileMonitorPrivate);
monitor->priv->rate_limit_msec = DEFAULT_RATE_LIMIT_MSECS;
monitor->priv->rate_limiter = g_hash_table_new_full (g_file_hash, (GEqualFunc)g_file_equal,
NULL, (GDestroyNotify) rate_limiter_free);
monitor->priv->context = g_main_context_get_thread_default ();
}
/**
* g_file_monitor_is_cancelled:
* @monitor: a #GFileMonitor
*
* Returns whether the monitor is canceled.
*
* Returns: %TRUE if monitor is canceled. %FALSE otherwise.
**/
gboolean
g_file_monitor_is_cancelled (GFileMonitor *monitor)
{
gboolean res;
g_return_val_if_fail (G_IS_FILE_MONITOR (monitor), FALSE);
G_LOCK (cancelled);
res = monitor->priv->cancelled;
G_UNLOCK (cancelled);
return res;
}
/**
* g_file_monitor_cancel:
* @monitor: a #GFileMonitor.
*
* Cancels a file monitor.
*
* Returns: %TRUE if monitor was cancelled.
**/
gboolean
g_file_monitor_cancel (GFileMonitor* monitor)
{
GFileMonitorClass *klass;
g_return_val_if_fail (G_IS_FILE_MONITOR (monitor), FALSE);
G_LOCK (cancelled);
if (monitor->priv->cancelled)
{
G_UNLOCK (cancelled);
return TRUE;
}
monitor->priv->cancelled = TRUE;
G_UNLOCK (cancelled);
g_object_notify (G_OBJECT (monitor), "cancelled");
klass = G_FILE_MONITOR_GET_CLASS (monitor);
return (* klass->cancel) (monitor);
}
/**
* g_file_monitor_set_rate_limit:
* @monitor: a #GFileMonitor.
* @limit_msecs: a non-negative integer with the limit in milliseconds
* to poll for changes
*
* Sets the rate limit to which the @monitor will report
* consecutive change events to the same file.
*/
void
g_file_monitor_set_rate_limit (GFileMonitor *monitor,
gint limit_msecs)
{
GFileMonitorPrivate *priv;
g_return_if_fail (G_IS_FILE_MONITOR (monitor));
g_return_if_fail (limit_msecs >= 0);
priv = monitor->priv;
if (priv->rate_limit_msec != limit_msecs)
{
monitor->priv->rate_limit_msec = limit_msecs;
g_object_notify (G_OBJECT (monitor), "rate-limit");
}
}
struct _FileChange {
GFile *child;
GFile *other_file;
GFileMonitorEvent event_type;
};
static void
file_change_free (FileChange *change)
{
g_object_unref (change->child);
if (change->other_file)
g_object_unref (change->other_file);
g_slice_free (FileChange, change);
}
static gboolean
emit_cb (gpointer data)
{
GFileMonitor *monitor = G_FILE_MONITOR (data);
GSList *pending, *iter;
pending = g_slist_reverse (monitor->priv->pending_file_changes);
monitor->priv->pending_file_changes = NULL;
if (monitor->priv->pending_file_change_source)
{
g_source_unref (monitor->priv->pending_file_change_source);
monitor->priv->pending_file_change_source = NULL;
}
g_object_ref (monitor);
for (iter = pending; iter; iter = iter->next)
{
FileChange *change = iter->data;
g_signal_emit (monitor, signals[CHANGED], 0,
change->child, change->other_file, change->event_type);
file_change_free (change);
}
g_slist_free (pending);
g_object_unref (monitor);
return FALSE;
}
static void
emit_in_idle (GFileMonitor *monitor,
GFile *child,
GFile *other_file,
GFileMonitorEvent event_type)
{
GSource *source;
FileChange *change;
GFileMonitorPrivate *priv;
priv = monitor->priv;
change = g_slice_new (FileChange);
change->child = g_object_ref (child);
if (other_file)
change->other_file = g_object_ref (other_file);
else
change->other_file = NULL;
change->event_type = event_type;
if (!priv->pending_file_change_source)
{
source = g_idle_source_new ();
priv->pending_file_change_source = source;
g_source_set_priority (source, 0);
/* We don't ref monitor here - instead dispose will free any
* pending idles.
*/
g_source_set_callback (source, emit_cb, monitor, NULL);
g_source_attach (source, monitor->priv->context);
}
/* We reverse this in the processor */
priv->pending_file_changes = g_slist_prepend (priv->pending_file_changes, change);
}
static guint32
get_time_msecs (void)
{
return g_thread_gettime() / (1000 * 1000);
}
static guint32
time_difference (guint32 from, guint32 to)
{
if (from > to)
return 0;
return to - from;
}
/* Change event rate limiting support: */
static RateLimiter *
new_limiter (GFileMonitor *monitor,
GFile *file)
{
RateLimiter *limiter;
limiter = g_slice_new0 (RateLimiter);
limiter->file = g_object_ref (file);
g_hash_table_insert (monitor->priv->rate_limiter, file, limiter);
return limiter;
}
static void
rate_limiter_send_virtual_changes_done_now (GFileMonitor *monitor,
RateLimiter *limiter)
{
if (limiter->send_virtual_changes_done_at != 0)
{
emit_in_idle (monitor, limiter->file, NULL,
G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
limiter->send_virtual_changes_done_at = 0;
}
}
static void
rate_limiter_send_delayed_change_now (GFileMonitor *monitor,
RateLimiter *limiter,
guint32 time_now)
{
if (limiter->send_delayed_change_at != 0)
{
emit_in_idle (monitor,
limiter->file, NULL,
G_FILE_MONITOR_EVENT_CHANGED);
limiter->send_delayed_change_at = 0;
limiter->last_sent_change_time = time_now;
}
}
typedef struct {
guint32 min_time;
guint32 time_now;
GFileMonitor *monitor;
} ForEachData;
static gboolean
calc_min_time (GFileMonitor *monitor,
RateLimiter *limiter,
guint32 time_now,
guint32 *min_time)
{
gboolean delete_me;
guint32 expire_at;
delete_me = TRUE;
if (limiter->last_sent_change_time != 0)
{
/* Set a timeout at 2*rate limit so that we can clear out the change from the hash eventualy */
expire_at = limiter->last_sent_change_time + 2 * monitor->priv->rate_limit_msec;
if (time_difference (time_now, expire_at) > 0)
{
delete_me = FALSE;
*min_time = MIN (*min_time,
time_difference (time_now, expire_at));
}
}
if (limiter->send_delayed_change_at != 0)
{
delete_me = FALSE;
*min_time = MIN (*min_time,
time_difference (time_now, limiter->send_delayed_change_at));
}
if (limiter->send_virtual_changes_done_at != 0)
{
delete_me = FALSE;
*min_time = MIN (*min_time,
time_difference (time_now, limiter->send_virtual_changes_done_at));
}
return delete_me;
}
static gboolean
foreach_rate_limiter_fire (gpointer key,
gpointer value,
gpointer user_data)
{
RateLimiter *limiter = value;
ForEachData *data = user_data;
if (limiter->send_delayed_change_at != 0 &&
time_difference (data->time_now, limiter->send_delayed_change_at) == 0)
rate_limiter_send_delayed_change_now (data->monitor, limiter, data->time_now);
if (limiter->send_virtual_changes_done_at != 0 &&
time_difference (data->time_now, limiter->send_virtual_changes_done_at) == 0)
rate_limiter_send_virtual_changes_done_now (data->monitor, limiter);
return calc_min_time (data->monitor, limiter, data->time_now, &data->min_time);
}
static gboolean
rate_limiter_timeout (gpointer timeout_data)
{
GFileMonitor *monitor = timeout_data;
ForEachData data;
GSource *source;
data.min_time = G_MAXUINT32;
data.monitor = monitor;
data.time_now = get_time_msecs ();
g_hash_table_foreach_remove (monitor->priv->rate_limiter,
foreach_rate_limiter_fire,
&data);
/* Remove old timeout */
if (monitor->priv->timeout)
{
g_source_destroy (monitor->priv->timeout);
g_source_unref (monitor->priv->timeout);
monitor->priv->timeout = NULL;
monitor->priv->timeout_fires_at = 0;
}
/* Set up new timeout */
if (data.min_time != G_MAXUINT32)
{
source = g_timeout_source_new (data.min_time + 1); /* + 1 to make sure we've really passed the time */
g_source_set_callback (source, rate_limiter_timeout, monitor, NULL);
g_source_attach (source, monitor->priv->context);
monitor->priv->timeout = source;
monitor->priv->timeout_fires_at = data.time_now + data.min_time;
}
return FALSE;
}
static gboolean
foreach_rate_limiter_update (gpointer key,
gpointer value,
gpointer user_data)
{
RateLimiter *limiter = value;
ForEachData *data = user_data;
return calc_min_time (data->monitor, limiter, data->time_now, &data->min_time);
}
static void
update_rate_limiter_timeout (GFileMonitor *monitor,
guint new_time)
{
ForEachData data;
GSource *source;
if (monitor->priv->timeout_fires_at != 0 && new_time != 0 &&
time_difference (new_time, monitor->priv->timeout_fires_at) == 0)
return; /* Nothing to do, we already fire earlier than that */
data.min_time = G_MAXUINT32;
data.monitor = monitor;
data.time_now = get_time_msecs ();
g_hash_table_foreach_remove (monitor->priv->rate_limiter,
foreach_rate_limiter_update,
&data);
/* Remove old timeout */
if (monitor->priv->timeout)
{
g_source_destroy (monitor->priv->timeout);
g_source_unref (monitor->priv->timeout);
monitor->priv->timeout_fires_at = 0;
monitor->priv->timeout = NULL;
}
/* Set up new timeout */
if (data.min_time != G_MAXUINT32)
{
source = g_timeout_source_new (data.min_time + 1); /* + 1 to make sure we've really passed the time */
g_source_set_callback (source, rate_limiter_timeout, monitor, NULL);
g_source_attach (source, monitor->priv->context);
monitor->priv->timeout = source;
monitor->priv->timeout_fires_at = data.time_now + data.min_time;
}
}
/**
* g_file_monitor_emit_event:
* @monitor: a #GFileMonitor.
* @child: a #GFile.
* @other_file: a #GFile.
* @event_type: a set of #GFileMonitorEvent flags.
*
* Emits the #GFileMonitor::changed signal if a change
* has taken place. Should be called from file monitor
* implementations only.
*
* The signal will be emitted from an idle handler (in the <link
* linkend="g-main-context-push-thread-default">thread-default main
* context</link>).
**/
void
g_file_monitor_emit_event (GFileMonitor *monitor,
GFile *child,
GFile *other_file,
GFileMonitorEvent event_type)
{
guint32 time_now, since_last;
gboolean emit_now;
RateLimiter *limiter;
g_return_if_fail (G_IS_FILE_MONITOR (monitor));
g_return_if_fail (G_IS_FILE (child));
limiter = g_hash_table_lookup (monitor->priv->rate_limiter, child);
if (event_type != G_FILE_MONITOR_EVENT_CHANGED)
{
if (limiter)
{
rate_limiter_send_delayed_change_now (monitor, limiter, get_time_msecs ());
if (event_type == G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT)
limiter->send_virtual_changes_done_at = 0;
else
rate_limiter_send_virtual_changes_done_now (monitor, limiter);
update_rate_limiter_timeout (monitor, 0);
}
emit_in_idle (monitor, child, other_file, event_type);
}
else
{
/* Changed event, rate limit */
time_now = get_time_msecs ();
emit_now = TRUE;
if (limiter)
{
since_last = time_difference (limiter->last_sent_change_time, time_now);
if (since_last < monitor->priv->rate_limit_msec)
{
/* We ignore this change, but arm a timer so that we can fire it later if we
don't get any other events (that kill this timeout) */
emit_now = FALSE;
if (limiter->send_delayed_change_at == 0)
{
limiter->send_delayed_change_at = time_now + monitor->priv->rate_limit_msec;
update_rate_limiter_timeout (monitor, limiter->send_delayed_change_at);
}
}
}
if (limiter == NULL)
limiter = new_limiter (monitor, child);
if (emit_now)
{
emit_in_idle (monitor, child, other_file, event_type);
limiter->last_sent_change_time = time_now;
limiter->send_delayed_change_at = 0;
/* Set a timeout of 2*rate limit so that we can clear out the change from the hash eventualy */
update_rate_limiter_timeout (monitor, time_now + 2 * monitor->priv->rate_limit_msec);
}
/* Schedule a virtual change done. This is removed if we get a real one, and
postponed if we get more change events. */
limiter->send_virtual_changes_done_at = time_now + DEFAULT_VIRTUAL_CHANGES_DONE_DELAY_SECS * 1000;
update_rate_limiter_timeout (monitor, limiter->send_virtual_changes_done_at);
}
}
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