1 /*******************************************************************************
2 Copyright (c) 2011, 2012 Dmitry Matveev <me@dmitrymatveev.co.uk>
3
4 Permission is hereby granted, free of charge, to any person obtaining a copy
5 of this software and associated documentation files (the "Software"), to deal
6 in the Software without restriction, including without limitation the rights
7 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
8 copies of the Software, and to permit persons to whom the Software is
9 furnished to do so, subject to the following conditions:
10
11 The above copyright notice and this permission notice shall be included in
12 all copies or substantial portions of the Software.
13
14 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
17 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
18 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
19 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
20 THE SOFTWARE.
21 *******************************************************************************/
22
23 #include <glib.h>
24 #include "glib-private.h"
25
26 #include "kqueue-helper.h"
27
28
29 #define SCAN_MISSING_TIME 4 /* 1/4 Hz */
30
31 static gboolean km_debug_enabled = FALSE;
32 #define KM_W if (km_debug_enabled) g_warning
33
34 static GSList *missing_subs_list = NULL;
35 G_LOCK_DEFINE_STATIC (missing_lock);
36
37 static volatile gboolean scan_missing_running = FALSE;
38
39
40 static gboolean
_km_scan_missing_cb(gpointer user_data)41 _km_scan_missing_cb (gpointer user_data)
42 {
43 return _km_scan_missing (NULL);
44 }
45
46 /**
47 * _km_add_missing:
48 * @sub: a #kqueue_sub
49 *
50 * Adds a subscription to the missing files list.
51 **/
52 void
_km_add_missing(kqueue_sub * sub)53 _km_add_missing (kqueue_sub *sub)
54 {
55 G_LOCK (missing_lock);
56 if (g_slist_find (missing_subs_list, sub))
57 {
58 KM_W ("asked to add %s to missing list but it's already on the list!\n", sub->filename);
59 G_UNLOCK (missing_lock);
60 return;
61 }
62
63 KM_W ("adding %s to missing list\n", sub->filename);
64 missing_subs_list = g_slist_prepend (missing_subs_list, sub);
65 G_UNLOCK (missing_lock);
66
67 if (!scan_missing_running)
68 {
69 GSource *source;
70 scan_missing_running = TRUE;
71 source = g_timeout_source_new_seconds (SCAN_MISSING_TIME);
72 g_source_set_callback (source, _km_scan_missing_cb, NULL, NULL);
73 g_source_attach (source, GLIB_PRIVATE_CALL (g_get_worker_context) ());
74 g_source_unref (source);
75 }
76 }
77
78 /**
79 * _kh_file_appeared_cb:
80 * @sub: a #kqueue_sub
81 *
82 * A callback function for kqueue-missing subsystem.
83 *
84 * Signals that a missing file has finally appeared in the filesystem.
85 * Emits %G_FILE_MONITOR_EVENT_CREATED.
86 **/
87 static void
_kh_file_appeared_cb(kqueue_sub * sub)88 _kh_file_appeared_cb (kqueue_sub *sub)
89 {
90 gint64 now = g_get_monotonic_time ();
91
92 g_assert (sub != NULL);
93 g_assert (sub->filename);
94
95 if (!g_file_test (sub->filename, G_FILE_TEST_EXISTS))
96 return;
97
98 g_file_monitor_source_handle_event (sub->source, G_FILE_MONITOR_EVENT_CREATED,
99 sub->basename, NULL, NULL, now);
100 g_file_monitor_source_handle_event (sub->source, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT,
101 sub->basename, NULL, NULL, now);
102 }
103
104 /**
105 * _km_scan_missing:
106 * @user_data: unused
107 *
108 * The core missing files watching routine.
109 *
110 * Traverses through a list of missing files, tries to start watching each with
111 * kqueue, removes the appropriate entry and invokes a user callback if the file
112 * has appeared.
113 *
114 * Returns: %FALSE if no missing files left, %TRUE otherwise.
115 **/
116 gboolean
_km_scan_missing(kqueue_sub * check_this_sub_only)117 _km_scan_missing (kqueue_sub *check_this_sub_only)
118 {
119 GSList *head;
120 GSList *not_missing = NULL;
121 gboolean retval = FALSE;
122
123 G_LOCK (missing_lock);
124
125 if (missing_subs_list)
126 KM_W ("we have a job");
127
128 for (head = missing_subs_list; head; head = head->next)
129 {
130 kqueue_sub *sub = (kqueue_sub *) head->data;
131 g_assert (sub != NULL);
132 g_assert (sub->filename != NULL);
133
134 if (check_this_sub_only != NULL && sub != check_this_sub_only)
135 continue;
136
137 if (_kqsub_start_watching (sub))
138 {
139 KM_W ("file %s now exists, starting watching", sub->filename);
140 if (check_this_sub_only == NULL)
141 _kh_file_appeared_cb (sub);
142 not_missing = g_slist_prepend (not_missing, head);
143 }
144 }
145
146 for (head = not_missing; head; head = head->next)
147 {
148 GSList *link = (GSList *) head->data;
149 missing_subs_list = g_slist_remove_link (missing_subs_list, link);
150 }
151 g_slist_free (not_missing);
152
153 if (missing_subs_list == NULL)
154 {
155 scan_missing_running = FALSE;
156 retval = FALSE;
157 }
158 else
159 retval = TRUE;
160
161 G_UNLOCK (missing_lock);
162 return retval;
163 }
164
165
166 /**
167 * _km_remove:
168 * @sub: a #kqueue_sub
169 *
170 * Removes a subscription from a list of missing files.
171 **/
172 void
_km_remove(kqueue_sub * sub)173 _km_remove (kqueue_sub *sub)
174 {
175 G_LOCK (missing_lock);
176 missing_subs_list = g_slist_remove (missing_subs_list, sub);
177 G_UNLOCK (missing_lock);
178 }
179