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 gboolean scan_missing_running = FALSE; /* must be accessed under @missing_lock */
38
39
40 static gboolean
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
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
66 if (!scan_missing_running)
67 {
68 GSource *source;
69 scan_missing_running = TRUE;
70 source = g_timeout_source_new_seconds (SCAN_MISSING_TIME);
71 g_source_set_callback (source, _km_scan_missing_cb, NULL, NULL);
72 g_source_attach (source, GLIB_PRIVATE_CALL (g_get_worker_context) ());
73 g_source_unref (source);
74 }
75
76 G_UNLOCK (missing_lock);
77 }
78
79 /**
80 * _kh_file_appeared_cb:
81 * @sub: a #kqueue_sub
82 *
83 * A callback function for kqueue-missing subsystem.
84 *
85 * Signals that a missing file has finally appeared in the filesystem.
86 * Emits %G_FILE_MONITOR_EVENT_CREATED.
87 **/
88 static void
89 _kh_file_appeared_cb (kqueue_sub *sub)
90 {
91 gint64 now = g_get_monotonic_time ();
92
93 g_assert (sub != NULL);
94 g_assert (sub->filename);
95
96 if (!g_file_test (sub->filename, G_FILE_TEST_EXISTS))
97 return;
98
99 g_file_monitor_source_handle_event (sub->source, G_FILE_MONITOR_EVENT_CREATED,
100 sub->basename, NULL, NULL, now);
101 g_file_monitor_source_handle_event (sub->source, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT,
102 sub->basename, NULL, NULL, now);
103 }
104
105 /**
106 * _km_scan_missing:
107 * @user_data: unused
108 *
109 * The core missing files watching routine.
110 *
111 * Traverses through a list of missing files, tries to start watching each with
112 * kqueue, removes the appropriate entry and invokes a user callback if the file
113 * has appeared.
114 *
115 * Returns: %FALSE if no missing files left, %TRUE otherwise.
116 **/
117 gboolean
118 _km_scan_missing (kqueue_sub *check_this_sub_only)
119 {
120 GSList *head;
121 GSList *not_missing = NULL;
122 gboolean retval = FALSE;
123
124 G_LOCK (missing_lock);
125
126 if (missing_subs_list)
127 KM_W ("we have a job");
128
129 for (head = missing_subs_list; head; head = head->next)
130 {
131 kqueue_sub *sub = (kqueue_sub *) head->data;
132 g_assert (sub != NULL);
133 g_assert (sub->filename != NULL);
134
135 if (check_this_sub_only != NULL && sub != check_this_sub_only)
136 continue;
137
138 if (_kqsub_start_watching (sub))
139 {
140 KM_W ("file %s now exists, starting watching", sub->filename);
141 if (check_this_sub_only == NULL)
142 _kh_file_appeared_cb (sub);
143 not_missing = g_slist_prepend (not_missing, head);
144 }
145 }
146
147 for (head = not_missing; head; head = head->next)
148 {
149 GSList *link = (GSList *) head->data;
150 missing_subs_list = g_slist_remove_link (missing_subs_list, link);
151 }
152 g_slist_free (not_missing);
153
154 if (missing_subs_list == NULL)
155 {
156 scan_missing_running = FALSE;
157 retval = FALSE;
158 }
159 else
160 retval = TRUE;
161
162 G_UNLOCK (missing_lock);
163 return retval;
164 }
165
166
167 /**
168 * _km_remove:
169 * @sub: a #kqueue_sub
170 *
171 * Removes a subscription from a list of missing files.
172 **/
173 void
174 _km_remove (kqueue_sub *sub)
175 {
176 G_LOCK (missing_lock);
177 missing_subs_list = g_slist_remove (missing_subs_list, sub);
178 G_UNLOCK (missing_lock);
179 }