2 * UCW Library -- Logging: Management of Log Streams
4 * (c) 2008 Tomas Gavenciak <gavento@ucw.cz>
5 * (c) 2009 Martin Mares <mj@ucw.cz>
7 * This software may be freely distributed and used according to the terms
8 * of the GNU Lesser General Public License.
13 #include "ucw/simple-lists.h"
17 /* Initial number of streams to allocate (must be >=2) */
18 #define LS_INIT_STREAMS 8
20 /* Flag indicating initialization of the module */
21 static int log_initialized = 0;
23 /* The head of the list of freed log_streams indexes in log_streams.ptr (~0U if none free).
24 * Freed positions in log_streams.ptr are connected into a linked list in the following way:
25 * log_streams.ptr[log_streams_free].levels is the index of next freed position (or ~0U) */
26 static uns log_streams_free = ~0U;
28 /* Initialize the logstream module.
29 * It is not neccessary to call this explicitely as it is called by
30 * the first log_new_stream() (for backward compatibility and ease of use). */
37 /* Create the growing array */
38 lsbuf_init(&log_streams);
39 lsbuf_set_size(&log_streams, LS_INIT_STREAMS);
41 bzero(log_streams.ptr, sizeof(struct log_stream*) * (log_streams.len));
42 log_streams_free = ~0U;
46 /* init the default stream (0) as forwarder to fd2 */
47 struct log_stream *ls = log_new_stream(sizeof(*ls));
48 ASSERT(ls == log_streams.ptr[0]);
49 ASSERT(ls->regnum == 0);
51 log_add_substream(ls, &log_stream_default);
54 /* Close all open streams, un-initialize the module, free all memory,
55 * and fall back to using only log_stream_default. */
62 for (int i=0; i < log_streams_after; i++)
64 if (log_streams.ptr[i]->regnum >= 0)
65 log_close_stream(log_streams.ptr[i]);
66 xfree(log_streams.ptr[i]);
69 /* Back to the default state */
70 lsbuf_done(&log_streams);
71 log_streams_after = 0;
72 log_streams_free = ~0U;
76 /* Add a new substream. The parent stream takes a reference on the substream,
77 * preventing it from being closed as long as it is linked. */
79 log_add_substream(struct log_stream *where, struct log_stream *what)
84 simp_node *n = xmalloc(sizeof(simp_node));
85 n->p = log_ref_stream(what);
86 clist_add_tail(&where->substreams, &n->n);
89 /* Remove all occurrences of a substream together with the references they
90 * keep. If a substream becomes unreferenced, it is closed. If what is NULL,
91 * all substreams are removed. Returns the number of deleted entries. */
93 log_rm_substream(struct log_stream *where, struct log_stream *what)
99 CLIST_FOR_EACH_DELSAFE(simp_node *, i, where->substreams, tmp)
100 if (i->p == what || !what)
103 log_close_stream(i->p);
110 /* Return a pointer to a new stream with no handler and an empty substream list. */
112 log_new_stream(size_t size)
114 struct log_stream *l;
117 /* Initialize the data structures if needed */
120 /* Get a free stream, possibly recycling a closed one */
121 if (log_streams_free == ~0U)
123 lsbuf_grow(&log_streams, log_streams_after+1);
124 index = log_streams_after++;
125 l = log_streams.ptr[index] = xmalloc(size);
129 index = log_streams_free;
130 l = xrealloc(log_streams.ptr[index], size);
131 log_streams.ptr[index] = l;
132 log_streams_free = l->levels;
135 /* Initialize the stream */
136 bzero(l, sizeof(*l));
137 l->levels = LS_ALL_LEVELS;
138 l->regnum = LS_SET_STRNUM(index);
139 clist_init(&l->substreams);
140 return log_ref_stream(l);
143 /* Remove a reference on a stream and close it if it was the last reference.
144 * Closing automatically unlinks all substreams and closes them if they are
145 * no longer referenced. Returns 1 if the stream has been really closed. */
147 log_close_stream(struct log_stream *ls)
150 ASSERT(ls->use_count);
154 /* Unlink all subtreams */
155 log_rm_substream(ls, NULL);
157 /* Close the stream and add it to the free-list */
160 ls->levels = log_streams_free;
161 log_streams_free = LS_GET_STRNUM(ls->regnum);