core: add a playlist demuxer

Modeled after the old playlist_parser.c, but actually new code, and it
works a bit differently.

Demuxers (and sometimes streams) are the component that should be used
to open files and to determine the file format. This was already done
for subtitles, but playlists still use a separate code path.

1 files changed, 136 insertions, 0 deletions

diff --git a/demux/demux_playlist.c b/demux/demux_playlist.c
new file mode 100644
index 0000000000..b924140497
--- /dev/null
+++ b/demux/demux_playlist.c
@@ -0,0 +1,136 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * mpv 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "mpvcore/mp_common.h"
+#include "mpvcore/options.h"
+#include "mpvcore/mp_msg.h"
+#include "mpvcore/playlist.h"
+#include "mpvcore/path.h"
+#include "stream/stream.h"
+#include "demux.h"
+
+#define PROBE_SIZE (8 * 1024)
+
+struct pl_parser {
+    struct stream *s;
+    char buffer[8 * 1024];
+    int utf16;
+    struct playlist *pl;
+    bool probing;
+};
+
+static char *pl_get_line0(struct pl_parser *p)
+{
+    char *res = stream_read_line(p->s, p->buffer, sizeof(p->buffer), p->utf16);
+    if (res) {
+        int len = strlen(res);
+        if (len > 0 && res[len - 1] == '\n')
+            res[len - 1] = '\0';
+    }
+    return res;
+}
+
+static bstr pl_get_line(struct pl_parser *p)
+{
+    return bstr0(pl_get_line0(p));
+}
+
+static void pl_add(struct pl_parser *p, bstr entry)
+{
+    char *s = bstrto0(NULL, entry);
+    playlist_add_file(p->pl, s);
+    talloc_free(s);
+}
+
+static bool pl_eof(struct pl_parser *p)
+{
+    return p->s->eof;
+}
+
+static int parse_m3u(struct pl_parser *p)
+{
+    bstr line = bstr_strip(pl_get_line(p));
+    if (!bstr_equals0(line, "#EXTM3U"))
+        return -1;
+    if (p->probing)
+        return 0;
+    while (!pl_eof(p)) {
+        line = bstr_lstrip(pl_get_line(p));
+        if (line.len == 0 || bstr_startswith0(line, "#"))
+            continue;
+        pl_add(p, line);
+    }
+    return 0;
+}
+
+struct pl_format {
+    const char *name;
+    int (*parse)(struct pl_parser *p);
+};
+
+static const struct pl_format formats[] = {
+    {"m3u", parse_m3u},
+};
+
+static const struct pl_format *probe_pl(struct pl_parser *p, bool force)
+{
+    int64_t start = stream_tell(p->s);
+    for (int n = 0; n < MP_ARRAY_SIZE(formats); n++) {
+        const struct pl_format *fmt = &formats[n];
+        stream_seek(p->s, start);
+        if (fmt->parse(p) >= 0)
+            return fmt;
+    }
+    return NULL;
+}
+
+static int open_file(struct demuxer *demuxer, enum demux_check check)
+{
+    bool force = check < DEMUX_CHECK_UNSAFE || check == DEMUX_CHECK_REQUEST;
+
+    struct pl_parser *p = talloc_zero(NULL, struct pl_parser);
+    p->pl = talloc_zero(p, struct playlist);
+
+    bstr probe_buf = stream_peek(demuxer->stream, PROBE_SIZE);
+    p->s = open_memory_stream(probe_buf.start, probe_buf.len);
+    p->utf16 = stream_skip_bom(p->s);
+    p->probing = true;
+    const struct pl_format *fmt = probe_pl(p, force);
+    free_stream(p->s);
+    playlist_clear(p->pl);
+    if (!fmt) {
+        talloc_free(p);
+        return -1;
+    }
+
+    p->probing = false;
+    p->s = demuxer->stream;
+    p->utf16 = stream_skip_bom(p->s);
+    bool ok = fmt->parse(p) >= 0;
+    if (ok)
+        playlist_add_base_path(p->pl, mp_dirname(demuxer->filename));
+    demuxer->playlist = talloc_steal(demuxer, p->pl);
+    demuxer->filetype = fmt->name;
+    talloc_free(p);
+    return ok ? 0 : -1;
+}
+
+const struct demuxer_desc demuxer_desc_playlist = {
+    .name = "playlist",
+    .desc = "Playlist file",
+    .open = open_file,
+};