lavf: add a basic API for playlist input.

5 files changed, 224 insertions, 1 deletions

diff --git a/libavformat/Makefile b/libavformat/Makefile
index 0a30c6ec1a..10943605d2 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -10,6 +10,7 @@ OBJS = allformats.o         \
        metadata.o           \
        options.o            \
        os_support.o         \
+       playlist.o           \
        sdp.o                \
        seek.o               \
        utils.o              \
diff --git a/libavformat/avformat.h b/libavformat/avformat.h
index cc5457e8a2..ee82f5018d 100644
--- a/libavformat/avformat.h
+++ b/libavformat/avformat.h
@@ -182,6 +182,58 @@ attribute_deprecated void av_metadata_free(AVDictionary **m);
  */
 #endif
 
+/**
+ * @defgroup playlist_api Public Playlist API
+ * @{
+ * Playlist files work differently from "normal" media files in that they
+ * don't contain actual playable data, only links to it. When libavformat
+ * opens a playlist, it will create and populate the AVFormatContext.plist
+ * field.
+ *
+ * Each playlist element contains one or more URLs pointing to media files
+ * to be played. Multiple URLs under one entry should point to different
+ * copies/versions of the same content.
+ *
+ * Opening/closing the playlist contents and reading the contents is up to
+ * the caller. A convenience function av_playlist_advance() is provided to
+ * simplify this. AVPlaylistContext.cur_elem and AVPlaylistElement.fc fields
+ * are managed by this function and are unset if the caller chooses not to
+ * use it.
+ */
+
+typedef struct AVPlaylistElement {
+    uint8_t **filenames;            /** A list of URLs for this element in the order of preference. */
+    int    nb_filenames;            /** Number of filenames. */
+    AVDictionary *metadata;
+
+    int64_t start, end;             /** Start and end times for this element in AV_TIME_BASE units.
+                                        AV_NOPTS_VALUE if unspecified. */
+
+    struct AVFormatContext *fc;     /** AVFormatContext for this element. */
+} AVPlaylistElement;
+
+typedef struct AVPlaylistContext {
+    AVPlaylistElement **elems;
+    int              nb_elems;
+
+    int cur_elem;
+} AVPlaylistContext;
+
+/**
+ * Close current open element in the playlist (if any) and advance to another
+ * one.
+ *
+ * @param s the playlist in which to advance
+ * @param offset opened element will be offset elements from current.
+ * @param options options to pass to avformat_open_input().
+ *
+ * @return index of the opened element on success, a negative number on error.
+ */
+int av_playlist_advance(struct AVFormatContext *s, int offset, AVDictionary **options);
+
+/**
+ * @}
+ */
 
 /* packet functions */
 
@@ -870,6 +922,12 @@ typedef struct AVFormatContext {
      * - decoding: Set by user.
      */
     int error_recognition;
+
+    /*
+     * If this stream is a playlist, this holds the playlist-relevant
+     * data. NULL otherwise.
+     */
+    AVPlaylistContext *plist;
 } AVFormatContext;
 
 typedef struct AVPacketList {
diff --git a/libavformat/playlist.c b/libavformat/playlist.c
new file mode 100644
index 0000000000..db91a7ca73
--- /dev/null
+++ b/libavformat/playlist.c
@@ -0,0 +1,110 @@
+/*
+ * Internal playlist functions.
+ * Copyright (c) 2011 Anton Khirnov
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "avformat.h"
+#include "internal.h"
+#include "playlist.h"
+#include "libavutil/mem.h"
+
+AVPlaylistContext *ff_playlist_alloc(void)
+{
+    AVPlaylistContext *p = av_mallocz(sizeof(*p));
+    if (!p)
+        return NULL;
+
+    p->cur_elem = -1;
+
+    return p;
+}
+
+void ff_playlist_free(AVPlaylistContext **pls)
+{
+    AVPlaylistContext *p = *pls;
+
+    if (p) {
+        while (p->nb_elems--) {
+            AVPlaylistElement *e = p->elems[p->nb_elems];
+            while (e->nb_filenames--)
+                av_freep(&e->filenames[e->nb_filenames]);
+            av_freep(&e->filenames);
+            av_freep(&p->elems[p->nb_elems]);
+        }
+        av_freep(pls);
+    }
+}
+
+AVPlaylistElement *ff_playlist_add_entry(AVFormatContext *s, const uint8_t *filename)
+{
+    AVPlaylistElement *elem;
+    uint8_t *tmp;
+
+    if (!s->plist && !(s->plist = ff_playlist_alloc()))
+        return NULL;
+
+    if (!(elem = av_mallocz(sizeof(*elem))))
+        return NULL;
+    tmp = av_strdup(filename);
+    dynarray_add(&elem->filenames, &elem->nb_filenames, tmp);
+    dynarray_add(&s->plist->elems, &s->plist->nb_elems, elem);
+    return elem;
+}
+
+int av_playlist_advance(AVFormatContext *s, int offset, AVDictionary **options)
+{
+    AVPlaylistContext *plist = s->plist;
+    AVPlaylistElement *elem;
+    int ret, i;
+
+    if (!plist)
+        return AVERROR(EINVAL);
+
+    if (plist->cur_elem >= 0) {
+        av_close_input_file(plist->elems[plist->cur_elem]->fc);
+        plist->elems[plist->cur_elem]->fc = NULL;
+        plist->cur_elem += offset;
+    } else
+        plist->cur_elem = (offset >= 0 ? -1 : plist->nb_elems) + offset;
+
+    if (plist->cur_elem >= plist->nb_elems || plist->cur_elem < 0) {
+        plist->cur_elem = -1;
+        return AVERROR_EOF;
+    }
+
+    elem = plist->elems[plist->cur_elem];
+    for (i = 0; i < elem->nb_filenames; i++) {
+        AVDictionary *tmp = NULL;
+
+        if (options && i + 1 < elem->nb_filenames)
+            av_dict_copy(&tmp, *options, 0);        // save the options for the next attempt if needed
+
+        ret = avformat_open_input(&elem->fc, plist->elems[plist->cur_elem]->filenames[i],
+                                  NULL, options);
+        if (ret >= 0) {
+            av_dict_free(&tmp);
+            return plist->cur_elem;
+        }
+        av_dict_free(options);
+        *options = tmp;
+    }
+    av_log(s, AV_LOG_ERROR, "Could not open element %d.\n", plist->cur_elem);
+    plist->cur_elem = -1;
+    return ret;
+}
diff --git a/libavformat/playlist.h b/libavformat/playlist.h
new file mode 100644
index 0000000000..074713277c
--- /dev/null
+++ b/libavformat/playlist.h
@@ -0,0 +1,33 @@
+/*
+ * Internal playlist header.
+ * Copyright (c) 2011 Anton Khirnov
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVFORMAT_PLAYLIST_H
+#define AVFORMAT_PLAYLIST_H
+
+#include "avformat.h"
+
+AVPlaylistContext *ff_playlist_alloc(void);
+
+void ff_playlist_free(AVPlaylistContext **pls);
+
+AVPlaylistElement *ff_playlist_add_entry(AVFormatContext *s, const uint8_t *filename);
+
+#endif // AVFORMAT_PLAYLIST_H
diff --git a/libavformat/utils.c b/libavformat/utils.c
index e4e6d24e53..bcd26668ca 100644
--- a/libavformat/utils.c
+++ b/libavformat/utils.c
@@ -30,6 +30,7 @@
 #include "libavutil/pixdesc.h"
 #include "metadata.h"
 #include "id3v2.h"
+#include "playlist.h"
 #include "libavutil/avstring.h"
 #include "libavutil/mathematics.h"
 #include "riff.h"
@@ -2596,6 +2597,15 @@ int av_read_pause(AVFormatContext *s)
 
 void av_close_input_stream(AVFormatContext *s)
 {
+    if (s->plist) {
+        int i;
+        for (i = 0; i < s->plist->nb_elems; i++)
+            if (s->plist->elems[i]->fc) {
+                av_close_input_file(s->plist->elems[i]->fc);
+                s->plist->elems[i]->fc = NULL;
+            }
+        ff_playlist_free(&s->plist);
+    }
     flush_packet_queue(s);
     if (s->iformat->read_close)
         s->iformat->read_close(s);
@@ -3332,7 +3342,7 @@ void av_dump_format(AVFormatContext *ic,
                     const char *url,
                     int is_output)
 {
-    int i;
+    int i, j;
     uint8_t *printed = ic->nb_streams ? av_mallocz(ic->nb_streams) : NULL;
     if (ic->nb_streams && !printed)
         return;
@@ -3343,6 +3353,17 @@ void av_dump_format(AVFormatContext *ic,
             is_output ? ic->oformat->name : ic->iformat->name,
             is_output ? "to" : "from", url);
     dump_metadata(NULL, ic->metadata, "  ");
+    if (ic->plist) {
+        av_log(NULL, AV_LOG_INFO, "  Playlist:\n");
+        for (i = 0; i < ic->plist->nb_elems; i++) {
+            AVPlaylistElement *elem = ic->plist->elems[i];
+            av_log(NULL, AV_LOG_INFO, "    Element #%d:", i);
+            for (j = 0; j < elem->nb_filenames; j++)
+                av_log(NULL, AV_LOG_INFO, "      %s\n", elem->filenames[j]);
+            dump_metadata(NULL, elem->metadata, "      ");
+        }
+        return;
+    }
     if (!is_output) {
         av_log(NULL, AV_LOG_INFO, "  Duration: ");
         if (ic->duration != AV_NOPTS_VALUE) {