concat: access to concatenate multiple access objects

Usage:

$ vlc concat:// :concat=URL1,URL2,....URLn

Note: As for the existing input-slave and input-list options, URLs are
assumed to not contain unencoded commas. This is usually the case but
not strictly warranted as the comma is a sub-delimiter.

NEWS

@@ -26,6 +26,7 @@ Access:
  * New WASAPI audio capture module on Windows
  * SMB/FTP/SFTP accesses can list directories
  * Support for SAT>IP server dialect for RTSP (satip://)
+ * New "concat" access module for concatenating byte streams
 
 Decoder:
  * OMX GPU-zerocopy support for decoding and display on Android using OpenMax IL

modules/MODULES_LIST

@@ -7,6 +7,7 @@ $Id$
  * access_alsa: Alsa access module
  * access_archive: libarchive based access and stream filter
  * access_bd: Blu-Ray Disc access
+ * access_concat: concatenated access
  * access_eyetv: Access module to connect to our plugin running within EyeTV
  * access_imem: memory bitstream access module
  * access_jack: JACK audio input module

modules/access/Makefile.am

@@ -466,6 +466,9 @@ endif
 
 ### Misc ###
 
+libaccess_concat_plugin_la_SOURCES = access/concat.c
+access_LTLIBRARIES += libaccess_concat_plugin.la
+
 libgnomevfs_plugin_la_SOURCES = access/gnomevfs.c
 libgnomevfs_plugin_la_CFLAGS = $(AM_CFLAGS) $(GNOMEVFS_CFLAGS)
 libgnomevfs_plugin_la_LIBADD = $(GNOMEVFS_LIBS)

modules/access/concat.c

+/*****************************************************************************
+ * concat.c: Concatenated inputs
+ *****************************************************************************
+ * Copyright (C) 2015 Rémi Denis-Courmont
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
+ *****************************************************************************/
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <assert.h>
+
+#include <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_access.h>
+
+struct access_entry
+{
+    struct access_entry *next;
+    char mrl[1];
+};
+
+struct access_sys_t
+{
+    access_t *access;
+    struct access_entry *next;
+    struct access_entry *first;
+    bool can_seek;
+    bool can_seek_fast;
+    bool can_pause;
+    bool can_control_pace;
+    uint64_t size;
+    int64_t caching;
+};
+
+static access_t *GetAccess(access_t *access)
+{
+    access_sys_t *sys = access->p_sys;
+    access_t *a = sys->access;
+
+    if (a != NULL)
+    {
+        if (!vlc_access_Eof(a))
+            return a;
+
+        vlc_access_Delete(a);
+        sys->access = NULL;
+    }
+
+    if (sys->next == NULL)
+    {
+error:
+        access->info.b_eof = true;
+        return NULL;
+    }
+
+    a = vlc_access_NewMRL(VLC_OBJECT(access), sys->next->mrl);
+    if (a == NULL)
+        goto error;
+
+    sys->access = a;
+    sys->next = sys->next->next;
+    return a;
+}
+
+static ssize_t Read(access_t *access, uint8_t *buf, size_t len)
+{
+    access_t *a = GetAccess(access);
+    if (a == NULL)
+        return 0;
+
+    /* NOTE: Since we recreate the underlying access, the access method can
+     * change. We need to check it. For instance, a path could point to a
+     * regular file during Open() yet point to a directory here and now. */
+    if (unlikely(a->pf_read == NULL))
+    {
+        access->info.b_eof = true;
+        return 0;
+    }
+
+    ssize_t ret = vlc_access_Read(a, buf, len);
+    if (ret >= 0)
+        access->info.i_pos += ret;
+    return ret;
+}
+
+static block_t *Block(access_t *access)
+{
+    access_t *a = GetAccess(access);
+    if (a == NULL)
+        return NULL;
+
+    if (likely(a->pf_block != NULL))
+        return vlc_access_Block(a);
+
+    if (a->pf_read == NULL)
+    {
+        access->info.b_eof = true;
+        return NULL;
+    }
+
+    /* Emulate pf_block in case of mixed pf_read and bf_block */
+    block_t *block = block_Alloc(4096);
+    if (unlikely(block == NULL))
+        return NULL;
+
+    ssize_t ret = vlc_access_Read(a, block->p_buffer, block->i_buffer);
+    if (ret >= 0)
+    {
+        block->i_buffer = ret;
+        access->info.i_pos += ret;
+    }
+    else
+    {
+        block_Release(block);
+        block = NULL;
+    }
+    return block;
+}
+
+static int Seek(access_t *access, uint64_t position)
+{
+    access_sys_t *sys = access->p_sys;
+
+    if (sys->access != NULL)
+    {
+        vlc_access_Delete(sys->access);
+        sys->access = NULL;
+    }
+
+    sys->next = sys->first;
+    access->info.i_pos = 0;
+
+    for (;;)
+    {
+        access_t *a = GetAccess(access);
+        if (a == NULL)
+            break;
+
+        bool can_seek;
+        access_Control(a, ACCESS_CAN_SEEK, &can_seek);
+        if (!can_seek)
+            break;
+
+        uint64_t size = access_GetSize(a);
+
+        if (position - access->info.i_pos < size)
+        {
+            if (vlc_access_Seek(a, position - access->info.i_pos))
+                break;
+
+            access->info.i_pos = position;
+            return VLC_SUCCESS;
+        }
+
+        access->info.i_pos += size;
+        vlc_access_Delete(a);
+        sys->access = NULL;
+    }
+
+    return VLC_EGENERIC;
+}
+
+static int Control(access_t *access, int query, va_list args)
+{
+    access_sys_t *sys = access->p_sys;
+
+    switch (query)
+    {
+        case ACCESS_CAN_SEEK:
+            *va_arg(args, bool *) = sys->can_seek;
+            break;
+        case ACCESS_CAN_FASTSEEK:
+            *va_arg(args, bool *) = sys->can_seek_fast;
+            break;
+        case ACCESS_CAN_PAUSE:
+            *va_arg(args, bool *) = sys->can_pause;
+            break;
+        case ACCESS_CAN_CONTROL_PACE:
+            *va_arg(args, bool *) = sys->can_control_pace;
+            break;
+        case ACCESS_GET_SIZE:
+            *va_arg(args, uint64_t *) = sys->size;
+            break;
+        case ACCESS_GET_PTS_DELAY:
+            *va_arg(args, int64_t *) = sys->caching;
+            break;
+
+        case ACCESS_GET_SIGNAL:
+        case ACCESS_SET_PAUSE_STATE:
+            return access_vaControl(sys->access, query, args);
+
+        default:
+            return VLC_EGENERIC;
+    }
+    return VLC_SUCCESS;
+}
+
+static int Open(vlc_object_t *obj)
+{
+    access_t *access = (access_t *)obj;
+
+    char *list = var_InheritString(access, "concat-list");
+    if (list == NULL)
+        return VLC_EGENERIC;
+
+    access_sys_t *sys = malloc(sizeof (*sys));
+    if (unlikely(sys == NULL))
+    {
+        free(list);
+        return VLC_ENOMEM;
+    }
+
+    bool read_cb = true;
+
+    sys->access = NULL;
+    sys->can_seek = true;
+    sys->can_seek_fast = true;
+    sys->can_pause = true;
+    sys->can_control_pace = true;
+    sys->size = 0;
+    sys->caching = 0;
+
+    struct access_entry **pp = &sys->first;
+
+    for (char *buf, *mrl = strtok_r(list, ",", &buf);
+         mrl != NULL;
+         mrl = strtok_r(NULL, ",", &buf))
+    {
+        size_t mlen = strlen(mrl);
+        struct access_entry *e = malloc(sizeof (*e) + mlen);
+        if (unlikely(e == NULL))
+            break;
+
+        access_t *a = vlc_access_NewMRL(obj, mrl);
+        if (a == NULL)
+        {
+            msg_Err(access, "cannot concatenate location %s", mrl);
+            free(e);
+            continue;
+        }
+
+        if (a->pf_read == NULL)
+        {
+            if (a->pf_block == NULL)
+            {
+                msg_Err(access, "cannot concatenate directory %s", mrl);
+                vlc_access_Delete(a);
+                free(e);
+                continue;
+            }
+            read_cb = false;
+        }
+
+        *pp = e;
+        e->next = NULL;
+        memcpy(e->mrl, mrl, mlen + 1);
+
+        if (sys->can_seek)
+            access_Control(a, ACCESS_CAN_SEEK, &sys->can_seek);
+        if (sys->can_seek_fast)
+            access_Control(a, ACCESS_CAN_FASTSEEK, &sys->can_seek_fast);
+        if (sys->can_pause)
+            access_Control(a, ACCESS_CAN_PAUSE, &sys->can_pause);
+        if (sys->can_control_pace)
+            access_Control(a, ACCESS_CAN_CONTROL_PACE, &sys->can_control_pace);
+
+        sys->size += access_GetSize(a);
+
+        int64_t caching;
+        access_Control(a, ACCESS_GET_PTS_DELAY, &caching);
+        if (caching > sys->caching)
+            sys->caching = caching;
+
+        vlc_access_Delete(a);
+        pp = &e->next;
+    }
+
+    free(list);
+    *pp = NULL;
+    sys->next = sys->first;
+
+    access_InitFields(access);
+    access->pf_read = read_cb ? Read : NULL;
+    access->pf_block = read_cb ? NULL : Block;
+    access->pf_seek = Seek;
+    access->pf_control = Control;
+    access->p_sys = sys;
+
+    return VLC_SUCCESS;
+}
+
+static void Close(vlc_object_t *obj)
+{
+    access_t *access = (access_t *)obj;
+    access_sys_t *sys = access->p_sys;
+
+    if (sys->access != NULL)
+        vlc_access_Delete(sys->access);
+
+    for (struct access_entry *e = sys->first, *next; e != NULL; e = next)
+    {
+        next = e->next;
+        free(e);
+    }
+
+    free(sys);
+}
+
+#define INPUT_LIST_TEXT N_("Inputs list")
+#define INPUT_LIST_LONGTEXT N_( \
+    "Comma-separated list of input URLs to concatenate.")
+
+vlc_module_begin()
+    set_shortname(N_("Concatenation"))
+    set_description(N_("Concatenated inputs"))
+    set_category(CAT_INPUT)
+    set_subcategory(SUBCAT_INPUT_ACCESS)
+    add_string("concat-list", NULL, INPUT_LIST_TEXT, INPUT_LIST_LONGTEXT, true)
+    set_capability("access", 0)
+    set_callbacks(Open, Close)
+    add_shortcut("concast", "list")
+vlc_module_end()

po/POTFILES.in

@@ -184,6 +184,7 @@ modules/access/avio.h
 modules/access/bd/bd.c
 modules/access/bluray.c
 modules/access/cdda.c
+modules/access/concat.c
 modules/access/dc1394.c
 modules/access/dcp/dcp.cpp
 modules/access/decklink.cpp