access-imem: rewritten in-memory bit stream input (refs #8562)

This more closely matches the usual open/read/seek/close pattern.

modules/MODULES_LIST

@@ -8,6 +8,7 @@ $Id$
  * access_archive: libarchive based access and stream filter
  * access_bd: Blu-Ray Disc 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
  * access_mms: MMS over TCP, UDP and HTTP access module
  * access_mtp: MTP access module

modules/access/Makefile.am

@@ -29,10 +29,13 @@ access_LTLIBRARIES += libfilesystem_plugin.la
 libidummy_plugin_la_SOURCES = access/idummy.c
 access_LTLIBRARIES += libidummy_plugin.la
 
-libimem_plugin_la_SOURCES = access/imem.c
+libimem_plugin_la_SOURCES = access/imem-access.c
 libimem_plugin_la_LIBADD = $(LIBM)
 access_LTLIBRARIES += libimem_plugin.la
 
+libaccess_imem_plugin_la_SOURCES = access/imem.c
+access_LTLIBRARIES += libaccess_imem_plugin.la
+
 librar_plugin_la_SOURCES = access/rar/rar.c access/rar/rar.h \
 	access/rar/access.c access/rar/stream.c access/rar/module.c
 librar_plugin_la_CPPFLAGS = $(AM_CPPFLAGS)

modules/access/imem-access.c

+/*****************************************************************************
+ * imem-access.c: In-memory bit stream input for VLC
+ *****************************************************************************
+ * 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_access.h>
+#include <vlc_plugin.h>
+
+struct access_sys_t
+{
+    void *opaque;
+    ssize_t (*read_cb)(void *, unsigned char *, size_t);
+    int (*seek_cb)(void *, uint64_t);
+    void (*close_cb)(void *);
+    uint64_t size;
+};
+
+static ssize_t Read(access_t *access, uint8_t *buf, size_t len)
+{
+    access_sys_t *sys = access->p_sys;
+
+    ssize_t val = sys->read_cb(sys->opaque, buf, len);
+
+    if (val < 0) {
+        msg_Err(access, "read error");
+        val = 0;
+    }
+
+    if (val > 0) {
+        assert((size_t)val <= len);
+        access->info.i_pos += val;
+    } else
+        access->info.b_eof = true;
+
+    return val;
+}
+
+static int Seek(access_t *access, uint64_t offset)
+{
+    access_sys_t *sys = access->p_sys;
+
+    assert(sys->seek_cb != NULL);
+
+    if (sys->seek_cb(sys->opaque, offset) != 0)
+        return VLC_EGENERIC;
+
+   access->info.b_eof = false;
+   return VLC_SUCCESS;
+}
+
+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->seek_cb != NULL;
+            break;
+
+        case ACCESS_CAN_FASTSEEK:
+            *va_arg(args, bool *) = false;
+            break;
+
+        case ACCESS_CAN_PAUSE:
+        case ACCESS_CAN_CONTROL_PACE:
+            *va_arg(args, bool *) = sys->seek_cb != NULL;
+            break;
+
+        case ACCESS_GET_SIZE:
+            *va_arg(args, uint64_t *) = sys->size;
+            break;
+
+        case ACCESS_GET_PTS_DELAY:
+            *va_arg(args, int64_t *) = DEFAULT_PTS_DELAY;
+            break;
+
+        case ACCESS_SET_PAUSE_STATE:
+            break;
+
+        default:
+            return VLC_EGENERIC;
+    }
+    (void) access;
+    return VLC_SUCCESS;
+}
+
+static int open_cb_default(void *opaque, void **datap, size_t *sizep)
+{
+    *datap = opaque;
+    (void) sizep;
+    return 0;
+}
+
+static int Open(vlc_object_t *object)
+{
+    access_t *access = (access_t *)object;
+
+    access_sys_t *sys = malloc(sizeof (*sys));
+    if (unlikely(sys == NULL))
+        return VLC_ENOMEM;
+
+    int (*open_cb)(void *, void **, uint64_t *);
+    void *opaque;
+
+    opaque = var_InheritAddress(access, "imem-data");
+    open_cb = var_InheritAddress(access, "imem-open");
+    sys->opaque = NULL;
+    sys->read_cb = var_InheritAddress(access, "imem-read");
+    sys->seek_cb = var_InheritAddress(access, "imem-seek");
+    sys->close_cb = var_InheritAddress(access, "imem-close");
+    sys->size = 0;
+
+    if (open_cb == NULL)
+        open_cb = open_cb_default;
+    if (sys->read_cb == NULL)
+        goto error;
+
+    if (open_cb(opaque, &sys->opaque, &sys->size)) {
+        msg_Err(access, "open error");
+        goto error;
+    }
+
+    access->pf_read = Read;
+    access->pf_block = NULL;
+    access->pf_seek = (sys->seek_cb != NULL) ? Seek : NULL;
+    access->pf_control = Control;
+
+    access->p_sys = sys;
+    access_InitFields(access);
+    return VLC_SUCCESS;
+error:
+    free(sys);
+    return VLC_EGENERIC;
+}
+
+static void Close(vlc_object_t *object)
+{
+    access_t *access = (access_t *)object;
+    access_sys_t *sys = access->p_sys;
+
+    if (sys->close_cb != NULL)
+        sys->close_cb(sys->opaque);
+    free(sys);
+}
+
+vlc_module_begin()
+    set_shortname(N_("Nemory stream"))
+    set_description(N_("In-memory stream input"))
+    set_category(CAT_INPUT)
+    set_subcategory(SUBCAT_INPUT_ACCESS)
+
+    add_shortcut("imem")
+    set_capability("access", 0)
+    set_callbacks(Open, Close)
+vlc_module_end()

po/POTFILES.in

@@ -205,6 +205,7 @@ modules/access/gnomevfs.c
 modules/access/http.c
 modules/access/idummy.c
 modules/access/imem.c
+modules/access/imem-access.c
 modules/access/jack.c
 modules/access/linsys/linsys_hdsdi.c
 modules/access/linsys/linsys_sdi.c