Decompression demuxer. Supports gzip and bzip2 at this point.

There seems to be pretty awful bugs in stream_Demux or input or
something though. Sometimes, the input is killed almost immediately.
Other times (e.g. when trying to STOP), Close() never gets called.

modules/demux/Modules.am

@@ -29,6 +29,7 @@ SOURCES_tta = tta.c
 SOURCES_vc1 = vc1.c
 SOURCES_demux_cdg = cdg.c
 SOURCES_smf = smf.c
+SOURCES_decomp = decomp.c
 
 libvlc_LTLIBRARIES += \
 	libaiff_plugin.la \

modules/demux/decomp.c

+/*****************************************************************************
+ * decomp.c : Decompression module for vlc
+ *****************************************************************************
+ * Copyright © 2008 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU 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 <vlc_common.h>
+#include <vlc_plugin.h>
+#include <vlc_demux.h>
+#include <vlc_stream.h>
+#include <vlc_network.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <spawn.h>
+#include <sys/wait.h>
+#include <sys/ioctl.h>
+
+#include <assert.h>
+
+static int  OpenGzip (vlc_object_t *);
+static int  OpenBzip2 (vlc_object_t *);
+static void Close (vlc_object_t *);
+
+vlc_module_begin ();
+    set_description (N_("Decompression"));
+    set_category (CAT_INPUT);
+    set_subcategory (SUBCAT_INPUT_DEMUX);
+    set_capability ("demux", 20);
+    set_callbacks (OpenBzip2, Close);
+    /* TODO: shortnames */
+    /* --demux support */
+
+    add_submodule ();
+    set_callbacks (OpenGzip, Close);
+vlc_module_end ();
+
+static int Demux   (demux_t *);
+static int Control (demux_t *, int i_query, va_list args);
+
+struct demux_sys_t
+{
+    stream_t    *out;
+    vlc_thread_t thread;
+    pid_t        pid;
+    int          write_fd, read_fd;
+};
+
+static void cloexec (int fd)
+{
+    int flags = fcntl (fd, F_GETFD);
+    fcntl (fd, F_SETFD, O_CLOEXEC | (flags != -1) ? flags : 0);
+}
+
+extern char **environ;
+
+static void cleanup_fd (void *data)
+{
+    close ((intptr_t)data);
+}
+
+static void *Thread (void *data)
+{
+    demux_t *demux = data;
+    demux_sys_t *p_sys = demux->p_sys;
+    int fd = p_sys->write_fd;
+
+    vlc_cleanup_push (cleanup_fd, (void *)(intptr_t)fd);
+
+    for (;;)
+    {
+#ifdef __linux__
+        /* TODO: mmap() + vmsplice() */
+#endif
+        unsigned char buf[65536];
+        int canc = vlc_savecancel ();
+        ssize_t len = stream_Read (demux->s, buf, sizeof (buf));
+
+        vlc_restorecancel (canc);
+
+        if (len <= 0)
+            break;
+
+        for (ssize_t i = 0, j = 0; i < len; i += j)
+        {
+            j = write (fd, buf + i, len - i);
+            if (j == -1)
+            {
+                msg_Err (demux, "cannot write data (%m)");
+                break;
+            }
+        }
+    }
+
+    vlc_cleanup_run (); /* close(fd) */
+    return NULL;
+}
+
+
+#define MIN_BLOCK (1 << 10)
+#define MAX_BLOCK (1 << 20)
+/**
+ * Read data, decompress it, and forward
+ * @return -1 in case of error, 0 in case of EOF, 1 otherwise.
+ */
+static int Demux (demux_t *demux)
+{
+    demux_sys_t *p_sys = demux->p_sys;
+    int length, fd = p_sys->read_fd;
+
+#ifdef TIOCINQ
+    if (ioctl (fd, TIOCINQ, &length) == 0)
+    {
+        if (length > MAX_BLOCK)
+            length = MAX_BLOCK;
+        else
+        if (length < MIN_BLOCK)
+            length = MIN_BLOCK;
+    }
+    else
+#endif
+        length = MIN_BLOCK;
+
+    block_t *block = block_Alloc (length);
+    if (block == NULL)
+        return VLC_ENOMEM;
+
+    length = net_Read (demux, fd, NULL, block->p_buffer, length, false);
+    if (length <= 0)
+        return 0;
+    block->i_buffer = length;
+    stream_DemuxSend (p_sys->out, block);
+    return 1;
+}
+
+
+/*****************************************************************************
+ * Control:
+ *****************************************************************************/
+static int Control (demux_t *demux, int query, va_list args)
+{
+    /*demux_sys_t *p_sys = demux->p_sys;*/
+    (void)demux;
+    (void)query; (void)args;
+    return VLC_EGENERIC;
+}
+
+/**
+ * Pipe data through an external executable.
+ * @param demux the demux object.
+ * @param path path to the executable.
+ */
+static int Open (demux_t *demux, const char *path)
+{
+    demux_sys_t *p_sys = demux->p_sys = malloc (sizeof (*p_sys));
+    if (p_sys == NULL)
+        return VLC_ENOMEM;
+
+    demux->pf_demux = Demux;
+    demux->pf_control = Control;
+
+    /* I am not a big fan of the pyramid style, but I cannot think of anything
+     * better here. There are too many failure cases. */
+    int ret = VLC_EGENERIC;
+    int comp[2];
+    if (pipe (comp) == 0)
+    {
+        cloexec (comp[1]);
+        p_sys->write_fd = comp[1];
+
+        int uncomp[2];
+        if (pipe (uncomp) == 0)
+        {
+            cloexec (uncomp[0]);
+            p_sys->read_fd = uncomp[0];
+
+            posix_spawn_file_actions_t actions;
+            if (posix_spawn_file_actions_init (&actions) == 0)
+            {
+                char *const argv[] = { (char *)path, NULL };
+
+                if (!posix_spawn_file_actions_adddup2 (&actions, comp[0], 0)
+                 && !posix_spawn_file_actions_addclose (&actions, comp[0])
+                 && !posix_spawn_file_actions_adddup2 (&actions, uncomp[1], 1)
+                 && !posix_spawn_file_actions_addclose (&actions, comp[1])
+                 && !posix_spawnp (&p_sys->pid, path, &actions, NULL, argv,
+                                   environ))
+                {
+                    p_sys->out = stream_DemuxNew (demux, "", demux->out);
+                    if (p_sys->out != NULL)
+                    {
+                        if (vlc_clone (&p_sys->thread, Thread, demux,
+                                       VLC_THREAD_PRIORITY_INPUT) == 0)
+                            ret = VLC_SUCCESS;
+                        else
+                            stream_DemuxDelete (p_sys->out);
+                    }
+                    else
+                        msg_Err (demux, "Cannot create demux");
+                }
+                else
+                    msg_Err (demux, "Cannot execute %s", path);
+                posix_spawn_file_actions_destroy (&actions);
+            }
+            if (ret != VLC_SUCCESS)
+            {
+                close (comp[1]);
+                close (comp[0]);
+            }
+        }
+        if (ret != VLC_SUCCESS)
+            close (uncomp[0]);
+        close (uncomp[1]);
+    }
+    return ret;
+}
+
+
+/**
+ * Releases allocate resources.
+ */
+static void Close (vlc_object_t *obj)
+{
+    demux_t *demux = (demux_t *)obj;
+    demux_sys_t *p_sys = demux->p_sys;
+    int status;
+
+    vlc_cancel (p_sys->thread);
+    stream_DemuxDelete (p_sys->out);
+    close (p_sys->read_fd);
+    vlc_join (p_sys->thread, NULL);
+
+    msg_Dbg (obj, "waiting for PID %u", (unsigned)p_sys->pid);
+    while (waitpid (p_sys->pid, &status, 0) == -1);
+    msg_Dbg (obj, "exit status %d", status);
+
+    free (p_sys);
+}
+
+
+/**
+ * Detects gzip file format
+ */
+static int OpenGzip (vlc_object_t *obj)
+{
+    demux_t       *demux = (demux_t *)obj;
+    stream_t      *stream = demux->s;
+    const uint8_t *peek;
+
+    if (stream_Peek (stream, &peek, 3) < 3)
+        return VLC_EGENERIC;
+
+    if (memcmp (peek, "\x1f\x8b\x08", 3))
+        return VLC_EGENERIC;
+
+    msg_Dbg (obj, "detected gzip compressed stream");
+    return Open (demux, "zcat");
+}
+
+
+/**
+ * Detects bzip2 file format
+ */
+static int OpenBzip2 (vlc_object_t *obj)
+{
+    demux_t       *demux = (demux_t *)obj;
+    stream_t      *stream = demux->s;
+    const uint8_t *peek;
+
+    /* (Try to) parse the bzip2 header */
+    if (stream_Peek (stream, &peek, 10) < 10)
+        return VLC_EGENERIC;
+
+    if (memcmp (peek, "BZh", 3) || (peek[3] < '1') || (peek[3] > '9')
+     || memcmp (peek, "\x31\x41\x59\x26\x53\x59", 6))
+        return VLC_EGENERIC;
+
+    msg_Dbg (obj, "detected bzip2 compressed stream");
+    return Open (demux, "bzcat");
+}
+