Uniform audio version of the command backend. No attempt to rate-limit

[disorder] / lib / uaudio-command.c

diff --git a/lib/uaudio-command.c b/lib/uaudio-command.c
new file mode 100644 (file)
index 0000000..12a47dc
--- /dev/null
+++ b/lib/uaudio-command.c
@@ -0,0 +1,145 @@
+/*
+ * This file is part of DisOrder.
+ * Copyright (C) 2005, 2006, 2007, 2009 Richard Kettlewell
+ * Portions (C) 2007 Mark Wooding
+ *
+ * This program 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+/** @file lib/uaudio-command.c
+ * @brief Support for commmand backend */
+#include "common.h"
+
+#include <errno.h>
+#include <unistd.h>
+
+#include "syscalls.h"
+#include "log.h"
+#include "mem.h"
+#include "wstat.h"
+#include "uaudio.h"
+
+/** @brief Pipe to subprocess */
+static int command_fd;
+
+/** @brief Child process ID */
+static pid_t command_pid;
+
+static const char *const command_options[] = {
+  "command",
+  NULL
+};
+
+/** @brief Close pipe and wait for subprocess to terminate */
+static void command_wait(void) {
+  int w;
+  pid_t rc;
+  char *ws;
+
+  close(command_fd);
+  while((rc = waitpid(command_pid, &w, 0) < 0 && errno == EINTR))
+    ;
+  if(rc < 0)
+    fatal(errno, "waitpid");
+  if(w) {
+    ws = wstat(w);
+    error(0, "command subprocess %s", ws);
+    xfree(ws);
+  }
+}
+
+/** @brief Create subprocess */ 
+static void command_open(void) {
+  int pfd[2];
+  const char *command;
+
+  if(!(command = uaudio_get("command")))
+    fatal(0, "'command' not set");
+  xpipe(pfd);
+  command_pid = xfork();
+  if(!command_pid) {
+    exitfn = _exit;
+    signal(SIGPIPE, SIG_DFL);
+    xdup2(pfd[0], 0);
+    close(pfd[0]);
+    close(pfd[1]);
+    /* TODO it would be nice to set some environment variables given the sample
+     * format.  The original intended model is that you adapt DisOrder to the
+     * command you run but it'd be nice to support the opposite. */
+    execl("/bin/sh", "sh", "-c", command, (char *)0);
+    fatal(errno, "error executing /bin/sh");
+  }
+  close(pfd[0]);
+  command_pid = pfd[1];
+}
+
+/** @brief Send audio data to subprocess */
+static size_t command_play(void *buffer, size_t nsamples) {
+  const size_t bytes = nsamples * uaudio_sample_size;
+  int written = write(command_fd, buffer, bytes);
+  if(written < 0) {
+    switch(errno) {
+    case EINTR:
+      return 0;                        /* will retry */
+    case EPIPE:
+      error(0, "audio command subprocess terminated");
+      command_wait();
+      command_open();
+      return 0;                        /* will retry */
+    default:
+      fatal(errno, "error writing to audio command subprocess");
+    }
+  }
+  return written / uaudio_sample_size;
+}
+
+static void command_start(uaudio_callback *callback,
+                      void *userdata) {
+  command_open();
+  uaudio_thread_start(callback,
+                      userdata,
+                      command_play,
+                      uaudio_channels,
+                     4096 / uaudio_sample_size);
+}
+
+static void command_stop(void) {
+  uaudio_thread_stop();
+  command_wait();
+}
+
+static void command_activate(void) {
+  uaudio_thread_activate();
+}
+
+static void command_deactivate(void) {
+  uaudio_thread_deactivate();
+}
+
+const struct uaudio uaudio_command = {
+  .name = "command",
+  .options = command_options,
+  .start = command_start,
+  .stop = command_stop,
+  .activate = command_activate,
+  .deactivate = command_deactivate
+};
+
+/*
+Local Variables:
+c-basic-offset:2
+comment-column:40
+fill-column:79
+indent-tabs-mode:nil
+End:
+*/