2010-08-25 Sebastian Huber <sebastian.huber@embedded-brains.de>

	* libblock/include/rtems/media.h, libblock/src/media-server.c: Use
	chains instead of a message queue.

2 files changed, 62 insertions, 72 deletions

diff --git a/cpukit/libblock/include/rtems/media.h b/cpukit/libblock/include/rtems/media.h
index df37342fd6..038357c16d 100644
--- a/cpukit/libblock/include/rtems/media.h
+++ b/cpukit/libblock/include/rtems/media.h
@@ -387,9 +387,6 @@ rtems_status_code rtems_media_post_event(
  * It creates a server task with the @a priority, @a stack_size, @a modes, and
  * @a attributes parameters.
  *
- * A message queue will be used for communication with the server task which
- * may buffer up to @a message_count messages.
- *
  * Calling this function more than once will have no effects.  There is no
  * protection against concurrent access.
  *
@@ -400,8 +397,7 @@ rtems_status_code rtems_media_server_initialize(
   rtems_task_priority priority,
   size_t stack_size,
   rtems_mode modes,
-  rtems_attribute attributes,
-  uint32_t message_count
+  rtems_attribute attributes
 );
 
 /**
@@ -410,8 +406,8 @@ rtems_status_code rtems_media_server_initialize(
  * @see See rtems_media_post_event().
  *
  * @retval RTEMS_SUCCESSFUL Successful operation.
- * @retval RTEMS_UNSATISFIED Message queue is full.
- * @retval RTEMS_NO_MEMORY Not enough memory for the message.
+ * @retval RTEMS_NO_MEMORY Not enough resources to notify the media server.
+ * @retval RTEMS_NOT_CONFIGURED Media server is not initialized.
  */
 rtems_status_code rtems_media_server_post_event(
   rtems_media_event event,
diff --git a/cpukit/libblock/src/media-server.c b/cpukit/libblock/src/media-server.c
index 85b2a6db08..66f46abee9 100644
--- a/cpukit/libblock/src/media-server.c
+++ b/cpukit/libblock/src/media-server.c
@@ -21,91 +21,83 @@
  */
 
 #include <string.h>
-#include <stdio.h>
 #include <stdlib.h>
+#include <assert.h>
 
 #include <rtems.h>
 #include <rtems/chain.h>
-
 #include <rtems/media.h>
 
+#define EVENT RTEMS_EVENT_13
+
 typedef struct {
+  rtems_chain_node node;
   rtems_media_event event;
-  char *src;
+  const char *src;
   rtems_media_worker worker;
-  void *arg;
-} media_server_event;
+  void *worker_arg;
+} message;
+
+static RTEMS_CHAIN_DEFINE_EMPTY(message_chain);
 
-static rtems_id message_queue_id = RTEMS_ID_NONE;
+static rtems_id server_id = RTEMS_ID_NONE;
 
-static void rtems_media_server(rtems_task_argument arg __attribute__((unused)))
+static void media_server(rtems_task_argument arg __attribute__((unused)))
 {
   rtems_status_code sc = RTEMS_SUCCESSFUL;
 
   while (true) {
-    media_server_event msg;
-    size_t msg_size = sizeof(msg);
-
-    sc = rtems_message_queue_receive(
-      message_queue_id,
-      &msg,
-      &msg_size,
-      RTEMS_WAIT,
-      RTEMS_NO_TIMEOUT
-    );
-    if (sc != RTEMS_SUCCESSFUL) {
-      break;
-    }
+    message *msg = NULL;
 
-    rtems_media_post_event(msg.event, msg.src, NULL, msg.worker, msg.arg);
+    sc = rtems_chain_get_with_wait(
+      &message_chain,
+      EVENT,
+      RTEMS_NO_TIMEOUT,
+      (rtems_chain_node **) &msg
+    );
+    assert(sc == RTEMS_SUCCESSFUL);
+    assert(msg != NULL);
+
+    rtems_media_post_event(
+      msg->event,
+      msg->src,
+      NULL,
+      msg->worker,
+      msg->worker_arg
+    );
 
-    free(msg.src);
+    free(msg);
   }
-
-  rtems_task_delete(RTEMS_SELF);
 }
 
 rtems_status_code rtems_media_server_initialize(
   rtems_task_priority priority,
   size_t stack_size,
   rtems_mode modes,
-  rtems_attribute attributes,
-  uint32_t message_count
+  rtems_attribute attributes
 )
 {
   rtems_status_code sc = RTEMS_SUCCESSFUL;
-  rtems_id task_id = RTEMS_ID_NONE;
 
-  if (message_queue_id == RTEMS_ID_NONE) {
+  if (server_id == RTEMS_ID_NONE) {
     sc = rtems_media_initialize();
     if (sc != RTEMS_SUCCESSFUL) {
       goto error;
     }
 
-    sc = rtems_message_queue_create(
-      rtems_build_name('M', 'D', 'I', 'A'),
-      message_count,
-      sizeof(media_server_event),
-      RTEMS_DEFAULT_ATTRIBUTES,
-      &message_queue_id
-    );
-    if (sc != RTEMS_SUCCESSFUL) {
-      goto error;
-    }
-
     sc = rtems_task_create(
       rtems_build_name('M', 'D', 'I', 'A'),
       priority,
       stack_size,
       modes,
       attributes,
-      &task_id
+      &server_id
     );
     if (sc != RTEMS_SUCCESSFUL) {
       goto error;
     }
 
-    sc = rtems_task_start(task_id, rtems_media_server, 0);
+    sc = rtems_task_start(server_id, media_server, 0);
     if (sc != RTEMS_SUCCESSFUL) {
       goto error;
     }
@@ -115,12 +107,10 @@ rtems_status_code rtems_media_server_initialize(
 
 error:
 
-  if (task_id != RTEMS_ID_NONE) {
-    rtems_task_delete(task_id);
+  if (server_id != RTEMS_ID_NONE) {
+    rtems_task_delete(server_id);
   }
 
-  rtems_message_queue_delete(message_queue_id);
-
   return RTEMS_NO_MEMORY;
 }
 
@@ -128,31 +118,35 @@ rtems_status_code rtems_media_server_post_event(
   rtems_media_event event,
   const char *src,
   rtems_media_worker worker,
-  void *arg
+  void *worker_arg
 )
 {
   rtems_status_code sc = RTEMS_SUCCESSFUL;
-  media_server_event msg = {
-    .event = event,
-    .src = strdup(src),
-    .worker = worker,
-    .arg = arg
-  };
-
-  if (msg.src == NULL) {
-    return RTEMS_NO_MEMORY;
-  }
+  size_t src_size = strlen(src) + 1;
+  message *msg = malloc(sizeof(*msg) + src_size);
+
+  if (msg != NULL) {
+    char *s = (char *) msg + sizeof(*msg);
 
-  sc = rtems_message_queue_send(
-    message_queue_id,
-    &msg,
-    sizeof(msg)
-  );
-  if (sc != RTEMS_SUCCESSFUL) {
-    free(msg.src);
+    memcpy(s, src, src_size);
 
-    return RTEMS_UNSATISFIED;
+    msg->event = event;
+    msg->src = s;
+    msg->worker = worker;
+    msg->worker_arg = worker_arg;
+
+    sc = rtems_chain_append_with_notification(
+      &message_chain,
+      &msg->node,
+      server_id,
+      EVENT
+    );
+    if (sc != RTEMS_SUCCESSFUL) {
+      sc = RTEMS_NOT_CONFIGURED;
+    }
+  } else {
+    sc = RTEMS_NO_MEMORY;
   }
 
-  return RTEMS_SUCCESSFUL;
+  return sc;
 }