Introduce prepare_writer_node().

[paraslash.git] / write_common.c

diff --git a/write_common.c b/write_common.c
index 8e4d5aa62a30e9c69d34dc31231da78afde193a5..ff8999f63eb8b67312db89d07688c93b404d05d0 100644 (file)
--- a/write_common.c
+++ b/write_common.c
@@ -236,6 +236,51 @@ struct writer_node_group *setup_default_wng(void)
        wng->writer_nodes[0].conf = writers[DEFAULT_WRITER].parse_config("");
        return wng;
 }
+
+/**
+ * Setup a writer node with the default writer.
+ *
+ * If arg is \p NULL, the OS-dependent default writer is used with an empty
+ * configuration string.  It defaults to alsa for Linux, osx for OS X, oss for
+ * *BSD and the file writer if neither of these is supported.
+ *
+ * Once the writer configuration has been retrieved, a writer node is created,
+ * its buffer tree node is added to the buffer tree as a child of the given
+ * parent.
+ *
+ * Finally, the new writer node's taks structure is initialized and registered
+ * to the paraslash scheduler.
+ *
+ * \return A pointer to the allocated writer node group.
+ */
+struct writer_node *setup_writer_node(const char *arg, struct btr_node *parent)
+{
+       struct writer_node *wn = para_calloc(sizeof(*wn));
+       struct writer *w;
+       const char *name;
+
+       if (arg)
+               wn->conf = check_writer_arg(arg, &wn->writer_num);
+       else {
+               wn->writer_num = DEFAULT_WRITER;
+               wn->conf = writers[DEFAULT_WRITER].parse_config("");
+       }
+       if (!wn->conf) {
+               free(wn);
+               return NULL;
+       }
+       w = writers + wn->writer_num;
+       name = writer_names[wn->writer_num];
+       wn->btrn = btr_new_node(name, parent, w->execute, wn);
+       sprintf(wn->task.status, "%s", name);
+       w->open(wn);
+       wn->task.post_select = w->post_select_btr;
+       wn->task.pre_select = w->pre_select_btr;
+       register_task(&wn->task);
+       return wn;
+}
+
+
 /**
  * Print the help text of all writers to stdout.
  *
@@ -258,3 +303,20 @@ void print_writer_helps(int detailed)
                ggo_print_help(&w->help, detailed);
        }
 }
+
+int prepare_writer_node(struct writer_node *wn)
+{
+       struct btr_node *btrn = wn->btrn;
+       size_t iqs;
+
+       if (btr_eof(btrn))
+               return -E_WRITE_COMMON_EOF;
+       iqs = btr_get_input_queue_size(btrn);
+       if (iqs < wn->min_iqs && !btr_no_parent(btrn))
+               return 0;
+       assert(iqs != 0);
+       /* avoid "buffer too small" errors from the decoder */
+       btr_merge(btrn, wn->min_iqs);
+       return 1;
+}
+