From 0640d9e42143dedcfffbd496e34431083ba5c917 Mon Sep 17 00:00:00 2001
From: Andre Noll <maan@systemlinux.org>
Date: Sat, 19 Dec 2009 21:04:56 +0100
Subject: [PATCH] Add more documentation.

This adds documentation of load_afd(), aft_init(), enum play_mode, and enum
afs_server_code.
---
 afs.h | 25 +++++++++++++++++++++++--
 aft.c | 17 +++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/afs.h b/afs.h
index aeaf8fb8..b89ba618 100644
--- a/afs.h
+++ b/afs.h
@@ -97,7 +97,13 @@ struct afs_table {
 		void *data);
 };
 
-enum play_mode {PLAY_MODE_MOOD, PLAY_MODE_PLAYLIST};
+/** How audio files are selected by afs. */
+enum play_mode {
+	/** Admissible files are determined by a mood definition. */
+	PLAY_MODE_MOOD,
+	/** All listed files are admissible. */
+	PLAY_MODE_PLAYLIST,
+};
 
 /**
  * Data about one audio file.
@@ -125,10 +131,25 @@ struct audio_file_data {
 	struct afh_info afhi;
 };
 
+/**
+ * Codes used for communication between the server and the afs process.
+ *
+ * Before forking the afs child, para_server creates a bidirectional pipe
+ * through which both processes communicate. Usually para_server requests a new
+ * audio in order to start streaming or when the end of the current audio file
+ * has been reached.  The afs process responds to such a request by sending
+ * back an eight byte buffer. The first four bytes is the uint32_t
+ * representation of the code, usually \p NEXT_AUDIO_FILE if an admissible
+ * audio file was found, successfully opened and verified. The other four bytes
+ * represent the shared memory id of the shared memory area that contains
+ * details about the audio file to be streamed next. The open file descriptor
+ * of that file is also passed from afs to para_server through the same pipe.
+ */
 enum afs_server_code {
+	/** An audio file was successfully opened. */
 	NEXT_AUDIO_FILE,
+	/** No admissible audio file was found. */
 	NO_ADMISSIBLE_FILES,
-	AFD_CHANGE
 };
 
 /** Flags passed to for_each_matching_row(). */
diff --git a/aft.c b/aft.c
index 39e94a94..10337349 100644
--- a/aft.c
+++ b/aft.c
@@ -652,6 +652,18 @@ err:
 	return ret;
 }
 
+/**
+ * Extract a afd stored in a shared memory area.
+ *
+ * Attach the shared memory area given by \a shmid, load the audio file data
+ * stored therein and detach the area afterwards.  Called by vss, after
+ * receiving a positive response to the request for the next audio file.
+ +
+ * \param shmid The identifier of the shared memory area containing the afd.
+ * \param afd Result pointer.
+ *
+ * \return Standard.
+ */
 int load_afd(int shmid, struct audio_file_data *afd)
 {
 	void *shm_afd;
@@ -2610,6 +2622,11 @@ static int aft_event_handler(enum afs_events event, struct para_buffer *pb,
 	}
 }
 
+/**
+ * Initialize the audio file table.
+ *
+ * \param t Pointer to the structure to be initialized.
+ */
 void aft_init(struct afs_table *t)
 {
 	t->open = aft_open;
-- 
2.39.2