degesch: prepare for user/channel buffers

That is, prepare all the required data structures and their relations.

I'm not particularly good at this, so let's just hope it will work out.

degesch.c

@@ -91,7 +91,7 @@ static struct config_item g_config_table[] =
 // --- Application data --------------------------------------------------------
 
 // All text stored in our data structures is encoded in UTF-8.
-// Or at least should be.
+// Or at least should be.  The exception is IRC identifiers.
 
 /// Shorthand to set an error and return failure from the function
 #define FAIL(...)                                                              \
@@ -100,27 +100,163 @@ static struct config_item g_config_table[] =
 		return false;                                                          \
 	BLOCK_END
 
+static void user_unref (void *p);
+static void channel_unref (void *p);
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
-struct nick_info
+struct user_channel
 {
-	char *nickname;                     ///< Literal nickname
+	LIST_HEADER (struct user_channel)
-	char mode_char;                     ///< Op/voice/... character
-	bool away;                          ///< User is away
 
-	// XXX: maybe a good candidate for deduplication (away status)
+	struct channel *channel;            ///< Reference to channel
 };
 
-static void
+static struct user_channel *
-nick_info_destroy (void *p)
+user_channel_new (void)
 {
-	struct nick_info *self = p;
+	struct user_channel *self = xcalloc (1, sizeof *self);
-	free (self->nickname);
+	return self;
+}
+
+static void
+user_channel_destroy (void *p)
+{
+	struct user_channel *self = p;
+	channel_unref (self->channel);
 	free (self);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
+// We keep references to user information in channels and buffers,
+// as well as in the name lookup table.
+
+struct user
+{
+	size_t ref_count;                   ///< Reference count
+
+	// TODO: eventually a reference to the server
+
+	char *nickname;                     ///< Literal nickname
+	// TODO: write code to poll for the away status
+	bool away;                          ///< User is away
+
+	struct user_channel *channels;      ///< Channels the user is on
+};
+
+static struct user *
+user_new (void)
+{
+	struct user *self = xcalloc (1, sizeof *self);
+	self->ref_count = 1;
+	return self;
+}
+
+static void
+user_destroy (struct user *self)
+{
+	free (self->nickname);
+	LIST_FOR_EACH (struct user_channel, iter, self->channels)
+		user_channel_destroy (iter);
+	free (self);
+}
+
+static struct user *
+user_ref (struct user *self)
+{
+	self->ref_count++;
+	return self;
+}
+
+static void
+user_unref (void *p)
+{
+	struct user *self = p;
+	if (!--self->ref_count)
+		user_destroy (self);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+struct channel_user
+{
+	LIST_HEADER (struct channel_user)
+
+	struct user *user;                  ///< Reference to user
+	char mode_char;                     ///< Op/voice/... character, or zero
+};
+
+static struct channel_user *
+channel_user_new (void)
+{
+	struct channel_user *self = xcalloc (1, sizeof *self);
+	return self;
+}
+
+static void
+channel_user_destroy (void *p)
+{
+	struct channel_user *self = p;
+	user_unref (self->user);
+	free (self);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+// We keep references to channels in their users and buffers,
+// as well as in the name lookup table.
+
+struct channel
+{
+	size_t ref_count;                   ///< Reference count
+
+	// TODO: eventually a reference to the server
+
+	char *name;                         ///< Channel name
+	char *mode;                         ///< Channel mode
+	char *topic;                        ///< Channel topic
+
+	struct channel_user *users;         ///< Channel users
+};
+
+static struct channel *
+channel_new (void)
+{
+	struct channel *self = xcalloc (1, sizeof *self);
+	self->ref_count = 1;
+	return self;
+}
+
+static void
+channel_destroy (void *p)
+{
+	struct channel *self = p;
+	free (self->name);
+	free (self->mode);
+	free (self->topic);
+	LIST_FOR_EACH (struct channel_user, iter, self->users)
+		channel_user_destroy (iter);
+	free (self);
+}
+
+static struct channel *
+channel_ref (struct channel *self)
+{
+	self->ref_count++;
+	return self;
+}
+
+static void
+channel_unref (void *p)
+{
+	struct channel *self = p;
+	if (!--self->ref_count)
+		channel_destroy (self);
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
 enum buffer_line_flags
 {
 	BUFFER_LINE_HIGHLIGHT   = 1 << 0    ///< The user was highlighted by this
@@ -202,20 +338,18 @@ struct buffer
 
 	unsigned unseen_messages_count;     ///< # messages since last visited
 
-	// Channel information:
+	// Origin information:
 
-	char *mode;                         ///< Channel mode
+	struct user *user;                  ///< Reference to user
-	char *topic;                        ///< Channel topic
+	struct channel *channel;            ///< Reference to channel
-	struct str_map nicks;               ///< Maps nicks to "nick_info"
+
+	// TODO: eventually a reference to the server for server buffers
 };
 
 static struct buffer *
 buffer_new (void)
 {
 	struct buffer *self = xcalloc (1, sizeof *self);
-	str_map_init (&self->nicks);
-	self->nicks.key_xfrm = irc_strxfrm;
-	self->nicks.free = nick_info_destroy;
 	return self;
 }
 
@@ -225,9 +359,12 @@ buffer_destroy (struct buffer *self)
 	free (self->name);
 	// Can't really free "history" here
 	free (self->saved_line);
-	free (self->mode);
+	LIST_FOR_EACH (struct buffer_line, iter, self->lines)
-	free (self->topic);
+		buffer_line_destroy (iter);
-	str_map_free (&self->nicks);
+	if (self->user)
+		user_unref (self->user);
+	if (self->channel)
+		channel_unref (self->channel);
 	free (self);
 }
 
@@ -260,7 +397,23 @@ struct app_context
 	SSL_CTX *ssl_ctx;                   ///< SSL context
 	SSL *ssl;                           ///< SSL connection
 
-	// TODO: channels?
+	// TODO: an output queue to prevent excess floods (this will be needed
+	//   especially for away status polling)
+
+	// XXX: there can be buffers for non-existent users
+	// TODO: user buffers rename on nick changes
+	// TODO: move entries in "irc_buffer_map" and "irc_users" when that happens
+	// TODO: user buffers may merge when an existing user renames to match
+	//   the name of a buffer for a non-existent user
+	// TODO: initialize key_strxfrm according to server properties;
+	//   note that collisions may arise on reconnecting
+	// TODO: when disconnected, get rid of all users everywhere;
+	//   maybe also broadcast all buffers about the disconnection event
+	// TODO: when getting connected again, rejoin all current channels
+
+	struct str_map irc_users;           ///< IRC user data
+	struct str_map irc_channels;        ///< IRC channel data
+	struct str_map irc_buffer_map;      ///< Maps IRC identifiers to buffers
 
 	// TODO: initialize and update these two values
 	// TODO: probably issue a USERHOST message for ourselves after connecting
@@ -288,6 +441,7 @@ struct app_context
 	struct buffer *buffers_tail;        ///< The tail of our buffers
 
 	// XXX: when we go multiserver, there will be collisions
+	// TODO: make buffer names unique like weechat does
 	struct str_map buffers_by_name;     ///< Excludes GLOBAL and SERVER
 
 	struct buffer *global_buffer;       ///< The global buffer
@@ -328,13 +482,22 @@ app_context_init (struct app_context *self)
 	str_init (&self->read_buffer);
 	self->irc_ready = false;
 
+	str_map_init (&self->irc_users);
+	self->irc_users.free = user_unref;
+	self->irc_users.key_xfrm = irc_strxfrm;
+	str_map_init (&self->irc_channels);
+	self->irc_channels.free = channel_unref;
+	self->irc_channels.key_xfrm = irc_strxfrm;
+	str_map_init (&self->irc_buffer_map);
+	self->irc_buffer_map.key_xfrm = irc_strxfrm;
+
+	poller_init (&self->poller);
+
 	str_map_init (&self->buffers_by_name);
 	self->buffers_by_name.key_xfrm = irc_strxfrm;
 
 	self->last_displayed_msg_time = time (NULL);
 
-	poller_init (&self->poller);
-
 	char *encoding = nl_langinfo (CODESET);
 #ifdef __linux__
 	encoding = xstrdup_printf ("%s//TRANSLIT", encoding);
@@ -370,15 +533,19 @@ app_context_free (struct app_context *self)
 	if (self->ssl_ctx)
 		SSL_CTX_free (self->ssl_ctx);
 
+	str_map_free (&self->irc_users);
+	str_map_free (&self->irc_channels);
+	str_map_free (&self->irc_buffer_map);
+
 	free (self->irc_nickname);
 	free (self->irc_user_mode);
 
+	poller_free (&self->poller);
+
 	LIST_FOR_EACH (struct buffer, iter, self->buffers)
 		buffer_destroy (iter);
 	str_map_free (&self->buffers_by_name);
 
-	poller_free (&self->poller);
-
 	iconv_close (self->latin1_to_utf8);
 	iconv_close (self->term_from_utf8);
 	iconv_close (self->term_to_utf8);
@@ -1373,8 +1540,8 @@ make_prompt (struct app_context *ctx, struct str *output)
 
 	str_append_printf (output, "%d:%s",
 		buffer_get_index (ctx, buffer), buffer->name);
-	if (buffer->type == BUFFER_CHANNEL && *buffer->mode)
+	if (buffer->type == BUFFER_CHANNEL && *buffer->channel->mode)
-		str_append_printf (output, "(%s)", buffer->mode);
+		str_append_printf (output, "(%s)", buffer->channel->mode);
 
 	if (buffer != ctx->global_buffer)
 	{