organize buffer ring as a tail-q (double-linked list with tail pointer)

 * new buffers are added at the list tail
 * when closing a buffer, the next one is selected or the previous one if it is the tail
 * the ring may be traversed in reverse order
 * undoing a buffer close (Ring::UndoTokenEdit) could be cleaned up to only use standard macros (is slightly less efficient though)

2 files changed, 51 insertions, 36 deletions

diff --git a/qbuffers.cpp b/qbuffers.cpp
index 1ee9139..7269699 100644
--- a/qbuffers.cpp
+++ b/qbuffers.cpp
@@ -364,6 +364,14 @@ QRegisters::hook(Hook type)
 	globals["0"]->execute();
 }
 
+void
+Buffer::UndoTokenClose::run(void)
+{
+	ring.close(buffer);
+	/* NOTE: the buffer is NOT deleted on Token destruction */
+	delete buffer;
+}
+
 bool
 Buffer::load(const gchar *filename)
 {
@@ -396,29 +404,16 @@ Buffer::load(const gchar *filename)
 }
 
 void
-Buffer::close(void)
-{
-	LIST_REMOVE(this, buffers);
-
-	if (filename)
-		interface.msg(Interface::MSG_INFO,
-			      "Removed file \"%s\" from the ring",
-			      filename);
-	else
-		interface.msg(Interface::MSG_INFO,
-			      "Removed unnamed file from the ring.");
-}
-
-void
 Ring::UndoTokenEdit::run(void)
 {
 	/*
 	 * assumes that buffer still has correct prev/next
 	 * pointers
 	 */
-	*buffer->buffers.le_prev = buffer;
 	if (buffer->next())
-		buffer->next()->buffers.le_prev = &buffer->next();
+		TAILQ_INSERT_BEFORE(buffer->next(), buffer, buffers);
+	else
+		TAILQ_INSERT_TAIL(&ring->head, buffer, buffers);
 
 	ring->current = buffer;
 	buffer->edit();
@@ -431,7 +426,7 @@ Ring::find(const gchar *filename)
 	gchar *resolved = get_absolute_path(filename);
 	Buffer *cur;
 
-	LIST_FOREACH(cur, &head, buffers)
+	TAILQ_FOREACH(cur, &head, buffers)
 		if (!g_strcmp0(cur->filename, resolved))
 			break;
 
@@ -444,7 +439,7 @@ Ring::find(gint64 id)
 {
 	Buffer *cur;
 
-	LIST_FOREACH(cur, &head, buffers)
+	TAILQ_FOREACH(cur, &head, buffers)
 		if (!--id)
 			break;
 
@@ -468,7 +463,7 @@ Ring::is_any_dirty(void)
 {
 	Buffer *cur;
 
-	LIST_FOREACH(cur, &head, buffers)
+	TAILQ_FOREACH(cur, &head, buffers)
 		if (cur->dirty)
 			return true;
 
@@ -509,7 +504,7 @@ Ring::edit(const gchar *filename)
 		QRegisters::hook(QRegisters::HOOK_EDIT);
 	} else {
 		buffer = new Buffer();
-		LIST_INSERT_HEAD(&head, buffer, buffers);
+		TAILQ_INSERT_TAIL(&head, buffer, buffers);
 
 		current = buffer;
 		undo_close();
@@ -669,13 +664,27 @@ Ring::save(const gchar *filename)
 }
 
 void
+Ring::close(Buffer *buffer)
+{
+	TAILQ_REMOVE(&head, buffer, buffers);
+
+	if (buffer->filename)
+		interface.msg(Interface::MSG_INFO,
+			      "Removed file \"%s\" from the ring",
+			      buffer->filename);
+	else
+		interface.msg(Interface::MSG_INFO,
+			      "Removed unnamed file from the ring.");
+}
+
+void
 Ring::close(void)
 {
 	Buffer *buffer = current;
 
 	buffer->dot = interface.ssm(SCI_GETCURRENTPOS);
-	buffer->close();
-	current = buffer->next() ? : first();
+	close(buffer);
+	current = buffer->next() ? : buffer->prev();
 	/* transfer responsibility to UndoToken object */
 	undo.push(new UndoTokenEdit(this, buffer));
 
@@ -693,7 +702,7 @@ Ring::~Ring()
 {
 	Buffer *buffer, *next;
 
-	LIST_FOREACH_SAFE(buffer, &head, buffers, next)
+	TAILQ_FOREACH_SAFE(buffer, &head, buffers, next)
 		delete buffer;
 }
 
diff --git a/qbuffers.h b/qbuffers.h
index 0fd588d..05ec388 100644
--- a/qbuffers.h
+++ b/qbuffers.h
@@ -263,17 +263,11 @@ class Buffer {
 		UndoTokenClose(Buffer *_buffer)
 			      : UndoToken(), buffer(_buffer) {}
 
-		void
-		run(void)
-		{
-			buffer->close();
-			/* NOTE: the buffer is NOT deleted on Token destruction */
-			delete buffer;
-		}
+		void run(void);
 	};
 
 public:
-	LIST_ENTRY(Buffer) buffers;
+	TAILQ_ENTRY(Buffer) buffers;
 
 	gchar *filename;
 	gint dot;
@@ -300,7 +294,14 @@ public:
 	inline Buffer *&
 	next(void)
 	{
-		return LIST_NEXT(this, buffers);
+		return TAILQ_NEXT(this, buffers);
+	}
+	inline Buffer *&
+	prev(void)
+	{
+		TAILQ_HEAD(Head, Buffer);
+
+		return TAILQ_PREV(this, Head, buffers);
 	}
 
 	inline void
@@ -329,7 +330,6 @@ public:
 
 	bool load(const gchar *filename);
 
-	void close(void);
 	inline void
 	undo_close(void)
 	{
@@ -376,21 +376,26 @@ extern class Ring {
 		}
 	};
 
-	LIST_HEAD(Head, Buffer) head;
+	TAILQ_HEAD(Head, Buffer) head;
 
 public:
 	Buffer *current;
 
 	Ring() : current(NULL)
 	{
-		LIST_INIT(&head);
+		TAILQ_INIT(&head);
 	}
 	~Ring();
 
 	inline Buffer *
 	first(void)
 	{
-		return LIST_FIRST(&head);
+		return TAILQ_FIRST(&head);
+	}
+	inline Buffer *
+	last(void)
+	{
+		return TAILQ_LAST(&head, Head);
 	}
 
 	Buffer *find(const gchar *filename);
@@ -411,6 +416,7 @@ public:
 
 	bool save(const gchar *filename);
 
+	void close(Buffer *buffer);
 	void close(void);
 	inline void
 	undo_close(void)