[vte/vte-0-36] ring, stream: Refactor the interface between the ring and the stream

[Christian Persch <chpe src gnome org>]

commit 7a201c651251b483a026eae60c1f48cc27da7abe
Author: Egmont Koblinger <egmont gmail com>
Date:   Wed Oct 23 00:22:42 2013 +0200

    ring,stream: Refactor the interface between the ring and the stream
    
    Refactor and simplify the interface between ring and vte-stream; this is
    required for the forthcoming rewrapping feature. Paging is now a concept
    private to vte-stream. Instead of telling when to turn page, the ring now
    advances the tail of the streams, and vte-stream does paging on its own
    based on this information.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=336238#c74

 src/ring.c           |   36 ++++++++++++------------------------
 src/ring.h           |    1 -
 src/vtestream-base.h |   14 ++++++--------
 src/vtestream-file.h |   18 ++++++++++--------
 src/vtestream.h      |    9 ++-------
 5 files changed, 30 insertions(+), 48 deletions(-)
---
diff --git a/src/ring.c b/src/ring.c
index aa4e364..4caf2d4 100644
--- a/src/ring.c
+++ b/src/ring.c
@@ -124,8 +124,8 @@ _vte_ring_freeze_row (VteRing *ring, gulong position, const VteRowData *row)
 
        _vte_debug_print (VTE_DEBUG_RING, "Freezing row %lu.\n", position);
 
-       record.text_start_offset = _vte_stream_head (ring->text_stream, 0);
-       record.attr_start_offset = _vte_stream_head (ring->attr_stream, 0);
+       record.text_start_offset = _vte_stream_head (ring->text_stream);
+       record.attr_start_offset = _vte_stream_head (ring->attr_stream);
 
        g_string_set_size (buffer, 0);
        for (i = 0, cell = row->cells; i < row->len; i++, cell++) {
@@ -199,11 +199,11 @@ _vte_ring_thaw_row (VteRing *ring, gulong position, VteRowData *row, gboolean do
 
        if (!_vte_ring_read_row_record (ring, &records[0], position))
                return;
-       if ((position + 1) * sizeof (records[0]) < _vte_stream_head (ring->row_stream, 0)) {
+       if ((position + 1) * sizeof (records[0]) < _vte_stream_head (ring->row_stream)) {
                if (!_vte_ring_read_row_record (ring, &records[1], position + 1))
                        return;
        } else
-               records[1].text_start_offset = _vte_stream_head (ring->text_stream, 0);
+               records[1].text_start_offset = _vte_stream_head (ring->text_stream);
 
        g_string_set_size (buffer, records[1].text_start_offset - records[0].text_start_offset);
        if (!_vte_stream_read (ring->text_stream, records[0].text_start_offset, buffer->str, buffer->len))
@@ -301,24 +301,8 @@ _vte_ring_reset_streams (VteRing *ring, gulong position)
 
        ring->last_attr_text_start_offset = 0;
        ring->last_attr.i = basic_cell.i.attr;
-
-       ring->last_page = position;
-}
-
-static void
-_vte_ring_new_page (VteRing *ring)
-{
-       _vte_debug_print (VTE_DEBUG_RING, "Starting new stream page at %lu.\n", ring->writable);
-
-       _vte_stream_new_page (ring->attr_stream);
-       _vte_stream_new_page (ring->text_stream);
-       _vte_stream_new_page (ring->row_stream);
-
-       ring->last_page = ring->writable;
 }
 
-
-
 static inline VteRowData *
 _vte_ring_writable_index (VteRing *ring, gulong position)
 {
@@ -365,9 +349,6 @@ _vte_ring_freeze_one_row (VteRing *ring)
        _vte_ring_freeze_row (ring, ring->writable, row);
 
        ring->writable++;
-
-       if (G_UNLIKELY (ring->writable == ring->last_page || ring->writable - ring->last_page >= ring->max))
-               _vte_ring_new_page (ring);
 }
 
 static void
@@ -395,6 +376,13 @@ _vte_ring_discard_one_row (VteRing *ring)
        ring->start++;
        if (G_UNLIKELY (ring->start == ring->writable)) {
                _vte_ring_reset_streams (ring, 0);
+       } else {
+               VteRowRecord record;
+               _vte_stream_advance_tail (ring->row_stream, ring->start * sizeof (record));
+               if (G_LIKELY (_vte_ring_read_row_record (ring, &record, ring->start))) {
+                       _vte_stream_advance_tail (ring->text_stream, record.text_start_offset);
+                       _vte_stream_advance_tail (ring->attr_stream, record.attr_start_offset);
+               }
        }
        if (ring->start > ring->writable)
                ring->writable = ring->start;
@@ -665,7 +653,7 @@ _vte_ring_write_contents (VteRing *ring,
                if (_vte_ring_read_row_record (ring, &record, ring->start))
                {
                        gsize start_offset = record.text_start_offset;
-                       gsize end_offset = _vte_stream_head (ring->text_stream, 0);
+                       gsize end_offset = _vte_stream_head (ring->text_stream);
                        char buf[4096];
                        while (start_offset < end_offset)
                        {
diff --git a/src/ring.h b/src/ring.h
index d4cab96..bd98e4a 100644
--- a/src/ring.h
+++ b/src/ring.h
@@ -53,7 +53,6 @@ struct _VteRing {
        VteRowData *array;
 
        /* Storage */
-       gulong last_page;
        VteStream *attr_stream, *text_stream, *row_stream;
        gsize last_attr_text_start_offset;
        VteIntCellAttr last_attr;
diff --git a/src/vtestream-base.h b/src/vtestream-base.h
index 2732b20..f40fd6a 100644
--- a/src/vtestream-base.h
+++ b/src/vtestream-base.h
@@ -36,8 +36,8 @@ typedef struct _VteStreamClass {
        void (*append) (VteStream *stream, const char *data, gsize len);
        gboolean (*read) (VteStream *stream, gsize offset, char *data, gsize len);
        void (*truncate) (VteStream *stream, gsize offset);
-       void (*new_page) (VteStream *stream);
-       gsize (*head) (VteStream *stream, guint index);
+       void (*advance_tail) (VteStream *stream, gsize offset);
+       gsize (*head) (VteStream *stream);
 } VteStreamClass;
 
 static GType _vte_stream_get_type (void);
@@ -81,15 +81,13 @@ _vte_stream_truncate (VteStream *stream, gsize offset)
 }
 
 void
-_vte_stream_new_page (VteStream *stream)
+_vte_stream_advance_tail (VteStream *stream, gsize offset)
 {
-       VTE_STREAM_GET_CLASS (stream)->new_page (stream);
+       VTE_STREAM_GET_CLASS (stream)->advance_tail (stream, offset);
 }
 
 gsize
-_vte_stream_head (VteStream *stream, guint index)
+_vte_stream_head (VteStream *stream)
 {
-       g_assert (index < 3);
-
-       return VTE_STREAM_GET_CLASS (stream)->head (stream, index);
+       return VTE_STREAM_GET_CLASS (stream)->head (stream);
 }
diff --git a/src/vtestream-file.h b/src/vtestream-file.h
index e9d8d77..06de79d 100644
--- a/src/vtestream-file.h
+++ b/src/vtestream-file.h
@@ -460,22 +460,24 @@ _vte_file_stream_truncate (VteStream *astream, gsize offset)
 }
 
 static void
-_vte_file_stream_new_page (VteStream *astream)
+_vte_file_stream_advance_tail (VteStream *astream, gsize offset)
 {
        VteFileStream *stream = (VteFileStream *) astream;
 
-       stream->offset[1] = stream->offset[0];
-       stream->offset[0] = stream->head;
-       _vte_file_stream_swap_fds (stream);
-       _file_reset (&stream->file[0]);
+       if (offset >= stream->offset[0]) {
+               stream->offset[1] = stream->offset[0];
+               stream->offset[0] = stream->head;
+               _vte_file_stream_swap_fds (stream);
+               _file_reset (&stream->file[0]);
+       }
 }
 
 static gsize
-_vte_file_stream_head (VteStream *astream, guint _index)
+_vte_file_stream_head (VteStream *astream)
 {
        VteFileStream *stream = (VteFileStream *) astream;
 
-       return _index == 0 ? stream->head : stream->offset[_index - 1];
+       return stream->head;
 }
 
 static void
@@ -489,6 +491,6 @@ _vte_file_stream_class_init (VteFileStreamClass *klass)
        klass->append = _vte_file_stream_append;
        klass->read = _vte_file_stream_read;
        klass->truncate = _vte_file_stream_truncate;
-       klass->new_page = _vte_file_stream_new_page;
+       klass->advance_tail = _vte_file_stream_advance_tail;
        klass->head = _vte_file_stream_head;
 }
diff --git a/src/vtestream.h b/src/vtestream.h
index e968d42..ada51e9 100644
--- a/src/vtestream.h
+++ b/src/vtestream.h
@@ -32,13 +32,8 @@ void _vte_stream_reset (VteStream *stream, gsize offset);
 void _vte_stream_append (VteStream *stream, const char *data, gsize len);
 gboolean _vte_stream_read (VteStream *stream, gsize offset, char *data, gsize len);
 void _vte_stream_truncate (VteStream *stream, gsize offset);
-void _vte_stream_new_page (VteStream *stream);
-/* The stream has two pages at each time.  This function returns three positions:
- * - index == 0 -> position of writing head,
- * - index == 1 -> start of current page,
- * - index == 2 -> start of previous page (ie. last offset available in stream)
- */
-gsize _vte_stream_head (VteStream *stream, guint index);
+void _vte_stream_advance_tail (VteStream *stream, gsize offset);
+gsize _vte_stream_head (VteStream *stream);
 
 /* Various streams */