WIPscratch/ts-linecol

1 files changed, 30 insertions, 0 deletions

diff --git a/src/buffer.h b/src/buffer.h
index 5c0a6ab3118..9479b141424 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -220,6 +220,23 @@ extern ptrdiff_t advance_to_char_boundary (ptrdiff_t byte_pos);
 
 /* Define the actual buffer data structures.  */
 
+/* This data structure stores the cache of a position and its line and
+   column number.  The column number is counted in bytes.  The line
+   number and column number don't consider narrowing.  */
+struct ts_linecol
+{
+  /* A position in the buffer.  */
+  ptrdiff_t pos;
+  /* The byte position of POS.  */
+  ptrdiff_t byte_pos;
+  /* The line number of this position.  */
+  ptrdiff_t line;
+  /* The column number (in bytes) of this position.  Unlike Emacs'
+     convention, this is 0-based (because tree-sitter column is
+     0-based).  Simply the byte offset from BOL (or BOB).  */
+  ptrdiff_t col;
+};
+
 /* This data structure describes the actual text contents of a buffer.
    It is shared between indirect buffers and their base buffer.  */
 
@@ -700,6 +717,19 @@ struct buffer
   /* The interval tree containing this buffer's overlays. */
   struct itree_tree *overlays;
 
+  /* Right now only tree-sitter makes use of this, so I don't want
+     non-tree-sitter build to pay for it.  If something else can make
+     use of this, we can remove the gate.  */
+#ifdef HAVE_TREE_SITTER
+  /* Cache of line and column number of a position.  The position cached
+     is usually near point.  Tree-sitter uses this cache to calculate
+     line and column of the beginning and end of buffer edits.  This
+     cache is refreshed in buffer edit functions, so it's always
+     up-to-date.  Usually, the newly calculated position and line/column
+     are saved to this field.  Initialized to position 1.  */
+  struct ts_linecol ts_linecol_cache;
+#endif
+
   /* Changes in the buffer are recorded here for undo, and t means
      don't record anything.  This information belongs to the base
      buffer of an indirect buffer.  But we can't store it in the