Implement buffer-widen-limits functionalityscratch/widen-limits

 `widen` now respects restrictions imposed by new variable
 `hard-widen-limits`

1 files changed, 17 insertions, 0 deletions

diff --git a/src/buffer.h b/src/buffer.h
index 87b7cee4413..4075bbf555c 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -59,6 +59,10 @@ INLINE_HEADER_BEGIN
 #define Z (current_buffer->text->z)
 #define Z_BYTE (current_buffer->text->z_byte)
 
+/* Positions that take into account widen limits.  */
+#define BEGWL (BUF_BEGWL (current_buffer))
+#define ZWL (BUF_ZWL(current_buffer))
+
 /* Macros for the addresses of places in the buffer.  */
 
 /* Address of beginning of buffer.  */
@@ -128,6 +132,15 @@ INLINE_HEADER_BEGIN
     : NILP (BVAR (buf, begv_marker)) ? buf->begv_byte   \
     : marker_byte_position (BVAR (buf, begv_marker)))
 
+/* Hard positions in buffer. */
+#define BUF_BEGWL(buf)                                          \
+  ((NILP (BVAR (buf, widen_limits))) ?  BUF_BEG (buf)    \
+   : XINT( XCAR (BVAR (buf, widen_limits))))
+
+#define BUF_ZWL(buf)                                    \
+  ((NILP (BVAR (buf, widen_limits))) ?  BUF_Z (buf)      \
+   : XINT( XCDR (BVAR (buf, widen_limits))))
+
 /* Position of point in buffer.  */
 #define BUF_PT(buf)                                     \
    (buf == current_buffer ? PT                          \
@@ -150,6 +163,7 @@ INLINE_HEADER_BEGIN
     : NILP (BVAR (buf, zv_marker)) ? buf->zv_byte       \
     : marker_byte_position (BVAR (buf, zv_marker)))
 
+
 /* Position of gap in buffer.  */
 #define BUF_GPT(buf) ((buf)->text->gpt)
 #define BUF_GPT_BYTE(buf) ((buf)->text->gpt_byte)
@@ -748,6 +762,9 @@ struct buffer
      See `cursor-type' for other values.  */
   Lisp_Object cursor_in_non_selected_windows_;
 
+  /* Cons of hard widen limits */
+  Lisp_Object widen_limits_;
+
   /* No more Lisp_Object beyond this point.  Except undo_list,
      which is handled specially in Fgarbage_collect.  */