1 files changed, 52 insertions, 5 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index e27c85cd4f..9a5ffecad4 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -15,6 +15,7 @@
 #include "nvim/buffer.h"
 #include "nvim/charset.h"
 #include "nvim/cursor.h"
+#include "nvim/getchar.h"
 #include "nvim/memline.h"
 #include "nvim/memory.h"
 #include "nvim/misc1.h"
@@ -97,7 +98,7 @@ String buffer_get_line(Buffer buffer, Integer index, Error *err)
   return rv;
 }
 
-/// Activate updates from this buffer to the current channel.
+/// Activates buffer-update events on the channel.
 ///
 /// @param channel_id
 /// @param buffer Buffer handle, or 0 for current buffer
@@ -106,7 +107,7 @@ String buffer_get_line(Buffer buffer, Integer index, Error *err)
 ///        `nvim_buf_lines_event`. Otherwise, the first notification will be
 ///        a `nvim_buf_changedtick_event`
 /// @param  opts  Optional parameters. Reserved for future use.
-/// @param[out] err Details of an error that may have occurred
+/// @param[out] err Error details, if any
 /// @return False when updates couldn't be enabled because the buffer isn't
 ///         loaded or `opts` contained an invalid key; otherwise True.
 Boolean nvim_buf_attach(uint64_t channel_id,
@@ -129,12 +130,12 @@ Boolean nvim_buf_attach(uint64_t channel_id,
 
   return buf_updates_register(buf, channel_id, send_buffer);
 }
-//
-/// Deactivate updates from this buffer to the current channel.
+
+/// Deactivates buffer-update events on the channel.
 ///
 /// @param channel_id
 /// @param buffer Buffer handle, or 0 for current buffer
-/// @param[out] err Details of an error that may have occurred
+/// @param[out] err Error details, if any
 /// @return False when updates couldn't be disabled because the buffer
 ///         isn't loaded; otherwise True.
 Boolean nvim_buf_detach(uint64_t channel_id,
@@ -474,6 +475,7 @@ void nvim_buf_set_lines(uint64_t channel_id,
               false);
 
   changed_lines((linenr_T)start, 0, (linenr_T)end, (long)extra, true);
+  fix_cursor((linenr_T)start, (linenr_T)end, (linenr_T)extra);
 
 end:
   for (size_t i = 0; i < new_len; i++) {
@@ -575,6 +577,31 @@ ArrayOf(Dictionary) nvim_buf_get_keymap(Buffer buffer, String mode, Error *err)
   return keymap_array(mode, buf);
 }
 
+/// Sets a buffer-local |mapping| for the given mode.
+///
+/// @see |nvim_set_keymap()|
+///
+/// @param  buffer  Buffer handle, or 0 for current buffer
+void nvim_buf_set_keymap(Buffer buffer, String mode, String lhs, String rhs,
+                         Dictionary opts, Error *err)
+  FUNC_API_SINCE(6)
+{
+  modify_keymap(buffer, false, mode, lhs, rhs, opts, err);
+}
+
+/// Unmaps a buffer-local |mapping| for the given mode.
+///
+/// @see |nvim_del_keymap()|
+///
+/// @param  buffer  Buffer handle, or 0 for current buffer
+void nvim_buf_del_keymap(Buffer buffer, String mode, String lhs, Error *err)
+  FUNC_API_SINCE(6)
+{
+  String rhs = { .data = "", .size = 0 };
+  Dictionary opts = ARRAY_DICT_INIT;
+  modify_keymap(buffer, true, mode, lhs, rhs, opts, err);
+}
+
 /// Gets a map of buffer-local |user-commands|.
 ///
 /// @param  buffer  Buffer handle, or 0 for current buffer
@@ -1106,6 +1133,26 @@ free_exit:
   return 0;
 }
 
+// Check if deleting lines made the cursor position invalid.
+// Changed lines from `lo` to `hi`; added `extra` lines (negative if deleted).
+static void fix_cursor(linenr_T lo, linenr_T hi, linenr_T extra)
+{
+  if (curwin->w_cursor.lnum >= lo) {
+    // Adjust cursor position if it's in/after the changed lines.
+    if (curwin->w_cursor.lnum >= hi) {
+      curwin->w_cursor.lnum += extra;
+      check_cursor_col();
+    } else if (extra < 0) {
+      curwin->w_cursor.lnum = lo;
+      check_cursor();
+    } else {
+      check_cursor_col();
+    }
+    changed_cline_bef_curs();
+  }
+  invalidate_botline();
+}
+
 // Normalizes 0-based indexes to buffer line numbers
 static int64_t normalize_index(buf_T *buf, int64_t index, bool *oob)
 {