API: Implement buffer_get_mark

src/api/buffer.c

@@ -321,9 +321,41 @@ void buffer_insert(Buffer buffer, int64_t index, StringArray lines, Error *err)
   buffer_set_slice(buffer, index, index, false, true, lines, err);
 }
 
-Position buffer_mark(Buffer buffer, String name, Error *err)
+Position buffer_get_mark(Buffer buffer, String name, Error *err)
 {
-  abort();
+  Position rv;
+  buf_T *buf = find_buffer(buffer, err);
+
+  if (!buf) {
+    return rv;
+  }
+
+  if (name.size != 0) {
+    set_api_error("mark name must be a single character", err);
+    return rv;
+  }
+
+  pos_T *posp;
+  buf_T *savebuf;
+  char mark = *name.data;
+
+  try_start();
+  switch_buffer(&savebuf, buf);
+  posp = getmark(mark, false);
+  restore_buffer(savebuf);
+
+  if (try_end(err)) {
+    return rv;
+  }
+
+  if (posp == NULL) {
+    set_api_error("invalid mark name", err);
+    return rv;
+  }
+
+  rv.row = posp->lnum;
+  rv.col = posp->col;
+  return rv;
 }
 
 static void switch_to_win_for_buf(buf_T *buf,

src/api/buffer.h

@@ -133,14 +133,13 @@ bool buffer_is_valid(Buffer buffer);
 /// @param[out] err Details of an error that may have occurred
 void buffer_insert(Buffer buffer, int64_t index, StringArray lines, Error *err);
 
-/// Creates a mark in the buffer and returns a tuple(row, col) representing 
+/// Return a tuple (row,col) representing the position of the named mark
-/// the position of the named mark
 ///
 /// @param buffer The buffer handle
 /// @param name The mark's name
 /// @param[out] err Details of an error that may have occurred
 /// @return The (row, col) tuple
-Position buffer_mark(Buffer buffer, String name, Error *err);
+Position buffer_get_mark(Buffer buffer, String name, Error *err);
 
 #endif // NEOVIM_API_BUFFER_H