Revert "rfc: use extmarks for highlighting and carets (#2099)" (#2138)

This reverts commit 8d13f4ca8a.

lua/telescope/pickers.lua

@@ -262,6 +262,43 @@ function Picker:clear_extra_rows(results_bufnr)
   log.trace("Clearing:", worst_line)
 end
 
+--- Highlight the entry corresponding to the given row
+---@param results_bufnr number: the buffer number of the results buffer
+---@param prompt table: table with information about the prompt buffer
+---@param display string: the text corresponding to the given row
+---@param row number: the number of the chosen row
+function Picker:highlight_one_row(results_bufnr, prompt, display, row)
+  if not self.sorter.highlighter then
+    return
+  end
+
+  local highlights = self.sorter:highlighter(prompt, display)
+
+  if highlights then
+    for _, hl in ipairs(highlights) do
+      local highlight, start, finish
+      if type(hl) == "table" then
+        highlight = hl.highlight or "TelescopeMatching"
+        start = hl.start
+        finish = hl.finish or hl.start
+      elseif type(hl) == "number" then
+        highlight = "TelescopeMatching"
+        start = hl
+        finish = hl
+      else
+        error "Invalid higlighter fn"
+      end
+
+      self:_increment "highlights"
+
+      vim.api.nvim_buf_add_highlight(results_bufnr, ns_telescope_matching, highlight, row, start - 1, finish)
+    end
+  end
+
+  local entry = self.manager:get_entry(self:get_index(row))
+  self.highlighter:hi_multiselect(row, self:is_multi_selected(entry))
+end
+
 --- Check if the given row number can be selected
 ---@param row number: the number of the chosen row in the results buffer
 ---@return boolean
@@ -762,6 +799,7 @@ function Picker:add_selection(row)
   local entry = self.manager:get_entry(self:get_index(row))
   self._multi:add(entry)
 
+  self:update_prefix(entry, row)
   self:get_status_updater(self.prompt_win, self.prompt_bufnr)()
   self.highlighter:hi_multiselect(row, true)
 end
@@ -772,6 +810,7 @@ function Picker:remove_selection(row)
   local entry = self.manager:get_entry(self:get_index(row))
   self._multi:drop(entry)
 
+  self:update_prefix(entry, row)
   self:get_status_updater(self.prompt_win, self.prompt_bufnr)()
   self.highlighter:hi_multiselect(row, false)
 end
@@ -800,6 +839,7 @@ function Picker:toggle_selection(row)
   end
   self._multi:toggle(entry)
 
+  self:update_prefix(entry, row)
   self:get_status_updater(self.prompt_win, self.prompt_bufnr)()
   self.highlighter:hi_multiselect(row, self._multi:is_selected(entry))
 end
@@ -947,6 +987,7 @@ function Picker:set_selection(row)
       self._selection_entry = entry
 
       if old_row >= 0 then
+        self:update_prefix(old_entry, old_row)
         self.highlighter:hi_multiselect(old_row, self:is_multi_selected(old_entry))
       end
     else
@@ -1005,7 +1046,25 @@ function Picker:update_prefix(entry, row)
     return t
   end
 
-  return prefix(entry == self._selection_entry, self:is_multi_selected(entry))
+  local line = vim.api.nvim_buf_get_lines(self.results_bufnr, row, row + 1, false)[1]
+  if not line then
+    log.trace(string.format("no line found at row %d in buffer %d", row, self.results_bufnr))
+    return
+  end
+
+  local old_caret = string.sub(line, 0, #prefix(true)) == prefix(true) and prefix(true)
+    or string.sub(line, 0, #prefix(true, true)) == prefix(true, true) and prefix(true, true)
+    or string.sub(line, 0, #prefix(false)) == prefix(false) and prefix(false)
+    or string.sub(line, 0, #prefix(false, true)) == prefix(false, true) and prefix(false, true)
+  if old_caret == false then
+    log.warn(string.format("can't identify old caret in line: %s", line))
+    return
+  end
+
+  local pre = prefix(entry == self._selection_entry, self:is_multi_selected(entry))
+  -- Only change the first couple characters, nvim_buf_set_text leaves the existing highlights
+  a.nvim_buf_set_text(self.results_bufnr, row, 0, row, #old_caret, { pre })
+  return pre
 end
 
 --- Refresh the previewer based on the current `status` of the picker
@@ -1105,7 +1164,8 @@ function Picker:entry_adder(index, entry, _, insert)
     if display_highlights then
       self.highlighter:hi_display(row, prefix, display_highlights)
     end
-    self.highlighter:hi_sorter(row, self:_get_prompt(), display)
+    self:update_prefix(entry, row)
+    self:highlight_one_row(self.results_bufnr, self:_get_prompt(), display, row)
   end
 
   if not set_ok then
@@ -1311,6 +1371,7 @@ function Picker:_do_selection(prompt)
       local old_entry, old_row = self._selection_entry, self._selection_row
       self:reset_selection() -- required to reset selection before updating prefix
       if old_row >= 0 then
+        self:update_prefix(old_entry, old_row)
         self.highlighter:hi_multiselect(old_row, self:is_multi_selected(old_entry))
       end
     end