TEMP: shadowsplice "plugin" to show incorrect or too low-resolution u…

…pdates

shadowsplice.lua

@@ -0,0 +1,104 @@
+local a = vim.api
+_G.a = vim.api
+local luadev = require'luadev'
+local ssp = _G.ssp or {}
+_G.ssp = ssp
+
+ssp.ns = a.nvim_create_namespace("ssp")
+
+function ssp.start(bufnr)
+  if bufnr == nil or bufnr == 0 then
+    bufnr = a.nvim_get_current_buf()
+  end
+  ssp.bufnr = bufnr
+  ssp.sched = false
+  ssp.reset()
+  a.nvim_buf_attach(bufnr, false, {on_bytes=function(...)
+    ssp.on_bytes(...)
+  end})
+end
+
+function ssp.reset()
+  local text = a.nvim_buf_get_lines(ssp.bufnr, 0, -1, true)
+  local bytes = table.concat(text, '\n') .. '\n'
+  ssp.shadow = bytes
+  ssp.dirty = false
+  a.nvim_buf_clear_namespace(ssp.bufnr, ssp.ns, 0, -1)
+end
+
+function ssp.on_bytes(_, buf, tick, start_row, start_col, start_byte, old_row, old_col, old_byte, new_row, new_col, new_byte)
+  local before = string.sub(ssp.shadow, 1, start_byte)
+  -- assume no text will contain 0xff bytes (invalid UTF-8)
+  -- so we can use it as marker for unknown bytes
+  local unknown = string.rep('\255', new_byte)
+  local after = string.sub(ssp.shadow, start_byte + old_byte + 1)
+  ssp.shadow = before .. unknown .. after
+  if not ssp.sched then
+    vim.schedule(ssp.show)
+    ssp.sched = true
+  end
+
+  vim.schedule(function()
+    luadev.print(vim.inspect{start_row, start_col, start_byte, old_row, old_col, old_byte, new_row, new_col, new_byte})
+  end)
+end
+
+function ssp.sync()
+  local text = a.nvim_buf_get_lines(ssp.bufnr, 0, -1, true)
+  local bytes = table.concat(text, '\n') .. '\n'
+  for i = 1, string.len(ssp.shadow) do
+    local shadowbyte = string.sub(ssp.shadow, i, i)
+    if shadowbyte ~= '\255' then
+      if string.sub(bytes, i, i) ~= shadowbyte then
+        error(i)
+      end
+    end
+  end
+end
+
+function ssp.show()
+  ssp.sched = false
+  a.nvim_buf_clear_namespace(ssp.bufnr, ssp.ns, 0, -1)
+  local text = a.nvim_buf_get_lines(ssp.bufnr, 0, -1, true)
+  local bytes = table.concat(text, '\n') .. '\n'
+  local line, lastpos = 0, 0
+  for i = 1, string.len(ssp.shadow) do
+    local textbyte = string.sub(bytes, i, i)
+    if textbyte == '\n' then
+      line = line + 1
+      lastpos = i
+    end
+    local shadowbyte = string.sub(ssp.shadow, i, i)
+    pcall(function()
+      if shadowbyte ~= '\255' then
+        if textbyte ~= shadowbyte then
+            a.nvim_buf_set_virtual_text(ssp.bufnr, ssp.ns, line, {{"ERR", "ErrorMsg"}}, {})
+            a.nvim_buf_add_highlight(ssp.bufnr, ssp.ns, "ErrorMsg", line, i-lastpos-1, i-lastpos)
+        end
+      else
+        if i - lastpos == 0 then
+          a.nvim_buf_set_virtual_text(ssp.bufnr, ssp.ns, line-1, {{" ", "RedrawDebugComposed"}}, {})
+        else
+          a.nvim_buf_add_highlight(ssp.bufnr, ssp.ns, "StatusLine", line, i-lastpos-1, i-lastpos)
+        end
+      end
+    end)
+  end
+end
+
+ssp.reset()
+
+ra = [[
+ssp.start()
+ssp.reset()
+eee
+eee
+eeee
+ssp.show()
+ssp.sync()
+bx
+yb
+  vim.schedule(function() luadev.print(vim.inspect(yarg)) end)
+  -- args are "nvim_buf_lines_event", 1, 85, 8, 8, { "" }, false
+bb
+]]