Scite Merge On Change

wiki

Useful for saving yourself from deleting recent changes if you have the same file opened multiple times, or when updating a repository when its files are already open.

The Unix version uses stat, diff, and diff3 to detect and merge changes.

I couldn't find an equivalent of stat in Windows, so the Windows version uses md5sum to detect changes instead; you'll need Windows ports of md5sum, diff, and diff3 [GnuWin32], and their bin directory needs to be in your PATH environment variable so that the script can execute them.

Source

-- Will be replaced by a function for escaping shell strings, once we know know how

local shellString = nil



-- Will be replaced by a function for generating a string for a file that will change when that file changes.

local fileState = nil



local shell = os.getenv("SHELL")

if shell then shell = shell:match("([^\\/]+)$") end



if not shell then

  if not os.getenv("WinDir") then

    error("$SHELL is undefined, and this doesn't seem to be Windows.")

  end

  

  -- Assume the shell is cmd

  local function shellEscapeCharacter(c)

    -- Escape character doesn't work in quoted strings, and spaces can't be escaped? Tragic!

    -- So I quote the spaces and don't quote the rest of the text. Not pretty, but it seems to work.

    return (c == " " and "\" \"") or (c:find("[^\\/%.%-%a%d]") and "^"..c)

  end

  

  shellString = function(filename)

    return filename == "" and "\"\"" or filename:gsub(".", shellEscapeCharacter)

  end

  

  fileState = function(filename)

    -- Use md5sum; slower than checking date, but I don't know of a

    -- good way to do that.

    local stream = io.popen(("md5sum -- %s"):format(shellString(filename)))

    if stream then

      local result = stream:read("*line")

      stream:close()

      return result

    end

    return

  end

elseif shell == "sh" or shell == "bash" then

  local function shellEscapeCharacter(c)

    return c:find("[^/%.%-%a%d]") and "\\"..c

  end

  

  shellString = function(filename)

    return filename == "" and "\"\"" or filename:gsub(".", shellEscapeCharacter)

  end

  

  fileState = function(filename)

    local stream = io.popen(("stat -Lc %%y -- %s"):format(shellString(filename)))

    if stream then

      local result = stream:read("*line")

      io.close(stream)

      return result or ""

    end

    return ""

  end

else

  error("Don't know how to safely escape strings for shell '"..shell.."'.")

end



-- Holds information about files that are open.

local buffers = {}



-- Returns a string containing the contents of a file.

local function fileData(filename)

  local stream = io.open(filename)

  if stream then

    local result = stream:read("*all")

    io.close(stream)

    return result or ""

  end

  return ""

end 



-- Returns the last known state of a file, or sets up a new state if the file wasn't known.

local function getBuffer(file)

  local buffer = buffers[file]

  

  if not buffer then

    buffer = {}

    buffers[file] = buffer

    buffer.state = fileState(file)

    buffer.data = fileData(file)

  end

  

  return buffer

end



-- Returns the name of a temporary file containing the passed string.

local function dataToFile(data)

  local file = os.tmpname()

  local stream = io.open(file, "w")

  stream:write(data)

  stream:close()

  return file

end



-- Merges some strings, and returns the result.

--   orig is the state of the file before editing occured

--   new is what the file on disk currently looks like

local function mergeData(orig, new)

  local current = editor:GetText()

  current, orig, new = dataToFile(current), dataToFile(orig), dataToFile(new)

  

  -- We use diff3 to merge the files together, and

  -- then we use diff to discover the changes needed to transform

  -- the text in the buffer into the merged file.

  -- Then we manually apply those changes, rather than dumping the

  -- merged file into the buffer, so that folds, bookmarks, and selections

  -- are (more or less) preserved.

  local stream = io.popen(("diff3 -mE --strip-trailing-cr -L Local -L Original -L Disk %s %s %s | diff %s -")

                          :format(shellString(current),

                                  shellString(orig),

                                  shellString(new),

                                  shellString(current)))

  

  if stream then

    local conflicts = {}

    local eol = "\n"

    

    if editor.EOLMode == 0 then eol = "\r\n"

    elseif editor.EOLMode == 1 then eol = "\r" end

    

    local p = 1

    local line = stream:read("*line")

    

    editor:BeginUndoAction()

    

    while line do

      local action, pos = line:match("^%d[,%d]-([acd])(%d+)")

      if action then

        p = tonumber(pos)

        if action == "d" then

          -- Position of deleted text is kind of inconsistant in my opinion, but

          -- considering non-existent things don't usually have positions,

          -- I suppose I should be greatful.

          p = p + 1

        end

      end

      

      local cmd, txt = line:match("^(.).(.*)$")

      

      if cmd == "<" then

        local a = editor.Anchor

        editor.TargetStart = editor:PositionFromLine(p-1)

        editor.TargetEnd = editor.TargetStart+editor:LineLength(p-1)

        if a >= editor.TargetStart then

          if a >= editor.TargetEnd then a = a - (editor.TargetEnd-editor.TargetStart)

          else a = editor.TargetStart

          end

        end

        editor:ReplaceTarget("")

        editor.Anchor = a

      elseif cmd == ">" then

        local a = editor.Anchor

        local pos = editor:PositionFromLine(p-1)

        editor:InsertText(pos, txt..eol)

        if a >= pos then

          a = a + txt:len() + eol:len()

        end

        editor.Anchor = a

        if txt == "=======" then

          table.insert(conflicts, p)

          editor:MarkerAdd(p-1, 1) -- And a bookmark for this conflict.

        end

        p = p + 1

      end

      

      line = stream:read("*line")

    end

    

    editor:EndUndoAction()

    

    if #conflicts > 0 then

      print("Merge conflicts on lines: "..table.concat(conflicts, ", ").."\n")

    end

    

    stream:close()

  end

  

  os.remove(current)

  os.remove(orig)

  os.remove(new)

end



-- Check if a file has been modified, and merge it if needed.

local function recheckFile(file)

  -- The file being checked damn well better be the file in the editor.

  assert(file == props["FilePath"])

  

  local buffer = getBuffer(file)

  local state = fileState(file)

  if state ~= buffer.state then

    local data= fileData(file)

    

    if data ~= buffer.data then

      mergeData(buffer.data, data)

    end

    

    buffer.state = state

    buffer.data = data

  end

end



local function onSwitch(file)

  recheckFile(file)

end



local function onClose(file)

  buffers[file] = nil

end



local function onOpen(file)

  onClose(file) -- Forget everything we know about the file.

  getBuffer(file) -- This will recreate the state information for the file.

end



local function onBeforeSave(file)

  recheckFile(file)

end



local function onSave(file)

  -- Pretend the file was just opened.

  onOpen(file)

end



local function onFocus()

  recheckFile(props["FilePath"])

end



local function register(name, func)

  if _G["scite_"..name] then

    -- Use extman's register function if it exists.

    _G["scite_"..name](func)

  else

    local orig = _G[name]

    if orig then

      -- If there is already a function, replace it with a new one that will call both

      -- ours and the original.

      _G[name] = function(...) return func(...) or orig(...) end

    else

      -- If the function doesn't exist, use our own.

      _G[name] = func

    end

  end

end



register("OnOpen", onOpen)

register("OnBeforeSave", onBeforeSave)

register("OnSave", onSave)

register("OnClose", onClose)

register("OnSwitchFile", onSwitch)



-- Don't do this on Windows, because it makes the command prompt flash over the screen,

-- which is annoying.

if shell then

  -- I'd rather only check when SciTE regains focus after the user returns to it

  -- after using another program, but this will have to do.

  register("OnUpdateUI", onFocus)

end



_G.moc_checkFile = function()

  recheckFile(props["FilePath"])

end



if scite_Command then

  -- Add shortcut using extman.

  scite_Command("Merge External Changes|moc_checkFile")

else

  -- Add shortcut manually.

  local i = 1

  

  while props["command.name."..i..".*"] ~= "" and -- Search for unused index, 

        props["command.name."..i..".*"] ~= "Merge External Changes" do -- Or our old index if SciTE reloaded this script.

    i = i + 1

  end

  

  props["command.name."..i..".*"] = "Merge External Changes"

  props["command."..i..".*"] = "moc_checkFile"

  props["command.subsystem."..i..".*"] = "3"

  props["command.mode."..i..".*"]="savebefore:no"

end