[FAR luajit module]

piper.lua

--https://forum.farmanager.com/viewtopic.php?f=60&t=8696&p=167904#p167904
-- based on https://forum.farmanager.com/viewtopic.php?t=8696
local SYNTAX = [[
Executes a specified command, putting the specified text to it's input stream,
and providing convenient access to the command's output/err.

Syntax: obj = sh.piper(cmdline [,options])
  cmdline: a string specifying the command to be executed

  options: a table with optional keys:
  - directory: a string specifying the working directory for the command
  - input: a string representing the text to be provided as input to the command
  - isOem: a boolean, if true then CP en-/decoding performed
  - linewrap: a number specifying the maximum width for each line of output

  obj: a table with the following keys:
  - all: a string containing all the output generated by the executed command
  - chunks: an iterator function that returns the output in raw chunks
  - lines: an iterator function that returns the output line by line
  - streamlines: an iterator function that returns the output line by line
    in a stream-like manner. It adds more data to each line as it becomes available.
    The iterator keeps returning the same line with more data until it is complete,
    and then adds a second `true` value to indicate completion.
  - ExitCode: an integer representing the exit code of the command
    (obtained from GetExitCodeProcess)
]]

local function split (str, wrapAt)
  local e, e2 = string.find(str, "[\r\n]")
  local rest, ln
  if e then
    if string.sub(str, e, e+1)=="\r\n" then e2 = e+1 end
    str, ln, rest = string.sub(str, 1, e-1), string.sub(str, e, e2), string.sub(str, e2+1)
  end
  if wrapAt and str:len()>wrapAt then
    local pos = str:find("%S", wrapAt+1)
    if pos==wrapAt+1 then
      pos = str:sub(1, wrapAt):find("%S+$")
      if not pos or pos==1 then pos = wrapAt+1 end
    end
    if pos then
      local tail = str:sub(pos)
      rest = rest and tail..ln..rest or tail
      str = str:sub(1, pos-1)--:match"^(.-)%s*$"
    end
  end
  return str, rest--, ln or ""
end

--[[
local function _lines (getchunk, wrapAt)
  local rest
  return function ()
    repeat
      if rest then
        local line; line,rest = split(rest, wrapAt)
        if rest then return line end
        rest = line
      end
      local chunk = getchunk()
      if chunk then
        rest = rest and rest..chunk or chunk
      end
    until chunk==nil
    return rest~="" and rest or nil
  end
end
--]]

local function _streamlines (getchunk, wrapAt)
  local rest
  local curline = ""
  return function (last)
    if last then return curline end
    if not rest then
      rest = getchunk()
      if rest==nil then return end
    end
    local line; line,rest = split(curline..rest, wrapAt)
    curline = not rest and line or ""
    return line, rest
  end
end

local function _lines (getchunk, wrapAt)
  local getter = _streamlines(getchunk, wrapAt)
  return function ()
    if not getter then return end
    repeat
      local line, rest = getter()
      if rest then return line end
    until not line
    local lastline = getter"lastline"
    getter = nil
    return lastline
  end
end


local ffi = require("ffi")
local C = ffi.C
local function safe_cdef(def)
  pcall(ffi.cdef, def)
end
safe_cdef([[
  typedef struct _STARTUPINFOW {
    unsigned long cb;
    wchar_t* lpReserved;
    wchar_t* lpDesktop;
    wchar_t* lpTitle;
    unsigned long dwX;
    unsigned long dwY;
    unsigned long dwXSize;
    unsigned long dwYSize;
    unsigned long dwXCountChars;
    unsigned long dwYCountChars;
    unsigned long dwFillAttribute;
    unsigned long dwFlags;
    unsigned short wShowWindow;
    unsigned short cbReserved2;
    unsigned char* lpReserved2;
    void* hStdInput;
    void* hStdOutput;
    void* hStdError;
  } STARTUPINFOW;
]])
safe_cdef([[
  typedef struct _PROCESS_INFORMATION {
    void* hProcess;
    void* hThread;
    unsigned long dwProcessId;
    unsigned long dwThreadId;
  } PROCESS_INFORMATION;
]])

ffi.cdef[[
int32_t CreatePipe(void** hReadPipe,void** hWritePipe,SECURITY_ATTRIBUTES* lpPipeAttributes,unsigned long nSize);
int32_t CreateProcessW(const wchar_t* lpApplicationName,wchar_t* lpCommandLine,SECURITY_ATTRIBUTES* lpProcessAttributes,SECURITY_ATTRIBUTES* lpThreadAttributes,int32_t bInheritHandles,unsigned long dwCreationFlags,void* lpEnvironment,const wchar_t* lpCurrentDirectory,STARTUPINFOW* lpStartupInfo,PROCESS_INFORMATION* lpProcessInformation);
int32_t ReadFile(void* hFile,void* lpBuffer,unsigned long nNumberOfBytesToRead,unsigned long* lpNumberOfBytesRead,void* lpOverlapped);
int32_t CloseHandle(void* hObject);
void* GetStdHandle(unsigned long nStdHandle);
int32_t IsTextUnicode(const void* lpv,int iSize,int* lpiResult);
]]
ffi.cdef[[
//https://learn.microsoft.com/windows/win32/api/handleapi/nf-handleapi-sethandleinformation
BOOL SetHandleInformation(
  HANDLE hObject,
  DWORD  dwMask,
  DWORD  dwFlags
);
//https://learn.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-writefile
BOOL WriteFile(
  HANDLE       hFile,
  LPCVOID      lpBuffer,
  DWORD        nNumberOfBytesToWrite,
  LPDWORD      lpNumberOfBytesWritten,
  void* lpOverlapped
);
//https://learn.microsoft.com/windows/win32/api/processthreadsapi/nf-processthreadsapi-getexitcodeprocess
BOOL GetExitCodeProcess(
  HANDLE  hProcess,
  LPDWORD lpExitCode
);
//https://learn.microsoft.com/windows/win32/api/synchapi/nf-synchapi-waitforsingleobject
DWORD WaitForSingleObject(
  HANDLE hHandle,
  DWORD  dwMilliseconds
);
//https://learn.microsoft.com/windows/win32/api/errhandlingapi/nf-errhandlingapi-getlasterror
DWORD GetLastError();
]]
local HANDLE_FLAG_INHERIT = 0x00000001
local STILL_ACTIVE = 259
-- https://learn.microsoft.com/windows/win32/debug/system-error-codes--0-499-#ERROR_BROKEN_PIPE
local ERROR_BROKEN_PIPE = 109

local function bAssert (fn, source)
  return function (...)
    local res = fn(...)
    if res==0 then
      far.Message(debug.traceback(source):gsub("\t","   "), "Error", nil, "ewl")
      return false
    end
    return res
  end
end
local CreatePipe = bAssert(C.CreatePipe, "CreatePipe")
local CreateProcessW = bAssert(C.CreateProcessW, "CreateProcessW")
--local ReadFile = bAssert(C.ReadFile, "ReadFile")
local CloseHandle = bAssert(C.CloseHandle, "CloseHandle")
local SetHandleInformation = bAssert(C.SetHandleInformation, "SetHandleInformation")
local WriteFile = bAssert(C.WriteFile, "WriteFile")
local GetExitCodeProcess = bAssert(C.GetExitCodeProcess, "GetExitCodeProcess")

local advapi32 = ffi.load("advapi32")
local unicode = ffi.new("int[1]")
local IS_TEXT_UNICODE_ASCII16 = 0x0001
local IS_TEXT_UNICODE_STATISTICS = 0x0002
--https://learn.microsoft.com/windows/win32/api/winbase/nf-winbase-istextunicode
local function IsTextUnicode (buffer, len)
  unicode[0] = bit64.bor(IS_TEXT_UNICODE_ASCII16, IS_TEXT_UNICODE_STATISTICS)
  return advapi32.IsTextUnicode(buffer,len,unicode)~=0
end

local CREATE_NO_WINDOW = 0x8000000
local STD_INPUT_HANDLE = -10
local STARTF_USESTDHANDLES = 0x00000100

local function ToWChar (str)
  str = win.Utf8ToUtf16(str)
  local result = ffi.new("wchar_t[?]", #str/2+1)
  ffi.copy(result,str)
  return result
end

local function exists (directory)
  local attr = win.GetFileAttr(directory)
  return attr and attr:match"d"
end

local function piper (command, options)
  options = options or {}
  local directory, input = options.directory, options.input
  assert(not directory or exists(directory), "Directory does not exist")
  local pipe_security = ffi.new("SECURITY_ATTRIBUTES", ffi.sizeof("SECURITY_ATTRIBUTES"), nil, true)
  local pipe_outRd, pipe_outWr = ffi.new("void*[1]"), ffi.new("void*[1]")
  if not CreatePipe(pipe_outRd, pipe_outWr, pipe_security, 0) or
     not SetHandleInformation(pipe_outRd[0], HANDLE_FLAG_INHERIT, 0) then
    return
  end
  local pipe_inRd,pipe_inWr
  if input then
    pipe_inRd, pipe_inWr = ffi.new("void*[1]"), ffi.new("void*[1]")
    if not CreatePipe(pipe_inRd, pipe_inWr, pipe_security, 0) or
       not SetHandleInformation(pipe_inWr[0], HANDLE_FLAG_INHERIT, 0) then
      return
    end
  end
  local info = ffi.new("PROCESS_INFORMATION")
  local startup = ffi.new("STARTUPINFOW")
  startup.cb = ffi.sizeof(startup)
  startup.dwFlags = STARTF_USESTDHANDLES
  startup.hStdError = pipe_outWr[0]
  startup.hStdOutput = pipe_outWr[0]
  startup.hStdInput = input and pipe_inRd[0] or C.GetStdHandle(STD_INPUT_HANDLE)
  if not CreateProcessW(ffi.NULL, ToWChar(command), ffi.NULL, ffi.NULL, true, CREATE_NO_WINDOW,
                        ffi.NULL, directory and ToWChar(directory), startup, info) then
    return
  end
  CloseHandle(info.hThread)
  CloseHandle(pipe_outWr[0])
  if input then
    CloseHandle(pipe_inRd[0])
    local written = ffi.new("DWORD[1]")
    input = options.isOem and win.Utf8ToOem(input) or input
    if not WriteFile(pipe_inWr[0], input, string.len(input), written, ffi.NULL) then
      return
    end
    CloseHandle(pipe_inWr[0])
    --assert(written[0]==string.len(input))
  end

  local size=4096
  local buffer=ffi.new("char[?]",size)
  local readed=ffi.new("unsigned long[1]")
  ffi.gc(pipe_outRd, function (arr) C.CloseHandle(arr[0]) end)
  local out_chunks = function ()
    local success = C.ReadFile(pipe_outRd[0], buffer, size, readed, ffi.NULL)
    local lasterr = success==0 and C.GetLastError()
    if lasterr or readed[0]==0 then
      if lasterr and lasterr~=ERROR_BROKEN_PIPE then -- The pipe has been ended.
        far.Message("ReadFile:", "Error", nil, "ewl")
      end
      CloseHandle(ffi.gc(pipe_outRd, nil)[0])
    else
      local str = ffi.string(buffer, readed[0])
      if options.isOem then
        str = (IsTextUnicode(buffer, readed[0]) and win.Utf16ToUtf8 or win.OemToUtf8)(str)
      end
      return str
    end
  end
  local res = {
    lines=_lines(out_chunks, options.linewrap),
    streamlines=_streamlines(out_chunks, options.linewrap),
    chunks=out_chunks,
    hProcess=ffi.gc(info.hProcess, C.CloseHandle)
  }
  local exitcode = ffi.new("DWORD[1]")
  local timeout = 500
  return setmetatable(res, {
    __index=function (t,k)
      if k=="all" then
        local out = {}
        for chunk in out_chunks do
          out[#out+1] = chunk
        end
        t.all = table.concat(out)
        return t.all
      elseif k=="ExitCode" then
        C.WaitForSingleObject(info.hProcess, timeout)
        GetExitCodeProcess(info.hProcess, exitcode)
        if exitcode[0]~=STILL_ACTIVE then
          t.ExitCode = exitcode[0]
          CloseHandle(ffi.gc(info.hProcess, nil))
        end
        return exitcode[0]
      end
    end
  })
end

if _cmdline=="" then
  print(SYNTAX)
  --[[ -- examples:
  local command = "cmd /c type piper.lua"
  print(sh.piper(command).all)
  for line in sh.piper(command).lines do print(line) end
  --]]
elseif _cmdline then
  --print(piper(_cmdline:eval()).all)
  for line in piper(_cmdline:eval()).lines do print(line) end
  return
else
  return piper
end