mcs/tools/csharp/getline.cs

   1 //
   2 // getline.cs: A command line editor
   3 //
   4 // Authors:
   5 //   Miguel de Icaza (miguel@novell.com)
   6 //
   7 // Copyright 2008 Novell, Inc.
   8 // Copyright 2016 Xamarin Inc
   9 //
  10 // Completion wanted:
  11 //
  12 //   * Enable bash-like completion window the window as an option for non-GUI people?
  13 //
  14 //   * Continue completing when Backspace is used?
  15 //
  16 //   * Should we keep the auto-complete on "."?
  17 //
  18 //   * Completion produces an error if the value is not resolvable, we should hide those errors
  19 //
  20 // Dual-licensed under the terms of the MIT X11 license or the
  21 // Apache License 2.0
  22 //
  23 // USE -define:DEMO to build this as a standalone file and test it
  24 //
  25 // TODO:
  26 //    Enter an error (a = 1);  Notice how the prompt is in the wrong line
  27 //              This is caused by Stderr not being tracked by System.Console.
  28 //    Completion support
  29 //    Why is Thread.Interrupt not working?   Currently I resort to Abort which is too much.
  30 //
  31 // Limitations in System.Console:
  32 //    Console needs SIGWINCH support of some sort
  33 //    Console needs a way of updating its position after things have been written
  34 //    behind its back (P/Invoke puts for example).
  35 //    System.Console needs to get the DELETE character, and report accordingly.
  36 //
  37 // Bug:
  38 //   About 8 lines missing, type "Con<TAB>" and not enough lines are inserted at the bottom.
  39 //
  40 //
  41 using System;
  42 using System.Text;
  43 using System.IO;
  44 using System.Threading;
  45 using System.Reflection;
  46
  47 namespace Mono.Terminal {
  48
  49         public class LineEditor {
  50
  51                 public class Completion {
  52                         public string [] Result;
  53                         public string Prefix;
  54
  55                         public Completion (string prefix, string [] result)
  56                         {
  57                                 Prefix = prefix;
  58                                 Result = result;
  59                         }
  60                 }
  61
  62                 public delegate Completion AutoCompleteHandler (string text, int pos);
  63
  64                 // null does nothing, "csharp" uses some heuristics that make sense for C#
  65                 public string HeuristicsMode;
  66
  67                 //static StreamWriter log;
  68
  69                 // The text being edited.
  70                 StringBuilder text;
  71
  72                 // The text as it is rendered (replaces (char)1 with ^A on display for example).
  73                 StringBuilder rendered_text;
  74
  75                 // The prompt specified, and the prompt shown to the user.
  76                 string prompt;
  77                 string shown_prompt;
  78
  79                 // The current cursor position, indexes into "text", for an index
  80                 // into rendered_text, use TextToRenderPos
  81                 int cursor;
  82
  83                 // The row where we started displaying data.
  84                 int home_row;
  85
  86                 // The maximum length that has been displayed on the screen
  87                 int max_rendered;
  88
  89                 // If we are done editing, this breaks the interactive loop
  90                 bool done = false;
  91
  92                 // The thread where the Editing started taking place
  93                 Thread edit_thread;
  94
  95                 // Our object that tracks history
  96                 History history;
  97
  98                 // The contents of the kill buffer (cut/paste in Emacs parlance)
  99                 string kill_buffer = "";
 100
 101                 // The string being searched for
 102                 string search;
 103                 string last_search;
 104
 105                 // whether we are searching (-1= reverse; 0 = no; 1 = forward)
 106                 int searching;
 107
 108                 // The position where we found the match.
 109                 int match_at;
 110
 111                 // Used to implement the Kill semantics (multiple Alt-Ds accumulate)
 112                 KeyHandler last_handler;
 113
 114                 // If we have a popup completion, this is not null and holds the state.
 115                 CompletionState current_completion;
 116
 117                 // If this is set, it contains an escape sequence to reset the Unix colors to the ones that were used on startup
 118                 static byte [] unix_reset_colors;
 119
 120                 // This contains a raw stream pointing to stdout, used to bypass the TermInfoDriver
 121                 static Stream unix_raw_output;
 122
 123                 delegate void KeyHandler ();
 124
 125                 struct Handler {
 126                         public ConsoleKeyInfo CKI;
 127                         public KeyHandler KeyHandler;
 128                         public bool ResetCompletion;
 129
 130                         public Handler (ConsoleKey key, KeyHandler h, bool resetCompletion = true)
 131                         {
 132                                 CKI = new ConsoleKeyInfo ((char) 0, key, false, false, false);
 133                                 KeyHandler = h;
 134                                 ResetCompletion = resetCompletion;
 135                         }
 136
 137                         public Handler (char c, KeyHandler h, bool resetCompletion = true)
 138                         {
 139                                 KeyHandler = h;
 140                                 // Use the "Zoom" as a flag that we only have a character.
 141                                 CKI = new ConsoleKeyInfo (c, ConsoleKey.Zoom, false, false, false);
 142                                 ResetCompletion = resetCompletion;
 143                         }
 144
 145                         public Handler (ConsoleKeyInfo cki, KeyHandler h, bool resetCompletion = true)
 146                         {
 147                                 CKI = cki;
 148                                 KeyHandler = h;
 149                                 ResetCompletion = resetCompletion;
 150                         }
 151
 152                         public static Handler Control (char c, KeyHandler h, bool resetCompletion = true)
 153                         {
 154                                 return new Handler ((char) (c - 'A' + 1), h, resetCompletion);
 155                         }
 156
 157                         public static Handler Alt (char c, ConsoleKey k, KeyHandler h)
 158                         {
 159                                 ConsoleKeyInfo cki = new ConsoleKeyInfo ((char) c, k, false, true, false);
 160                                 return new Handler (cki, h);
 161                         }
 162                 }
 163
 164                 /// <summary>
 165                 ///   Invoked when the user requests auto-completion using the tab character
 166                 /// </summary>
 167                 /// <remarks>
 168                 ///    The result is null for no values found, an array with a single
 169                 ///    string, in that case the string should be the text to be inserted
 170                 ///    for example if the word at pos is "T", the result for a completion
 171                 ///    of "ToString" should be "oString", not "ToString".
 172                 ///
 173                 ///    When there are multiple results, the result should be the full
 174                 ///    text
 175                 /// </remarks>
 176                 public AutoCompleteHandler AutoCompleteEvent;
 177
 178                 static Handler [] handlers;
 179
 180                 public LineEditor (string name) : this (name, 10) { }
 181
 182                 public LineEditor (string name, int histsize)
 183                 {
 184                         handlers = new Handler [] {
 185                                 new Handler (ConsoleKey.Home,       CmdHome),
 186                                 new Handler (ConsoleKey.End,        CmdEnd),
 187                                 new Handler (ConsoleKey.LeftArrow,  CmdLeft),
 188                                 new Handler (ConsoleKey.RightArrow, CmdRight),
 189                                 new Handler (ConsoleKey.UpArrow,    CmdUp, resetCompletion: false),
 190                                 new Handler (ConsoleKey.DownArrow,  CmdDown, resetCompletion: false),
 191                                 new Handler (ConsoleKey.Enter,      CmdDone, resetCompletion: false),
 192                                 new Handler (ConsoleKey.Backspace,  CmdBackspace, resetCompletion: false),
 193                                 new Handler (ConsoleKey.Delete,     CmdDeleteChar),
 194                                 new Handler (ConsoleKey.Tab,        CmdTabOrComplete, resetCompletion: false),
 195
 196                                 // Emacs keys
 197                                 Handler.Control ('A', CmdHome),
 198                                 Handler.Control ('E', CmdEnd),
 199                                 Handler.Control ('B', CmdLeft),
 200                                 Handler.Control ('F', CmdRight),
 201                                 Handler.Control ('P', CmdUp, resetCompletion: false),
 202                                 Handler.Control ('N', CmdDown, resetCompletion: false),
 203                                 Handler.Control ('K', CmdKillToEOF),
 204                                 Handler.Control ('Y', CmdYank),
 205                                 Handler.Control ('D', CmdDeleteChar),
 206                                 Handler.Control ('L', CmdRefresh),
 207                                 Handler.Control ('R', CmdReverseSearch),
 208                                 Handler.Control ('G', delegate {} ),
 209                                 Handler.Alt ('B', ConsoleKey.B, CmdBackwardWord),
 210                                 Handler.Alt ('F', ConsoleKey.F, CmdForwardWord),
 211
 212                                 Handler.Alt ('D', ConsoleKey.D, CmdDeleteWord),
 213                                 Handler.Alt ((char) 8, ConsoleKey.Backspace, CmdDeleteBackword),
 214
 215                                 // DEBUG
 216                                 //Handler.Control ('T', CmdDebug),
 217
 218                                 // quote
 219                                 Handler.Control ('Q', delegate { HandleChar (Console.ReadKey (true).KeyChar); })
 220                         };
 221
 222                         rendered_text = new StringBuilder ();
 223                         text = new StringBuilder ();
 224
 225                         history = new History (name, histsize);
 226
 227                         GetUnixConsoleReset ();
 228                         //if (File.Exists ("log"))File.Delete ("log");
 229                         //log = File.CreateText ("log");
 230                 }
 231
 232                 // On Unix, there is a "default" color which is not represented by any colors in
 233                 // ConsoleColor and it is not possible to set is by setting the ForegroundColor or
 234                 // BackgroundColor properties, so we have to use the terminfo driver in Mono to
 235                 // fetch these values
 236
 237                 void GetUnixConsoleReset ()
 238                 {
 239                         //
 240                         // On Unix, we want to be able to reset the color for the pop-up completion
 241                         //
 242                         int p = (int) Environment.OSVersion.Platform;
 243                         var is_unix = (p == 4) || (p == 128);
 244                         if (!is_unix)
 245                                 return;
 246
 247                         // Sole purpose of this call is to initialize the Terminfo driver
 248                         var x = Console.CursorLeft;
 249
 250                         try {
 251                                 var terminfo_driver = Type.GetType ("System.ConsoleDriver")?.GetField ("driver", BindingFlags.Static | BindingFlags.NonPublic)?.GetValue (null);
 252                                 if (terminfo_driver == null)
 253                                         return;
 254
 255                                 var unix_reset_colors_str = (terminfo_driver?.GetType ()?.GetField ("origPair", BindingFlags.Instance | BindingFlags.NonPublic))?.GetValue (terminfo_driver) as string;
 256
 257                                 if (unix_reset_colors_str != null)
 258                                         unix_reset_colors = Encoding.UTF8.GetBytes ((string)unix_reset_colors_str);
 259                                 unix_raw_output = Console.OpenStandardOutput ();
 260                         } catch (Exception e){
 261                                 Console.WriteLine ("Error: " + e);
 262                         }
 263                 }
 264
 265
 266                 void CmdDebug ()
 267                 {
 268                         history.Dump ();
 269                         Console.WriteLine ();
 270                         Render ();
 271                 }
 272
 273                 void Render ()
 274                 {
 275                         Console.Write (shown_prompt);
 276                         Console.Write (rendered_text);
 277
 278                         int max = System.Math.Max (rendered_text.Length + shown_prompt.Length, max_rendered);
 279
 280                         for (int i = rendered_text.Length + shown_prompt.Length; i < max_rendered; i++)
 281                                 Console.Write (' ');
 282                         max_rendered = shown_prompt.Length + rendered_text.Length;
 283
 284                         // Write one more to ensure that we always wrap around properly if we are at the
 285                         // end of a line.
 286                         Console.Write (' ');
 287
 288                         UpdateHomeRow (max);
 289                 }
 290
 291                 void UpdateHomeRow (int screenpos)
 292                 {
 293                         int lines = 1 + (screenpos / Console.WindowWidth);
 294
 295                         home_row = Console.CursorTop - (lines - 1);
 296                         if (home_row < 0)
 297                                 home_row = 0;
 298                 }
 299
 300
 301                 void RenderFrom (int pos)
 302                 {
 303                         int rpos = TextToRenderPos (pos);
 304                         int i;
 305
 306                         for (i = rpos; i < rendered_text.Length; i++)
 307                                 Console.Write (rendered_text [i]);
 308
 309                         if ((shown_prompt.Length + rendered_text.Length) > max_rendered)
 310                                 max_rendered = shown_prompt.Length + rendered_text.Length;
 311                         else {
 312                                 int max_extra = max_rendered - shown_prompt.Length;
 313                                 for (; i < max_extra; i++)
 314                                         Console.Write (' ');
 315                         }
 316                 }
 317
 318                 void ComputeRendered ()
 319                 {
 320                         rendered_text.Length = 0;
 321
 322                         for (int i = 0; i < text.Length; i++){
 323                                 int c = (int) text [i];
 324                                 if (c < 26){
 325                                         if (c == '\t')
 326                                                 rendered_text.Append ("    ");
 327                                         else {
 328                                                 rendered_text.Append ('^');
 329                                                 rendered_text.Append ((char) (c + (int) 'A' - 1));
 330                                         }
 331                                 } else
 332                                         rendered_text.Append ((char)c);
 333                         }
 334                 }
 335
 336                 int TextToRenderPos (int pos)
 337                 {
 338                         int p = 0;
 339
 340                         for (int i = 0; i < pos; i++){
 341                                 int c;
 342
 343                                 c = (int) text [i];
 344
 345                                 if (c < 26){
 346                                         if (c == 9)
 347                                                 p += 4;
 348                                         else
 349                                                 p += 2;
 350                                 } else
 351                                         p++;
 352                         }
 353
 354                         return p;
 355                 }
 356
 357                 int TextToScreenPos (int pos)
 358                 {
 359                         return shown_prompt.Length + TextToRenderPos (pos);
 360                 }
 361
 362                 string Prompt {
 363                         get { return prompt; }
 364                         set { prompt = value; }
 365                 }
 366
 367                 int LineCount {
 368                         get {
 369                                 return (shown_prompt.Length + rendered_text.Length)/Console.WindowWidth;
 370                         }
 371                 }
 372
 373                 void ForceCursor (int newpos)
 374                 {
 375                         cursor = newpos;
 376
 377                         int actual_pos = shown_prompt.Length + TextToRenderPos (cursor);
 378                         int row = home_row + (actual_pos/Console.WindowWidth);
 379                         int col = actual_pos % Console.WindowWidth;
 380
 381                         if (row >= Console.BufferHeight)
 382                                 row = Console.BufferHeight-1;
 383                         Console.SetCursorPosition (col, row);
 384
 385                         //log.WriteLine ("Going to cursor={0} row={1} col={2} actual={3} prompt={4} ttr={5} old={6}", newpos, row, col, actual_pos, prompt.Length, TextToRenderPos (cursor), cursor);
 386                         //log.Flush ();
 387                 }
 388
 389                 void UpdateCursor (int newpos)
 390                 {
 391                         if (cursor == newpos)
 392                                 return;
 393
 394                         ForceCursor (newpos);
 395                 }
 396
 397                 void InsertChar (char c)
 398                 {
 399                         int prev_lines = LineCount;
 400                         text = text.Insert (cursor, c);
 401                         ComputeRendered ();
 402                         if (prev_lines != LineCount){
 403
 404                                 Console.SetCursorPosition (0, home_row);
 405                                 Render ();
 406                                 ForceCursor (++cursor);
 407                         } else {
 408                                 RenderFrom (cursor);
 409                                 ForceCursor (++cursor);
 410                                 UpdateHomeRow (TextToScreenPos (cursor));
 411                         }
 412                 }
 413
 414                 static void SaveExcursion (Action code)
 415                 {
 416                         var saved_col = Console.CursorLeft;
 417                         var saved_row = Console.CursorTop;
 418                         var saved_fore = Console.ForegroundColor;
 419                         var saved_back = Console.BackgroundColor;
 420
 421                         code ();
 422
 423                         Console.CursorLeft = saved_col;
 424                         Console.CursorTop = saved_row;
 425                         if (unix_reset_colors != null){
 426                                 unix_raw_output.Write (unix_reset_colors, 0, unix_reset_colors.Length);
 427                         } else {
 428                                 Console.ForegroundColor = saved_fore;
 429                                 Console.BackgroundColor = saved_back;
 430                         }
 431                 }
 432
 433                 class CompletionState {
 434                         public string Prefix;
 435                         public string [] Completions;
 436                         public int Col, Row, Width, Height;
 437                         int selected_item, top_item;
 438
 439                         public CompletionState (int col, int row, int width, int height)
 440                         {
 441                                 Col = col;
 442                                 Row = row;
 443                                 Width = width;
 444                                 Height = height;
 445
 446                                 if (Col < 0)
 447                                         throw new ArgumentException ("Cannot be less than zero" + Col, "Col");
 448                                 if (Row < 0)
 449                                         throw new ArgumentException ("Cannot be less than zero", "Row");
 450                                 if (Width < 1)
 451                                         throw new ArgumentException ("Cannot be less than one", "Width");
 452                                 if (Height < 1)
 453                                         throw new ArgumentException ("Cannot be less than one", "Height");
 454
 455                         }
 456
 457                         void DrawSelection ()
 458                         {
 459                                 for (int r = 0; r < Height; r++){
 460                                         int item_idx = top_item + r;
 461                                         bool selected = (item_idx == selected_item);
 462
 463                                         Console.ForegroundColor = selected ? ConsoleColor.Black : ConsoleColor.Gray;
 464                                         Console.BackgroundColor = selected ? ConsoleColor.Cyan : ConsoleColor.Blue;
 465
 466                                         var item = Prefix + Completions [item_idx];
 467                                         if (item.Length > Width)
 468                                                 item = item.Substring (0, Width);
 469
 470                                         Console.CursorLeft = Col;
 471                                         Console.CursorTop = Row + r;
 472                                         Console.Write (item);
 473                                         for (int space = item.Length; space <= Width; space++)
 474                                                 Console.Write (" ");
 475                                 }
 476                         }
 477
 478                         public string Current {
 479                                 get {
 480                                         return Completions [selected_item];
 481                                 }
 482                         }
 483
 484                         public void Show ()
 485                         {
 486                                 SaveExcursion (DrawSelection);
 487                         }
 488
 489                         public void SelectNext ()
 490                         {
 491                                 if (selected_item+1 < Completions.Length){
 492                                         selected_item++;
 493                                         if (selected_item - top_item >= Height)
 494                                                 top_item++;
 495                                         SaveExcursion (DrawSelection);
 496                                 }
 497                         }
 498
 499                         public void SelectPrevious ()
 500                         {
 501                                 if (selected_item > 0){
 502                                         selected_item--;
 503                                         if (selected_item < top_item)
 504                                                 top_item = selected_item;
 505                                         SaveExcursion (DrawSelection);
 506                                 }
 507                         }
 508
 509                         void Clear ()
 510                         {
 511                                 for (int r = 0; r < Height; r++){
 512                                         Console.CursorLeft = Col;
 513                                         Console.CursorTop = Row + r;
 514                                         for (int space = 0; space <= Width; space++)
 515                                                 Console.Write (" ");
 516                                 }
 517                         }
 518
 519                         public void Remove ()
 520                         {
 521                                 SaveExcursion (Clear);
 522                         }
 523                 }
 524
 525                 void ShowCompletions (string prefix, string [] completions)
 526                 {
 527                         // Ensure we have space, determine window size
 528                         int window_height = System.Math.Min (completions.Length, Console.WindowHeight/5);
 529                         int target_line = Console.WindowHeight-window_height-1;
 530                         if (Console.CursorTop > target_line){
 531                                 var saved_left = Console.CursorLeft;
 532                                 var delta = Console.CursorTop-target_line;
 533                                 Console.CursorLeft = 0;
 534                                 Console.CursorTop = Console.WindowHeight-1;
 535                                 for (int i = 0; i < delta+1; i++){
 536                                         for (int c = Console.WindowWidth; c > 0; c--)
 537                                                 Console.Write (" "); // To debug use ("{0}", i%10);
 538                                 }
 539                                 Console.CursorTop = target_line;
 540                                 Console.CursorLeft = 0;
 541                                 Render ();
 542                         }
 543
 544                         const int MaxWidth = 50;
 545                         int window_width = 12;
 546                         int plen = prefix.Length;
 547                         foreach (var s in completions)
 548                                 window_width = System.Math.Max (plen + s.Length, window_width);
 549                         window_width = System.Math.Min (window_width, MaxWidth);
 550
 551                         if (current_completion == null){
 552                                 int left = Console.CursorLeft-prefix.Length;
 553
 554                                 if (left + window_width + 1 >= Console.WindowWidth)
 555                                         left = Console.WindowWidth-window_width-1;
 556
 557                                 current_completion = new CompletionState (left, Console.CursorTop+1, window_width, window_height) {
 558                                         Prefix = prefix,
 559                                         Completions = completions,
 560                                 };
 561                         } else {
 562                                 current_completion.Prefix = prefix;
 563                                 current_completion.Completions = completions;
 564                         }
 565                         current_completion.Show ();
 566                         Console.CursorLeft = 0;
 567                 }
 568
 569                 void HideCompletions ()
 570                 {
 571                         if (current_completion == null)
 572                                 return;
 573                         current_completion.Remove ();
 574                         current_completion = null;
 575                 }
 576
 577                 //
 578                 // Triggers the completion engine, if insertBestMatch is true, then this will
 579                 // insert the best match found, this behaves like the shell "tab" which will
 580                 // complete as much as possible given the options.
 581                 //
 582                 void Complete ()
 583                 {
 584                         Completion completion = AutoCompleteEvent (text.ToString (), cursor);
 585                         string [] completions = completion.Result;
 586                         if (completions == null){
 587                                 HideCompletions ();
 588                                 return;
 589                         }
 590
 591                         int ncompletions = completions.Length;
 592                         if (ncompletions == 0){
 593                                 HideCompletions ();
 594                                 return;
 595                         }
 596
 597                         if (completions.Length == 1){
 598                                 InsertTextAtCursor (completions [0]);
 599                         } else {
 600                                 int last = -1;
 601
 602                                 for (int p = 0; p < completions [0].Length; p++){
 603                                         char c = completions [0][p];
 604
 605
 606                                         for (int i = 1; i < ncompletions; i++){
 607                                                 if (completions [i].Length < p)
 608                                                         goto mismatch;
 609
 610                                                 if (completions [i][p] != c){
 611                                                         goto mismatch;
 612                                                 }
 613                                         }
 614                                         last = p;
 615                                 }
 616                         mismatch:
 617                                 var prefix = completion.Prefix;
 618                                 if (last != -1){
 619                                         InsertTextAtCursor (completions [0].Substring (0, last+1));
 620
 621                                         // Adjust the completions to skip the common prefix
 622                                         prefix += completions [0].Substring (0, last+1);
 623                                         for (int i = 0; i < completions.Length; i++)
 624                                                 completions [i] = completions [i].Substring (last+1);
 625                                 }
 626                                 ShowCompletions (prefix, completions);
 627                                 Render ();
 628                                 ForceCursor (cursor);
 629                         }
 630                 }
 631
 632                 //
 633                 // When the user has triggered a completion window, this will try to update
 634                 // the contents of it.   The completion window is assumed to be hidden at this
 635                 // point
 636                 //
 637                 void UpdateCompletionWindow ()
 638                 {
 639                         if (current_completion != null)
 640                                 throw new Exception ("This method should only be called if the window has been hidden");
 641
 642                         Completion completion = AutoCompleteEvent (text.ToString (), cursor);
 643                         string [] completions = completion.Result;
 644                         if (completions == null)
 645                                 return;
 646
 647                         int ncompletions = completions.Length;
 648                         if (ncompletions == 0)
 649                                 return;
 650
 651                         ShowCompletions (completion.Prefix, completion.Result);
 652                         Render ();
 653                         ForceCursor (cursor);
 654                 }
 655
 656
 657                 //
 658                 // Commands
 659                 //
 660                 void CmdDone ()
 661                 {
 662                         if (current_completion != null){
 663                                 InsertTextAtCursor (current_completion.Current);
 664                                 HideCompletions ();
 665                                 return;
 666                         }
 667                         done = true;
 668                 }
 669
 670                 void CmdTabOrComplete ()
 671                 {
 672                         bool complete = false;
 673
 674                         if (AutoCompleteEvent != null){
 675                                 if (TabAtStartCompletes)
 676                                         complete = true;
 677                                 else {
 678                                         for (int i = 0; i < cursor; i++){
 679                                                 if (!Char.IsWhiteSpace (text [i])){
 680                                                         complete = true;
 681                                                         break;
 682                                                 }
 683                                         }
 684                                 }
 685
 686                                 if (complete)
 687                                         Complete ();
 688                                 else
 689                                         HandleChar ('\t');
 690                         } else
 691                                 HandleChar ('t');
 692                 }
 693
 694                 void CmdHome ()
 695                 {
 696                         UpdateCursor (0);
 697                 }
 698
 699                 void CmdEnd ()
 700                 {
 701                         UpdateCursor (text.Length);
 702                 }
 703
 704                 void CmdLeft ()
 705                 {
 706                         if (cursor == 0)
 707                                 return;
 708
 709                         UpdateCursor (cursor-1);
 710                 }
 711
 712                 void CmdBackwardWord ()
 713                 {
 714                         int p = WordBackward (cursor);
 715                         if (p == -1)
 716                                 return;
 717                         UpdateCursor (p);
 718                 }
 719
 720                 void CmdForwardWord ()
 721                 {
 722                         int p = WordForward (cursor);
 723                         if (p == -1)
 724                                 return;
 725                         UpdateCursor (p);
 726                 }
 727
 728                 void CmdRight ()
 729                 {
 730                         if (cursor == text.Length)
 731                                 return;
 732
 733                         UpdateCursor (cursor+1);
 734                 }
 735
 736                 void RenderAfter (int p)
 737                 {
 738                         ForceCursor (p);
 739                         RenderFrom (p);
 740                         ForceCursor (cursor);
 741                 }
 742
 743                 void CmdBackspace ()
 744                 {
 745                         if (cursor == 0)
 746                                 return;
 747
 748                         bool completing = current_completion != null;
 749                         HideCompletions ();
 750
 751                         text.Remove (--cursor, 1);
 752                         ComputeRendered ();
 753                         RenderAfter (cursor);
 754                         if (completing)
 755                                 UpdateCompletionWindow ();
 756                 }
 757
 758                 void CmdDeleteChar ()
 759                 {
 760                         // If there is no input, this behaves like EOF
 761                         if (text.Length == 0){
 762                                 done = true;
 763                                 text = null;
 764                                 Console.WriteLine ();
 765                                 return;
 766                         }
 767
 768                         if (cursor == text.Length)
 769                                 return;
 770                         text.Remove (cursor, 1);
 771                         ComputeRendered ();
 772                         RenderAfter (cursor);
 773                 }
 774
 775                 int WordForward (int p)
 776                 {
 777                         if (p >= text.Length)
 778                                 return -1;
 779
 780                         int i = p;
 781                         if (Char.IsPunctuation (text [p]) || Char.IsSymbol (text [p]) || Char.IsWhiteSpace (text[p])){
 782                                 for (; i < text.Length; i++){
 783                                         if (Char.IsLetterOrDigit (text [i]))
 784                                             break;
 785                                 }
 786                                 for (; i < text.Length; i++){
 787                                         if (!Char.IsLetterOrDigit (text [i]))
 788                                             break;
 789                                 }
 790                         } else {
 791                                 for (; i < text.Length; i++){
 792                                         if (!Char.IsLetterOrDigit (text [i]))
 793                                             break;
 794                                 }
 795                         }
 796                         if (i != p)
 797                                 return i;
 798                         return -1;
 799                 }
 800
 801                 int WordBackward (int p)
 802                 {
 803                         if (p == 0)
 804                                 return -1;
 805
 806                         int i = p-1;
 807                         if (i == 0)
 808                                 return 0;
 809
 810                         if (Char.IsPunctuation (text [i]) || Char.IsSymbol (text [i]) || Char.IsWhiteSpace (text[i])){
 811                                 for (; i >= 0; i--){
 812                                         if (Char.IsLetterOrDigit (text [i]))
 813                                                 break;
 814                                 }
 815                                 for (; i >= 0; i--){
 816                                         if (!Char.IsLetterOrDigit (text[i]))
 817                                                 break;
 818                                 }
 819                         } else {
 820                                 for (; i >= 0; i--){
 821                                         if (!Char.IsLetterOrDigit (text [i]))
 822                                                 break;
 823                                 }
 824                         }
 825                         i++;
 826
 827                         if (i != p)
 828                                 return i;
 829
 830                         return -1;
 831                 }
 832
 833                 void CmdDeleteWord ()
 834                 {
 835                         int pos = WordForward (cursor);
 836
 837                         if (pos == -1)
 838                                 return;
 839
 840                         string k = text.ToString (cursor, pos-cursor);
 841
 842                         if (last_handler == CmdDeleteWord)
 843                                 kill_buffer = kill_buffer + k;
 844                         else
 845                                 kill_buffer = k;
 846
 847                         text.Remove (cursor, pos-cursor);
 848                         ComputeRendered ();
 849                         RenderAfter (cursor);
 850                 }
 851
 852                 void CmdDeleteBackword ()
 853                 {
 854                         int pos = WordBackward (cursor);
 855                         if (pos == -1)
 856                                 return;
 857
 858                         string k = text.ToString (pos, cursor-pos);
 859
 860                         if (last_handler == CmdDeleteBackword)
 861                                 kill_buffer = k + kill_buffer;
 862                         else
 863                                 kill_buffer = k;
 864
 865                         text.Remove (pos, cursor-pos);
 866                         ComputeRendered ();
 867                         RenderAfter (pos);
 868                 }
 869
 870                 //
 871                 // Adds the current line to the history if needed
 872                 //
 873                 void HistoryUpdateLine ()
 874                 {
 875                         history.Update (text.ToString ());
 876                 }
 877
 878                 void CmdHistoryPrev ()
 879                 {
 880                         if (!history.PreviousAvailable ())
 881                                 return;
 882
 883                         HistoryUpdateLine ();
 884
 885                         SetText (history.Previous ());
 886                 }
 887
 888                 void CmdHistoryNext ()
 889                 {
 890                         if (!history.NextAvailable())
 891                                 return;
 892
 893                         history.Update (text.ToString ());
 894                         SetText (history.Next ());
 895
 896                 }
 897
 898                 void CmdUp ()
 899                 {
 900                         if (current_completion == null)
 901                                 CmdHistoryPrev ();
 902                         else
 903                                 current_completion.SelectPrevious ();
 904                 }
 905
 906                 void CmdDown ()
 907                 {
 908                         if (current_completion == null)
 909                                 CmdHistoryNext ();
 910                         else
 911                                 current_completion.SelectNext ();
 912                 }
 913
 914                 void CmdKillToEOF ()
 915                 {
 916                         kill_buffer = text.ToString (cursor, text.Length-cursor);
 917                         text.Length = cursor;
 918                         ComputeRendered ();
 919                         RenderAfter (cursor);
 920                 }
 921
 922                 void CmdYank ()
 923                 {
 924                         InsertTextAtCursor (kill_buffer);
 925                 }
 926
 927                 void InsertTextAtCursor (string str)
 928                 {
 929                         int prev_lines = LineCount;
 930                         text.Insert (cursor, str);
 931                         ComputeRendered ();
 932                         if (prev_lines != LineCount){
 933                                 Console.SetCursorPosition (0, home_row);
 934                                 Render ();
 935                                 cursor += str.Length;
 936                                 ForceCursor (cursor);
 937                         } else {
 938                                 RenderFrom (cursor);
 939                                 cursor += str.Length;
 940                                 ForceCursor (cursor);
 941                                 UpdateHomeRow (TextToScreenPos (cursor));
 942                         }
 943                 }
 944
 945                 void SetSearchPrompt (string s)
 946                 {
 947                         SetPrompt ("(reverse-i-search)`" + s + "': ");
 948                 }
 949
 950                 void ReverseSearch ()
 951                 {
 952                         int p;
 953
 954                         if (cursor == text.Length){
 955                                 // The cursor is at the end of the string
 956
 957                                 p = text.ToString ().LastIndexOf (search);
 958                                 if (p != -1){
 959                                         match_at = p;
 960                                         cursor = p;
 961                                         ForceCursor (cursor);
 962                                         return;
 963                                 }
 964                         } else {
 965                                 // The cursor is somewhere in the middle of the string
 966                                 int start = (cursor == match_at) ? cursor - 1 : cursor;
 967                                 if (start != -1){
 968                                         p = text.ToString ().LastIndexOf (search, start);
 969                                         if (p != -1){
 970                                                 match_at = p;
 971                                                 cursor = p;
 972                                                 ForceCursor (cursor);
 973                                                 return;
 974                                         }
 975                                 }
 976                         }
 977
 978                         // Need to search backwards in history
 979                         HistoryUpdateLine ();
 980                         string s = history.SearchBackward (search);
 981                         if (s != null){
 982                                 match_at = -1;
 983                                 SetText (s);
 984                                 ReverseSearch ();
 985                         }
 986                 }
 987
 988                 void CmdReverseSearch ()
 989                 {
 990                         if (searching == 0){
 991                                 match_at = -1;
 992                                 last_search = search;
 993                                 searching = -1;
 994                                 search = "";
 995                                 SetSearchPrompt ("");
 996                         } else {
 997                                 if (search == ""){
 998                                         if (last_search != "" && last_search != null){
 999                                                 search = last_search;
1000                                                 SetSearchPrompt (search);
1001
1002                                                 ReverseSearch ();
1003                                         }
1004                                         return;
1005                                 }
1006                                 ReverseSearch ();
1007                         }
1008                 }
1009
1010                 void SearchAppend (char c)
1011                 {
1012                         search = search + c;
1013                         SetSearchPrompt (search);
1014
1015                         //
1016                         // If the new typed data still matches the current text, stay here
1017                         //
1018                         if (cursor < text.Length){
1019                                 string r = text.ToString (cursor, text.Length - cursor);
1020                                 if (r.StartsWith (search))
1021                                         return;
1022                         }
1023
1024                         ReverseSearch ();
1025                 }
1026
1027                 void CmdRefresh ()
1028                 {
1029                         Console.Clear ();
1030                         max_rendered = 0;
1031                         Render ();
1032                         ForceCursor (cursor);
1033                 }
1034
1035                 void InterruptEdit (object sender, ConsoleCancelEventArgs a)
1036                 {
1037                         // Do not abort our program:
1038                         a.Cancel = true;
1039
1040                         // Interrupt the editor
1041                         edit_thread.Abort();
1042                 }
1043
1044                 //
1045                 // Implements heuristics to show the completion window based on the mode
1046                 //
1047                 bool HeuristicAutoComplete (bool wasCompleting, char insertedChar)
1048                 {
1049                         if (HeuristicsMode == "csharp"){
1050                                 // csharp heuristics
1051                                 if (wasCompleting){
1052                                         if (insertedChar == ' '){
1053                                                 return false;
1054                                         }
1055                                         return true;
1056                                 }
1057                                 // If we were not completing, determine if we want to now
1058                                 if (insertedChar == '.'){
1059                                         // Avoid completing for numbers "1.2" for example
1060                                         if (cursor > 1 && Char.IsDigit (text[cursor-2])){
1061                                                 for (int p = cursor-3; p >= 0; p--){
1062                                                         char c = text[p];
1063                                                         if (Char.IsDigit (c))
1064                                                                 continue;
1065                                                         if (c == '_')
1066                                                                 return true;
1067                                                         if (Char.IsLetter (c) || Char.IsPunctuation (c) || Char.IsSymbol (c) || Char.IsControl (c))
1068                                                                 return true;
1069                                                 }
1070                                                 return false;
1071                                         }
1072                                         return true;
1073                                 }
1074                         }
1075                         return false;
1076                 }
1077
1078                 void HandleChar (char c)
1079                 {
1080                         if (searching != 0)
1081                                 SearchAppend (c);
1082                         else {
1083                                 bool completing = current_completion != null;
1084                                 HideCompletions ();
1085
1086                                 InsertChar (c);
1087                                 if (HeuristicAutoComplete (completing, c))
1088                                         UpdateCompletionWindow ();
1089                         }
1090                 }
1091
1092                 void EditLoop ()
1093                 {
1094                         ConsoleKeyInfo cki;
1095
1096                         while (!done){
1097                                 ConsoleModifiers mod;
1098
1099                                 cki = Console.ReadKey (true);
1100                                 if (cki.Key == ConsoleKey.Escape){
1101                                         if (current_completion != null){
1102                                                 HideCompletions ();
1103                                                 continue;
1104                                         } else {
1105                                                 cki = Console.ReadKey (true);
1106
1107                                                 mod = ConsoleModifiers.Alt;
1108                                         }
1109                                 } else
1110                                         mod = cki.Modifiers;
1111
1112                                 bool handled = false;
1113
1114                                 foreach (Handler handler in handlers){
1115                                         ConsoleKeyInfo t = handler.CKI;
1116
1117                                         if (t.Key == cki.Key && t.Modifiers == mod){
1118                                                 handled = true;
1119                                                 if (handler.ResetCompletion)
1120                                                         HideCompletions ();
1121                                                 handler.KeyHandler ();
1122                                                 last_handler = handler.KeyHandler;
1123                                                 break;
1124                                         } else if (t.KeyChar == cki.KeyChar && t.Key == ConsoleKey.Zoom){
1125                                                 handled = true;
1126                                                 if (handler.ResetCompletion)
1127                                                         HideCompletions ();
1128
1129                                                 handler.KeyHandler ();
1130                                                 last_handler = handler.KeyHandler;
1131                                                 break;
1132                                         }
1133                                 }
1134                                 if (handled){
1135                                         if (searching != 0){
1136                                                 if (last_handler != CmdReverseSearch){
1137                                                         searching = 0;
1138                                                         SetPrompt (prompt);
1139                                                 }
1140                                         }
1141                                         continue;
1142                                 }
1143
1144                                 if (cki.KeyChar != (char) 0){
1145                                         HandleChar (cki.KeyChar);
1146                                 }
1147                         }
1148                 }
1149
1150                 void InitText (string initial)
1151                 {
1152                         text = new StringBuilder (initial);
1153                         ComputeRendered ();
1154                         cursor = text.Length;
1155                         Render ();
1156                         ForceCursor (cursor);
1157                 }
1158
1159                 void SetText (string newtext)
1160                 {
1161                         Console.SetCursorPosition (0, home_row);
1162                         InitText (newtext);
1163                 }
1164
1165                 void SetPrompt (string newprompt)
1166                 {
1167                         shown_prompt = newprompt;
1168                         Console.SetCursorPosition (0, home_row);
1169                         Render ();
1170                         ForceCursor (cursor);
1171                 }
1172
1173                 public string Edit (string prompt, string initial)
1174                 {
1175                         edit_thread = Thread.CurrentThread;
1176                         searching = 0;
1177                         Console.CancelKeyPress += InterruptEdit;
1178
1179                         done = false;
1180                         history.CursorToEnd ();
1181                         max_rendered = 0;
1182
1183                         Prompt = prompt;
1184                         shown_prompt = prompt;
1185                         InitText (initial);
1186                         history.Append (initial);
1187
1188                         do {
1189                                 try {
1190                                         EditLoop ();
1191                                 } catch (ThreadAbortException){
1192                                         searching = 0;
1193                                         Thread.ResetAbort ();
1194                                         Console.WriteLine ();
1195                                         SetPrompt (prompt);
1196                                         SetText ("");
1197                                 }
1198                         } while (!done);
1199                         Console.WriteLine ();
1200
1201                         Console.CancelKeyPress -= InterruptEdit;
1202
1203                         if (text == null){
1204                                 history.Close ();
1205                                 return null;
1206                         }
1207
1208                         string result = text.ToString ();
1209                         if (result != "")
1210                                 history.Accept (result);
1211                         else
1212                                 history.RemoveLast ();
1213
1214                         return result;
1215                 }
1216
1217                 public void SaveHistory ()
1218                 {
1219                         if (history != null) {
1220                                 history.Close ();
1221                         }
1222                 }
1223
1224                 public bool TabAtStartCompletes { get; set; }
1225
1226                 //
1227                 // Emulates the bash-like behavior, where edits done to the
1228                 // history are recorded
1229                 //
1230                 class History {
1231                         string [] history;
1232                         int head, tail;
1233                         int cursor, count;
1234                         string histfile;
1235
1236                         public History (string app, int size)
1237                         {
1238                                 if (size < 1)
1239                                         throw new ArgumentException ("size");
1240
1241                                 if (app != null){
1242                                         string dir = Environment.GetFolderPath (Environment.SpecialFolder.ApplicationData);
1243                                         //Console.WriteLine (dir);
1244                                         if (!Directory.Exists (dir)){
1245                                                 try {
1246                                                         Directory.CreateDirectory (dir);
1247                                                 } catch {
1248                                                         app = null;
1249                                                 }
1250                                         }
1251                                         if (app != null)
1252                                                 histfile = Path.Combine (dir, app) + ".history";
1253                                 }
1254
1255                                 history = new string [size];
1256                                 head = tail = cursor = 0;
1257
1258                                 if (File.Exists (histfile)){
1259                                         using (StreamReader sr = File.OpenText (histfile)){
1260                                                 string line;
1261
1262                                                 while ((line = sr.ReadLine ()) != null){
1263                                                         if (line != "")
1264                                                                 Append (line);
1265                                                 }
1266                                         }
1267                                 }
1268                         }
1269
1270                         public void Close ()
1271                         {
1272                                 if (histfile == null)
1273                                         return;
1274
1275                                 try {
1276                                         using (StreamWriter sw = File.CreateText (histfile)){
1277                                                 int start = (count == history.Length) ? head : tail;
1278                                                 for (int i = start; i < start+count; i++){
1279                                                         int p = i % history.Length;
1280                                                         sw.WriteLine (history [p]);
1281                                                 }
1282                                         }
1283                                 } catch {
1284                                         // ignore
1285                                 }
1286                         }
1287
1288                         //
1289                         // Appends a value to the history
1290                         //
1291                         public void Append (string s)
1292                         {
1293                                 //Console.WriteLine ("APPENDING {0} head={1} tail={2}", s, head, tail);
1294                                 history [head] = s;
1295                                 head = (head+1) % history.Length;
1296                                 if (head == tail)
1297                                         tail = (tail+1 % history.Length);
1298                                 if (count != history.Length)
1299                                         count++;
1300                                 //Console.WriteLine ("DONE: head={1} tail={2}", s, head, tail);
1301                         }
1302
1303                         //
1304                         // Updates the current cursor location with the string,
1305                         // to support editing of history items.   For the current
1306                         // line to participate, an Append must be done before.
1307                         //
1308                         public void Update (string s)
1309                         {
1310                                 history [cursor] = s;
1311                         }
1312
1313                         public void RemoveLast ()
1314                         {
1315                                 head = head-1;
1316                                 if (head < 0)
1317                                         head = history.Length-1;
1318                         }
1319
1320                         public void Accept (string s)
1321                         {
1322                                 int t = head-1;
1323                                 if (t < 0)
1324                                         t = history.Length-1;
1325
1326                                 history [t] = s;
1327                         }
1328
1329                         public bool PreviousAvailable ()
1330                         {
1331                                 //Console.WriteLine ("h={0} t={1} cursor={2}", head, tail, cursor);
1332                                 if (count == 0)
1333                                         return false;
1334                                 int next = cursor-1;
1335                                 if (next < 0)
1336                                         next = count-1;
1337
1338                                 if (next == head)
1339                                         return false;
1340
1341                                 return true;
1342                         }
1343
1344                         public bool NextAvailable ()
1345                         {
1346                                 if (count == 0)
1347                                         return false;
1348                                 int next = (cursor + 1) % history.Length;
1349                                 if (next == head)
1350                                         return false;
1351                                 return true;
1352                         }
1353
1354
1355                         //
1356                         // Returns: a string with the previous line contents, or
1357                         // nul if there is no data in the history to move to.
1358                         //
1359                         public string Previous ()
1360                         {
1361                                 if (!PreviousAvailable ())
1362                                         return null;
1363
1364                                 cursor--;
1365                                 if (cursor < 0)
1366                                         cursor = history.Length - 1;
1367
1368                                 return history [cursor];
1369                         }
1370
1371                         public string Next ()
1372                         {
1373                                 if (!NextAvailable ())
1374                                         return null;
1375
1376                                 cursor = (cursor + 1) % history.Length;
1377                                 return history [cursor];
1378                         }
1379
1380                         public void CursorToEnd ()
1381                         {
1382                                 if (head == tail)
1383                                         return;
1384
1385                                 cursor = head;
1386                         }
1387
1388                         public void Dump ()
1389                         {
1390                                 Console.WriteLine ("Head={0} Tail={1} Cursor={2} count={3}", head, tail, cursor, count);
1391                                 for (int i = 0; i < history.Length;i++){
1392                                         Console.WriteLine (" {0} {1}: {2}", i == cursor ? "==>" : "   ", i, history[i]);
1393                                 }
1394                                 //log.Flush ();
1395                         }
1396
1397                         public string SearchBackward (string term)
1398                         {
1399                                 for (int i = 0; i < count; i++){
1400                                         int slot = cursor-i-1;
1401                                         if (slot < 0)
1402                                                 slot = history.Length+slot;
1403                                         if (slot >= history.Length)
1404                                                 slot = 0;
1405                                         if (history [slot] != null && history [slot].IndexOf (term) != -1){
1406                                                 cursor = slot;
1407                                                 return history [slot];
1408                                         }
1409                                 }
1410
1411                                 return null;
1412                         }
1413
1414                 }
1415         }
1416
1417 #if DEMO
1418         class Demo {
1419                 static void Main ()
1420                 {
1421                         LineEditor le = new LineEditor ("foo") {
1422                                 HeuristicsMode = "csharp"
1423                         };
1424                         le.AutoCompleteEvent += delegate (string a, int pos){
1425                                 string prefix = "";
1426                                 var completions = new string [] { "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine", "Ten" };
1427                                 return new Mono.Terminal.LineEditor.Completion (prefix, completions);
1428                         };
1429
1430                         string s;
1431
1432                         while ((s = le.Edit ("shell> ", "")) != null){
1433                                 Console.WriteLine ("----> [{0}]", s);
1434                         }
1435                 }
1436         }
1437 #endif
1438 }