Initial landing of Screen, Terminal, and VT100 classes.

chrome/browser/resources/hterm/js/vt100.js

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+/**
+ * @fileoverview This file implements the VT100 interpreter, which
+ * operates in conjunction with a hterm.Terminal to provide
+ * interpretation of VT100-style control sequences.
+ *
+ * Original code by Cory Maccarrone.
+ */
+
+/**
+ * Constructor for the VT100 Interpreter.
+ *
+ * The interpreter operates on a terminal object capable of performing cursor
+ * move operations, painting characters, etc.
+ *
+ * @param {hterm.Terminal} terminal Terminal to use with
+ *     the interpreter.  Direct commands are sent to it in the presence of
+ *     control characters -- otherwise, normal characters are passed straight
+ *     through to its render functions.
+ * @constructor
+ */
+hterm.VT100 = function(terminal) {
+  this.terminal_ = terminal;
+
+  // Sequence being processed -- that seen so far
+  this.pendingSequence_ = [];
+
+  // Response to be sent back to the guest
+  this.pendingResponse_ = '';
+
+  // Keyboard flags, stored here as we interpret the control sequences that
+  // change them.
+  this.applicationKeypad_ = false;
+  this.applicationCursor_ = false;
+  this.backspaceSendsBackspace_ = false;
+  this.altSendsEscape_ = true;
+  this.metaSendsEscape_ = true;
+};
+
+/**
+ * Interpret a sequence of characters.
+ *
+ * Incomplete escape sequences are buffered until the next call.
+ *
+ * @param {string} str Sequence of characters to interpret or pass through.
+ */
+hterm.VT100.prototype.interpretString = function(str) {
+  var i = 0;
+
+  while (i < str.length) {
+    while (this.pendingSequence_.length && i < str.length) {
+      this.interpretCharacter(str.substr(i, 1));
+      i++;
+    }
+
+    if (i == str.length)
+      break;
+
+    var nextEscape = str.substr(i).search(/[\x1b\n\t]|$/);
+
+    if (nextEscape == -1)
+      nextEscape = str.length;
+
+    if (nextEscape != 0) {
+      var plainText = str.substr(i, nextEscape);
+      this.terminal_.print(plainText);
+      i += nextEscape;
+    }
+
+    if (i == str.length)
+      break;
+
+    this.interpretCharacter(str.substr(i, 1));
+    i++;
+  }
+};
+
+/**
+ * Interpret a single character in a sequence.
+ *
+ * This function is called for each character in terminal input, and
+ * accumulates characters until a recognized control sequence is read.  If the
+ * character is not part of a control sequence, it is queued up for rendering.
+ *
+ * @param {string} character Character to interpret or pass through.
+ */
+hterm.VT100.prototype.interpretCharacter = function(character) {
+  var interpret = false;
+
+  // Check if this is either an escape, a bell, or a printable character.  These
+  // are all part of escape sequences.  Others may be intermingled in escape
+  // sequences, and they'll be picked out and sent to the renderer.  This is per
+  // VT100 spec.
+  if (character == '\x1b' ||
+      ((character >= '\x20' || character == '\x07') &&
+       this.pendingSequence_.length)) {

[klimek, 2011/11/24 19:13:51]

Can't you save this whole 'interpret' variable by just inverting the if here and
pulling up the block below?

[rginda, 2011/11/28 20:39:47]

This wonkyness is a result of some changes I made to the original code.  I had
meant to revisit this code but forgot to.  Fixed now.

+    interpret = true;
+  }
+
+  if (!interpret) {
+    // Other characters are printed to the terminal.
+    if (character == '\n') {
+      this.terminal_.newLine();
+      return;
+    }
+
+    if (character == '\t') {
+      this.terminal_.cursorRight(4);
+      return;
+    }
+
+    this.terminal_.print(character);
+    return;
+  }
+
+  this.pendingSequence_.push(character);
+  var sequence = this.pendingSequence_;
+
+  if (sequence.length == 0 ||

[klimek, 2011/11/24 19:13:51]

== 0 cannot happen after a push; or am I missing something fundamental?

[rginda, 2011/11/28 20:39:47]

Done.

+      sequence[0] != '\x1b' ||

[klimek, 2011/11/24 19:13:51]

Also, I don't see how this code can every push something other than \x1b at the
start of the sequence...

[rginda, 2011/11/28 20:39:47]

Done.

+      sequence.length < 2) {

[klimek, 2011/11/24 19:13:51]

... so this is basically if (sequence.length == 1) { ... }

[rginda, 2011/11/28 20:39:47]

Done.

+    // This isn't a sequence, or it isn't log enough, return.
+    return;
+  }
+
+  var processed = true;
+  switch (sequence[1]) {
+    case '\x1b':
+      // Another escape, restart processing from this char
+      this.pendingSequence_.length = 1;
+      processed = false;
+      break;
+
+    case '[':
+      if (!this.interpretControlSequenceInducer_(sequence.slice(2))) {
+        processed = false;
+      }
+      break;
+
+    case ']':
+      if (!this.interpretOperatingSystemCommand_(sequence.slice(2))) {
+        processed = false;
+      }
+      break;
+
+    case '=':  // Application keypad
+      this.setApplicationKeypad(true);
+      break;
+
+    case '>':  // Normal keypad
+      this.setApplicationKeypad(false);
+      break;
+
+    case '7':  // Save cursor
+      this.terminal_.saveCursor();
+      break;
+
+    case '8':  // Restore cursor
+      this.terminal_.restoreCursor();
+      break;
+
+    case 'D':  // Index, like newline, only keep the X position
+      this.terminal_.lineFeed();
+      break;
+
+    case 'E':  // Next line.  Like newline, but doesn't add lines.
+      this.terminal_.setCursorColumn(0);
+      this.terminal_.cursorDown(1);
+      break;
+
+    case 'M':  // Reverse index.
+      // This is like newline, but in reverse.  When we hit the top of the
+      // terminal, lines are added at the top while swapping out the bottom
+      // lines.
+      this.terminal_.reverseLineFeed();
+      break;
+
+    case 'c':  // Full reset
+      this.terminal_.reset();
+      break;
+
+    case '#':  // DEC commands
+      if (sequence.length < 3) {
+        processed = false;
+        break;
+      }
+      switch (sequence[2]) {
+        case '8':  // DEC screen alignment test
+          this.fill('E');
+          break;
+        default:
+          console.log('Unsupported DEC command: ' + sequence[2]);
+          break;
+      }
+      break;
+
+    case '(':  // Designate G0 character set
+      if (sequence.length < 3) {
+        processed = false;
+        break;
+      }
+      switch (sequence[2]) {
+        case '0':  // Line drawing
+          this.terminal_.setSpecialCharsEnabled(true);
+          break;
+        default:
+          this.terminal_.setSpecialCharsEnabled(false);
+          break;
+      }
+      break;
+
+    case ')':  // Designate G1 character set
+    case '*':  // Designate G2 character set
+    case '+':  // Designate G3 character set
+      if (sequence.length < 3) {
+        processed = false;
+        break;
+      }
+      console.log('Code ' + sequence[2]);
+      break;
+
+    case 'H':  // Set a tab stop at the cursor position
+      this.terminal_.setTabStopAtCursor(true);
+      break;
+
+    default:
+      console.log('Unsupported escape sequence: ' + sequence[1]);
+      break;
+  }
+
+  if (processed) {
+    //console.log('Escape sequence: ' + sequence.slice(1));
+    this.pendingSequence_.length = 0;
+  }
+
+  return;
+};
+
+/**
+ * Return any pending response from the interpretation of control sequences.
+ *
+ * The response should be returned as if the user typed it, and the pending
+ * response is cleared from the interpreter.
+ *
+ * @return {string} response to send.
+ */
+hterm.VT100.prototype.getAndClearPendingResponse = function() {
+  var response = this.pendingResponse_;
+  this.pendingResponse_ = '';
+  return response;
+};
+
+/**
+ * Set whether backspace should send ^H
+ *
+ * @param {boolean} enable Whether backspace should send ^H or not.
+ */
+hterm.VT100.prototype.setBackspaceSendsBackspace =
+    function(enable) {
+  this.backspaceSendsBackspace_ = enable;
+};
+
+/**
+ * Return whether backspace should send ^H
+ *
+ * @return {boolean} Whether backspace should send ^H or not.
+ */
+hterm.VT100.prototype.getBackspaceSendsBackspace =
+    function() {
+  return this.backspaceSendsBackspace_;
+};
+
+/**
+ * Set whether the meta key sends a leading escape or not.
+ *
+ * @param {boolean} enable Whether meta sends a leading escape or not.
+ */
+hterm.VT100.prototype.setMetaSendsEscape = function(enable) {
+  this.metaSendsEscape_ = enable;

[arv (Not doing code reviews), 2011/11/28 18:21:00]

All these noop getters and setters are pretty silly. Why don't you just use data
properties and real getters and setters for the few cases where side effects are
wanted?

[rginda, 2011/11/28 20:39:47]

I avoid real getters and setters like the plague (sorry, I know you're into
them).  I'm not a fan of the fact that they look like a simple get/set, but
actually have side-effects.  I've been bitten in enough in various languages --
by myself and others -- and now I just avoid them everywhere as a matter of
course.  They're also pretty ugly in programmatic class construction.  (Sorry
again, we agree that programmatic get/setters are ugly, but I know you prefer to
declare your objects in literal notation!)

But, I can agree that the accessor methods on VT100 are unnecessary :)  I've
converted them all to public properties.

Promoting (demoting?) the setters related to Terminal.options_ will have much
more fallout.  I'll do that in another CL.

+};
+
+/**
+ * Return whether the meta key sends a leading escape or not.
+ *
+ * @return {boolean} Whether meta sends a leading escape or not.
+ */
+hterm.VT100.prototype.getMetaSendsEscape = function() {
+  return this.metaSendsEscape_;
+};
+
+/**
+ * Set whether the alt key sends a leading escape or not.
+ *
+ * @param {boolean} enable Whether alt sends a leading escape or not.
+ */
+hterm.VT100.prototype.setAltSendsEscape = function(enable) {
+  this.altSendsEscape_ = enable;
+};
+
+/**
+ * Return whether the alt key sends a leading escape or not.
+ *
+ * @return {boolean} Whether alt sends a leading escape or not.
+ */
+hterm.VT100.prototype.getAltSendsEscape = function() {
+  return this.altSendsEscape_;
+};
+
+/**
+ * Enable/disable application keypad.  This changes the way numeric keys are
+ * sent from the keyboard.
+ *
+ * @param {boolean} enabled Whether the application keypad should be enabled or
+ *     not.
+ */
+hterm.VT100.prototype.setApplicationKeypad =
+    function(enabled) {
+  this.applicationKeypad_ = enabled;
+};
+
+/**
+ * Enable/disable the application cursor mode.
+ *
+ * This changes the way cursor keys are sent from the keyboard.
+ *
+ * @param {boolean} enabled Whether the application cursor keys are enabled or
+ *     not.
+ */
+hterm.VT100.prototype.setApplicationCursor =
+    function(enabled) {
+  this.applicationCursor_ = enabled;
+};
+
+/**
+ * Get the current application cursor mode.
+ *
+ * @return {boolean} Whether application cursor mode is enabled.
+ */
+hterm.VT100.prototype.getApplicationCursor = function() {
+  return this.applicationCursor_;
+};
+
+/**
+ * Interpret an operating system command (OSC) sequence.
+ *
+ * @param {Array} sequence Sequence to interpret.
+ * @return {boolean} Whether the sequence was interpreted or not.
+ * @private
+ */
+hterm.VT100.prototype.interpretOperatingSystemCommand_ =
+    function(sequence) {
+  // These commands tend to do things like change the window title and other
+  // things.
+  var processed = false;
+  var length = sequence.length;
+  var i = 0;
+  var args = [];
+  var currentArg = '';
+  var leadingZeroFilter = true;
+
+  // Parse the command into a sequence command and series of numeric arguments.
+  while (true) {
+    if (i >= length) {
+      // We ran out of characters interpreting the string
+      break;
+    }
+
+    if (sequence[i] == ';') {
+      // New argument
+      args.push(currentArg);
+      currentArg = '';
+      leadingZeroFilter = true;
+    } else if (sequence[i] == '\x7' ||
+               (sequence[i] == '\x1b' &&
+                sequence[i + 1] == '\\')) {
+      // Terminating character.  This'll tell us how to interpret the control
+      // sequence.
+      if (currentArg != '') {
+        args.push(currentArg);
+      }
+      processed = true;
+      break;
+    } else {
+      // Part of the arg, just add it, filtering out leadining zeros.
+      if (!(leadingZeroFilter && sequence[i] == '0')) {
+        leadingZeroFilter = false;
+        currentArg += sequence[i];
+      }
+    }
+    i++;
+  }
+
+  if (!processed)
+    return processed;
+
+  // Interpret the command
+  if (args[0] == '') {
+    // The leading-zero filter dropped our zero, so put it back.
+    args[0] = 0;
+  }
+
+  switch (parseInt(args[0], 10)) {
+    case 0:
+    case 2:
+      // Change the window title to args[1]
+      // TODO(rginda): this.
+      break;
+    default:
+      console.log('Unsupported OSC command: ' + sequence.slice(0, i + 1));
+      break;
+  }
+
+  return processed;
+};
+
+/**
+ * Interpret a control sequence inducer (CSI) command.
+ *
+ * @param {Array} sequence Sequence to interpret.
+ * @return {boolean} Whether the sequence was interpreted succesfully or not.
+ * @private
+ */
+hterm.VT100.prototype.interpretControlSequenceInducer_ =
+    function(sequence) {
+  // These escape codes all end with a letter, and have arguments separated by
+  // a semicolon.
+  var processed = false;
+  var args = [];
+  var currentArg = '';
+  var terminator = /[A-Za-z@]/;
+  var seqCommand = '';
+  var query = false;
+  var leadingZeroFilter = true;
+
+  // Parse the command into a sequence command and series of numeric arguments.
+  for (var i = 0; i < sequence.length; ++i) {
+    if (sequence[i] == '?') {
+      // Some commands have different meaning with a leading '?'.  We'll call
+      // that the 'query' flag.
+      query = true;
+      leadingZeroFilter = true;
+    } else if (sequence[i] == ';') {
+      // New argument
+      args.push(parseInt(currentArg, 10));
+      currentArg = '';
+      leadingZeroFilter = true;
+    } else if (terminator.test(sequence[i])) {
+      // Terminating character.  This'll tell us how to interpret the control
+      // sequence.
+      seqCommand = sequence[i];
+      if (currentArg != '') {
+        args.push(parseInt(currentArg, 10));
+      }
+      processed = true;
+      break;
+    } else {
+      // Part of the arg, just add it, filtering out leading zeros.
+      if (!(leadingZeroFilter && sequence[i] == '0')) {
+        leadingZeroFilter = false;
+        currentArg += sequence[i];
+      }
+    }
+  }
+
+  if (!processed) {
+    return processed;
+  }
+
+  // Interpret the command
+  switch (seqCommand) {
+    case 'A':  // Cursor up
+      this.terminal_.cursorUp(args[0] || 1);
+      break;
+
+    case 'B':  // Cursor down
+      this.terminal_.cursorDown(args[0] || 1);
+      break;
+
+    case 'C':  // Cursor right
+      this.terminal_.cursorRight(args[0] || 1);
+      break;
+
+    case 'D':  // Cursor left
+      this.terminal_.cursorLeft(args[0] || 1);
+      break;
+
+    case 'E':  // Next line
+      // This is like Cursor Down, except the cursor moves to the beginning of
+      // the line as well.
+      this.terminal_.cursorDown(args[0] || 1);
+      this.terminal_.setCursorColumn(0);
+      break;
+
+    case 'F':  // Previous line
+      // This is like Cursor Up, except the cursor moves to the beginning of the
+      // line as well.
+      this.terminal_.cursorUp(args[0] || 1);
+      this.terminal_.setCursorColumn(0);
+      break;
+
+    case 'G':  // Cursor absolute column
+      var position = args[0] ? args[0] - 1 : 0;
+      this.terminal_.setCursorColumn(position);
+      break;
+
+    case 'H':  // Cursor absolute row;col
+    case 'f':  // Horizontal & Vertical Position
+      var row = args[0] ? args[0] - 1 : 0;
+      var col = args[1] ? args[1] - 1 : 0;
+      this.terminal_.setCursorPosition(row, col);
+      break;
+
+    case 'K':  // Erase in Line
+      switch (args[0]) {
+        case 1:  // Erase to left
+          this.terminal_.eraseToLeft();
+          break;
+        case 2:  // Erase the line
+          this.terminal_.eraseLine();
+          break;
+        case 0:  // Erase to right
+        default:
+          // Erase to right
+          this.terminal_.eraseToRight();
+          break;
+      }
+      break;
+
+    case 'J':  // Erase in display
+      switch (args[0]) {
+        case 1:  // Erase above
+          this.terminal_.eraseToLeft();
+          this.terminal_.eraseAbove();
+          break;
+        case 2:  // Erase all
+          this.terminal_.clear();
+          break;
+        case 0:  // Erase below
+        default:
+          this.terminal_.eraseToRight();
+          this.terminal_.eraseBelow();
+          break;
+      }
+      break;
+
+    case 'X':  // Erase character
+      this.terminal_.eraseToRight(args[0] || 1);
+      break;
+
+    case 'L':  // Insert lines
+      this.terminal_.insertLines(args[0] || 1);
+      break;
+
+    case 'M':  // Delete lines
+      this.terminal_.deleteLines(args[0] || 1);
+      break;
+
+    case '@':  // Insert characters
+      var amount = 1;
+      if (args[0]) {
+        amount = args[0];
+      }
+      this.terminal_.insertSpace(amount);
+      break;
+
+    case 'P':  // Delete characters
+      // This command shifts the line contents left, starting at the cursor
+      // position.
+      this.terminal_.deleteChars(args[0] || 1);
+      break;
+
+    case 'S':  // Scroll up an amount
+      this.terminal_.vtScrollUp(args[0] || 1);
+      break;
+
+    case 'T':  // Scroll down an amount
+      this.terminal_.vtScrollDown(args[0] || 1);
+      break;
+
+    case 'c':  // Send device attributes
+      if (!args[0]) {
+        this.pendingResponse_ += '\x1b[?1;2c';
+      }
+      break;
+
+    case 'd':  // Line position absolute
+      this.terminal_.setCursorRow((args[0] - 1) || 0);
+      break;
+
+    case 'g':  // Clear tab stops
+      switch (args[0] || 0) {
+        case 0:
+          this.terminal_.setTabStopAtCursor(false);
+          break;
+        case 3:  // Clear all tab stops in the page
+          this.terminal_.clearTabStops();
+          break;
+        default:
+          break;
+      }
+      break;
+
+    case 'm':  // Color change
+      if (args.length == 0) {
+        this.terminal_.clearColorAndAttributes();
+      } else {
+        if (args.length == 3 &&
+            (args[0] == 38 || args[0] == 48) && args[1] == 5) {
+          // This is code for the 256-color palette, skip the normal processing.
+          if (args[0] == 38) {
+            // Set the foreground color to the 3rd argument.
+            this.terminal_.setForegroundColor256(args[2]);
+          } else if (args[0] == 48) {
+            // Set the background color to the 3rd argument.
+            this.terminal_.setBackgroundColor256(args[2]);
+          }
+        } else {
+          var numArgs = args.length;
+          for (var argNum = 0; argNum < numArgs; ++argNum) {
+            var arg = args[argNum];
+            if (isNaN(arg)) {
+              // This is the same as an attribute of zero.
+              this.terminal_.setAttributes(0);
+            } else if (arg < 30) {
+              // This is an attribute argument.
+              this.terminal_.setAttributes(arg);
+            } else if (arg < 40) {
+              // This is a foreground color argument.
+              this.terminal_.setForegroundColor(arg);
+            } else if (arg < 50) {
+              // This is a background color argument.
+              this.terminal_.setBackgroundColor(arg);
+            }
+          }
+        }
+      }
+      break;
+
+    case 'n':  // Device status report
+      switch (args[0]) {
+        case 5:
+          if (!query) {
+            var response = '\x1b0n';
+            this.pendingResponse_ += response;
+          }
+          break;
+
+        case 6:
+          var curX = this.terminal_.getCursorColumn() + 1;
+          var curY = this.terminal_.getCursorRow() + 1;
+          var response = '\x1b[' + curY + ';' + curX + 'R';
+          this.pendingResponse_ += response;
+          break;
+      }
+      break;
+
+    case 'l':  // Reset mode
+    case 'h':  // Set mode
+      var set = (seqCommand == 'h' ? true : false);
+      if (query) {
+        switch (args[0]) {
+          case 1:  // Normal (l) or application (h) cursor keys
+            this.setApplicationCursor(set);
+            break;
+          case 3:  // 80 (if l) or 132 (if h) column mode
+            // Our size is always determined by the window size, so we ignore
+            // attempts to resize from remote end.
+            break;
+          case 4:  // Fast (l) or slow (h) scroll
+            // This is meaningless to us.
+            break;
+          case 5:  // Normal (l) or reverse (h) video mode
+            this.terminal_.setReverseVideo(set);
+            break;
+          case 6:  // Normal (l) or origin (h) cursor mode
+            this.terminal_.setOriginMode(set);
+            break;
+          case 7:  // No (l) wraparound mode or wraparound (h) mode
+            this.terminal_.setWraparound(set);
+            break;
+          case 12:  // Stop (l) or start (h) blinking cursor
+            this.terminal_.setCursorBlink(set);
+            break;
+          case 25:  // Hide (l) or show (h) cursor
+            this.terminal_.setCursorVisible(set);
+            break;
+          case 45:  // Disable (l) or enable (h) reverse wraparound
+            this.terminal_.setReverseWraparound(set);
+            break;
+          case 67:  // Backspace is delete (h) or backspace (l)
+            this.setBackspaceSendsBackspace(set);
+            break;
+          case 1036:  // Meta sends (h) or doesn't send (l) escape
+            this.setMetaSendsEscape(set);
+            break;
+          case 1039:  // Alt sends (h) or doesn't send (l) escape
+            this.setAltSendsEscape(set);
+            break;
+          case 1049:  // Switch to/from alternate, save/restore cursor
+            this.terminal_.setAlternateMode(set);
+            break;
+          default:
+            console.log('Unimplemented l/h command: ' +
+                        (query ? '?' : '') + args[0]);
+            break;
+        }
+
+      } else {
+        switch (args[0]) {
+          case 4:  // Replace (l) or insert (h) mode
+            this.terminal_.setInsertMode(set);
+            break;
+          case 20:
+            // Normal linefeed (l), \n means move down only
+            // Automatic linefeed (h), \n means \n\r
+            this.terminal_.setAutoLinefeed(set);
+            break;
+          default:
+            console.log('Unimplemented l/h command: ' +
+                        (query ? '?' : '') + args[0]);
+            break;
+        }
+      }
+      break;
+
+    case 'r':
+      if (query) {
+        // Restore DEC private mode values
+        // TODO(maccarro): Implement this
+      } else {
+        // Set scroll region
+        var scrollTop = args[0] || null;
+        var scrollBottom = args[1] || null;
+        this.terminal_.setScrollRegion(scrollTop, scrollBottom);
+      }
+      break;
+
+    default:
+      console.log('Unknown control: ' + seqCommand);
+      break;
+  }
+  return processed;
+};