Function readInput

static/js/codemirror/codemirror.js:1345–1377

(cm)

  // events that indicate IME taking place, but these are not widely
  // supported or compatible enough yet to rely on.)
  function readInput(cm) {
    var input = cm.display.input, prevInput = cm.display.prevInput, doc = cm.doc, sel = doc.sel;
    if (!cm.state.focused || hasSelection(input) || isReadOnly(cm)) return false;
    var text = input.value;
    if (text == prevInput && posEq(sel.from, sel.to)) return false;
    // IE enjoys randomly deselecting our input's text when
    // re-focusing. If the selection is gone but the cursor is at the
    // start of the input, that's probably what happened.
    if (ie && text && input.selectionStart === 0) {
      resetInput(cm, true);
      return false;
    }
    var withOp = !cm.curOp;
    if (withOp) startOperation(cm);
    sel.shift = false;
    var same = 0, l = Math.min(prevInput.length, text.length);
    while (same < l && prevInput[same] == text[same]) ++same;
    var from = sel.from, to = sel.to;
    if (same < prevInput.length)
      from = Pos(from.line, from.ch - (prevInput.length - same));
    else if (cm.state.overwrite && posEq(from, to) && !cm.state.pasteIncoming)
      to = Pos(to.line, Math.min(getLine(doc, to.line).text.length, to.ch + (text.length - same)));
    var updateInput = cm.curOp.updateInput;
    makeChange(cm.doc, {from: from, to: to, text: splitLines(text.slice(same)),
                        origin: cm.state.pasteIncoming ? "paste" : "+input"}, "end");
               
    cm.curOp.updateInput = updateInput;
    if (text.length > 1000) input.value = cm.display.prevInput = "";
    else cm.display.prevInput = text;
    if (withOp) endOperation(cm);
    cm.state.pasteIncoming = false;
    return true;
  }

  function resetInput(cm, user) {
    var minimal, selected, doc = cm.doc;