From b18dfef6563d8224e97b666c96a1441f9b4a308e Mon Sep 17 00:00:00 2001 From: ansuz Date: Fri, 29 Jan 2016 12:27:29 +0100 Subject: [PATCH] sharejs textarea is used by realtime-input.js --- www/common/sharejs_textarea.js | 185 +++++++++++++++++++++++++++++++++ 1 file changed, 185 insertions(+) create mode 100644 www/common/sharejs_textarea.js diff --git a/www/common/sharejs_textarea.js b/www/common/sharejs_textarea.js new file mode 100644 index 000000000..3ad0655bd --- /dev/null +++ b/www/common/sharejs_textarea.js @@ -0,0 +1,185 @@ +define(function () { + +/** + * Licensed under the standard MIT license: + * + * Copyright 2011 Joseph Gentle. + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + * + * See: https://github.com/share/ShareJS/blob/master/LICENSE + */ + +/* This contains the textarea binding for ShareJS. This binding is really + * simple, and a bit slow on big documents (Its O(N). However, it requires no + * changes to the DOM and no heavy libraries like ace. It works for any kind of + * text input field. + * + * You probably want to use this binding for small fields on forms and such. + * For code editors or rich text editors or whatever, I recommend something + * heavier. + */ + + +/* applyChange creates the edits to convert oldval -> newval. + * + * This function should be called every time the text element is changed. + * Because changes are always localised, the diffing is quite easy. We simply + * scan in from the start and scan in from the end to isolate the edited range, + * then delete everything that was removed & add everything that was added. + * This wouldn't work for complex changes, but this function should be called + * on keystroke - so the edits will mostly just be single character changes. + * Sometimes they'll paste text over other text, but even then the diff + * generated by this algorithm is correct. + * + * This algorithm is O(N). I suspect you could speed it up somehow using regular expressions. + */ +var applyChange = function(ctx, oldval, newval) { + // Strings are immutable and have reference equality. I think this test is O(1), so its worth doing. + if (oldval === newval) return; + + var commonStart = 0; + while (oldval.charAt(commonStart) === newval.charAt(commonStart)) { + commonStart++; + } + + var commonEnd = 0; + while (oldval.charAt(oldval.length - 1 - commonEnd) === newval.charAt(newval.length - 1 - commonEnd) && + commonEnd + commonStart < oldval.length && commonEnd + commonStart < newval.length) { + commonEnd++; + } + + var bugz = { + commonStart:commonStart, + commonEnd:commonEnd, + oldvalLength: oldval.length, + newvalLength: newval.length + }; + if (oldval.length !== commonStart + commonEnd) { + ctx.localChange && ctx.localChange(true); + ctx.remove(commonStart, oldval.length - commonStart - commonEnd); + } + if (newval.length !== commonStart + commonEnd) { + ctx.localChange && ctx.localChange(true); + ctx.insert(commonStart, newval.slice(commonStart, newval.length - commonEnd)); + } +}; + +/** + * Fix issues with textarea content which is different per-browser. + */ +var cannonicalize = function (content) { + + return content.replace(/\r\n/g, '\n'); +}; + +// Attach a textarea to a document's editing context. +// +// The context is optional, and will be created from the document if its not +// specified. +var attachTextarea = function(elem, ctx) { + + // initial state will always fail the !== check in genop. + var content = {}; + + // Replace the content of the text area with newText, and transform the + // current cursor by the specified function. + var replaceText = function(newText, transformCursor) { + if (transformCursor) { + var newSelection = [transformCursor(elem.selectionStart), transformCursor(elem.selectionEnd)]; + } + + // Fixate the window's scroll while we set the element's value. Otherwise + // the browser scrolls to the element. + var scrollTop = elem.scrollTop; + elem.value = newText; + content = elem.value; // Not done on one line so the browser can do newline conversion. + if (elem.scrollTop !== scrollTop) elem.scrollTop = scrollTop; + + // Setting the selection moves the cursor. We'll just have to let your + // cursor drift if the element isn't active, though usually users don't + // care. + if (newSelection && window.document.activeElement === elem) { + elem.selectionStart = newSelection[0]; + elem.selectionEnd = newSelection[1]; + } + }; + + //replaceText(ctx.get()); + + + // *** remote -> local changes + + ctx.onRemove(function(pos, length) { + var transformCursor = function(cursor) { + // If the cursor is inside the deleted region, we only want to move back to the start + // of the region. Hence the Math.min. + return pos < cursor ? cursor - Math.min(length, cursor - pos) : cursor; + }; + replaceText(ctx.getUserDoc(), transformCursor); + }); + + ctx.onInsert(function(pos, text) { + var transformCursor = function(cursor) { + return pos < cursor ? cursor + text.length : cursor; + }; + replaceText(ctx.getUserDoc(), transformCursor); + }); + + + // *** local -> remote changes + + // This function generates operations from the changed content in the textarea. + var genOp = function() { + // In a timeout so the browser has time to propogate the event's changes to the DOM. + setTimeout(function() { var val = elem.value; + if (val !== content) { + applyChange(ctx, ctx.getUserDoc(), cannonicalize(val)); + } + }, 0); + }; + + var eventNames = ['textInput', 'keydown', 'keyup', 'select', 'cut', 'paste']; + for (var i = 0; i < eventNames.length; i++) { + var e = eventNames[i]; + if (elem.addEventListener) { + elem.addEventListener(e, genOp, false); + } else { + elem.attachEvent('on' + e, genOp); + } + } + + ctx.detach = function() { + for (var i = 0; i < eventNames.length; i++) { + var e = eventNames[i]; + if (elem.removeEventListener) { + elem.removeEventListener(e, genOp, false); + } else { + elem.detachEvent('on' + e, genOp); + } + } + }; + + ctx.bumpSharejs = genOp; + + return ctx; +}; + +return { attach: attachTextarea }; +});