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gecko-dev/dom/media/webvtt/vtt.jsm

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42 KiB
JavaScript
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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
this.EXPORTED_SYMBOLS = ["WebVTT"];
/**
* Code below is vtt.js the JS WebVTT implementation.
* Current source code can be found at http://github.com/mozilla/vtt.js
*
* Code taken from commit b89bfd06cd788a68c67e03f44561afe833db0849
*/
/**
* Copyright 2013 vtt.js Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
var Cu = Components.utils;
Cu.import('resource://gre/modules/Services.jsm');
const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
const { XPCOMUtils } = require("resource://gre/modules/XPCOMUtils.jsm");
(function(global) {
var _objCreate = Object.create || (function() {
function F() {}
return function(o) {
if (arguments.length !== 1) {
throw new Error('Object.create shim only accepts one parameter.');
}
F.prototype = o;
return new F();
};
})();
// Creates a new ParserError object from an errorData object. The errorData
// object should have default code and message properties. The default message
// property can be overriden by passing in a message parameter.
// See ParsingError.Errors below for acceptable errors.
function ParsingError(errorData, message) {
this.name = "ParsingError";
this.code = errorData.code;
this.message = message || errorData.message;
}
ParsingError.prototype = _objCreate(Error.prototype);
ParsingError.prototype.constructor = ParsingError;
// ParsingError metadata for acceptable ParsingErrors.
ParsingError.Errors = {
BadSignature: {
code: 0,
message: "Malformed WebVTT signature."
},
BadTimeStamp: {
code: 1,
message: "Malformed time stamp."
}
};
// See spec, https://w3c.github.io/webvtt/#collect-a-webvtt-timestamp.
function collectTimeStamp(input) {
function computeSeconds(h, m, s, f) {
if (m > 59 || s > 59) {
return null;
}
// The attribute of the milli-seconds can only be three digits.
if (f.length !== 3) {
return null;
}
return (h | 0) * 3600 + (m | 0) * 60 + (s | 0) + (f | 0) / 1000;
}
var timestamp = input.match(/^(\d+:)?(\d{2}):(\d{2})\.(\d+)/);
if (!timestamp || timestamp.length !== 5) {
return null;
}
let hours = timestamp[1]? timestamp[1].replace(":", "") : 0;
let minutes = timestamp[2];
let seconds = timestamp[3];
let milliSeconds = timestamp[4];
return computeSeconds(hours, minutes, seconds, milliSeconds);
}
// A settings object holds key/value pairs and will ignore anything but the first
// assignment to a specific key.
function Settings() {
this.values = _objCreate(null);
}
Settings.prototype = {
set: function(k, v) {
if (v !== "") {
this.values[k] = v;
}
},
// Return the value for a key, or a default value.
// If 'defaultKey' is passed then 'dflt' is assumed to be an object with
// a number of possible default values as properties where 'defaultKey' is
// the key of the property that will be chosen; otherwise it's assumed to be
// a single value.
get: function(k, dflt, defaultKey) {
if (defaultKey) {
return this.has(k) ? this.values[k] : dflt[defaultKey];
}
return this.has(k) ? this.values[k] : dflt;
},
// Check whether we have a value for a key.
has: function(k) {
return k in this.values;
},
// Accept a setting if its one of the given alternatives.
alt: function(k, v, a) {
for (var n = 0; n < a.length; ++n) {
if (v === a[n]) {
this.set(k, v);
break;
}
}
},
// Accept a setting if its a valid digits value (int or float)
digitsValue: function(k, v) {
if (/^-0+(\.[0]*)?$/.test(v)) { // special case for -0.0
this.set(k, 0.0);
} else if (/^-?\d+(\.[\d]*)?$/.test(v)) {
this.set(k, parseFloat(v));
}
},
// Accept a setting if its a valid percentage.
percent: function(k, v) {
var m;
if ((m = v.match(/^([\d]{1,3})(\.[\d]*)?%$/))) {
v = parseFloat(v);
if (v >= 0 && v <= 100) {
this.set(k, v);
return true;
}
}
return false;
}
};
// Helper function to parse input into groups separated by 'groupDelim', and
// interprete each group as a key/value pair separated by 'keyValueDelim'.
function parseOptions(input, callback, keyValueDelim, groupDelim) {
var groups = groupDelim ? input.split(groupDelim) : [input];
for (var i in groups) {
if (typeof groups[i] !== "string") {
continue;
}
var kv = groups[i].split(keyValueDelim);
if (kv.length !== 2) {
continue;
}
var k = kv[0];
var v = kv[1];
callback(k, v);
}
}
function parseCue(input, cue, regionList) {
// Remember the original input if we need to throw an error.
var oInput = input;
// 4.1 WebVTT timestamp
function consumeTimeStamp() {
var ts = collectTimeStamp(input);
if (ts === null) {
throw new ParsingError(ParsingError.Errors.BadTimeStamp,
"Malformed timestamp: " + oInput);
}
// Remove time stamp from input.
input = input.replace(/^[^\s\uFFFDa-zA-Z-]+/, "");
return ts;
}
// 4.4.2 WebVTT cue settings
function consumeCueSettings(input, cue) {
var settings = new Settings();
parseOptions(input, function (k, v) {
switch (k) {
case "region":
// Find the last region we parsed with the same region id.
for (var i = regionList.length - 1; i >= 0; i--) {
if (regionList[i].id === v) {
settings.set(k, regionList[i].region);
break;
}
}
break;
case "vertical":
settings.alt(k, v, ["rl", "lr"]);
break;
case "line":
var vals = v.split(","),
vals0 = vals[0];
settings.digitsValue(k, vals0);
settings.percent(k, vals0) ? settings.set("snapToLines", false) : null;
settings.alt(k, vals0, ["auto"]);
if (vals.length === 2) {
settings.alt("lineAlign", vals[1], ["start", "center", "end"]);
}
break;
case "position":
vals = v.split(",");
settings.percent(k, vals[0]);
if (vals.length === 2) {
settings.alt("positionAlign", vals[1], ["line-left", "center", "line-right", "auto"]);
}
break;
case "size":
settings.percent(k, v);
break;
case "align":
settings.alt(k, v, ["start", "center", "end", "left", "right"]);
break;
}
}, /:/, /\s/);
// Apply default values for any missing fields.
cue.region = settings.get("region", null);
cue.vertical = settings.get("vertical", "");
cue.line = settings.get("line", "auto");
cue.lineAlign = settings.get("lineAlign", "start");
cue.snapToLines = settings.get("snapToLines", true);
cue.size = settings.get("size", 100);
cue.align = settings.get("align", "center");
cue.position = settings.get("position", "auto");
cue.positionAlign = settings.get("positionAlign", "center");
}
function skipWhitespace() {
input = input.replace(/^[ \f\n\r\t]+/, "");
}
// 4.1 WebVTT cue timings.
skipWhitespace();
cue.startTime = consumeTimeStamp(); // (1) collect cue start time
skipWhitespace();
if (input.substr(0, 3) !== "-->") { // (3) next characters must match "-->"
throw new ParsingError(ParsingError.Errors.BadTimeStamp,
"Malformed time stamp (time stamps must be separated by '-->'): " +
oInput);
}
input = input.substr(3);
skipWhitespace();
cue.endTime = consumeTimeStamp(); // (5) collect cue end time
// 4.1 WebVTT cue settings list.
skipWhitespace();
consumeCueSettings(input, cue);
}
function onlyContainsWhiteSpaces(input) {
return /^[ \f\n\r\t]+$/.test(input);
}
function containsTimeDirectionSymbol(input) {
return input.indexOf("-->") !== -1;
}
function maybeIsTimeStampFormat(input) {
return /^\s*(\d+:)?(\d{2}):(\d{2})\.(\d+)\s*-->\s*(\d+:)?(\d{2}):(\d{2})\.(\d+)\s*/.test(input);
}
var ESCAPE = {
"&amp;": "&",
"&lt;": "<",
"&gt;": ">",
"&lrm;": "\u200e",
"&rlm;": "\u200f",
"&nbsp;": "\u00a0"
};
var TAG_NAME = {
c: "span",
i: "i",
b: "b",
u: "u",
ruby: "ruby",
rt: "rt",
v: "span",
lang: "span"
};
var TAG_ANNOTATION = {
v: "title",
lang: "lang"
};
var NEEDS_PARENT = {
rt: "ruby"
};
// Parse content into a document fragment.
function parseContent(window, input, bReturnFrag) {
function nextToken() {
// Check for end-of-string.
if (!input) {
return null;
}
// Consume 'n' characters from the input.
function consume(result) {
input = input.substr(result.length);
return result;
}
var m = input.match(/^([^<]*)(<[^>]+>?)?/);
// The input doesn't contain a complete tag.
if (!m[0]) {
return null;
}
// If there is some text before the next tag, return it, otherwise return
// the tag.
return consume(m[1] ? m[1] : m[2]);
}
// Unescape a string 's'.
function unescape1(e) {
return ESCAPE[e];
}
function unescape(s) {
while ((m = s.match(/&(amp|lt|gt|lrm|rlm|nbsp);/))) {
s = s.replace(m[0], unescape1);
}
return s;
}
function shouldAdd(current, element) {
return !NEEDS_PARENT[element.localName] ||
NEEDS_PARENT[element.localName] === current.localName;
}
// Create an element for this tag.
function createElement(type, annotation) {
var tagName = TAG_NAME[type];
if (!tagName) {
return null;
}
var element = window.document.createElement(tagName);
element.localName = tagName;
var name = TAG_ANNOTATION[type];
if (name) {
element[name] = annotation ? annotation.trim() : "";
}
return element;
}
// https://w3c.github.io/webvtt/#webvtt-timestamp-object
// Return hhhhh:mm:ss.fff
function normalizedTimeStamp(secondsWithFrag) {
var totalsec = parseInt(secondsWithFrag, 10);
var hours = Math.floor(totalsec / 3600);
var minutes = Math.floor(totalsec % 3600 / 60);
var seconds = Math.floor(totalsec % 60);
if (hours < 10) {
hours = "0" + hours;
}
if (minutes < 10) {
minutes = "0" + minutes;
}
if (seconds < 10) {
seconds = "0" + seconds;
}
var f = secondsWithFrag.toString().split(".");
if (f[1]) {
f = f[1].slice(0, 3).padEnd(3, "0");
} else {
f = "000";
}
return hours + ':' + minutes + ':' + seconds + '.' + f;
}
var isFirefoxSupportPseudo = (/firefox/i.test(window.navigator.userAgent))
&& Services.prefs.getBoolPref("media.webvtt.pseudo.enabled");
var root;
if (bReturnFrag) {
root = window.document.createDocumentFragment();
} else if (isFirefoxSupportPseudo) {
root = window.document.createElement("div", {pseudo: "::cue"});
} else {
root = window.document.createElement("div");
}
var current = root,
t,
tagStack = [];
while ((t = nextToken()) !== null) {
if (t[0] === '<') {
if (t[1] === "/") {
// If the closing tag matches, move back up to the parent node.
if (tagStack.length &&
tagStack[tagStack.length - 1] === t.substr(2).replace(">", "")) {
tagStack.pop();
current = current.parentNode;
}
// Otherwise just ignore the end tag.
continue;
}
var ts = collectTimeStamp(t.substr(1, t.length - 1));
var node;
if (ts) {
// Timestamps are lead nodes as well.
node = window.document.createProcessingInstruction("timestamp", normalizedTimeStamp(ts));
current.appendChild(node);
continue;
}
var m = t.match(/^<([^.\s/0-9>]+)(\.[^\s\\>]+)?([^>\\]+)?(\\?)>?$/);
// If we can't parse the tag, skip to the next tag.
if (!m) {
continue;
}
// Try to construct an element, and ignore the tag if we couldn't.
node = createElement(m[1], m[3]);
if (!node) {
continue;
}
// Determine if the tag should be added based on the context of where it
// is placed in the cuetext.
if (!shouldAdd(current, node)) {
continue;
}
// Set the class list (as a list of classes, separated by space).
if (m[2]) {
node.className = m[2].substr(1).replace('.', ' ');
}
// Append the node to the current node, and enter the scope of the new
// node.
tagStack.push(m[1]);
current.appendChild(node);
current = node;
continue;
}
// Text nodes are leaf nodes.
current.appendChild(window.document.createTextNode(unescape(t)));
}
return root;
}
function StyleBox() {
}
// Apply styles to a div. If there is no div passed then it defaults to the
// div on 'this'.
StyleBox.prototype.applyStyles = function(styles, div) {
div = div || this.div;
for (var prop in styles) {
if (styles.hasOwnProperty(prop)) {
div.style[prop] = styles[prop];
}
}
};
StyleBox.prototype.formatStyle = function(val, unit) {
return val === 0 ? 0 : val + unit;
};
XPCOMUtils.defineLazyPreferenceGetter(StyleBox.prototype, "supportPseudo",
"media.webvtt.pseudo.enabled", false);
// Constructs the computed display state of the cue (a div). Places the div
// into the overlay which should be a block level element (usually a div).
function CueStyleBox(window, cue, styleOptions) {
var isIE8 = (typeof navigator !== "undefined") &&
(/MSIE\s8\.0/).test(navigator.userAgent);
var isFirefoxSupportPseudo = (/firefox/i.test(window.navigator.userAgent))
&& this.supportPseudo;
var color = "rgba(255, 255, 255, 1)";
var backgroundColor = "rgba(0, 0, 0, 0.8)";
if (isIE8) {
color = "rgb(255, 255, 255)";
backgroundColor = "rgb(0, 0, 0)";
}
StyleBox.call(this);
this.cue = cue;
// Parse our cue's text into a DOM tree rooted at 'cueDiv'. This div will
// have inline positioning and will function as the cue background box.
this.cueDiv = parseContent(window, cue.text, false);
var styles = {
color: color,
backgroundColor: backgroundColor,
display: "inline",
font: styleOptions.font,
whiteSpace: "pre-line",
};
if (isFirefoxSupportPseudo) {
delete styles.color;
delete styles.backgroundColor;
delete styles.font;
delete styles.whiteSpace;
}
if (!isIE8) {
styles.writingMode = cue.vertical === "" ? "horizontal-tb"
: cue.vertical === "lr" ? "vertical-lr"
: "vertical-rl";
styles.unicodeBidi = "plaintext";
}
this.applyStyles(styles, this.cueDiv);
// Create an absolutely positioned div that will be used to position the cue
// div.
styles = {
position: "absolute",
textAlign: cue.align,
font: styleOptions.font,
};
this.div = window.document.createElement("div");
this.applyStyles(styles);
this.div.appendChild(this.cueDiv);
// Calculate the distance from the reference edge of the viewport to the text
// position of the cue box. The reference edge will be resolved later when
// the box orientation styles are applied.
function convertCuePostionToPercentage(cuePosition) {
if (cuePosition === "auto") {
return 50;
}
return cuePosition;
}
var textPos = 0;
let postionPercentage = convertCuePostionToPercentage(cue.position);
switch (cue.computedPositionAlign) {
// TODO : modify these fomula to follow the spec, see bug 1277437.
case "line-left":
textPos = postionPercentage;
break;
case "center":
textPos = postionPercentage - (cue.size / 2);
break;
case "line-right":
textPos = postionPercentage - cue.size;
break;
}
// Horizontal box orientation; textPos is the distance from the left edge of the
// area to the left edge of the box and cue.size is the distance extending to
// the right from there.
if (cue.vertical === "") {
this.applyStyles({
left: this.formatStyle(textPos, "%"),
width: this.formatStyle(cue.size, "%")
});
// Vertical box orientation; textPos is the distance from the top edge of the
// area to the top edge of the box and cue.size is the height extending
// downwards from there.
} else {
this.applyStyles({
top: this.formatStyle(textPos, "%"),
height: this.formatStyle(cue.size, "%")
});
}
this.move = function(box) {
this.applyStyles({
top: this.formatStyle(box.top, "px"),
bottom: this.formatStyle(box.bottom, "px"),
left: this.formatStyle(box.left, "px"),
right: this.formatStyle(box.right, "px"),
height: this.formatStyle(box.height, "px"),
width: this.formatStyle(box.width, "px")
});
};
}
CueStyleBox.prototype = _objCreate(StyleBox.prototype);
CueStyleBox.prototype.constructor = CueStyleBox;
// Represents the co-ordinates of an Element in a way that we can easily
// compute things with such as if it overlaps or intersects with another Element.
// Can initialize it with either a StyleBox or another BoxPosition.
function BoxPosition(obj) {
var isIE8 = (typeof navigator !== "undefined") &&
(/MSIE\s8\.0/).test(navigator.userAgent);
// Either a BoxPosition was passed in and we need to copy it, or a StyleBox
// was passed in and we need to copy the results of 'getBoundingClientRect'
// as the object returned is readonly. All co-ordinate values are in reference
// to the viewport origin (top left).
var lh, height, width, top;
if (obj.div) {
height = obj.div.offsetHeight;
width = obj.div.offsetWidth;
top = obj.div.offsetTop;
var rects = (rects = obj.div.childNodes) && (rects = rects[0]) &&
rects.getClientRects && rects.getClientRects();
obj = obj.div.getBoundingClientRect();
// In certain cases the outter div will be slightly larger then the sum of
// the inner div's lines. This could be due to bold text, etc, on some platforms.
// In this case we should get the average line height and use that. This will
// result in the desired behaviour.
lh = rects ? Math.max((rects[0] && rects[0].height) || 0, obj.height / rects.length)
: 0;
}
this.left = obj.left;
this.right = obj.right;
this.top = obj.top || top;
this.height = obj.height || height;
this.bottom = obj.bottom || (top + (obj.height || height));
this.width = obj.width || width;
this.lineHeight = lh !== undefined ? lh : obj.lineHeight;
if (isIE8 && !this.lineHeight) {
this.lineHeight = 13;
}
}
// Move the box along a particular axis. Optionally pass in an amount to move
// the box. If no amount is passed then the default is the line height of the
// box.
BoxPosition.prototype.move = function(axis, toMove) {
toMove = toMove !== undefined ? toMove : this.lineHeight;
switch (axis) {
case "+x":
this.left += toMove;
this.right += toMove;
break;
case "-x":
this.left -= toMove;
this.right -= toMove;
break;
case "+y":
this.top += toMove;
this.bottom += toMove;
break;
case "-y":
this.top -= toMove;
this.bottom -= toMove;
break;
}
};
// Check if this box overlaps another box, b2.
BoxPosition.prototype.overlaps = function(b2) {
return this.left < b2.right &&
this.right > b2.left &&
this.top < b2.bottom &&
this.bottom > b2.top;
};
// Check if this box overlaps any other boxes in boxes.
BoxPosition.prototype.overlapsAny = function(boxes) {
for (var i = 0; i < boxes.length; i++) {
if (this.overlaps(boxes[i])) {
return true;
}
}
return false;
};
// Check if this box is within another box.
BoxPosition.prototype.within = function(container) {
return this.top >= container.top &&
this.bottom <= container.bottom &&
this.left >= container.left &&
this.right <= container.right;
};
// Check if this box is entirely within the container or it is overlapping
// on the edge opposite of the axis direction passed. For example, if "+x" is
// passed and the box is overlapping on the left edge of the container, then
// return true.
BoxPosition.prototype.overlapsOppositeAxis = function(container, axis) {
switch (axis) {
case "+x":
return this.left < container.left;
case "-x":
return this.right > container.right;
case "+y":
return this.top < container.top;
case "-y":
return this.bottom > container.bottom;
}
};
// Find the percentage of the area that this box is overlapping with another
// box.
BoxPosition.prototype.intersectPercentage = function(b2) {
var x = Math.max(0, Math.min(this.right, b2.right) - Math.max(this.left, b2.left)),
y = Math.max(0, Math.min(this.bottom, b2.bottom) - Math.max(this.top, b2.top)),
intersectArea = x * y;
return intersectArea / (this.height * this.width);
};
// Convert the positions from this box to CSS compatible positions using
// the reference container's positions. This has to be done because this
// box's positions are in reference to the viewport origin, whereas, CSS
// values are in referecne to their respective edges.
BoxPosition.prototype.toCSSCompatValues = function(reference) {
return {
top: this.top - reference.top,
bottom: reference.bottom - this.bottom,
left: this.left - reference.left,
right: reference.right - this.right,
height: this.height,
width: this.width
};
};
// Get an object that represents the box's position without anything extra.
// Can pass a StyleBox, HTMLElement, or another BoxPositon.
BoxPosition.getSimpleBoxPosition = function(obj) {
var height = obj.div ? obj.div.offsetHeight : obj.tagName ? obj.offsetHeight : 0;
var width = obj.div ? obj.div.offsetWidth : obj.tagName ? obj.offsetWidth : 0;
var top = obj.div ? obj.div.offsetTop : obj.tagName ? obj.offsetTop : 0;
obj = obj.div ? obj.div.getBoundingClientRect() :
obj.tagName ? obj.getBoundingClientRect() : obj;
var ret = {
left: obj.left,
right: obj.right,
top: obj.top || top,
height: obj.height || height,
bottom: obj.bottom || (top + (obj.height || height)),
width: obj.width || width
};
return ret;
};
// Move a StyleBox to its specified, or next best, position. The containerBox
// is the box that contains the StyleBox, such as a div. boxPositions are
// a list of other boxes that the styleBox can't overlap with.
function moveBoxToLinePosition(window, styleBox, containerBox, boxPositions) {
// Find the best position for a cue box, b, on the video. The axis parameter
// is a list of axis, the order of which, it will move the box along. For example:
// Passing ["+x", "-x"] will move the box first along the x axis in the positive
// direction. If it doesn't find a good position for it there it will then move
// it along the x axis in the negative direction.
function findBestPosition(b, axis) {
var bestPosition,
specifiedPosition = new BoxPosition(b),
percentage = 1; // Highest possible so the first thing we get is better.
for (var i = 0; i < axis.length; i++) {
while (b.overlapsOppositeAxis(containerBox, axis[i]) ||
(b.within(containerBox) && b.overlapsAny(boxPositions))) {
b.move(axis[i]);
}
// We found a spot where we aren't overlapping anything. This is our
// best position.
if (b.within(containerBox)) {
return b;
}
var p = b.intersectPercentage(containerBox);
// If we're outside the container box less then we were on our last try
// then remember this position as the best position.
if (percentage > p) {
bestPosition = new BoxPosition(b);
percentage = p;
}
// Reset the box position to the specified position.
b = new BoxPosition(specifiedPosition);
}
return bestPosition || specifiedPosition;
}
var boxPosition = new BoxPosition(styleBox),
cue = styleBox.cue,
linePos = cue.computedLine,
axis = [];
// If we have a line number to align the cue to.
if (cue.snapToLines) {
var size;
switch (cue.vertical) {
case "":
axis = [ "+y", "-y" ];
size = "height";
break;
case "rl":
axis = [ "+x", "-x" ];
size = "width";
break;
case "lr":
axis = [ "-x", "+x" ];
size = "width";
break;
}
var step = boxPosition.lineHeight,
position = step * Math.round(linePos),
maxPosition = containerBox[size] + step,
initialAxis = axis[0];
if (step == 0) {
return;
}
// If the specified intial position is greater then the max position then
// clamp the box to the amount of steps it would take for the box to
// reach the max position.
if (Math.abs(position) > maxPosition) {
position = position < 0 ? -1 : 1;
position *= Math.ceil(maxPosition / step) * step;
}
// If computed line position returns negative then line numbers are
// relative to the bottom of the video instead of the top. Therefore, we
// need to increase our initial position by the length or width of the
// video, depending on the writing direction, and reverse our axis directions.
if (linePos < 0) {
position += cue.vertical === "" ? containerBox.height : containerBox.width;
axis = axis.reverse();
}
// Move the box to the specified position. This may not be its best
// position.
boxPosition.move(initialAxis, position);
} else {
// If we have a percentage line value for the cue.
var calculatedPercentage = (boxPosition.lineHeight / containerBox.height) * 100;
switch (cue.lineAlign) {
case "center":
linePos -= (calculatedPercentage / 2);
break;
case "end":
linePos -= calculatedPercentage;
break;
}
// Apply initial line position to the cue box.
switch (cue.vertical) {
case "":
styleBox.applyStyles({
top: styleBox.formatStyle(linePos, "%")
});
break;
case "rl":
styleBox.applyStyles({
left: styleBox.formatStyle(linePos, "%")
});
break;
case "lr":
styleBox.applyStyles({
right: styleBox.formatStyle(linePos, "%")
});
break;
}
axis = [ "+y", "-x", "+x", "-y" ];
// Get the box position again after we've applied the specified positioning
// to it.
boxPosition = new BoxPosition(styleBox);
}
var bestPosition = findBestPosition(boxPosition, axis);
styleBox.move(bestPosition.toCSSCompatValues(containerBox));
}
function WebVTT() {
// Nothing
}
// Helper to allow strings to be decoded instead of the default binary utf8 data.
WebVTT.StringDecoder = function() {
return {
decode: function(data) {
if (!data) {
return "";
}
if (typeof data !== "string") {
throw new Error("Error - expected string data.");
}
return decodeURIComponent(encodeURIComponent(data));
}
};
};
WebVTT.convertCueToDOMTree = function(window, cuetext) {
if (!window) {
return null;
}
return parseContent(window, cuetext, true);
};
var FONT_SIZE_PERCENT = 0.05;
var FONT_STYLE = "sans-serif";
// Runs the processing model over the cues and regions passed to it.
// @param overlay A block level element (usually a div) that the computed cues
// and regions will be placed into.
// @param controls A Control bar element. Cues' position will be
// affected and repositioned according to it.
WebVTT.processCues = function(window, cues, overlay, controls) {
if (!window || !cues || !overlay) {
return null;
}
// Remove all previous children.
while (overlay.firstChild) {
overlay.firstChild.remove();
}
var controlBar;
var controlBarShown;
if (controls) {
controlBar = controls.ownerDocument.getAnonymousElementByAttribute(
controls, "anonid", "controlBar");
controlBarShown = controlBar ? !!controlBar.clientHeight : false;
}
var rootOfCues = window.document.createElement("div");
rootOfCues.style.position = "absolute";
rootOfCues.style.left = "0";
rootOfCues.style.right = "0";
rootOfCues.style.top = "0";
rootOfCues.style.bottom = "0";
overlay.appendChild(rootOfCues);
// Determine if we need to compute the display states of the cues. This could
// be the case if a cue's state has been changed since the last computation or
// if it has not been computed yet.
function shouldCompute(cues) {
if (overlay.lastControlBarShownStatus != controlBarShown) {
return true;
}
for (var i = 0; i < cues.length; i++) {
if (cues[i].hasBeenReset || !cues[i].displayState) {
return true;
}
}
return false;
}
// We don't need to recompute the cues' display states. Just reuse them.
if (!shouldCompute(cues)) {
for (var i = 0; i < cues.length; i++) {
rootOfCues.appendChild(cues[i].displayState);
}
overlay.lastControlBarShownStatus = controlBarShown;
return;
}
overlay.lastControlBarShownStatus = controlBarShown;
var boxPositions = [],
containerBox = BoxPosition.getSimpleBoxPosition(rootOfCues),
fontSize = Math.round(containerBox.height * FONT_SIZE_PERCENT * 100) / 100;
var styleOptions = {
font: fontSize + "px " + FONT_STYLE
};
(function() {
var styleBox, cue;
if (controlBarShown) {
// Add an empty output box that cover the same region as video control bar.
boxPositions.push(BoxPosition.getSimpleBoxPosition(controlBar));
}
for (var i = 0; i < cues.length; i++) {
cue = cues[i];
// Compute the intial position and styles of the cue div.
styleBox = new CueStyleBox(window, cue, styleOptions);
styleBox.cueDiv.style.setProperty("--cue-font-size", fontSize + "px");
rootOfCues.appendChild(styleBox.div);
// Move the cue div to it's correct line position.
moveBoxToLinePosition(window, styleBox, containerBox, boxPositions);
// Remember the computed div so that we don't have to recompute it later
// if we don't have too.
cue.displayState = styleBox.div;
boxPositions.push(BoxPosition.getSimpleBoxPosition(styleBox));
}
})();
};
WebVTT.Parser = function(window, decoder) {
this.window = window;
this.state = "INITIAL";
this.buffer = "";
this.decoder = decoder || new TextDecoder("utf8");
this.regionList = [];
};
WebVTT.Parser.prototype = {
// If the error is a ParsingError then report it to the consumer if
// possible. If it's not a ParsingError then throw it like normal.
reportOrThrowError: function(e) {
if (e instanceof ParsingError) {
this.onparsingerror && this.onparsingerror(e);
} else {
throw e;
}
},
parse: function (data) {
var self = this;
// If there is no data then we won't decode it, but will just try to parse
// whatever is in buffer already. This may occur in circumstances, for
// example when flush() is called.
if (data) {
// Try to decode the data that we received.
self.buffer += self.decoder.decode(data, {stream: true});
}
function collectNextLine() {
var buffer = self.buffer;
var pos = 0;
while (pos < buffer.length && buffer[pos] !== '\r' && buffer[pos] !== '\n') {
++pos;
}
var line = buffer.substr(0, pos);
// Advance the buffer early in case we fail below.
if (buffer[pos] === '\r') {
++pos;
}
if (buffer[pos] === '\n') {
++pos;
}
self.buffer = buffer.substr(pos);
// Spec defined replacement.
return line.replace(/[\u0000]/g, "\uFFFD");
}
function createCueIfNeeded() {
if (!self.cue) {
self.cue = new self.window.VTTCue(0, 0, "");
}
}
// Parsing cue identifier and the identifier should be unique.
// Return true if the input is a cue identifier.
function parseCueIdentifier(input) {
if (maybeIsTimeStampFormat(line)) {
self.state = "CUE";
return false;
}
createCueIfNeeded();
// TODO : ensure the cue identifier is unique among all cue identifiers.
self.cue.id = containsTimeDirectionSymbol(input) ? "" : input;
self.state = "CUE";
return true;
}
// Parsing the timestamp and cue settings.
// See spec, https://w3c.github.io/webvtt/#collect-webvtt-cue-timings-and-settings
function parseCueMayThrow(input) {
try {
createCueIfNeeded();
parseCue(input, self.cue, self.regionList);
self.state = "CUETEXT";
} catch (e) {
self.reportOrThrowError(e);
// In case of an error ignore rest of the cue.
self.cue = null;
self.state = "BADCUE";
}
}
// 3.4 WebVTT region and WebVTT region settings syntax
function parseRegion(input) {
var settings = new Settings();
parseOptions(input, function (k, v) {
switch (k) {
case "id":
settings.set(k, v);
break;
case "width":
settings.percent(k, v);
break;
case "lines":
settings.digitsValue(k, v);
break;
case "regionanchor":
case "viewportanchor":
var xy = v.split(',');
if (xy.length !== 2) {
break;
}
// We have to make sure both x and y parse, so use a temporary
// settings object here.
var anchor = new Settings();
anchor.percent("x", xy[0]);
anchor.percent("y", xy[1]);
if (!anchor.has("x") || !anchor.has("y")) {
break;
}
settings.set(k + "X", anchor.get("x"));
settings.set(k + "Y", anchor.get("y"));
break;
case "scroll":
settings.alt(k, v, ["up"]);
break;
}
}, /=/, /\s/);
// Create the region, using default values for any values that were not
// specified.
if (settings.has("id")) {
try {
var region = new self.window.VTTRegion();
region.width = settings.get("width", 100);
region.lines = settings.get("lines", 3);
region.regionAnchorX = settings.get("regionanchorX", 0);
region.regionAnchorY = settings.get("regionanchorY", 100);
region.viewportAnchorX = settings.get("viewportanchorX", 0);
region.viewportAnchorY = settings.get("viewportanchorY", 100);
region.scroll = settings.get("scroll", "");
// Register the region.
self.onregion && self.onregion(region);
// Remember the VTTRegion for later in case we parse any VTTCues that
// reference it.
self.regionList.push({
id: settings.get("id"),
region: region
});
} catch(e) {
dump("VTTRegion Error " + e + "\n");
var regionPref = Services.prefs.getBoolPref("media.webvtt.regions.enabled");
dump("regionPref " + regionPref + "\n");
}
}
}
// Parsing the WebVTT signature, it contains parsing algo step1 to step9.
// See spec, https://w3c.github.io/webvtt/#file-parsing
function parseSignatureMayThrow(input) {
let signature = collectNextLine();
if (!/^WEBVTT([ \t].*)?$/.test(signature)) {
throw new ParsingError(ParsingError.Errors.BadSignature);
} else {
self.state = "HEADER";
}
}
// Parsing the region and style information.
// See spec, https://w3c.github.io/webvtt/#collect-a-webvtt-block
//
// There are sereval things would appear in header,
// 1. Region or Style setting
// 2. Garbage (meaningless string)
// 3. Empty line
// 4. Cue's timestamp
// The case 4 happens when there is no line interval between the header
// and the cue blocks. In this case, we should preserve the line and
// return it for the next phase parsing.
function parseHeader() {
let line = null;
while (self.buffer && self.state === "HEADER") {
line = collectNextLine();
if (/^REGION|^STYLE/i.test(line)) {
parseOptions(line, function (k, v) {
switch (k.toUpperCase()) {
case "REGION":
parseRegion(v);
break;
case "STYLE":
// TODO : not supported yet.
break;
}
}, ":");
} else if (maybeIsTimeStampFormat(line)) {
self.state = "CUE";
break;
} else if (!line ||
onlyContainsWhiteSpaces(line) ||
containsTimeDirectionSymbol(line)) {
// empty line, whitespaces or string contains "-->"
break;
}
}
// End parsing header part and doesn't see the timestamp.
if (self.state === "HEADER") {
self.state = "ID";
line = null
}
return line;
}
// 5.1 WebVTT file parsing.
try {
if (self.state === "INITIAL") {
parseSignatureMayThrow();
}
var line;
if (self.state === "HEADER") {
line = parseHeader();
}
while (self.buffer) {
if (!line) {
// Since the data receiving is async, we need to wait until the
// buffer gets the full line.
if (!/\r\n|\n|\r/.test(self.buffer)) {
return this;
}
line = collectNextLine();
}
switch (self.state) {
case "ID":
// Ignore NOTE and line terminator
if (/^NOTE($|[ \t])/.test(line) || !line) {
break;
}
// If there is no cue identifier, keep the line and reuse this line
// in next iteration.
if (!parseCueIdentifier(line)) {
continue;
}
break;
case "CUE":
parseCueMayThrow(line);
break;
case "CUETEXT":
// Report the cue when (1) get an empty line (2) get the "-->""
if (!line || containsTimeDirectionSymbol(line)) {
// We are done parsing self cue.
self.oncue && self.oncue(self.cue);
self.cue = null;
self.state = "ID";
// Keep the line and reuse this line in next iteration.
continue;
}
if (self.cue.text) {
self.cue.text += "\n";
}
self.cue.text += line;
break;
case "BADCUE": // BADCUE
// 54-62 - Collect and discard the remaining cue.
if (!line) {
self.state = "ID";
}
break;
}
// The line was already parsed, empty it to ensure we can get the
// new line in next iteration.
line = null;
}
} catch (e) {
self.reportOrThrowError(e);
// If we are currently parsing a cue, report what we have.
if (self.state === "CUETEXT" && self.cue && self.oncue) {
self.oncue(self.cue);
}
self.cue = null;
// Enter BADWEBVTT state if header was not parsed correctly otherwise
// another exception occurred so enter BADCUE state.
self.state = self.state === "INITIAL" ? "BADWEBVTT" : "BADCUE";
}
return this;
},
flush: function () {
var self = this;
try {
// Finish decoding the stream.
self.buffer += self.decoder.decode();
// Synthesize the end of the current cue or region.
if (self.cue || self.state === "HEADER") {
self.buffer += "\n\n";
self.parse();
}
// If we've flushed, parsed, and we're still on the INITIAL state then
// that means we don't have enough of the stream to parse the first
// line.
if (self.state === "INITIAL") {
throw new ParsingError(ParsingError.Errors.BadSignature);
}
} catch(e) {
self.reportOrThrowError(e);
}
self.onflush && self.onflush();
return this;
}
};
global.WebVTT = WebVTT;
}(this));
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