117 lines
3.7 KiB
JavaScript
117 lines
3.7 KiB
JavaScript
class EpubParser {
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constructor(filesList) {
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this.files = filesList;
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this.parser = new DOMParser();
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this.opfXml = this.getOPFXml();
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this.encoder = new TextEncoder();
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}
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getTotalByteLength() {
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let size = 0;
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for (let key of Object.keys(this.files)) {
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let file = this.files[key];
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if (file.name.endsWith("html")) {
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console.log(file.name + " " + file._data.uncompressedSize)
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size += file._data.uncompressedSize;
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}
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}
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return size;
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}
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/**
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* @param {string} filename name of the file in filelist
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* @return {string} string representation of decompressed bytes
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*/
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decompress(filename) {
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return pako.inflate(this.files[filename]._data.compressedContent, {raw: true, to: "string"});
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}
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getOPFXml() {
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let content = this.decompress("META-INF/container.xml");
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let xml = this.parser.parseFromString(content, "text/xml");
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let path = xml.getElementsByTagName("rootfile")[0].getAttribute("full-path");
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this.opfDir = path.split("/").slice(0, -1).join("/");
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return this.parser.parseFromString(this.decompress(path), "text/xml");
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}
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getSpine() {
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return Array.from(this.opfXml.getElementsByTagName("spine")[0].children).map(node => node.getAttribute("idref"));
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}
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/**
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resolves an idref in content.opf to its file
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*/
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resolveIDref(idref) {
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return this.opfXml.getElementById(idref).getAttribute("href");
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}
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/**
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* returns absolute path from path relative to content.opf
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* @param path
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*/
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absPath(path) {
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if (this.opfDir) {
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return [this.opfDir, path].join("/");
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} else {
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return path;
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}
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}
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/**
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returns the sum of the bytesize of all html files that are located before it in the spine
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@param {string} currentFile idref of the current file, also part of the CFI, e.g. here: #epubcfi(/6/2[titlepage]!/4/1:0) it would be "titlepage"
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*/
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getPreviousFilesSize(currentFile) {
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let bytesize = 0;
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for (let file of this.getSpine()) {
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if (file !== currentFile) {
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let filepath = this.absPath(this.resolveIDref(file));
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//ignore non text files
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if (filepath.endsWith("html")) {
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console.log(filepath + " " + bytesize)
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bytesize += this.files[filepath]._data.uncompressedSize;
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}
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} else {
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break;
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}
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}
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return bytesize;
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}
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cfiToXmlNode(file,cfi){
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}
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/**
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takes the node that the cfi points at and counts the bytes of all nodes before that
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*/
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getCurrentFileProgress(currentFile, CFI) {
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let size = 0
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let startnode = this.cfiToXmlNode(currentFile,CFI);
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let prev = startnode.previousElementSibling;
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while (prev !== null) {
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size += this.encoder.encode(prev.outerHTML).length;
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prev = prev.previousElementSibling;
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}
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let parent = startnode.parentElement;
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while (parent !== null) {
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let parentPrev = parent.previousElementSibling;
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while (parentPrev !== null) {
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size += this.encoder.encode(parentPrev.outerHTML).length;
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parentPrev = parentPrev.previousElementSibling;
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}
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parent=parent.parentElement;
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}
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return size;
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}
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getProgress(currentFile, CFI) {
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let percentage = this.getTotalByteLength() / (this.getPreviousFilesSize(currentFile) + this.getCurrentFileProgress(currentFile, CFI));
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if (percentage === Infinity) {
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return 0;
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} else {
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return percentage;
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}
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}
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}
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