igir/dist/packages/zip/src/zipReader.js

🕹 A zero-setup ROM collection manager that sorts, filters, extracts or archives, patches, and reports on collections of any size on any OS.

import fs from "node:fs";
import ArchiveExtraDataRecord from "./archiveExtraDataRecord.js";
import CentralDirectoryFileHeader from "./centralDirectoryFileHeader.js";
import DataDescriptor from "./dataDescriptor.js";
import EndOfCentralDirectory from "./endOfCentralDirectory.js";
import LocalFileHeader from "./localFileHeader.js";
class ZipReader {
  zipFilePath;
  _centralDirectoryFileHeaders;
  _endOfCentralDirectoryRecord;
  constructor(zipFilePath) {
    this.zipFilePath = zipFilePath;
  }
  /**
   * Return all central directory file headers.
   */
  async centralDirectoryFileHeaders() {
    if (this._centralDirectoryFileHeaders !== void 0) {
      return this._centralDirectoryFileHeaders;
    }
    const fileHandle = await fs.promises.open(this.zipFilePath, "r");
    try {
      const eocd = await this.endOfCentralDirectoryRecordFromFileHandle(fileHandle);
      this._centralDirectoryFileHeaders = await CentralDirectoryFileHeader.centralDirectoryFileFromFileHandle(
        this.zipFilePath,
        fileHandle,
        eocd
      );
      return this._centralDirectoryFileHeaders;
    } finally {
      await fileHandle.close();
    }
  }
  /**
   * Return the archive extra data record that may appear between the last local file's data and the
   * start of the central directory, or undefined when there isn't one.
   */
  async archiveExtraDataRecord() {
    const fileHandle = await fs.promises.open(this.zipFilePath, "r");
    try {
      const endOfLocalFiles = await this.endOfLocalFiles(fileHandle);
      return await ArchiveExtraDataRecord.fromFileHandle(fileHandle, endOfLocalFiles);
    } finally {
      await fileHandle.close();
    }
  }
  /**
   * Return the byte position immediately after the last local file's data and optional data
   * descriptor.
   */
  async endOfLocalFiles(fileHandle) {
    const centralDirectoryFileHeaders = await this.centralDirectoryFileHeaders();
    if (centralDirectoryFileHeaders.length === 0) {
      return 0;
    }
    const lastCentralDirectoryFileHeader = centralDirectoryFileHeaders.reduce(
      (last, current) => current.localFileHeaderRelativeOffsetResolved() > last.localFileHeaderRelativeOffsetResolved() ? current : last
    );
    const localFileHeader = await LocalFileHeader.localFileHeaderFromFileHandle(
      lastCentralDirectoryFileHeader,
      fileHandle
    );
    const dataEnd = localFileHeader.getLocalFileDataRelativeOffset() + localFileHeader.compressedSizeResolved();
    if (!localFileHeader.hasDataDescriptor()) {
      return dataEnd;
    }
    const dataDescriptor = await DataDescriptor.fromFileHandle(
      fileHandle,
      dataEnd,
      localFileHeader.versionNeeded >= 45
    );
    return dataEnd + dataDescriptor.raw.length;
  }
  async assertValidMagicNumber(fileHandle) {
    const magicNumber = await this.readMagicNumber(fileHandle);
    if (
      // At least one file in the zip
      !magicNumber.equals(LocalFileHeader.LOCAL_FILE_HEADER_SIGNATURE) && // No files in the zip
      !magicNumber.equals(EndOfCentralDirectory.END_OF_CENTRAL_DIRECTORY_RECORD_SIGNATURE) && // The zip is spanned, and this ISN'T the first file
      !magicNumber.equals(DataDescriptor.DATA_DESCRIPTOR_SIGNATURE)
    ) {
      throw new Error(`unknown zip file magic number: ${magicNumber.toString("hex")}`);
    }
  }
  async readMagicNumber(fileHandle) {
    const buffer = Buffer.allocUnsafe(4);
    await fileHandle.read({ buffer, position: 0 });
    return buffer;
  }
  /**
   * Return the end of central directory record.
   */
  async endOfCentralDirectoryRecord() {
    if (this._endOfCentralDirectoryRecord !== void 0) {
      return this._endOfCentralDirectoryRecord;
    }
    const fileHandle = await fs.promises.open(this.zipFilePath, "r");
    try {
      return await this.endOfCentralDirectoryRecordFromFileHandle(fileHandle);
    } finally {
      await fileHandle.close();
    }
  }
  async endOfCentralDirectoryRecordFromFileHandle(fileHandle) {
    if (this._endOfCentralDirectoryRecord !== void 0) {
      return this._endOfCentralDirectoryRecord;
    }
    await this.assertValidMagicNumber(fileHandle);
    this._endOfCentralDirectoryRecord = await EndOfCentralDirectory.fromFileHandle(fileHandle);
    return this._endOfCentralDirectoryRecord;
  }
}
export {
  ZipReader as default
};
//# sourceMappingURL=zipReader.js.map