NFolderZip.java

/* ========================================================================
 * PlantUML : a free UML diagram generator
 * ========================================================================
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 * (C) Copyright 2009-2024, Arnaud Roques
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package net.sourceforge.plantuml.nio;

import java.io.File;
import java.io.IOException;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Objects;

/**
 * A virtual folder representing a location inside a ZIP archive.
 *
 * <p>
 * Instances are immutable. Each instance points to the same ZIP file but to a
 * specific sub-path (which can be the root) inside that archive.
 */
public final class NFolderZip implements NFolder {

	private final File zipFile;
	/** Current path inside the ZIP (relative, no leading slash). */
	private final Path pathInsideZip;

	/** Creates a folder view of the ZIP root. */
	public NFolderZip(File zipFile) {
		this(zipFile, Paths.get(""));
	}

	private NFolderZip(File zipFile, Path currentPathInsideZip) {
		this.zipFile = Objects.requireNonNull(zipFile);
		this.pathInsideZip = Objects.requireNonNull(currentPathInsideZip).normalize();
	}

	@Override
	public InputFile getInputFile(Path nameOrPath) throws IOException {
		Objects.requireNonNull(nameOrPath);
		final String entry = toZipEntryName(nameOrPath);
		return new InputFileZip(zipFile, entry);
	}

	@Override
	public NFolder getSubfolder(Path nameOrPath) throws IOException {
		Objects.requireNonNull(nameOrPath);
		final String entry = toZipEntryName(nameOrPath);
		final Path next = entry.isEmpty() ? Paths.get("") : Paths.get(entry);
		return new NFolderZip(zipFile, next);
	}

	@Override
	public String toString() {
		final String prefix = pathInsideZip.toString().replace('\\', '/');
		return zipFile.getName() + "!" + prefix;
	}

	/**
	 * Resolves a path inside the ZIP and returns a forward-slash entry name without
	 * any leading slash (as typically stored in ZIPs).
	 */
	private String toZipEntryName(Path child) {
		final Path resolved = child.isAbsolute() ? child.normalize() : pathInsideZip.resolve(child).normalize();
		String s = resolved.toString().replace('\\', '/');
		while (s.startsWith("/"))
			s = s.substring(1);

		return s;
	}

}