package nl.siegmann.epublib.epub;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import net.sf.jazzlib.ZipEntry;
import net.sf.jazzlib.ZipException;
import net.sf.jazzlib.ZipFile;
import net.sf.jazzlib.ZipInputStream;
import nl.siegmann.epublib.domain.LazyResource;
import nl.siegmann.epublib.domain.MediaType;
import nl.siegmann.epublib.domain.Resource;
import nl.siegmann.epublib.domain.Resources;
import nl.siegmann.epublib.service.MediatypeService;
import nl.siegmann.epublib.util.CollectionUtil;
import nl.siegmann.epublib.util.ResourceUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Loads Resources from inputStreams, ZipFiles, etc
*
* @author paul
*
*/
public class ResourcesLoader {
private static final Logger LOG = LoggerFactory.getLogger(ResourcesLoader.class);
private static final ZipEntry ERROR_ZIP_ENTRY = new ZipEntry("<error>");
/**
* Loads the entries of the zipFile as resources.
*
* The MediaTypes that are in the lazyLoadedTypes will not get their contents loaded, but are stored as references to
* entries into the ZipFile and are loaded on demand by the Resource system.
*
* @param zipFile
* @param defaultHtmlEncoding
* @param lazyLoadedTypes
* @return
* @throws IOException
*/
public static Resources loadResources(ZipFile zipFile, String defaultHtmlEncoding,
List<MediaType> lazyLoadedTypes) throws IOException {
Resources result = new Resources();
Enumeration<? extends ZipEntry> entries = zipFile.entries();
while( entries.hasMoreElements() ) {
ZipEntry zipEntry = entries.nextElement();
if(zipEntry == null || zipEntry.isDirectory()) {
continue;
}
String href = zipEntry.getName();
Resource resource;
if (shouldLoadLazy(href, lazyLoadedTypes)) {
resource = new LazyResource(zipFile.getName(), zipEntry.getSize(), href);
} else {
resource = ResourceUtil.createResource(zipEntry, zipFile.getInputStream(zipEntry));
}
if(resource.getMediaType() == MediatypeService.XHTML) {
resource.setInputEncoding(defaultHtmlEncoding);
}
result.add(resource);
}
return result;
}
/**
* Whether the given href will load a mediaType that is in the collection of lazilyLoadedMediaTypes.
*
* @param href
* @param lazilyLoadedMediaTypes
* @return Whether the given href will load a mediaType that is in the collection of lazilyLoadedMediaTypes.
*/
private static boolean shouldLoadLazy(String href, Collection<MediaType> lazilyLoadedMediaTypes) {
if (CollectionUtil.isEmpty(lazilyLoadedMediaTypes)) {
return false;
}
MediaType mediaType = MediatypeService.determineMediaType(href);
return lazilyLoadedMediaTypes.contains(mediaType);
}
public static Resources loadResources(InputStream in, String defaultHtmlEncoding) throws IOException {
return loadResources(new ZipInputStream(in), defaultHtmlEncoding);
}
/**
* Loads all entries from the ZipInputStream as Resources.
*
* Loads the contents of all ZipEntries into memory.
* Is fast, but may lead to memory problems when reading large books on devices with small amounts of memory.
*
* @param zipInputStream
* @param defaultHtmlEncoding
* @return
* @throws IOException
*/
public static Resources loadResources(ZipInputStream zipInputStream, String defaultHtmlEncoding) throws IOException {
Resources result = new Resources();
ZipEntry zipEntry;
do {
// get next valid zipEntry
zipEntry = getNextZipEntry(zipInputStream);
if((zipEntry == null) || (zipEntry == ERROR_ZIP_ENTRY) || zipEntry.isDirectory()) {
continue;
}
// store resource
Resource resource = ResourceUtil.createResource(zipEntry, zipInputStream);
if(resource.getMediaType() == MediatypeService.XHTML) {
resource.setInputEncoding(defaultHtmlEncoding);
}
result.add(resource);
} while(zipEntry != null);
return result;
}
private static ZipEntry getNextZipEntry(ZipInputStream zipInputStream) throws IOException {
ZipEntry result = ERROR_ZIP_ENTRY;
try {
result = zipInputStream.getNextEntry();
} catch(ZipException e) {
LOG.error(e.getMessage());
zipInputStream.closeEntry();
}
return result;
}
/**
* Loads all entries from the ZipInputStream as Resources.
*
* Loads the contents of all ZipEntries into memory.
* Is fast, but may lead to memory problems when reading large books on devices with small amounts of memory.
*
* @param in
* @param defaultHtmlEncoding
* @return
* @throws IOException
*/
public static Resources loadResources(ZipFile zipFile, String defaultHtmlEncoding) throws IOException {
return loadResources(zipFile, defaultHtmlEncoding, Collections.<MediaType>emptyList());
}
}