cms/acr/fs/FsContentProvider.java

   1 package org.argeo.cms.acr.fs;
   2
   3 import java.io.IOException;
   4 import java.nio.ByteBuffer;
   5 import java.nio.charset.StandardCharsets;
   6 import java.nio.file.Files;
   7 import java.nio.file.Path;
   8 import java.nio.file.attribute.UserDefinedFileAttributeView;
   9 import java.util.Iterator;
  10 import java.util.Map;
  11 import java.util.NavigableMap;
  12 import java.util.TreeMap;
  13 import java.util.stream.Collectors;
  14
  15 import org.argeo.api.acr.Content;
  16 import org.argeo.api.acr.ContentResourceException;
  17 import org.argeo.api.acr.CrName;
  18 import org.argeo.api.acr.NamespaceUtils;
  19 import org.argeo.api.acr.spi.ContentProvider;
  20 import org.argeo.api.acr.spi.ProvidedSession;
  21
  22 /** Access a file system as a {@link ContentProvider}. */
  23 public class FsContentProvider implements ContentProvider {
  24         final static String XMLNS_ = "xmlns:";
  25
  26         private final Path rootPath;
  27         private final boolean isRoot;
  28
  29         private NavigableMap<String, String> prefixes = new TreeMap<>();
  30
  31         public FsContentProvider(Path rootPath, boolean isRoot) {
  32                 this.rootPath = rootPath;
  33                 this.isRoot = isRoot;
  34                 initNamespaces();
  35         }
  36
  37         protected void initNamespaces() {
  38                 try {
  39                         UserDefinedFileAttributeView udfav = Files.getFileAttributeView(rootPath,
  40                                         UserDefinedFileAttributeView.class);
  41                         for (String name : udfav.list()) {
  42                                 if (name.startsWith(XMLNS_)) {
  43                                         ByteBuffer buf = ByteBuffer.allocate(udfav.size(name));
  44                                         udfav.read(name, buf);
  45                                         buf.flip();
  46                                         String namespace = StandardCharsets.UTF_8.decode(buf).toString();
  47                                         String prefix = name.substring(XMLNS_.length());
  48                                         prefixes.put(prefix, namespace);
  49                                 }
  50                         }
  51
  52                         // defaults
  53                         addDefaultNamespace(udfav, CrName.CR_DEFAULT_PREFIX, CrName.CR_NAMESPACE_URI);
  54                         addDefaultNamespace(udfav, "basic", CrName.CR_NAMESPACE_URI);
  55                         addDefaultNamespace(udfav, "owner", CrName.CR_NAMESPACE_URI);
  56                         addDefaultNamespace(udfav, "posix", CrName.CR_NAMESPACE_URI);
  57                 } catch (IOException e) {
  58                         throw new RuntimeException("Cannot read namespaces from " + rootPath, e);
  59                 }
  60
  61         }
  62
  63         protected void addDefaultNamespace(UserDefinedFileAttributeView udfav, String prefix, String namespace)
  64                         throws IOException {
  65                 if (!prefixes.containsKey(prefix)) {
  66                         ByteBuffer bb = ByteBuffer.wrap(namespace.getBytes(StandardCharsets.UTF_8));
  67                         int size = udfav.write(XMLNS_ + prefix, bb);
  68                         prefixes.put(prefix, namespace);
  69                 }
  70         }
  71
  72         boolean isRoot(Path path) {
  73                 try {
  74                         return isRoot && Files.isSameFile(rootPath, path);
  75                 } catch (IOException e) {
  76                         throw new ContentResourceException(e);
  77                 }
  78         }
  79
  80         @Override
  81         public Content get(ProvidedSession session, String mountPath, String relativePath) {
  82                 return new FsContent(session, this, rootPath.resolve(relativePath));
  83         }
  84
  85         /*
  86          * NAMESPACE CONTEXT
  87          */
  88
  89         @Override
  90         public String getNamespaceURI(String prefix) {
  91                 return NamespaceUtils.getNamespaceURI((p) -> prefixes.get(p), prefix);
  92         }
  93
  94         @Override
  95         public Iterator<String> getPrefixes(String namespaceURI) {
  96                 return NamespaceUtils.getPrefixes((ns) -> prefixes.entrySet().stream().filter(e -> e.getValue().equals(ns))
  97                                 .map(Map.Entry::getKey).collect(Collectors.toUnmodifiableSet()), namespaceURI);
  98         }
  99
 100 }