-cleaning up dirmetascan code, still failing for me

git-svn-id: https://gnunet.org/svn/gnunet@19502 140774ce-b5e7-0310-ab8b-a85725594a96

4 files changed, 492 insertions, 1106 deletions

diff --git a/src/fs/Makefile.am b/src/fs/Makefile.am
index c4dfec0cae..fe593b394f 100644
--- a/src/fs/Makefile.am
+++ b/src/fs/Makefile.am
@@ -36,6 +36,7 @@ libgnunetfs_la_SOURCES = \
   fs_misc.c \
   fs_namespace.c \
   fs_search.c \
+  fs_sharetree.c \
   fs_tree.c fs_tree.h \
   fs_unindex.c \
   fs_uri.c 
diff --git a/src/fs/fs_dirmetascan.c b/src/fs/fs_dirmetascan.c
index 11313d7503..4c995a72a6 100644
--- a/src/fs/fs_dirmetascan.c
+++ b/src/fs/fs_dirmetascan.c
@@ -18,862 +18,471 @@
      Boston, MA 02111-1307, USA.
 */
 
+/**
+ * @file fs/fs_dirmetascan.c
+ * @brief code to asynchronously build a 'struct GNUNET_FS_ShareTreeItem'
+ *        from an on-disk directory for publishing
+ * @author LRN
+ * @author Christian Grothoff
+ */
 #include "platform.h"
 #include "gnunet_fs_service.h"
 #include "gnunet_scheduler_lib.h"
 #include <pthread.h>
 
+
 /**
- * Entry for each unique keyword to track how often
- * it occured.  Contains the keyword and the counter.
+ * An opaque structure a pointer to which is returned to the
+ * caller to be used to control the scanner.
  */
-struct KeywordCounter
+struct GNUNET_FS_DirScanner
 {
 
   /**
-   * Keyword that was found.
-   */
-  const char *value;
-
-  /**
-   * How many files have this keyword?
-   */
-  unsigned int count;
-
-  /**
-   * This is a doubly-linked list
-   */
-  struct KeywordCounter *prev;
-
-  /**
-   * This is a doubly-linked list
+   * A thread object for the scanner thread.
    */
-  struct KeywordCounter *next;
-};
+#if WINDOWS
+  HANDLE thread;
+#else
+  pthread_t thread;
+#endif
 
-/**
- * Aggregate information we keep for meta data in each directory.
- */
-struct MetaCounter
-{
   /**
-   * The actual meta data.
+   * Expanded filename (as given by the scan initiator).
+   * The scanner thread stores a copy here, and frees it when it finishes.
    */
-  const char *data;
+  char *filename_expanded;
 
   /**
-   * Number of bytes in 'data'.
+   * List of libextractor plugins to use for extracting.
+   * Initialized when the scan starts, removed when it finishes.
    */
-  size_t data_size;
-
+  struct EXTRACTOR_PluginList *plugins;
+  
   /**
-   * Name of the plugin that provided that piece of metadata
+   * A pipe transfer signals to the scanner.
    */
-  const char *plugin_name;
+  struct GNUNET_DISK_PipeHandle *stop_pipe;
 
   /**
-   * Type of the data
+   * A pipe end to read signals from.
    */
-  enum EXTRACTOR_MetaType type;
+  const struct GNUNET_DISK_FileHandle *stop_read;
 
   /**
-   * Format of the data
+   * A pipe end to read signals from.
    */
-  enum EXTRACTOR_MetaFormat format;
-
+  const struct GNUNET_DISK_FileHandle *stop_write;
+  
   /**
-   * MIME-type of the metadata itself
+   * The pipe that is used to read progress messages.  Only closed
+   * after the scanner thread is finished.
    */
-  const char *data_mime_type;
+  struct GNUNET_DISK_PipeHandle *progress_pipe;
 
   /**
-   * How many files have meta entries matching this value?
-   * (type and format do not have to match).
+   * The end of the pipe that is used to read progress messages.
    */
-  unsigned int count;
+  const struct GNUNET_DISK_FileHandle *progress_read;
 
   /**
-   * This is a doubly-linked list
+   * Handle of the pipe end into which the progress messages are written
+   * The initiator MUST keep it alive until the scanner thread is finished.
    */
-  struct MetaCounter *prev;
-
+  const struct GNUNET_DISK_FileHandle *progress_write;
+  
   /**
-   * This is a doubly-linked list
+   * The function that will be called every time there's a progress
+   * message.
    */
-  struct MetaCounter *next;
-};
-
-struct AddDirContext;
-
-/**
- * A structure used to hold a pointer to the tree item that is being
- * processed.
- * Needed to avoid changing the context for every recursive call.
- */
-struct AddDirStack
-{
+  GNUNET_FS_DirScannerProgressCallback progress_callback;
+  
   /**
-   * Context pointer
+   * A closure for progress_callback.
    */
-  struct AddDirContext *adc;
-
+  void *progress_callback_cls;
+  
   /**
-   * Parent directory
+   * A task for reading progress messages from the scanner.
    */
-  struct GNUNET_FS_ShareTreeItem *parent;
-};
+  GNUNET_SCHEDULER_TaskIdentifier progress_read_task;
 
-/**
- * Execution context for 'add_dir'
- * Owned by the initiator thread.
- */
-struct AddDirContext
-{
   /**
    * After the scan is finished, it will contain a pointer to the
    * top-level directory entry in the directory tree built by the
-   * scanner.
+   * scanner.  Must only be manipulated by the thread for the
+   * duration of the thread's runtime.
    */
   struct GNUNET_FS_ShareTreeItem *toplevel;
 
   /**
-   * Expanded filename (as given by the scan initiator).
-   * The scanner thread stores a copy here, and frees it when it finishes.
-   */
-  char *filename_expanded;
-
-  /**
-   * A pipe end to read signals from.
-   * Owned by the initiator thread.
-   */
-  const struct GNUNET_DISK_FileHandle *stop_read;
-
-  /**
    * 1 if the scanner should stop, 0 otherwise. Set in response
    * to communication errors or when the initiator wants the scanning
    * process to stop.
    */
-  char do_stop;
-
-  /**
-   * Handle of the pipe end into which the progress messages are written
-   * The pipe is owned by the initiator thread, and there's no way to
-   * close this end without having access to the pipe, so it won't
-   * be closed by the scanner thread.
-   * The initiator MUST keep it alive until the scanner thread is finished.
-   */
-  const struct GNUNET_DISK_FileHandle *progress_write;
+  int do_stop;
 
-
-  /**
-   * List of libextractor plugins to use for extracting.
-   * Initialized when the scan starts, removed when it finishes.
-   */
-  struct EXTRACTOR_PluginList *plugins;
 };
 
-/**
- * An opaque structure a pointer to which is returned to the
- * caller to be used to control the scanner.
- */
-struct GNUNET_FS_DirScanner
-{
-  /**
-   * A pipe end to read signals from.
-   * Owned by the initiator thread.
-   */
-  const struct GNUNET_DISK_FileHandle *stop_write;
-  
-  /**
-   * A pipe transfer signals to the scanner.
-   * Owned by the initiator thread.
-   */
-  struct GNUNET_DISK_PipeHandle *stop_pipe;
-
- /**
-  * A thread object for the scanner thread.
-  * Owned by the initiator thread.
-  */
-#if WINDOWS
-  HANDLE thread;
-#else
-  pthread_t thread;
-#endif
-
- /**
-  * A task for reading progress messages from the scanner.
-  */
-  GNUNET_SCHEDULER_TaskIdentifier progress_read_task;
-
- /**
-  * The end of the pipe that is used to read progress messages.
-  */
-  const struct GNUNET_DISK_FileHandle *progress_read;
-
- /**
-  * The pipe that is used to read progress messages.
-  * Owned (along with both of its ends) by the initiator thread.
-  * Only closed after the scanner thread is finished.
-  */
-  struct GNUNET_DISK_PipeHandle *progress_pipe;
-
- /**
-  * The function that will be called every time there's a progress
-  * message.
-  */
-  GNUNET_FS_DirScannerProgressCallback progress_callback;
 
- /**
-  * A closure for progress_callback.
-  */
-  void *cls;
-
- /**
-  * A pointer to the context of the scanner.
-  * Owned by the initiator thread.
-  * Initiator thread shouldn't touch it until the scanner thread
-  * is finished.
-  */
-  struct AddDirContext *adc;
-};
 
 /**
- * A structure that forms a singly-linked list that serves as a stack
- * for metadata-processing function.
+ * Abort the scan.
+ *
+ * @param ds directory scanner structure
  */
-struct ProcessMetadataStackItem
+void
+GNUNET_FS_directory_scan_abort (struct GNUNET_FS_DirScanner *ds)
 {
- /**
-  * A pointer to metadata-processing context.
-  * The same in every stack item.
-  */
-  struct GNUNET_FS_ProcessMetadataContext *ctx;
-
- /**
-  * This is a singly-linked list. A pointer to its end is kept, and
-  * this pointer is used to walk it backwards.
-  */
-  struct ProcessMetadataStackItem *parent;
+  static char c = 1;
 
-  /**
-   * Map from the hash over the keyword to an 'struct KeywordCounter *'
-   * counter that says how often this keyword was
-   * encountered in the current directory.
-   */
-  struct GNUNET_CONTAINER_MultiHashMap *keywordcounter;
+  /* signal shutdown to other thread */
+  (void) GNUNET_DISK_file_write (ds->stop_write, &c, 1);
+  GNUNET_DISK_pipe_close_end (ds->stop_pipe, GNUNET_DISK_PIPE_END_WRITE);
 
-  /**
-   * Map from the hash over the metadata to an 'struct MetaCounter *'
-   * counter that says how often this metadata was
-   * encountered in the current directory.
-   */
-  struct GNUNET_CONTAINER_MultiHashMap *metacounter;
-
-  /**
-   * Number of files in the current directory.
-   */
-  unsigned int dir_entry_count;
-
-  /**
-   * Keywords to exclude from using for KSK since they'll be associated
-   * with the parent as well.  NULL for nothing blocked.
-   */
-  struct GNUNET_FS_Uri *exclude_ksk;
+  /* stop reading from progress */
+  if (ds->progress_read_task != GNUNET_SCHEDULER_NO_TASK)
+  {
+    GNUNET_SCHEDULER_cancel (ds->progress_read_task);
+    ds->progress_read_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  GNUNET_DISK_pipe_close_end (ds->progress_pipe, GNUNET_DISK_PIPE_END_READ);
 
- /**
-  * A share tree item that is being processed.
-  */
-  struct GNUNET_FS_ShareTreeItem *item;
+  /* wait for other thread to terminate */
+#if WINDOWS
+  WaitForSingleObject (ds->thread, INFINITE);
+  CloseHandle (ds->thread);
+#else
+  pthread_join (ds->thread, NULL);
+  pthread_detach (ds->thread);
+#endif
 
- /**
-  * Set to GNUNET_YES to indicate that the directory pointer by 'item'
-  * was processed, and we should move on to the next.
-  * Otherwise the directory will be recursed into.
-  */
-  int end_directory;
+  /* free resources */
+  GNUNET_DISK_pipe_close (ds->stop_pipe);
+  GNUNET_DISK_pipe_close (ds->progress_pipe);
+  if (NULL != ds->toplevel)
+    GNUNET_FS_share_tree_free (ds->toplevel);
+  if (NULL != ds->plugins)
+    EXTRACTOR_plugin_remove_all (ds->plugins);
+  GNUNET_free (ds);
+}
 
-};
 
 /**
- * The structure to keep the state of metadata processing
+ * Obtain the result of the scan after the scan has signalled
+ * completion.  Must not be called prior to completion.  The 'ds' is
+ * freed as part of this call.
+ *
+ * @param ds directory scanner structure
+ * @return the results of the scan (a directory tree)
  */
-struct GNUNET_FS_ProcessMetadataContext
+struct GNUNET_FS_ShareTreeItem *
+GNUNET_FS_directory_scan_get_result (struct GNUNET_FS_DirScanner *ds)
 {
- /**
-  * The top of the stack.
-  */
-  struct ProcessMetadataStackItem *stack;
-
- /**
-  * Callback to invoke when processing is finished
-  */
-  GNUNET_SCHEDULER_Task cb;
-
- /**
-  * Closure for 'cb'
-  */
-  void *cls;
-
- /**
-  * Toplevel directory item of the tree to process.
-  */
-  struct GNUNET_FS_ShareTreeItem *toplevel;
-};
+  struct GNUNET_FS_ShareTreeItem *result;
 
-/**
- * Called every now and then by the scanner.
- * Checks the synchronization privitive.
- * Returns 1 if the scanner should stop, 0 otherwise.
- */
-static int
-should_stop (struct AddDirContext *adc)
-{
-  errno = 0;
-  char c;
-  if (GNUNET_DISK_file_read_non_blocking (adc->stop_read, &c, 1) == 1
-      || errno != EAGAIN)
-  {
-    adc->do_stop = 1;
-  }
-  return adc->do_stop;
+  /* check that we're actually done */
+  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == ds->progress_read_task);
+  /* preserve result */
+  result = ds->toplevel;
+  ds->toplevel = NULL; 
+  GNUNET_FS_directory_scan_abort (ds);
+  return result;
 }
 
+
 /**
- * Write progress message.
- * Format is:
- * "reason", "filename length", "filename", "directory flag"
- * If filename is NULL, filename is not written, and its length
- * is written as 0, and nothing else is written. It signals the initiator
- * thread that the scanner is finished, and that it can now join its thread.
+ * Write 'size' bytes from 'buf' into 'out'.
  *
- * Also checks if the initiator thread wants the scanner to stop,
- * Returns 1 to stop scanning (if the signal was received, or
- * if the pipe was broken somehow), 0 otherwise.
+ * @param in pipe to write to
+ * @param buf buffer with data to write
+ * @param size number of bytes to write
+ * @return GNUNET_OK on success, GNUNET_SYSERR on error
  */
 static int
-write_progress (struct AddDirContext *adc, const char *filename,
-    char is_directory, enum GNUNET_FS_DirScannerProgressUpdateReason reason)
+write_all (const struct GNUNET_DISK_FileHandle *out,
+	   const void *buf,
+	   size_t size)
 {
-  size_t filename_len;
+  const char *cbuf = buf;
+  size_t total;
   ssize_t wr;
-  size_t total_write;
-  if ((adc->do_stop || should_stop (adc)) && reason != GNUNET_FS_DIRSCANNER_ASKED_TO_STOP
-      && reason != GNUNET_FS_DIRSCANNER_FINISHED)
-    return 1;
-  total_write = 0;
-  wr = 1;
-  while ((wr > 0 || errno == EAGAIN) && total_write < sizeof (reason))
-  {
-    wr = GNUNET_DISK_file_write_blocking (adc->progress_write,
-      &((char *)&reason)[total_write], sizeof (reason) - total_write);
-    if (wr > 0)
-      total_write += wr;
-  }
-  if (sizeof (reason) != total_write)
-    return adc->do_stop = 1;
-  if (filename)
-    filename_len = strlen (filename) + 1;
-  else
-    filename_len = 0;
-  total_write = 0;
-  wr = 1;
-  while ((wr > 0 || errno == EAGAIN) && total_write < sizeof (size_t))
+
+  total = 0;
+  do
   {
-    wr = GNUNET_DISK_file_write_blocking (adc->progress_write,
-      &((char *)&filename_len)[total_write], sizeof (size_t) - total_write);
+    wr = GNUNET_DISK_file_write (out,
+				 &cbuf[total],
+				 size - total);
     if (wr > 0)
-      total_write += wr;
-  }
-  if (sizeof (size_t) != total_write)
-    return adc->do_stop = 1;
-  if (filename)
-  {
-    total_write = 0;
-    wr = 1;
-    while ((wr > 0 || errno == EAGAIN) && total_write < filename_len)
-    {
-      wr = GNUNET_DISK_file_write_blocking (adc->progress_write,
-        &((char *)filename)[total_write], filename_len - total_write);
-      if (wr > 0)
-        total_write += wr;
-    }
-    if (filename_len != total_write)
-      return adc->do_stop = 1;
-    total_write = 0;
-    wr = 1;
-    while ((wr > 0 || errno == EAGAIN) && total_write < sizeof (char))
-    {
-      wr = GNUNET_DISK_file_write_blocking (adc->progress_write,
-        &((char *)&is_directory)[total_write], sizeof (char) - total_write);
-      if (wr > 0)
-        total_write += wr;
-    }
-    if (sizeof (char) != total_write)
-      return adc->do_stop = 1;
-  }
-  return 0;
+      total += wr;
+  } while ( (wr > 0) && (total < size) );
+  return (total == size) ? GNUNET_OK : GNUNET_SYSERR;
 }
 
-/**
- * Add the given keyword to the
- * keyword statistics tracker.
- *
- * @param cls closure (user-defined)
- * @param keyword the keyword to count
- * @param is_mandatory ignored
- * @return always GNUNET_OK
- */
-static int
-add_to_keyword_counter (void *cls, const char *keyword, int is_mandatory)
-{
-  struct GNUNET_CONTAINER_MultiHashMap *mcm = cls;
-  struct KeywordCounter *cnt, *first_cnt;
-  GNUNET_HashCode hc;
-  size_t klen;
-
-  klen = strlen (keyword) + 1;
-  GNUNET_CRYPTO_hash (keyword, klen - 1, &hc);
-  /* Since the map might contain multiple values per keyword, we only
-   * store one value, and attach all other to it, forming a linked list.
-   * Somewhat easier than retrieving multiple items via callback.
-   */
-  first_cnt = GNUNET_CONTAINER_multihashmap_get (mcm, &hc);
-  for (cnt = first_cnt; cnt && strcmp (cnt->value, keyword) != 0; cnt = cnt->next);
-  if (cnt == NULL)
-  {
-    cnt = GNUNET_malloc (sizeof (struct KeywordCounter) + klen);
-    cnt->value = (const char *) &cnt[1];
-    memcpy (&cnt[1], keyword, klen);
-    if (first_cnt != NULL)
-    {
-      if (first_cnt->prev != NULL)
-      {
-        first_cnt->prev->next = cnt;
-        cnt->prev = first_cnt->prev;
-      }
-      first_cnt->prev = cnt;
-      cnt->next = first_cnt;
-    }
-    else
-      GNUNET_CONTAINER_multihashmap_put (mcm, &hc, cnt,
-          GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
-  }
-  cnt->count++;
-  return GNUNET_OK;
-}
 
 /**
- * Type of a function that libextractor calls for each
- * meta data item found.
+ * Write progress message.
  *
- * @param cls the container multihashmap to update
- * @param plugin_name name of the plugin that produced this value;
- *        special values can be used (i.e. '&lt;zlib&gt;' for zlib being
- *        used in the main libextractor library and yielding
- *        meta data).
- * @param type libextractor-type describing the meta data
- * @param format basic format information about data
- * @param data_mime_type mime-type of data (not of the original file);
- *        can be NULL (if mime-type is not known)
- * @param data actual meta-data found
- * @param data_len number of bytes in data
- * @return GNUNET_OK to continue extracting / iterating
+ * @param ds
+ * @param filename name of the file to transmit, never NULL
+ * @param is_directory GNUNET_YES for directory, GNUNET_NO for file, GNUNET_SYSERR for neither
+ * @param reason reason for the progress call
+ * @return GNUNET_SYSERR to stop scanning (the pipe was broken somehow)
  */
 static int
-add_to_meta_counter (void *cls, const char *plugin_name,
-                enum EXTRACTOR_MetaType type, enum EXTRACTOR_MetaFormat format,
-                const char *data_mime_type, const char *data, size_t data_len)
-{
-  struct GNUNET_CONTAINER_MultiHashMap *map = cls;
-  GNUNET_HashCode key;
-  struct MetaCounter *cnt, *first_cnt;
-
-  GNUNET_CRYPTO_hash (data, data_len, &key);
-  first_cnt = GNUNET_CONTAINER_multihashmap_get (map, &key);
-  for (cnt = first_cnt; cnt
-      && cnt->data_size != data_len
-      && memcmp (cnt->data, data, cnt->data_size) != 0; cnt = cnt->next);
-  if (cnt == NULL)
-  {
-    cnt = GNUNET_malloc (sizeof (struct MetaCounter));
-    cnt->data = data;
-    cnt->data_size = data_len;
-    cnt->plugin_name = plugin_name;
-    cnt->type = type;
-    cnt->format = format;
-    cnt->data_mime_type = data_mime_type;
-
-    if (first_cnt != NULL)
-    {
-      if (first_cnt->prev != NULL)
-      {
-        first_cnt->prev->next = cnt;
-        cnt->prev = first_cnt->prev;
-      }
-      first_cnt->prev = cnt;
-      cnt->next = first_cnt;
-    }
-    else
-      GNUNET_CONTAINER_multihashmap_put (map, &key, cnt,
-          GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
-  }
-  cnt->count++;
-  return 0;
-}
-
-/**
- * Allocates a struct GNUNET_FS_ShareTreeItem and adds it to its parent.
- */
-static struct GNUNET_FS_ShareTreeItem *
-make_item (struct GNUNET_FS_ShareTreeItem *parent)
+write_progress (struct GNUNET_FS_DirScanner *ds,
+		const char *filename,
+		int is_directory, 
+		enum GNUNET_FS_DirScannerProgressUpdateReason reason)
 {
-  struct GNUNET_FS_ShareTreeItem *item;
-  item = GNUNET_malloc (sizeof (struct GNUNET_FS_ShareTreeItem));
-
-  item->parent = parent;
-  if (parent)
-    GNUNET_CONTAINER_DLL_insert (parent->children_head, parent->children_tail,
-        item);
-  return item;
+  size_t slen;
+
+  slen = strlen (filename) + 1;
+  if ( (GNUNET_OK !=
+	write_all (ds->progress_write,
+		   &reason,
+		   sizeof (reason))) ||
+       (GNUNET_OK !=
+	write_all (ds->progress_write,
+		   &slen,
+		   sizeof (slen))) ||
+       (GNUNET_OK !=
+	write_all (ds->progress_write,
+		   filename,
+		   slen)) ||
+       (GNUNET_OK !=
+	write_all (ds->progress_write,
+		   &is_directory,
+		   sizeof (is_directory))) )
+    return GNUNET_SYSERR;
+  return GNUNET_OK;
 }
 
-/**
- * Extract metadata from a file and add it to the share tree
- *
- * @param ads context to modify
- * @param filename name of the file to process
- */
-static void
-extract_file (struct AddDirStack *ads, const char *filename)
-{
-  struct GNUNET_FS_ShareTreeItem *item;
-  const char *short_fn;
-
-  item = make_item (ads->parent);
-
-  GNUNET_DISK_file_size (filename, &item->file_size, GNUNET_YES);
-  item->is_directory = GNUNET_NO;
-
-  item->meta = GNUNET_CONTAINER_meta_data_create ();
-  GNUNET_FS_meta_data_extract_from_file (item->meta, filename,
-      ads->adc->plugins);
-  GNUNET_CONTAINER_meta_data_delete (item->meta, EXTRACTOR_METATYPE_FILENAME,
-      NULL, 0);
-  short_fn = GNUNET_STRINGS_get_short_name (filename);
-
-  item->filename = GNUNET_strdup (filename);
-  item->short_filename = GNUNET_strdup (short_fn);
-
-  GNUNET_CONTAINER_meta_data_insert (item->meta, "<libgnunetfs>",
-                                     EXTRACTOR_METATYPE_FILENAME,
-                                     EXTRACTOR_METAFORMAT_UTF8, "text/plain",
-                                     short_fn, strlen (short_fn) + 1);
-  if (ads->parent == NULL)
-  {
-    /* we're finished with the scan, make sure caller gets the top-level
-     * directory pointer
-     */
-    ads->adc->toplevel = item;
-  }
-}
 
 /**
- * Remove the keyword from the ksk URI.
- *
- * @param cls the ksk uri
- * @param keyword the word to remove
- * @param is_mandatory ignored
- * @return always GNUNET_OK
+ * Called every now and then by the scanner thread to check
+ * if we're being aborted.
+ * 
+ * @param ds scanner context
+ * @return GNUNET_OK to continue, GNUNET_SYSERR to stop
  */
 static int
-remove_keyword (void *cls, const char *keyword, int is_mandatory)
+test_thread_stop (struct GNUNET_FS_DirScanner *ds)
 {
-  struct GNUNET_FS_Uri *ksk = cls;
+  char c;
 
-  GNUNET_FS_uri_ksk_remove_keyword (ksk, keyword);
+  if ( (GNUNET_DISK_file_read_non_blocking (ds->stop_read, &c, 1) == 1) ||
+       (EAGAIN != errno) )
+    return GNUNET_SYSERR;
   return GNUNET_OK;
 }
 
+
 /**
- * Remove keywords from current directory's children, if they are
- * in the exluded keywords list of that directory.
+ * Function called to (recursively) add all of the files in the
+ * directory to the tree.  Called by the directory scanner to initiate
+ * the scan.  Does NOT yet add any metadata.
  *
- * @param cls the ksk uri
- * @param keyword the word to remove
- * @param is_mandatory ignored
- * @return always GNUNET_OK
+ * @param ds directory scanner context to use
+ * @param filename file or directory to scan
+ * @param dst where to store the resulting share tree item
+ * @return GNUNET_OK on success, GNUNET_SYSERR on error
  */
 static int
-remove_keywords (struct ProcessMetadataStackItem *stack, struct GNUNET_FS_ShareTreeItem *dir)
-{
-  struct GNUNET_FS_ShareTreeItem *item;
+preprocess_file (struct GNUNET_FS_DirScanner *ds,
+		 const char *filename,
+		 struct GNUNET_FS_ShareTreeItem **dst);
 
-  for (item = dir->children_head; item; item = item->next)
-  {
-    if (stack->exclude_ksk != NULL)
-      GNUNET_FS_uri_ksk_get_keywords (stack->exclude_ksk, &remove_keyword, item->ksk_uri);
-  }
-  return GNUNET_OK;
-}
 
 /**
- * Context passed to 'migrate_and_drop'.
+ * Closure for the 'scan_callback'
  */
-struct KeywordProcessContext
+struct RecursionContext
 {
   /**
-   * All the keywords we migrated to the parent.
+   * Global scanner context.
    */
-  struct GNUNET_FS_Uri *ksk;
-
-  /**
-   * How often does a keyword have to occur to be
-   * migrated to the parent?
-   */
-  unsigned int threshold;
-};
+  struct GNUNET_FS_DirScanner *ds;
 
-/**
- * Context passed to 'migrate_and_drop'.
- */
-struct MetaProcessContext
-{
   /**
-   * All the metadata we copy to the parent.
+   * Parent to add the files to.
    */
-  struct GNUNET_CONTAINER_MetaData *meta;
+  struct GNUNET_FS_ShareTreeItem *parent;
 
   /**
-   * How often does a metadata have to occur to be
-   * migrated to the parent?
+   * Flag to set to GNUNET_YES on serious errors.
    */
-  unsigned int threshold;
+  int stop;
 };
 
 
 /**
- * Move "frequent" keywords over to the
- * target ksk uri, free the counters.
+ * Function called by the directory iterator to (recursively) add all
+ * of the files in the directory to the tree.  Called by the directory
+ * scanner to initiate the scan.  Does NOT yet add any metadata.
  *
+ * @param cls the 'struct RecursionContext'
+ * @param filename file or directory to scan
+ * @return GNUNET_OK on success, GNUNET_SYSERR on error
  */
 static int
-migrate_and_drop (void *cls, const GNUNET_HashCode * key, void *value)
+scan_callback (void *cls,
+	       const char *filename)
 {
-  struct KeywordProcessContext *kpc = cls;
-  struct KeywordCounter *counter = value;
+  struct RecursionContext *rc = cls;
+  struct GNUNET_FS_ShareTreeItem *chld;
 
-  if (counter->count >= kpc->threshold && counter->count > 1)
+  if (GNUNET_OK !=
+      preprocess_file (rc->ds,
+		       filename,
+		       &chld))
   {
-    GNUNET_FS_uri_ksk_add_keyword (kpc->ksk, counter->value, GNUNET_NO);
+    rc->stop = GNUNET_YES;
+    return GNUNET_SYSERR;
   }
-  GNUNET_free (counter);
-  return GNUNET_YES;
+  chld->parent = rc->parent;
+  GNUNET_CONTAINER_DLL_insert (rc->parent->children_head,
+			       rc->parent->children_tail,
+			       chld);
+  return GNUNET_OK;
 }
-/**
- * Copy "frequent" metadata items over to the
- * target metadata container, free the counters.
- *
- */
-static int
-migrate_and_drop_metadata (void *cls, const GNUNET_HashCode * key, void *value)
-{
-  struct MetaProcessContext *mpc = cls;
-  struct MetaCounter *counter = value;
 
-  if (counter->count >= mpc->threshold && counter->count > 1)
-  {
-    GNUNET_CONTAINER_meta_data_insert (mpc->meta,
-                                   counter->plugin_name,
-                                   counter->type,
-                                   counter->format,
-                                   counter->data_mime_type, counter->data,
-                                   counter->data_size);
-  }
-  GNUNET_free (counter);
-  return GNUNET_YES;
-}
 
 /**
- * Go over the collected keywords from all entries in the
- * directory and push common keywords up one level (by
- * adding it to the returned struct). Do the same for metadata.
- * Destroys keywordcounter and metacoutner for current directory.
+ * Function called to (recursively) add all of the files in the
+ * directory to the tree.  Called by the directory scanner to initiate
+ * the scan.  Does NOT yet add any metadata.
  *
- * @param adc collection of child meta data
- * @param exclude_ksk pointer to where moveable keywords will be stored
- * @param copy_meta pointer to where copyable metadata will be stored
- */
-static void
-process_keywords_and_metadata (struct ProcessMetadataStackItem *stack,
-    struct GNUNET_FS_Uri **exclude_ksk,
-    struct GNUNET_CONTAINER_MetaData **copy_meta)
-{
-  struct KeywordProcessContext kpc;
-  struct MetaProcessContext mpc;
-  struct GNUNET_CONTAINER_MetaData *tmp;
-
-  /* Surprisingly, it's impossible to create a ksk with 0 keywords directly.
-   * But we can create one from an empty metadata set
-   */
-  tmp = GNUNET_CONTAINER_meta_data_create ();
-  kpc.ksk = GNUNET_FS_uri_ksk_create_from_meta_data (tmp);
-  GNUNET_CONTAINER_meta_data_destroy (tmp);
-  mpc.meta = GNUNET_CONTAINER_meta_data_create ();
-
-  kpc.threshold = mpc.threshold = (stack->dir_entry_count + 1) / 2; /* 50% */
-
-  GNUNET_CONTAINER_multihashmap_iterate (stack->keywordcounter,
-      &migrate_and_drop, &kpc);
-  GNUNET_CONTAINER_multihashmap_iterate (stack->metacounter,
-      &migrate_and_drop_metadata, &mpc);
-
-  GNUNET_CONTAINER_multihashmap_destroy (stack->keywordcounter);
-  GNUNET_CONTAINER_multihashmap_destroy (stack->metacounter);
-  *exclude_ksk = kpc.ksk;
-  *copy_meta = mpc.meta;
-}
-
-/**
- * Function called by the directory iterator to
- * (recursively) add all of the files in the
- * directory to the tree.
- * Called by the directory scanner to initiate the
- * scan.
- * TODO: find a way to make it non-recursive.
- *
- * @param cls the 'struct AddDirStack *' we're in
+ * @param ds directory scanner context to use
  * @param filename file or directory to scan
+ * @param dst where to store the resulting share tree item
+ * @return GNUNET_OK on success, GNUNET_SYSERR on error
  */
 static int
-scan_directory (void *cls, const char *filename)
+preprocess_file (struct GNUNET_FS_DirScanner *ds,
+		 const char *filename,
+		 struct GNUNET_FS_ShareTreeItem **dst)
 {
-  struct AddDirStack *ads = cls, recurse_ads;
-  struct AddDirContext *adc = ads->adc;
-  struct stat sbuf;
   struct GNUNET_FS_ShareTreeItem *item;
-  const char *short_fn;
-  int do_stop = 0;
-
-  /* Wrap up fast */
-  if (adc->do_stop)
-    return GNUNET_SYSERR;
+  struct stat sbuf;
 
-  /* If the file doesn't exist (or is not statable for any other reason,
-   * skip it, and report it.
-   */
   if (0 != STAT (filename, &sbuf))
   {
-    (void) write_progress (adc, filename, S_ISDIR (sbuf.st_mode),
-			   GNUNET_FS_DIRSCANNER_DOES_NOT_EXIST);
+    /* If the file doesn't exist (or is not stat-able for any other reason)
+       skip it (but report it), but do continue. */
+    if (GNUNET_OK !=
+	write_progress (ds, filename, GNUNET_SYSERR,
+			GNUNET_FS_DIRSCANNER_DOES_NOT_EXIST))
+      return GNUNET_SYSERR;
     return GNUNET_OK;
   }
 
   /* Report the progress */
-  do_stop = write_progress (adc, filename, S_ISDIR (sbuf.st_mode),
-    GNUNET_FS_DIRSCANNER_NEW_FILE);
-  if (do_stop)
-  {
-    /* We were asked to stop, acknowledge that and return */
-    (void) write_progress (adc, filename, S_ISDIR (sbuf.st_mode),
-      GNUNET_FS_DIRSCANNER_ASKED_TO_STOP);
+  if (GNUNET_OK !=
+      write_progress (ds, 
+		      filename, 
+		      S_ISDIR (sbuf.st_mode) ? GNUNET_YES : GNUNET_NO,
+		      GNUNET_FS_DIRSCANNER_FILE_START))
     return GNUNET_SYSERR;
-  }
-
-  if (!S_ISDIR (sbuf.st_mode))
-    extract_file (ads, filename);
-  else
-  {
-    item = make_item (ads->parent);
-    item->meta = GNUNET_CONTAINER_meta_data_create ();
-
-    item->is_directory = GNUNET_YES;
-
-    recurse_ads.adc = adc;
-    recurse_ads.parent = item;
-
-    /* recurse into directory */
-    GNUNET_DISK_directory_scan (filename, &scan_directory, &recurse_ads);
-
-    short_fn = GNUNET_STRINGS_get_short_name (filename);
-
-    item->filename = GNUNET_strdup (filename);
-    item->short_filename = GNUNET_strdup (short_fn);
-
-    if (ads->parent == NULL)
+  item = GNUNET_malloc (sizeof (struct GNUNET_FS_ShareTreeItem));
+  item->meta = GNUNET_CONTAINER_meta_data_create ();
+  item->filename = GNUNET_strdup (filename);
+  item->short_filename = GNUNET_strdup (GNUNET_STRINGS_get_short_name (filename));
+  item->is_directory = (S_ISDIR (sbuf.st_mode)) ? GNUNET_YES : GNUNET_NO;
+  item->file_size = (uint64_t) sbuf.st_size;
+  if (item->is_directory)
+  {
+    struct RecursionContext rc;
+
+    rc.parent = item;
+    rc.ds = ds;
+    rc.stop = GNUNET_NO;
+    GNUNET_DISK_directory_scan (filename, 
+				&scan_callback, 
+				&rc);    
+    if ( (rc.stop == GNUNET_YES) ||
+	 (GNUNET_OK != 
+	  test_thread_stop (ds)) )
     {
-      /* we're finished with the scan, make sure caller gets the top-level
-       * directory pointer
-       */
-      adc->toplevel = item;
+      GNUNET_FS_share_tree_free (item);
+      return GNUNET_SYSERR;
     }
   }
-  return GNUNET_OK;
-}
-
-/**
- * Signals the scanner to finish the scan as fast as possible.
- * Does not block.
- * Can close the pipe if asked to, but that is only used by the
- * internal call to this function during cleanup. The client
- * must understand the consequences of closing the pipe too early.
- *
- * @param ds directory scanner structure
- * @param close_pipe GNUNET_YES to close
- */
-void
-GNUNET_FS_directory_scan_finish (struct GNUNET_FS_DirScanner *ds,
-    int close_pipe)
-{
-  char c = 1;
-  GNUNET_DISK_file_write (ds->stop_write, &c, 1);
-
-  if (close_pipe)
+  /* Report the progress */
+  if (GNUNET_OK !=
+      write_progress (ds, 
+		      filename, 
+		      S_ISDIR (sbuf.st_mode) ? GNUNET_YES : GNUNET_NO,
+		      GNUNET_FS_DIRSCANNER_SUBTREE_COUNTED))
   {
-    if (ds->progress_read_task != GNUNET_SCHEDULER_NO_TASK)
-    {
-      GNUNET_SCHEDULER_cancel (ds->progress_read_task);
-      ds->progress_read_task = GNUNET_SCHEDULER_NO_TASK;
-    }
-    GNUNET_DISK_pipe_close_end (ds->progress_pipe, GNUNET_DISK_PIPE_END_READ);
-    ds->progress_read = NULL;
+    GNUNET_FS_share_tree_free (item);
+    return GNUNET_SYSERR;
   }
+  *dst = item;
+  return GNUNET_OK;
 }
 
+
 /**
- * Signals the scanner thread to finish (in case it isn't finishing
- * already) and joins the scanner thread. Closes the pipes, frees the
- * scanner contexts (both of them), returns the results of the scan.
- * Results are valid (and have to be freed) even if the scanner had
- * an error or was rushed to finish prematurely.
- * Blocks until the scanner is finished.
+ * Extract metadata from files.
  *
- * @param ds directory scanner structure
- * @return the results of the scan (a directory tree)
+ * @param ds directory scanner context
+ * @param item entry we are processing
+ * @return GNUNET_OK on success, GNUNET_SYSERR on fatal errors
  */
-struct GNUNET_FS_ShareTreeItem *
-GNUNET_FS_directory_scan_cleanup (struct GNUNET_FS_DirScanner *ds)
-{
-  struct GNUNET_FS_ShareTreeItem *result;
-
-  GNUNET_FS_directory_scan_finish (ds, GNUNET_YES);
-#if WINDOWS
-  WaitForSingleObject (ds->thread, INFINITE);
-  CloseHandle (ds->thread);
-#else
-  pthread_join (ds->thread, NULL);
-  pthread_detach (ds->thread);
-#endif
+static int
+extract_files (struct GNUNET_FS_DirScanner *ds,
+	       struct GNUNET_FS_ShareTreeItem *item)
+{  
+  if (item->is_directory)
+  {
+    /* for directories, we simply only descent, no extraction, no
+       progress reporting */
+    struct GNUNET_FS_ShareTreeItem *pos;
+
+    for (pos = item->children_head; NULL != pos; pos = pos->next)
+      if (GNUNET_OK !=
+	  extract_files (ds, pos))
+	return GNUNET_SYSERR;
+    return GNUNET_OK;
+  }
+  
+  /* this is the expensive operation, *afterwards* we'll check for aborts */
+  GNUNET_FS_meta_data_extract_from_file (item->meta, 
+					 item->filename,
+					 ds->plugins);
+
+  /* having full filenames is too dangerous; always make sure we clean them up */
+  GNUNET_CONTAINER_meta_data_delete (item->meta, 
+				     EXTRACTOR_METATYPE_FILENAME,
+				     NULL, 0);
+  GNUNET_CONTAINER_meta_data_insert (item->meta, "<libgnunetfs>",
+                                     EXTRACTOR_METATYPE_FILENAME,
+                                     EXTRACTOR_METAFORMAT_UTF8, "text/plain",
+                                     item->short_filename, 
+				     strlen (item->short_filename) + 1);
+  /* check for abort */
+  if (GNUNET_OK != 
+      test_thread_stop (ds))
+    return GNUNET_SYSERR;
 
-  GNUNET_DISK_pipe_close (ds->stop_pipe);
-  GNUNET_DISK_pipe_close (ds->progress_pipe);
-  result = ds->adc->toplevel;
-  GNUNET_free (ds->adc);
-  GNUNET_free (ds);
-  return result;
+  /* Report the progress */
+  if (GNUNET_OK !=
+      write_progress (ds, 
+		      item->filename, 
+		      GNUNET_NO,
+		      GNUNET_FS_DIRSCANNER_EXTRACT_FINISHED))
+    return GNUNET_SYSERR;
+  return GNUNET_OK;
 }
 
+
 /**
  * The function from which the scanner thread starts
+ *
+ * @param cls the 'struct GNUNET_FS_DirScanner'
+ * @return 0/NULL
  */
 #if WINDOWS
 DWORD
@@ -882,19 +491,58 @@ static void *
 #endif
 run_directory_scan_thread (void *cls)
 {
-  struct AddDirContext *adc = cls;
-  struct AddDirStack ads;
-  ads.adc = adc;
-  ads.parent = NULL;
-  scan_directory (&ads, adc->filename_expanded);
-  GNUNET_free (adc->filename_expanded);
-  if (adc->plugins != NULL)
-    EXTRACTOR_plugin_remove_all (adc->plugins);
-  /* Tell the initiator that we're finished, it can now join the thread */
-  write_progress (adc, NULL, 0, GNUNET_FS_DIRSCANNER_FINISHED);
+  struct GNUNET_FS_DirScanner *ds = cls;
+
+  if (GNUNET_OK != preprocess_file (ds, 
+				    ds->filename_expanded, 
+				    &ds->toplevel))
+  {
+    (void) write_progress (ds, "", GNUNET_NO, GNUNET_FS_DIRSCANNER_INTERNAL_ERROR);
+    return 0;
+  }
+  if (GNUNET_OK !=
+      write_progress (ds, "", GNUNET_NO, GNUNET_FS_DIRSCANNER_ALL_COUNTED))
+    return 0;
+  if (GNUNET_OK !=
+      extract_files (ds, ds->toplevel))
+  {
+    (void) write_progress (ds, "", GNUNET_NO, GNUNET_FS_DIRSCANNER_INTERNAL_ERROR);
+    return 0;
+  }
+  (void) write_progress (ds, "", GNUNET_NO, GNUNET_FS_DIRSCANNER_FINISHED);
   return 0;
 }
 
+
+/**
+ * Read 'size' bytes from 'in' into 'buf'.
+ *
+ * @param in pipe to read from
+ * @param buf buffer to read to
+ * @param size number of bytes to read
+ * @return GNUNET_OK on success, GNUNET_SYSERR on error
+ */
+static int
+read_all (const struct GNUNET_DISK_FileHandle *in,
+	  char *buf,
+	  size_t size)
+{
+  size_t total;
+  ssize_t rd;
+
+  total = 0;
+  do
+  {
+    rd = GNUNET_DISK_file_read (in,
+				&buf[total],
+				size - total);
+    if (rd > 0)
+      total += rd;
+  } while ( (rd > 0) && (total < size) );
+  return (total == size) ? GNUNET_OK : GNUNET_SYSERR;
+}
+
+
 /**
  * Called every time there is data to read from the scanner.
  * Calls the scanner progress handler.
@@ -905,124 +553,69 @@ run_directory_scan_thread (void *cls)
 static void
 read_progress_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
-  struct GNUNET_FS_DirScanner *ds;
-  int end_it = 0;
+  struct GNUNET_FS_DirScanner *ds = cls;
   enum GNUNET_FS_DirScannerProgressUpdateReason reason;
-  ssize_t rd;
-  ssize_t total_read;
-
   size_t filename_len;
-  char is_directory;
+  int is_directory;
   char *filename;
 
-  ds = cls;
-
   ds->progress_read_task = GNUNET_SCHEDULER_NO_TASK;
-
-  if (!(tc->reason & GNUNET_SCHEDULER_REASON_READ_READY))
+  if (! (tc->reason & GNUNET_SCHEDULER_REASON_READ_READY))
   {
-    ds->progress_callback (ds->cls, ds, NULL, 0, GNUNET_FS_DIRSCANNER_SHUTDOWN);
+    ds->progress_read_task
+      = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL,
+					ds->progress_read, &read_progress_task,
+					ds);
     return;
   }
 
   /* Read one message. If message is malformed or can't be read, end the scanner */
-  total_read = rd = GNUNET_DISK_file_read (ds->progress_read, &reason, sizeof (reason));
-  while (rd > 0 && total_read < sizeof (reason))
-  {
-    rd = GNUNET_DISK_file_read (ds->progress_read,
-        &((char *) &reason)[total_read],
-        sizeof (reason) - total_read);
-    if (rd > 0)
-      total_read += rd;
-  }
-  if (total_read != sizeof (reason)
-      || reason <= GNUNET_FS_DIRSCANNER_FIRST
-      || reason >= GNUNET_FS_DIRSCANNER_LAST)
-  {
-    end_it = 1;
-    reason = GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR;
-  }
-
-  if (!end_it)
-  {
-    total_read = rd = GNUNET_DISK_file_read (ds->progress_read, &filename_len,
-        sizeof (size_t));
-    while (rd > 0 && total_read < sizeof (size_t))
-    {
-      rd = GNUNET_DISK_file_read (ds->progress_read,
-          &((char *) &filename_len)[total_read],
-          sizeof (size_t) - total_read);
-      if (rd > 0)
-        total_read += rd;
-    }
-    if (rd != sizeof (size_t))
-    {
-      end_it = 1;
-      reason = GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR;
-    }
-  }
-  if (!end_it)
-  {
-    if (filename_len == 0)
-      end_it = 1;
-    else if (filename_len > PATH_MAX)
-    {
-      end_it = 1;
-      reason = GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR;
-    }
-  }
-  if (!end_it)
-  {
-    filename = GNUNET_malloc (filename_len);
-    total_read = rd = GNUNET_DISK_file_read (ds->progress_read, filename,
-        filename_len);
-    while (rd > 0 && total_read < filename_len)
-    {
-      rd = GNUNET_DISK_file_read (ds->progress_read, &filename[total_read],
-          filename_len - total_read);
-      if (rd > 0)
-        total_read += rd;
-    }
-    if (rd != filename_len)
-    {
-      GNUNET_free (filename);
-      reason = GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR;
-      end_it = 1;
-    }
-  }
-  if (!end_it && filename_len > 0)
-  {
-    total_read = rd = GNUNET_DISK_file_read (ds->progress_read, &is_directory,
-        sizeof (char));
-    while (rd > 0 && total_read < sizeof (char))
-    {
-      rd = GNUNET_DISK_file_read (ds->progress_read, &(&is_directory)[total_read],
-          sizeof (char) - total_read);
-      if (rd > 0)
-        total_read += rd;
-    }
-    if (rd != sizeof (char))
-    {
-      GNUNET_free (filename);
-      reason = GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR;
-      end_it = 1;
-    }
-  }
-  if (!end_it)
-  {
-    end_it = ds->progress_callback (ds->cls, ds, (const char *) filename, is_directory, reason);
-    GNUNET_free (filename);
-    if (!end_it)
-    {
-      ds->progress_read_task = GNUNET_SCHEDULER_add_read_file (
-          GNUNET_TIME_UNIT_FOREVER_REL, ds->progress_read, &read_progress_task,
-          cls);
-    }
-  }
-  else
-  {
-    ds->progress_callback (ds->cls, ds, NULL, 0, reason);
+  filename = NULL;
+  if ( (GNUNET_OK !=
+	read_all (ds->progress_read,
+		  (char*) &reason,
+		  sizeof (reason))) ||
+       (reason < GNUNET_FS_DIRSCANNER_FILE_START) ||
+       (reason > GNUNET_FS_DIRSCANNER_INTERNAL_ERROR) ||
+       (GNUNET_OK !=
+	read_all (ds->progress_read,
+		  (char*) &filename_len,
+		  sizeof (size_t))) ||
+       (filename_len == 0) ||
+       (filename_len > PATH_MAX) ||
+       (GNUNET_OK !=
+	read_all (ds->progress_read,
+		  filename = GNUNET_malloc (filename_len),
+		  filename_len)) ||
+       (filename[filename_len-1] != '\0') ||
+       (GNUNET_OK !=
+	read_all (ds->progress_read,
+		  (char*) &is_directory,
+		  sizeof (is_directory))) )
+  {
+    /* IPC error, complain, signal client and stop reading
+       from the pipe */
+    GNUNET_break (0);
+    ds->progress_callback (ds->progress_callback_cls, ds,
+			   NULL, GNUNET_SYSERR, 
+			   GNUNET_FS_DIRSCANNER_INTERNAL_ERROR);
+    GNUNET_free_non_null (filename);
+    return;
   }
+  /* schedule task to keep reading (done here in case client calls
+     abort or something similar) */
+  ds->progress_read_task 
+    = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, 
+				      ds->progress_read, 
+				      &read_progress_task, ds);
+
+  /* read successfully, notify client about progress */
+  ds->progress_callback (ds->progress_callback_cls, 
+			 ds, 
+			 filename,
+			 is_directory, 
+			 reason);
+  GNUNET_free (filename);
 }
 
 
@@ -1033,275 +626,89 @@ read_progress_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  * @param GNUNET_YES to not to run libextractor on files (only build a tree)
  * @param ex if not NULL, must be a list of extra plugins for extractor
  * @param cb the callback to call when there are scanning progress messages
- * @param cls closure for 'cb'
+ * @param cb_cls closure for 'cb'
  * @return directory scanner object to be used for controlling the scanner
  */
 struct GNUNET_FS_DirScanner *
 GNUNET_FS_directory_scan_start (const char *filename,
-    int disable_extractor, const char *ex,
-    GNUNET_FS_DirScannerProgressCallback cb, void *cls)
+				int disable_extractor, const char *ex,
+				GNUNET_FS_DirScannerProgressCallback cb, 
+				void *cb_cls)
 {
   struct stat sbuf;
-  struct AddDirContext *adc;
   char *filename_expanded;
   struct GNUNET_FS_DirScanner *ds;
   struct GNUNET_DISK_PipeHandle *progress_pipe;
+  struct GNUNET_DISK_PipeHandle *stop_pipe;
   int ok;
 
-  GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-	      "Starting to scan directory `%s'\n",
-	      filename);
   if (0 != STAT (filename, &sbuf))
     return NULL;
-
-  /* scan_directory() is guaranteed to be given expanded filenames,
-   * so expand we will!
-   */
   filename_expanded = GNUNET_STRINGS_filename_expand (filename);
-  if (filename_expanded == NULL)
+  if (NULL == filename_expanded)
     return NULL;
-
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+	      "Starting to scan directory `%s'\n",
+	      filename_expanded);
   progress_pipe = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);
-  if (progress_pipe == NULL)
+  if (NULL == progress_pipe)
   {
     GNUNET_free (filename_expanded);
     return NULL;
   }
-
-  adc = GNUNET_malloc (sizeof (struct AddDirContext));
-
-  ds = GNUNET_malloc (sizeof (struct GNUNET_FS_DirScanner));
-
-  ds->adc = adc;
-
-  ds->stop_pipe = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);
-  if (ds->stop_pipe == NULL)
+  stop_pipe = GNUNET_DISK_pipe (GNUNET_NO, GNUNET_NO, GNUNET_NO, GNUNET_NO);
+  if (NULL == stop_pipe)
   {
-    GNUNET_free (adc);
-    GNUNET_free (ds);
-    GNUNET_free (filename_expanded);
     GNUNET_DISK_pipe_close (progress_pipe);
+    GNUNET_free (filename_expanded);
     return NULL;
   }
+  
+  ds = GNUNET_malloc (sizeof (struct GNUNET_FS_DirScanner));
+  ds->progress_callback = cb;
+  ds->progress_callback_cls = cb_cls;
+  ds->stop_pipe = stop_pipe;
   ds->stop_write = GNUNET_DISK_pipe_handle (ds->stop_pipe,
-      GNUNET_DISK_PIPE_END_WRITE);
-  adc->stop_read = GNUNET_DISK_pipe_handle (ds->stop_pipe,
-      GNUNET_DISK_PIPE_END_READ);
-
-  adc->plugins = NULL;
-  if (!disable_extractor)
+					    GNUNET_DISK_PIPE_END_WRITE);
+  ds->stop_read = GNUNET_DISK_pipe_handle (ds->stop_pipe,
+					   GNUNET_DISK_PIPE_END_READ);
+  ds->progress_pipe = progress_pipe;
+  ds->progress_write = GNUNET_DISK_pipe_handle (progress_pipe,
+						GNUNET_DISK_PIPE_END_WRITE);
+  ds->progress_read = GNUNET_DISK_pipe_handle (progress_pipe,
+					       GNUNET_DISK_PIPE_END_READ);
+  ds->filename_expanded = filename_expanded;
+  if (! disable_extractor)
   {
-    adc->plugins = EXTRACTOR_plugin_add_defaults (
-        EXTRACTOR_OPTION_DEFAULT_POLICY);
-    if (ex && strlen (ex) > 0)
-      adc->plugins = EXTRACTOR_plugin_add_config (adc->plugins, ex,
-          EXTRACTOR_OPTION_DEFAULT_POLICY);
+    ds->plugins = EXTRACTOR_plugin_add_defaults (EXTRACTOR_OPTION_DEFAULT_POLICY);
+    if ( (NULL != ex) && strlen (ex) > 0)
+      ds->plugins = EXTRACTOR_plugin_add_config (ds->plugins, ex,
+						 EXTRACTOR_OPTION_DEFAULT_POLICY);
   }
-
-  adc->filename_expanded = filename_expanded;
-  adc->progress_write = GNUNET_DISK_pipe_handle (progress_pipe,
-      GNUNET_DISK_PIPE_END_WRITE);
-
-
-  ds->progress_read = GNUNET_DISK_pipe_handle (progress_pipe,
-      GNUNET_DISK_PIPE_END_READ);
-
-  GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
-	      "Creating thread to scan directory `%s'\n",
-	      filename);
-
 #if WINDOWS
   ds->thread = CreateThread (NULL, 0,
-      (LPTHREAD_START_ROUTINE) &run_directory_scan_thread, (LPVOID) adc,
-      0, NULL);
-  ok = ds->thread != NULL;
+			     (LPTHREAD_START_ROUTINE) &run_directory_scan_thread, 
+			     (LPVOID) ds, 0, NULL);
+  ok = (ds->thread != NULL);
 #else
-  ok = !pthread_create (&ds->thread, NULL, &run_directory_scan_thread,
-      (void *) adc);
+  ok = (0 == pthread_create (&ds->thread, NULL, 
+			     &run_directory_scan_thread, ds));
 #endif
   if (!ok)
   {
-    GNUNET_free (adc);
+    EXTRACTOR_plugin_remove_all (ds->plugins);
     GNUNET_free (filename_expanded);
+    GNUNET_DISK_pipe_close (stop_pipe);
     GNUNET_DISK_pipe_close (progress_pipe);
     GNUNET_free (ds);
     return NULL;
   }
-
-  ds->progress_callback = cb;
-  ds->cls = cls;
-  ds->adc = adc;
-  ds->progress_pipe = progress_pipe;
-
-  ds->progress_read_task = GNUNET_SCHEDULER_add_read_file (
-      GNUNET_TIME_UNIT_FOREVER_REL, ds->progress_read, &read_progress_task,
-      ds);
-
+  ds->progress_read_task 
+    = GNUNET_SCHEDULER_add_read_file (GNUNET_TIME_UNIT_FOREVER_REL, 
+				      ds->progress_read, 
+				      &read_progress_task, ds);
   return ds;
 }
 
-/**
- * Task that post-processes the share item tree.
- * This processing has to be done in the main thread, because
- * it requires access to libgcrypt's hashing functions, and
- * libgcrypt is not thread-safe without some special magic.
- *
- * @param cls top of the stack
- * @param tc task context
- */
-static void
-trim_share_tree_task (void *cls,
-  const struct GNUNET_SCHEDULER_TaskContext *tc)
-{
-  struct ProcessMetadataStackItem *stack = cls;
-  struct ProcessMetadataStackItem *next = stack;
-  /* FIXME: figure out what to do when tc says we're shutting down */
-
-  /* item == NULL means that we've just finished going over the children of
-   * current directory.
-   */
-  if (stack->item == NULL)
-  {
-    if (stack->parent->item != NULL)
-    {
-      /* end of a directory */
-      struct GNUNET_FS_Uri *ksk;
-
-      /* use keyword and metadata counters to create lists of keywords to move
-       * and metadata to copy.
-       */
-      process_keywords_and_metadata (stack, &stack->parent->exclude_ksk, &stack->parent->item->meta);
-
-      /* create keywords from metadata (copies all text-metadata as keywords,
-       * AND parses the directory name we've just added, producing even more
-       * keywords.
-       * then merge these keywords with the ones moved from children.
-       */
-      ksk = GNUNET_FS_uri_ksk_create_from_meta_data (stack->parent->item->meta);
-      stack->parent->item->ksk_uri = GNUNET_FS_uri_ksk_merge (ksk, stack->parent->exclude_ksk);
-      GNUNET_FS_uri_destroy (ksk);
-
-      /* remove moved keywords from children (complete the move) */
-      remove_keywords (stack->parent, stack->parent->item);
-      GNUNET_FS_uri_destroy (stack->parent->exclude_ksk);
-
-      /* go up the stack */
-      next = stack->parent;
-      GNUNET_free (stack);
-      next->end_directory = GNUNET_YES;
-    }
-    else
-    {
-      /* we've just finished processing the toplevel directory */
-      struct GNUNET_FS_ProcessMetadataContext *ctx = stack->ctx;
-      next = NULL;
-      GNUNET_SCHEDULER_add_continuation (ctx->cb, ctx->cls,
-          GNUNET_SCHEDULER_REASON_PREREQ_DONE);
-      GNUNET_free (stack->parent);
-      GNUNET_free (stack);
-      GNUNET_free (ctx);
-    }
-  }
-  else if (stack->item->is_directory
-      && !stack->end_directory
-      && stack->item->children_head != NULL)
-  {
-    /* recurse into subdirectory */
-    next = GNUNET_malloc (sizeof (struct ProcessMetadataStackItem));
-    next->ctx = stack->ctx;
-    next->item = stack->item->children_head;
-    next->keywordcounter = GNUNET_CONTAINER_multihashmap_create (1024);
-    next->metacounter = GNUNET_CONTAINER_multihashmap_create (1024);
-    next->dir_entry_count = 0;
-    next->parent = stack;
-  }
-  else
-  {
-    /* process a child entry (a file or a directory) and move to the next one*/
-    if (stack->item->is_directory)
-      stack->end_directory = GNUNET_NO;
-    if (stack->ctx->toplevel->is_directory)
-    {
-      stack->dir_entry_count++;
-      GNUNET_CONTAINER_meta_data_iterate (stack->item->meta, &add_to_meta_counter, stack->metacounter);
-
-      if (stack->item->is_directory)
-      {
-        char *user = getenv ("USER");
-        if ((user == NULL) || (0 != strncasecmp (user, stack->item->short_filename, strlen(user))))
-        {
-          /* only use filename if it doesn't match $USER */
-          GNUNET_CONTAINER_meta_data_insert (stack->item->meta, "<libgnunetfs>",
-					     EXTRACTOR_METATYPE_FILENAME,
-					     EXTRACTOR_METAFORMAT_UTF8,
-					     "text/plain", stack->item->short_filename,
-					     strlen (stack->item->short_filename) + 1);
-          GNUNET_CONTAINER_meta_data_insert (stack->item->meta, "<libgnunetfs>",
-					     EXTRACTOR_METATYPE_GNUNET_ORIGINAL_FILENAME,
-					     EXTRACTOR_METAFORMAT_UTF8,
-					     "text/plain", stack->item->short_filename,
-					     strlen (stack->item->short_filename) + 1);
-        }
-      }
-    }
-    stack->item->ksk_uri = GNUNET_FS_uri_ksk_create_from_meta_data (stack->item->meta);
-    if (stack->ctx->toplevel->is_directory)
-    {
-      GNUNET_FS_uri_ksk_get_keywords (stack->item->ksk_uri, &add_to_keyword_counter, stack->keywordcounter);
-    }
-    stack->item = stack->item->next;
-  }
-  /* Call this task again later, if there are more entries to process */
-  if (next)
-    GNUNET_SCHEDULER_add_continuation (&trim_share_tree_task, next,
-        GNUNET_SCHEDULER_REASON_PREREQ_DONE);
-}
-
-/**
- * Process a share item tree, moving frequent keywords up and
- * copying frequent metadata up.
- *
- * @param toplevel toplevel directory in the tree, returned by the scanner
- * @param cb called after processing is done
- * @param cls closure for 'cb'
- */
-struct GNUNET_FS_ProcessMetadataContext *
-GNUNET_FS_trim_share_tree (struct GNUNET_FS_ShareTreeItem *toplevel,
-    GNUNET_SCHEDULER_Task cb, void *cls)
-{
-  struct GNUNET_FS_ProcessMetadataContext *ret;
-
-  if (toplevel == NULL)
-  {
-    struct GNUNET_SCHEDULER_TaskContext tc;
-    tc.reason = GNUNET_SCHEDULER_REASON_PREREQ_DONE;
-    cb (cls, &tc);
-    return NULL;
-  }
-
-  ret = GNUNET_malloc (sizeof (struct GNUNET_FS_ProcessMetadataContext));
-  ret->toplevel = toplevel;
-  ret->stack = GNUNET_malloc (sizeof (struct ProcessMetadataStackItem));
-  ret->stack->ctx = ret;
-  ret->stack->item = toplevel;
 
-  if (ret->stack->ctx->toplevel->is_directory)
-  {
-    ret->stack->keywordcounter = GNUNET_CONTAINER_multihashmap_create (1024);
-    ret->stack->metacounter = GNUNET_CONTAINER_multihashmap_create (1024);
-  }
-
-  ret->stack->dir_entry_count = 0;
-  ret->stack->end_directory = GNUNET_NO;
-
-  /* dummy stack entry that tells us we're at the top of the stack */
-  ret->stack->parent = GNUNET_malloc (sizeof (struct ProcessMetadataStackItem));
-  ret->stack->parent->ctx = ret;
-
-  ret->cb = cb;
-  ret->cls = cls;
-
-  GNUNET_SCHEDULER_add_continuation (&trim_share_tree_task, ret->stack,
-    GNUNET_SCHEDULER_REASON_PREREQ_DONE);
-  return ret;
-}
+/* end of fs_dirmetascan.c */
diff --git a/src/fs/fs_sharetree.c b/src/fs/fs_sharetree.c
index 396415bc6a..6c9642b9bd 100644
--- a/src/fs/fs_sharetree.c
+++ b/src/fs/fs_sharetree.c
@@ -421,8 +421,10 @@ GNUNET_FS_share_tree_free (struct GNUNET_FS_ShareTreeItem *toplevel)
     GNUNET_CONTAINER_DLL_remove (toplevel->parent->children_head,
 				 toplevel->parent->children_tail,
 				 toplevel);
-  GNUNET_CONTAINER_meta_data_destroy (toplevel->meta);
-  GNUNET_FS_uri_destroy (toplevel->ksk_uri);
+  if (NULL != toplevel->meta)
+    GNUNET_CONTAINER_meta_data_destroy (toplevel->meta);
+  if (NULL != toplevel->ksk_uri)
+    GNUNET_FS_uri_destroy (toplevel->ksk_uri);
   GNUNET_free_non_null (toplevel->filename);
   GNUNET_free_non_null (toplevel->short_filename);
   GNUNET_free (toplevel);
diff --git a/src/fs/gnunet-publish.c b/src/fs/gnunet-publish.c
index 98f39b821b..33cba499eb 100644
--- a/src/fs/gnunet-publish.c
+++ b/src/fs/gnunet-publish.c
@@ -68,12 +68,8 @@ static GNUNET_SCHEDULER_TaskIdentifier kill_task;
 
 static struct GNUNET_FS_DirScanner *ds;
 
-static struct GNUNET_FS_ShareTreeItem * directory_scan_intermediary_result;
-
 static struct GNUNET_FS_ShareTreeItem * directory_scan_result;
 
-static struct GNUNET_FS_ProcessMetadataContext *pmc;
-
 static struct GNUNET_FS_Namespace *namespace;
 
 /**
@@ -378,21 +374,17 @@ get_file_information (struct GNUNET_FS_ShareTreeItem *item)
         item->ksk_uri, item->meta, !do_insert,
         &bo);
   }
-  GNUNET_CONTAINER_meta_data_destroy (item->meta);
-  GNUNET_FS_uri_destroy (item->ksk_uri);
-  GNUNET_free (item->short_filename);
-  GNUNET_free (item->filename);
-  GNUNET_free (item);
   return fi;
 }
 
+
 static void
-directory_trim_complete (void *cls,
-    const struct GNUNET_SCHEDULER_TaskContext *tc)
+directory_trim_complete ()
 {
   struct GNUNET_FS_FileInformation *fi;
-  directory_scan_result = directory_scan_intermediary_result;
+
   fi = get_file_information (directory_scan_result);
+  GNUNET_FS_share_tree_free (directory_scan_result);
   directory_scan_result = NULL;
   if (fi == NULL)
   {
@@ -425,7 +417,8 @@ directory_trim_complete (void *cls,
   }
 }
 
-static int
+
+static void
 directory_scan_cb (void *cls, struct GNUNET_FS_DirScanner *ds,
 		   const char *filename, 
 		   int is_directory,
@@ -433,64 +426,47 @@ directory_scan_cb (void *cls, struct GNUNET_FS_DirScanner *ds,
 {
   switch (reason)
   {
-    case GNUNET_FS_DIRSCANNER_NEW_FILE:
-      if (filename != NULL)
-      {
-        if (is_directory)
-          FPRINTF (stdout, _("Scanning directory `%s'.\n"), filename);
-        else
-          FPRINTF (stdout, _("Scanning file `%s'.\n"), filename);
-      }
+    case GNUNET_FS_DIRSCANNER_FILE_START:
+      if (is_directory)
+	FPRINTF (stdout, _("Scanning directory `%s'.\n"), filename);
+      else
+	FPRINTF (stdout, _("Scanning file `%s'.\n"), filename);      
       break;
-    case GNUNET_FS_DIRSCANNER_DOES_NOT_EXIST:
-      if (filename != NULL)
-      {
-        FPRINTF (stdout, 
-            _("Failed to scan `%s', because it does not exist.\n"),
-            filename);
-      }
+    case GNUNET_FS_DIRSCANNER_SUBTREE_COUNTED:
+      if (is_directory)
+	FPRINTF (stdout, _("Done scanning directory `%s'.\n"), filename);
       break;
-    case GNUNET_FS_DIRSCANNER_ASKED_TO_STOP:
-      if (filename != NULL)
-      {
-        FPRINTF (stdout, 
-            _("Scanner was about to scan `%s', but is now stopping.\n"),
-            filename);
-      }
-      else
-        FPRINTF (stdout, "%s", _("Scanner is stopping.\n"));
+    case GNUNET_FS_DIRSCANNER_ALL_COUNTED:
+      FPRINTF (stdout, "%s", _("Preprocessing complete.\n"));      
+      break;
+    case GNUNET_FS_DIRSCANNER_EXTRACT_FINISHED:
+      FPRINTF (stdout, _("Extracting meta data from file `%s' complete.\n"), filename);      
       break;
-    case GNUNET_FS_DIRSCANNER_SHUTDOWN:
-      FPRINTF (stdout, "%s", _("Client is shutting down.\n"));
+    case GNUNET_FS_DIRSCANNER_DOES_NOT_EXIST:
+      FPRINTF (stdout, 
+	       _("There was trouble processing file `%s', skipping it.\n"),
+	       filename);
       break;
     case GNUNET_FS_DIRSCANNER_FINISHED:
       FPRINTF (stdout, "%s", _("Scanner has finished.\n"));
+      directory_scan_result = GNUNET_FS_directory_scan_get_result (ds);
+      ds = NULL;
+      GNUNET_FS_share_tree_trim (directory_scan_result);
+      directory_trim_complete ();
       break;
-    case GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR:
-      FPRINTF (stdout, "%s", 
-          _("There was a failure communicating with the scanner.\n"));
+    case GNUNET_FS_DIRSCANNER_INTERNAL_ERROR:
+      FPRINTF (stdout, "%s", _("Internal error scanning directory.\n"));
+      GNUNET_FS_directory_scan_abort (ds);
+      ds = NULL;
+      if (namespace != NULL)
+	GNUNET_FS_namespace_delete (namespace, GNUNET_NO);
+      GNUNET_FS_stop (ctx);
+      ret = 1;
       break;
     default:
-      FPRINTF (stdout, _("Got unknown scanner update with filename `%s'.\n"),
-          filename);
+      GNUNET_assert (0);
       break;
   }
-  if ((filename == NULL && GNUNET_FS_DIRSCANNER_FINISHED)
-      || reason == GNUNET_FS_DIRSCANNER_PROTOCOL_ERROR
-      || reason == GNUNET_FS_DIRSCANNER_SHUTDOWN)
-  {
-    /* Any of this causes us to try to clean up the scanner */
-    directory_scan_intermediary_result = GNUNET_FS_directory_scan_cleanup (ds);
-    pmc = GNUNET_FS_trim_share_tree (directory_scan_intermediary_result,
-      &directory_trim_complete, NULL);
-
-    ds = NULL;
-    /* FIXME: change the tree processor to be able to free untrimmed trees
-     * right here instead of waiting for trimming to complete, if we need to
-     * cancel everything.
-     */
-  }
-  return 0;
 }