1 files changed, 452 insertions, 0 deletions
diff --git a/src/fs/fs_sharetree.c b/src/fs/fs_sharetree.c
new file mode 100644
index 0000000..c929428
--- /dev/null
+++ b/src/fs/fs_sharetree.c
@@ -0,0 +1,452 @@
+/*
+     This file is part of GNUnet
+     (C) 2005-2012 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 2, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file fs/fs_sharetree.c
+ * @brief code to manipulate the 'struct GNUNET_FS_ShareTreeItem' tree
+ * @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.
+ */
+struct KeywordCounter
+{
+
+  /**
+   * This is a doubly-linked list
+   */
+  struct KeywordCounter *prev;
+
+  /**
+   * This is a doubly-linked list
+   */
+  struct KeywordCounter *next;
+
+  /**
+   * Keyword that was found.
+   */
+  const char *value;
+
+  /**
+   * How many files have this keyword?
+   */
+  unsigned int count;
+
+};
+
+
+/**
+ * Aggregate information we keep for meta data in each directory.
+ */
+struct MetaCounter
+{
+
+  /**
+   * This is a doubly-linked list
+   */
+  struct MetaCounter *prev;
+
+  /**
+   * This is a doubly-linked list
+   */
+  struct MetaCounter *next;
+
+  /**
+   * Name of the plugin that provided that piece of metadata
+   */
+  const char *plugin_name;
+
+  /**
+   * MIME-type of the metadata itself
+   */
+  const char *data_mime_type;
+
+  /**
+   * The actual meta data.
+   */
+  const char *data;
+
+  /**
+   * Number of bytes in 'data'.
+   */
+  size_t data_size;
+
+  /**
+   * Type of the data
+   */
+  enum EXTRACTOR_MetaType type;
+
+  /**
+   * Format of the data
+   */
+  enum EXTRACTOR_MetaFormat format;
+
+  /**
+   * How many files have meta entries matching this value?
+   * (type and format do not have to match).
+   */
+  unsigned int count;
+
+};
+
+
+/**
+ * A structure that forms a singly-linked list that serves as a stack
+ * for metadata-processing function.
+ */
+struct TrimContext
+{
+
+  /**
+   * 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;
+
+  /**
+   * 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;
+
+  /**
+   * Position we are currently manipulating.
+   */
+  struct GNUNET_FS_ShareTreeItem *pos;
+
+  /**
+   * Number of times an item has to be found to be moved to the parent.
+   */
+  unsigned int move_threshold;
+
+};
+
+
+/**
+ * Add the given keyword to the keyword statistics tracker.
+ *
+ * @param cls the multihashmap we store the keyword counters in
+ * @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;
+  GNUNET_HashCode hc;
+  size_t klen;
+
+  klen = strlen (keyword) + 1;
+  GNUNET_CRYPTO_hash (keyword, klen - 1, &hc);
+  cnt = GNUNET_CONTAINER_multihashmap_get (mcm, &hc);
+  if (cnt == NULL)
+  {
+    cnt = GNUNET_malloc (sizeof (struct KeywordCounter) + klen);
+    cnt->value = (const char *) &cnt[1];
+    memcpy (&cnt[1], keyword, klen);
+    GNUNET_assert (GNUNET_OK ==
+		   GNUNET_CONTAINER_multihashmap_put (mcm, 
+						      &hc, cnt,
+						      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  }
+  cnt->count++;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Function called on each meta data item.  Increments the
+ * respective counter.
+ *
+ * @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
+ */
+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;
+
+  GNUNET_CRYPTO_hash (data, data_len, &key);
+  cnt = GNUNET_CONTAINER_multihashmap_get (map, &key);
+  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;
+    GNUNET_assert (GNUNET_OK ==
+		   GNUNET_CONTAINER_multihashmap_put (map,
+						      &key, cnt,
+						      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  }
+  cnt->count++;
+  return 0;
+}
+
+
+/**
+ * Remove keywords above the threshold.
+ *
+ * @param cls the 'struct TrimContext' with the pos to remove the keywords from
+ * @param keyword the keyword to check
+ * @param is_mandatory ignored
+ * @return always GNUNET_OK
+ */
+static int
+remove_high_frequency_keywords (void *cls, const char *keyword, int is_mandatory)
+{
+  struct TrimContext *tc = cls;
+  struct KeywordCounter *counter;
+  GNUNET_HashCode hc;
+  size_t klen;
+
+  klen = strlen (keyword) + 1;
+  GNUNET_CRYPTO_hash (keyword, klen - 1, &hc);
+  counter = GNUNET_CONTAINER_multihashmap_get (tc->keywordcounter, &hc);
+  GNUNET_assert (NULL != counter);
+  if (counter->count < tc->move_threshold)
+    return GNUNET_OK;
+  GNUNET_FS_uri_ksk_remove_keyword (tc->pos->ksk_uri,
+				    counter->value);
+  return GNUNET_OK;
+}
+
+
+/**
+ * Move "frequent" keywords over to the target ksk uri, free the
+ * counters.
+ *
+ * @param cls the 'struct TrimContext'
+ * @param key key of the entry
+ * @param value the 'struct KeywordCounter'
+ * @return GNUNET_YES (always)
+ */
+static int
+migrate_and_drop_keywords (void *cls, const GNUNET_HashCode * key, void *value)
+{
+  struct TrimContext *tc = cls;
+  struct KeywordCounter *counter = value;
+
+  if (counter->count >= tc->move_threshold)
+  {
+    if (NULL == tc->pos->ksk_uri)
+      tc->pos->ksk_uri = GNUNET_FS_uri_ksk_create_from_args (1, &counter->value);
+    else
+      GNUNET_FS_uri_ksk_add_keyword (tc->pos->ksk_uri, counter->value, GNUNET_NO);
+  }
+  GNUNET_assert (GNUNET_YES ==
+		 GNUNET_CONTAINER_multihashmap_remove (tc->keywordcounter,
+						       key,
+						       counter));
+  GNUNET_free (counter);
+  return GNUNET_YES;
+}
+
+
+/**
+ * Copy "frequent" metadata items over to the
+ * target metadata container, free the counters.
+ *
+ * @param cls the 'struct TrimContext'
+ * @param key key of the entry
+ * @param value the 'struct KeywordCounter'
+ * @return GNUNET_YES (always)
+ */
+static int
+migrate_and_drop_metadata (void *cls, const GNUNET_HashCode * key, void *value)
+{
+  struct TrimContext *tc = cls;
+  struct MetaCounter *counter = value;
+
+  if (counter->count >= tc->move_threshold)
+  {
+    if (NULL == tc->pos->meta)
+      tc->pos->meta = GNUNET_CONTAINER_meta_data_create ();
+    GNUNET_CONTAINER_meta_data_insert (tc->pos->meta,
+				       counter->plugin_name,
+				       counter->type,
+				       counter->format,
+				       counter->data_mime_type, counter->data,
+				       counter->data_size); 
+  }
+  GNUNET_assert (GNUNET_YES ==
+		 GNUNET_CONTAINER_multihashmap_remove (tc->metacounter,
+						       key,
+						       counter));
+  GNUNET_free (counter);
+  return GNUNET_YES;
+}
+
+
+/**
+ * Process a share item tree, moving frequent keywords up and
+ * copying frequent metadata up.
+ *
+ * @param tc trim context with hash maps to use
+ * @param tree tree to trim
+ */
+static void
+share_tree_trim (struct TrimContext *tc,
+		 struct GNUNET_FS_ShareTreeItem *tree)
+{
+  struct GNUNET_FS_ShareTreeItem *pos;
+  unsigned int num_children;
+
+  /* first, trim all children */
+  num_children = 0;
+  for (pos = tree->children_head; NULL != pos; pos = pos->next)
+  {
+    share_tree_trim (tc, pos);
+    num_children++;
+  }
+
+  /* consider adding filename to directory meta data */
+  if (tree->is_directory == GNUNET_YES)
+  {
+    const char *user = getenv ("USER");
+    if ( (user == NULL) || 
+	 (0 != strncasecmp (user, tree->short_filename, strlen(user))))
+    {
+      /* only use filename if it doesn't match $USER */
+      if (NULL == tree->meta)
+	tree->meta = GNUNET_CONTAINER_meta_data_create ();
+      GNUNET_CONTAINER_meta_data_insert (tree->meta, "<libgnunetfs>",
+					 EXTRACTOR_METATYPE_GNUNET_ORIGINAL_FILENAME,
+					 EXTRACTOR_METAFORMAT_UTF8,
+					 "text/plain", tree->short_filename,
+					 strlen (tree->short_filename) + 1);
+    }
+  }
+
+  if (1 >= num_children)
+    return; /* nothing to trim */
+  
+  /* now, count keywords and meta data in children */
+  for (pos = tree->children_head; NULL != pos; pos = pos->next)
+  {
+    if (NULL != pos->meta)
+      GNUNET_CONTAINER_meta_data_iterate (pos->meta, &add_to_meta_counter, tc->metacounter);    
+    if (NULL != pos->ksk_uri)
+      GNUNET_FS_uri_ksk_get_keywords (pos->ksk_uri, &add_to_keyword_counter, tc->keywordcounter);
+  }
+
+  /* calculate threshold for moving keywords / meta data */
+  tc->move_threshold = 1 + (num_children / 2);
+
+  /* remove high-frequency keywords from children */
+  for (pos = tree->children_head; NULL != pos; pos = pos->next)
+  {
+    tc->pos = pos;
+    if (NULL != pos->ksk_uri)
+    {
+      struct GNUNET_FS_Uri *ksk_uri_copy = GNUNET_FS_uri_dup (pos->ksk_uri);
+      GNUNET_FS_uri_ksk_get_keywords (ksk_uri_copy, &remove_high_frequency_keywords, tc);
+      GNUNET_FS_uri_destroy (ksk_uri_copy);
+    }
+  }
+
+  /* add high-frequency meta data and keywords to parent */
+  tc->pos = tree;
+  GNUNET_CONTAINER_multihashmap_iterate (tc->keywordcounter, 
+					 &migrate_and_drop_keywords,
+					 tc);
+  GNUNET_CONTAINER_multihashmap_iterate (tc->metacounter, 
+					 &migrate_and_drop_metadata,
+					 tc);
+}
+
+
+/**
+ * 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
+ */
+void
+GNUNET_FS_share_tree_trim (struct GNUNET_FS_ShareTreeItem *toplevel)
+{
+  struct TrimContext tc;
+
+  if (toplevel == NULL)
+    return;  
+  tc.keywordcounter = GNUNET_CONTAINER_multihashmap_create (1024);
+  tc.metacounter = GNUNET_CONTAINER_multihashmap_create (1024);
+  share_tree_trim (&tc, toplevel);
+  GNUNET_CONTAINER_multihashmap_destroy (tc.keywordcounter);
+  GNUNET_CONTAINER_multihashmap_destroy (tc.metacounter);
+}
+
+
+/**
+ * Release memory of a share item tree.
+ *
+ * @param toplevel toplevel of the tree to be freed
+ */
+void
+GNUNET_FS_share_tree_free (struct GNUNET_FS_ShareTreeItem *toplevel)
+{
+  struct GNUNET_FS_ShareTreeItem *pos;
+
+  while (NULL != (pos = toplevel->children_head))
+    GNUNET_FS_share_tree_free (pos);
+  if (NULL != toplevel->parent)
+    GNUNET_CONTAINER_DLL_remove (toplevel->parent->children_head,
+				 toplevel->parent->children_tail,
+				 toplevel);
+  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);
+}
+
+/* end fs_sharetree.c */
+