add proximity considerations to datacache

1 files changed, 111 insertions, 6 deletions

diff --git a/src/datacache/plugin_datacache_heap.c b/src/datacache/plugin_datacache_heap.c
index 49e60bca1..c32edf8e2 100644
--- a/src/datacache/plugin_datacache_heap.c
+++ b/src/datacache/plugin_datacache_heap.c
@@ -53,6 +53,11 @@ struct Plugin
    */
   struct GNUNET_CONTAINER_Heap *heap;
 
+  /**
+   * Heap from the plugin for "closest" values.
+   */
+  struct GNUNET_CONTAINER_Heap *cheap;
+
 };
 
 
@@ -92,6 +97,11 @@ struct Value
   unsigned int path_info_len;
 
   /**
+   * Am I the closest peer? Determines which heap we are in!
+   */
+  int am_closest;
+
+  /**
    * Type of the block.
    */
   enum GNUNET_BLOCK_Type type;
@@ -118,6 +128,11 @@ struct PutContext
   const char *data;
 
   /**
+   * Heap from the plugin for "closest" values.
+   */
+  struct GNUNET_CONTAINER_Heap *cheap;
+
+  /**
    * Heap from the plugin.
    */
   struct GNUNET_CONTAINER_Heap *heap;
@@ -168,7 +183,9 @@ put_cb (void *cls,
 
   if ( (val->size == put_ctx->size) &&
        (val->type == put_ctx->type) &&
-       (0 == memcmp (&val[1], put_ctx->data, put_ctx->size)) )
+       (0 == memcmp (&val[1],
+                     put_ctx->data,
+                     put_ctx->size)) )
   {
     put_ctx->found = GNUNET_YES;
     val->discard_time = GNUNET_TIME_absolute_max (val->discard_time,
@@ -199,6 +216,7 @@ put_cb (void *cls,
  *
  * @param cls closure (our `struct Plugin`)
  * @param key key to store data under
+ * @param am_closest are we the closest peer?
  * @param size number of bytes in @a data
  * @param data data to store
  * @param type type of the value
@@ -210,6 +228,7 @@ put_cb (void *cls,
 static ssize_t
 heap_plugin_put (void *cls,
                  const struct GNUNET_HashCode *key,
+                 int am_closest,
                  size_t size,
                  const char *data,
                  enum GNUNET_BLOCK_Type type,
@@ -223,6 +242,7 @@ heap_plugin_put (void *cls,
 
   put_ctx.found = GNUNET_NO;
   put_ctx.heap = plugin->heap;
+  put_ctx.cheap = plugin->cheap;
   put_ctx.data = data;
   put_ctx.size = size;
   put_ctx.path_info = path_info;
@@ -241,17 +261,20 @@ heap_plugin_put (void *cls,
   val->type = type;
   val->discard_time = discard_time;
   val->size = size;
+  val->am_closest = am_closest;
   GNUNET_array_grow (val->path_info,
                      val->path_info_len,
                      path_info_len);
   GNUNET_memcpy (val->path_info,
-          path_info,
-          path_info_len * sizeof (struct GNUNET_PeerIdentity));
+                 path_info,
+                 path_info_len * sizeof (struct GNUNET_PeerIdentity));
   (void) GNUNET_CONTAINER_multihashmap_put (plugin->map,
                                             &val->key,
                                             val,
                                             GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE);
-  val->hn = GNUNET_CONTAINER_heap_insert (plugin->heap,
+  val->hn = GNUNET_CONTAINER_heap_insert (am_closest
+                                          ? plugin->cheap
+                                          : plugin->heap,
                                           val,
                                           val->discard_time.abs_value_us);
   return size + OVERHEAD;
@@ -371,6 +394,8 @@ heap_plugin_del (void *cls)
 
   val = GNUNET_CONTAINER_heap_remove_root (plugin->heap);
   if (NULL == val)
+    val = GNUNET_CONTAINER_heap_remove_root (plugin->cheap);
+  if (NULL == val)
     return GNUNET_SYSERR;
   GNUNET_assert (GNUNET_YES ==
                  GNUNET_CONTAINER_multihashmap_remove (plugin->map,
@@ -413,6 +438,53 @@ heap_plugin_get_random (void *cls,
 
 
 /**
+ * Closure for #find_closest().
+ */
+struct GetClosestContext
+{
+  struct Value **values;
+
+  unsigned int num_results;
+
+  const struct GNUNET_HashCode *key;
+};
+
+
+static int
+find_closest (void *cls,
+              const struct GNUNET_HashCode *key,
+              void *value)
+{
+  struct GetClosestContext *gcc = cls;
+  struct Value *val = value;
+  unsigned int j;
+
+  if (1 != GNUNET_CRYPTO_hash_cmp (key,
+                                   gcc->key))
+    return GNUNET_OK; /* useless */
+  j = gcc->num_results;
+  for (unsigned int i=0;i<gcc->num_results;i++)
+  {
+    if (NULL == gcc->values[i])
+    {
+      j = i;
+      break;
+    }
+    if (1 == GNUNET_CRYPTO_hash_cmp (&gcc->values[i]->key,
+                                     key))
+    {
+      j = i;
+      break;
+    }
+  }
+  if (j == gcc->num_results)
+    return GNUNET_OK;
+  gcc->values[j] = val;
+  return GNUNET_OK;
+}
+
+
+/**
  * Iterate over the results that are "close" to a particular key in
  * the datacache.  "close" is defined as numerically larger than @a
  * key (when interpreted as a circular address space), with small
@@ -432,8 +504,30 @@ heap_plugin_get_closest (void *cls,
                          GNUNET_DATACACHE_Iterator iter,
                          void *iter_cls)
 {
-  GNUNET_break (0); // not implemented!
-  return 0;
+  struct Plugin *plugin = cls;
+  struct Value *values[num_results];
+  struct GetClosestContext gcc = {
+    .values = values,
+    .num_results = num_results,
+    .key = key
+  };
+  GNUNET_CONTAINER_multihashmap_iterate (plugin->map,
+                                         &find_closest,
+                                         &gcc);
+  for (unsigned int i=0;i<num_results;i++)
+  {
+    if (NULL == values[i])
+      return i;
+    iter (iter_cls,
+          &values[i]->key,
+          values[i]->size,
+          (void *) &values[i][1],
+          values[i]->type,
+          values[i]->discard_time,
+          values[i]->path_info_len,
+          values[i]->path_info);
+  }
+  return num_results;
 }
 
 
@@ -454,6 +548,7 @@ libgnunet_plugin_datacache_heap_init (void *cls)
   plugin->map = GNUNET_CONTAINER_multihashmap_create (1024,  /* FIXME: base on quota! */
                                                       GNUNET_YES);
   plugin->heap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
+  plugin->cheap = GNUNET_CONTAINER_heap_create (GNUNET_CONTAINER_HEAP_ORDER_MIN);
   plugin->env = env;
   api = GNUNET_new (struct GNUNET_DATACACHE_PluginFunctions);
   api->cls = plugin;
@@ -490,7 +585,17 @@ libgnunet_plugin_datacache_heap_done (void *cls)
     GNUNET_free_non_null (val->path_info);
     GNUNET_free (val);
   }
+  while (NULL != (val = GNUNET_CONTAINER_heap_remove_root (plugin->cheap)))
+  {
+    GNUNET_assert (GNUNET_YES ==
+                   GNUNET_CONTAINER_multihashmap_remove (plugin->map,
+                                                         &val->key,
+                                                         val));
+    GNUNET_free_non_null (val->path_info);
+    GNUNET_free (val);
+  }
   GNUNET_CONTAINER_heap_destroy (plugin->heap);
+  GNUNET_CONTAINER_heap_destroy (plugin->cheap);
   GNUNET_CONTAINER_multihashmap_destroy (plugin->map);
   GNUNET_free (plugin);
   GNUNET_free (api);