1 files changed, 100 insertions, 16 deletions

diff --git a/lib/manager.ex b/lib/manager.ex
index 87f95c5..b547312 100644
--- a/lib/manager.ex
+++ b/lib/manager.ex
@@ -1,6 +1,6 @@
 defmodule Shard.Manager do
   @moduledoc"""
-    Maintains two important tables :
+    Maintains several important tables :
 
     - :peer_db
       
@@ -10,14 +10,20 @@ defmodule Shard.Manager do
     - :shard_db
     
       List of
-        { id, manifest, shard_pid }
+        { id, manifest, pid | nil }
 
-    And also some others :
+    - :shard_procs
 
-    - :peer_shard_db
+      List of
+        { {id, path}, pid }
+
+    - :shard_peer_db
 
       Mult-list of
-        { peer_id, shard_id }
+        { shard_id, peer_id }
+
+
+    And an internal table :
 
     - :outbox
       
@@ -37,10 +43,11 @@ defmodule Shard.Manager do
   def init(my_port) do
     :ets.new(:peer_db, [:set, :protected, :named_table])
     :ets.new(:shard_db, [:set, :protected, :named_table])
-    peer_shard_db = :ets.new(:peer_shard_db, [:bag, :private])
+    :ets.new(:shard_procs, [:set, :protected, :named_table])
+    :ets.new(:shard_peer_db, [:bag, :protected, :named_table])
     outbox = :ets.new(:outbox, [:bag, :private])
 
-    {:ok, %{my_port: my_port, peer_shard_db: peer_shard_db, outbox: outbox} }
+    {:ok, %{my_port: my_port, outbox: outbox} }
   end
 
   def handle_call({:find, shard_id}, _from, state) do
@@ -51,16 +58,24 @@ defmodule Shard.Manager do
     {:reply, reply, state}
   end
 
-  def handle_cast({:register, shard_id, manifest, pid}, state) do
+  def handle_call({:register, shard_id, manifest, pid}, _from, state) do
     will_live = case :ets.lookup(:shard_db, shard_id) do
       [{ ^shard_id, _, pid }] -> not Process.alive?(pid)
       _ -> true
     end
-    if will_live do
+    reply = if will_live do
+      Process.monitor(pid)
       :ets.insert(:shard_db, {shard_id, manifest, pid})
+      :ok
     else
-      GenServer.cast(pid, {:redundant, shard_id})
+      :redundant
     end
+    {:reply, reply, state}
+  end
+
+  def handle_cast({:dispatch_to, shard_id, path, pid}, state) do
+    :ets.insert(:shard_procs, { {shard_id, path}, pid })
+    Process.monitor(pid)
     {:noreply, state}
   end
 
@@ -68,7 +83,7 @@ defmodule Shard.Manager do
     for shard_id <- shards do
       case :ets.lookup(:shard_db, shard_id) do
         [{ ^shard_id, _, pid }] ->
-          :ets.insert(state.peer_shard_db, {peer_id, shard_id})
+          :ets.insert(:shard_peer_db, {shard_id, peer_id})
           GenServer.cast(pid, {:interested, peer_id})
         [] -> nil
       end
@@ -76,14 +91,29 @@ defmodule Shard.Manager do
     {:noreply, state}
   end
 
+  def handle_cast({:not_interested, peer_id, shard_id}, state) do
+    :ets.match_delete(:shard_peer_db, {shard_id, peer_id})
+    {:noreply, state}
+  end
 
+  def handle_cast({:shard_peer_db_insert, shard_id, peer_id}, state) do
+    :ets.insert(:shard_peer_db, {shard_id, peer_id})
+    {:noreply, state}
+  end
 
   def handle_cast({:peer_up, pk, pid, ip, port}, state) do
     :ets.insert(:peer_db, {pk, pid, ip, port})
+
+    # Send interested message for all our shards
+    id_list = (for {id, _, _} <- :ets.tab2list(:shard_db), do: id)
+    GenServer.cast(pid, {:send_msg, {:interested, id_list}})
+
+    # Send queued messages
     for {_, msg, _} <- :ets.lookup(state.outbox, pk) do
       GenServer.cast(pid, {:send_msg, msg})
     end
     :ets.delete(state.outbox, pk)
+
     {:noreply, state}
   end
 
@@ -123,6 +153,11 @@ defmodule Shard.Manager do
     {:noreply, state}
   end
 
+  def handle_info({:DOWN, _, :process, pid, _}, state) do
+    :ets.match_delete(:shard_procs, {:_, pid})
+    {:noreply, state}
+  end
+
   defp add_peer(ip, port, state) do
     spawn fn ->
       case :gen_tcp.connect(ip, port, [:binary, packet: 2, active: false]) do
@@ -135,10 +170,22 @@ defmodule Shard.Manager do
     end
   end
 
+
+  # ================
+  # PUBLIC INTERFACE
+  # ================
+  
+
+  @doc"""
+  Connect to a peer specified by ip address and port
+  """
   def add_peer(ip, port) do
     GenServer.cast(__MODULE__, {:add_peer, ip, port})
   end
 
+  @doc"""
+  Send message to a peer specified by peer id
+  """
   def send(peer_id, msg) do
     case :ets.lookup(:peer_db, peer_id) do
       [{ ^peer_id, pid, _, _}] when pid != nil->
@@ -148,12 +195,49 @@ defmodule Shard.Manager do
     end
   end
 
-  def dispatch(peer_id, shard_id, msg) do
+  @doc"""
+  Dispatch incoming message to correct shard process
+  """
+  def dispatch(peer_id, {shard_id, path, msg}) do
     case :ets.lookup(:shard_db, shard_id) do
-        [{ ^shard_id, _, pid }] when pid != nil ->
-          GenServer.cast(pid, {:msg, peer_id, msg})
-        [_] -> nil # TODO restart shard
-        [] -> nil  # TODO send not interested
+      [] ->
+        __MODULE__.send(peer_id, {:not_interested, shard_id})
+      [_] ->
+        case :ets.match(:shard_peer_db, {shard_id, peer_id}) do
+          [] ->
+            GenServer.cast(__MODULE__, {:shard_peer_db_insert, shard_id, peer_id})
+          _ -> nil
+        end
+        case :ets.lookup(:shard_procs, {shard_id, path}) do
+          [{ {^shard_id, ^path}, pid }] ->
+            GenServer.cast(pid, {:msg, peer_id, shard_id, path, msg})
+          [] ->
+            Logger.info("Warning: dropping message for #{inspect shard_id}/#{inspect path}, no handler running.\n\t#{inspect msg}")
+        end
     end
   end
+
+  def dispatch(peer_id, {:interested, shards}) do
+    GenServer.cast(__MODULE__, {:interested, peer_id, shards})
+  end
+
+  def dispatch(peer_id, {:not_interested, shard}) do
+    GenServer.cast(__MODULE__, {:not_interested, peer_id, shard})
+  end
+
+  @doc"""
+  Register a process as the main process for a shard.
+
+  Returns either :ok or :redundant, in which case the process must exit.
+  """
+  def register(shard_id, manifest, pid) do
+    GenServer.call(__MODULE__, {:register, shard_id, manifest, pid})
+  end
+
+  @doc"""
+  Register a process as the handler for shard packets for a given path.
+  """
+  def dispatch_to(shard_id, path, pid) do
+    GenServer.cast(__MODULE__, {:dispatch_to, shard_id, path, pid})
+  end
 end