Update DESIGN.txt and code accordingly

src/chunk_server.h

@@ -3,6 +3,7 @@
 
 #include <limits.h>
 
+#include "metadata_server.h"
 #include "tcp.h"
 
 #define TAG_METADATA_SERVER 1
@@ -27,25 +28,42 @@ typedef struct {
 
 typedef struct {
     SHA256 hash;
-    Time   marked_time;
-} PendingRemoval;
+    Time   time;
+} TimedHash;
 
 typedef struct {
     int count;
     int capacity;
-    PendingRemoval *items;
-} RemovalList;
+    TimedHash *items;
+} TimedHashList;
 
 typedef struct {
-    bool       trace;
-    Address    local_addr;
-    Address    remote_addr;
-    Time       disconnect_time;
-    TCP        tcp;
+
+    bool trace;
+
+    Address local_addr;
+
+    Address remote_addr;
+
+    Time disconnect_time;
+
+    TCP tcp;
+
     ChunkStore store;
+
     bool downloading;
+
     PendingDownloadList pending_download_list;
-    RemovalList removal_list;
+
+    // List of chunks added since the last update
+    HashList cs_add_list;
+
+    // List of chunks marked for removal after a timeout
+    TimedHashList cs_rem_list;
+
+    // List of chunks that were lost due to errors or forceful removals of chunk files
+    HashList cs_lst_list;
+
 } ChunkServer;
 
 int chunk_server_init(ChunkServer *state, int argc, char **argv, void **contexts, struct pollfd *polled, int *timeout);