From 38bd48dff3e7a7c1e5c19b64a3105d74791c64ac Mon Sep 17 00:00:00 2001
From: Dave Smith <dsmith@thehive.com>
Date: Tue, 9 Dec 2008 13:19:12 -0700
Subject: [PATCH] Adding support for calls to begin/commit txns and get/put

---
 src/bdberl_port.erl | 86 ++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 81 insertions(+), 5 deletions(-)

diff --git a/src/bdberl_port.erl b/src/bdberl_port.erl
index 1626509..5a965f1 100644
--- a/src/bdberl_port.erl
+++ b/src/bdberl_port.erl
@@ -8,17 +8,34 @@
 
 -export([new/0,
          open_database/3,
-         close_database/2]).
+         close_database/2,
+         txn_begin/1, txn_commit/1,
+         put/4,
+         get/3]).
 
--define(CMD_OPEN_DB, 0).
--define(CMD_CLOSE_DB, 1).
+-define(CMD_NONE,       0).
+-define(CMD_OPEN_DB,    1).
+-define(CMD_CLOSE_DB,   2).
+-define(CMD_TXN_BEGIN,  3).
+-define(CMD_TXN_COMMIT, 4).
+-define(CMD_TXN_ABORT,  5).
+-define(CMD_GET,        6).
+-define(CMD_PUT,        7).
+-define(CMD_PUT_ATOMIC, 8).
 
 -define(DB_TYPE_BTREE, 1).
--define(DB_TYPE_HASH, 2).
+-define(DB_TYPE_HASH,  2).
 
--define(STATUS_OK, 0).
+-define(STATUS_OK,    0).
 -define(STATUS_ERROR, 1).
 
+-define(ERROR_NONE,          0).
+-define(ERROR_MAX_DBS,       -29000).           % System can not open any more databases
+-define(ERROR_ASYNC_PENDING, -29001).           % Async operation already pending on this port
+-define(ERROR_INVALID_DBREF, -29002).           % DbRef not currently opened by this port
+-define(ERROR_TXN_OPEN,      -29003).           % Transaction already active on this port
+-define(ERROR_NO_TXN,        -29004).           % No transaction open on this port
+
 new() ->
     ok = erl_ddll:load_driver(code:priv_dir(bdberl), bdberl_drv),
     Port = open_port({spawn, bdberl_drv}, [binary]),
@@ -48,3 +65,62 @@ close_database(Port, DbRef) ->
             ok
     end.
 
+txn_begin(Port) ->
+    <<Result:32/native>> = erlang:port_control(Port, ?CMD_TXN_BEGIN, <<>>),
+    case Result of
+        ?ERROR_NONE -> ok;
+        ?ERROR_ASYNC_PENDING -> {error, async_pending};
+        ?ERROR_TXN_OPEN -> {error, txn_open}
+    end.
+
+txn_commit(Port) ->
+    <<Result:32/native>> = erlang:port_control(Port, ?CMD_TXN_COMMIT, <<>>),
+    case Result of
+        ?ERROR_NONE -> 
+            receive
+                ok -> ok;
+                {error, Reason} -> {error, Reason}
+            end;
+        ?ERROR_ASYNC_PENDING -> {error, async_pending};
+        ?ERROR_NO_TXN -> {error, no_txn}
+    end.
+            
+            
+put(Port, DbRef, Key, Value) ->
+    {KeyLen, KeyBin} = to_binary(Key),
+    {ValLen, ValBin} = to_binary(Value),
+    Cmd = <<DbRef:32/native, KeyLen:32/native, KeyBin/bytes, ValLen:32/native, ValBin/bytes>>,
+    <<Result:32/native>> = erlang:port_control(Port, ?CMD_PUT, Cmd),
+    case Result of
+        ?ERROR_NONE -> 
+            receive
+                ok -> ok;
+                {error, Reason} -> {error, Reason}
+            end;
+        ?ERROR_ASYNC_PENDING -> {error, async_pending};
+        ?ERROR_INVALID_DBREF -> {error, invalid_dbref}
+    end.
+
+
+get(Port, DbRef, Key) ->
+    {KeyLen, KeyBin} = to_binary(Key),
+    Cmd = <<DbRef:32/native, KeyLen:32/native, KeyBin/bytes>>,
+    <<Result:32/native>> = erlang:port_control(Port, ?CMD_GET, Cmd),
+    case Result of
+        ?ERROR_NONE ->
+            receive
+                {ok, Bin} -> {ok, binary_to_term(Bin)};
+                {error, Reason} -> {error, Reason}
+            end;
+        ?ERROR_ASYNC_PENDING -> {error, async_pending};
+        ?ERROR_INVALID_DBREF -> {error, invalid_dbref}
+    end.
+    
+            
+
+
+
+to_binary(Term) ->
+    Bin = term_to_binary(Term),
+    {size(Bin), Bin}.
+