Added descriptive macros for various commands and responses.

src/pgsql_sock.erl

@@ -19,6 +19,39 @@
 -include("pgsql.hrl").
 -include("pgsql_binary.hrl").
 
+%% Commands defined as per this page:
+%% http://www.postgresql.org/docs/9.2/static/protocol-message-formats.html
+
+%% Commands
+-define(BIND, $B).
+-define(CLOSE, $C).
+-define(DESCRIBE, $D).
+-define(EXECUTE, $E).
+-define(FLUSH, $H).
+-define(PARSE, $P).
+-define(SIMPLEQUERY, $Q).
+-define(AUTHENTICATION_REQUEST, $R).
+-define(SYNC, $S).
+
+%% Parameters
+
+-define(PREPARED_STATEMENT, $S).
+-define(PORTAL, $P).
+
+%% Responses
+
+-define(PARSE_COMPLETE, $1).
+-define(BIND_COMPLETE, $2).
+-define(CLOSE_COMPLETE, $3).
+-define(COMMAND_COMPLETE, $C).
+-define(DATA_ROW, $D).
+-define(CANCELLATION_KEY, $K).
+-define(NO_DATA, $n).
+-define(PORTAL_SUSPENDED, $s).
+-define(PARAMETER_DESCRIPTION, $t).
+-define(ROW_DESCRIPTION, $T).
+-define(READY_FOR_QUERY, $Z).
+
 -record(state, {mod,
                 sock,
                 data = <<>>,
@@ -146,7 +179,7 @@ command({connect, Host, Username, Password, Opts}, State) ->
                   async = Async}};
 
 command({squery, Sql}, State) ->
-    send(State, $Q, [Sql, 0]),
+    send(State, ?SIMPLEQUERY, [Sql, 0]),
     {noreply, State};
 
 %% TODO add fast_equery command that doesn't need parsed statement,
@@ -156,17 +189,17 @@ command({equery, Statement, Parameters}, State) ->
     #statement{name = StatementName, columns = Columns} = Statement,
     Bin1 = pgsql_wire:encode_parameters(Parameters),
     Bin2 = pgsql_wire:encode_formats(Columns),
-    send(State, $B, ["", 0, StatementName, 0, Bin1, Bin2]),
-    send(State, $E, ["", 0, <<0:?int32>>]),
-    send(State, $C, [$S, StatementName, 0]),
-    send(State, $S, []),
+    send(State, ?BIND, ["", 0, StatementName, 0, Bin1, Bin2]),
+    send(State, ?EXECUTE, ["", 0, <<0:?int32>>]),
+    send(State, ?CLOSE, [?PREPARED_STATEMENT, StatementName, 0]),
+    send(State, ?SYNC, []),
     {noreply, State};
 
 command({parse, Name, Sql, Types}, State) ->
     Bin = pgsql_wire:encode_types(Types),
-    send(State, $P, [Name, 0, Sql, 0, Bin]),
-    send(State, $D, [$S, Name, 0]),
-    send(State, $H, []),
+    send(State, ?PARSE, [Name, 0, Sql, 0, Bin]),
+    send(State, ?DESCRIBE, [?PREPARED_STATEMENT, Name, 0]),
+    send(State, ?FLUSH, []),
     {noreply, State};
 
 command({bind, Statement, PortalName, Parameters}, State) ->
@@ -174,13 +207,13 @@ command({bind, Statement, PortalName, Parameters}, State) ->
     Typed_Parameters = lists:zip(Types, Parameters),
     Bin1 = pgsql_wire:encode_parameters(Typed_Parameters),
     Bin2 = pgsql_wire:encode_formats(Columns),
-    send(State, $B, [PortalName, 0, StatementName, 0, Bin1, Bin2]),
-    send(State, $H, []),
+    send(State, ?BIND, [PortalName, 0, StatementName, 0, Bin1, Bin2]),
+    send(State, ?FLUSH, []),
     {noreply, State};
 
 command({execute, _Statement, PortalName, MaxRows}, State) ->
-    send(State, $E, [PortalName, 0, <<MaxRows:?int32>>]),
-    send(State, $H, []),
+    send(State, ?EXECUTE, [PortalName, 0, <<MaxRows:?int32>>]),
+    send(State, ?FLUSH, []),
     {noreply, State};
 
 command({execute_batch, Batch}, State) ->
@@ -194,36 +227,36 @@ command({execute_batch, Batch}, State) ->
                   Typed_Parameters = lists:zip(Types, Parameters),
                   Bin1 = pgsql_wire:encode_parameters(Typed_Parameters),
                   Bin2 = pgsql_wire:encode_formats(Columns),
-                  [pgsql_wire:encode($B, [0, StatementName, 0,
-                                          Bin1, Bin2]),
-                   pgsql_wire:encode($E, [0, <<0:?int32>>])]
+                  [pgsql_wire:encode(?BIND, [0, StatementName, 0,
+                                             Bin1, Bin2]),
+                   pgsql_wire:encode(?EXECUTE, [0, <<0:?int32>>])]
           end,
           Batch),
-    Sync = pgsql_wire:encode($S, []),
+    Sync = pgsql_wire:encode(?SYNC, []),
     do_send(Mod, Sock, [BindExecute, Sync]),
     {noreply, State};
 
 command({describe_statement, Name}, State) ->
-    send(State, $D, [$S, Name, 0]),
-    send(State, $H, []),
+    send(State, ?DESCRIBE, [?PREPARED_STATEMENT, Name, 0]),
+    send(State, ?FLUSH, []),
     {noreply, State};
 
 command({describe_portal, Name}, State) ->
-    send(State, $D, [$P, Name, 0]),
-    send(State, $H, []),
+    send(State, ?DESCRIBE, [?PORTAL, Name, 0]),
+    send(State, ?FLUSH, []),
     {noreply, State};
 
 command({close, Type, Name}, State) ->
     case Type of
-        statement -> Type2 = $S;
-        portal    -> Type2 = $P
+        statement -> Type2 = ?PREPARED_STATEMENT;
+        portal    -> Type2 = ?PORTAL
     end,
-    send(State, $C, [Type2, Name, 0]),
-    send(State, $H, []),
+    send(State, ?CLOSE, [Type2, Name, 0]),
+    send(State, ?FLUSH, []),
     {noreply, State};
 
 command(sync, State) ->
-    send(State, $S, []),
+    send(State, ?SYNC, []),
     {noreply, State#state{sync_required = false}}.
 
 start_ssl(S, Flag, Opts, State) ->
@@ -406,22 +439,22 @@ hex(Bin) ->
 %% -- backend message handling --
 
 %% AuthenticationOk
-auth({$R, <<0:?int32>>}, State) ->
+auth({?AUTHENTICATION_REQUEST, <<0:?int32>>}, State) ->
     {noreply, State#state{handler = initializing}};
 
 %% AuthenticationCleartextPassword
-auth({$R, <<3:?int32>>}, State) ->
+auth({?AUTHENTICATION_REQUEST, <<3:?int32>>}, State) ->
     send(State, $p, [get(password), 0]),
     {noreply, State};
 
 %% AuthenticationMD5Password
-auth({$R, <<5:?int32, Salt:4/binary>>}, State) ->
+auth({?AUTHENTICATION_REQUEST, <<5:?int32, Salt:4/binary>>}, State) ->
     Digest1 = hex(erlang:md5([get(password), get(username)])),
     Str = ["md5", hex(erlang:md5([Digest1, Salt])), 0],
     send(State, $p, Str),
     {noreply, State};
 
-auth({$R, <<M:?int32, _/binary>>}, State) ->
+auth({?AUTHENTICATION_REQUEST, <<M:?int32, _/binary>>}, State) ->
     case M of
         2 -> Method = kerberosV5;
         4 -> Method = crypt;
@@ -446,11 +479,11 @@ auth(Other, State) ->
     on_message(Other, State).
 
 %% BackendKeyData
-initializing({$K, <<Pid:?int32, Key:?int32>>}, State) ->
+initializing({?CANCELLATION_KEY, <<Pid:?int32, Key:?int32>>}, State) ->
     {noreply, State#state{backend = {Pid, Key}}};
 
 %% ReadyForQuery
-initializing({$Z, <<Status:8>>}, State) ->
+initializing({?READY_FOR_QUERY, <<Status:8>>}, State) ->
     #state{parameters = Parameters} = State,
     erase(username),
     erase(password),
@@ -471,17 +504,17 @@ initializing(Other, State) ->
     on_message(Other, State).
 
 %% ParseComplete
-on_message({$1, <<>>}, State) ->
+on_message({?PARSE_COMPLETE, <<>>}, State) ->
     {noreply, State};
 
 %% ParameterDescription
-on_message({$t, <<_Count:?int16, Bin/binary>>}, State) ->
+on_message({?PARAMETER_DESCRIPTION, <<_Count:?int16, Bin/binary>>}, State) ->
     Types = [pgsql_types:oid2type(Oid) || <<Oid:?int32>> <= Bin],
     State2 = notify(State#state{types = Types}, {types, Types}),
     {noreply, State2};
 
 %% RowDescription
-on_message({$T, <<Count:?int16, Bin/binary>>}, State) ->
+on_message({?ROW_DESCRIPTION, <<Count:?int16, Bin/binary>>}, State) ->
     Columns = pgsql_wire:decode_columns(Count, Bin),
     Columns2 =
         case command_tag(State) of
@@ -504,7 +537,7 @@ on_message({$T, <<Count:?int16, Bin/binary>>}, State) ->
     {noreply, State3};
 
 %% NoData
-on_message({$n, <<>>}, State) ->
+on_message({?NO_DATA, <<>>}, State) ->
     State2 = case command_tag(State) of
                  C when C == parse; C == describe_statement ->
                      finish(State, no_data, {ok, make_statement(State)});
@@ -514,7 +547,7 @@ on_message({$n, <<>>}, State) ->
     {noreply, State2};
 
 %% BindComplete
-on_message({$2, <<>>}, State) ->
+on_message({?BIND_COMPLETE, <<>>}, State) ->
     State2 = case command_tag(State) of
                  equery ->
                      %% TODO send Describe as a part of equery, needs text format support
@@ -534,7 +567,7 @@ on_message({$2, <<>>}, State) ->
     {noreply, State2};
 
 %% CloseComplete
-on_message({$3, <<>>}, State) ->
+on_message({?CLOSE_COMPLETE, <<>>}, State) ->
     State2 = case command_tag(State) of
                  equery ->
                      State;
@@ -544,19 +577,19 @@ on_message({$3, <<>>}, State) ->
     {noreply, State2};
 
 %% DataRow
-on_message({$D, <<_Count:?int16, Bin/binary>>}, State) ->
+on_message({?DATA_ROW, <<_Count:?int16, Bin/binary>>}, State) ->
     Data = pgsql_wire:decode_data(get_columns(State), Bin),
     {noreply, add_row(State, Data)};
 
 %% PortalSuspended
-on_message({$s, <<>>}, State) ->
+on_message({?PORTAL_SUSPENDED, <<>>}, State) ->
     State2 = finish(State,
                    suspended,
                    {partial, lists:reverse(State#state.rows)}),
     {noreply, State2};
 
 %% CommandComplete
-on_message({$C, Bin}, State) ->
+on_message({?COMMAND_COMPLETE, Bin}, State) ->
     Complete = pgsql_wire:decode_complete(Bin),
     Command = command_tag(State),
     Notice = {complete, Complete},