From 876136763a49adc76eb4e9fe4a7a9dc78fb9a171 Mon Sep 17 00:00:00 2001
From: Brian Cully <bjc@kublai.com>
Date: Sat, 1 Mar 2008 17:01:46 -0500
Subject: Use erl_interface instead of custom protocol.

---
 src/mysqlerl.c              | 61 +++++++++++++++++++++++++--------------------
 src/mysqlerl_connection.erl |  9 +++++--
 2 files changed, 41 insertions(+), 29 deletions(-)

diff --git a/src/mysqlerl.c b/src/mysqlerl.c
index b4e6441..b5ad31c 100644
--- a/src/mysqlerl.c
+++ b/src/mysqlerl.c
@@ -19,16 +19,13 @@
 const char *LOGPATH = "/tmp/mysqlerl.log";
 static FILE *logfile = NULL;
 
+const char *QUERY_MSG = "sql_query";
+
 typedef u_int32_t msglen_t;
-typedef enum {
-  QUERY_MSG = 0, COMMIT_MSG = 1, ROLLBACK_MSG = 2, EXTENDED_MSG = 255
-} msgtype_t;
 
 struct msg {
-  msgtype_t type;
-  char *msg;
-  size_t msglen;
-  char *buf;
+  ETERM *cmd;
+  unsigned char *buf;
 };
 typedef struct msg msg_t;
 
@@ -62,7 +59,7 @@ logmsg(const char *format, ...)
 }
 
 int
-restartable_read(char *buf, size_t buflen)
+restartable_read(unsigned char *buf, size_t buflen)
 {
   ssize_t rc, readb;
 
@@ -88,7 +85,7 @@ restartable_read(char *buf, size_t buflen)
 }
 
 int
-restartable_write(const char *buf, size_t buflen)
+restartable_write(const unsigned char *buf, size_t buflen)
 {
   ssize_t rc, wroteb;
 
@@ -124,16 +121,16 @@ read_msg()
   }
 
   logmsg("DEBUG: reading message length.");
-  if (restartable_read((char *)&len, sizeof(len)) == -1) {
+  if (restartable_read((unsigned char *)&len, sizeof(len)) == -1) {
     logmsg("ERROR: couldn't read %d byte message prefix: %s.",
            sizeof(len), strerror(errno));
 
     free(msg);
     exit(2);
   }
-  len = ntohl(len);
 
-  msg->buf = malloc(len + 1);
+  len = ntohl(len);
+  msg->buf = malloc(len);
   if (msg->buf == NULL) {
     logmsg("ERROR: Couldn't malloc %d bytes: %s.", len,
            strerror(errno));
@@ -141,7 +138,6 @@ read_msg()
     free(msg);
     exit(2);
   }
-  msg->buf[len] = '\0';
 
   logmsg("DEBUG: reading message body (len: %d).", len);
   if (restartable_read(msg->buf, len) == -1) {
@@ -153,9 +149,7 @@ read_msg()
     exit(2);
   }
 
-  msg->type   = msg->buf[0];
-  msg->msg    = msg->buf + 1;
-  msg->msglen = len - 1;
+  msg->cmd = erl_decode(msg->buf);
 
   return msg;
 }
@@ -166,11 +160,11 @@ write_cmd(const char *cmd, msglen_t len)
   msglen_t nlen;
 
   nlen = htonl(len + 3);
-  if (restartable_write((char *)&nlen, sizeof(nlen)) == -1)
+  if (restartable_write((unsigned char *)&nlen, sizeof(nlen)) == -1)
     return -1;
-  if (restartable_write(" - ", 3) == -1)
+  if (restartable_write((unsigned char *)" - ", 3) == -1)
     return -1;
-  if (restartable_write(cmd, len) == -1)
+  if (restartable_write((unsigned char *)cmd, len) == -1)
     return -1;
 
   return 0;
@@ -179,16 +173,26 @@ write_cmd(const char *cmd, msglen_t len)
 void
 dispatch_db_cmd(MYSQL *dbh, msg_t *msg)
 {
-  switch (msg->type) {
-  case QUERY_MSG:
-    logmsg("DEBUG: got query msg: %s.", msg->msg);
-    write_cmd(msg->msg, msg->msglen);
-    break;
-
-  default:
-    logmsg("WARNING: message type %d unknown.", msg->type);
+  ETERM *tag;
+
+  tag = erl_element(1, msg->cmd);
+  if (strncmp((char *)ERL_ATOM_PTR(tag), QUERY_MSG, sizeof(QUERY_MSG)) == 0) {
+    ETERM *query;
+    char *q;
+    query = erl_element(2, msg->cmd);
+    q = erl_iolist_to_string(query);
+    erl_free_term(query);
+
+    logmsg("DEBUG: got query msg: %s.", q);
+    write_cmd(q, strlen(q));
+    erl_free(q);
+  } else {
+    logmsg("WARNING: message type %s unknown.", (char *)ERL_ATOM_PTR(tag));
+    erl_free_term(tag);
     exit(3);
   }
+
+  erl_free_term(tag);
 }
 
 void
@@ -217,6 +221,8 @@ main(int argc, char *argv[])
   user    = argv[4];
   passwd  = argv[5];
 
+  erl_init(NULL, 0);
+
   mysql_init(&dbh);
   if (mysql_real_connect(&dbh, host, user, passwd,
                          db_name, atoi(port), NULL, 0) == NULL) {
@@ -229,6 +235,7 @@ main(int argc, char *argv[])
     dispatch_db_cmd(&dbh, msg);
 
     /* XXX: Move this to function */
+    erl_free_compound(msg->cmd);
     free(msg->buf);
     free(msg);
   }
diff --git a/src/mysqlerl_connection.erl b/src/mysqlerl_connection.erl
index 52a6300..fb0479c 100644
--- a/src/mysqlerl_connection.erl
+++ b/src/mysqlerl_connection.erl
@@ -9,6 +9,8 @@
          handle_call/3, handle_cast/2, handle_info/2]).
 
 -define(QUERY_MSG, 0).
+-define(COMMIT_MSG, 1).
+-define(ROLLBACK_MSG, 2).
 -define(EXTENDED_MSG, 255).
 
 -record(state, {ref}).
@@ -30,7 +32,7 @@ init([Host, Port, Database, User, Password, Options]) ->
     Cmd = lists:flatten(io_lib:format("~s ~s ~w ~s ~s ~s ~s",
                                       [helper(), Host, Port, Database,
                                        User, Password, Options])),
-    Ref = open_port({spawn, Cmd}, [{packet, 4}]),
+    Ref = open_port({spawn, Cmd}, [{packet, 4}, binary]),
     {ok, #state{ref = Ref}}.
 
 terminate(#port_closed{reason = Reason}, #state{ref = Ref}) ->
@@ -69,7 +71,10 @@ helper() ->
 
 handle_query(Ref, Query) ->
     io:format("DEBUG: got query: ~p~n", [Query]),
-    port_command(Ref, [?QUERY_MSG | Query]),
+    make_request(Ref, {sql_query, Query}).
+
+make_request(Ref, Req) ->
+    port_command(Ref, term_to_binary(Req)),
     receive
         {Ref, {data, Res}} -> {ok, Res};
         Other ->
-- 
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