Initial commit

9 files changed, 566 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b36fc75
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+*~
+*.o
+*.beam
+mysqlerl
+ebin/*
+priv/*
\ No newline at end of file
diff --git a/README b/README
new file mode 100644
index 0000000..d677b52
--- /dev/null
+++ b/README
@@ -0,0 +1,6 @@
+Currently, all the MySQL drivers I've found use direct socket access
+on knowledge of wire protocol in order to connect and manipulate MySQL
+DBs.
+
+This is an attempt to fix that. This library will run as a port driver
+and use libmysqlclient instead.
\ No newline at end of file
diff --git a/src/Makefile b/src/Makefile
new file mode 100644
index 0000000..3978bf0
--- /dev/null
+++ b/src/Makefile
@@ -0,0 +1,34 @@
+CFLAGS =	-I/usr/local/mysql/include -O2 -g
+LDFLAGS =	-L/usr/local/mysql/lib
+EFLAGS =	-W +debug_info
+
+PRIVDIR =	../priv
+BEAMDIR =	../ebin
+
+BINS =		$(PRIVDIR)/mysqlerl $(BEAMDIR)/mysqlerl.app
+MYSQLERLOBJS =	mysqlerl.o
+BEAMS =		mysqlerl.beam mysqlerl_app.beam mysqlerl_connection.beam \
+		mysqlerl_connection_sup.beam
+LIBS =		-lmysqlclient
+
+all:	$(PRIVDIR) $(BEAMDIR) $(BINS)
+
+clean:
+	rm -rf *.o *.beam
+	rm -rf $(BINS) $(MYSQLERLOBJS) $(BEAMS) $(BEAMDIR)/mysqlerl.app
+
+%.beam: %.erl
+	erlc $(EFLAGS) $<
+
+$(PRIVDIR)/mysqlerl: $(PRIVDIR) $(MYSQLERLOBJS)
+	$(CC) -o $@ $(LDFLAGS) $(MYSQLERLOBJS) $(LIBS)
+
+$(BEAMDIR)/mysqlerl.app: $(BEAMDIR) $(BEAMS)
+	cp $(BEAMS) $(BEAMDIR)
+	cp mysqlerl.app $(BEAMDIR)
+
+$(PRIVDIR):
+	mkdir -p $(PRIVDIR)
+
+$(BEAMDIR):
+	mkdir -p $(BEAMDIR)
\ No newline at end of file
diff --git a/src/mysqlerl.app b/src/mysqlerl.app
new file mode 100644
index 0000000..3cc97b6
--- /dev/null
+++ b/src/mysqlerl.app
@@ -0,0 +1,11 @@
+%% -*- Erlang -*-
+
+{application, mysqlerl,
+ [{description, "mysqlerl"},
+  {vsn, "0"},
+  {modules, [mysqlerl, mysqlerl_app, mysqlerl_connection_sup,
+             mysqlerl_connection]},
+  {registered, [mysqlerl, mysqlerl_app, mysqlerl_connection_sup]},
+  {applications, [kernel, stdlib]},
+  {env, []},
+  {mod, {mysqlerl_app, []}}]}.
diff --git a/src/mysqlerl.c b/src/mysqlerl.c
new file mode 100644
index 0000000..d65dba1
--- /dev/null
+++ b/src/mysqlerl.c
@@ -0,0 +1,190 @@
+#include <mysql.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+const char *LOGPATH = "/tmp/mysqlerl.log";
+const size_t BUFSIZE = 2048;
+static FILE *logfile = NULL;
+
+typedef u_int32_t msglen_t;
+
+void
+openlog()
+{
+  logfile = fopen(LOGPATH, "a");
+}
+
+void
+closelog()
+{
+  fclose(logfile);
+}
+
+void
+logmsg(const char *format, ...)
+{
+  FILE *out = logfile;
+  va_list args;
+
+  if (logfile == NULL)
+    logfile = stderr;
+
+  va_start(args, format);
+  (void)vfprintf(logfile, format, args);
+  (void)fprintf(logfile, "\n");
+  va_end(args);
+
+  fflush(logfile);
+}
+
+int
+restartable_read(char *buf, size_t buflen)
+{
+  ssize_t rc, readb;
+
+  rc = 0;
+  READLOOP:
+  while (rc < buflen) {
+    readb = read(STDIN_FILENO, buf + rc, buflen - rc);
+    if (readb == -1) {
+      if (errno == EAGAIN || errno == EINTR)
+        goto READLOOP;
+
+      return -1;
+    } else if (readb == 0) {
+      logmsg("ERROR: EOF trying to read additional %d bytes from "
+             "standard input", buflen - rc);
+      return -1;
+    }
+
+    rc += readb;
+  }
+
+  return rc;
+}
+
+int
+restartable_write(const char *buf, size_t buflen)
+{
+  ssize_t rc, wroteb;
+
+  rc = 0;
+  WRITELOOP:
+  while (rc < buflen) {
+    wroteb = write(STDOUT_FILENO, buf + rc, buflen - rc);
+    if (wroteb == -1) {
+      if (errno == EAGAIN || errno == EINTR)
+        goto WRITELOOP;
+
+      return -1;
+    }
+
+    rc += wroteb;
+  }
+
+  return rc;
+}
+
+char *
+read_cmd()
+{
+  char *buf;
+  msglen_t len;
+
+  logmsg("DEBUG: reading message length.");
+  if (restartable_read((char *)&len, sizeof(len)) == -1) {
+    logmsg("ERROR: couldn't read %d byte message prefix: %s.",
+           sizeof(len), strerror(errno));
+    exit(2);
+  }
+  len = ntohl(len);
+
+  buf = malloc(len);
+  if (buf == NULL) {
+    logmsg("ERROR: Couldn't malloc %d bytes: %s.", len,
+           strerror(errno));
+    exit(2);
+  }
+  memset(buf, 0, BUFSIZE);
+
+  logmsg("DEBUG: reading message body (len: %d).", len);
+  if (restartable_read(buf, len) == -1) {
+    logmsg("ERROR: couldn't read %d byte message: %s.",
+           len, strerror(errno));
+    exit(2);
+  }
+
+  return buf;
+}
+
+int
+write_cmd(const char *cmd, msglen_t len)
+{
+  msglen_t nlen;
+
+  nlen = htonl(len + 3);
+  restartable_write((char *)&nlen, sizeof(nlen));
+  restartable_write(" - ", 3);
+  restartable_write(cmd, len);
+}
+
+void
+dispatch_db_cmd(MYSQL *dbh, const char *cmd)
+{
+  msglen_t len, nlen;
+
+  logmsg("DEBUG: dispatch_cmd(\"%s\")", cmd);
+  write_cmd(cmd, strlen(cmd));
+}
+
+void
+usage()
+{
+  fprintf(stderr, "Usage: mysqlerl host port db_name user passwd\n");
+  exit(1);
+}
+
+int
+main(int argc, char *argv[])
+{
+  MYSQL dbh;
+  char *host, *port, *db_name, *user, *passwd, *cmd;
+
+  openlog();
+  logmsg("INFO: starting up.");
+
+  if (argc < 6)
+    usage();
+
+  host    = argv[1];
+  port    = argv[2];
+  db_name = argv[3];
+  user    = argv[4];
+  passwd  = argv[5];
+
+  mysql_init(&dbh);
+  if (mysql_real_connect(&dbh, host, user, passwd,
+                         db_name, atoi(port), NULL, 0) == NULL) {
+    logmsg("ERROR: Failed to connect to database %s: %s (%s:%s).",
+           db_name, mysql_error(&dbh), user, passwd);
+    exit(2);
+  }
+
+  while ((cmd = read_cmd()) != NULL) {
+    dispatch_db_cmd(&dbh, cmd);
+    free(cmd);
+  }
+
+  mysql_close(&dbh);
+
+  logmsg("INFO: shutting down.");
+  closelog();
+
+  return 0;
+}
diff --git a/src/mysqlerl.erl b/src/mysqlerl.erl
new file mode 100644
index 0000000..68185a2
--- /dev/null
+++ b/src/mysqlerl.erl
@@ -0,0 +1,196 @@
+%% Modeled from ODBC
+%% http://www.erlang.org/doc/apps/odbc/
+
+-module(mysqlerl).
+-author('bjc@kublai.com').
+
+-export([test_start/0, test_msg/0]).
+
+-export([start/0, start/1, stop/0, commit/2, commit/3,
+         connect/6, disconnect/1, describe_table/2,
+         describe_table/3, first/1, first/2,
+         last/1, last/2, next/1, next/2, prev/1,
+         prev/2, select_count/2, select_count/3,
+         select/3, select/4, param_query/3, param_query/4,
+         sql_query/2, sql_query/3]).
+
+-define(CONFIG, "/Users/bjc/tmp/test-server.cfg").
+-define(NOTIMPLEMENTED, {error, {not_implemented,
+                                 "This function has only been stubbed "
+                                 "out for reference."}}).
+
+test_start() ->
+    {ok, [{Host, Port, DB, User, Pass, Options}]} = file:consult(?CONFIG),
+    mysqlerl:connect(Host, Port, DB, User, Pass, Options).
+
+test_msg() ->
+    mysqlerl_connection:testmsg(mysqlerl_connection_sup:random_child()).
+
+start() ->
+    start(temporary).
+
+%% Arguments:
+%%     Type = permanent | transient | temporary
+%%
+%% Returns:
+%%     ok | {error, Reason}
+start(Type) ->
+    application:start(sasl),
+    application:start(mysqlerl, Type).
+
+stop() ->
+    application:stop(mysqlerl).
+
+commit(Ref, CommitMode) ->
+    commit(Ref, CommitMode, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Timeout = time_out()
+%%     CommitMode = commit | rollback
+%%     Reason = not_an_explicit_commit_connection |
+%%              process_not_owner_of_odbc_connection |
+%%              common_reason()
+%%     ok | {error, Reason}
+commit(Ref, commit, Timeout) ->
+    mysqlerl_connection:sql_query(Ref, "COMMIT", Timeout);
+commit(Ref, rollback, Timeout) ->
+    mysqlerl_connection:sql_query(Ref, "ROLLBACK", Timeout).
+
+%% Arguments:
+%%     Host = string()
+%%     Port = integer()
+%%     Database = string()
+%%     User = string()
+%%     Password = string()
+%%     Options = list()
+%%
+%% Returns:
+%%     {ok, Ref} | {error, Reason}
+%%     Ref = connection_reference()
+connect(Host, Port, Database, User, Password, Options) ->
+    mysqlerl_connection_sup:connect(Host, Port, Database,
+                                    User, Password, Options).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%
+%% Returns:
+%%     ok | {error, Reason}
+disconnect(Ref) ->
+    mysqlerl_connection:stop(Ref).
+
+describe_table(Ref, Table) ->
+    describe_table(Ref, Table, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Table = string()
+%%     Timeout = time_out()
+%%
+%% Returns:
+%%     {ok, Description} | {error, Reason}
+%%     Description = [{col_name(), odbc_data_type()}]
+describe_table(_Ref, _Table, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+first(Ref) ->
+    first(Ref, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+first(_Ref, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+last(Ref) ->
+    last(Ref, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+last(_Ref, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+next(Ref) ->
+    next(Ref, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+next(_Ref, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+prev(Ref) ->
+    prev(Ref, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+prev(_Ref, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+select_count(Ref, SQLQuery) ->
+    select_count(Ref, SQLQuery, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     SQLQuery = string()
+%%     Timeout = time_out()
+%% Returns:
+%%     {ok, NrRows} | {error, Reason}
+%%     NrRows = n_rows()
+select_count(_Ref, _SQLQuery, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+select(Ref, Pos, N) ->
+    select(Ref, Pos, N, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     Pos = integer()
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+select(_Ref, _Pos, _N, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+param_query(Ref, SQLQuery, Params) ->
+    param_query(Ref, SQLQuery, Params, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     SQLQuery = string()
+%%     Params = [{odbc_data_type(), [value()]}]
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+param_query(_Ref, _SQLQuery, _Params, _Timeout) ->
+    ?NOTIMPLEMENTED.
+
+sql_query(Ref, SQLQuery) ->
+    sql_query(Ref, SQLQuery, infinity).
+
+%% Arguments:
+%%     Ref = connection_reference()
+%%     SQLQuery = string()
+%%     Timeout = time_out()
+%% Returns:
+%%     {selected, ColNames, Rows} | {error, Reason}
+%%     Rows = rows()
+sql_query(_Ref, _SQLQuery, _Timeout) ->
+    ?NOTIMPLEMENTED.
diff --git a/src/mysqlerl_app.erl b/src/mysqlerl_app.erl
new file mode 100644
index 0000000..6be4007
--- /dev/null
+++ b/src/mysqlerl_app.erl
@@ -0,0 +1,19 @@
+-module(mysqlerl_app).
+-author('bjc@kublai.com').
+
+-behavior(application).
+-behavior(supervisor).
+
+-export([start/2, stop/1, init/1]).
+
+start(normal, []) ->
+    supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+stop([]) ->
+    ok.
+
+init([]) ->
+    ConnectionSup = {mysqlerl_connection_sup, {mysqlerl_connection_sup, start_link, []},
+                     permanent, infinity, supervisor, [mysqlerl_connection_sup]},
+    {ok, {{one_for_one, 10, 5},
+          [ConnectionSup]}}.
diff --git a/src/mysqlerl_connection.erl b/src/mysqlerl_connection.erl
new file mode 100644
index 0000000..aa73d23
--- /dev/null
+++ b/src/mysqlerl_connection.erl
@@ -0,0 +1,75 @@
+-module(mysqlerl_connection).
+-author('bjc@kublai.com').
+
+-behavior(gen_server).
+
+-export([start_link/6, stop/1, sql_query/3, testmsg/1]).
+
+-export([init/1, terminate/2, code_change/3,
+         handle_call/3, handle_cast/2, handle_info/2]).
+
+-record(state, {ref}).
+-record(port_closed, {reason}).
+-record(sql_query, {q}).
+
+start_link(Host, Port, Database, User, Password, Options) ->
+    gen_server:start_link(?MODULE, [Host, Port, Database,
+                                    User, Password, Options], []).
+
+stop(Pid) ->
+    gen_server:cast(Pid, stop).
+
+sql_query(Pid, Query, Timeout) ->
+    gen_server:call(Pid, #sql_query{q = Query}, Timeout).
+
+testmsg(Pid) ->
+    gen_server:call(Pid, {test, "SELECT COUNT(*) FROM user;"}).
+
+init([Host, Port, Database, User, Password, Options]) ->
+    process_flag(trap_exit, true),
+    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}]),
+    {ok, #state{ref = Ref}}.
+
+terminate(#port_closed{reason = Reason}, #state{ref = Ref}) ->
+    io:format("DEBUG: mysqlerl connection ~p shutting down (~p).~n",
+              [Ref, Reason]),
+    ok;
+terminate(Reason, State) ->
+    port_close(State#state.ref),
+    io:format("DEBUG: got terminate: ~p~n", [Reason]),
+    ok.
+
+code_change(_OldVsn, State, _Extra) ->
+    {ok, State}.
+
+handle_call({test, Str}, _From, #state{ref = Ref} = State) ->
+    io:format("DEBUG: got test message: ~p~n", [Str]),
+    port_command(Ref, Str),
+    receive
+        {Ref, {data, Res}} ->
+            {reply, {ok, Res}, State};
+        Other ->
+            error_logger:warning_msg("Got unknown message: ~p~n", [Other])
+    end;
+handle_call(Request, From, State) ->
+    io:format("DEBUG: got unknown call from ~p: ~p~n", [From, Request]),
+    {noreply, State}.
+
+handle_cast(stop, State) ->
+    {stop, normal, State}.
+
+handle_info({'EXIT', _Ref, Reason}, State) ->
+    {stop, #port_closed{reason = Reason}, State};
+handle_info(Info, State) ->
+    io:format("DEBUG: got unknown info: ~p~n", [Info]),
+    {noreply, State}.
+
+helper() ->
+    case code:priv_dir(mysqlerl) of
+        PrivDir when is_list(PrivDir) -> ok;
+        {error, bad_name} -> PrivDir = filename:join(["..", "priv"])
+    end,
+    filename:join([PrivDir, "mysqlerl"]).
diff --git a/src/mysqlerl_connection_sup.erl b/src/mysqlerl_connection_sup.erl
new file mode 100644
index 0000000..4aa3fc6
--- /dev/null
+++ b/src/mysqlerl_connection_sup.erl
@@ -0,0 +1,29 @@
+-module(mysqlerl_connection_sup).
+-author('bjc@kublai.com').
+
+-behavior(supervisor).
+
+-export([start_link/0, connect/6, random_child/0]).
+
+-export([init/1]).
+
+start_link() ->
+    supervisor:start_link({local, ?MODULE}, ?MODULE, []).
+
+connect(Host, Port, Database, User, Password, Options) ->
+    supervisor:start_child(?MODULE, [Host, Port, Database, User, Password, Options]).
+
+random_child() ->
+    case get_pids() of
+        []   -> {error, no_connections};
+        Pids -> lists:nth(erlang:phash(now(), length(Pids)), Pids)
+    end.
+
+init([]) ->
+    Connection = {undefined, {mysqlerl_connection, start_link, []},
+                  transient, 5, worker, [mysqlerl_connection]},
+    {ok, {{simple_one_for_one, 10, 5},
+          [Connection]}}.
+
+get_pids() ->
+    [Pid || {_Id, Pid, _Type, _Modules} <- supervisor:which_children(?MODULE)].