Make Select a singleton

It's going to manipulate process-global signal state, so multiple
instances do not make sense.

src/examples/Makefile.am

@@ -29,7 +29,7 @@ termemu_LDADD = ../terminal/libmoshterminal.a ../util/libmoshutil.a ../statesync
 
 ntester_SOURCES = ntester.cc
 ntester_CPPFLAGS = -I$(srcdir)/../util -I$(srcdir)/../statesync -I$(srcdir)/../terminal -I$(srcdir)/../network -I$(srcdir)/../crypto -I../protobufs $(protobuf_CFLAGS)
-ntester_LDADD = ../statesync/libmoshstatesync.a ../terminal/libmoshterminal.a ../network/libmoshnetwork.a ../crypto/libmoshcrypto.a ../protobufs/libmoshprotos.a -lutil -lm $(protobuf_LIBS)
+ntester_LDADD = ../statesync/libmoshstatesync.a ../terminal/libmoshterminal.a ../network/libmoshnetwork.a ../crypto/libmoshcrypto.a ../protobufs/libmoshprotos.a ../util/libmoshutil.a -lutil -lm $(protobuf_LIBS)
 
 benchmark_SOURCES = benchmark.cc
 benchmark_CPPFLAGS = -I$(srcdir)/../util -I$(srcdir)/../statesync -I$(srcdir)/../terminal -I../protobufs -I$(srcdir)/../frontend -I$(srcdir)/../crypto -I$(srcdir)/../network $(STDDJB_CPPFLAGS) $(protobuf_CFLAGS)

src/examples/ntester.cc

@@ -58,7 +58,7 @@ int main( int argc, char *argv[] )
   fprintf( stderr, "Port bound is %d, key is %s\n", n->port(), n->get_key().c_str() );
 
   if ( server ) {
-    Select sel;
+    Select &sel = Select::get_instance();
     sel.add_fd( n->fd() );
     uint64_t last_num = n->get_remote_state_num();
     while ( true ) {
@@ -100,7 +100,7 @@ int main( int argc, char *argv[] )
       exit( 1 );
     }
 
-    Select sel;
+    Select &sel = Select::get_instance();
     sel.add_fd( STDIN_FILENO );
     sel.add_fd( n->fd() );
 

src/examples/parse.cc

@@ -122,7 +122,7 @@ void emulate_terminal( int fd )
 {
   Parser::UTF8Parser parser;
 
-  Select sel;
+  Select &sel = Select::get_instance();
   sel.add_fd( STDIN_FILENO );
   sel.add_fd( fd );
 

src/examples/termemu.cc

@@ -227,7 +227,7 @@ void emulate_terminal( int fd )
   /* open display */
   Terminal::Display display( true ); /* use TERM to initialize */
 
-  Select sel;
+  Select &sel = Select::get_instance();
   sel.add_fd( STDIN_FILENO );
   sel.add_fd( fd );
   sel.add_fd( signal_fd );

src/frontend/mosh-server.cc

@@ -479,7 +479,7 @@ void serve( int host_fd, Terminal::Complete &terminal, ServerConnection &network
   fatal_assert( sigfd_trap( SIGINT ) == 0 );
 
   /* prepare to poll for events */
-  Select sel;
+  Select &sel = Select::get_instance();
   sel.add_fd( network.fd() );
   sel.add_fd( host_fd );
   sel.add_fd( signal_fd );

src/frontend/stmclient.cc

@@ -299,7 +299,7 @@ void STMClient::main( void )
   main_init();
 
   /* prepare to poll for events */
-  Select sel;
+  Select &sel = Select::get_instance();
   sel.add_fd( network->fd() );
   sel.add_fd( STDIN_FILENO );
   sel.add_fd( signal_fd );

src/util/Makefile.am

@@ -2,7 +2,7 @@ AM_CXXFLAGS = $(WARNING_CXXFLAGS) $(PICKY_CXXFLAGS) $(HARDEN_CFLAGS) $(MISC_CXXF
 
 noinst_LIBRARIES = libmoshutil.a
 
-libmoshutil_a_SOURCES = locale_utils.cc locale_utils.h swrite.cc swrite.h dos_assert.h fatal_assert.h sigfd.h select.h
+libmoshutil_a_SOURCES = locale_utils.cc locale_utils.h swrite.cc swrite.h dos_assert.h fatal_assert.h sigfd.h select.h select.cc
 
 if !USE_LIBSTDDJB
   libmoshutil_a_SOURCES += sigfd.cc

src/util/select.cc

@@ -0,0 +1,21 @@
+/*
+    Mosh: the mobile shell
+    Copyright 2012 Keith Winstein
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "select.h"
+
+Select *Select::instance = NULL;

src/util/select.h

@@ -33,6 +33,17 @@ static fd_set dummy_fd_set;
 /* Convenience wrapper for select(2). */
 class Select {
 public:
+  static Select &get_instance( void ) {
+    // NB: not thread-safe
+    if ( !instance ) {
+      instance = new Select;
+    }
+    return *instance;
+  }
+
+private:
+  static Select *instance;
+
   Select()
     : max_fd( -1 )
 
@@ -47,6 +58,11 @@ public:
     FD_ZERO( &error_fds );
   }
 
+  /* not implemented */
+  Select( const Select & );
+  Select &operator=( const Select & );
+
+public:
   void add_fd( int fd )
   {
     if ( fd > max_fd ) {