# HG changeset patch
# User jbe
# Date 1428104305 -7200
# Node ID 5df424e743835542568c58dc06a20cfcab374cd5
# Parent  12950c28b73a78802a58d3c518b1925e848f6bf6
Work on support for non-blocking I/O

diff -r 12950c28b73a -r 5df424e74383 moonbridge.c
--- a/moonbridge.c	Mon Mar 30 00:44:18 2015 +0200
+++ b/moonbridge.c	Sat Apr 04 01:38:25 2015 +0200
@@ -2202,6 +2202,27 @@
   return 1;
 }
 
+static int moonbr_lua_tonatural(lua_State *L, int idx) {
+  int isnum;
+  lua_Number n;
+  n = lua_tonumberx(L, idx, &isnum);
+  if (isnum && n>=0 && n<INT_MAX && (lua_Number)(int)n == n) return n;
+  else return -1;
+}
+
+static int moonbr_lua_totimeval(lua_State *L, int idx, struct timeval *value) {
+  int isnum;
+  lua_Number n;
+  n = lua_tonumberx(L, idx, &isnum);
+  if (isnum && n>=0 && n<=100000000) {
+    value->tv_sec = n;
+    value->tv_usec = 1e6 * (n - value->tv_sec);
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
 /* Memory allocator that allows limiting memory consumption */
 static void *moonbr_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
   (void)ud;  /* not used */
@@ -2236,8 +2257,164 @@
   return ptr;
 }
 
+/* New function io.poll(...) */
+static int moonbr_io_poll(lua_State *L) {
+  int idx_tbl = 1;
+  int idx_timeout = 0;
+  int i;
+  int fd, isnum;
+  int nfds = 0;
+  fd_set readfds, writefds, exceptfds;
+  struct timeval timeout = {0, };
+  int status;
+  FD_ZERO(&readfds);
+  FD_ZERO(&writefds);
+  FD_ZERO(&exceptfds);
+  if (lua_type(L, 1) == LUA_TNUMBER) {
+    idx_timeout = 1;
+    idx_tbl = 2;
+  }
+  luaL_checktype(L, idx_tbl, LUA_TTABLE);
+  for (i=1; ; i++) {
+#if LUA_VERSION_NUM >= 503
+    if (lua_geti(L, idx_tbl, i) == LUA_TNIL) break;
+#else
+    lua_pushinteger(L, i);
+    lua_gettable(L, idx_tbl);
+    if (lua_isnil(L, -1)) break;
+#endif
+    fd = lua_tointegerx(L, -1, &isnum);
+    if (!isnum) luaL_error(L, "File descriptor is not an integer");
+    FD_SET(fd, &readfds);
+    if (fd+1 > nfds) nfds = fd+1;
+    lua_pop(L, 1);
+  }
+  if (!idx_timeout && lua_type(L, 2) == LUA_TNUMBER) {
+    idx_timeout = 2;
+    idx_tbl = 3;
+  } else {
+    idx_tbl = 2;
+  }
+  luaL_checktype(L, idx_tbl, LUA_TTABLE);
+  for (i=1; ; i++) {
+#if LUA_VERSION_NUM >= 503
+    if (lua_geti(L, idx_tbl, i) == LUA_TNIL) break;
+#else
+    lua_pushinteger(L, i);
+    lua_gettable(L, idx_tbl);
+    if (lua_isnil(L, -1)) break;
+#endif
+    fd = lua_tointegerx(L, -1, &isnum);
+    if (!isnum) luaL_error(L, "File descriptor is not an integer");
+    FD_SET(fd, &writefds);
+    if (fd+1 > nfds) nfds = fd+1;
+    lua_pop(L, 1);
+  }
+  lua_pop(L, 2);
+  if (!idx_timeout && !lua_isnoneornil(L, 3)) idx_timeout = 3;
+  if (idx_timeout) {
+    luaL_argcheck(
+      L,
+      moonbr_lua_totimeval(L, idx_timeout, &timeout),
+      idx_timeout,
+      "not a valid timeout"
+    );
+  }
+  status = select(nfds, &readfds, &writefds, &exceptfds, &timeout);
+  if (status == -1) {
+    if (errno == EINTR) {
+      lua_pushboolean(L, 0);
+    } else {
+      char errmsg[MOONBR_MAXSTRERRORLEN];
+      strerror_r(errno, errmsg, MOONBR_MAXSTRERRORLEN);  /* use thread-safe call in case child created threads */
+      luaL_error(L, "Unexpected error during \"select\" system call: %s", errmsg);
+    }
+  } else if (status == 0) {
+    lua_pushboolean(L, 0);
+  } else {
+    lua_pushboolean(L, 1);
+  }
+  return 1;
+}
+
+/* New method for Lua file objects: get file descriptor */
+static int moonbr_io_getfd(lua_State *L) {
+  luaL_Stream *stream;
+  stream = luaL_checkudata(L, 1, LUA_FILEHANDLE);
+  if (!stream->closef) luaL_error(L, "attempt to use a closed file");
+  lua_pushinteger(L, fileno(stream->f));
+  return 1;
+}
+
+/* New method for Lua file objects: check if non-blocking reading is possible */
+static int moonbr_io_pending(lua_State *L) {
+  luaL_Stream *stream;
+  FILE *file;
+  int fd, flags, chr;
+  stream = luaL_checkudata(L, 1, LUA_FILEHANDLE);
+  if (!stream->closef) luaL_error(L, "attempt to use a closed file");
+  file = stream->f;
+  flockfile(file);
+  fd = fileno_unlocked(file);
+  if (ferror(file) || feof(file)) {
+    funlockfile(file);
+    lua_pushboolean(L, 1);
+    return 1;
+  }
+  flags = fcntl(fd, F_GETFL, 0);
+  if (flags == -1) goto moonbr_io_pending_error;
+  if (fcntl(fd, F_SETFL, flags | O_NONBLOCK) == -1) goto moonbr_io_pending_error;
+  chr = getc_unlocked(file);
+  lua_pushboolean(L, 1);
+  if (chr == EOF) {
+    if (ferror(file) && errno == EAGAIN) {
+      clearerr_unlocked(file);
+      lua_pushboolean(L, 0);
+    }
+  } else {
+    if (ungetc(chr, file) == EOF) goto moonbr_io_pending_error;
+  }
+  if (fcntl(fd, F_SETFL, flags) == -1) goto moonbr_io_pending_error;
+  funlockfile(file);
+  return 1;
+  moonbr_io_pending_error:
+  funlockfile(file);
+  {
+    char errmsg[MOONBR_MAXSTRERRORLEN];
+    strerror_r(errno, errmsg, MOONBR_MAXSTRERRORLEN);  /* use thread-safe call in case child created threads */
+    luaL_error(L, "Unexpected error in method \"pending\" of FILE handle: %s", errmsg);
+  }
+  return 0;
+}
+
+/* New method for Lua file objects: set blocking or non-blocking I/O */
+static int moonbr_io_setblocking(lua_State *L) {
+  luaL_Stream *stream;
+  int blocking;
+  int fd, flags;
+  stream = luaL_checkudata(L, 1, LUA_FILEHANDLE);
+  luaL_checktype(L, 2, LUA_TBOOLEAN);
+  blocking = lua_toboolean(L, 2);
+  if (!stream->closef) luaL_error(L, "attempt to use a closed file");
+  fd = fileno_unlocked(stream->f);
+  flags = fcntl(fd, F_GETFL, 0);
+  if (flags == -1) goto moonbr_io_setblocking_error;
+  if (blocking) flags &= ~ O_NONBLOCK;
+  else flags |= O_NONBLOCK;
+  if (fcntl(fd, F_SETFL, flags) == -1) goto moonbr_io_setblocking_error;
+  lua_pushboolean(L, 1);
+  return 1;
+  moonbr_io_setblocking_error:
+  {
+    char errmsg[MOONBR_MAXSTRERRORLEN];
+    strerror_r(errno, errmsg, MOONBR_MAXSTRERRORLEN);  /* use thread-safe call in case child created threads */
+    luaL_error(L, "Unexpected error in method \"setblocking\" of FILE handle: %s", errmsg);
+  }
+  return 0;
+}
+
 /* New method for Lua file objects: read until terminator or length exceeded */
-static int moonbr_readuntil(lua_State *L) {
+static int moonbr_io_readuntil(lua_State *L) {
   luaL_Stream *stream;
   FILE *file;
   const char *terminatorstr;
@@ -2276,27 +2453,6 @@
   return 1;
 }
 
-static int moonbr_lua_tonatural(lua_State *L, int idx) {
-  int isnum;
-  lua_Number n;
-  n = lua_tonumberx(L, idx, &isnum);
-  if (isnum && n>=0 && n<INT_MAX && (lua_Number)(int)n == n) return n;
-  else return -1;
-}
-
-static int moonbr_lua_totimeval(lua_State *L, int idx, struct timeval *value) {
-  int isnum;
-  lua_Number n;
-  n = lua_tonumberx(L, idx, &isnum);
-  if (isnum && n>=0 && n<=100000000) {
-    value->tv_sec = n;
-    value->tv_usec = 1e6 * (n - value->tv_sec);
-    return 1;
-  } else {
-    return 0;
-  }
-}
-
 static int moonbr_timeout(lua_State *L) {
   struct itimerval oldval;
   if (lua_isnoneornil(L, 1) && lua_isnoneornil(L, 2)) {
@@ -2764,12 +2920,22 @@
 #ifdef MOONBR_LUA_CPATH
     moonbr_modify_path(L, "cpath", MOONBR_LUA_CPATH);
 #endif
+    lua_getglobal(L, "io");
+    lua_pushcfunction(L, moonbr_io_poll);
+    lua_setfield(L, -2, "poll");
+    lua_pop(L, 1);
     if (luaL_newmetatable(L, LUA_FILEHANDLE)) {
       moonbr_log(LOG_CRIT, "Lua metatable LUA_FILEHANDLE does not exist");
       moonbr_terminate_error();
     }
     lua_getfield(L, -1, "__index");
-    lua_pushcfunction(L, moonbr_readuntil);
+    lua_pushcfunction(L, moonbr_io_getfd);
+    lua_setfield(L, -2, "getfd");
+    lua_pushcfunction(L, moonbr_io_pending);
+    lua_setfield(L, -2, "pending");
+    lua_pushcfunction(L, moonbr_io_setblocking);
+    lua_setfield(L, -2, "setblocking");
+    lua_pushcfunction(L, moonbr_io_readuntil);
     lua_setfield(L, -2, "readuntil");
     lua_pop(L, 2);
     lua_pushcfunction(L, moonbr_timeout);