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#include "stream.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <lauxlib.h>
#include <lua.h>
/// Creates and pushes new Stream into the Lua stack.
/// \param L Lua state to push to
/// \param fd File descriptor used by the Stream
/// \return TODO
int stream_push_new(lua_State * L, const int fd)
{
struct stream * s = lua_newuserdata(L, sizeof(struct stream));
memset(s, 0, sizeof(struct stream));
s->fd = fd;
if (1 == luaL_newmetatable(L, "stream"))
{
lua_pushliteral(L, "__gc");
lua_pushcfunction(L, stream_gc);
lua_rawset(L, -3);
lua_pushliteral(L, "__index");
lua_createtable(L, 0, 1);
lua_pushliteral(L, "read");
lua_pushcfunction(L, stream_read);
lua_rawset(L, -3);
lua_rawset(L, -3);
}
lua_setmetatable(L, -2);
return LUA_OK;
}
/// Metamethod to handle garbage collection of Stream userdata.
/// \param L Lua state in which Stream resides
/// \return Number of the results pushed to the stack; always zero in this case
int stream_gc(lua_State * L)
{
int n = lua_gettop(L);
if (1 != n)
{
lua_pushliteral(L, "Invalid number of arguments received");
return lua_error(L);
}
struct stream * s = lua_touserdata(L, -1);
if (NULL == s)
{
lua_pushliteral(L, "Missing stream argument");
return lua_error(L);
}
if (NULL != s->in.data)
{
free(s->in.data);
}
lua_pop(L, 1);
return 0;
}
/// Starts reading operation from a stream.
/// \param L Lua state in which Stream resides
/// \return Number of the results pushed to the stack
int stream_read(lua_State * L)
{
struct stream * s = lua_touserdata(L, -1);
if (NULL == s)
{
// TODO: Improve error handling and raising in steam_* lua_CFunctions
lua_pushliteral(L, "Missing stream argument");
return lua_error(L);
}
if (NULL == s->in.data)
{
void * buffer = malloc(1024);
if (NULL == buffer)
{
lua_pushliteral(L, "Could not allocate buffer for stream");
return lua_error(L);
}
s->in.data = buffer;
}
return stream_readk(L, LUA_OK, (lua_KContext) s); // Intentionally do not pop Stream that's on top of the stack.
}
/// Continuation function and core implementation of the reading operation from a stream.
/// \param L Lua state running reading operation
/// \param status TODO
/// \param ctx Address of the Stream that is being read
/// \param Number of the results pushed to the stack
int stream_readk(lua_State * L, int status, lua_KContext ctx)
{
struct stream * s = (struct stream *) ctx;
int length = read(s->fd, s->in.data, 1023); // TODO: Allow user to control amount of bytes being read.
if (-1 == length)
{
if (EWOULDBLOCK == errno || EAGAIN == errno)
{
lua_yieldk(L, 0, ctx, stream_readk);
}
else
{
lua_pop(L, 1);
lua_pushstring(L, strerror(errno));
return lua_error(L);
}
}
s->in.data[length] = 0;
s->in.length = length;
s->in.offset = 0;
lua_pushstring(L, s->in.data);
lua_remove(L, -2);
return 1;
}
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