src/event_buffer.c

   1 /* LuaEvent - Copyright (C) 2007 Thomas Harning <harningt@gmail.com>
   2  * Licensed as LGPL - See doc/COPYING for details */
   3
   4 #include "event_buffer.h"
   5 #include <lauxlib.h>
   6
   7 #define EVENT_BUFFER_MT "EVENT_BUFFER_MT"
   8
   9 #define BUFFER_ADD_CHECK_INPUT_FIRST 1
  10
  11 static le_buffer* event_buffer_get(lua_State* L, int idx) {
  12         return (le_buffer*)luaL_checkudata(L, idx, EVENT_BUFFER_MT);
  13 }
  14 static le_buffer* event_buffer_check(lua_State* L, int idx) {
  15         le_buffer* buf = (le_buffer*)luaL_checkudata(L, idx, EVENT_BUFFER_MT);
  16         if(!buf->buffer)
  17                 luaL_argerror(L, idx, "Attempt to use closed event_buffer object");
  18         return buf;
  19 }
  20 static int is_event_buffer(lua_State* L, int idx) {
  21         int ret;
  22         lua_getmetatable(L, idx);
  23         luaL_getmetatable(L, EVENT_BUFFER_MT);
  24         ret = lua_rawequal(L, -2, -1);
  25         lua_pop(L, 2);
  26         return ret;
  27 }
  28
  29 /* TODO: Use lightuserdata mapping to locate hanging object instances */
  30 static int event_buffer_push(lua_State* L, struct evbuffer* buffer) {
  31         le_buffer *buf = (le_buffer*)lua_newuserdata(L, sizeof(le_buffer));
  32         buf->buffer = buffer;
  33         luaL_getmetatable(L, EVENT_BUFFER_MT);
  34         lua_setmetatable(L, -2);
  35         return 1;
  36 }
  37
  38 static int event_buffer_push_new(lua_State* L) {
  39         return event_buffer_push(L, evbuffer_new());
  40 }
  41
  42 static int event_buffer_gc(lua_State* L) {
  43         le_buffer* buf = event_buffer_get(L, 1);
  44         if(buf->buffer) {
  45                 evbuffer_free(buf->buffer);
  46                 buf->buffer = NULL;
  47         }
  48         return 0;
  49 }
  50
  51 /* LUA: buffer:add(...)
  52         progressively adds items to the buffer
  53                 if arg[*] is string, treat as a string:format call
  54                 if arg[*] is a buffer, perform event_add_buffer
  55         returns number of bytes added
  56 */
  57 static int event_buffer_add(lua_State* L) {
  58         le_buffer* buf = event_buffer_check(L, 1);
  59         struct evbuffer* buffer = buf->buffer;
  60         int oldLength = EVBUFFER_LENGTH(buffer);
  61         int last = lua_gettop(L);
  62         int i;
  63         for(i = 2; i <= last; i++) {
  64                 if(!lua_isstring(L, i) && !is_event_buffer(L, i))
  65                         luaL_argerror(L, i, "Argument is not a string or buffer object");
  66 /* Optionally perform checks and data loading separately to avoid overfilling the buffer */
  67 #if BUFFER_ADD_CHECK_INPUT_FIRST
  68         }
  69         for(i = 2; i <= last; i++) {
  70 #endif
  71                 if(lua_isstring(L, i)) {
  72                         size_t len;
  73                         const char* data = lua_tolstring(L, i, &len);
  74                         if(0 != evbuffer_add(buffer, data, len))
  75                                 luaL_error(L, "Failed to add data to the buffer");
  76                 } else {
  77                         le_buffer* buf2 = event_buffer_check(L, i);
  78                         if(0 != evbuffer_add_buffer(buffer, buf2->buffer))
  79                                 luaL_error(L, "Failed to move buffer-data to the buffer");
  80                 }
  81         }
  82         lua_pushinteger(L, EVBUFFER_LENGTH(buffer) - oldLength);
  83         return 1;
  84 }
  85
  86 static int event_buffer_get_length(lua_State* L) {
  87         le_buffer* buf = event_buffer_check(L, 1);
  88         lua_pushinteger(L, EVBUFFER_LENGTH(buf->buffer));
  89         return 1;
  90 }
  91
  92 /* MAYBE: Could add caching */
  93 static int event_buffer_get_data(lua_State* L) {
  94         le_buffer* buf = event_buffer_check(L, 1);
  95         int begin, len;
  96         switch(lua_gettop(L)) {
  97         case 1:
  98                 /* Obtain full data */
  99                 begin = 0;
 100                 len = EVBUFFER_LENGTH(buf->buffer);
 101                 break;
 102         case 2:
 103                 begin = 0;
 104                 len = luaL_checkinteger(L, 2);
 105                 if(len > EVBUFFER_LENGTH(buf->buffer))
 106                         len = EVBUFFER_LENGTH(buf->buffer);
 107                 break;
 108         case 3:
 109         default:
 110                 begin = luaL_checkinteger(L, 2);
 111                 len = luaL_checkinteger(L, 3);
 112                 if(begin > EVBUFFER_LENGTH(buf->buffer))
 113                         begin = EVBUFFER_LENGTH(buf->buffer);
 114                 if(begin + len > EVBUFFER_LENGTH(buf->buffer))
 115                         len = EVBUFFER_LENGTH(buf->buffer) - begin;
 116                 break;
 117         }
 118         lua_pushlstring(L, (const char*)EVBUFFER_DATA(buf->buffer) + begin, len);
 119         return 1;
 120 }
 121
 122 static int event_buffer_drain(lua_State* L) {
 123         le_buffer* buf = event_buffer_check(L, 1);
 124         size_t len = luaL_checkinteger(L, 2);
 125         evbuffer_drain(buf->buffer, len);
 126         return 0;
 127 }
 128
 129 static luaL_Reg buffer_funcs[] = {
 130         {"add",event_buffer_add},
 131         {"length",event_buffer_get_length},
 132         {"get_data",event_buffer_get_data},
 133         {"drain",event_buffer_drain},
 134         {"close",event_buffer_gc},
 135         {NULL, NULL}
 136 };
 137 static luaL_Reg funcs[] = {
 138         {"new",event_buffer_push_new},
 139         {NULL, NULL}
 140 };
 141
 142 int event_buffer_register(lua_State* L) {
 143         luaL_newmetatable(L, EVENT_BUFFER_MT);
 144         lua_pushcfunction(L, event_buffer_gc);
 145         lua_setfield(L, -2, "__gc");
 146         lua_newtable(L);
 147         luaL_register(L, NULL, buffer_funcs);
 148         lua_setfield(L, -2, "__index");
 149         lua_pop(L, 1);
 150
 151         luaL_register(L, "luaevent.core.buffer", funcs);
 152         return 0;
 153 }