src/mod_magnet_cache.c

   1 #include "first.h"
   2
   3 #include "mod_magnet_cache.h"
   4 #include "stat_cache.h"
   5
   6 #include <stdlib.h>
   7 #include <time.h>
   8 #include <assert.h>
   9
  10 #include <lualib.h>
  11 #include <lauxlib.h>
  12
  13 static script *script_init() {
  14         script *sc;
  15
  16         sc = calloc(1, sizeof(*sc));
  17         sc->name = buffer_init();
  18         sc->etag = buffer_init();
  19
  20         return sc;
  21 }
  22
  23 static void script_free(script *sc) {
  24         if (!sc) return;
  25
  26         lua_pop(sc->L, 1); /* the function copy */
  27
  28         buffer_free(sc->name);
  29         buffer_free(sc->etag);
  30
  31         lua_close(sc->L);
  32
  33         free(sc);
  34 }
  35
  36 script_cache *script_cache_init() {
  37         script_cache *p;
  38
  39         p = calloc(1, sizeof(*p));
  40
  41         return p;
  42 }
  43
  44 void script_cache_free(script_cache *p) {
  45         size_t i;
  46
  47         if (!p) return;
  48
  49         for (i = 0; i < p->used; i++) {
  50                 script_free(p->ptr[i]);
  51         }
  52
  53         free(p->ptr);
  54
  55         free(p);
  56 }
  57
  58 lua_State *script_cache_get_script(server *srv, connection *con, script_cache *cache, buffer *name) {
  59         size_t i;
  60         script *sc = NULL;
  61         stat_cache_entry *sce;
  62
  63         for (i = 0; i < cache->used; i++) {
  64                 sc = cache->ptr[i];
  65
  66                 if (buffer_is_equal(name, sc->name)) {
  67                         sc->last_used = time(NULL);
  68
  69                         /* oops, the script failed last time */
  70
  71                         if (lua_gettop(sc->L) == 0) break;
  72                         force_assert(lua_gettop(sc->L) == 1);
  73
  74                         if (HANDLER_ERROR == stat_cache_get_entry(srv, con, sc->name, &sce)) {
  75                                 lua_pop(sc->L, 1); /* pop the old function */
  76                                 break;
  77                         }
  78
  79                         if (!buffer_is_equal(sce->etag, sc->etag)) {
  80                                 /* the etag is outdated, reload the function */
  81                                 lua_pop(sc->L, 1);
  82                                 break;
  83                         }
  84
  85                         force_assert(lua_isfunction(sc->L, -1));
  86
  87                         return sc->L;
  88                 }
  89
  90                 sc = NULL;
  91         }
  92
  93         /* if the script was script already loaded but either got changed or
  94          * failed to load last time */
  95         if (sc == NULL) {
  96                 sc = script_init();
  97
  98                 if (cache->size == 0) {
  99                         cache->size = 16;
 100                         cache->ptr = malloc(cache->size * sizeof(*(cache->ptr)));
 101                 } else if (cache->used == cache->size) {
 102                         cache->size += 16;
 103                         cache->ptr = realloc(cache->ptr, cache->size * sizeof(*(cache->ptr)));
 104                 }
 105
 106                 cache->ptr[cache->used++] = sc;
 107
 108                 buffer_copy_buffer(sc->name, name);
 109
 110                 sc->L = luaL_newstate();
 111                 luaL_openlibs(sc->L);
 112         }
 113
 114         sc->last_used = time(NULL);
 115
 116         if (0 != luaL_loadfile(sc->L, name->ptr)) {
 117                 /* oops, an error, return it */
 118                 return sc->L;
 119         }
 120
 121         if (HANDLER_GO_ON == stat_cache_get_entry(srv, con, sc->name, &sce)) {
 122                 buffer_copy_buffer(sc->etag, sce->etag);
 123         }
 124
 125         force_assert(lua_isfunction(sc->L, -1));
 126
 127         return sc->L;
 128 }