lua filter saving and reusing

2 files changed, 111 insertions, 2 deletions

diff --git a/lua/filter.c b/lua/filter.c
index 9d12fb16..fa005354 100644
--- a/lua/filter.c
+++ b/lua/filter.c
@@ -1,4 +1,5 @@
 #include "nest/bird.h"
+#include "conf/conf.h"
 #include "filter/filter.h"
 #include "lua.h"
 
@@ -8,12 +9,85 @@
 
 /* Docs: http://pgl.yoyo.org/luai/i/luaL_dostring */
 
-struct f_val filter_lua_chunk(const char *chunk, struct rte **e, struct rta *a, struct ea_list **ea, struct linpool *lp) {
+struct lua_new_filter_writer_data {
+  struct lua_filter_chunk *first, *last;
+};
+
+static int lua_new_filter_writer(lua_State *L UNUSED, const void *p, size_t sz, void *ud) {
+  struct lua_new_filter_writer_data *d = ud;
+  struct lua_filter_chunk *cur = cfg_allocz(sizeof(struct lua_filter_chunk));
+
+  cur->size = sz;
+  cur->chunk = cfg_alloc(sz);
+  memcpy(cur->chunk, p, sz);
+
+  if (d->last)
+    d->last = d->last->next = cur;
+  else
+    d->last = d->first = cur;
+
+  return 0;
+}
+
+struct filter * lua_new_filter(struct f_inst *inst) {
+  struct filter *f = cfg_alloc(sizeof(struct filter));
+  f->name = NULL;
+  f->type = FILTER_LUA;
+
+  struct f_val string = f_eval(inst, cfg_mem);
+  if (string.type != T_STRING) {
+    cf_error("Lua filter must be a string");
+    return NULL;
+  }
+
+  lua_State *L = luaL_newstate();
+  luaL_openlibs(L);
+  int loadres = luaL_loadstring(L, string.val.s);
+  switch (loadres) {
+    case LUA_ERRMEM:
+      lua_close(L);
+      cf_error("Memory allocation error occured when loading lua chunk");
+      return NULL;
+    case LUA_ERRSYNTAX:
+      {
+	const char *e = lua_tostring(L, -1);
+	char *ec = cfg_alloc(strlen(e) + 1);
+	strcpy(ec, e);
+	lua_close(L);
+	cf_error("Lua syntax error: %s", ec);
+	return NULL;
+      }
+    case 0: /* Everything OK */
+      break;
+  }
+
+  struct lua_new_filter_writer_data lnfwd = {};
+  lua_dump(L, lua_new_filter_writer, &lnfwd, 0); /* No error to handle */
+  lua_close(L);
+
+  f->lua_chunk = lnfwd.first;
+  return f;
+}
+
+static const char *lua_interpret_reader(lua_State *L UNUSED, void *ud, size_t *sz) {
+  struct lua_filter_chunk **cptr = ud;
+  if ((*cptr) == NULL)
+    return NULL;
+
+  *sz = (*cptr)->size;
+  void *out = (*cptr)->chunk;
+  *cptr = (*cptr)->next;
+  return out;
+}
+
+struct f_val lua_interpret(struct lua_filter_chunk *chunk, struct rte **e, struct rta **a, struct ea_list **ea, struct linpool *lp, int flags) {
   lua_State *L = luaL_newstate();
   luaL_openlibs(L);
   lua_bird_state *lbs = luaB_init(L, lp);
   luaB_push_route(L, *e);
-  int le = luaL_dostring(L, chunk);
+  struct lua_filter_chunk **rptr = &chunk;
+  lua_load(L, lua_interpret_reader, rptr, "", "b");
+  int le = lua_pcall(L, 0, LUA_MULTRET, 0);
   struct f_val out = F_VAL_VOID;
   if (le && lbs->exception) {
     out = F_VAL(T_RETURN, i, lbs->exception);
@@ -30,3 +104,32 @@ struct f_val filter_lua_chunk(const char *chunk, struct rte **e, struct rta *a,
   lua_close(L);
   return out;
 }
+
+int lua_filter_same(struct lua_filter_chunk *new, struct lua_filter_chunk *old) {
+  size_t npos = 0, opos = 0;
+  while (new && old) {
+    size_t nrem = new->size - npos;
+    size_t orem = old->size - opos;
+    size_t rem = MIN(nrem, orem);
+    if (memcmp(new->chunk + npos, old->chunk + opos, rem))
+      return 0;
+
+    npos += rem;
+    opos += rem;
+
+    if (npos == new->size) {
+      new = new->next;
+      npos = 0;
+    }
+
+    if (opos == old->size) {
+      old = old->next;
+      opos = 0;
+    }
+  }
+
+  if (!new && !old)
+    return 1;
+  else
+    return 0;
+}
diff --git a/lua/lua.h b/lua/lua.h
index 39582e2e..021f0ee8 100644
--- a/lua/lua.h
+++ b/lua/lua.h
@@ -2,6 +2,12 @@
 
 #include <lua.h>
 
+struct lua_filter_chunk {
+  size_t size;
+  void *chunk;
+  struct lua_filter_chunk *next;
+};
+
 typedef struct lua_bird_state {
   int exception;
 } lua_bird_state;