Add more expression evaluation goo.

diff --git a/includes/tree.h b/includes/tree.h
index e4a62841497ac5b283c2066f346c21f26c12c832..ffd909c8c6a4517ce69a128510552f184854bca4 100644 (file)
--- a/includes/tree.h
+++ b/includes/tree.h
@@ -53,35 +53,54 @@ typedef struct _pair {
 #define TREE_LIMIT             4
 #define TREE_DATA_EXPR         5
 
+/* A data buffer with a reference count. */
+struct buffer {
+       int refcnt;
+       char data [1];
+};
+
+/* XXX The mechanism by which data strings are returned is currently
+   XXX broken: rather than returning an ephemeral pointer, we create
+   XXX a reference to the data in the caller's space, which the caller
+   XXX then has to dereference - instead, the reference should be
+   XXX ephemeral by default and be made a persistent reference explicitly. */
+
 /* A string of data bytes, possibly accompanied by a larger buffer. */
 struct data_string {
-       unsigned char *data, *buffer;
+       struct buffer *buffer;
+       unsigned char *data;
        int len;
        int terminated;
 };
 
 /* Expression tree structure. */
 
+enum expr_op {
+       expr_none,
+       expr_match,
+       expr_check,
+       expr_equal,
+       expr_substring,
+       expr_suffix,
+       expr_concat,
+       expr_host_lookup,
+       expr_and,
+       expr_or,
+       expr_not,
+       expr_option,
+       expr_hardware,
+       expr_packet,
+       expr_const_data,
+       expr_extract_int8,
+       expr_extract_int16,
+       expr_extract_int32,
+       expr_const_int,
+       expr_exists,
+};
+
 struct expression {
-       enum {
-               expr_check,
-               expr_equal,
-               expr_substring,
-               expr_suffix,
-               expr_concat,
-               expr_host_lookup,
-               expr_and,
-               expr_or,
-               expr_not,
-               expr_option,
-               expr_hardware,
-               expr_packet,
-               expr_const_data,
-               expr_extract_int8,
-               expr_extract_int16,
-               expr_extract_int32,
-               expr_const_int,
-       } op;
+       int refcnt;
+       enum expr_op op;
        union {
                struct {
                        struct expression *expr;
@@ -103,13 +122,11 @@ struct expression {
                        struct expression *len;
                } packet;
                struct data_string const_data;
-               struct {
-                       struct expression *expr;
-                       struct expression *width;
-               } extract_int;
+               struct expression *extract_int;
                unsigned long const_int;
                struct expression *concat [2];
                struct dns_host_entry *host_lookup;
+               struct option *exists;
        } data;
        int flags;
 #      define EXPR_EPHEMERAL   1
@@ -117,26 +134,24 @@ struct expression {
 
 /* DNS host entry structure... */
 struct dns_host_entry {
-       char *hostname;
-       char *buffer;
-       int buf_len;
-       int data_len;
+       int refcnt;
        TIME timeout;
+       struct data_string data;
+       char hostname [1];
 };
 
-struct option_cache {
-       struct expression *expression;
-       struct option *option;
-};
-
+struct option_cache; /* forward */
 struct data_string; /* forward */
 struct packet; /* forward */
 struct option_state; /* forward */
+struct decoded_option_state; /* forward */
 enum statement_op; /* forward */
 
 struct universe {
        char *name;
-       struct data_string (*lookup_func) PROTO ((struct packet *, int));
+       int (*lookup_func)
+               PROTO ((struct data_string *,
+                       struct option_state *, int));
        void (*set_func) PROTO ((struct option_state *,
                                 struct option_cache *,
                                 enum statement_op));
@@ -150,3 +165,10 @@ struct option {
        struct universe *universe;
        unsigned char code;
 };
+
+enum expression_context {
+       context_any,
+       context_boolean,
+       context_data,
+       context_numeric
+};