[ovs-dev,RFC,01/10] expr.c: Use expr_destroy and expr_clone instead of free and xmemdup.

diff --git a/lib/expr.c b/lib/expr.c
index e3f6bb892..5fc6c1ce9 100644
--- a/lib/expr.c
+++ b/lib/expr.c
@@ -186,7 +186,7 @@  expr_combine(enum expr_type type, struct expr *a, struct expr *b)
     } else if (a->type == type) {
         if (b->type == type) {
             ovs_list_splice(&a->andor, b->andor.next, &b->andor);
-            free(b);
+            expr_destroy(b);
         } else {
             ovs_list_push_back(&a->andor, &b->node);
         }
@@ -210,7 +210,7 @@  expr_insert_andor(struct expr *andor, struct expr *before, struct expr *new)
             /* Conjunction junction, what's your function? */
         }
         ovs_list_splice(&before->node, new->andor.next, &new->andor);
-        free(new);
+        expr_destroy(new);
     } else {
         ovs_list_insert(&before->node, &new->node);
     }
@@ -276,11 +276,11 @@  expr_fix_andor(struct expr *expr, bool short_circuit)
 
     if (ovs_list_is_short(&expr->andor)) {
         if (ovs_list_is_empty(&expr->andor)) {
-            free(expr);
+            expr_destroy(expr);
             return expr_create_boolean(!short_circuit);
         } else {
-            sub = expr_from_node(ovs_list_front(&expr->andor));
-            free(expr);
+            sub = expr_from_node(ovs_list_pop_front(&expr->andor));
+            expr_destroy(expr);
             return sub;
         }
     } else {
@@ -2096,7 +2096,7 @@  expr_simplify_relational(struct expr *expr)
      * and similarly for "tcp.dst <= 1234". */
     struct expr *new = NULL;
     if (eq) {
-        new = xmemdup(expr, sizeof *expr);
+        new = expr_clone(expr);
         new->cmp.relop = EXPR_R_EQ;
     }
 
@@ -2105,7 +2105,7 @@  expr_simplify_relational(struct expr *expr)
          z = bitwise_scan(value, sizeof *value, lt, z + 1, end)) {
         struct expr *e;
 
-        e = xmemdup(expr, sizeof *expr);
+        e = expr_clone(expr);
         e->cmp.relop = EXPR_R_EQ;
         bitwise_toggle_bit(&e->cmp.value, sizeof e->cmp.value, z);
         bitwise_zero(&e->cmp.value, sizeof e->cmp.value, start, z - start);
@@ -2324,7 +2324,7 @@  crush_and_string(struct expr *expr, const struct expr_symbol *symbol)
                 expr_destroy(expr);
                 return new;
             }
-            free(new);
+            expr_destroy(new);
             break;
         case EXPR_T_CONDITION:
             OVS_NOT_REACHED();
@@ -2463,14 +2463,14 @@  crush_and_numeric(struct expr *expr, const struct expr_symbol *symbol)
                 expr_destroy(sub);
             }
         }
-        free(disjuncts);
-        free(expr);
+        expr_destroy(disjuncts);
+        expr_destroy(expr);
         if (ovs_list_is_empty(&or->andor)) {
-            free(or);
+            expr_destroy(or);
             return expr_create_boolean(false);
         } else if (ovs_list_is_short(&or->andor)) {
             struct expr *cmp = expr_from_node(ovs_list_pop_front(&or->andor));
-            free(or);
+            expr_destroy(or);
             return cmp;
         } else {
             return crush_cmps(or, symbol);
@@ -2517,15 +2517,15 @@  crush_and_numeric(struct expr *expr, const struct expr_symbol *symbol)
         }
         expr_destroy(as);
         expr_destroy(bs);
-        free(new);
+        expr_destroy(new);
 
         if (ovs_list_is_empty(&or->andor)) {
             expr_destroy(expr);
-            free(or);
+            expr_destroy(or);
             return expr_create_boolean(false);
         } else if (ovs_list_is_short(&or->andor)) {
             struct expr *cmp = expr_from_node(ovs_list_pop_front(&or->andor));
-            free(or);
+            expr_destroy(or);
             if (ovs_list_is_empty(&expr->andor)) {
                 expr_destroy(expr);
                 return crush_cmps(cmp, symbol);
@@ -2675,7 +2675,7 @@  expr_sort(struct expr *expr)
     qsort(subs, n, sizeof *subs, compare_expr_sort);
 
     ovs_list_init(&expr->andor);
-    free(expr);
+    expr_destroy(expr);
     expr = NULL;
 
     for (i = 0; i < n; ) {
@@ -2708,7 +2708,7 @@  expr_sort(struct expr *expr)
                     expr = crushed;
                     break;
                 } else {
-                    free(crushed);
+                    expr_destroy(crushed);
                 }
             } else {
                 expr = expr_combine(EXPR_T_AND, expr, crushed);
@@ -2754,8 +2754,8 @@  expr_normalize_and(struct expr *expr)
         }
     }
     if (ovs_list_is_short(&expr->andor)) {
-        struct expr *sub = expr_from_node(ovs_list_front(&expr->andor));
-        free(expr);
+        struct expr *sub = expr_from_node(ovs_list_pop_front(&expr->andor));
+        expr_destroy(expr);
         return sub;
     }
 
@@ -2813,7 +2813,7 @@  expr_normalize_or(struct expr *expr)
                     expr_destroy(expr);
                     return new;
                 }
-                free(new);
+                expr_destroy(new);
             } else {
                 expr_insert_andor(expr, next, new);
             }
@@ -2823,12 +2823,12 @@  expr_normalize_or(struct expr *expr)
         }
     }
     if (ovs_list_is_empty(&expr->andor)) {
-        free(expr);
+        expr_destroy(expr);
         return expr_create_boolean(false);
     }
     if (ovs_list_is_short(&expr->andor)) {
         struct expr *e = expr_from_node(ovs_list_pop_front(&expr->andor));
-        free(expr);
+        expr_destroy(expr);
         return e;
     }