[MEDIUM] memory: update pool_free2() to support NULL pointers

In order to make pool usage more convenient, let pool_free2()
support NULL pointers by doing nothing, just like the standard
free(3) call does.

The various call places have been updated to remove the now
useless checks.
diff --git a/include/common/memory.h b/include/common/memory.h
index 835d79d..765351c 100644
--- a/include/common/memory.h
+++ b/include/common/memory.h
@@ -2,7 +2,7 @@
   include/common/memory.h
   Memory management definitions..
 
-  Copyright (C) 2000-2007 Willy Tarreau - w@1wt.eu
+  Copyright (C) 2000-2008 Willy Tarreau - w@1wt.eu
   
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
@@ -186,13 +186,16 @@
  * is written in the beginning of the memory area, so
  * there's no need for any carrier cell. This implies
  * that each memory area is at least as big as one
- * pointer.
+ * pointer. Just like with the libc's free(), nothing
+ * is done if <ptr> is NULL.
  */
 #define pool_free2(pool, ptr)                           \
 ({                                                      \
-        *(void **)ptr = (void *)pool->free_list;        \
-        pool->free_list = (void *)ptr;                  \
-        pool->used--;                                   \
+        if (likely((ptr) != NULL)) {                    \
+                *(void **)ptr = (void *)pool->free_list;\
+                pool->free_list = (void *)ptr;          \
+                pool->used--;                           \
+        }                                               \
 })
 
 
diff --git a/src/appsession.c b/src/appsession.c
index b3f2c76..45050b5 100644
--- a/src/appsession.c
+++ b/src/appsession.c
@@ -148,13 +148,9 @@
 }/* end match_str */
 
 void destroy(appsess *temp1) {
-    if (temp1->sessid)
 	pool_free2(apools.sessid, temp1->sessid);
-
-    if (temp1->serverid)
 	pool_free2(apools.serverid, temp1->serverid);
-
-    pool_free2(pool2_appsess, temp1);
+	pool_free2(pool2_appsess, temp1);
 } /* end destroy */
 
 void appsession_cleanup( void )
diff --git a/src/client.c b/src/client.c
index 502ee97..a4d5265 100644
--- a/src/client.c
+++ b/src/client.c
@@ -433,17 +433,13 @@
 
 	/* Error unrolling */
  out_fail_rep:
-	if (s->req)
-		pool_free2(pool2_buffer, s->req);
+	pool_free2(pool2_buffer, s->req);
  out_fail_req:
-	if (txn->hdr_idx.v != NULL)
-		pool_free2(p->hdr_idx_pool, txn->hdr_idx.v);
+	pool_free2(p->hdr_idx_pool, txn->hdr_idx.v);
  out_fail_idx:
-	if (txn->rsp.cap != NULL)
-		pool_free2(p->rsp_cap_pool, txn->rsp.cap);
+	pool_free2(p->rsp_cap_pool, txn->rsp.cap);
  out_fail_rspcap:
-	if (txn->req.cap != NULL)
-		pool_free2(p->req_cap_pool, txn->req.cap);
+	pool_free2(p->req_cap_pool, txn->req.cap);
  out_fail_reqcap:
  out_free_task:
 	pool_free2(pool2_task, t);
diff --git a/src/session.c b/src/session.c
index c27ef75..ceef0b7 100644
--- a/src/session.c
+++ b/src/session.c
@@ -47,57 +47,39 @@
 		sess_change_server(s, NULL);
 	}
 
-	if (s->req)
-		pool_free2(pool2_buffer, s->req);
-	if (s->rep)
-		pool_free2(pool2_buffer, s->rep);
+	pool_free2(pool2_buffer, s->req);
+	pool_free2(pool2_buffer, s->rep);
 
 	if (fe) {
-		if (txn->hdr_idx.v != NULL)
-			pool_free2(fe->hdr_idx_pool, txn->hdr_idx.v);
+		pool_free2(fe->hdr_idx_pool, txn->hdr_idx.v);
 
 		if (txn->rsp.cap != NULL) {
 			struct cap_hdr *h;
-			for (h = fe->rsp_cap; h; h = h->next) {
-				if (txn->rsp.cap[h->index] != NULL)
-					pool_free2(h->pool, txn->rsp.cap[h->index]);
-			}
+			for (h = fe->rsp_cap; h; h = h->next)
+				pool_free2(h->pool, txn->rsp.cap[h->index]);
 			pool_free2(fe->rsp_cap_pool, txn->rsp.cap);
 		}
 		if (txn->req.cap != NULL) {
 			struct cap_hdr *h;
-			for (h = fe->req_cap; h; h = h->next) {
-				if (txn->req.cap[h->index] != NULL)
-					pool_free2(h->pool, txn->req.cap[h->index]);
-			}
+			for (h = fe->req_cap; h; h = h->next)
+				pool_free2(h->pool, txn->req.cap[h->index]);
 			pool_free2(fe->req_cap_pool, txn->req.cap);
 		}
 	}
-	if (txn->uri)
-		pool_free2(pool2_requri, txn->uri);
-	if (txn->cli_cookie)
-		pool_free2(pool2_capture, txn->cli_cookie);
-	if (txn->srv_cookie)
-		pool_free2(pool2_capture, txn->srv_cookie);
-
+	pool_free2(pool2_requri, txn->uri);
+	pool_free2(pool2_capture, txn->cli_cookie);
+	pool_free2(pool2_capture, txn->srv_cookie);
 	pool_free2(pool2_session, s);
 
 	/* We may want to free the maximum amount of pools if the proxy is stopping */
 	if (fe && unlikely(fe->state == PR_STSTOPPED)) {
-		if (pool2_buffer)
-			pool_flush2(pool2_buffer);
-		if (fe->hdr_idx_pool)
-			pool_flush2(fe->hdr_idx_pool);
-		if (pool2_requri)
-			pool_flush2(pool2_requri);
-		if (pool2_capture)
-			pool_flush2(pool2_capture);
-		if (pool2_session)
-			pool_flush2(pool2_session);
-		if (fe->req_cap_pool)
-			pool_flush2(fe->req_cap_pool);
-		if (fe->rsp_cap_pool)
-			pool_flush2(fe->rsp_cap_pool);
+		pool_flush2(pool2_buffer);
+		pool_flush2(fe->hdr_idx_pool);
+		pool_flush2(pool2_requri);
+		pool_flush2(pool2_capture);
+		pool_flush2(pool2_session);
+		pool_flush2(fe->req_cap_pool);
+		pool_flush2(fe->rsp_cap_pool);
 	}
 }