Use container_of() to get main struct from node

Direct casts hardwire the assumption that node
is always first member of struct.

diff --git a/src/cluster.c b/src/cluster.c
index ead16d549be327e25d676e60b5c0a6d6107b50c4..c975d6f9cda7feb33742ce9ed502e1058904e79e 100644 (file)
--- a/src/cluster.c
+++ b/src/cluster.c
@@ -91,7 +91,7 @@ check_valid_partcount(int n)
 static int cluster_name_cmp(uintptr_t val, struct AANode *node)
 {
        const char *name = (const char *)val;
-       const ProxyCluster *cluster = (ProxyCluster *)node;
+       const ProxyCluster *cluster = container_of(node, ProxyCluster, node);
 
        return strcmp(name, cluster->name);
 }
@@ -99,14 +99,14 @@ static int cluster_name_cmp(uintptr_t val, struct AANode *node)
 static int conn_cstr_cmp(uintptr_t val, struct AANode *node)
 {
        const char *name = (const char *)val;
-       const ProxyConnection *conn = (ProxyConnection *)node;
+       const ProxyConnection *conn = container_of(node, ProxyConnection, node);
 
        return strcmp(name, conn->connstr);
 }
 
 static void conn_free(struct AANode *node, void *arg)
 {
-       ProxyConnection *conn = (ProxyConnection *)node;
+       ProxyConnection *conn = container_of(node, ProxyConnection, node);
 
        aatree_destroy(&conn->userstate_tree);
        if (conn->res)
@@ -117,14 +117,14 @@ static void conn_free(struct AANode *node, void *arg)
 static int state_user_cmp(uintptr_t val, struct AANode *node)
 {
        const char *name = (const char *)val;
-       const ProxyConnectionState *state = (ProxyConnectionState *)node;
+       const ProxyConnectionState *state = container_of(node, ProxyConnectionState, node);
 
        return strcmp(name, state->userinfo->username);
 }
 
 static void state_free(struct AANode *node, void *arg)
 {
-       ProxyConnectionState *state = (ProxyConnectionState *)node;
+       ProxyConnectionState *state = container_of(node, ProxyConnectionState, node);
        if (state->db)
                PQfinish(state->db);
        memset(state, 0, sizeof(*state));
@@ -134,14 +134,14 @@ static void state_free(struct AANode *node, void *arg)
 static int userinfo_cmp(uintptr_t val, struct AANode *node)
 {
        const char *name = (const char *)val;
-       const ConnUserInfo *info = (ConnUserInfo *)node;
+       const ConnUserInfo *info = container_of(node, ConnUserInfo, node);
 
        return strcmp(name, info->username);
 }
 
 static void userinfo_free(struct AANode *node, void *arg)
 {
-       ConnUserInfo *info = (ConnUserInfo *)node;
+       ConnUserInfo *info = container_of(node, ConnUserInfo, node);
        pfree(info->username);
        if (info->extra_connstr)
        {
@@ -241,7 +241,7 @@ add_connection(ProxyCluster *cluster, const char *connstr, int part_num)
        /* check if already have it */
        node = aatree_search(&cluster->conn_tree, (uintptr_t)connstr);
        if (node)
-               conn = (ProxyConnection *)node;
+               conn = container_of(node, ProxyConnection, node);
 
        /* add new connection */
        if (!conn)
@@ -766,7 +766,7 @@ determine_compat_mode(ProxyCluster *cluster)
 
 static void inval_one_umap(struct AANode *n, void *arg)
 {
-       ConnUserInfo *info = (ConnUserInfo *)n;
+       ConnUserInfo *info = container_of(n, ConnUserInfo, node);
        SCInvalArg newStamp;
 
        if (info->needs_reload)
@@ -787,14 +787,14 @@ static void inval_one_umap(struct AANode *n, void *arg)
 
 static void inval_umapping(struct AANode *n, void *arg)
 {
-       ProxyCluster *cluster = (ProxyCluster *)n;
+       ProxyCluster *cluster = container_of(n, ProxyCluster, node);
 
        aatree_walk(&cluster->userinfo_tree, AA_WALK_IN_ORDER, inval_one_umap, arg);
 }
 
 static void inval_fserver(struct AANode *n, void *arg)
 {
-       ProxyCluster *cluster = (ProxyCluster *)n;
+       ProxyCluster *cluster = container_of(n, ProxyCluster, node);
        SCInvalArg newStamp = *(SCInvalArg *)arg;
 
        if (cluster->needs_reload)
@@ -897,7 +897,7 @@ new_cluster(const char *name)
 
 static void inval_userinfo_state(struct AANode *node, void *arg)
 {
-       ProxyConnectionState *cur = (ProxyConnectionState *)node;
+       ProxyConnectionState *cur = container_of(node, ProxyConnectionState, node);
        ConnUserInfo *userinfo = arg;
 
        if (cur->userinfo == userinfo && cur->db)
@@ -910,7 +910,7 @@ static void inval_userinfo_state(struct AANode *node, void *arg)
 
 static void inval_userinfo_conn(struct AANode *node, void *arg)
 {
-       ProxyConnection *conn = (ProxyConnection *)node;
+       ProxyConnection *conn = container_of(node, ProxyConnection, node);
        ConnUserInfo *userinfo = arg;
 
        aatree_walk(&conn->userstate_tree, AA_WALK_IN_ORDER, inval_userinfo_state, userinfo);
@@ -945,7 +945,7 @@ get_userinfo(ProxyCluster *cluster, Oid user_oid)
 
        node = aatree_search(&cluster->userinfo_tree, (uintptr_t)username);
        if (node) {
-               userinfo = (ConnUserInfo *)node;
+               userinfo = container_of(node, ConnUserInfo, node);
        } else {
                userinfo = MemoryContextAllocZero(cluster_mem, sizeof(*userinfo));
                userinfo->username = MemoryContextStrdup(cluster_mem, username);
@@ -1077,7 +1077,7 @@ fake_cluster(ProxyFunction *func, const char *connect_str)
        n = aatree_search(&fake_cluster_tree, (uintptr_t)connect_str);
        if (n)
        {
-               cluster = (ProxyCluster *)n;
+               cluster = container_of(n, ProxyCluster, node);
                goto done;
        }
 
@@ -1167,7 +1167,7 @@ plproxy_find_cluster(ProxyFunction *func, FunctionCallInfo fcinfo)
        /* search if cached */
        node = aatree_search(&cluster_tree, (uintptr_t)name);
        if (node)
-               cluster = (ProxyCluster *)node;
+               cluster = container_of(node, ProxyCluster, node);
 
        /* create if not */
        if (!cluster)
@@ -1203,7 +1203,7 @@ void plproxy_activate_connection(struct ProxyConnection *conn)
 
        node = aatree_search(&conn->userstate_tree, (uintptr_t)username);
        if (node) {
-               cur = (ProxyConnectionState *)node;
+               cur = container_of(node, ProxyConnectionState, node);
        } else {
                cur = MemoryContextAlloc(cluster_mem, sizeof(*cur));
                cur->userinfo = userinfo;
@@ -1223,7 +1223,7 @@ struct MaintInfo {
 
 static void clean_state(struct AANode *node, void *arg)
 {
-       ProxyConnectionState *cur = (ProxyConnectionState *)node;
+       ProxyConnectionState *cur = container_of(node, ProxyConnectionState, node);
        ConnUserInfo *uinfo = cur->userinfo;
        struct MaintInfo *maint = arg;
        ProxyConfig *cf = maint->cf;
@@ -1264,7 +1264,7 @@ static void clean_state(struct AANode *node, void *arg)
 
 static void clean_conn(struct AANode *node, void *arg)
 {
-       ProxyConnection *conn = (ProxyConnection *)node;
+       ProxyConnection *conn = container_of(node, ProxyConnection, node);
        struct MaintInfo *maint = arg;
 
        if (conn->res)
@@ -1278,7 +1278,7 @@ static void clean_conn(struct AANode *node, void *arg)
 
 static void clean_cluster(struct AANode *n, void *arg)
 {
-       ProxyCluster *cluster = (ProxyCluster *)n;
+       ProxyCluster *cluster = container_of(n, ProxyCluster, node);
        struct MaintInfo maint;
 
        maint.cf = &cluster->config;

diff --git a/src/plproxy.h b/src/plproxy.h
index 5f58321ee24e97b4d3e934b14a41157a83ea9a26..b49cae1cb34a6f1fa4ec23914a99dd6c3efe2c57 100644 (file)
--- a/src/plproxy.h
+++ b/src/plproxy.h
@@ -64,6 +64,16 @@
 #error PL/Proxy requires 8.2+
 #endif
 
+/* give offset of a field inside struct */
+#ifndef offsetof
+#define offsetof(type, field) ((unsigned long)&(((type *)0)->field))
+#endif
+
+/* given pointer to field inside struct, return pointer to struct */
+#ifndef container_of
+#define container_of(ptr, type, field) ((type *)((char *)(ptr) - offsetof(type, field)))
+#endif
+
 /*
  * backwards compat with 8.2
  */