refactor: split resolve_server() into functions

This commit splits the branch-heavy resolve_server() function into
various sub-functions, in order to reduce the amount of nested
if/else-statements.

Beside this, it also removes many else-sequences, by returning in the
previous if-statement.

Closes #9283

diff --git a/lib/url.c b/lib/url.c
index a57c8da9faa40851eea1d5515fb3820e5790085d..14a92007874fdec66f25a2d80418d622958af51f 100644 (file)
--- a/lib/url.c
+++ b/lib/url.c
@@ -3414,142 +3414,166 @@ static CURLcode parse_connect_to_slist(struct Curl_easy *data,
   return result;
 }
 
-/*************************************************************
- * Resolve the address of the server or proxy
- *************************************************************/
-static CURLcode resolve_server(struct Curl_easy *data,
-                               struct connectdata *conn,
-                               bool *async)
+#ifdef USE_UNIX_SOCKETS
+static CURLcode resolve_unix(struct Curl_easy *data,
+                             struct connectdata *conn,
+                             char *unix_path)
 {
-  CURLcode result = CURLE_OK;
-  timediff_t timeout_ms = Curl_timeleft(data, NULL, TRUE);
+  struct Curl_dns_entry *hostaddr = NULL;
+  bool longpath = FALSE;
 
-  DEBUGASSERT(conn);
-  DEBUGASSERT(data);
-  /*************************************************************
-   * Resolve the name of the server or proxy
-   *************************************************************/
-  if(conn->bits.reuse)
-    /* We're reusing the connection - no need to resolve anything, and
-       idnconvert_hostname() was called already in create_conn() for the re-use
-       case. */
-    *async = FALSE;
+  DEBUGASSERT(unix_path);
+  DEBUGASSERT(conn->dns_entry == NULL);
 
-  else {
-    /* this is a fresh connect */
-    int rc;
-    struct Curl_dns_entry *hostaddr = NULL;
+  /* Unix domain sockets are local. The host gets ignored, just use the
+   * specified domain socket address. Do not cache "DNS entries". There is
+   * no DNS involved and we already have the filesystem path available. */
+  hostaddr = calloc(1, sizeof(struct Curl_dns_entry));
+  if(!hostaddr)
+    return CURLE_OUT_OF_MEMORY;
 
-#ifdef USE_UNIX_SOCKETS
-    char *unix_path = NULL;
+  hostaddr->addr = Curl_unix2addr(unix_path, &longpath,
+                                  conn->bits.abstract_unix_socket);
+  if(!hostaddr->addr) {
+    if(longpath)
+      /* Long paths are not supported for now */
+      failf(data, "Unix socket path too long: '%s'", unix_path);
+    free(hostaddr);
+    return longpath ? CURLE_COULDNT_RESOLVE_HOST : CURLE_OUT_OF_MEMORY;
+  }
 
-    if(conn->unix_domain_socket)
-      unix_path = conn->unix_domain_socket;
-#ifndef CURL_DISABLE_PROXY
-    else if(conn->socks_proxy.host.name
-        && !strncmp(UNIX_SOCKET_PREFIX"/",
-          conn->socks_proxy.host.name, sizeof(UNIX_SOCKET_PREFIX)))
-      unix_path = conn->socks_proxy.host.name + sizeof(UNIX_SOCKET_PREFIX) - 1;
+  hostaddr->inuse++;
+  conn->dns_entry = hostaddr;
+  return CURLE_OK;
+}
 #endif
 
-    if(unix_path) {
-      /* Unix domain sockets are local. The host gets ignored, just use the
-       * specified domain socket address. Do not cache "DNS entries". There is
-       * no DNS involved and we already have the filesystem path available */
+#ifndef CURL_DISABLE_PROXY
+static CURLcode resolve_proxy(struct Curl_easy *data,
+                              struct connectdata *conn,
+                              bool *async)
+{
+  struct Curl_dns_entry *hostaddr = NULL;
+  struct hostname *host;
+  timediff_t timeout_ms = Curl_timeleft(data, NULL, TRUE);
+  int rc;
 
-      hostaddr = calloc(1, sizeof(struct Curl_dns_entry));
-      if(!hostaddr)
-        result = CURLE_OUT_OF_MEMORY;
-      else {
-        bool longpath = FALSE;
-        hostaddr->addr = Curl_unix2addr(unix_path, &longpath,
-                                        conn->bits.abstract_unix_socket);
-        if(hostaddr->addr)
-          hostaddr->inuse++;
-        else {
-          /* Long paths are not supported for now */
-          if(longpath) {
-            failf(data, "Unix socket path too long: '%s'", unix_path);
-            result = CURLE_COULDNT_RESOLVE_HOST;
-          }
-          else
-            result = CURLE_OUT_OF_MEMORY;
-          free(hostaddr);
-          hostaddr = NULL;
-        }
-        conn->transport = TRNSPRT_UNIX;
-      }
-    }
-    else
+  DEBUGASSERT(conn->dns_entry == NULL);
+
+  host = conn->bits.socksproxy ? &conn->socks_proxy.host :
+    &conn->http_proxy.host;
+
+  conn->hostname_resolve = strdup(host->name);
+  if(!conn->hostname_resolve)
+    return CURLE_OUT_OF_MEMORY;
+
+  rc = Curl_resolv_timeout(data, conn->hostname_resolve, (int)conn->port,
+                           &hostaddr, timeout_ms);
+  conn->dns_entry = hostaddr;
+  if(rc == CURLRESOLV_PENDING)
+    *async = TRUE;
+  else if(rc == CURLRESOLV_TIMEDOUT)
+    return CURLE_OPERATION_TIMEDOUT;
+  else if(!hostaddr) {
+    failf(data, "Couldn't resolve proxy '%s'", host->dispname);
+    return CURLE_COULDNT_RESOLVE_PROXY;
+  }
+
+  return CURLE_OK;
+}
 #endif
 
-    if(!CONN_IS_PROXIED(conn)) {
-      struct hostname *connhost;
-      if(conn->bits.conn_to_host)
-        connhost = &conn->conn_to_host;
-      else
-        connhost = &conn->host;
+static CURLcode resolve_ip(struct Curl_easy *data,
+                           struct connectdata *conn,
+                           bool *async)
+{
+  struct Curl_dns_entry *hostaddr = NULL;
+  struct hostname *connhost;
+  timediff_t timeout_ms = Curl_timeleft(data, NULL, TRUE);
+  int rc;
 
-      /* If not connecting via a proxy, extract the port from the URL, if it is
-       * there, thus overriding any defaults that might have been set above. */
-      if(conn->bits.conn_to_port)
-        conn->port = conn->conn_to_port;
-      else
-        conn->port = conn->remote_port;
+  DEBUGASSERT(conn->dns_entry == NULL);
 
-      /* Resolve target host right on */
-      conn->hostname_resolve = strdup(connhost->name);
-      if(!conn->hostname_resolve)
-        return CURLE_OUT_OF_MEMORY;
-      rc = Curl_resolv_timeout(data, conn->hostname_resolve, (int)conn->port,
-                               &hostaddr, timeout_ms);
-      if(rc == CURLRESOLV_PENDING)
-        *async = TRUE;
-
-      else if(rc == CURLRESOLV_TIMEDOUT) {
-        failf(data, "Failed to resolve host '%s' with timeout after %ld ms",
-              connhost->dispname,
-              Curl_timediff(Curl_now(), data->progress.t_startsingle));
-        result = CURLE_OPERATION_TIMEDOUT;
-      }
-      else if(!hostaddr) {
-        failf(data, "Could not resolve host: %s", connhost->dispname);
-        result = CURLE_COULDNT_RESOLVE_HOST;
-        /* don't return yet, we need to clean up the timeout first */
-      }
-    }
-#ifndef CURL_DISABLE_PROXY
-    else {
-      /* This is a proxy that hasn't been resolved yet. */
+  connhost = conn->bits.conn_to_host ? &conn->conn_to_host : &conn->host;
 
-      struct hostname * const host = conn->bits.socksproxy ?
-        &conn->socks_proxy.host : &conn->http_proxy.host;
+  /* If not connecting via a proxy, extract the port from the URL, if it is
+   * there, thus overriding any defaults that might have been set above. */
+  conn->port = conn->bits.conn_to_port ? conn->conn_to_port :
+    conn->remote_port;
 
-      /* resolve proxy */
-      conn->hostname_resolve = strdup(host->name);
-      if(!conn->hostname_resolve)
-        return CURLE_OUT_OF_MEMORY;
-      rc = Curl_resolv_timeout(data, conn->hostname_resolve, (int)conn->port,
-                               &hostaddr, timeout_ms);
+  /* Resolve target host right on */
+  conn->hostname_resolve = strdup(connhost->name);
+  if(!conn->hostname_resolve)
+    return CURLE_OUT_OF_MEMORY;
 
-      if(rc == CURLRESOLV_PENDING)
-        *async = TRUE;
+  rc = Curl_resolv_timeout(data, conn->hostname_resolve, (int)conn->port,
+                           &hostaddr, timeout_ms);
+  conn->dns_entry = hostaddr;
+  if(rc == CURLRESOLV_PENDING)
+    *async = TRUE;
+  else if(rc == CURLRESOLV_TIMEDOUT) {
+    failf(data, "Failed to resolve host '%s' with timeout after %ld ms",
+          connhost->dispname,
+          Curl_timediff(Curl_now(), data->progress.t_startsingle));
+    return CURLE_OPERATION_TIMEDOUT;
+  }
+  else if(!hostaddr) {
+    failf(data, "Could not resolve host: %s", connhost->dispname);
+    return CURLE_COULDNT_RESOLVE_HOST;
+  }
 
-      else if(rc == CURLRESOLV_TIMEDOUT)
-        result = CURLE_OPERATION_TIMEDOUT;
+  return CURLE_OK;
+}
 
-      else if(!hostaddr) {
-        failf(data, "Couldn't resolve proxy '%s'", host->dispname);
-        result = CURLE_COULDNT_RESOLVE_PROXY;
-        /* don't return yet, we need to clean up the timeout first */
-      }
-    }
+/* Perform a fresh resolve */
+static CURLcode resolve_fresh(struct Curl_easy *data,
+                              struct connectdata *conn,
+                              bool *async)
+{
+#ifdef USE_UNIX_SOCKETS
+  char *unix_path = conn->unix_domain_socket;
+
+#ifndef CURL_DISABLE_PROXY
+  if(!unix_path && conn->socks_proxy.host.name &&
+     !strncmp(UNIX_SOCKET_PREFIX"/",
+              conn->socks_proxy.host.name, sizeof(UNIX_SOCKET_PREFIX)))
+    unix_path = conn->socks_proxy.host.name + sizeof(UNIX_SOCKET_PREFIX) - 1;
 #endif
-    DEBUGASSERT(conn->dns_entry == NULL);
-    conn->dns_entry = hostaddr;
+
+  if(unix_path) {
+    conn->transport = TRNSPRT_UNIX;
+    return resolve_unix(data, conn, unix_path);
   }
+#endif
 
-  return result;
+#ifndef CURL_DISABLE_PROXY
+  if(CONN_IS_PROXIED(conn))
+    return resolve_proxy(data, conn, async);
+#endif
+
+  return resolve_ip(data, conn, async);
+}
+
+/*************************************************************
+ * Resolve the address of the server or proxy
+ *************************************************************/
+static CURLcode resolve_server(struct Curl_easy *data,
+                               struct connectdata *conn,
+                               bool *async)
+{
+  DEBUGASSERT(conn);
+  DEBUGASSERT(data);
+
+  /* Resolve the name of the server or proxy */
+  if(conn->bits.reuse) {
+    /* We're reusing the connection - no need to resolve anything, and
+       idnconvert_hostname() was called already in create_conn() for the re-use
+       case. */
+    *async = FALSE;
+    return CURLE_OK;
+  }
+
+  return resolve_fresh(data, conn, async);
 }
 
 /*