multi: add curl_multi_wait()

/*
 * Name:     curl_multi_wait()
 *
 * Desc:     Poll on all fds within a CURLM set as well as any
 *           additional fds passed to the function.
 *
 * Returns:  CURLMcode type, general multi error code.
 */
CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
                                      struct curl_waitfd extra_fds[],
                                      unsigned int extra_nfds,
                                      int timeout_ms);

include/curl/multi.h

@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2012, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -89,6 +89,19 @@ struct CURLMsg {
 };
 typedef struct CURLMsg CURLMsg;
 
+/* Based on poll(2) structure and values.
+ * We don't use pollfd and POLL* constants explicitly
+ * to cover platforms without poll(). */
+#define CURL_WAIT_POLLIN    0x0001
+#define CURL_WAIT_POLLPRI   0x0002
+#define CURL_WAIT_POLLOUT   0x0004
+
+struct curl_waitfd {
+  curl_socket_t fd;
+  short events;
+  short revents; /* not supported yet */
+};
+
 /*
  * Name:    curl_multi_init()
  *
@@ -133,6 +146,19 @@ CURL_EXTERN CURLMcode curl_multi_fdset(CURLM *multi_handle,
                                        fd_set *exc_fd_set,
                                        int *max_fd);
 
+/*
+ * Name:     curl_multi_wait()
+ *
+ * Desc:     Poll on all fds within a CURLM set as well as any
+ *           additional fds passed to the function.
+ *
+ * Returns:  CURLMcode type, general multi error code.
+ */
+CURL_EXTERN CURLMcode curl_multi_wait(CURLM *multi_handle,
+                                      struct curl_waitfd extra_fds[],
+                                      unsigned int extra_nfds,
+                                      int timeout_ms);
+
  /*
   * Name:    curl_multi_perform()
   *

lib/multi.c

@@ -941,6 +941,93 @@ CURLMcode curl_multi_fdset(CURLM *multi_handle,
   return CURLM_OK;
 }
 
+CURLMcode curl_multi_wait(CURLM *multi_handle,
+                          struct curl_waitfd extra_fds[],
+                          unsigned int extra_nfds,
+                          int timeout_ms)
+{
+  struct Curl_multi *multi=(struct Curl_multi *)multi_handle;
+  struct Curl_one_easy *easy;
+  curl_socket_t sockbunch[MAX_SOCKSPEREASYHANDLE];
+  int bitmap;
+  unsigned int i;
+  unsigned int nfds = extra_nfds;
+  struct pollfd *ufds;
+
+  if(!GOOD_MULTI_HANDLE(multi))
+    return CURLM_BAD_HANDLE;
+
+  /* Count up how many fds we have from the multi handle */
+  easy=multi->easy.next;
+  while(easy != &multi->easy) {
+    bitmap = multi_getsock(easy, sockbunch, MAX_SOCKSPEREASYHANDLE);
+
+    for(i=0; i< MAX_SOCKSPEREASYHANDLE; i++) {
+      curl_socket_t s = CURL_SOCKET_BAD;
+
+      if(bitmap & GETSOCK_READSOCK(i)) {
+        ++nfds;
+        s = sockbunch[i];
+      }
+      if(bitmap & GETSOCK_WRITESOCK(i)) {
+        ++nfds;
+        s = sockbunch[i];
+      }
+      if(s == CURL_SOCKET_BAD) {
+        break;
+      }
+    }
+
+    easy = easy->next; /* check next handle */
+  }
+
+  ufds = (struct pollfd *)malloc(nfds * sizeof(struct pollfd));
+  nfds = 0;
+
+  /* Add the curl handles to our pollfds first */
+  easy=multi->easy.next;
+  while(easy != &multi->easy) {
+    bitmap = multi_getsock(easy, sockbunch, MAX_SOCKSPEREASYHANDLE);
+
+    for(i=0; i< MAX_SOCKSPEREASYHANDLE; i++) {
+      curl_socket_t s = CURL_SOCKET_BAD;
+
+      if(bitmap & GETSOCK_READSOCK(i)) {
+        ufds[nfds].fd = sockbunch[i];
+        ufds[nfds].events = POLLIN;
+        ++nfds;
+        s = sockbunch[i];
+      }
+      if(bitmap & GETSOCK_WRITESOCK(i)) {
+        ufds[nfds].fd = sockbunch[i];
+        ufds[nfds].events = POLLOUT;
+        ++nfds;
+        s = sockbunch[i];
+      }
+      if(s == CURL_SOCKET_BAD) {
+        break;
+      }
+    }
+
+    easy = easy->next; /* check next handle */
+  }
+
+  /* Add external file descriptions from poll-like struct curl_waitfd */
+  for(i = 0; i < extra_nfds; i++) {
+    ufds[nfds].fd = extra_fds[i].fd;
+    ufds[nfds].events = (short) (
+      ((extra_fds[i].events & CURL_WAIT_POLLIN)  ? POLLIN  : 0) |
+      ((extra_fds[i].events & CURL_WAIT_POLLPRI) ? POLLPRI : 0) |
+      ((extra_fds[i].events & CURL_WAIT_POLLOUT) ? POLLOUT : 0) );
+    ++nfds;
+  }
+
+  /* wait... */
+  Curl_poll(ufds, nfds, timeout_ms);
+  free(ufds);
+  return CURLM_OK;
+}
+
 static CURLMcode multi_runsingle(struct Curl_multi *multi,
                                  struct timeval now,
                                  struct Curl_one_easy *easy)