unix, win: store ares handles in a binary tree

Store the uv_ares_task_t handles in a red-black tree, not a linked list.

Fixes #72.

include/uv.h

@@ -1482,8 +1482,8 @@ struct uv_counters_s {
 
 struct uv_loop_s {
   UV_LOOP_PRIVATE_FIELDS
-  /* list used for ares task handles */
-  uv_ares_task_t* uv_ares_handles_;
+  /* RB_HEAD(uv__ares_tasks, uv_ares_task_t) */
+  struct uv__ares_tasks { uv_ares_task_t* rbh_root; } uv_ares_handles_;
   /* Various thing for libeio. */
   uv_async_t uv_eio_want_poll_notifier;
   uv_async_t uv_eio_done_poll_notifier;

src/unix/cares.c

@@ -62,7 +62,7 @@ static void uv__ares_io(struct ev_loop* ev, struct ev_io* watcher,
 
 
 /* Allocates and returns a new uv_ares_task_t */
-static uv_ares_task_t* uv__ares_task_create(int fd) {
+static uv_ares_task_t* uv__ares_task_create(uv_loop_t* loop, int fd) {
   uv_ares_task_t* h = malloc(sizeof(uv_ares_task_t));
 
   if (h == NULL) {
@@ -70,6 +70,7 @@ static uv_ares_task_t* uv__ares_task_create(int fd) {
     return NULL;
   }
 
+  h->loop = loop;
   h->sock = fd;
 
   ev_io_init(&h->read_watcher, uv__ares_io, fd, EV_READ);
@@ -102,7 +103,7 @@ static void uv__ares_sockstate_cb(void* data, ares_socket_t sock,
         ev_timer_again(loop->ev, &loop->timer);
       }
 
-      h = uv__ares_task_create(sock);
+      h = uv__ares_task_create(loop, sock);
       uv_add_ares_handle(loop, h);
     }
 

src/unix/core.c

@@ -145,6 +145,7 @@ void uv_close(uv_handle_t* handle, uv_close_cb close_cb) {
 static int uv__loop_init(uv_loop_t* loop,
                          struct ev_loop *(ev_loop_new)(unsigned int flags)) {
   memset(loop, 0, sizeof(*loop));
+  RB_INIT(&loop->uv_ares_handles_);
 #if HAVE_KQUEUE
   loop->ev = ev_loop_new(EVBACKEND_KQUEUE);
 #else

src/uv-common.c

@@ -32,6 +32,10 @@
 #include "ares/inet_net_pton.h"
 #include "ares/inet_ntop.h"
 
+#if !defined(__GNUC__) && !defined(__clang__)
+# define __attribute__(x)
+#endif
+
 
 size_t uv_strlcpy(char* dst, const char* src, size_t size) {
   size_t n;
@@ -180,57 +184,44 @@ int uv_ip6_name(struct sockaddr_in6* src, char* dst, size_t size) {
 }
 
 
-/* find matching ares handle in list */
+static int cmp_ares_tasks(const uv_ares_task_t* a, const uv_ares_task_t* b) {
+  if (a->sock < b->sock) return -1;
+  if (a->sock > b->sock) return 1;
+  return 0;
+}
+
+
+RB_GENERATE_INTERNAL(uv__ares_tasks, uv_ares_task_s, node, cmp_ares_tasks,
+  inline static __attribute__((unused)))
+
+
+/* add ares handle to list */
 void uv_add_ares_handle(uv_loop_t* loop, uv_ares_task_t* handle) {
-  handle->loop = loop;
-  handle->ares_next = loop->uv_ares_handles_;
-  handle->ares_prev = NULL;
-
-  if (loop->uv_ares_handles_) {
-    loop->uv_ares_handles_->ares_prev = handle;
-  }
-
-  loop->uv_ares_handles_ = handle;
+  assert(loop == handle->loop);
+  RB_INSERT(uv__ares_tasks, &loop->uv_ares_handles_, handle);
 }
 
+
 /* find matching ares handle in list */
-/* TODO: faster lookup */
 uv_ares_task_t* uv_find_ares_handle(uv_loop_t* loop, ares_socket_t sock) {
-  uv_ares_task_t* handle = loop->uv_ares_handles_;
-
-  while (handle != NULL) {
-    if (handle->sock == sock) {
-      break;
-    }
-    handle = handle->ares_next;
-  }
-
-  return handle;
+  uv_ares_task_t handle;
+  handle.sock = sock;
+  return RB_FIND(uv__ares_tasks, &loop->uv_ares_handles_, &handle);
 }
 
+
 /* remove ares handle in list */
 void uv_remove_ares_handle(uv_ares_task_t* handle) {
-  uv_loop_t* loop = handle->loop;
-
-  if (handle == loop->uv_ares_handles_) {
-    loop->uv_ares_handles_ = handle->ares_next;
-  }
-
-  if (handle->ares_next) {
-    handle->ares_next->ares_prev = handle->ares_prev;
-  }
-
-  if (handle->ares_prev) {
-    handle->ares_prev->ares_next = handle->ares_next;
-  }
+  RB_REMOVE(uv__ares_tasks, &handle->loop->uv_ares_handles_, handle);
 }
 
 
 /* Returns 1 if the uv_ares_handles_ list is empty. 0 otherwise. */
 int uv_ares_handles_empty(uv_loop_t* loop) {
-  return loop->uv_ares_handles_ ? 0 : 1;
+  return RB_EMPTY(&loop->uv_ares_handles_);
 }
 
+
 int uv_tcp_bind(uv_tcp_t* handle, struct sockaddr_in addr) {
   if (handle->type != UV_TCP || addr.sin_family != AF_INET) {
     uv__set_artificial_error(handle->loop, UV_EFAULT);
@@ -240,6 +231,7 @@ int uv_tcp_bind(uv_tcp_t* handle, struct sockaddr_in addr) {
   return uv__tcp_bind(handle, addr);
 }
 
+
 int uv_tcp_bind6(uv_tcp_t* handle, struct sockaddr_in6 addr) {
   if (handle->type != UV_TCP || addr.sin6_family != AF_INET6) {
     uv__set_artificial_error(handle->loop, UV_EFAULT);
@@ -249,6 +241,7 @@ int uv_tcp_bind6(uv_tcp_t* handle, struct sockaddr_in6 addr) {
   return uv__tcp_bind6(handle, addr);
 }
 
+
 int uv_udp_bind(uv_udp_t* handle, struct sockaddr_in addr,
     unsigned int flags) {
   if (handle->type != UV_UDP || addr.sin_family != AF_INET) {
@@ -259,6 +252,7 @@ int uv_udp_bind(uv_udp_t* handle, struct sockaddr_in addr,
   return uv__udp_bind(handle, addr, flags);
 }
 
+
 int uv_udp_bind6(uv_udp_t* handle, struct sockaddr_in6 addr,
     unsigned int flags) {
   if (handle->type != UV_UDP || addr.sin6_family != AF_INET6) {
@@ -269,6 +263,7 @@ int uv_udp_bind6(uv_udp_t* handle, struct sockaddr_in6 addr,
   return uv__udp_bind6(handle, addr, flags);
 }
 
+
 int uv_tcp_connect(uv_connect_t* req,
                    uv_tcp_t* handle,
                    struct sockaddr_in address,
@@ -281,6 +276,7 @@ int uv_tcp_connect(uv_connect_t* req,
   return uv__tcp_connect(req, handle, address, cb);
 }
 
+
 int uv_tcp_connect6(uv_connect_t* req,
                     uv_tcp_t* handle,
                     struct sockaddr_in6 address,

src/uv-common.h

@@ -28,6 +28,7 @@
 #define UV_COMMON_H_
 
 #include "uv.h"
+#include "tree.h"
 
 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
 
@@ -35,8 +36,7 @@
 struct uv_ares_task_s {
   UV_HANDLE_FIELDS
   UV_ARES_TASK_PRIVATE_FIELDS
-  uv_ares_task_t* ares_prev;
-  uv_ares_task_t* ares_next;
+  RB_ENTRY(uv_ares_task_s) node;
 };
 
 

src/win/cares.c

@@ -159,6 +159,7 @@ static void uv_ares_sockstate_cb(void *data, ares_socket_t sock, int read,
       }
       uv_handle_ares->type = UV_ARES_TASK;
       uv_handle_ares->close_cb = NULL;
+      uv_handle_ares->loop = loop;
       uv_handle_ares->data = loop;
       uv_handle_ares->sock = sock;
       uv_handle_ares->h_wait = NULL;

src/win/core.c

@@ -59,7 +59,6 @@ static void uv_init(void) {
 
 
 static void uv_loop_init(uv_loop_t* loop) {
-  loop->uv_ares_handles_ = NULL;
   /* Create an I/O completion port */
   loop->iocp = CreateIoCompletionPort(INVALID_HANDLE_VALUE, NULL, 0, 1);
   if (loop->iocp == NULL) {
@@ -75,6 +74,7 @@ static void uv_loop_init(uv_loop_t* loop) {
   loop->endgame_handles = NULL;
 
   RB_INIT(&loop->timers);
+  RB_INIT(&loop->uv_ares_handles_);
 
   loop->check_handles = NULL;
   loop->prepare_handles = NULL;