dns: don't rely on libuv for c-ares integration

diff --git a/node.gyp b/node.gyp
index 84ec69d..cef573b 100644 (file)
--- a/node.gyp
+++ b/node.gyp
@@ -57,6 +57,7 @@
       'type': 'executable',
 
       'dependencies': [
+        'deps/cares/cares.gyp:cares',
         'deps/http_parser/http_parser.gyp:http_parser',
         'deps/uv/uv.gyp:uv',
         'node_js2c#host',
@@ -117,6 +118,7 @@
         'src/req_wrap.h',
         'src/slab_allocator.h',
         'src/stream_wrap.h',
+        'src/tree.h',
         'src/v8_typed_array.h',
         'deps/http_parser/http_parser.h',
         '<(SHARED_INTERMEDIATE_DIR)/node_natives.h',

diff --git a/src/cares_wrap.cc b/src/cares_wrap.cc
index 30d7238..3d1cb23 100644 (file)
--- a/src/cares_wrap.cc
+++ b/src/cares_wrap.cc
@@ -20,12 +20,17 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <assert.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define CARES_STATICLIB
+#include "ares.h"
 #include "node.h"
 #include "req_wrap.h"
+#include "tree.h"
 #include "uv.h"
 
-#include <string.h>
-
 #if defined(__OpenBSD__) || defined(__MINGW32__) || defined(_MSC_VER)
 # include <nameser.h>
 #else
@@ -69,9 +74,139 @@ using v8::Value;
 
 typedef class ReqWrap<uv_getaddrinfo_t> GetAddrInfoReqWrap;
 
-static Persistent<String> oncomplete_sym;
+struct ares_task_t {
+  UV_HANDLE_FIELDS
+  ares_socket_t sock;
+  uv_poll_t poll_watcher;
+  RB_ENTRY(ares_task_t) node;
+};
 
+
+static Persistent<String> oncomplete_sym;
 static ares_channel ares_channel;
+static uv_timer_t ares_timer;
+static RB_HEAD(ares_task_list, ares_task_t) ares_tasks;
+
+
+static int cmp_ares_tasks(const ares_task_t* a, const ares_task_t* b) {
+  if (a->sock < b->sock) return -1;
+  if (a->sock > b->sock) return 1;
+  return 0;
+}
+
+
+RB_GENERATE_STATIC(ares_task_list, ares_task_t, node, cmp_ares_tasks)
+
+
+
+/* This is called once per second by loop->timer. It is used to constantly */
+/* call back into c-ares for possibly processing timeouts. */
+static void ares_timeout(uv_timer_t* handle, int status) {
+  assert(!RB_EMPTY(&ares_tasks));
+  ares_process_fd(ares_channel, ARES_SOCKET_BAD, ARES_SOCKET_BAD);
+}
+
+
+static void ares_poll_cb(uv_poll_t* watcher, int status, int events) {
+  ares_task_t* task = container_of(watcher, ares_task_t, poll_watcher);
+
+  /* Reset the idle timer */
+  uv_timer_again(&ares_timer);
+
+  if (status < 0) {
+    /* An error happened. Just pretend that the socket is both readable and */
+    /* writable. */
+    ares_process_fd(ares_channel, task->sock, task->sock);
+    return;
+  }
+
+  /* Process DNS responses */
+  ares_process_fd(ares_channel,
+                  events & UV_READABLE ? task->sock : ARES_SOCKET_BAD,
+                  events & UV_WRITABLE ? task->sock : ARES_SOCKET_BAD);
+}
+
+
+static void ares_poll_close_cb(uv_handle_t* watcher) {
+  ares_task_t* task = container_of(watcher, ares_task_t, poll_watcher);
+  free(task);
+}
+
+
+/* Allocates and returns a new ares_task_t */
+static ares_task_t* ares_task_create(uv_loop_t* loop, ares_socket_t sock) {
+  ares_task_t* task = (ares_task_t*) malloc(sizeof *task);
+
+  if (task == NULL) {
+    /* Out of memory. */
+    return NULL;
+  }
+
+  task->loop = loop;
+  task->sock = sock;
+
+  if (uv_poll_init_socket(loop, &task->poll_watcher, sock) < 0) {
+    /* This should never happen. */
+    free(task);
+    return NULL;
+  }
+
+  return task;
+}
+
+
+/* Callback from ares when socket operation is started */
+static void ares_sockstate_cb(void* data, ares_socket_t sock,
+    int read, int write) {
+  uv_loop_t* loop = (uv_loop_t*) data;
+  ares_task_t* task;
+
+  ares_task_t lookup_task;
+  lookup_task.sock = sock;
+  task = RB_FIND(ares_task_list, &ares_tasks, &lookup_task);
+
+  if (read || write) {
+    if (!task) {
+      /* New socket */
+
+      /* If this is the first socket then start the timer. */
+      if (!uv_is_active((uv_handle_t*) &ares_timer)) {
+        assert(RB_EMPTY(&ares_tasks));
+        uv_timer_start(&ares_timer, ares_timeout, 1000, 1000);
+      }
+
+      task = ares_task_create(loop, sock);
+      if (task == NULL) {
+        /* This should never happen unless we're out of memory or something */
+        /* is seriously wrong. The socket won't be polled, but the the query */
+        /* will eventually time out. */
+        return;
+      }
+
+      RB_INSERT(ares_task_list, &ares_tasks, task);
+    }
+
+    /* This should never fail. If it fails anyway, the query will eventually */
+    /* time out. */
+    uv_poll_start(&task->poll_watcher,
+                  (read ? UV_READABLE : 0) | (write ? UV_WRITABLE : 0),
+                  ares_poll_cb);
+
+  } else {
+    /* read == 0 and write == 0 this is c-ares's way of notifying us that */
+    /* the socket is now closed. We must free the data associated with */
+    /* socket. */
+    assert(task &&
+           "When an ares socket is closed we should have a handle for it");
+
+    RB_REMOVE(ares_task_list, &ares_tasks, task);
+    uv_close((uv_handle_t*) &task->poll_watcher, ares_poll_close_cb);
+
+    if (RB_EMPTY(&ares_tasks)) {
+      uv_timer_stop(&ares_timer);
+    }
+  }
+}
 
 
 static Local<Array> HostentToAddresses(struct hostent* host) {
@@ -736,8 +871,16 @@ static void Initialize(Handle<Object> target) {
   assert(r == ARES_SUCCESS);
 
   struct ares_options options;
-  uv_ares_init_options(uv_default_loop(), &ares_channel, &options, 0);
-  assert(r == 0);
+  options.sock_state_cb = ares_sockstate_cb;
+  options.sock_state_cb_data = uv_default_loop();
+
+  /* We do the call to ares_init_option for caller. */
+  r = ares_init_options(&ares_channel, &options, ARES_OPT_SOCK_STATE_CB);
+  assert(r == ARES_SUCCESS);
+
+  /* Initialize the timeout timer. The timer won't be started until the */
+  /* first socket is opened. */
+  uv_timer_init(uv_default_loop(), &ares_timer);
 
   NODE_SET_METHOD(target, "queryA", Query<QueryAWrap>);
   NODE_SET_METHOD(target, "queryAaaa", Query<QueryAaaaWrap>);

diff --git a/src/tree.h b/src/tree.h
new file mode 100644 (file)
index 0000000..f936416
--- /dev/null
+++ b/src/tree.h
@@ -0,0 +1,768 @@
+/*-
+ * Copyright 2002 Niels Provos <provos@citi.umich.edu>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef  UV_TREE_H_
+#define  UV_TREE_H_
+
+#ifndef UV__UNUSED
+# if __GNUC__
+#  define UV__UNUSED __attribute__((unused))
+# else
+#  define UV__UNUSED
+# endif
+#endif
+
+/*
+ * This file defines data structures for different types of trees:
+ * splay trees and red-black trees.
+ *
+ * A splay tree is a self-organizing data structure.  Every operation
+ * on the tree causes a splay to happen.  The splay moves the requested
+ * node to the root of the tree and partly rebalances it.
+ *
+ * This has the benefit that request locality causes faster lookups as
+ * the requested nodes move to the top of the tree.  On the other hand,
+ * every lookup causes memory writes.
+ *
+ * The Balance Theorem bounds the total access time for m operations
+ * and n inserts on an initially empty tree as O((m + n)lg n).  The
+ * amortized cost for a sequence of m accesses to a splay tree is O(lg n);
+ *
+ * A red-black tree is a binary search tree with the node color as an
+ * extra attribute.  It fulfills a set of conditions:
+ *  - every search path from the root to a leaf consists of the
+ *    same number of black nodes,
+ *  - each red node (except for the root) has a black parent,
+ *  - each leaf node is black.
+ *
+ * Every operation on a red-black tree is bounded as O(lg n).
+ * The maximum height of a red-black tree is 2lg (n+1).
+ */
+
+#define SPLAY_HEAD(name, type)                                                \
+struct name {                                                                 \
+  struct type *sph_root; /* root of the tree */                               \
+}
+
+#define SPLAY_INITIALIZER(root)                                               \
+  { NULL }
+
+#define SPLAY_INIT(root) do {                                                 \
+  (root)->sph_root = NULL;                                                    \
+} while (/*CONSTCOND*/ 0)
+
+#define SPLAY_ENTRY(type)                                                     \
+struct {                                                                      \
+  struct type *spe_left;          /* left element */                          \
+  struct type *spe_right;         /* right element */                         \
+}
+
+#define SPLAY_LEFT(elm, field)    (elm)->field.spe_left
+#define SPLAY_RIGHT(elm, field)   (elm)->field.spe_right
+#define SPLAY_ROOT(head)          (head)->sph_root
+#define SPLAY_EMPTY(head)         (SPLAY_ROOT(head) == NULL)
+
+/* SPLAY_ROTATE_{LEFT,RIGHT} expect that tmp hold SPLAY_{RIGHT,LEFT} */
+#define SPLAY_ROTATE_RIGHT(head, tmp, field) do {                             \
+  SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(tmp, field);              \
+  SPLAY_RIGHT(tmp, field) = (head)->sph_root;                                 \
+  (head)->sph_root = tmp;                                                     \
+} while (/*CONSTCOND*/ 0)
+
+#define SPLAY_ROTATE_LEFT(head, tmp, field) do {                              \
+  SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(tmp, field);              \
+  SPLAY_LEFT(tmp, field) = (head)->sph_root;                                  \
+  (head)->sph_root = tmp;                                                     \
+} while (/*CONSTCOND*/ 0)
+
+#define SPLAY_LINKLEFT(head, tmp, field) do {                                 \
+  SPLAY_LEFT(tmp, field) = (head)->sph_root;                                  \
+  tmp = (head)->sph_root;                                                     \
+  (head)->sph_root = SPLAY_LEFT((head)->sph_root, field);                     \
+} while (/*CONSTCOND*/ 0)
+
+#define SPLAY_LINKRIGHT(head, tmp, field) do {                                \
+  SPLAY_RIGHT(tmp, field) = (head)->sph_root;                                 \
+  tmp = (head)->sph_root;                                                     \
+  (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field);                    \
+} while (/*CONSTCOND*/ 0)
+
+#define SPLAY_ASSEMBLE(head, node, left, right, field) do {                   \
+  SPLAY_RIGHT(left, field) = SPLAY_LEFT((head)->sph_root, field);             \
+  SPLAY_LEFT(right, field) = SPLAY_RIGHT((head)->sph_root, field);            \
+  SPLAY_LEFT((head)->sph_root, field) = SPLAY_RIGHT(node, field);             \
+  SPLAY_RIGHT((head)->sph_root, field) = SPLAY_LEFT(node, field);             \
+} while (/*CONSTCOND*/ 0)
+
+/* Generates prototypes and inline functions */
+
+#define SPLAY_PROTOTYPE(name, type, field, cmp)                               \
+void name##_SPLAY(struct name *, struct type *);                              \
+void name##_SPLAY_MINMAX(struct name *, int);                                 \
+struct type *name##_SPLAY_INSERT(struct name *, struct type *);               \
+struct type *name##_SPLAY_REMOVE(struct name *, struct type *);               \
+                                                                              \
+/* Finds the node with the same key as elm */                                 \
+static __inline struct type *                                                 \
+name##_SPLAY_FIND(struct name *head, struct type *elm)                        \
+{                                                                             \
+  if (SPLAY_EMPTY(head))                                                      \
+    return(NULL);                                                             \
+  name##_SPLAY(head, elm);                                                    \
+  if ((cmp)(elm, (head)->sph_root) == 0)                                      \
+    return (head->sph_root);                                                  \
+  return (NULL);                                                              \
+}                                                                             \
+                                                                              \
+static __inline struct type *                                                 \
+name##_SPLAY_NEXT(struct name *head, struct type *elm)                        \
+{                                                                             \
+  name##_SPLAY(head, elm);                                                    \
+  if (SPLAY_RIGHT(elm, field) != NULL) {                                      \
+    elm = SPLAY_RIGHT(elm, field);                                            \
+    while (SPLAY_LEFT(elm, field) != NULL) {                                  \
+      elm = SPLAY_LEFT(elm, field);                                           \
+    }                                                                         \
+  } else                                                                      \
+    elm = NULL;                                                               \
+  return (elm);                                                               \
+}                                                                             \
+                                                                              \
+static __inline struct type *                                                 \
+name##_SPLAY_MIN_MAX(struct name *head, int val)                              \
+{                                                                             \
+  name##_SPLAY_MINMAX(head, val);                                             \
+  return (SPLAY_ROOT(head));                                                  \
+}
+
+/* Main splay operation.
+ * Moves node close to the key of elm to top
+ */
+#define SPLAY_GENERATE(name, type, field, cmp)                                \
+struct type *                                                                 \
+name##_SPLAY_INSERT(struct name *head, struct type *elm)                      \
+{                                                                             \
+    if (SPLAY_EMPTY(head)) {                                                  \
+      SPLAY_LEFT(elm, field) = SPLAY_RIGHT(elm, field) = NULL;                \
+    } else {                                                                  \
+      int __comp;                                                             \
+      name##_SPLAY(head, elm);                                                \
+      __comp = (cmp)(elm, (head)->sph_root);                                  \
+      if(__comp < 0) {                                                        \
+        SPLAY_LEFT(elm, field) = SPLAY_LEFT((head)->sph_root, field);         \
+        SPLAY_RIGHT(elm, field) = (head)->sph_root;                           \
+        SPLAY_LEFT((head)->sph_root, field) = NULL;                           \
+      } else if (__comp > 0) {                                                \
+        SPLAY_RIGHT(elm, field) = SPLAY_RIGHT((head)->sph_root, field);       \
+        SPLAY_LEFT(elm, field) = (head)->sph_root;                            \
+        SPLAY_RIGHT((head)->sph_root, field) = NULL;                          \
+      } else                                                                  \
+        return ((head)->sph_root);                                            \
+    }                                                                         \
+    (head)->sph_root = (elm);                                                 \
+    return (NULL);                                                            \
+}                                                                             \
+                                                                              \
+struct type *                                                                 \
+name##_SPLAY_REMOVE(struct name *head, struct type *elm)                      \
+{                                                                             \
+  struct type *__tmp;                                                         \
+  if (SPLAY_EMPTY(head))                                                      \
+    return (NULL);                                                            \
+  name##_SPLAY(head, elm);                                                    \
+  if ((cmp)(elm, (head)->sph_root) == 0) {                                    \
+    if (SPLAY_LEFT((head)->sph_root, field) == NULL) {                        \
+      (head)->sph_root = SPLAY_RIGHT((head)->sph_root, field);                \
+    } else {                                                                  \
+      __tmp = SPLAY_RIGHT((head)->sph_root, field);                           \
+      (head)->sph_root = SPLAY_LEFT((head)->sph_root, field);                 \
+      name##_SPLAY(head, elm);                                                \
+      SPLAY_RIGHT((head)->sph_root, field) = __tmp;                           \
+    }                                                                         \
+    return (elm);                                                             \
+  }                                                                           \
+  return (NULL);                                                              \
+}                                                                             \
+                                                                              \
+void                                                                          \
+name##_SPLAY(struct name *head, struct type *elm)                             \
+{                                                                             \
+  struct type __node, *__left, *__right, *__tmp;                              \
+  int __comp;                                                                 \
+                                                                              \
+  SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = NULL;            \
+  __left = __right = &__node;                                                 \
+                                                                              \
+  while ((__comp = (cmp)(elm, (head)->sph_root)) != 0) {                      \
+    if (__comp < 0) {                                                         \
+      __tmp = SPLAY_LEFT((head)->sph_root, field);                            \
+      if (__tmp == NULL)                                                      \
+        break;                                                                \
+      if ((cmp)(elm, __tmp) < 0){                                             \
+        SPLAY_ROTATE_RIGHT(head, __tmp, field);                               \
+        if (SPLAY_LEFT((head)->sph_root, field) == NULL)                      \
+          break;                                                              \
+      }                                                                       \
+      SPLAY_LINKLEFT(head, __right, field);                                   \
+    } else if (__comp > 0) {                                                  \
+      __tmp = SPLAY_RIGHT((head)->sph_root, field);                           \
+      if (__tmp == NULL)                                                      \
+        break;                                                                \
+      if ((cmp)(elm, __tmp) > 0){                                             \
+        SPLAY_ROTATE_LEFT(head, __tmp, field);                                \
+        if (SPLAY_RIGHT((head)->sph_root, field) == NULL)                     \
+          break;                                                              \
+      }                                                                       \
+      SPLAY_LINKRIGHT(head, __left, field);                                   \
+    }                                                                         \
+  }                                                                           \
+  SPLAY_ASSEMBLE(head, &__node, __left, __right, field);                      \
+}                                                                             \
+                                                                              \
+/* Splay with either the minimum or the maximum element                       \
+ * Used to find minimum or maximum element in tree.                           \
+ */                                                                           \
+void name##_SPLAY_MINMAX(struct name *head, int __comp)                       \
+{                                                                             \
+  struct type __node, *__left, *__right, *__tmp;                              \
+                                                                              \
+  SPLAY_LEFT(&__node, field) = SPLAY_RIGHT(&__node, field) = NULL;            \
+  __left = __right = &__node;                                                 \
+                                                                              \
+  while (1) {                                                                 \
+    if (__comp < 0) {                                                         \
+      __tmp = SPLAY_LEFT((head)->sph_root, field);                            \
+      if (__tmp == NULL)                                                      \
+        break;                                                                \
+      if (__comp < 0){                                                        \
+        SPLAY_ROTATE_RIGHT(head, __tmp, field);                               \
+        if (SPLAY_LEFT((head)->sph_root, field) == NULL)                      \
+          break;                                                              \
+      }                                                                       \
+      SPLAY_LINKLEFT(head, __right, field);                                   \
+    } else if (__comp > 0) {                                                  \
+      __tmp = SPLAY_RIGHT((head)->sph_root, field);                           \
+      if (__tmp == NULL)                                                      \
+        break;                                                                \
+      if (__comp > 0) {                                                       \
+        SPLAY_ROTATE_LEFT(head, __tmp, field);                                \
+        if (SPLAY_RIGHT((head)->sph_root, field) == NULL)                     \
+          break;                                                              \
+      }                                                                       \
+      SPLAY_LINKRIGHT(head, __left, field);                                   \
+    }                                                                         \
+  }                                                                           \
+  SPLAY_ASSEMBLE(head, &__node, __left, __right, field);                      \
+}
+
+#define SPLAY_NEGINF  -1
+#define SPLAY_INF     1
+
+#define SPLAY_INSERT(name, x, y)  name##_SPLAY_INSERT(x, y)
+#define SPLAY_REMOVE(name, x, y)  name##_SPLAY_REMOVE(x, y)
+#define SPLAY_FIND(name, x, y)    name##_SPLAY_FIND(x, y)
+#define SPLAY_NEXT(name, x, y)    name##_SPLAY_NEXT(x, y)
+#define SPLAY_MIN(name, x)        (SPLAY_EMPTY(x) ? NULL                      \
+                                  : name##_SPLAY_MIN_MAX(x, SPLAY_NEGINF))
+#define SPLAY_MAX(name, x)        (SPLAY_EMPTY(x) ? NULL                      \
+                                  : name##_SPLAY_MIN_MAX(x, SPLAY_INF))
+
+#define SPLAY_FOREACH(x, name, head)                                          \
+  for ((x) = SPLAY_MIN(name, head);                                           \
+       (x) != NULL;                                                           \
+       (x) = SPLAY_NEXT(name, head, x))
+
+/* Macros that define a red-black tree */
+#define RB_HEAD(name, type)                                                   \
+struct name {                                                                 \
+  struct type *rbh_root; /* root of the tree */                               \
+}
+
+#define RB_INITIALIZER(root)                                                  \
+  { NULL }
+
+#define RB_INIT(root) do {                                                    \
+  (root)->rbh_root = NULL;                                                    \
+} while (/*CONSTCOND*/ 0)
+
+#define RB_BLACK  0
+#define RB_RED    1
+#define RB_ENTRY(type)                                                        \
+struct {                                                                      \
+  struct type *rbe_left;        /* left element */                            \
+  struct type *rbe_right;       /* right element */                           \
+  struct type *rbe_parent;      /* parent element */                          \
+  int rbe_color;                /* node color */                              \
+}
+
+#define RB_LEFT(elm, field)     (elm)->field.rbe_left
+#define RB_RIGHT(elm, field)    (elm)->field.rbe_right
+#define RB_PARENT(elm, field)   (elm)->field.rbe_parent
+#define RB_COLOR(elm, field)    (elm)->field.rbe_color
+#define RB_ROOT(head)           (head)->rbh_root
+#define RB_EMPTY(head)          (RB_ROOT(head) == NULL)
+
+#define RB_SET(elm, parent, field) do {                                       \
+  RB_PARENT(elm, field) = parent;                                             \
+  RB_LEFT(elm, field) = RB_RIGHT(elm, field) = NULL;                          \
+  RB_COLOR(elm, field) = RB_RED;                                              \
+} while (/*CONSTCOND*/ 0)
+
+#define RB_SET_BLACKRED(black, red, field) do {                               \
+  RB_COLOR(black, field) = RB_BLACK;                                          \
+  RB_COLOR(red, field) = RB_RED;                                              \
+} while (/*CONSTCOND*/ 0)
+
+#ifndef RB_AUGMENT
+#define RB_AUGMENT(x)  do {} while (0)
+#endif
+
+#define RB_ROTATE_LEFT(head, elm, tmp, field) do {                            \
+  (tmp) = RB_RIGHT(elm, field);                                               \
+  if ((RB_RIGHT(elm, field) = RB_LEFT(tmp, field)) != NULL) {                 \
+    RB_PARENT(RB_LEFT(tmp, field), field) = (elm);                            \
+  }                                                                           \
+  RB_AUGMENT(elm);                                                            \
+  if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) != NULL) {              \
+    if ((elm) == RB_LEFT(RB_PARENT(elm, field), field))                       \
+      RB_LEFT(RB_PARENT(elm, field), field) = (tmp);                          \
+    else                                                                      \
+      RB_RIGHT(RB_PARENT(elm, field), field) = (tmp);                         \
+  } else                                                                      \
+    (head)->rbh_root = (tmp);                                                 \
+  RB_LEFT(tmp, field) = (elm);                                                \
+  RB_PARENT(elm, field) = (tmp);                                              \
+  RB_AUGMENT(tmp);                                                            \
+  if ((RB_PARENT(tmp, field)))                                                \
+    RB_AUGMENT(RB_PARENT(tmp, field));                                        \
+} while (/*CONSTCOND*/ 0)
+
+#define RB_ROTATE_RIGHT(head, elm, tmp, field) do {                           \
+  (tmp) = RB_LEFT(elm, field);                                                \
+  if ((RB_LEFT(elm, field) = RB_RIGHT(tmp, field)) != NULL) {                 \
+    RB_PARENT(RB_RIGHT(tmp, field), field) = (elm);                           \
+  }                                                                           \
+  RB_AUGMENT(elm);                                                            \
+  if ((RB_PARENT(tmp, field) = RB_PARENT(elm, field)) != NULL) {              \
+    if ((elm) == RB_LEFT(RB_PARENT(elm, field), field))                       \
+      RB_LEFT(RB_PARENT(elm, field), field) = (tmp);                          \
+    else                                                                      \
+      RB_RIGHT(RB_PARENT(elm, field), field) = (tmp);                         \
+  } else                                                                      \
+    (head)->rbh_root = (tmp);                                                 \
+  RB_RIGHT(tmp, field) = (elm);                                               \
+  RB_PARENT(elm, field) = (tmp);                                              \
+  RB_AUGMENT(tmp);                                                            \
+  if ((RB_PARENT(tmp, field)))                                                \
+    RB_AUGMENT(RB_PARENT(tmp, field));                                        \
+} while (/*CONSTCOND*/ 0)
+
+/* Generates prototypes and inline functions */
+#define  RB_PROTOTYPE(name, type, field, cmp)                                 \
+  RB_PROTOTYPE_INTERNAL(name, type, field, cmp,)
+#define  RB_PROTOTYPE_STATIC(name, type, field, cmp)                          \
+  RB_PROTOTYPE_INTERNAL(name, type, field, cmp, UV__UNUSED static)
+#define RB_PROTOTYPE_INTERNAL(name, type, field, cmp, attr)                   \
+attr void name##_RB_INSERT_COLOR(struct name *, struct type *);               \
+attr void name##_RB_REMOVE_COLOR(struct name *, struct type *, struct type *);\
+attr struct type *name##_RB_REMOVE(struct name *, struct type *);             \
+attr struct type *name##_RB_INSERT(struct name *, struct type *);             \
+attr struct type *name##_RB_FIND(struct name *, struct type *);               \
+attr struct type *name##_RB_NFIND(struct name *, struct type *);              \
+attr struct type *name##_RB_NEXT(struct type *);                              \
+attr struct type *name##_RB_PREV(struct type *);                              \
+attr struct type *name##_RB_MINMAX(struct name *, int);                       \
+                                                                              \
+
+/* Main rb operation.
+ * Moves node close to the key of elm to top
+ */
+#define  RB_GENERATE(name, type, field, cmp)                                  \
+  RB_GENERATE_INTERNAL(name, type, field, cmp,)
+#define  RB_GENERATE_STATIC(name, type, field, cmp)                           \
+  RB_GENERATE_INTERNAL(name, type, field, cmp, UV__UNUSED static)
+#define RB_GENERATE_INTERNAL(name, type, field, cmp, attr)                    \
+attr void                                                                     \
+name##_RB_INSERT_COLOR(struct name *head, struct type *elm)                   \
+{                                                                             \
+  struct type *parent, *gparent, *tmp;                                        \
+  while ((parent = RB_PARENT(elm, field)) != NULL &&                          \
+      RB_COLOR(parent, field) == RB_RED) {                                    \
+    gparent = RB_PARENT(parent, field);                                       \
+    if (parent == RB_LEFT(gparent, field)) {                                  \
+      tmp = RB_RIGHT(gparent, field);                                         \
+      if (tmp && RB_COLOR(tmp, field) == RB_RED) {                            \
+        RB_COLOR(tmp, field) = RB_BLACK;                                      \
+        RB_SET_BLACKRED(parent, gparent, field);                              \
+        elm = gparent;                                                        \
+        continue;                                                             \
+      }                                                                       \
+      if (RB_RIGHT(parent, field) == elm) {                                   \
+        RB_ROTATE_LEFT(head, parent, tmp, field);                             \
+        tmp = parent;                                                         \
+        parent = elm;                                                         \
+        elm = tmp;                                                            \
+      }                                                                       \
+      RB_SET_BLACKRED(parent, gparent, field);                                \
+      RB_ROTATE_RIGHT(head, gparent, tmp, field);                             \
+    } else {                                                                  \
+      tmp = RB_LEFT(gparent, field);                                          \
+      if (tmp && RB_COLOR(tmp, field) == RB_RED) {                            \
+        RB_COLOR(tmp, field) = RB_BLACK;                                      \
+        RB_SET_BLACKRED(parent, gparent, field);                              \
+        elm = gparent;                                                        \
+        continue;                                                             \
+      }                                                                       \
+      if (RB_LEFT(parent, field) == elm) {                                    \
+        RB_ROTATE_RIGHT(head, parent, tmp, field);                            \
+        tmp = parent;                                                         \
+        parent = elm;                                                         \
+        elm = tmp;                                                            \
+      }                                                                       \
+      RB_SET_BLACKRED(parent, gparent, field);                                \
+      RB_ROTATE_LEFT(head, gparent, tmp, field);                              \
+    }                                                                         \
+  }                                                                           \
+  RB_COLOR(head->rbh_root, field) = RB_BLACK;                                 \
+}                                                                             \
+                                                                              \
+attr void                                                                     \
+name##_RB_REMOVE_COLOR(struct name *head, struct type *parent,                \
+    struct type *elm)                                                         \
+{                                                                             \
+  struct type *tmp;                                                           \
+  while ((elm == NULL || RB_COLOR(elm, field) == RB_BLACK) &&                 \
+      elm != RB_ROOT(head)) {                                                 \
+    if (RB_LEFT(parent, field) == elm) {                                      \
+      tmp = RB_RIGHT(parent, field);                                          \
+      if (RB_COLOR(tmp, field) == RB_RED) {                                   \
+        RB_SET_BLACKRED(tmp, parent, field);                                  \
+        RB_ROTATE_LEFT(head, parent, tmp, field);                             \
+        tmp = RB_RIGHT(parent, field);                                        \
+      }                                                                       \
+      if ((RB_LEFT(tmp, field) == NULL ||                                     \
+          RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&                \
+          (RB_RIGHT(tmp, field) == NULL ||                                    \
+          RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {               \
+        RB_COLOR(tmp, field) = RB_RED;                                        \
+        elm = parent;                                                         \
+        parent = RB_PARENT(elm, field);                                       \
+      } else {                                                                \
+        if (RB_RIGHT(tmp, field) == NULL ||                                   \
+            RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK) {              \
+          struct type *oleft;                                                 \
+          if ((oleft = RB_LEFT(tmp, field))                                   \
+              != NULL)                                                        \
+            RB_COLOR(oleft, field) = RB_BLACK;                                \
+          RB_COLOR(tmp, field) = RB_RED;                                      \
+          RB_ROTATE_RIGHT(head, tmp, oleft, field);                           \
+          tmp = RB_RIGHT(parent, field);                                      \
+        }                                                                     \
+        RB_COLOR(tmp, field) = RB_COLOR(parent, field);                       \
+        RB_COLOR(parent, field) = RB_BLACK;                                   \
+        if (RB_RIGHT(tmp, field))                                             \
+          RB_COLOR(RB_RIGHT(tmp, field), field) = RB_BLACK;                   \
+        RB_ROTATE_LEFT(head, parent, tmp, field);                             \
+        elm = RB_ROOT(head);                                                  \
+        break;                                                                \
+      }                                                                       \
+    } else {                                                                  \
+      tmp = RB_LEFT(parent, field);                                           \
+      if (RB_COLOR(tmp, field) == RB_RED) {                                   \
+        RB_SET_BLACKRED(tmp, parent, field);                                  \
+        RB_ROTATE_RIGHT(head, parent, tmp, field);                            \
+        tmp = RB_LEFT(parent, field);                                         \
+      }                                                                       \
+      if ((RB_LEFT(tmp, field) == NULL ||                                     \
+          RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) &&                \
+          (RB_RIGHT(tmp, field) == NULL ||                                    \
+          RB_COLOR(RB_RIGHT(tmp, field), field) == RB_BLACK)) {               \
+        RB_COLOR(tmp, field) = RB_RED;                                        \
+        elm = parent;                                                         \
+        parent = RB_PARENT(elm, field);                                       \
+      } else {                                                                \
+        if (RB_LEFT(tmp, field) == NULL ||                                    \
+            RB_COLOR(RB_LEFT(tmp, field), field) == RB_BLACK) {               \
+          struct type *oright;                                                \
+          if ((oright = RB_RIGHT(tmp, field))                                 \
+              != NULL)                                                        \
+            RB_COLOR(oright, field) = RB_BLACK;                               \
+          RB_COLOR(tmp, field) = RB_RED;                                      \
+          RB_ROTATE_LEFT(head, tmp, oright, field);                           \
+          tmp = RB_LEFT(parent, field);                                       \
+        }                                                                     \
+        RB_COLOR(tmp, field) = RB_COLOR(parent, field);                       \
+        RB_COLOR(parent, field) = RB_BLACK;                                   \
+        if (RB_LEFT(tmp, field))                                              \
+          RB_COLOR(RB_LEFT(tmp, field), field) = RB_BLACK;                    \
+        RB_ROTATE_RIGHT(head, parent, tmp, field);                            \
+        elm = RB_ROOT(head);                                                  \
+        break;                                                                \
+      }                                                                       \
+    }                                                                         \
+  }                                                                           \
+  if (elm)                                                                    \
+    RB_COLOR(elm, field) = RB_BLACK;                                          \
+}                                                                             \
+                                                                              \
+attr struct type *                                                            \
+name##_RB_REMOVE(struct name *head, struct type *elm)                         \
+{                                                                             \
+  struct type *child, *parent, *old = elm;                                    \
+  int color;                                                                  \
+  if (RB_LEFT(elm, field) == NULL)                                            \
+    child = RB_RIGHT(elm, field);                                             \
+  else if (RB_RIGHT(elm, field) == NULL)                                      \
+    child = RB_LEFT(elm, field);                                              \
+  else {                                                                      \
+    struct type *left;                                                        \
+    elm = RB_RIGHT(elm, field);                                               \
+    while ((left = RB_LEFT(elm, field)) != NULL)                              \
+      elm = left;                                                             \
+    child = RB_RIGHT(elm, field);                                             \
+    parent = RB_PARENT(elm, field);                                           \
+    color = RB_COLOR(elm, field);                                             \
+    if (child)                                                                \
+      RB_PARENT(child, field) = parent;                                       \
+    if (parent) {                                                             \
+      if (RB_LEFT(parent, field) == elm)                                      \
+        RB_LEFT(parent, field) = child;                                       \
+      else                                                                    \
+        RB_RIGHT(parent, field) = child;                                      \
+      RB_AUGMENT(parent);                                                     \
+    } else                                                                    \
+      RB_ROOT(head) = child;                                                  \
+    if (RB_PARENT(elm, field) == old)                                         \
+      parent = elm;                                                           \
+    (elm)->field = (old)->field;                                              \
+    if (RB_PARENT(old, field)) {                                              \
+      if (RB_LEFT(RB_PARENT(old, field), field) == old)                       \
+        RB_LEFT(RB_PARENT(old, field), field) = elm;                          \
+      else                                                                    \
+        RB_RIGHT(RB_PARENT(old, field), field) = elm;                         \
+      RB_AUGMENT(RB_PARENT(old, field));                                      \
+    } else                                                                    \
+      RB_ROOT(head) = elm;                                                    \
+    RB_PARENT(RB_LEFT(old, field), field) = elm;                              \
+    if (RB_RIGHT(old, field))                                                 \
+      RB_PARENT(RB_RIGHT(old, field), field) = elm;                           \
+    if (parent) {                                                             \
+      left = parent;                                                          \
+      do {                                                                    \
+        RB_AUGMENT(left);                                                     \
+      } while ((left = RB_PARENT(left, field)) != NULL);                      \
+    }                                                                         \
+    goto color;                                                               \
+  }                                                                           \
+  parent = RB_PARENT(elm, field);                                             \
+  color = RB_COLOR(elm, field);                                               \
+  if (child)                                                                  \
+    RB_PARENT(child, field) = parent;                                         \
+  if (parent) {                                                               \
+    if (RB_LEFT(parent, field) == elm)                                        \
+      RB_LEFT(parent, field) = child;                                         \
+    else                                                                      \
+      RB_RIGHT(parent, field) = child;                                        \
+    RB_AUGMENT(parent);                                                       \
+  } else                                                                      \
+    RB_ROOT(head) = child;                                                    \
+color:                                                                        \
+  if (color == RB_BLACK)                                                      \
+    name##_RB_REMOVE_COLOR(head, parent, child);                              \
+  return (old);                                                               \
+}                                                                             \
+                                                                              \
+/* Inserts a node into the RB tree */                                         \
+attr struct type *                                                            \
+name##_RB_INSERT(struct name *head, struct type *elm)                         \
+{                                                                             \
+  struct type *tmp;                                                           \
+  struct type *parent = NULL;                                                 \
+  int comp = 0;                                                               \
+  tmp = RB_ROOT(head);                                                        \
+  while (tmp) {                                                               \
+    parent = tmp;                                                             \
+    comp = (cmp)(elm, parent);                                                \
+    if (comp < 0)                                                             \
+      tmp = RB_LEFT(tmp, field);                                              \
+    else if (comp > 0)                                                        \
+      tmp = RB_RIGHT(tmp, field);                                             \
+    else                                                                      \
+      return (tmp);                                                           \
+  }                                                                           \
+  RB_SET(elm, parent, field);                                                 \
+  if (parent != NULL) {                                                       \
+    if (comp < 0)                                                             \
+      RB_LEFT(parent, field) = elm;                                           \
+    else                                                                      \
+      RB_RIGHT(parent, field) = elm;                                          \
+    RB_AUGMENT(parent);                                                       \
+  } else                                                                      \
+    RB_ROOT(head) = elm;                                                      \
+  name##_RB_INSERT_COLOR(head, elm);                                          \
+  return (NULL);                                                              \
+}                                                                             \
+                                                                              \
+/* Finds the node with the same key as elm */                                 \
+attr struct type *                                                            \
+name##_RB_FIND(struct name *head, struct type *elm)                           \
+{                                                                             \
+  struct type *tmp = RB_ROOT(head);                                           \
+  int comp;                                                                   \
+  while (tmp) {                                                               \
+    comp = cmp(elm, tmp);                                                     \
+    if (comp < 0)                                                             \
+      tmp = RB_LEFT(tmp, field);                                              \
+    else if (comp > 0)                                                        \
+      tmp = RB_RIGHT(tmp, field);                                             \
+    else                                                                      \
+      return (tmp);                                                           \
+  }                                                                           \
+  return (NULL);                                                              \
+}                                                                             \
+                                                                              \
+/* Finds the first node greater than or equal to the search key */            \
+attr struct type *                                                            \
+name##_RB_NFIND(struct name *head, struct type *elm)                          \
+{                                                                             \
+  struct type *tmp = RB_ROOT(head);                                           \
+  struct type *res = NULL;                                                    \
+  int comp;                                                                   \
+  while (tmp) {                                                               \
+    comp = cmp(elm, tmp);                                                     \
+    if (comp < 0) {                                                           \
+      res = tmp;                                                              \
+      tmp = RB_LEFT(tmp, field);                                              \
+    }                                                                         \
+    else if (comp > 0)                                                        \
+      tmp = RB_RIGHT(tmp, field);                                             \
+    else                                                                      \
+      return (tmp);                                                           \
+  }                                                                           \
+  return (res);                                                               \
+}                                                                             \
+                                                                              \
+/* ARGSUSED */                                                                \
+attr struct type *                                                            \
+name##_RB_NEXT(struct type *elm)                                              \
+{                                                                             \
+  if (RB_RIGHT(elm, field)) {                                                 \
+    elm = RB_RIGHT(elm, field);                                               \
+    while (RB_LEFT(elm, field))                                               \
+      elm = RB_LEFT(elm, field);                                              \
+  } else {                                                                    \
+    if (RB_PARENT(elm, field) &&                                              \
+        (elm == RB_LEFT(RB_PARENT(elm, field), field)))                       \
+      elm = RB_PARENT(elm, field);                                            \
+    else {                                                                    \
+      while (RB_PARENT(elm, field) &&                                         \
+          (elm == RB_RIGHT(RB_PARENT(elm, field), field)))                    \
+        elm = RB_PARENT(elm, field);                                          \
+      elm = RB_PARENT(elm, field);                                            \
+    }                                                                         \
+  }                                                                           \
+  return (elm);                                                               \
+}                                                                             \
+                                                                              \
+/* ARGSUSED */                                                                \
+attr struct type *                                                            \
+name##_RB_PREV(struct type *elm)                                              \
+{                                                                             \
+  if (RB_LEFT(elm, field)) {                                                  \
+    elm = RB_LEFT(elm, field);                                                \
+    while (RB_RIGHT(elm, field))                                              \
+      elm = RB_RIGHT(elm, field);                                             \
+  } else {                                                                    \
+    if (RB_PARENT(elm, field) &&                                              \
+        (elm == RB_RIGHT(RB_PARENT(elm, field), field)))                      \
+      elm = RB_PARENT(elm, field);                                            \
+    else {                                                                    \
+      while (RB_PARENT(elm, field) &&                                         \
+          (elm == RB_LEFT(RB_PARENT(elm, field), field)))                     \
+        elm = RB_PARENT(elm, field);                                          \
+      elm = RB_PARENT(elm, field);                                            \
+    }                                                                         \
+  }                                                                           \
+  return (elm);                                                               \
+}                                                                             \
+                                                                              \
+attr struct type *                                                            \
+name##_RB_MINMAX(struct name *head, int val)                                  \
+{                                                                             \
+  struct type *tmp = RB_ROOT(head);                                           \
+  struct type *parent = NULL;                                                 \
+  while (tmp) {                                                               \
+    parent = tmp;                                                             \
+    if (val < 0)                                                              \
+      tmp = RB_LEFT(tmp, field);                                              \
+    else                                                                      \
+      tmp = RB_RIGHT(tmp, field);                                             \
+  }                                                                           \
+  return (parent);                                                            \
+}
+
+#define RB_NEGINF   -1
+#define RB_INF      1
+
+#define RB_INSERT(name, x, y)   name##_RB_INSERT(x, y)
+#define RB_REMOVE(name, x, y)   name##_RB_REMOVE(x, y)
+#define RB_FIND(name, x, y)     name##_RB_FIND(x, y)
+#define RB_NFIND(name, x, y)    name##_RB_NFIND(x, y)
+#define RB_NEXT(name, x, y)     name##_RB_NEXT(y)
+#define RB_PREV(name, x, y)     name##_RB_PREV(y)
+#define RB_MIN(name, x)         name##_RB_MINMAX(x, RB_NEGINF)
+#define RB_MAX(name, x)         name##_RB_MINMAX(x, RB_INF)
+
+#define RB_FOREACH(x, name, head)                                             \
+  for ((x) = RB_MIN(name, head);                                              \
+       (x) != NULL;                                                           \
+       (x) = name##_RB_NEXT(x))
+
+#define RB_FOREACH_FROM(x, name, y)                                           \
+  for ((x) = (y);                                                             \
+      ((x) != NULL) && ((y) = name##_RB_NEXT(x), (x) != NULL);                \
+       (x) = (y))
+
+#define RB_FOREACH_SAFE(x, name, head, y)                                     \
+  for ((x) = RB_MIN(name, head);                                              \
+      ((x) != NULL) && ((y) = name##_RB_NEXT(x), (x) != NULL);                \
+       (x) = (y))
+
+#define RB_FOREACH_REVERSE(x, name, head)                                     \
+  for ((x) = RB_MAX(name, head);                                              \
+       (x) != NULL;                                                           \
+       (x) = name##_RB_PREV(x))
+
+#define RB_FOREACH_REVERSE_FROM(x, name, y)                                   \
+  for ((x) = (y);                                                             \
+      ((x) != NULL) && ((y) = name##_RB_PREV(x), (x) != NULL);                \
+       (x) = (y))
+
+#define RB_FOREACH_REVERSE_SAFE(x, name, head, y)                             \
+  for ((x) = RB_MAX(name, head);                                              \
+      ((x) != NULL) && ((y) = name##_RB_PREV(x), (x) != NULL);                \
+       (x) = (y))
+
+#endif  /* UV_TREE_H_ */