Nginx之红黑树
Nginx之红黑树
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #ifndef _NGX_RBTREE_H_INCLUDED_ #define _NGX_RBTREE_H_INCLUDED_ #include <ngx_config.h> #include <ngx_core.h> typedef ngx_uint_t ngx_rbtree_key_t; typedef ngx_int_t ngx_rbtree_key_int_t; typedef struct ngx_rbtree_node_s ngx_rbtree_node_t; // 红黑树 struct ngx_rbtree_node_s { // 无符号整形的关键字 ngx_rbtree_key_t key; // 左子节点 ngx_rbtree_node_t *left; // 右子节点 ngx_rbtree_node_t *right; // 父节点 ngx_rbtree_node_t *parent; // 节点的颜色,0表示黑色,1表示红色 u_char color; // 仅1个字节的节点数据。由于表示的空间太小,所以一般很少使用。 u_char data; }; typedef struct ngx_rbtree_s ngx_rbtree_t; typedef void (*ngx_rbtree_insert_pt) (ngx_rbtree_node_t *root, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel); struct ngx_rbtree_s { // 指向树的根节点。 ngx_rbtree_node_t *root; // 指向NIL哨兵节点 ngx_rbtree_node_t *sentinel; // 表示红黑树添加元素的函数指针,它决定在添加新节点时的行为究竟是替换还是新增 ngx_rbtree_insert_pt insert; }; #define ngx_rbtree_init(tree, s, i) \ ngx_rbtree_sentinel_init(s); \ (tree)->root = s; \ (tree)->sentinel = s; \ (tree)->insert = i void ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree, ngx_rbtree_node_t *node); void ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree, ngx_rbtree_node_t *node); void ngx_rbtree_insert_value(ngx_rbtree_node_t *root, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel); void ngx_rbtree_insert_timer_value(ngx_rbtree_node_t *root, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel); #define ngx_rbt_red(node) ((node)->color = 1) #define ngx_rbt_black(node) ((node)->color = 0) #define ngx_rbt_is_red(node) ((node)->color) #define ngx_rbt_is_black(node) (!ngx_rbt_is_red(node)) #define ngx_rbt_copy_color(n1, n2) (n1->color = n2->color) /* a sentinel must be black */ #define ngx_rbtree_sentinel_init(node) ngx_rbt_black(node) static ngx_inline ngx_rbtree_node_t * ngx_rbtree_min(ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { while (node->left != sentinel) { node = node->left; } return node; } #endif /* _NGX_RBTREE_H_INCLUDED_ */ /* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> /* * The red-black tree code is based on the algorithm described in * the "Introduction to Algorithms" by Cormen, Leiserson and Rivest. */ static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node); static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node); void ngx_rbtree_insert(ngx_thread_volatile ngx_rbtree_t *tree, ngx_rbtree_node_t *node) { ngx_rbtree_node_t **root, *temp, *sentinel; /* a binary tree insert */ root = (ngx_rbtree_node_t **) &tree->root; sentinel = tree->sentinel; if (*root == sentinel) { //空树 node->parent = NULL; node->left = sentinel; node->right = sentinel; ngx_rbt_black(node); *root = node; return; } tree->insert(*root, node, sentinel); /* re-balance tree */ while (node != *root && ngx_rbt_is_red(node->parent)) { if (node->parent == node->parent->parent->left) { temp = node->parent->parent->right; if (ngx_rbt_is_red(temp)) { ngx_rbt_black(node->parent); ngx_rbt_black(temp); ngx_rbt_red(node->parent->parent); node = node->parent->parent; } else { if (node == node->parent->right) { node = node->parent; ngx_rbtree_left_rotate(root, sentinel, node); } ngx_rbt_black(node->parent); ngx_rbt_red(node->parent->parent); ngx_rbtree_right_rotate(root, sentinel, node->parent->parent); } } else { temp = node->parent->parent->left; if (ngx_rbt_is_red(temp)) { ngx_rbt_black(node->parent); ngx_rbt_black(temp); ngx_rbt_red(node->parent->parent); node = node->parent->parent; } else { if (node == node->parent->left) { node = node->parent; ngx_rbtree_right_rotate(root, sentinel, node); } ngx_rbt_black(node->parent); ngx_rbt_red(node->parent->parent); ngx_rbtree_left_rotate(root, sentinel, node->parent->parent); } } } ngx_rbt_black(*root); } void ngx_rbtree_insert_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; for (;;) { p = (node->key < temp->key) ? &temp->left : &temp->right; if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } void ngx_rbtree_insert_timer_value(ngx_rbtree_node_t *temp, ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel) { ngx_rbtree_node_t **p; for (;;) { /* * Timer values * 1) are spread in small range, usually several minutes, * 2) and overflow each 49 days, if milliseconds are stored in 32 bits. * The comparison takes into account that overflow. */ /* node->key < temp->key */ p = ((ngx_rbtree_key_int_t) node->key - (ngx_rbtree_key_int_t) temp->key < 0) ? &temp->left : &temp->right; if (*p == sentinel) { break; } temp = *p; } *p = node; node->parent = temp; node->left = sentinel; node->right = sentinel; ngx_rbt_red(node); } void ngx_rbtree_delete(ngx_thread_volatile ngx_rbtree_t *tree, ngx_rbtree_node_t *node) { ngx_uint_t red; ngx_rbtree_node_t **root, *sentinel, *subst, *temp, *w; /* a binary tree delete */ root = (ngx_rbtree_node_t **) &tree->root; sentinel = tree->sentinel; //找到y和x节点 if (node->left == sentinel) { temp = node->right; subst = node; } else if (node->right == sentinel) { temp = node->left; subst = node; } else { subst = ngx_rbtree_min(node->right, sentinel); if (subst->left != sentinel) { temp = subst->left; } else { temp = subst->right; } } //y节点为root节点 if (subst == *root) { *root = temp; ngx_rbt_black(temp); /* DEBUG stuff */ node->left = NULL; node->right = NULL; node->parent = NULL; node->key = 0; return; } // red = ngx_rbt_is_red(subst);//记录y节点颜色 //y父的孩子节点 if (subst == subst->parent->left) { subst->parent->left = temp; } else { subst->parent->right = temp; } //y孩子的父节点 if (subst == node) {//只有一个孩子节点 temp->parent = subst->parent; } else { if (subst->parent == node) { temp->parent = subst; } else { temp->parent = subst->parent; } //y节点copy z节点属性 subst->left = node->left; subst->right = node->right; subst->parent = node->parent; ngx_rbt_copy_color(subst, node); if (node == *root) { *root = subst; } else {//删除节点的父节点的孩子节点 if (node == node->parent->left) { node->parent->left = subst; } else { node->parent->right = subst; } } //y节点的父节点 if (subst->left != sentinel) { subst->left->parent = subst; } if (subst->right != sentinel) { subst->right->parent = subst; } } /* DEBUG stuff */ node->left = NULL; node->right = NULL; node->parent = NULL; node->key = 0; if (red) { return; } /* a delete fixup */ while (temp != *root && ngx_rbt_is_black(temp)) { if (temp == temp->parent->left) { w = temp->parent->right; if (ngx_rbt_is_red(w)) { ngx_rbt_black(w); ngx_rbt_red(temp->parent); ngx_rbtree_left_rotate(root, sentinel, temp->parent); w = temp->parent->right; } if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) { ngx_rbt_red(w); temp = temp->parent; } else { if (ngx_rbt_is_black(w->right)) { ngx_rbt_black(w->left); ngx_rbt_red(w); ngx_rbtree_right_rotate(root, sentinel, w); w = temp->parent->right; } ngx_rbt_copy_color(w, temp->parent); ngx_rbt_black(temp->parent); ngx_rbt_black(w->right); ngx_rbtree_left_rotate(root, sentinel, temp->parent); temp = *root; } } else { w = temp->parent->left; if (ngx_rbt_is_red(w)) { ngx_rbt_black(w); ngx_rbt_red(temp->parent); ngx_rbtree_right_rotate(root, sentinel, temp->parent); w = temp->parent->left; } if (ngx_rbt_is_black(w->left) && ngx_rbt_is_black(w->right)) { ngx_rbt_red(w); temp = temp->parent; } else { if (ngx_rbt_is_black(w->left)) { ngx_rbt_black(w->right); ngx_rbt_red(w); ngx_rbtree_left_rotate(root, sentinel, w); w = temp->parent->left; } ngx_rbt_copy_color(w, temp->parent); ngx_rbt_black(temp->parent); ngx_rbt_black(w->left); ngx_rbtree_right_rotate(root, sentinel, temp->parent); temp = *root; } } } ngx_rbt_black(temp); } static ngx_inline void ngx_rbtree_left_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node) { ngx_rbtree_node_t *temp; //1、设置节点y temp = node->right; //2、将y的左子树作为x的右子树 node->right = temp->left; if (temp->left != sentinel) { temp->left->parent = node; } //3、链接y与x的父节点 temp->parent = node->parent; if (node == *root) { *root = temp; } else if (node == node->parent->left) { node->parent->left = temp; } else { node->parent->right = temp; } //4、x作为y的左子树 temp->left = node; node->parent = temp; } static ngx_inline void ngx_rbtree_right_rotate(ngx_rbtree_node_t **root, ngx_rbtree_node_t *sentinel, ngx_rbtree_node_t *node) { ngx_rbtree_node_t *temp; temp = node->left; node->left = temp->right; if (temp->right != sentinel) { temp->right->parent = node; } temp->parent = node->parent; if (node == *root) { *root = temp; } else if (node == node->parent->right) { node->parent->right = temp; } else { node->parent->left = temp; } temp->right = node; node->parent = temp; }
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在 Linux 中,使用以下命令检查 Nginx 是否已启动:systemctl status nginx根据命令输出进行判断:如果显示 "Active: active (running)",则 Nginx 已启动。如果显示 "Active: inactive (dead)",则 Nginx 已停止。

如何在 Windows 中配置 Nginx?安装 Nginx 并创建虚拟主机配置。修改主配置文件并包含虚拟主机配置。启动或重新加载 Nginx。测试配置并查看网站。选择性启用 SSL 并配置 SSL 证书。选择性设置防火墙允许 80 和 443 端口流量。

确认 Nginx 是否启动的方法:1. 使用命令行:systemctl status nginx(Linux/Unix)、netstat -ano | findstr 80(Windows);2. 检查端口 80 是否开放;3. 查看系统日志中 Nginx 启动消息;4. 使用第三方工具,如 Nagios、Zabbix、Icinga。

在 Linux 中启动 Nginx 的步骤:检查 Nginx 是否已安装。使用 systemctl start nginx 启动 Nginx 服务。使用 systemctl enable nginx 启用在系统启动时自动启动 Nginx。使用 systemctl status nginx 验证启动是否成功。在 Web 浏览器中访问 http://localhost 查看默认欢迎页面。

如何解决 Nginx 403 Forbidden 错误?检查文件或目录权限;2. 检查 .htaccess 文件;3. 检查 Nginx 配置文件;4. 重启 Nginx。其他可能原因还包括防火墙规则、SELinux 设置或应用程序问题。

启动 Nginx 服务器需要按照不同操作系统采取不同的步骤:Linux/Unix 系统:安装 Nginx 软件包(例如使用 apt-get 或 yum)。使用 systemctl 启动 Nginx 服务(例如 sudo systemctl start nginx)。Windows 系统:下载并安装 Windows 二进制文件。使用 nginx.exe 可执行文件启动 Nginx(例如 nginx.exe -c conf\nginx.conf)。无论使用哪种操作系统,您都可以通过访问服务器 IP

问题的答案:304 Not Modified 错误表示浏览器已缓存客户端请求的最新资源版本。解决方案:1. 清除浏览器缓存;2. 禁用浏览器缓存;3. 配置 Nginx 允许客户端缓存;4. 检查文件权限;5. 检查文件哈希;6. 禁用 CDN 或反向代理缓存;7. 重启 Nginx。

服务器无权访问所请求的资源,导致 nginx 403 错误。解决方法包括:检查文件权限。检查 .htaccess 配置。检查 nginx 配置。配置 SELinux 权限。检查防火墙规则。排除其他原因,如浏览器问题、服务器故障或其他可能的错误。
