tp5源码分析之模板标签库

标签库，可以用来自定义模板文件中的标签解析方式

在tp5中自定义了内置标签库(Cx.php)

$taglib->__construct()

标签库构造函数，创建标签库对象

public function __construct($template)
    {
        $this->tpl = $template;
    }

2-1 标签库的标签解析

标签库可以用来解析模板文件中的自定义标签

$taglib->parseTag()

public function parseTag(&$content, $lib = "")
    {
        $tags = [];
        $lib  = $lib ? strtolower($lib) . ":" : "";
        foreach ($this->tags as $name => $val) {
            $close                      = !isset($val["close"]) || $val["close"] ? 1 : 0;
            $tags[$close][$lib . $name] = $name;
            if (isset($val["alias"])) {
                // 别名设置
                $array = (array) $val["alias"];
                foreach (explode(",", $array[0]) as $v) {
                    $tags[$close][$lib . $v] = $name;
                }
            }
        }

        // 闭合标签
        if (!empty($tags[1])) {
            $nodes = [];
            $regex = $this->getRegex(array_keys($tags[1]), 1);
            if (preg_match_all($regex, $content, $matches, PREG_SET_ORDER | PREG_OFFSET_CAPTURE)) {
                $right = [];
                foreach ($matches as $match) {
                    if ("" == $match[1][0]) {
                        $name = strtolower($match[2][0]);
                        // 如果有没闭合的标签头则取出最后一个
                        if (!empty($right[$name])) {
                            // $match[0][1]为标签结束符在模板中的位置
                            $nodes[$match[0][1]] = [
                                "name"  => $name,
                                "begin" => array_pop($right[$name]), // 标签开始符
                                "end"   => $match[0], // 标签结束符
                            ];
                        }
                    } else {
                        // 标签头压入栈
                        $right[strtolower($match[1][0])][] = $match[0];
                    }
                }
                unset($right, $matches);
                // 按标签在模板中的位置从后向前排序
                krsort($nodes);
            }

            $break = "<!--###break###--!>";
            if ($nodes) {
                $beginArray = [];
                // 标签替换 从后向前
                foreach ($nodes as $pos => $node) {
                    // 对应的标签名
                    $name  = $tags[1][$node["name"]];
                    $alias = $lib . $name != $node["name"] ? ($lib ? strstr($node["name"], $lib) : $node["name"]) : "";
                    // 解析标签属性
                    $attrs  = $this->parseAttr($node["begin"][0], $name, $alias);
                    $method = "tag" . $name;
                    // 读取标签库中对应的标签内容 replace[0]用来替换标签头，replace[1]用来替换标签尾
                    $replace = explode($break, $this->$method($attrs, $break));
                    if (count($replace) > 1) {
                        while ($beginArray) {
                            $begin = end($beginArray);
                            // 判断当前标签尾的位置是否在栈中最后一个标签头的后面，是则为子标签
                            if ($node["end"][1] > $begin["pos"]) {
                                break;
                            } else {
                                // 不为子标签时，取出栈中最后一个标签头
                                $begin = array_pop($beginArray);
                                // 替换标签头部
                                $content = substr_replace($content, $begin["str"], $begin["pos"], $begin["len"]);
                            }
                        }
                        // 替换标签尾部
                        $content = substr_replace($content, $replace[1], $node["end"][1], strlen($node["end"][0]));
                        // 把标签头压入栈
                        $beginArray[] = ["pos" => $node["begin"][1], "len" => strlen($node["begin"][0]), "str" => $replace[0]];
                    }
                }
                while ($beginArray) {
                    $begin = array_pop($beginArray);
                    // 替换标签头部
                    $content = substr_replace($content, $begin["str"], $begin["pos"], $begin["len"]);
                }
            }
        }
        // 自闭合标签
        if (!empty($tags[0])) {
            $regex   = $this->getRegex(array_keys($tags[0]), 0);
            $content = preg_replace_callback($regex, function ($matches) use (&$tags, &$lib) {
                // 对应的标签名
                $name  = $tags[0][strtolower($matches[1])];
                $alias = $lib . $name != $matches[1] ? ($lib ? strstr($matches[1], $lib) : $matches[1]) : "";
                // 解析标签属性
                $attrs  = $this->parseAttr($matches[0], $name, $alias);
                $method = "tag" . $name;
                return $this->$method($attrs, "");
            }, $content);
        }
        return;
    }

$taglib->getRegex()

标签的正则表达式

private function getRegex($tags, $close)
    {
        $begin   = $this->tpl->config("taglib_begin");
        $end     = $this->tpl->config("taglib_end");
        $single  = strlen(ltrim($begin, "\")) == 1 && strlen(ltrim($end, "\")) == 1 ? true : false;
        $tagName = is_array($tags) ? implode("|", $tags) : $tags;
        if ($single) {
            if ($close) {
                // 如果是闭合标签
                $regex = $begin . "(?:(" . $tagName . ")(?>[^" . $end . "]*)|/(" . $tagName . "))" . $end;
            } else {
                $regex = $begin . "(" . $tagName . ")(?>[^" . $end . "]*)" . $end;
            }
        } else {
            if ($close) {
                // 如果是闭合标签
                $regex = $begin . "(?:(" . $tagName . ")(?>(?:(?!" . $end . ").)*)|/(" . $tagName . "))" . $end;
            } else {
                $regex = $begin . "(" . $tagName . ")(?>(?:(?!" . $end . ").)*)" . $end;
            }
        }
        return "/" . $regex . "/is";
    }

$taglib->parseAttr()

使用正则表达式分析标签属性

public function parseAttr($str, $name, $alias = "")
    {
        $regex  = "/s+(?>(?P<name>[w-]+)s*)=(?>s*)([""])(?P<value>(?:(?!\2).)*)\2/is";
        $result = [];
        if (preg_match_all($regex, $str, $matches)) {
            foreach ($matches["name"] as $key => $val) {
                $result[$val] = $matches["value"][$key];
            }
            if (!isset($this->tags[$name])) {
                // 检测是否存在别名定义
                foreach ($this->tags as $key => $val) {
                    if (isset($val["alias"])) {
                        $array = (array) $val["alias"];
                        if (in_array($name, explode(",", $array[0]))) {
                            $tag           = $val;
                            $type          = !empty($array[1]) ? $array[1] : "type";
                            $result[$type] = $name;
                            break;
                        }
                    }
                }
            } else {
                $tag = $this->tags[$name];
                // 设置了标签别名
                if (!empty($alias) && isset($tag["alias"])) {
                    $type          = !empty($tag["alias"][1]) ? $tag["alias"][1] : "type";
                    $result[$type] = $alias;
                }
            }
            if (!empty($tag["must"])) {
                $must = explode(",", $tag["must"]);
                foreach ($must as $name) {
                    if (!isset($result[$name])) {
                        throw new Exception("tag attr must:" . $name);
                    }
                }
            }
        } else {
            // 允许直接使用表达式的标签
            if (!empty($this->tags[$name]["expression"])) {
                static $_taglibs;
                if (!isset($_taglibs[$name])) {
                    $_taglibs[$name][0] = strlen(ltrim($this->tpl->config("taglib_begin"), "\") . $name);
                    $_taglibs[$name][1] = strlen(ltrim($this->tpl->config("taglib_end"), "\"));
                }
                $result["expression"] = substr($str, $_taglibs[$name][0], -$_taglibs[$name][1]);
                // 清除自闭合标签尾部/
                $result["expression"] = rtrim($result["expression"], "/");
                $result["expression"] = trim($result["expression"]);
            } elseif (empty($this->tags[$name]) || !empty($this->tags[$name]["attr"])) {
                throw new Exception("tag error:" . $name);
            }
        }
        return $result;
    }

2-2 标签库的其他辅助解析函数

$taglib->getTags()

获取标签定义

public function getTags()
    {
        return $this->tags;
    }

TP5在 emplate abligCx.php中，定义了内置标签的解析方式

每个标签的解析实现为相应标签的tagxx()方法

$cx->tagPhp()

$cx->tagVolist()

$cx->tagForeach()

$cx->tagIf()

$cx->tagElseif()

$cx->tagElse()

$cx->tagSwitch()

$cx->tagCase()

$cx->tagDefault()

$cx->tagCompare()

$cx->tagRange()

$cx->tagPresent()

$cx->tagNotPresent()

$cx->tagEmpty()

$cx->tagNotempty()

$cx->tagDefined()

$cx->tagNotdefined()

$cx->tagLoad()

$cx->tagAssign()

$cx->tagDefine()

$cx->tagFor()

$cx->tagUrl()

$cx->tagFunction()