<?php

# PHP_SELF: 但前正在执行脚本的文件名，与document root相关
# QUERY_STRING: 查询(query)的字符串
$cachefile = "cache".$_SERVER['PHP_SELF']."?".$_SERVER['QUERY_STRING'];
                                                    #            ^
function start_caching()                            #            |
{                                                   #            |
    //Use the global $cachefile variable            #            |
    global $cachefile;                              #  -->---->--+

    //There is a random string to the end of the $_GET Query String to
    //prevent IE from caching the Ajax request. The below line removes the random portion
    //of the query so we can cache the page properly in php
    if(stripos($cachefile, "&rand=")==true)
        $cachefile = substr($cachefile,0,stripos($cachefile, "&rand="));

    if (file_exists($cachefile)) 
    {
        // the page has been cached from an earlier request
        // output the contents of the cache file
        include($cachefile); 
        // exit the script, so that the rest isnt executed
        exit;
    }
    else
        ob_start();
}

function get_application($dot_desktop_array,$submenu,$app_name)
{
    for($i = 0;$i<count($dot_desktop_array[$submenu]["apps"]);$i++)
    {
        if($dot_desktop_array[$submenu]["apps"][$i]["Name"]==$app_name)
            return     $dot_desktop_array[$submenu]["apps"][$i];
    }
    return NULL;
}

function end_caching()
{
    //Use the global $cachefile variable
    global $cachefile;

    //Disable Caching on Description Page
    // open the cache file "cache/home.html" for writing
    $fp = fopen($cachefile, 'w');
    // save the contents of output buffer to the file
    fwrite($fp, ob_get_contents());
    // close the file
    fclose($fp);
    // Send the output to the browser
    ob_end_flush();
}

function get_submenu($dot_desktop_array,$submenu_name)
{
    # foreach 循环
    # $k: 表示数组的下标
    # $v: 表示k下标对应的数组值
    foreach ($dot_desktop_array as $k => $v) 
    {
        for($j = 0;$j<count($v["apps"]);$j++)
        {    
            $current_entry = $v["apps"][$j];

            # 如果当前的记录类型是目录，并且当前分类和给定名字一样，那么返回该对象
            if($current_entry["Type"]=="directory" && $current_entry["Category"] == $submenu_name)
                return $current_entry;
        }
    }
    return NULL;
}

function read_desktop_file()
{
    # 检查json.txt是否存在，并且json.txt文件长度不为0
    if(file_exists("json.txt") == true && filesize("json.txt") != 0)
    {
        # 打开并读取文件
        $handle = fopen("json.txt", "rb");
        $contents = fread($handle,filesize("json.txt"));
        fclose($handle);

        # 接受一个JSON格式的字符串并且把它转换为PHP变量，
        # 返回解析后的json对象
        return json_decode($contents,true);
    }
    else
        return null;
}

?>