polyfony-inc/polyfony

<?php

namespace Polyfony;

class Cache {

    // number of cache hits
    private static int $hits_count = 0;
    // number of cache misses
    private static int $misses_count = 0;
    // elapsed time putting into the cache
    private static float $cache_in_time = 0;
    // elapsed time retrieving from cache
    private static float $cache_out_time = 0;

    public static function getStatistics() :array {
        return [
            'hits_count'    =>self::$hits_count,
            'misses_count'    =>self::$misses_count,
            'cache_in_time'    =>self::$cache_in_time,
            'cache_out_time'=>self::$cache_out_time,
        ];
    }

    private static function path($variable) :string {

        // secure the variable name
        $variable = \Polyfony\Format::fsSafe($variable);
        // build the path
        return Config::get('cache', 'path') . $variable;

    }

    public static function has(string $variable) :bool {

        // set the variable path
        $path = self::path($variable);
        // if the file exists 
        if(file_exists($path)) {
            // if it expired
            if(filemtime($path) < time()) {
                // the file expired, remove it
                unlink($path);
                // we don't have that element
                return false;
            }
            // the cache file has not expired yet
            else {
                // we do have the file
                return true;
            }
        }
        // file doesn't even exist
        else {
            // we don't have that element
            return false;
        }

    }
    

    public static function put(
        string $variable, 
        $value=null, 
        $overwrite=false, 
        $lifetime=false
    ) :bool {
    
        // already exists and no overwrite
        if(self::has($variable) && !$overwrite) {
            // throw an exception
            Throw new \Polyfony\Exception("{$variable} already exists in the store.");
        }
        // only if the profiler is enabled
        if(Config::get('profiler','enable')) {
            // feed the statistics
            self::$misses_count++;
            $start = microtime(true);
        }
        // store it
        file_put_contents(self::path($variable), msgpack_pack($value));
        // compute the expiration time or set to a year by default
        $lifetime = $lifetime ? time() + $lifetime : time() + 365 * 24 * 3600;
        // alter the modification time
        touch(self::path($variable), $lifetime);
        // only if the profiler is enabled
        if(Config::get('profiler','enable')) {
            self::$cache_in_time += microtime(true) - $start;
        }
        // return status
        return self::has($variable);
        
    }
    

    public static function get(string $variable) {

        // doesn't exist in the store
        if(!self::has($variable)) {
            // throw an exception
            Throw new \Polyfony\Exception("{$variable} does not exist in the store.");
        }
        // only if the profiler is enabled
        if(Config::get('profiler','enable')) {
            // feed the statistics
            self::$hits_count++;
            $start = microtime(true);
        }
        // get it, unpack it 
        $cache_item = msgpack_unpack(file_get_contents(self::path($variable)));
        // only if the profiler is enabled
        if(Config::get('profiler','enable')) {
            self::$cache_out_time += microtime(true) - $start;
        }
        return $cache_item;
        
    }
    
    
    public static function remove(string $variable) :bool {
        
        // doesn't exist in the store
        if(!self::has($variable)) {
            // return false
            return(false);    
        }
        // remove it
        unlink(self::path($variable));
        // return it    
        return !self::has($variable);
        
    }
    
}    

?>