<?php
// File name:	lastmodf.inc.php
// Description:	PHP subroutines to calculate the last-modification date
// Date:	2004-11-26
// Author:	imacat <imacat@pristine.com.tw>
// Copyright:	Copyright (C) 2004-2007 Pristine Communications

// Set the include path
if (!defined("INCPATH_SET")) {
    require_once dirname(__FILE__) . "/incpath.inc.php";
}
// Referenced subroutines
require_once "monica/cgiemu.inc.php";
require_once "monica/getlang.inc.php";
require_once "monica/gettext.inc.php";
require_once "monica/lninfo.inc.php";
require_once "monica/requri.inc.php";
require_once "monica/sql.inc.php";
require_once "monica/sqlconst.inc.php";

// not_modified: Check if we should send "HTTP/1.1 304 Not Modified"
function not_modified($tables, $files, $this_file)
{
    // HTTP/1.1 304 only works for GET or HEAD
    if (!in_array($_SERVER["REQUEST_METHOD"], array("GET", "HEAD"))) {
        return false;
    }
    
    // Find the last-modified time
    find_last_modified($tables, $files, $this_file);
    // If-Modified-Since not supplied.  The client had not cached yet.
    if (!array_key_exists("HTTP_IF_MODIFIED_SINCE", $_SERVER)) {
        return false;
    }
    // Malformed If-Modified-Since value
    $cachemodf = strtotime($_SERVER["HTTP_IF_MODIFIED_SINCE"]);
    if ($cachemodf == -1) {
        return false;
    }
    // We are newer than the cache
    if ($GLOBALS["LAST_MODIFIED"] > $cachemodf) {
        return false;
    }
    // Yes, use the cache
    return true;
    return;
}

// find_last_modified: Find the last-modified time
function find_last_modified($tables, $files, $this_file)
{
    // Checked before
    if (array_key_exists("LAST_MODIFIED", $GLOBALS)) {
        return;
    }
    
    // Remove duplicates
    $tables = array_values(array_unique($tables));
    $files = array_values(array_unique($files));
    
    // Start with EPOCH 1970-01-01 00:00:00
    $GLOBALS["LAST_MODIFIED"] = 0;
    global $LAST_MODIFIED;
    
    // Check myself
    updmtime_file($this_file);
    // Check mtime from the included modules and gettext MO files
    check_inc();
    // Check the supplied data files
    foreach ($files as $file) {
        if (file_exists($file)) {
            updmtime_file($file);
        }
    }
    // Check the supplied data tables
    updmtime_tables($tables);
}

// check_inc: Check mtime from the included modules and gettext MO files
function check_inc()
{
    // Check the included modules
    foreach (get_included_files() as $file) {
        updmtime_file($file);
    }
    
    // Check the header and footer
    $incdir = DOC_ROOT . "/admin/include";
    $files = array();
    $files[] = $incdir . "/header." . getlang(LN_FILENAME) . ".html";
    $files[] = $incdir . "/footer." . getlang(LN_FILENAME) . ".html";
    $files[] = $incdir . "/header.html";
    $files[] = $incdir . "/footer.html";
    foreach ($files as $file) {
        if (file_exists($file)) {
            updmtime_file($file);
        }
    }
    
    // Check the gettext mo files
    if (defined("PACKAGE") && is_dir(LOCALEDIR)) {
        $dh = opendir(LOCALEDIR);
        while (($ent = readdir($dh)) !== false) {
            $file = LOCALEDIR . "/$ent/LC_MESSAGES/" . PACKAGE . ".mo";
            if (file_exists($file)) {
                updmtime_file($file);
            }
        }
        closedir($dh);
    }
    $dh = opendir(COMMONLOCALEDIR);
    while (($ent = readdir($dh)) !== false) {
        $file = COMMONLOCALEDIR . "/$ent/LC_MESSAGES/" . COMMONDOMAIN . ".mo";
        if (file_exists($file)) {
            updmtime_file($file);
        }
    }
    closedir($dh);
    return;
}

// updmtime_tables: Update the $LAST_MODIFIED with the mtime of tables
function updmtime_tables($tables)
{
    // Only work when using database
    if ($GLOBALS["SQL_DBTYPE"] == SQL_NONE) {
        return;
    }
    $lastupd = sql_lastupd($tables);
    if (is_null($lastupd)) {
        return;
    }
    if (!is_numeric($lastupd)) {
        $lastupd = preg_replace("/\.\d+$/", "", $lastupd);
        $lastupd = strtotime($lastupd);
    }
    settype($lastupd, "integer");
    if ($GLOBALS["LAST_MODIFIED"] < $lastupd) {
        $GLOBALS["LAST_MODIFIED"] = $lastupd;
    }
    return;
}

// updmtime_file: Update the $LAST_MODIFIED with the mtime of a file
function updmtime_file($file)
{
    $stat = stat($file);
    if ($GLOBALS["LAST_MODIFIED"] < $stat[9]) {
        $GLOBALS["LAST_MODIFIED"] = $stat[9];
    }
    return;
}

?>