lib/DbaDatabase.php

   1 <?php // rcs_id('$Id$');
   2
   3 require_once('lib/ErrorManager.php');
   4
   5 if (isWindows())
   6     define('DBA_DATABASE_DEFAULT_TIMEOUT', 60);
   7 else
   8     define('DBA_DATABASE_DEFAULT_TIMEOUT', 5);
   9
  10 class DbaDatabase
  11 {
  12     function DbaDatabase($filename, $mode = false, $handler = 'gdbm') {
  13         $this->_file = $filename;
  14         $this->_handler = $handler;
  15         $this->_timeout = DBA_DATABASE_DEFAULT_TIMEOUT;
  16         $this->_dbh = false;
  17         if (function_exists("dba_handlers")) { // since php-4.3.0
  18             if (!in_array($handler, dba_handlers()))
  19                 $this->_error(
  20                     sprintf(
  21                             _("The DBA handler %s is unsupported!")."\n".
  22                             _("Supported handlers are: %s"),
  23                             $handler, join(",",dba_handlers())));
  24         }
  25         $this->readonly = false;
  26         if ($mode)
  27             $this->open($mode);
  28     }
  29
  30     function set_timeout($timeout) {
  31         $this->_timeout = $timeout;
  32     }
  33
  34     function open($mode = 'w') {
  35         if ($this->_dbh)
  36             return;             // already open.
  37
  38         $watchdog = $this->_timeout;
  39
  40         global $ErrorManager;
  41         $this->_dba_open_error = false;
  42         $ErrorManager->pushErrorHandler(new WikiMethodCb($this, '_dba_open_error_handler'));
  43
  44         // oops, you don't have DBA support.
  45         if (!function_exists("dba_open")) {
  46             echo "You don't seem to have DBA support compiled into PHP.";
  47         }
  48
  49         if (READONLY) {
  50             $mode = 'r';
  51         }
  52
  53         if ((strlen($mode) == 1)) {
  54             // PHP 4.3.x Windows lock bug workaround: http://bugs.php.net/bug.php?id=23975
  55             if (isWindows()) {
  56                 $mode .= "-";                   // suppress locking, or
  57             } elseif ($this->_handler != 'gdbm') {      // gdbm does it internally
  58                 $mode .= "d";                   // else use internal locking
  59             }
  60         }
  61         while (($dbh = dba_open($this->_file, $mode, $this->_handler)) < 1) {
  62             if ($watchdog <= 0)
  63                 break;
  64             // "c" failed, try "w" instead.
  65             if ($mode == "w"
  66                 and file_exists($this->_file)
  67                 and (isWindows() or !is_writable($this->_file)))
  68             {
  69                 // try to continue with read-only
  70                 if (!defined("READONLY"))
  71                     define("READONLY", true);
  72                 $GLOBALS['request']->_dbi->readonly = true;
  73                 $this->readonly = true;
  74                 $mode = "r";
  75             }
  76             if (substr($mode,0,1) == "c" and file_exists($this->_file) and !READONLY)
  77                 $mode = "w";
  78             // conflict: wait some random time to unlock (as with ethernet)
  79             $secs = 0.5 + ((double)rand(1,32767)/32767);
  80             sleep($secs);
  81             $watchdog -= $secs;
  82             if (strlen($mode) == 2) $mode = substr($mode,0,-1);
  83         }
  84         $ErrorManager->popErrorHandler();
  85
  86         if (!$dbh) {
  87             if ( ($error = $this->_dba_open_error) ) {
  88                 $error->errno = E_USER_ERROR;
  89                 $error->errstr .= "\nfile: " . $this->_file
  90                                .  "\nmode: " . $mode
  91                                .  "\nhandler: " . $this->_handler;
  92                 // try to continue with read-only
  93                 if (!defined("READONLY"))
  94                     define("READONLY", true);
  95                 $GLOBALS['request']->_dbi->readonly = true;
  96                 $this->readonly = true;
  97                 if (!file_exists($this->_file)) {
  98                     $ErrorManager->handleError($error);
  99                     flush();
 100                 }
 101             }
 102             else {
 103                 trigger_error("dba_open failed", E_USER_ERROR);
 104             }
 105         }
 106         $this->_dbh = $dbh;
 107         return !empty($dbh);
 108     }
 109
 110     function close() {
 111         if ($this->_dbh)
 112             dba_close($this->_dbh);
 113         $this->_dbh = false;
 114     }
 115
 116     function exists($key) {
 117         return dba_exists($key, $this->_dbh);
 118     }
 119
 120     function fetch($key) {
 121         $val = dba_fetch($key, $this->_dbh);
 122         if ($val === false)
 123             return $this->_error("fetch($key)");
 124         return $val;
 125     }
 126
 127     function insert($key, $val) {
 128         if (!dba_insert($key, $val, $this->_dbh))
 129             return $this->_error("insert($key)");
 130     }
 131
 132     function replace($key, $val) {
 133         if (!dba_replace($key, $val, $this->_dbh))
 134             return $this->_error("replace($key)");
 135     }
 136
 137
 138     function firstkey() {
 139         return dba_firstkey($this->_dbh);
 140     }
 141
 142     function nextkey() {
 143         return dba_nextkey($this->_dbh);
 144     }
 145
 146     function delete($key) {
 147         if ($this->readonly) return;
 148         if (!dba_delete($key, $this->_dbh))
 149             return $this->_error("delete($key)");
 150     }
 151
 152     function get($key) {
 153         return dba_fetch($key, $this->_dbh);
 154     }
 155
 156     function set($key, $val) {
 157         $dbh = &$this->_dbh;
 158         if ($this->readonly) return;
 159         if (dba_exists($key, $dbh)) {
 160             if ($val !== false) {
 161                 if (!dba_replace($key, $val, $dbh))
 162                     return $this->_error("store[replace]($key)");
 163             }
 164             else {
 165                 if (!dba_delete($key, $dbh))
 166                     return $this->_error("store[delete]($key)");
 167             }
 168         }
 169         else {
 170             if (!dba_insert($key, $val, $dbh))
 171                 return $this->_error("store[insert]($key)");
 172         }
 173     }
 174
 175     function sync() {
 176         if (!dba_sync($this->_dbh))
 177             return $this->_error("sync()");
 178     }
 179
 180     function optimize() {
 181         if (!dba_optimize($this->_dbh))
 182             return $this->_error("optimize()");
 183         return 1;
 184     }
 185
 186     function _error($mes) {
 187         //trigger_error("DbaDatabase: $mes", E_USER_WARNING);
 188         //return false;
 189         trigger_error("$this->_file: dba error: $mes", E_USER_ERROR);
 190     }
 191
 192     function _dump() {
 193         $dbh = &$this->_dbh;
 194         for ($key = $this->firstkey($dbh); $key; $key = $this->nextkey($dbh))
 195             printf("%10s: %s\n", $key, $this->fetch($key));
 196     }
 197
 198     function _dba_open_error_handler($error) {
 199         $this->_dba_open_error = $error;
 200         return true;
 201     }
 202 }
 203
 204 // Local Variables:
 205 // mode: php
 206 // tab-width: 8
 207 // c-basic-offset: 4
 208 // c-hanging-comment-ender-p: nil
 209 // indent-tabs-mode: nil
 210 // End:
 211 ?>