From 92d18cf32edab81ac77f547cfa718cf28a573c92 Mon Sep 17 00:00:00 2001
From: Thomas Bruederli <thomas@roundcube.net>
Date: Fri, 04 Oct 2013 07:50:12 -0400
Subject: [PATCH] New option to disable the use of already established dsnw connections for subsequent reads

---
 program/lib/Roundcube/rcube_db.php |  243 +++++++++++++++++++++++++++++++++++-------------
 1 files changed, 175 insertions(+), 68 deletions(-)

diff --git a/program/lib/Roundcube/rcube_db.php b/program/lib/Roundcube/rcube_db.php
index 47ddc81..2861a91 100644
--- a/program/lib/Roundcube/rcube_db.php
+++ b/program/lib/Roundcube/rcube_db.php
@@ -32,6 +32,7 @@
     protected $db_connected = false;  // Already connected ?
     protected $db_mode;               // Connection mode
     protected $dbh;                   // Connection handle
+    protected $dbhs = array();
 
     protected $db_error     = false;
     protected $db_error_msg = '';
@@ -47,6 +48,7 @@
         'identifier_end'   => '"',
     );
 
+    const DEBUG_LINE_LENGTH = 4096;
 
     /**
      * Factory, returns driver-specific instance of the class
@@ -70,7 +72,7 @@
         $driver = isset($driver_map[$driver]) ? $driver_map[$driver] : $driver;
         $class  = "rcube_db_$driver";
 
-        if (!class_exists($class)) {
+        if (!$driver || !class_exists($class)) {
             rcube::raise_error(array('code' => 600, 'type' => 'db',
                 'line' => __LINE__, 'file' => __FILE__,
                 'message' => "Configuration error. Unsupported database driver: $driver"),
@@ -96,39 +98,35 @@
         $this->db_dsnw  = $db_dsnw;
         $this->db_dsnr  = $db_dsnr;
         $this->db_pconn = $pconn;
+        $this->db_dsnw_noread = rcube::get_instance()->config->get('db_dsnw_noread', false);
 
         $this->db_dsnw_array = self::parse_dsn($db_dsnw);
         $this->db_dsnr_array = self::parse_dsn($db_dsnr);
-
-        // Initialize driver class
-        $this->init();
-    }
-
-    /**
-     * Initialization of the object with driver specific code
-     */
-    protected function init()
-    {
-        // To be used by driver classes
     }
 
     /**
      * Connect to specific database
      *
-     * @param array $dsn DSN for DB connections
-     *
-     * @return PDO database handle
+     * @param array  $dsn  DSN for DB connections
+     * @param string $mode Connection mode (r|w)
      */
-    protected function dsn_connect($dsn)
+    protected function dsn_connect($dsn, $mode)
     {
         $this->db_error     = false;
         $this->db_error_msg = null;
+
+        // return existing handle
+        if ($this->dbhs[$mode]) {
+            $this->dbh = $this->dbhs[$mode];
+            $this->db_mode = $mode;
+            return $this->dbh;
+        }
 
         // Get database specific connection options
         $dsn_string  = $this->dsn_string($dsn);
         $dsn_options = $this->dsn_options($dsn);
 
-        if ($db_pconn) {
+        if ($this->db_pconn) {
             $dsn_options[PDO::ATTR_PERSISTENT] = true;
         }
 
@@ -157,9 +155,11 @@
             return null;
         }
 
+        $this->dbh          = $dbh;
+        $this->dbhs[$mode]  = $dbh;
+        $this->db_mode      = $mode;
+        $this->db_connected = true;
         $this->conn_configure($dsn, $dbh);
-
-        return $dbh;
     }
 
     /**
@@ -182,16 +182,6 @@
     }
 
     /**
-     * Driver-specific database character set setting
-     *
-     * @param string $charset Character set name
-     */
-    protected function set_charset($charset)
-    {
-        $this->query("SET NAMES 'utf8'");
-    }
-
-    /**
      * Connect to appropriate database depending on the operation
      *
      * @param string $mode Connection mode (r|w)
@@ -210,31 +200,21 @@
 
         // Already connected
         if ($this->db_connected) {
-            // connected to db with the same or "higher" mode
-            if ($this->db_mode == 'w' || $this->db_mode == $mode) {
+            // connected to db with the same or "higher" mode (if allowed)
+            if ($this->db_mode == $mode || $this->db_mode == 'w' && !$this->db_dsnw_noread) {
                 return;
             }
         }
 
         $dsn = ($mode == 'r') ? $this->db_dsnr_array : $this->db_dsnw_array;
-
-        $this->dbh          = $this->dsn_connect($dsn);
-        $this->db_connected = is_object($this->dbh);
+        $this->dsn_connect($dsn, $mode);
 
         // use write-master when read-only fails
-        if (!$this->db_connected && $mode == 'r') {
-            $mode = 'w';
-            $this->dbh          = $this->dsn_connect($this->db_dsnw_array);
-            $this->db_connected = is_object($this->dbh);
+        if (!$this->db_connected && $mode == 'r' && $this->is_replicated()) {
+            $this->dsn_connect($this->db_dsnw_array, 'w');
         }
 
-        if ($this->db_connected) {
-            $this->db_mode = $mode;
-            $this->set_charset('utf8');
-        }
-        else {
-            $this->conn_failure = true;
-        }
+        $this->conn_failure = !$this->db_connected;
     }
 
     /**
@@ -255,6 +235,11 @@
     protected function debug($query)
     {
         if ($this->options['debug_mode']) {
+            if (($len = strlen($query)) > self::DEBUG_LINE_LENGTH) {
+                $diff  = $len - self::DEBUG_LINE_LENGTH;
+                $query = substr($query, 0, self::DEBUG_LINE_LENGTH)
+                    . "... [truncated $diff bytes]";
+            }
             rcube::write_log('sql', '[' . (++$this->db_index) . '] ' . $query . ';');
         }
     }
@@ -362,8 +347,10 @@
      */
     protected function _query($query, $offset, $numrows, $params)
     {
+        $query = trim($query);
+
         // Read or write ?
-        $mode = preg_match('/^(select|show)/i', ltrim($query)) ? 'r' : 'w';
+        $mode = preg_match('/^(select|show|set)/i', $query) ? 'r' : 'w';
 
         $this->db_connect($mode);
 
@@ -400,21 +387,44 @@
 
         $this->debug($query);
 
-        $query = $this->dbh->query($query);
+        // destroy reference to previous result, required for SQLite driver (#1488874)
+        $this->last_result = null;
+        $this->db_error_msg = null;
 
-        if ($query === false) {
-            $error = $this->dbh->errorInfo();
+        // send query
+        $result = $this->dbh->query($query);
+
+        if ($result === false) {
+            $result = $this->handle_error($query);
+        }
+
+        $this->last_result = $result;
+
+        return $result;
+    }
+
+    /**
+     * Helper method to handle DB errors.
+     * This by default logs the error but could be overriden by a driver implementation
+     *
+     * @param string Query that triggered the error
+     * @return mixed Result to be stored and returned
+     */
+    protected function handle_error($query)
+    {
+        $error = $this->dbh->errorInfo();
+
+        if (empty($this->options['ignore_key_errors']) || $error[0] != '23000') {
             $this->db_error = true;
             $this->db_error_msg = sprintf('[%s] %s', $error[1], $error[2]);
 
             rcube::raise_error(array('code' => 500, 'type' => 'db',
                 'line' => __LINE__, 'file' => __FILE__,
-                'message' => $this->db_error_msg), true, false);
+                'message' => $this->db_error_msg . " (SQL Query: $query)"
+                ), true, false);
         }
 
-        $this->last_result = $query;
-
-        return $query;
+        return false;
     }
 
     /**
@@ -422,7 +432,7 @@
      *
      * @param mixed $result Optional query handle
      *
-     * @return int Number of rows or false on failure
+     * @return int Number of (matching) rows
      */
     public function affected_rows($result = null)
     {
@@ -431,6 +441,32 @@
         }
 
         return 0;
+    }
+
+    /**
+     * Get number of rows for a SQL query
+     * If no query handle is specified, the last query will be taken as reference
+     *
+     * @param mixed $result Optional query handle
+     * @return mixed   Number of rows or false on failure
+     * @deprecated This method shows very poor performance and should be avoided.
+     */
+    public function num_rows($result = null)
+    {
+        if ($result || ($result === null && ($result = $this->last_result))) {
+            // repeat query with SELECT COUNT(*) ...
+            if (preg_match('/^SELECT\s+(?:ALL\s+|DISTINCT\s+)?(?:.*?)\s+FROM\s+(.*)$/ims', $result->queryString, $m)) {
+                $query = $this->dbh->query('SELECT COUNT(*) FROM ' . $m[1], PDO::FETCH_NUM);
+                return $query ? intval($query->fetchColumn(0)) : false;
+            }
+            else {
+                $num = count($result->fetchAll());
+                $result->execute();  // re-execute query because there's no seek(0)
+                return $num;
+            }
+        }
+
+        return false;
     }
 
     /**
@@ -566,7 +602,7 @@
      * Formats input so it can be safely used in a query
      *
      * @param mixed  $input Value to quote
-     * @param string $type  Type of data
+     * @param string $type  Type of data (integer, bool, ident)
      *
      * @return string Quoted/converted string for use in query
      */
@@ -579,6 +615,10 @@
 
         if (is_null($input)) {
             return 'NULL';
+        }
+
+        if ($type == 'ident') {
+            return $this->quote_identifier($input);
         }
 
         // create DB handle if not available
@@ -599,6 +639,22 @@
     }
 
     /**
+     * Escapes a string so it can be safely used in a query
+     *
+     * @param string $str A string to escape
+     *
+     * @return string Escaped string for use in a query
+     */
+    public function escape($str)
+    {
+        if (is_null($str)) {
+            return 'NULL';
+        }
+
+        return substr($this->quote($str), 1, -1);
+    }
+
+    /**
      * Quotes a string so it can be safely used as a table or column name
      *
      * @param string $str Value to quote
@@ -610,6 +666,20 @@
     public function quoteIdentifier($str)
     {
         return $this->quote_identifier($str);
+    }
+
+    /**
+     * Escapes a string so it can be safely used in a query
+     *
+     * @param string $str A string to escape
+     *
+     * @return string Escaped string for use in a query
+     * @deprecated    Replaced by rcube_db::escape
+     * @see           rcube_db::escape
+     */
+    public function escapeSimple($str)
+    {
+        return $this->escape($str);
     }
 
     /**
@@ -630,24 +700,32 @@
             $name[] = $start . $elem . $end;
         }
 
-        return  implode($name, '.');
+        return implode($name, '.');
     }
 
     /**
      * Return SQL function for current time and date
      *
+     * @param int $interval Optional interval (in seconds) to add/subtract
+     *
      * @return string SQL function to use in query
      */
-    public function now()
+    public function now($interval = 0)
     {
-        return "now()";
+        if ($interval) {
+            $add = ' ' . ($interval > 0 ? '+' : '-') . ' INTERVAL ';
+            $add .= $interval > 0 ? intval($interval) : intval($interval) * -1;
+            $add .= ' SECOND';
+        }
+
+        return "now()" . $add;
     }
 
     /**
      * Return list of elements for use with SQL's IN clause
      *
      * @param array  $arr  Input array
-     * @param string $type Type of data
+     * @param string $type Type of data (integer, bool, ident)
      *
      * @return string Comma-separated list of quoted values for use in query
      */
@@ -723,12 +801,19 @@
     /**
      * Encodes non-UTF-8 characters in string/array/object (recursive)
      *
-     * @param mixed $input Data to fix
+     * @param mixed $input      Data to fix
+     * @param bool  $serialized Enable serialization
      *
      * @return mixed Properly UTF-8 encoded data
      */
-    public static function encode($input)
+    public static function encode($input, $serialized = false)
     {
+        // use Base64 encoding to workaround issues with invalid
+        // or null characters in serialized string (#1489142)
+        if ($serialized) {
+            return base64_encode(serialize($input));
+        }
+
         if (is_object($input)) {
             foreach (get_object_vars($input) as $idx => $value) {
                 $input->$idx = self::encode($value);
@@ -739,6 +824,7 @@
             foreach ($input as $idx => $value) {
                 $input[$idx] = self::encode($value);
             }
+
             return $input;
         }
 
@@ -748,12 +834,24 @@
     /**
      * Decodes encoded UTF-8 string/object/array (recursive)
      *
-     * @param mixed $input Input data
+     * @param mixed $input      Input data
+     * @param bool  $serialized Enable serialization
      *
      * @return mixed Decoded data
      */
-    public static function decode($input)
+    public static function decode($input, $serialized = false)
     {
+        // use Base64 encoding to workaround issues with invalid
+        // or null characters in serialized string (#1489142)
+        if ($serialized) {
+            // Keep backward compatybility where base64 wasn't used
+            if (strpos(substr($input, 0, 16), ':') !== false) {
+                return self::decode(@unserialize($input));
+            }
+
+            return @unserialize(base64_decode($input));
+        }
+
         if (is_object($input)) {
             foreach (get_object_vars($input) as $idx => $value) {
                 $input->$idx = self::decode($value);
@@ -781,17 +879,26 @@
     {
         $rcube = rcube::get_instance();
 
-        // return table name if configured
-        $config_key = 'db_table_'.$table;
-
-        if ($name = $rcube->config->get($config_key)) {
-            return $name;
+        // add prefix to the table name if configured
+        if ($prefix = $rcube->config->get('db_prefix')) {
+            return $prefix . $table;
         }
 
         return $table;
     }
 
     /**
+     * Set class option value
+     *
+     * @param string $name  Option name
+     * @param mixed  $value Option value
+     */
+    public function set_option($name, $value)
+    {
+        $this->options[$name] = $value;
+    }
+
+    /**
      * MDB2 DSN string parser
      *
      * @param string $sequence Secuence name

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