Merge branch 'develop' of git://github.com/EllisLab/CodeIgniter into develop

Conflicts:
	user_guide_src/source/changelog.rst

12 files changed, 513 insertions, 108 deletions

diff --git a/user_guide_src/source/libraries/email.rst b/user_guide_src/source/libraries/email.rst
index c5fa68004..da3bf2616 100644
--- a/user_guide_src/source/libraries/email.rst
+++ b/user_guide_src/source/libraries/email.rst
@@ -97,7 +97,7 @@ Preference          Default Value          Options                      Descript
 **mailtype**        text                   text or html                 Type of mail. If you send HTML email you must send it as a complete web
                                                                         page. Make sure you don't have any relative links or relative image
                                                                         paths otherwise they will not work.
-**charset**         utf-8                                               Character set (utf-8, iso-8859-1, etc.).
+**charset**         ``$config['charset']``                              Character set (utf-8, iso-8859-1, etc.).
 **validate**        FALSE                  TRUE or FALSE (boolean)      Whether to validate the email address.
 **priority**        3                      1, 2, 3, 4, 5                Email Priority. 1 = highest. 5 = lowest. 3 = normal.
 **crlf**            \\n                    "\\r\\n" or "\\n" or "\\r"   Newline character. (Use "\\r\\n" to comply with RFC 822).
@@ -117,6 +117,13 @@ Sets the email address and name of the person sending the email::
 
 	$this->email->from('you@example.com', 'Your Name');
 
+You can also set a Return-Path, to help redirect undelivered mail::
+
+	$this->email->from('you@example.com', 'Your Name', 'returned_emails@example.com');
+	
+.. note:: Return-Path can't be used if you've configured
+	'smtp' as your protocol.
+
 $this->email->reply_to()
 -------------------------
 
@@ -226,6 +233,14 @@ success or failure, enabling it to be used conditionally::
 	    // Generate error
 	}
 
+This function will automatically clear all parameters if the request was
+successful. To stop this behaviour pass FALSE::
+
+ 	if ($this->email->send(FALSE))
+ 	{
+ 		// Parameters won't be cleared
+ 	}
+
 $this->email->attach()
 ----------------------
 
diff --git a/user_guide_src/source/libraries/file_uploading.rst b/user_guide_src/source/libraries/file_uploading.rst
index 65cd5c722..1698dcbb9 100644
--- a/user_guide_src/source/libraries/file_uploading.rst
+++ b/user_guide_src/source/libraries/file_uploading.rst
@@ -197,6 +197,7 @@ Preference                   Default Value     Options                 Descripti
                                                                        Separate multiple types with a pipe.
 **file_name**                None              Desired file name       If set CodeIgniter will rename the uploaded file to this name. The
                                                                        extension provided in the file name must also be an allowed file type.
+                                                                       If no extension is provided in the original file_name will be used.
 **overwrite**                FALSE             TRUE/FALSE (boolean)    If set to true, if a file with the same name as the one you are
                                                                        uploading exists, it will be overwritten. If set to false, a number will
                                                                        be appended to the filename if another with the same name exists.
diff --git a/user_guide_src/source/libraries/form_validation.rst b/user_guide_src/source/libraries/form_validation.rst
index 3bcad7ba6..6c6743d06 100644
--- a/user_guide_src/source/libraries/form_validation.rst
+++ b/user_guide_src/source/libraries/form_validation.rst
@@ -399,7 +399,7 @@ The validation system supports callbacks to your own validation
 functions. This permits you to extend the validation class to meet your
 needs. For example, if you need to run a database query to see if the
 user is choosing a unique username, you can create a callback function
-that does that. Let's create a example of this.
+that does that. Let's create an example of this.
 
 In your controller, change the "username" rule to this::
 
@@ -488,6 +488,17 @@ the name of the function::
 
 	$this->form_validation->set_message('username_check')
 
+If you are using an error message that can accept two $s in your error string,
+such as:
+::
+
+	$this->form_validation->set_message('min_length', 'The $s field must contain at least $s characters.');
+
+Then you can also use %1$s and %2$s:
+::
+
+	$this->form_validation->set_message('min_length', 'This field must contain at least %2$s characters.');
+
 You can also override any error message found in the language file. For
 example, to change the message for the "required" rule you will do this::
 
@@ -861,8 +872,10 @@ Rule                      Parameter  Description
 ========================= ========== ============================================================================================= =======================
 **required**              No         Returns FALSE if the form element is empty.                                                                          
 **matches**               Yes        Returns FALSE if the form element does not match the one in the parameter.                    matches[form_item]     
-**is_unique**             Yes        Returns FALSE if the form element is not unique to the                                        is_unique[table.field] 
-                                     table and field name in the parameter. is_unique[table.field]                                                        
+**differs**               Yes        Returns FALSE if the form element does not differ from the one in the parameter.              differs[form_item]     
+**is_unique**             Yes        Returns FALSE if the form element is not unique to the table and field name in the            is_unique[table.field] 
+                                     parameter. Note: This rule requires :doc:`Query Builder <../database/query_builder>` to be                             
+                                     enabled in order to work.
 **max_length**            Yes        Returns FALSE if the form element is longer then the parameter value.                         max_length[12]         
 **exact_length**          Yes        Returns FALSE if the form element is not exactly the parameter value.                         exact_length[8]        
 **greater_than**          Yes        Returns FALSE if the form element is less than or equal to the parameter value or not         greater_than[8]
@@ -884,7 +897,6 @@ Rule                      Parameter  Description
                                      0, 1, 2, 3, etc.
 **is_natural_no_zero**    No         Returns FALSE if the form element contains anything other than a natural
                                      number, but not zero: 1, 2, 3, etc.
-**is_unique**             Yes        Returns FALSE if the form element is not unique in a database table.                          is_unique[table.field] 
 **valid_email**           No         Returns FALSE if the form element does not contain a valid email address.
 **valid_emails**          No         Returns FALSE if any value provided in a comma separated list is not a valid email.
 **valid_ip**              No         Returns FALSE if the supplied IP is not valid.
diff --git a/user_guide_src/source/libraries/image_lib.rst b/user_guide_src/source/libraries/image_lib.rst
index ed6575c62..dcdccbd92 100644
--- a/user_guide_src/source/libraries/image_lib.rst
+++ b/user_guide_src/source/libraries/image_lib.rst
@@ -91,9 +91,9 @@ error upon failure, like this::
 	    echo $this->image_lib->display_errors();
 	}
 
-Note: You can optionally specify the HTML formatting to be applied to
-the errors, by submitting the opening/closing tags in the function, like
-this::
+.. note:: You can optionally specify the HTML formatting to be applied to
+	the errors, by submitting the opening/closing tags in the function,
+	like this::
 
 	$this->image_lib->display_errors('<p>', '</p>');
 
@@ -225,8 +225,7 @@ pixels) specifying where to crop, like this::
 	$config['y_axis'] = '40';
 
 All preferences listed in the table above are available for this
-function except these: rotation_angle, width, height, create_thumb,
-new_image.
+function except these: rotation_angle, create_thumb, new_image.
 
 Here's an example showing how you might crop an image::
 
@@ -243,11 +242,11 @@ Here's an example showing how you might crop an image::
 	    echo $this->image_lib->display_errors();
 	}
 
-Note: Without a visual interface it is difficult to crop images, so this
-function is not very useful unless you intend to build such an
-interface. That's exactly what we did using for the photo gallery module
-in ExpressionEngine, the CMS we develop. We added a JavaScript UI that
-lets the cropping area be selected.
+.. note:: Without a visual interface it is difficult to crop images, so this
+	function is not very useful unless you intend to build such an
+	interface. That's exactly what we did using for the photo gallery module
+	in ExpressionEngine, the CMS we develop. We added a JavaScript UI that
+	lets the cropping area be selected.
 
 $this->image_lib->rotate()
 ===========================
@@ -338,8 +337,8 @@ The above example will use a 16 pixel True Type font to create the text
 bottom/center of the image, 20 pixels from the bottom of the image.
 
 .. note:: In order for the image class to be allowed to do any
-	processing, the image file must have "write" file permissions. For
-	example, 777.
+	processing, the image file must have "write" file permissions
+	For example, 777.
 
 Watermarking Preferences
 ========================
diff --git a/user_guide_src/source/libraries/javascript.rst b/user_guide_src/source/libraries/javascript.rst
index d5e09c314..393d4e321 100644
--- a/user_guide_src/source/libraries/javascript.rst
+++ b/user_guide_src/source/libraries/javascript.rst
@@ -192,7 +192,7 @@ and triggered by a click using the jQuery library's click() event.
 	'width' => '50%',
 	'marginLeft' => 125
 	);
-	$this->jquery->click('#trigger', $this->jquery->animate('#note', $params, normal));
+	$this->jquery->click('#trigger', $this->jquery->animate('#note', $params, 'normal'));
 
 fadeIn() / fadeOut()
 --------------------
diff --git a/user_guide_src/source/libraries/loader.rst b/user_guide_src/source/libraries/loader.rst
index aadf9740a..615aba1c2 100644
--- a/user_guide_src/source/libraries/loader.rst
+++ b/user_guide_src/source/libraries/loader.rst
@@ -4,6 +4,7 @@ Loader Class
 
 Loader, as the name suggests, is used to load elements. These elements
 can be libraries (classes) :doc:`View files <../general/views>`,
+:doc:`Drivers <../general/drivers>`,
 :doc:`Helpers <../general/helpers>`,
 :doc:`Models <../general/models>`, or your own files.
 
@@ -74,6 +75,70 @@ Assigning a Library to a different object name
 
 If the third (optional) parameter is blank, the library will usually be
 assigned to an object with the same name as the library. For example, if
+the library is named Calendar, it will be assigned to a variable named
+$this->calendar.
+
+If you prefer to set your own class names you can pass its value to the
+third parameter::
+
+	$this->load->library('calendar', '', 'my_calendar');
+
+	// Calendar class is now accessed using:
+
+	$this->my_calendar
+
+Please take note, when multiple libraries are supplied in an array for
+the first parameter, this parameter is discarded.
+
+$this->load->driver('parent_name', $config, 'object name')
+===========================================================
+
+This function is used to load driver libraries. Where parent_name is the
+name of the parent class you want to load.
+
+As an example, if you would like to use sessions with CodeIgniter, the first
+step is to load the session driver within your controller::
+
+	$this->load->driver('session');
+
+Once loaded, the library will be ready for use, using
+$this->session->*some_function*().
+
+Driver files must be stored in a subdirectory within the main
+"libraries" folder, or within your personal application/libraries
+folder. The subdirectory must match the parent class name. Read the
+:doc:`Drivers <../general/drivers>` description for details.
+
+Additionally, multiple driver libraries can be loaded at the same time by
+passing an array of drivers to the load function.
+
+::
+
+	$this->load->driver(array('session', 'cache'));
+
+Setting options
+---------------
+
+The second (optional) parameter allows you to optionally pass
+configuration settings. You will typically pass these as an array::
+
+	$config = array (
+	                  'sess_driver' => 'cookie',
+	                  'sess_encrypt_cookie'  => true,
+	                  'encryption_key' => 'mysecretkey'
+	               );
+
+	$this->load->driver('session', $config);
+
+Config options can usually also be set via a config file. Each library
+is explained in detail in its own page, so please read the information
+regarding each one you would like to use.
+
+Assigning a Driver to a different object name
+----------------------------------------------
+
+If the third (optional) parameter is blank, the library will be assigned
+to an object with the same name as the parent class. For example, if
 the library is named Session, it will be assigned to a variable named
 $this->session.
 
@@ -86,8 +151,8 @@ third parameter::
 
 	$this->my_session
 
-Please take note, when multiple libraries are supplied in an array for
-the first parameter, this parameter is discarded.
+.. note:: Driver libraries may also be loaded with the library() method,
+	but it is faster to use driver()
 
 $this->load->view('file_name', $data, true/false)
 ==================================================
@@ -279,6 +344,6 @@ calling add_package_path().
 	$this->load->remove_package_path(APPPATH.'my_app');
 
 	// Again without the second parameter:
-	$this->load->add_package_path(APPPATH.'my_app', TRUE);
+	$this->load->add_package_path(APPPATH.'my_app');
 	$this->load->view('my_app_index'); // Loads
-	$this->load->view('welcome_message'); // Loads
\ No newline at end of file
+	$this->load->view('welcome_message'); // Loads
diff --git a/user_guide_src/source/libraries/migration.rst b/user_guide_src/source/libraries/migration.rst
index 5192f1f29..cb7d96a6d 100644
--- a/user_guide_src/source/libraries/migration.rst
+++ b/user_guide_src/source/libraries/migration.rst
@@ -2,4 +2,136 @@
 Migrations Class
 ################
 
-Coming soon.
\ No newline at end of file
+Migrations are a convenient way for you to alter your database in a 
+structured and organized manner. You could edit fragments of SQL by hand 
+but you would then be responsible for telling other developers that they 
+need to go and run them. You would also have to keep track of which changes 
+need to be run against the production machines next time you deploy.
+
+The database table **migration** tracks which migrations have already been 
+run so all you have to do is update your application files and 
+call **$this->migrate->current()** to work out which migrations should be run. 
+The current version is found in **config/migration.php**.
+
+******************
+Create a Migration
+******************
+
+.. note:: Each Migration is run in numerical order forward or backwards 
+	depending on the method taken. Use a prefix of 3 numbers followed by an 
+	underscore for the filename of your migration.
+	
+This will be the first migration for a new site which has a blog. All 
+migrations go in the folder **application/migrations/** and have names such 
+as: **001_add_blog.php**.::
+
+	defined('BASEPATH') OR exit('No direct script access allowed');
+
+	class Migration_Add_blog extends CI_Migration {
+
+		public function up()
+		{
+			$this->dbforge->add_field(array(
+				'blog_id' => array(
+					'type' => 'INT',
+					'constraint' => 5,
+					'unsigned' => TRUE,
+					'auto_increment' => TRUE
+				),
+				'blog_title' => array(
+					'type' => 'VARCHAR',
+					'constraint' => '100',
+				),
+				'blog_description' => array(
+					'type' => 'TEXT',
+					'null' => TRUE,
+				),
+			));
+			
+			$this->dbforge->create_table('blog');
+		}
+
+		public function down()
+		{
+			$this->dbforge->drop_table('blog');
+		}
+
+Then in **application/config/migration.php** set **$config['migration_version'] = 1;**.
+
+*************
+Usage Example
+*************
+
+In this example some simple code is placed in **application/controllers/migrate.php** 
+to update the schema.::
+
+	$this->load->library('migration');
+
+	if ( ! $this->migration->current())
+	{
+		show_error($this->migration->error_string());
+	}
+
+******************
+Function Reference
+******************
+
+There are five available methods for the Migration class:
+
+-  $this->migration->current();
+-  $this->migration->error_string();
+-  $this->migration->find_migrations();
+-  $this->migration->latest();
+-  $this->migration->version();
+
+$this->migration->current()
+============================
+
+The current migration is whatever is set for **$config['migration_version']** in 
+**application/config/migration.php**.
+
+$this->migration->error_string()
+=================================
+
+This returns a string of errors while performing a migration.
+
+$this->migration->find_migrations()
+====================================
+
+An array of migration filenames are returned that are found in the **migration_path** 
+property.
+
+$this->migration->latest()
+===========================
+
+This works much the same way as current() but instead of looking for 
+the **$config['migration_version']** the Migration class will use the very 
+newest migration found in the filesystem.
+
+$this->migration->version()
+============================
+
+Version can be used to roll back changes or step forwards programmatically to 
+specific versions. It works just like current but ignores **$config['migration_version']**.::
+
+	$this->load->library('migration');
+
+	$this->migration->version(5);
+
+*********************
+Migration Preferences
+*********************
+
+The following is a table of all the config options for migrations.
+
+========================== ====================== ============= =============================================
+Preference                 Default                Options       Description
+========================== ====================== ============= =============================================
+**migration_enabled**      FALSE                  TRUE / FALSE  Enable or disable migrations.
+**migration_path**         APPPATH.'migrations/'  None          The path to your migrations folder.
+**migration_version**      0                      None          The current version your database should use.
+**migration_table**        migrations             None          The table name for storing the shema
+                                                                version number.
+**migration_auto_latest**  FALSE                  TRUE / FALSE  Enable or disable automatically 
+                                                                running migrations.
+========================== ====================== ============= =============================================
diff --git a/user_guide_src/source/libraries/output.rst b/user_guide_src/source/libraries/output.rst
index 0472d14cf..82b1a56a5 100644
--- a/user_guide_src/source/libraries/output.rst
+++ b/user_guide_src/source/libraries/output.rst
@@ -105,6 +105,9 @@ Permits you to manually set a server status header. Example::
 `See here <http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html>`_ for
 a full list of headers.
 
+.. note:: This method is an alias for :doc:`Common function <../general/common_functions>`
+	``set_status_header()``.
+
 $this->output->enable_profiler();
 ==================================
 
diff --git a/user_guide_src/source/libraries/pagination.rst b/user_guide_src/source/libraries/pagination.rst
index 7d750bd23..d9d3f5092 100644
--- a/user_guide_src/source/libraries/pagination.rst
+++ b/user_guide_src/source/libraries/pagination.rst
@@ -80,8 +80,8 @@ The number of "digit" links you would like before and after the selected
 page number. For example, the number 2 will place two digits on either
 side, as in the example links at the very top of this page.
 
-$config['use_page_number'] = TRUE;
-==================================
+$config['use_page_numbers'] = TRUE;
+===================================
 
 By default, the URI segment will use the starting index for the items
 you are paginating. If you prefer to show the the actual page number,
diff --git a/user_guide_src/source/libraries/sessions.rst b/user_guide_src/source/libraries/sessions.rst
index 5400524a9..dd9e8cbb4 100644
--- a/user_guide_src/source/libraries/sessions.rst
+++ b/user_guide_src/source/libraries/sessions.rst
@@ -1,29 +1,19 @@
-#############
-Session Class
-#############
+##############
+Session Driver
+##############
 
 The Session class permits you maintain a user's "state" and track their
-activity while they browse your site. The Session class stores session
-information for each user as serialized (and optionally encrypted) data
-in a cookie. It can also store the session data in a database table for
-added security, as this permits the session ID in the user's cookie to
-be matched against the stored session ID. By default only the cookie is
-saved. If you choose to use the database option you'll need to create
-the session table as indicated below.
-
-.. note:: The Session class does **not** utilize native PHP sessions. It
-	generates its own session data, offering more flexibility for
-	developers.
-
-.. note:: Even if you are not using encrypted sessions, you must set
-	an :doc:`encryption key <./encryption>` in your config file which is used
-	to aid in preventing session data manipulation.
+activity while they browse your site. CodeIgniter offers two default
+session drivers: the classic `Cookie Driver`_, and the `Native Driver`_,
+which supports usage of the native PHP Session mechanism. In addition,
+you may create your own `Custom Drivers`_ to store session data however
+you wish, while still taking advantage of the features of the Session class.
 
 Initializing a Session
 ======================
 
 Sessions will typically run globally with each page load, so the session
-class must either be :doc:`initialized <../general/libraries>` in your
+class must either be :doc:`initialized <../general/drivers>` in your
 :doc:`controller <../general/controllers>` constructors, or it can be
 :doc:`auto-loaded <../general/autoloader>` by the system. For the most
 part the session class will run unattended in the background, so simply
@@ -31,22 +21,25 @@ initializing the class will cause it to read, create, and update
 sessions.
 
 To initialize the Session class manually in your controller constructor,
-use the $this->load->library function::
+use the $this->load->driver function::
 
-	$this->load->library('session');
+	$this->load->driver('session');
 
 Once loaded, the Sessions library object will be available using:
 $this->session
 
+.. note:: For backward compatibility, the Session class may stil be loaded
+	using the $this->load->library function, but converting your applications
+	to use $this->load->driver is strongly recommended.
+
 How do Sessions work?
 =====================
 
 When a page is loaded, the session class will check to see if valid
-session data exists in the user's session cookie. If sessions data does
-**not** exist (or if it has expired) a new session will be created and
-saved in the cookie. If a session does exist, its information will be
-updated and the cookie will be updated. With each update, the
-session_id will be regenerated.
+session data exists in the user's session. If sessions data does **not**
+exist (or if it has expired) a new session will be created and saved.
+If a session does exist, its information will be updated. With each update,
+the session_id will be regenerated.
 
 It's important for you to understand that once initialized, the Session
 class runs automatically. There is nothing you need to do to cause the
@@ -79,19 +72,12 @@ prototype::
 	     'last_activity' => timestamp
 	)
 
-If you have the encryption option enabled, the serialized array will be
-encrypted before being stored in the cookie, making the data highly
-secure and impervious to being read or altered by someone. More info
-regarding encryption can be :doc:`found here <encryption>`, although
-the Session class will take care of initializing and encrypting the data
-automatically.
-
-Note: Session cookies are only updated every five minutes by default to
-reduce processor load. If you repeatedly reload a page you'll notice
-that the "last activity" time only updates if five minutes or more has
-passed since the last time the cookie was written. This time is
-configurable by changing the $config['sess_time_to_update'] line in
-your system/config/config.php file.
+.. note:: Sessions are only updated every five minutes by default to
+	reduce processor load. If you repeatedly reload a page you'll notice
+	that the "last activity" time only updates if five minutes or more has
+	passed since the last time the cookie was written. This time is
+	configurable by changing the $config['sess_time_to_update'] line in
+	your system/config/config.php file.
 
 Retrieving Session Data
 =======================
@@ -106,7 +92,7 @@ fetch. For example, to fetch the session ID you will do this::
 
 	$session_id = $this->session->userdata('session_id');
 
-.. note:: The function returns FALSE (boolean) if the item you are
+.. note:: The function returns NULL if the item you are
 	trying to access does not exist.
 
 Adding Custom Session Data
@@ -117,7 +103,7 @@ to it and it will be stored in the user's cookie. Why would you want to
 do this? Here's one example:
 
 Let's say a particular user logs into your site. Once authenticated, you
-could add their username and email address to the session cookie, making
+could add their username and email address to the session, making
 that data globally available to you without having to run a database
 query when you need it.
 
@@ -144,11 +130,11 @@ supports this syntax.
 
 	$this->session->set_userdata('some_name', 'some_value');
 
+If you want to verify that a userdata value exists, call has_userdata().
 
-.. note:: Cookies can only hold 4KB of data, so be careful not to exceed
-	the capacity. The encryption process in particular produces a longer
-	data string than the original so keep careful track of how much data you
-	are storing.
+::
+
+	$this->session->has_userdata('some_name');
 
 Retrieving All Session Data
 ===========================
@@ -195,8 +181,8 @@ available for the next server request, and are then automatically
 cleared. These can be very useful, and are typically used for
 informational or status messages (for example: "record 2 deleted").
 
-Note: Flash variables are prefaced with "flash\_" so avoid this prefix
-in your own session names.
+.. note:: Flash variables are prefaced with "flash\_" so avoid this prefix
+	in your own session names.
 
 To add flashdata::
 
@@ -222,9 +208,162 @@ additional request, you can do so using the keep_flashdata() function.
 
 	$this->session->keep_flashdata('item');
 
+Tempdata
+========
+
+CodeIgniter also supports "tempdata", or session data with a specific
+expiration time. After the value expires, or the session expires or is
+deleted, the value is automatically removed.
+
+To add tempdata::
+
+	$expire = 300;	// Expire in 5 minutes
+
+	$this->session->set_tempdata('item', 'value', $expire);
+
+You can also pass an array to set_tempdata()::
+
+	$tempdata = array('newuser' => TRUE, 'message' => 'Thanks for joining!');
+
+	$this->session->set_tempdata($tempdata, '', $expire);
+
+.. note:: If the expiration is omitted or set to 0, the default expiration of
+	5 minutes will be used.
+
+To read a tempdata variable::
+
+	$this->session->tempdata('item');
+
+If you need to remove a tempdata value before it expires,
+use unset_tempdata()::
+
+	$this->session->unset_tempdata('item');
+
+Destroying a Session
+====================
+
+To clear the current session::
+
+	$this->session->sess_destroy();
+
+.. note:: This function should be the last one called, and even flash
+	variables will no longer be available. If you only want some items
+	destroyed and not all, use unset_userdata().
+
+Session Preferences
+===================
+
+You'll find the following Session related preferences in your
+application/config/config.php file:
+
+=========================== =============== =========================== ==========================================================================
+Preference                  Default         Options                     Description
+=========================== =============== =========================== ==========================================================================
+**sess_driver**             cookie          cookie/native/*custom*      The initial session driver to load.
+**sess_valid_drivers**      cookie, native  None                        Additional valid drivers which may be loaded.
+**sess_cookie_name**        ci_session      None                        The name you want the session cookie saved as (data for Cookie driver or
+                                                                        session ID for Native driver).
+**sess_expiration**         7200            None                        The number of seconds you would like the session to last. The default
+                                                                        value is 2 hours (7200 seconds). If you would like a non-expiring
+                                                                        session set the value to zero: 0
+**sess_expire_on_close**    FALSE           TRUE/FALSE (boolean)        Whether to cause the session to expire automatically when the browser
+                                                                        window is closed.
+**sess_encrypt_cookie**     FALSE           TRUE/FALSE (boolean)        Whether to encrypt the session data (Cookie driver only).
+**sess_use_database**       FALSE           TRUE/FALSE (boolean)        Whether to save the session data to a database. You must create the
+                                                                        table before enabling this option (Cookie driver only).
+**sess_table_name**         ci_sessions     Any valid SQL table name    The name of the session database table (Cookie driver only).
+**sess_time_to_update**     300             Time in seconds             This options controls how often the session class will regenerate itself
+                                                                        and create a new session id.
+**sess_match_ip**           FALSE           TRUE/FALSE (boolean)        Whether to match the user's IP address when reading the session data.
+                                                                        Note that some ISPs dynamically changes the IP, so if you want a
+                                                                        non-expiring session you will likely set this to FALSE.
+**sess_match_useragent**    TRUE            TRUE/FALSE (boolean)        Whether to match the User Agent when reading the session data.
+=========================== =============== =========================== ==========================================================================
+
+In addition to the values above, the cookie and native drivers apply the
+following configuration values shared by the :doc:`Input <input>` and
+:doc:`Security <security>` classes:
+
+=========================== =============== ==========================================================================
+Preference                  Default         Description
+=========================== =============== ==========================================================================
+**cookie_prefix**           ''              Set a cookie name prefix in order to avoid name collisions
+**cookie_domain**           ''              The domain for which the session is applicable
+**cookie_path**             /               The path to which the session is applicable
+=========================== =============== ==========================================================================
+
+Session Drivers
+===============
+
+By default, the `Cookie Driver`_ is loaded when a session is initialized.
+However, any valid driver may be selected with the $config['sess_driver']
+line in your config.php file.
+
+The session driver library comes with the cookie and native drivers
+installed, and `Custom Drivers`_ may also be installed by the user.
+
+Typically, only one driver will be used at a time, but CodeIgniter does
+support loading multiple drivers. If a specific valid driver is called, it
+will be automatically loaded. Or, an additional driver may be explicitly
+loaded by calling load_driver()::
+
+	$this->session->load_driver('native');
+
+The Session library keeps track of the most recently selected driver to call
+for driver methods. Normally, session class methods are called directly on
+the parent class, as illustrated above. However, any methods called through
+a specific driver will select that driver before invoking the parent method.
+
+So, alternation between multiple drivers can be achieved by specifying which
+driver to use for each call::
+
+	$this->session->native->set_userdata('foo', 'bar');
+
+	$this->session->cookie->userdata('foo');
+
+	$this->session->native->unset_userdata('foo');
+
+Notice in the previous example that the *native* userdata value 'foo'
+would be set to 'bar', which would NOT be returned by the call for
+the *cookie* userdata 'foo', nor would the *cookie* value be unset by
+the call to unset the *native* 'foo' value. The drivers maintain independent
+sets of values, regardless of key names.
+
+A specific driver may also be explicitly selected for use by pursuant
+methods with the select_driver() call::
+
+	$this->session->select_driver('native');
+
+	$this->session->userdata('item');	// Uses the native driver
+
+Cookie Driver
+-------------
+
+The Cookie driver stores session information for each user as serialized
+(and optionally encrypted) data in a cookie. It can also store the session
+data in a database table for added security, as this permits the session ID
+in the user's cookie to be matched against the stored session ID. By default
+only the cookie is saved. If you choose to use the database option you'll
+need to create the session table as indicated below.
+
+If you have the encryption option enabled, the serialized array will be
+encrypted before being stored in the cookie, making the data highly
+secure and impervious to being read or altered by someone. More info
+regarding encryption can be :doc:`found here <encryption>`, although
+the Session class will take care of initializing and encrypting the data
+automatically.
+
+.. note:: Even if you are not using encrypted sessions, you must set
+	an :doc:`encryption key <./encryption>` in your config file which is used
+	to aid in preventing session data manipulation.
+
+.. note:: Cookies can only hold 4KB of data, so be careful not to exceed
+	the capacity. The encryption process in particular produces a longer
+	data string than the original so keep careful track of how much data you
+	are storing.
 
 Saving Session Data to a Database
-=================================
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 While the session data array stored in the user's cookie contains a
 Session ID, unless you store session data in a database there is no way
@@ -267,44 +406,83 @@ session class::
 
 		$config['sess_table_name'] = 'ci_sessions';
 
-.. note:: The Session class has built-in garbage collection which clears
+.. note:: The Cookie driver has built-in garbage collection which clears
 	out expired sessions so you do not need to write your own routine to do
 	it.
 
-Destroying a Session
-====================
+Native Driver
+-------------
 
-To clear the current session::
+The Native driver relies on native PHP sessions to store data in the
+$_SESSION superglobal array. All stored values continue to be available
+through $_SESSION, but flash- and temp- data items carry special prefixes.
 
-	$this->session->sess_destroy();
+Custom Drivers
+--------------
 
-.. note:: This function should be the last one called, and even flash
-	variables will no longer be available. If you only want some items
-	destroyed and not all, use unset_userdata().
+You may also :doc:`create your own <../general/creating_drivers>` custom
+session drivers. A session driver basically manages an array of name/value
+pairs with some sort of storage mechanism.
 
-Session Preferences
-===================
+To make a new driver, extend CI_Session_driver. Overload the initialize()
+method and read or create session data. Then implement a save handler to
+write changed data to storage (sess_save), a destroy handler to remove
+deleted data (sess_destroy), a regenerate handler to make a new session ID
+(sess_regenerate), and an access handler to expose the data (get_userdata).
+Your initial class might look like::
 
-You'll find the following Session related preferences in your
-application/config/config.php file:
+	class CI_Session_custom extends CI_Session_driver {
+		protected function initialize()
+		{
+			// Read existing session data or create a new one
+		}
+
+		public function sess_save()
+		{
+			// Save current data to storage
+		}
+
+		public function sess_destroy()
+		{
+			// Destroy the current session and clean up storage
+		}
+
+		public function sess_regenerate()
+		{
+			// Create new session ID
+		}
+
+		public function &get_userdata()
+		{
+			// Return a reference to your userdata array
+		}
+	}
+
+Notice that get_userdata() returns a reference so the parent library is
+accessing the same array the driver object is using. This saves memory
+and avoids synchronization issues during usage.
+
+Put your driver in the libraries/Session/drivers folder anywhere in your
+package paths. This includes the application directory, the system directory,
+or any path you add with $CI->load->add_package_path(). Your driver must be
+named CI_Session_<name>, and your filename must be Session_<name>.php,
+preferably also capitalized, such as::
+
+	CI_Session_foo in libraries/Session/drivers/Session_foo.php
+
+Then specify the driver by setting 'sess_driver' in your config.php file or as a
+parameter when loading the CI_Session object::
+
+	$config['sess_driver'] = 'foo';
+
+OR::
+
+	$CI->load->driver('session', array('sess_driver' => 'foo'));
+
+The driver specified by 'sess_driver' is automatically included as a valid
+driver. However, if you want to make a custom driver available as an option
+without making it the initially loaded driver, set 'sess_valid_drivers' in
+your config.php file to an array including your driver name::
+
+	$config['sess_valid_drivers'] = array('sess_driver');
 
-=========================== =============== =========================== ==========================================================================
-Preference                  Default         Options                     Description
-=========================== =============== =========================== ==========================================================================
-**sess_cookie_name**        ci_session      None                        The name you want the session cookie saved as.
-**sess_expiration**         7200            None                        The number of seconds you would like the session to last. The default
-                                                                        value is 2 hours (7200 seconds). If you would like a non-expiring
-                                                                        session set the value to zero: 0
-**sess_expire_on_close**    FALSE           TRUE/FALSE (boolean)        Whether to cause the session to expire automatically when the browser
-                                                                        window is closed.
-**sess_encrypt_cookie**     FALSE           TRUE/FALSE (boolean)        Whether to encrypt the session data.
-**sess_use_database**       FALSE           TRUE/FALSE (boolean)        Whether to save the session data to a database. You must create the
-                                                                        table before enabling this option.
-**sess_table_name**         ci_sessions     Any valid SQL table name    The name of the session database table.
-**sess_time_to_update**     300             Time in seconds             This options controls how often the session class will regenerate itself
-                                                                        and create a new session id.
-**sess_match_ip**           FALSE           TRUE/FALSE (boolean)        Whether to match the user's IP address when reading the session data.
-                                                                        Note that some ISPs dynamically changes the IP, so if you want a
-                                                                        non-expiring session you will likely set this to FALSE.
-**sess_match_useragent**    TRUE            TRUE/FALSE (boolean)        Whether to match the User Agent when reading the session data.
-=========================== =============== =========================== ==========================================================================
\ No newline at end of file
diff --git a/user_guide_src/source/libraries/trackback.rst b/user_guide_src/source/libraries/trackback.rst
index 07b2b2177..f9e0df882 100644
--- a/user_guide_src/source/libraries/trackback.rst
+++ b/user_guide_src/source/libraries/trackback.rst
@@ -114,7 +114,7 @@ store them. Here is a basic prototype for such a table::
 	 excerpt text NOT NULL,
 	 blog_name varchar(100) NOT NULL,
 	 tb_date int(10) NOT NULL,
-	 ip_address varchar(16) NOT NULL,
+	 ip_address varchar(45) NOT NULL,
 	 PRIMARY KEY `tb_id` (`tb_id`),
 	 KEY `entry_id` (`entry_id`)
 	);
diff --git a/user_guide_src/source/libraries/user_agent.rst b/user_guide_src/source/libraries/user_agent.rst
index 855ece29d..97abd2244 100644
--- a/user_guide_src/source/libraries/user_agent.rst
+++ b/user_guide_src/source/libraries/user_agent.rst
@@ -72,7 +72,7 @@ Returns TRUE/FALSE (boolean) if the user agent is a known web browser.
 	{
 	    echo 'You are using Safari.';
 	}
-	else if ($this->agent->is_browser())
+	elseif ($this->agent->is_browser())
 	{
 	    echo 'You are using a browser.';
 	}
@@ -94,7 +94,7 @@ Returns TRUE/FALSE (boolean) if the user agent is a known mobile device.
 	{
 	    $this->load->view('iphone/home');
 	}
-	else if ($this->agent->is_mobile())
+	elseif ($this->agent->is_mobile())
 	{
 	    $this->load->view('mobile/home');
 	}