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#include "iplugin.h"
#include "iplugin_p.h"
#include "pluginmanager.h"
#include "pluginspec.h"
/*!
\class ExtensionSystem::IPlugin
\mainclass
\brief Base class for all plugins.
The IPlugin class is an abstract class that must be implemented
once for each plugin.
A plugin consists of two parts: A description file, and a library
that at least contains the IPlugin implementation.
\tableofcontents
\section1 Plugin Specification
The plugin specification file is an xml file that contains all
information that are necessary for loading the plugin's library,
plus some textual descriptions. The file must be located in
(a subdir of) one of the plugin manager's plugin search paths,
and must have the \c .xml extension.
\section2 Main Tag
The root tag is \c plugin. It has mandatory attributes \c name
and \c version, and an optional \c compatVersion.
\table
\header
\o Tag
\o Meaning
\row
\o plugin
\o Root element in a plugin's xml file.
\endtable
\table
\header
\o Attribute
\o Meaning
\row
\o name
\o This is used as an identifier for the plugin and can e.g.
be referenced in other plugin's dependencies. It is
also used to construct the name of the plugin library
as \c lib[name].[dll|.so|.dylib].
\row
\o version
\o Version string in the form \c {"x.y.z_n"}, used for identifying
the plugin.
\row
\o compatVersion
\o Compatibility version. Optional. If not given, it is implicitly
set to the same value as \c version. The compatibility version
is used to resolve dependencies on this plugin. See
\l {Dependencies}{Dependencies} for details.
\endtable
\section2 Plugin-describing Tags
These are direct children of the \c plugin tag, and are solely used
for more detailed (user centric) description of the plugin. All of these
are optional.
\table
\header
\o Tag
\o Meaning
\row
\o vendor
\o String that describes the plugin creator/vendor,
like \c {MyCompany}.
\row
\o copyright
\o A short copyright notice, like \c {(C) 2007-2008 MyCompany}.
\row
\o license
\o Possibly multi-line license information about the plugin.
\row
\o description
\o Possibly multi-line description of what the plugin is supposed
to provide.
\row
\o url
\o Link to further information about the plugin, like
\c {http://www.mycompany-online.com/products/greatplugin}.
\endtable
\section2 Dependencies
A plugin can have dependencies on other plugins. These are
specified in the plugin's xml file as well, to ensure that
these other plugins are loaded before this plugin.
Dependency information consists of the name of the required plugin
(lets denote that as \c {dependencyName}),
and the required version of the plugin (\c {dependencyVersion}).
A plugin with given \c name, \c version and \c compatVersion matches
the dependency if
\list
\o its \c name matches \c dependencyName, and
\o \c {compatVersion <= dependencyVersion <= version}.
\endlist
The xml element that describes dependencies is the \c dependency tag,
with required attributes \c name and \c version. It is an
optional direct child of the \c plugin tag and can appear multiple times.
\table
\header
\o Tag
\o Meaning
\row
\o dependency
\o Describes a dependency on another plugin.
\endtable
\table
\header
\o Attribute
\o Meaning
\row
\o name
\o The name of the plugin, on which this plugin relies.
\row
\o version
\o The version to which the plugin must be compatible to
fill the dependency, in the form \c {"x.y.z_n"}.
\endtable
\section2 Example \c plugin.xml
\code
MyCompany
(C) 2007 MyCompany
This is a default license bla
blubbblubb
end of terms
This plugin is just a test.
it demonstrates the great use of the plugin spec.
http://www.mycompany-online.com/products/greatplugin
\endcode
The first dependency could for example be matched by a plugin with
\code
\endcode
since the name matches, and the version \c "2.3.0_2" given in the dependency tag
lies in the range of \c "2.2.0" and \c "3.1.0".
\section2 A Note on Plugin Versions
Plugin versions are in the form \c "x.y.z_n" where, x, y, z and n are
non-negative integer numbers. You don't have to specify the version
in this full form - any left-out part will implicitly be set to zero.
So, \c "2.10_2" is equal to \c "2.10.0_2", and "1" is the same as "1.0.0_0".
\section1 Plugin Implementation
Plugins must provide one implementation of the IPlugin class, located
in a library that matches the \c name attribute given in their
xml description. The IPlugin implementation must be exported and
made known to Qt's plugin system via the Q_EXPORT_PLUGIN macro, see the
Qt documentation for details on that.
After the plugins' xml files have been read, and dependencies have been
found, the plugin loading is done in three phases:
\list 1
\o All plugin libraries are loaded in 'root-to-leaf' order of the
dependency tree.
\o All plugins' initialize methods are called in 'root-to-leaf' order
of the dependency tree. This is a good place to put
objects in the plugin manager's object pool.
\o All plugins' extensionsInitialized methods are called in 'leaf-to-root'
order of the dependency tree. At this point, plugins can
be sure that all plugins that depend on this plugin have
been initialized completely (implying that they have put
objects in the object pool, if they want that during the
initialization sequence).
\endlist
If library loading or initialization of a plugin fails, all plugins
that depend on that plugin also fail.
Plugins have access to the plugin manager
(and its object pool) via the PluginManager::instance()
method.
*/
/*!
\fn bool IPlugin::initialize(const QStringList &arguments, QString *errorString)
\brief Called after the plugin has been loaded and the IPlugin instance
has been created.
The initialize methods of plugins that depend
on this plugin are called after the initialize method of this plugin
has been called. Plugins should initialize their internal state in this
method. Returns if initialization of successful. If it wasn't successful,
the \a errorString should be set to a user-readable message
describing the reason.
\sa extensionsInitialized()
*/
/*!
\fn void IPlugin::extensionsInitialized()
\brief Called after the IPlugin::initialize() method has been called,
and after both the IPlugin::initialize() and IPlugin::extensionsInitialized()
methods of plugins that depend on this plugin have been called.
In this method, the plugin can assume that plugins that depend on
this plugin are fully 'up and running'. It is a good place to
look in the plugin manager's object pool for objects that have
been provided by dependent plugins.
\sa initialize()
*/
/*!
\fn IPlugin::ShutdownFlag IPlugin::aboutToShutdown()
\brief Called during a shutdown sequence in the same order as initialization
before the plugins get deleted in reverse order.
This method should be used to disconnect from other plugins,
hide all UI, and optimize shutdown in general.
If a plugin needs to delay the real shutdown for a while, for example if
it needs to wait for external processes to finish for a clean shutdown,
the plugin can return IPlugin::AsynchronousShutdown from this method. This
will keep the main event loop running after the aboutToShutdown() sequence
has finished, until all plugins requesting AsynchronousShutdown have sent
the asynchronousShutdownFinished() signal.
The default implementation of this method does nothing and returns
IPlugin::SynchronousShutdown.
Returns IPlugin::AsynchronousShutdown if the plugin needs to perform
asynchronous actions before performing the shutdown.
\sa asynchronousShutdownFinished()
*/
/*!
\fn void IPlugin::asynchronousShutdownFinished()
Sent by the plugin implementation after a asynchronous shutdown
is ready to proceed with the shutdown sequence.
\sa aboutToShutdown()
*/
using namespace ExtensionSystem;
/*!
\fn IPlugin::IPlugin()
\internal
*/
IPlugin::IPlugin()
: d(new Internal::IPluginPrivate())
{
}
/*!
\fn IPlugin::~IPlugin()
\internal
*/
IPlugin::~IPlugin()
{
PluginManager *pm = PluginManager::instance();
foreach (QObject *obj, d->addedObjectsInReverseOrder)
pm->removeObject(obj);
qDeleteAll(d->addedObjectsInReverseOrder);
d->addedObjectsInReverseOrder.clear();
delete d;
d = 0;
}
/*!
\fn PluginSpec *IPlugin::pluginSpec() const
Returns the PluginSpec corresponding to this plugin.
This is not available in the constructor.
*/
PluginSpec *IPlugin::pluginSpec() const
{
return d->pluginSpec;
}
/*!
\fn void IPlugin::addObject(QObject *obj)
Convenience method that registers \a obj in the plugin manager's
plugin pool by just calling PluginManager::addObject().
*/
void IPlugin::addObject(QObject *obj)
{
PluginManager::instance()->addObject(obj);
}
/*!
\fn void IPlugin::addAutoReleasedObject(QObject *obj)
Convenience method for registering \a obj in the plugin manager's
plugin pool. Usually, registered objects must be removed from
the object pool and deleted by hand.
Objects added to the pool via addAutoReleasedObject are automatically
removed and deleted in reverse order of registration when
the IPlugin instance is destroyed.
\sa PluginManager::addObject()
*/
void IPlugin::addAutoReleasedObject(QObject *obj)
{
d->addedObjectsInReverseOrder.prepend(obj);
PluginManager::instance()->addObject(obj);
}
/*!
\fn void IPlugin::removeObject(QObject *obj)
Convenience method that unregisters \a obj from the plugin manager's
plugin pool by just calling PluginManager::removeObject().
*/
void IPlugin::removeObject(QObject *obj)
{
PluginManager::instance()->removeObject(obj);
}