/*============================================================================

The Medical Imaging Interaction Toolkit (MITK)

Copyright (c) German Cancer Research Center (DKFZ)
All rights reserved.

Use of this source code is governed by a 3-clause BSD license that can be
found in the LICENSE file.

============================================================================*/


#ifndef BERRYIEXTENSIONREGISTRY_H
#define BERRYIEXTENSIONREGISTRY_H

#include <org_blueberry_core_runtime_Export.h>

#include "berrySmartPointer.h"

#include <QList>
#include <QtPlugin>

class QTranslator;

namespace berry {

struct IConfigurationElement;
struct IContributor;
struct IExtension;
struct IExtensionPoint;
struct IExtensionPointFilter;
struct IRegistryEventListener;

/**
 * The extension registry holds the master list of all
 * discovered namespaces, extension points and extensions.
 * <p>
 * The extension registry can be queried, by name, for
 * extension points and extensions.
 * </p>
 * <p>
 * The various objects that describe the contents of the extension registry
 * ({@link IExtensionPoint}, {@link IExtension}, and {@link IConfigurationElement})
 * are intended for relatively short-term use. Clients that deal with these objects
 * must be aware that they may become invalid if the declaring plug-in is updated
 * or uninstalled. If this happens, all methods on these object except
 * <code>isValid()</code> will throw {@link InvalidRegistryObjectException}.
 * Code in a plug-in that has declared that it is not dynamic aware (or not declared
 * anything) can safely ignore this issue, since the registry would not be
 * modified while it is active. However, code in a plug-in that declares that it
 * is dynamic aware must be careful if it accesses extension registry objects,
 * because it's at risk if plug-in are removed. Similarly, tools that analyze
 * or display the extension registry are vulnerable. Client code can pre-test for
 * invalid objects by calling <code>isValid()</code>, which never throws this exception.
 * However, pre-tests are usually not sufficient because of the possibility of the
 * extension registry object becoming invalid as a result of a concurrent activity.
 * At-risk clients must treat <code>InvalidRegistryObjectException</code> as if it
 * were a checked exception. Also, such clients should probably register a listener
 * with the extension registry so that they receive notification of any changes to
 * the registry.
 * </p>
 * <p>
 * Extensions and extension points are declared by generic entities called
 * \c namespaces . The only fact known about namespaces is that they
 * have unique string-based identifiers. One example of a namespace
 * is a plug-in, for which the namespace id is the plug-in id.
 * </p><p>
 * This interface is not intended to be implemented by clients.
 * </p>
 */
struct org_blueberry_core_runtime_EXPORT IExtensionRegistry
{

  virtual ~IExtensionRegistry();

  /**
   * Returns all configuration elements from all extensions configured
   * into the identified extension point. Returns an empty list if the extension
   * point does not exist, has no extensions configured, or none of the extensions
   * contain configuration elements.
   *
   * @param extensionPointId the unique identifier of the extension point
   *    (e.g. <code>"org.blueberry.core.applications"</code>)
   * @return the configuration elements
   */
  virtual QList<SmartPointer<IConfigurationElement> > GetConfigurationElementsFor(
      const QString& extensionPointId) const = 0;

  /**
   * Returns all configuration elements from all extensions configured
   * into the identified extension point. Returns an empty list if the extension
   * point does not exist, has no extensions configured, or none of the extensions
   * contain configuration elements.
   *
   * @param namespaze the namespace for the extension point
   *    (e.g. <code>"org.eclipse.core.resources"</code>)
   * @param extensionPointName the simple identifier of the
   *    extension point (e.g. <code>"builders"</code>)
   * @return the configuration elements
   */
  virtual QList<SmartPointer<IConfigurationElement> > GetConfigurationElementsFor(
      const QString& namespaze, const QString& extensionPointName) const = 0;

  /**
   * Returns all configuration elements from the identified extension.
   * Returns an empty array if the extension does not exist or
   * contains no configuration elements.
   *
   * @param namespaze the namespace for the extension point
   *    (e.g. <code>"org.eclipse.core.resources"</code>)
   * @param extensionPointName the simple identifier of the
   *    extension point (e.g. <code>"builders"</code>)
   * @param extensionId the unique identifier of the extension
   *    (e.g. <code>"com.example.acme.coolbuilder"</code>)
   * @return the configuration elements
   */
  virtual QList<SmartPointer<IConfigurationElement> > GetConfigurationElementsFor(
      const QString& namespaze, const QString& extensionPointName, const QString& extensionId) const = 0;

  /**
   * Returns the specified extension in this extension registry,
   * or <code>null</code> if there is no such extension.
   *
   * @param extensionId the unique identifier of the extension
   *    (e.g. <code>"com.example.acme.coolbuilder"</code>)
   * @return the extension, or <code>null</code>
   */
  virtual SmartPointer<IExtension> GetExtension(const QString& extensionId) const = 0;

  /**
   * Returns the specified extension in this extension registry,
   * or <code>null</code> if there is no such extension.
   * The first parameter identifies the extension point, and the second
   * parameter identifies an extension plugged in to that extension point.
   *
   * @param extensionPointId the unique identifier of the extension point
   *    (e.g. <code>"org.eclipse.core.resources.builders"</code>)
   * @param extensionId the unique identifier of the extension
   *    (e.g. <code>"com.example.acme.coolbuilder"</code>)
   * @return the extension, or <code>null</code>
   */
  virtual SmartPointer<IExtension> GetExtension(const QString& extensionPointId,
                                                const QString& extensionId) const = 0;

  /**
   * Returns the specified extension in this extension registry,
   * or <code>null</code> if there is no such extension.
   * The first two parameters identify the extension point, and the third
   * parameter identifies an extension plugged in to that extension point.
   *
   * @param namespaze the namespace for the extension point
   *    (e.g. <code>"org.eclipse.core.resources"</code>)
   * @param extensionPointName the simple identifier of the
   *    extension point (e.g. <code>"builders"</code>)
   * @param extensionId the unique identifier of the extension
   *    (e.g. <code>"com.example.acme.coolbuilder"</code>)
   * @return the extension, or <code>null</code>
   */
  virtual SmartPointer<IExtension> GetExtension(const QString& namespaze,
                                                const QString& extensionPointName,
                                                const QString& extensionId) const = 0;

  /**
   * Returns the extension point with the given extension point identifier
   * in this extension registry, or <code>null</code> if there is no such
   * extension point.
   *
   * @param extensionPointId the unique identifier of the extension point
   *    (e.g., <code>"org.blueberry.core.applications"</code>)
   * @return the extension point, or <code>null</code>
   */
  virtual SmartPointer<IExtensionPoint> GetExtensionPoint(const QString& extensionPointId) const = 0;

  /**
   * Returns the extension point in this extension registry
   * with the given namespace and extension point simple identifier,
   * or <code>null</code> if there is no such extension point.
   *
   * @param namespaze the namespace for the given extension point
   *    (e.g. <code>"org.eclipse.core.resources"</code>)
   * @param extensionPointName the simple identifier of the
   *    extension point (e.g. <code>"builders"</code>)
   * @return the extension point, or <code>null</code>
   */
  virtual SmartPointer<IExtensionPoint> GetExtensionPoint(const QString& namespaze,
                                                          const QString& extensionPointName) const = 0;

  /**
   * Returns all extension points known to this extension registry.
   * Returns an empty array if there are no extension points.
   *
   * @return the extension points known to this extension registry
   */
  virtual QList<SmartPointer<IExtensionPoint> > GetExtensionPoints() const = 0;

  /**
   * Returns all extension points declared in the given namespace. Returns an empty array if
   * there are no extension points declared in the namespace.
   *
   * @param namespaze the namespace for the extension points
   *    (e.g. <code>"org.eclipse.core.resources"</code>)
   * @return the extension points in this registry declared in the given namespace
   */
  virtual QList<SmartPointer<IExtensionPoint> > GetExtensionPoints(const QString& namespaze) const = 0;

  /**
   * Returns all extension points supplied by the contributor, or <code>null</code>
   * if there are no such extension points.
   *
   * @param contributor the contributor for the extensions (for OSGi registry, bundles and
   * fragments are different contributors)
   * @return the extension points, or <code>null</code>
   * @since 3.4
   */
  virtual QList<SmartPointer<IExtensionPoint> > GetExtensionPoints(
      const SmartPointer<IContributor>& contributor) const = 0;

  /**
   * Returns all extensions declared in the given namespace. Returns an empty array if
   * no extensions are declared in the namespace.
   *
   * @param namespaze the namespace for the extensions
   *    (e.g. <code>"org.eclipse.core.resources"</code>)
   * @return the extensions in this registry declared in the given namespace
   */
  virtual QList<SmartPointer<IExtension> > GetExtensions(const QString& namespaze) const = 0;

  /**
   * Returns all extensions supplied by the contributor, or <code>null</code> if there
   * are no such extensions.
   * @param contributor the contributor for the extensions (for OSGi registry, bundles and
   * fragments are different contributors)
   * @return the extensions, or <code>null</code>
   */
  virtual QList<SmartPointer<IExtension> > GetExtensions(const SmartPointer<IContributor>& contributor) const = 0;

  /**
   * Returns all namespaces currently used by extensions and extension points in this
   * registry. Returns an empty array if there are no known extensions/extension points
   * in this registry.
   * <p>
   * The fully-qualified name of an extension point or an extension consist of
   * a namespace and a simple name (much like a qualified Java class name consist
   * of a package name and a class name). The simple names are presumed to be unique
   * in the namespace.
   * </p>
   * @return all namespaces known to this registry
   */
  virtual QList<QString> GetNamespaces() const = 0;

  /**
   * Adds to this extension registry an extension point(s), extension(s), or
   * a combination of those described by the XML file. The information in
   * the XML file should be supplied in the same format as the plugin.xml; in fact,
   * Plug-in Manifest editor can be used to prepare the XML file. The top token
   * of the contribution (normally, "plugin" or "fragment" in the Plug-in Manifest
   * editor) is ignored by this method.
   * <p>
   * This method is an access controlled method. Proper token (master token or user token) should
   * be passed as an argument. Two registry keys are set in the registry constructor:
   * master token and a user token. Master token allows all operations; user token allows
   * non-persisted registry elements to be modified.
   * </p>
   *
   * @param is stream open on the XML file. The XML file can contain an extension
   *        point(s) or/and extension(s) described in the format similar to plugin.xml. The method
   *        closes the device before returning.
   * @param contributor the contributor making this contribution.
   * @param persist indicates if the contribution(s) should be stored in the registry cache. If <code>false</code>,
   *        contribution is not persisted in the registry cache and is lost on BlueBerry restart
   * @param name optional name of the contribution. Used for error reporting; might be <code>QString()</code>
   * @param translationBundle optional translator used for translations; might be <code>nullptr</code>
   * @param token the key used to check permissions
   * @return <code>true</code> if the contribution was successfully processed and <code>false</code> otherwise
   * @throws ctkInvalidArgumentException if an incorrect token is passed
   *
   * @see IContributor
   */
  virtual bool AddContribution(QIODevice* is, const SmartPointer<IContributor>& contributor,
                               bool persist, const QString& name, QTranslator* translationBundle, QObject* token) = 0;

  /**
   * Removes the given extension from this registry.
   * <p>
   * This method is an access controlled method. Proper token (master token or user token) should
   * be passed as an argument. Two registry keys are set in the registry constructor:
   * master token and a user token. Master token allows all operations; user token only
   * allows non-persisted registry elements to be modified.
   * </p>
   *
   * @param extension extension to be removed
   * @param token the key used to check permissions
   * @return <code>true</code> if the extension was successfully removed, and <code>false</code> otherwise
   * @throws ctkInvalidArgumentException if an incorrect token is passed
   */
  virtual bool RemoveExtension(const SmartPointer<IExtension>& extension, QObject* token) = 0;

  /**
   * Removes the specified extension point from this registry.
   * <p>
   * This method is an access controlled method. Proper token (master token or user token) should
   * be passed as an argument. Two registry keys are set in the registry constructor:
   * master token and a user token. Master token allows all operations; user token only
   * allows non-persisted registry elements to be modified.
   * </p>
   *
   * @param extensionPoint extension point to be removed
   * @param token the key used to check permissions
   * @return <code>true</code> if the extension point was successfully removed, and
   *         <code>false</code> otherwise
   * @throws ctkInvalidArgumentException if incorrect token is passed
   */
  virtual bool RemoveExtensionPoint(const SmartPointer<IExtensionPoint>& extensionPoint, QObject* token) = 0;

  /**
   * Call this method to properly stop the registry. The method stops registry event processing
   * and writes out cache information to be used in the next run. This is an access controlled
   * method; master token is required.
   * <p>
   * This method is an access controlled method. Master token should be passed as an argument.
   * </p>
   * @param token master token for the registry
   * @throws IllegalArgumentException if incorrect token is passed
   */
  virtual void Stop(QObject* token) = 0;

  /**
   * Adds the given listener for registry change events related to the specified
   * extension point or for changes to all extension points and underlying
   * extensions if the \c extensionPointId argument is empty.
   * <p>
   * Depending on activity, listeners of this type might receive a large number
   * of modifications and negatively impact overall system performance. Whenever
   * possible, consider registering listener specific to an extension point rather
   * than a "global" listener.
   * </p><p>
   * Once registered, a listener starts receiving notification of changes to
   * the registry. Registry change notifications are sent asynchronously.
   * The listener continues to receive notifications until it is removed.
   * </p><p>
   * This method has no effect if the listener is already registered.
   * </p>
   * @param listener the listener
   * @param extensionPointId the unique identifier of extension point
   * @see IExtensionPoint#GetUniqueIdentifier()
   */
  virtual void AddListener(IRegistryEventListener* listener, const QString& extensionPointId = QString()) = 0;

  /**
   * Adds the given listener for registry change events for extension points
   * matching the provided filter.
   * <p>
   * Depending on activity, listeners of this type might receive a large number
   * of modifications and negatively impact overall system performance. Whenever
   * possible, consider registering listener specific to an extension point rather
   * than a "global" listener.
   * </p><p>
   * Once registered, a listener starts receiving notification of changes to
   * the registry. Registry change notifications are sent asynchronously.
   * The listener continues to receive notifications until it is removed.
   * </p><p>
   * This method has no effect if the listener is already registered.
   * </p>
   * @param listener the listener
   * @param filter An extension point filter
   * @see ExtensionTracker
   */
  virtual void AddListener(IRegistryEventListener *listener, const IExtensionPointFilter& filter) = 0;

  /**
   * Removes the given registry change listener from this registry.
   * <p>
   * This method has no effect if the listener is not registered.
   * </p>
   * @param listener the listener
   * @see #AddListener(IRegistryEventListener*, const QString&)
   */
   virtual void RemoveListener(IRegistryEventListener* listener) = 0;

  /**
   * Call this method to determine if this extension registry supports multiple languages.
   * <p>
   * See the runtime option "-registryMultiLanguage" for enabling multi-language
   * support.
   * </p>
   * @return <code>true</code> if multiple languages are supported by this
   * instance of the extension registry; <code>false</code> otherwise.
   */
  virtual bool IsMultiLanguage() const = 0;
};

}

Q_DECLARE_INTERFACE(berry::IExtensionRegistry, "org.blueberry.service.IExtensionRegistry")

#endif // BERRYIEXTENSIONREGISTRY_H
