displayengine/include/core/core_interface.h

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/*! @file core_interface.h
  @brief Interface file for core of the display subsystem.

  @details Display core is primarily used for loading and unloading different display device
  components viz primary, external and virtual. Display core is a statically linked library which
  runs in caller's process context.
*/
#ifndef __CORE_INTERFACE_H__
#define __CORE_INTERFACE_H__

#include <stdint.h>

#include "display_interface.h"
#include "sde_types.h"
#include "buffer_allocator.h"

class BufferSyncHandler;

/*! @brief Display engine interface version.

  @details Display engine interfaces are version tagged to maintain backward compatibility. This
  version is supplied as a default argument during display core initialization.

  Client may use an older version of interfaces and link to a higher version of display engine
  library, but vice versa is not allowed.

  A 32-bit client must use 32-bit display core library and a 64-bit client must use 64-bit display
  core library.

  Display engine interfaces follow default data structures alignment. Client must not override the
  default padding rules while using these interfaces.

  @warning It is assumed that client upgrades or downgrades display core interface all at once
  and recompile all binaries which use these interfaces. Mix and match of these interfaces can
  lead to unpredictable behaviour.

  @sa CoreInterface::CreateCore
*/
#define SDE_REVISION_MAJOR (1)
#define SDE_REVISION_MINOR (0)

#define SDE_VERSION_TAG ((uint32_t) ((SDE_REVISION_MAJOR << 24) | (SDE_REVISION_MINOR << 16) | \
                                    (sizeof(SDECompatibility) << 8) | sizeof(int *)))

namespace sde {

/*! @brief Forward declaration for debug handler.
*/
class DebugHandler;


/*! @brief Event data associated with hotplug event.

  @sa CoreEventHandler::Hotplug
*/
struct CoreEventHotplug {
  bool connected;   //!< True when device is connected.

  CoreEventHotplug() : connected(false) { }
};

/*! @brief Display core event handler implemented by the client.

  @details This class declares prototype for display core event handler methods which must be
  implemented by the client. Display core will use these methods to notify events to the client.
  Client must post heavy-weight event handling to a separate thread and unblock display core thread
  instantly.

  @sa CoreInterface::CreateCore
*/
class CoreEventHandler {
 public:
  /*! @brief Event handler for Hotplug event.

    @details Event generated when a display device is connected or disconnected. Applicable to
    detachable displays only.

    @param[in] \link CoreEventHotplug \endlink

    @return \link DisplayError \endlink
  */
  virtual DisplayError Hotplug(const CoreEventHotplug &hotplug) = 0;

 protected:
  virtual ~CoreEventHandler() { }
};

/*! @brief Display core interface.

  @details This class defines display core interfaces. It contains methods which client shall use
  to create/destroy different display devices. This interface is created during display core
  CreateCore() and remains valid until DestroyCore().

  @sa CoreInterface::CreateCore
  @sa CoreInterface::DestroyCore
*/
class CoreInterface {
 public:
  /*! @brief Method to create and get handle to display core interface.

    @details This method is the entry point into the display core. Client can create and operate on
    different display devices only through a valid interface handle obtained using this method. An
    object of display core is created and handle to this object is returned via output parameter.
    This interface shall be called only once.

    @param[in] event_handler \link CoreEventHandler \endlink
    @param[in] debug_handler \link DebugHandler \endlink
    @param[in] buffer_allocator \link BufferAllocator \endlink
    @param[in] buffer_sync_handler \link BufferSyncHandler \endlink
    @param[out] interface \link CoreInterface \endlink
    @param[in] version \link SDE_VERSION_TAG \endlink. Client must not override this argument.

    @return \link DisplayError \endlink

    @sa DestroyCore
  */
  static DisplayError CreateCore(CoreEventHandler *event_handler, DebugHandler *debug_handler,
                                 BufferAllocator *buffer_allocator,
                                 BufferSyncHandler *buffer_sync_handler, CoreInterface **interface,
                                 uint32_t version = SDE_VERSION_TAG);

  /*! @brief Method to release handle to display core interface.

    @details The object of corresponding display core is destroyed when this method is invoked.
    Client must explicitly destroy all created display device objects associated with this handle
    before invoking this method.

    @param[in] interface \link CoreInterface \endlink

    @return \link DisplayError \endlink

    @sa CreateCore
  */
  static DisplayError DestroyCore();

  /*! @brief Method to create a display device for a given type.

    @details Client shall use this method to create each of the connected display type. A handle to
    interface associated with this object is returned via output parameter which can be used to
    interact further with the display device.

    @param[in] type \link DisplayType \endlink
    @param[in] event_handler \link DisplayEventHandler \endlink
    @param[out] interface \link DisplayInterface \endlink

    @return \link DisplayError \endlink

    @sa DestroyDisplay
  */
  virtual DisplayError CreateDisplay(DisplayType type, DisplayEventHandler *event_handler,
                                     DisplayInterface **interface) = 0;

  /*! @brief Method to destroy a display device.

    @details Client shall use this method to destroy each of the created display device objects.

    @param[in] interface \link DisplayInterface \endlink

    @return \link DisplayError \endlink

    @sa CreateDisplay
  */
  virtual DisplayError DestroyDisplay(DisplayInterface *interface) = 0;

 protected:
  virtual ~CoreInterface() { }
};

}  // namespace sde

#endif  // __CORE_INTERFACE_H__