new file mode 100644
@@ -0,0 +1,106 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2018, Google Inc.
+ *
+ * media_object.h - Media Device objects: entities, pads and links.
+ */
+#ifndef __LIBCAMERA_MEDIA_OBJECT_H__
+#define __LIBCAMERA_MEDIA_OBJECT_H__
+
+#include <string>
+#include <vector>
+
+#include <linux/media.h>
+
+namespace libcamera {
+
+class MediaDevice;
+class MediaEntity;
+
+class MediaObject
+{
+public:
+ MediaObject(unsigned int id) : id_(id) { }
+ virtual ~MediaObject() { }
+
+ unsigned int id() const { return id_; }
+
+protected:
+ unsigned int id_;
+};
+
+class MediaPad;
+class MediaLink : public MediaObject
+{
+ friend class MediaDevice;
+
+public:
+ ~MediaLink() { }
+
+ MediaPad *source() const { return source_; }
+ MediaPad *sink() const { return sink_; }
+ unsigned int flags() const { return flags_; }
+
+private:
+ MediaLink(const struct media_v2_link *link,
+ MediaPad *source, MediaPad *sink);
+ MediaLink(const MediaLink &) = delete;
+
+ MediaPad *source_;
+ MediaPad *sink_;
+ unsigned int flags_;
+};
+
+class MediaEntity;
+class MediaPad : public MediaObject
+{
+ friend class MediaDevice;
+
+public:
+ ~MediaPad();
+
+ unsigned int index() const { return index_; }
+ MediaEntity *entity() const { return entity_; }
+ unsigned int flags() const { return flags_; }
+ const std::vector<MediaLink *> &links() const { return links_; }
+
+ void addLink(MediaLink *link);
+
+private:
+ MediaPad(const struct media_v2_pad *pad, MediaEntity *entity);
+ MediaPad(const MediaPad &) = delete;
+
+ unsigned int index_;
+ MediaEntity *entity_;
+ unsigned int flags_;
+
+ std::vector<MediaLink *> links_;
+};
+
+class MediaEntity : public MediaObject
+{
+ friend class MediaDevice;
+
+public:
+ const std::string &name() const { return name_; }
+
+ const std::vector<MediaPad *> &pads() { return pads_; }
+
+ const MediaPad *getPadByIndex(unsigned int index);
+ const MediaPad *getPadById(unsigned int id);
+
+private:
+ MediaEntity(const struct media_v2_entity *entity);
+ MediaEntity(const MediaEntity &) = delete;
+ ~MediaEntity();
+
+ std::string name_;
+ std::string devnode_;
+
+ std::vector<MediaPad *> pads_;
+
+ void addPad(MediaPad *pad);
+};
+
+} /* namespace libcamera */
+#endif /* __LIBCAMERA_MEDIA_OBJECT_H__ */
new file mode 100644
@@ -0,0 +1,279 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * Copyright (C) 2018, Google Inc.
+ *
+ * media_object.cpp - Media device objects: entities, pads and links
+ */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <string.h>
+#include <sys/stat.h>
+
+#include <string>
+#include <vector>
+
+#include <linux/media.h>
+
+#include "log.h"
+#include "media_object.h"
+
+/**
+ * \file media_object.h
+ *
+ * Provides a class hierarchy that represent the corresponding of media
+ * objects exposed by the kernel's media controller APIs.
+ *
+ * Media Objects represented here are media entities, media pads and
+ * media links, created with informations as obtained by the
+ * MEDIA_IOC_G_TOPOLOGY ioctl call.
+ *
+ * MediaLink, MediaPad and MediaEntity are derived classes of the virtual
+ * base class MediaObject, which maintains a globally unique id for each object.
+ *
+ * Media objects have private constructors to restrict the number of classes
+ * that can instantiate them only to the 'friend' MediaDevice one. Media
+ * objects are in facts created when a MediaDevice gets populated.
+ */
+
+namespace libcamera {
+
+/**
+ * \class MediaObject
+ * \brief Base class for all media object types
+ *
+ * MediaObject is the virtual base class for all media objects in the
+ * media graph. Each object has a globally unique id assigned, and this
+ * base class provides that.
+ *
+ * MediaEntities, MediaPads and MediaLink are MediaObject derived classes.
+ */
+
+/**
+ * \fn MediaObject::MediaObject()
+ * \brief Construct a MediaObject with \a id
+ * \param id The globally unique media object id
+ */
+
+/**
+ * \fn MediaObject::id()
+ * \brief Retrieve the media object global id
+ * \return The media object globally unique id
+ */
+
+/**
+ * \var MediaObject::id_
+ * \brief The MediaObject globally unique id
+ */
+
+/**
+ * \class MediaLink
+ * \brief Media Link object
+ *
+ * A MediaLink represents a 'struct media_v2_link', with associated
+ * references to the MediaPad it connects and an internal status defined
+ * by the MEDIA_LNK_FL_* flags captured in flags_.
+ *
+ * MediaLink can be enabled and disabled, with the exception of
+ * immutable links (see MEDIA_LNK_FL_IMMUTABLE).
+ *
+ * MediaLinks are created between MediaPads inspecting the media graph
+ * topology and are stored in both the source and sink MediaPad they
+ * connect.
+ */
+
+/**
+ * \brief Construct a MediaLink
+ * \param link The media link representation
+ * \param source The MediaPad source
+ * \param sink The MediaPad sink
+ */
+MediaLink::MediaLink(const struct media_v2_link *link, MediaPad *source,
+ MediaPad *sink)
+ : MediaObject(link->id), source_(source),
+ sink_(sink), flags_(link->flags)
+{
+}
+
+/**
+ * \fn MediaLink::source()
+ * \brief Retrieve the media link source pad
+ * \return The source MediaPad
+ */
+
+/**
+ * \fn MediaLink::sink()
+ * \brief Retrieve the media link sink pad
+ * \return The sinks MediaPad
+ */
+
+/**
+ * \fn MediaLink::flags()
+ * \brief Retrieve the media link flags
+ * \return The link flags (MEDIA_LNK_FL_*)
+ */
+
+/**
+ * \class MediaPad
+ * \brief Media Pad object
+ *
+ * MediaPads represent a 'struct media_v2_pad', with associated list of
+ * links and a reference to the entity they belong to.
+ *
+ * MediaPads are connected to other MediaPads by MediaLinks, created
+ * inspecting the media graph topology. Data connection between pads can be
+ * enabled or disabled operating on the link that connects the two. See
+ * MediaLink.
+ *
+ * MediaPads are either 'source' pads, or 'sink' pads. This information is
+ * captured by the MEDIA_PAD_FL_* flags as stored in the flags_ member
+ * variable.
+ *
+ * Each MediaPad has a list of MediaLinks it is associated to. All links
+ * in a source pad are outbound links, while all links in a sink pad are
+ * inbound ones.
+ *
+ * Each MediaPad has a reference to the MediaEntity it belongs to.
+ */
+
+/**
+ * \brief Create a MediaPad
+ * \param pad The struct media_v2_pad kernel representation
+ * \param entity The MediaEntity this pad belongs to
+ */
+MediaPad::MediaPad(const struct media_v2_pad *pad, MediaEntity *entity)
+ : MediaObject(pad->id), index_(pad->index), entity_(entity),
+ flags_(pad->flags)
+{
+}
+
+/**
+ * \brief Release the list of links in the pad
+ *
+ * This function does not delete the MediaLink pointed by the links_ list
+ * entries.
+ */
+MediaPad::~MediaPad()
+{
+ links_.clear();
+}
+
+/**
+ * \fn MediaPad::index()
+ * \brief Retrieve the media pad index
+ * \return The 0-indexed MediaPad index
+ */
+
+/**
+ * \fn MediaPad::entity()
+ * \brief Retrieve the entity the media pad belongs to
+ * \return The MediaEntity the pad belongs to
+ */
+
+/**
+ * \fn MediaPad::flags()
+ * \brief Retrieve the media pad flags
+ * \return The MediaPad flags (MEDIA_PAD_FL_*)
+ */
+
+/**
+ * \fn MediaPad::links()
+ * \brief Retrieve all links in the media pad
+ * \return A list of MediaLinks associated with the media pad
+ */
+
+/**
+ * \brief Add a new link to this pad
+ * \param link The MediaLink to add
+ */
+void MediaPad::addLink(MediaLink *link)
+{
+ links_.push_back(link);
+}
+
+/**
+ * \class MediaEntity
+ * \brief Media entity
+ *
+ * A MediaEntity represents a 'struct media_v2_entity' with an associated
+ * list of MediaPads it contains.
+ *
+ * Entities are created inspecting the media graph topology, and MediaPads
+ * gets added as they are discovered.
+ *
+ * TODO: Add support for associating a devnode to the entity when integrating
+ * with DeviceEnumerator.
+ */
+
+/**
+ * \fn MediaEntity::name()
+ * \brief Retrieve the entity name
+ * \return The MediaEntity name
+ */
+
+/**
+ * \fn MediaEntity::pads()
+ * \brief Retrieve all pads of a media entity
+ * \return The list of the entity MediaPads
+ */
+
+/**
+ * \brief Get a pad in this entity by its index
+ * \param index The 0-indexed pad index
+ * \return The pad with index \a index
+ * \return nullptr if no pad is found at \a index
+ */
+const MediaPad *MediaEntity::getPadByIndex(unsigned int index)
+{
+ for (MediaPad *p : pads_)
+ if (p->index() == index)
+ return p;
+
+ return nullptr;
+}
+
+/**
+ * \brief Get a pad in this entity by its globally unique id
+ * \param id The pad globally unique id
+ * \return The pad with id \a id
+ * \return nullptr if not pad with \a id is found
+ */
+const MediaPad *MediaEntity::getPadById(unsigned int id)
+{
+ for (MediaPad *p : pads_)
+ if (p->id() == id)
+ return p;
+
+ return nullptr;
+}
+
+/**
+ * \brief Construct a MediaEntity
+ * \param entity The struct media_v2_entity kernel representation
+ */
+MediaEntity::MediaEntity(const struct media_v2_entity *entity)
+ : MediaObject(entity->id), name_(entity->name)
+{
+}
+
+/**
+ * \brief Release the list of pads in the entity
+ *
+ * This function does not delete the MediaPad instances pointed to by the
+ * pads_ list entries.
+ */
+MediaEntity::~MediaEntity()
+{
+ pads_.clear();
+}
+
+/**
+ * \brief Add \a pad to list of entity's pads
+ * \param pad The MediaPad to add
+ */
+void MediaEntity::addPad(MediaPad *pad)
+{
+ pads_.push_back(pad);
+}
+
+} /* namespace libcamera */
@@ -4,12 +4,14 @@ libcamera_sources = files([
'device_enumerator.cpp',
'log.cpp',
'main.cpp',
+ 'media_object.cpp',
'pipeline_handler.cpp',
])
libcamera_headers = files([
'include/device_enumerator.h',
'include/log.h',
+ 'include/media_object.h',
'include/pipeline_handler.h',
'include/utils.h',
])