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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
* Copyright (C) 2019, Google Inc.
*
* request.cpp - Capture request handling
*/
#include <libcamera/request.h>
#include <map>
#include <libcamera/buffer.h>
#include <libcamera/camera.h>
#include <libcamera/stream.h>
#include "log.h"
/**
* \file request.h
* \brief Describes a frame capture request to be processed by a camera
*/
namespace libcamera {
LOG_DEFINE_CATEGORY(Request)
/**
* \enum Request::Status
* Request completion status
* \var Request::RequestPending
* The request hasn't completed yet
* \var Request::RequestComplete
* The request has completed
* \var Request::RequestCancelled
* The request has been cancelled due to capture stop
*/
/**
* \class Request
* \brief A frame capture request
*
* A Request allows an application to associate buffers and controls on a
* per-frame basis to be queued to the camera device for processing.
*/
/**
* \brief Create a capture request for a camera
* \param[in] camera The camera that creates the request
* \param[in] cookie Opaque cookie for application use
*
* The \a cookie is stored in the request and is accessible through the
* cookie() method at any time. It is typically used by applications to map the
* request to an external resource in the request completion handler, and is
* completely opaque to libcamera.
*
*/
Request::Request(Camera *camera, uint64_t cookie)
: camera_(camera), controls_(camera), cookie_(cookie),
status_(RequestPending)
{
}
Request::~Request()
{
for (auto it : bufferMap_) {
Buffer *buffer = it.second;
delete buffer;
}
}
/**
* \fn Request::controls()
* \brief Retrieve the request's ControlList
*
* Requests store a list of controls to be applied to all frames captured for
* the request. They are created with an empty list of controls that can be
* accessed through this method and updated with ControlList::operator[]() or
* ControlList::update().
*
* Only controls supported by the camera to which this request will be
* submitted shall be included in the controls list. Attempting to add an
* unsupported control causes undefined behaviour.
*
* \return A reference to the ControlList in this request
*/
/**
* \fn Request::buffers()
* \brief Retrieve the request's streams to buffers map
*
* Return a reference to the map that associates each Stream part of the
* request to the Buffer the Stream output should be directed to.
*
* \return The map of Stream to Buffer
*/
/**
* \brief Store a Buffer with its associated Stream in the Request
* \param[in] buffer The Buffer to store in the request
*
* Ownership of the buffer is passed to the request. It will be deleted when
* the request is destroyed after completing.
*
* A request can only contain one buffer per stream. If a buffer has already
* been added to the request for the same stream, this method returns -EEXIST.
*
* \return 0 on success or a negative error code otherwise
* \retval -EEXIST The request already contains a buffer for the stream
*/
int Request::addBuffer(std::unique_ptr<Buffer> buffer)
{
Stream *stream = buffer->stream();
auto it = bufferMap_.find(stream);
if (it != bufferMap_.end()) {
LOG(Request, Error) << "Buffer already set for stream";
return -EEXIST;
}
bufferMap_[stream] = buffer.release();
return 0;
}
/**
* \var Request::bufferMap_
* \brief Mapping of streams to buffers for this request
*
* The bufferMap_ tracks the buffers associated with each stream. If a stream is
* not utilised in this request there will be no buffer for that stream in the
* map.
*/
/**
* \brief Return the buffer associated with a stream
* \param[in] stream The stream the buffer is associated to
* \return The buffer associated with the stream, or nullptr if the stream is
* not part of this request
*/
Buffer *Request::findBuffer(Stream *stream) const
{
auto it = bufferMap_.find(stream);
if (it == bufferMap_.end())
return nullptr;
return it->second;
}
/**
* \fn Request::cookie()
* \brief Retrieve the cookie set when the request was created
* \return The request cookie
*/
/**
* \fn Request::status()
* \brief Retrieve the request completion status
*
* The request status indicates whether the request has completed successfully
* or with an error. When requests are created and before they complete the
* request status is set to RequestPending, and is updated at completion time
* to RequestComplete. If a request is cancelled at capture stop before it has
* completed, its status is set to RequestCancelled.
*
* \return The request completion status
*/
/**
* \fn Request::hasPendingBuffers()
* \brief Check if a request has buffers yet to be completed
*
* \return True if the request has buffers pending for completion, false
* otherwise
*/
/**
* \brief Validate the request and prepare it for the completion handler
*
* Requests that contain no buffers are invalid and are rejected.
*
* \return 0 on success or a negative error code otherwise
* \retval -EINVAL The request is invalid
*/
int Request::prepare()
{
if (bufferMap_.empty()) {
LOG(Request, Error) << "Invalid request due to missing buffers";
return -EINVAL;
}
for (auto const &pair : bufferMap_) {
Buffer *buffer = pair.second;
buffer->setRequest(this);
pending_.insert(buffer);
}
return 0;
}
/**
* \brief Complete a queued request
* \param[in] status The request completion status
*
* Mark the request as complete by updating its status to \a status.
*/
void Request::complete(Status status)
{
ASSERT(!hasPendingBuffers());
status_ = status;
}
/**
* \brief Complete a buffer for the request
* \param[in] buffer The buffer that has completed
*
* A request tracks the status of all buffers it contains through a set of
* pending buffers. This function removes the \a buffer from the set to mark it
* as complete. All buffers associate with the request shall be marked as
* complete by calling this function once and once only before reporting the
* request as complete with the complete() method.
*
* \return True if all buffers contained in the request have completed, false
* otherwise
*/
bool Request::completeBuffer(Buffer *buffer)
{
int ret = pending_.erase(buffer);
ASSERT(ret == 1);
buffer->setRequest(nullptr);
return !hasPendingBuffers();
}
} /* namespace libcamera */
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