Source code

Revision control

Other Tools

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef MediaEngineSource_h
#define MediaEngineSource_h
#include "MediaSegment.h"
#include "MediaTrackConstraints.h"
#include "mozilla/dom/MediaStreamTrackBinding.h"
#include "mozilla/media/MediaUtils.h"
#include "mozilla/RefPtr.h"
#include "mozilla/ThreadSafeWeakPtr.h"
#include "nsStringFwd.h"
namespace mozilla {
namespace dom {
class Blob;
struct MediaTrackSettings;
} // namespace dom
namespace ipc {
class PrincipalInfo;
} // namespace ipc
class MediaEnginePhotoCallback;
class MediaEnginePrefs;
class MediaTrack;
/**
* Callback interface for TakePhoto(). Either PhotoComplete() or PhotoError()
* should be called.
*/
class MediaEnginePhotoCallback {
public:
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaEnginePhotoCallback)
// aBlob is the image captured by MediaEngineSource. It is
// called on main thread.
virtual nsresult PhotoComplete(already_AddRefed<dom::Blob> aBlob) = 0;
// It is called on main thread. aRv is the error code.
virtual nsresult PhotoError(nsresult aRv) = 0;
protected:
virtual ~MediaEnginePhotoCallback() = default;
};
/**
* Lifecycle state of MediaEngineSource.
*/
enum MediaEngineSourceState {
kAllocated, // Allocated, not yet started.
kStarted, // Previously allocated or stopped, then started.
kStopped, // Previously started, then stopped.
kReleased // Not allocated.
};
/**
* The pure interface of a MediaEngineSource.
*
* Most sources are helped by the defaults implemented in MediaEngineSource.
*/
class MediaEngineSourceInterface {
public:
/**
* Return true if this is a fake source. I.e., if it is generating media
* itself rather than being an interface to underlying hardware.
*/
virtual bool IsFake() const = 0;
/**
* Gets the human readable name of this device.
*/
virtual nsString GetName() const = 0;
/**
* Gets the raw (non-anonymous) UUID of this device.
*/
virtual nsCString GetUUID() const = 0;
/**
* Gets the raw Group id of this device.
*/
virtual nsString GetGroupId() const = 0;
/**
* Get the enum describing the underlying type of MediaSource.
*/
virtual dom::MediaSourceEnum GetMediaSource() const = 0;
/**
* Override w/true if source does end-run around cross origin restrictions.
*/
virtual bool GetScary() const = 0;
/**
* Override w/a promise if source has frames, in order to potentially allow
* deferring success of source acquisition until first frame has arrived.
*/
virtual RefPtr<GenericNonExclusivePromise> GetFirstFramePromise() const {
return nullptr;
}
/**
* Called by MediaEngine to allocate an instance of this source.
*/
virtual nsresult Allocate(const dom::MediaTrackConstraints& aConstraints,
const MediaEnginePrefs& aPrefs, uint64_t aWindowID,
const char** aOutBadConstraint) = 0;
/**
* Called by MediaEngine when a MediaTrack has been provided for the source to
* feed data to.
*
* This must be called before Start.
*/
virtual void SetTrack(const RefPtr<MediaTrack>& aTrack,
const PrincipalHandle& aPrincipal) = 0;
/**
* Called by MediaEngine to start feeding data to the track.
*
* NB: Audio sources handle the enabling of pulling themselves.
*/
virtual nsresult Start() = 0;
/**
* This brings focus to the selected source, e.g. to bring a captured window
* to the front.
*
* We return one of the following:
* NS_OK - Success.
* NS_ERROR_NOT_AVAILABLE - For backends where focusing does not make sense.
* NS_ERROR_NOT_IMPLEMENTED - For backends where focusing makes sense, but
* is not yet implemented.
* NS_ERROR_FAILURE - Failures reported from underlying code.
*/
virtual nsresult FocusOnSelectedSource() = 0;
/**
* Applies new constraints to the capability selection for the underlying
* device.
*
* Should the constraints lead to choosing a new capability while the device
* is actively being captured, the device will restart using the new
* capability.
*
* We return one of the following:
* NS_OK - Successful reconfigure.
* NS_ERROR_INVALID_ARG - Couldn't find a capability fitting aConstraints.
* See aBadConstraint for details.
* NS_ERROR_UNEXPECTED - Reconfiguring the underlying device failed
* unexpectedly. This leaves the device in a stopped
* state.
*/
virtual nsresult Reconfigure(const dom::MediaTrackConstraints& aConstraints,
const MediaEnginePrefs& aPrefs,
const char** aOutBadConstraint) = 0;
/**
* Called by MediaEngine to stop feeding data to the track.
*
* Double-stopping is allowed and will return NS_OK. This is necessary
* sometimes during shutdown.
*
* NB: Audio sources handle the disabling of pulling themselves.
*/
virtual nsresult Stop() = 0;
/**
* Called by MediaEngine to deallocate an underlying device.
*/
virtual nsresult Deallocate() = 0;
/**
* Called by MediaEngine when it knows this MediaEngineSource won't be used
* anymore. Use it to clean up anything that needs to be cleaned up.
*/
virtual void Shutdown() = 0;
/**
* If implementation of MediaEngineSource supports TakePhoto(), the picture
* should be returned via aCallback object. Otherwise, it returns
* NS_ERROR_NOT_IMPLEMENTED.
*/
virtual nsresult TakePhoto(MediaEnginePhotoCallback* aCallback) = 0;
/**
* GetBestFitnessDistance returns the best distance the capture device can
* offer as a whole, given an accumulated number of ConstraintSets. Ideal
* values are considered in the first ConstraintSet only. Plain values are
* treated as Ideal in the first ConstraintSet. Plain values are treated as
* Exact in subsequent ConstraintSets. Infinity = UINT32_MAX e.g. device
* cannot satisfy accumulated ConstraintSets. A finite result may be used to
* calculate this device's ranking as a choice.
*/
virtual uint32_t GetBestFitnessDistance(
const nsTArray<const NormalizedConstraintSet*>& aConstraintSets)
const = 0;
/**
* Returns the current settings of the underlying device.
*
* Note that this might not be the settings of the underlying hardware.
* In case of a camera where we intervene and scale frames to avoid
* leaking information from other documents than the current one,
* GetSettings() will return the scaled resolution. I.e., the
* device settings as seen by js.
*/
virtual void GetSettings(dom::MediaTrackSettings& aOutSettings) const = 0;
};
/**
* Abstract base class for MediaEngineSources.
*
* Implements defaults for some common MediaEngineSourceInterface methods below.
* Also implements RefPtr support and an owning-thread model for thread safety
* checks in subclasses.
*/
class MediaEngineSource : public MediaEngineSourceInterface {
public:
// code inside webrtc.org assumes these sizes; don't use anything smaller
// without verifying it's ok
static const unsigned int kMaxDeviceNameLength = 128;
static const unsigned int kMaxUniqueIdLength = 256;
/**
* Returns true if the given source type is for video, false otherwise.
* Only call with real types.
*/
static bool IsVideo(dom::MediaSourceEnum aSource);
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MediaEngineSource)
NS_DECL_OWNINGEVENTTARGET
void AssertIsOnOwningThread() const {
NS_ASSERT_OWNINGTHREAD(MediaEngineSource);
}
// Not fake by default.
bool IsFake() const override;
// Not scary by default.
bool GetScary() const override;
// Returns NS_ERROR_NOT_AVAILABLE by default.
nsresult FocusOnSelectedSource() override;
// Shutdown does nothing by default.
void Shutdown() override;
// TakePhoto returns NS_ERROR_NOT_IMPLEMENTED by default,
// to tell the caller to fallback to other methods.
nsresult TakePhoto(MediaEnginePhotoCallback* aCallback) override;
// Returns a default distance of 0 for devices that don't have capabilities.
uint32_t GetBestFitnessDistance(
const nsTArray<const NormalizedConstraintSet*>& aConstraintSets)
const override {
return 0;
}
protected:
virtual ~MediaEngineSource();
};
} // namespace mozilla
#endif /* MediaEngineSource_h */