From f279615b003098555d8ca80e941ced0538237247 Mon Sep 17 00:00:00 2001 From: Raphael Kubo da Costa Date: Tue, 13 Dec 2022 14:35:57 +0100 Subject: [PATCH 1/5] Editorial: Export the "sensor task source" definition. Extension specifications may need to use to queue tasks in their own operations. --- index.bs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/index.bs b/index.bs index 009f03a..c5e3621 100644 --- a/index.bs +++ b/index.bs @@ -916,7 +916,7 @@ dictionary SensorOptions { A {{Sensor}} object has an associated [=platform sensor=]. -The [=task source=] for the [=tasks=] mentioned in this specification is the sensor task source. +The [=task source=] for the [=tasks=] mentioned in this specification is the sensor task source.
In the following example, firstly, we check whether the user agent has permission to access From e7c2bc41f922ea0638064e470a28a2cfd6329b00 Mon Sep 17 00:00:00 2001 From: Raphael Kubo da Costa Date: Tue, 13 Dec 2022 14:39:40 +0100 Subject: [PATCH 2/5] Mention algorithms from #429 in "Extensibility Definition Requirements". The new algorithms were defined in the "Sensor Type" section, but it makes sense to list them when describing what extension specifications may do. --- index.bs | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/index.bs b/index.bs index c5e3621..16b65a6 100644 --- a/index.bs +++ b/index.bs @@ -2066,6 +2066,11 @@ for each [=sensor types=]: For [=sensor types=] where multiple [=device sensor|sensors=] are common, [=extension specifications=] may choose not to define a [=default sensor=], especially when doing so would not make sense. +- A [=threshold check algorithm=], which returns a boolean indicating whether + two sensor readings differ enough to cause the [=latest readings=] map to + be updated. +- A [=reading quantization algorithm=], which may return a sensor reading + with reduced accuracy.

Automation

From 2f8702b8d7226410c2f02ade73a493fce5132b2f Mon Sep 17 00:00:00 2001 From: Raphael Kubo da Costa Date: Tue, 13 Dec 2022 16:23:31 +0100 Subject: [PATCH 3/5] Define a "pre-activation checks algorithm". Related to w3c/ambient-light#79, where we want to replace the "ambient-light" powerful feature with an integration with the Media Capture and Streams spec by only providing illuminance readouts if the same page has an active local video source. Part of it requires checking the above condition when `Sensor.start()` is called; the new algorithm introduced here does it in the "activate a sensor object" abstract operation. Additionally, `Sensor.start()` is now invoking "activate a sensor object" as a queued task, as we want it to run in the main event loop rather than in parallel since at least the Ambient Light Sensor implementation of the "pre-activation checks algorithm" needs access to the relevant global object and its internal slots. --- index.bs | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/index.bs b/index.bs index 16b65a6..a3c15b2 100644 --- a/index.bs +++ b/index.bs @@ -810,6 +810,10 @@ A [=sensor type=] may have an associated reading quantization algorithm, which takes a [=sensor reading=] and returns a less accurate [=sensor reading=]. +A [=sensor type=] may have an associated pre-activation checks +algorithm, which takes a {{Sensor}} instance and returns a boolean, to +perform extra checks before activating the given {{Sensor}} instance. +

Sensor

The current [=browsing context=]'s [=platform sensor=] must have: @@ -1169,7 +1173,7 @@ It represents a [=reading timestamp=]. but it is a tradeoff some User Agent might choose to make. --> 1. Queue a task to run [=notify error=] with [=this=] and |e| as arguments. 1. Return. - 1. Invoke [=activate a sensor object=] with [=this=] as argument. + 1. Queue a task to run [=activate a sensor object=] with [=this=] as argument.
@@ -1330,6 +1334,14 @@ to {{SensorErrorEventInit}}. :: None 1. Let |sensor| be the [=platform sensor=] associated with |sensor_instance|. + 1. Let |type| be |sensor|'s associated [=sensor type=]. + 1. If |type|'s [=pre-activation checks algorithm=] is defined: + 1. Let |result| be the result of invoking |type|'s [=pre-activation checks algorithm=] with |sensor_instance|. + 1. If |result| is false: + 1. Let |e| be the result of [=created|creating=] a "{{NotReadableError}}" {{DOMException}}. + + 1. Queue a task to run [=notify error=] with |sensor_instance| and |e|. + 1. Return. 1. [=set/Append=] |sensor_instance| to |sensor|'s set of [=activated sensor objects=]. 1. Invoke [=set sensor settings=] with |sensor| as argument. 1. Queue a task to run [=notify activated state=] with |sensor_instance| @@ -2071,6 +2083,8 @@ for each [=sensor types=]: be updated. - A [=reading quantization algorithm=], which may return a sensor reading with reduced accuracy. +- A [=pre-activation checks algorithm=] with extra steps that are run + before a {{Sensor}} instance is activated.

Automation

From 92fefabe9b117db7b4c8591c0c21ccccc07fdcda Mon Sep 17 00:00:00 2001 From: Raphael Kubo da Costa Date: Tue, 13 Dec 2022 16:28:08 +0100 Subject: [PATCH 4/5] Stop requiring sensor permissions names to be a non-empty set. Related to w3c/ambient-light#79, where we want to replace the "ambient-light" powerful feature with an integration with the Media Capture and Streams spec by only providing illuminance readouts if the same page has an active local video source. In this case, we rely on the Media Capture and Streams' permission model, as having an active local video source implicitly means the "camera" permission has already been granted. Mention the Ambient Light Sensor case and change the requirement for the snesor permissions name set. --- index.bs | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-) diff --git a/index.bs b/index.bs index a3c15b2..ef2cfbd 100644 --- a/index.bs +++ b/index.bs @@ -84,8 +84,12 @@ urlPrefix: https://w3c.github.io/geolocation-sensor/; spec: GEOLOCATION-SENSOR urlPrefix: https://w3c.github.io/proximity; spec: PROXIMITY type: dfn text: ProximitySensor; url: proximity-sensor-interface +urlPrefix: https://w3c.github.io/mediacapture-main/; spec: MEDIACAPTURE-STREAMS + type: dfn + text: stopped; url: source-stopped 
+spec: mediacapture-streams; type:dfn; text:source
 spec: webidl; type:dfn; text:attribute
 spec: webidl; type:dfn; text:dictionary member
 spec: webidl; type:dfn; text:identifier
@@ -448,6 +452,11 @@ payment service from within an iframe.
 
 Access to [=sensor readings=] are controlled by the Permissions API [[!PERMISSIONS]].
 
+Note: in specific cases such as [[AMBIENT-LIGHT]], integration with the
+Permissions API is done indirectly -- illuminance readings are provided only
+when at least one local video [=source=] is not [=muted=] or [=stopped=]. By
+definition, that implies the "camera" permission has been granted.
+
 
Mitigation strategies applied on a case by case basis

 
 Each [=sensor type=] will need to be assessed individually,
@@ -778,10 +787,13 @@ A [=sensor type=] has a [=ordered set|set=] of associated sensorssensor permission names.
+A [=sensor type=] has a [=ordered set|set=] of associated [=powerful
+feature/names=] referred to as sensor permission names.
 
 Note: multiple [=sensor types=] may share the same [=powerful feature/name=].
+In specific cases, [=extension specifications=] might choose to define an
+[=set/empty=] set of [=sensor permission names=] if their permission model is
+integrated with that of another specification.
 
 A [=sensor type=] has a [=permission revocation algorithm=].
 
@@ -2105,6 +2117,11 @@ for instance, "gyroscope" or "accelerometer". [=sensor fusion|Fusion sensors=] m
 [=request permission to use|request permission to access=] each of the sensors that are
 used as a source of fusion.
 
+Note: see the note in [[#permissions]]. In specific cases such as
+[[AMBIENT-LIGHT]], an [=extension specification=] may choose to rely on
+[=powerful feature/names=] defined in another specification rather than
+specifying their own [=sensor permission names=].
+
 Even though it might be difficult to reconstruct [=low-level=] [=sensor readings=] from
 fused data, some of the original information might be inferred. For example, it is easy to
 deduce user's orientation in space if absolute or geomagnetic orientation sensors are used,

From cbdb0224bf26d88b50fe3cebef2fb08d7c42f042 Mon Sep 17 00:00:00 2001
From: Raphael Kubo da Costa 
Date: Fri, 16 Dec 2022 19:17:52 +0100
Subject: [PATCH 5/5] Use "local camera source" instead of "local video
 source".

See the discussion in w3c/ambient-light#83 -- "local video source" could end
up including screen capture sessions.
---
 index.bs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/index.bs b/index.bs
index ef2cfbd..c398d9c 100644
--- a/index.bs
+++ b/index.bs
@@ -454,7 +454,7 @@ Access to [=sensor readings=] are controlled by the Permissions API [[!PERMISSIO
 
 Note: in specific cases such as [[AMBIENT-LIGHT]], integration with the
 Permissions API is done indirectly -- illuminance readings are provided only
-when at least one local video [=source=] is not [=muted=] or [=stopped=]. By
+when at least one local camera [=source=] is not [=muted=] or [=stopped=]. By
 definition, that implies the "camera" permission has been granted.
 
 
Mitigation strategies applied on a case by case basis