The Trunk: Kernel-mt.1285.mcz

Marcel Taeumel uploaded a new version of Kernel to project The Trunk:
http://source.squeak.org/trunk/Kernel-mt.1285.mcz

==================== Summary ====================

Name: Kernel-mt.1285
Author: mt
Time: 13 December 2019, 2:25:24.279249 pm
UUID: 1c18d133-29d7-6049-a7be-40a8d045b474
Ancestors: Kernel-mt.1284

Improves documentation in EventSensor.

=============== Diff against Kernel-mt.1284 ===============

Item was changed:
  Object subclass: #EventSensor
  instanceVariableNames: 'mouseButtons mousePosition mouseWheelDelta keyboardBuffer interruptKey interruptSemaphore eventQueue inputSemaphore lastEventPoll hasInputSemaphore'
  classVariableNames: 'ButtonDecodeTable EventPollPeriod EventTicklerProcess InterruptSemaphore InterruptWatcherProcess KeyDecodeTable'
  poolDictionaries: 'EventSensorConstants'
  category: 'Kernel-Processes'!
 
+ !EventSensor commentStamp: 'mt 12/13/2019 13:57' prior: 0!
- !EventSensor commentStamp: 'dtl 1/30/2016 14:44' prior: 0!
  An EventSensor is an interface to the user input devices.
  There is at least one instance of EventSensor named Sensor in the system.
 
  EventSensor is a replacement for the earlier InputSensor implementation based on a set of (optional) event primitives. An EventSensor updates its state when events are received so that all state based users of Sensor (e.g., Sensor keyboard, Sensor leftShiftDown, Sensor mouseButtons) will work exactly as before, by moving the current VM mechanisms into EventSensor itself. An optional input semaphore is part of the new design.
 
  For platforms that support true asynchronous event notification, the semaphore will be signaled to indicate pending events.
  On platforms that do not support asynchronous notifications about events, the UI will have to poll EventSensor periodically to read events from the VM.
 
  Instance variables:
  mouseButtons <Integer> - mouse button state as replacement for primMouseButtons
  mousePosition <Point> - mouse position as replacement for primMousePt
  keyboardBuffer <SharedQueue> - keyboard input buffer
  interruptKey <Integer> - currently defined interrupt key
  interruptSemaphore <Semaphore> - the semaphore signaled when the interruptKey is detected
  eventQueue <SharedQueue> - an optional event queue for event driven applications
  inputSemaphore <Semaphore>- the semaphore signaled by the VM if asynchronous event notification is supported
  lastEventPoll <Integer> - the last millisecondClockValue at which we called fetchMoreEvents
  hasInputSemaphore <Boolean> - true if my inputSemaphore has actually been signaled at least once.
 
  Class variables:
  ButtonDecodeTable <ByteArray> - maps mouse buttons as reported by the VM to ones reported in the events.
  KeyDecodeTable <Dictionary<SmallInteger->SmallInteger>> - maps some keys and their modifiers to other keys (used for instance to map Ctrl-X to Alt-X)
  InterruptSemaphore <Semaphore> - signalled by the the VM and/or the event loop upon receiving an interrupt keystroke.
  InterruptWatcherProcess <Process> - waits on the InterruptSemaphore and then responds as appropriate.
  EventPollPeriod <Integer> - the number of milliseconds to wait between polling for more events in the userInterruptHandler.
  EventTicklerProcess <Process> - the process that makes sure that events are polled for often enough (at least every EventPollPeriod milliseconds).
 
  Event format:
  The current event format is very simple. Each event is recorded into an 8 element array. All events must provide some SmallInteger ID (the first field in the event buffer) and a time stamp (the second field in the event buffer), so that the difference between the time stamp of an event and the current time can be reported.
 
  Currently, the following events are defined:
 
  Null event
  =============
  The Null event is returned when the ST side asks for more events but no more events are available.
  Structure:
  [1] - event type 0
  [2-8] - unused
 
  Mouse event structure
  ==========================
  Mouse events are generated when mouse input is detected.
- Structure:
  [1] - event type 1
  [2] - time stamp
  [3] - mouse x position
  [4] - mouse y position
  [5] - button state; bitfield with the following entries:
+ 1 - 2r001 yellow (e.g., right) button
+ 2 - 2r010 blue (e.g., middle) button
+ 4 - 2r100 red (e.g., left) button
- 1 - yellow (e.g., right) button
- 2 - blue (e.g., middle) button
- 4 - red (e.g., left) button
  [all other bits are currently undefined]
  [6] - modifier keys; bitfield with the following entries:
  1 - shift key
  2 - ctrl key
  4 - (Mac specific) option key
  8 - Cmd/Alt key
  [all other bits are currently undefined]
  [7] - reserved.
  [8] - reserved.
 
  Keyboard events
  ====================
  Keyboard events are generated when keyboard input is detected.
  [1] - event type 2
  [2] - time stamp
+ [3] - character code (Ascii)
+ For now the character code is in Mac Roman encoding. See #macToSqueak.
+ For key press/release (see [4]), character codes are normalized.
- [3] - character code
- For now the character code is in Mac Roman encoding.
  [4] - press state; integer with the following meaning
+ 0 - character (aka. key stroke or key still pressed)
+ 1 - key press (aka. key down)
+ 2 - key release (aka. key up)
- 0 - character
- 1 - key press (down)
- 2 - key release (up)
  [5] - modifier keys (same as in mouse events)
+ For key press/release (see [4]), modifier keys are still accessible.
+ [6] - character code (Unicode UTF32)
+ Manual decoding via KeyboardInputInterpreter possible.
+ For key press/release (see [4]), character codes are normalized.
- [6] - reserved.
  [7] - reserved.
  [8] - reserved.
+
+ Mouse-wheel event structure
+ ==========================
+ Mouse-wheel events are generated when mouse-wheel input is detected.
+ [1] - event type 7
+ [2] - time stamp
+ [3] - horizontal scroll delta
+ [4] - vertical scroll delta
+ [5] - button state (same as in mouse events)
+ [6] - modifier keys (same as in mouse events)
+ [7] - reserved.
+ [8] - reserved.
  !

Item was changed:
  ----- Method: EventSensor class>>installDuplicateKeyEntryFor: (in category 'key decode table') -----
  installDuplicateKeyEntryFor: c
+ "Updates key-decode table. The table maps pairs of {character code . modifier code}. See the class comment for more information."
+
  | key |
  key := c asInteger.
+ self flag: #toDocument. "mt: Why that 'key bitAnd: 16r9F' conversion? Some old VM hack?"
+ KeyDecodeTable at: { key bitAnd: 16r9F . 2 "ctrl" } put: { key . 8 "cmd/alt" }.
+ KeyDecodeTable at: { key . 8 "cmd/alt" } put: { key . 8 "cmd/alt"}
- "first do control->alt key"
- KeyDecodeTable at: { key bitAnd: 16r9F . 2 } put: { key . 8 }.
- "then alt->alt key"
- KeyDecodeTable at: { key . 8 } put: { key . 8 }
  !

Item was changed:
  ----- Method: EventSensor class>>installSwappedKeyEntryFor: (in category 'key decode table') -----
  installSwappedKeyEntryFor: c
+ "Updates key-decode table. The table maps pairs of {character code . modifier code}. See the class comment for more information."
+
  | key |
  key := c asInteger.
+ self flag: #toDocument. "mt: Why that 'key bitAnd: 16r9F' conversion? Some old VM hack?"
+ KeyDecodeTable at: { key bitAnd: 16r9F . 2 "ctrl" } put: { key . 8 "cmd/alt" }.
+ KeyDecodeTable at: { key . 8 "cmd/alt" } put: { key bitAnd: 16r9F . 2 "cmd/alt" }!
- "first do control->alt key"
- KeyDecodeTable at: { key bitAnd: 16r9F . 2 } put: { key . 8 }.
- "then alt->control key"
- KeyDecodeTable at: { key . 8 } put: { key bitAnd: 16r9F . 2 }!