enterNormalMode; new command - implementation

Here's the problem...

Many sites define their own keyboard shortcuts, for example Google Play
Music defines `gh` for "go home".

On such sites, it's natural to set up pass keys for `g` and `h`.

But that makes any Vimium key bindings which begin with `g`
inaccessible.

Here, we add a new command `enterNormalMode` which installs a new
normal-mode instance (without any pass keys).  This executes a single
normal-mode command then exits.

Example:

    map \ enterNormalMode
    map | enterNormalMode count=999999

Assuming `g` and `o` are pass keys:

- `gh` or `o` - use the page's binding
- `\gg` - scroll to top
- `2\ggo` - scroll to the top and open the Vomnibar
- `\g<Escape>o` - open the Vomnibar
- `\<Escape>o` - use the page's bindings
- `\\\\\\<Escape>o` - use the page's bindings (new normal-mode instances
  displace previous ones)

This required some changes to the scroller.  Previously, we only ever
had one normal-mode instance, and could arrange statically that the
scroller's key listeners were above normal-mode's key listeners in the
handler stack.  Here, we fix this by adding and removing the scroller's
listeners dynamically, so they're always at the top of the handler
stack.

6 files changed, 43 insertions, 18 deletions

diff --git a/content_scripts/mode.coffee b/content_scripts/mode.coffee
index 6508627e..c1dea59a 100644
--- a/content_scripts/mode.coffee
+++ b/content_scripts/mode.coffee
@@ -81,9 +81,8 @@ class Mode
         _name: "mode-#{@id}/exitOnEscape"
         "keydown": (event) =>
           return @continueBubbling unless KeyboardUtils.isEscape event
-          DomUtils.suppressKeyupAfterEscape handlerStack
           @exit event, event.srcElement
-          @suppressEvent
+          DomUtils.suppressKeyupAfterEscape handlerStack
 
     # If @options.exitOnBlur is truthy, then it should be an element.  The mode will exit when that element
     # loses the focus.
diff --git a/content_scripts/mode_find.coffee b/content_scripts/mode_find.coffee
index 8621edf8..0178527b 100644
--- a/content_scripts/mode_find.coffee
+++ b/content_scripts/mode_find.coffee
@@ -47,9 +47,8 @@ class PostFindMode extends SuppressPrintable
       _name: "mode-#{@id}/handle-escape"
       keydown: (event) =>
         if KeyboardUtils.isEscape event
-          DomUtils.suppressKeyupAfterEscape handlerStack
           @exit()
-          @suppressEvent
+          DomUtils.suppressKeyupAfterEscape handlerStack
         else
           handlerStack.remove()
           @continueBubbling
diff --git a/content_scripts/mode_insert.coffee b/content_scripts/mode_insert.coffee
index 4cb0a39e..d5d98297 100644
--- a/content_scripts/mode_insert.coffee
+++ b/content_scripts/mode_insert.coffee
@@ -17,7 +17,6 @@ class InsertMode extends Mode
         return @suppressEvent
 
       return @passEventToPage unless event.type == 'keydown' and KeyboardUtils.isEscape event
-      DomUtils.suppressKeyupAfterEscape handlerStack
       target = event.srcElement
       if target and DomUtils.isFocusable target
         # Remove the focus, so the user can't just get back into insert mode by typing in the same input box.
@@ -26,7 +25,7 @@ class InsertMode extends Mode
         # An editable element in a shadow DOM is focused; blur it.
         @insertModeLock.blur()
       @exit event, event.srcElement
-      @suppressEvent
+      DomUtils.suppressKeyupAfterEscape handlerStack
 
     defaults =
       name: "insert"
diff --git a/content_scripts/mode_key_handler.coffee b/content_scripts/mode_key_handler.coffee
index 480a79af..9b5a1fef 100644
--- a/content_scripts/mode_key_handler.coffee
+++ b/content_scripts/mode_key_handler.coffee
@@ -36,6 +36,18 @@ class KeyHandlerMode extends Mode
     @mapKeyRegistry = {}
     Utils.monitorChromeStorage "mapKeyRegistry", (value) => @mapKeyRegistry = value
 
+    if options.exitOnEscape
+      # If we're part way through a command's key sequence, then a first Escape should reset the key state,
+      # and only a second Escape should actually exit this mode.
+      @push
+        _name: "key-handler-escape-listener"
+        keydown: (event) =>
+          if KeyboardUtils.isEscape(event) and not @isInResetState()
+            @reset()
+            DomUtils.suppressKeyupAfterEscape handlerStack
+          else
+            @continueBubbling
+
   onKeydown: (event) ->
     keyChar = KeyboardUtils.getKeyCharString event
     keyChar = @mapKeyRegistry[keyChar] ? keyChar
@@ -92,7 +104,10 @@ class KeyHandlerMode extends Mode
   # Keystrokes are *never* considered pass keys if the user has begun entering a command.  So, for example, if
   # 't' is a passKey, then the "t"-s of 'gt' and '99t' are neverthless handled as regular keys.
   isPassKey: (keyChar) ->
-    @countPrefix == 0 and @keyState.length == 1 and keyChar in (@passKeys ? "")
+    @isInResetState() and keyChar in (@passKeys ? "")
+
+  isInResetState: ->
+    @countPrefix == 0 and @keyState.length == 1
 
   handleKeyChar: (keyChar) ->
     bgLog "handle key #{keyChar} (#{@name})"
@@ -106,6 +121,7 @@ class KeyHandlerMode extends Mode
       bgLog "  invoke #{command.command} count=#{count} "
       @reset()
       @commandHandler {command, count}
+      @exit() if @options.count? and --@options.count <= 0
     @suppressEvent
 
 root = exports ? window
diff --git a/content_scripts/scroller.coffee b/content_scripts/scroller.coffee
index 3a1b3772..a533c161 100644
--- a/content_scripts/scroller.coffee
+++ b/content_scripts/scroller.coffee
@@ -128,13 +128,15 @@ checkVisibility = (element) ->
 CoreScroller =
   init: ->
     @time = 0
-    @lastEvent = null
-    @keyIsDown = false
+    @lastEvent = @keyIsDown = @cancelEventListenerId = null
 
+  # This installs listeners for events which should cancel smooth scrolling.
+  installCanceEventListener: ->
+    @removeCancelEventListener()
     # NOTE(smblott) With extreme keyboard configurations, Chrome sometimes does not get a keyup event for
     # every keydown, in which case tapping "j" scrolls indefinitely.  This appears to be a Chrome/OS/XOrg bug
     # of some kind.  See #1549.
-    handlerStack.push
+    @cancelEventListenerId = handlerStack.push
       _name: 'scroller/track-key-status'
       keydown: (event) =>
         handlerStack.alwaysContinueBubbling =>
@@ -149,6 +151,10 @@ CoreScroller =
         handlerStack.alwaysContinueBubbling =>
           @time += 1 if event.target == window
 
+  removeCancelEventListener: ->
+    handlerStack.remove @cancelEventListenerId if @cancelEventListenerId?
+    @cancelEventListenerId = @lastEvent = @keyIsDown = null
+
   # Return true if CoreScroller would not initiate a new scroll right now.
   wouldNotInitiateScroll: -> @lastEvent?.repeat and Settings.get "smoothScroll"
 
@@ -175,7 +181,7 @@ CoreScroller =
     return if @lastEvent?.repeat
 
     activationTime = ++@time
-    myKeyIsStillDown = => @time == activationTime and @keyIsDown
+    myKeyIsStillDown = => @time == activationTime and @keyIsDown ? true
 
     # Store amount's sign and make amount positive; the arithmetic is clearer when amount is positive.
     sign = getSign amount
@@ -215,13 +221,15 @@ CoreScroller =
         requestAnimationFrame animate
       else
         # We're done.
+        @removeCancelEventListener()
         checkVisibility element
 
     # If we've been asked not to be continuous, then we advance time, so the myKeyIsStillDown test always
     # fails.
     ++@time unless continuous
 
-    # Launch animator.
+    # Start scrolling.
+    @installCanceEventListener()
     requestAnimationFrame animate
 
 # Scroller contains the two main scroll functions which are used by clients.
diff --git a/content_scripts/vimium_frontend.coffee b/content_scripts/vimium_frontend.coffee
index fcca98ab..64e13852 100644
--- a/content_scripts/vimium_frontend.coffee
+++ b/content_scripts/vimium_frontend.coffee
@@ -111,11 +111,13 @@ handlerStack.push
 
 class NormalMode extends KeyHandlerMode
   constructor: (options = {}) ->
-    super extend options,
+    defaults =
       name: "normal"
-      indicator: false # There is no mode indicator in normal mode.
+      indicator: false # There is normally no mode indicator in normal mode.
       commandHandler: @commandHandler.bind this
 
+    super extend defaults, options
+
     chrome.storage.local.get "normalModeKeyStateMapping", (items) =>
       @setKeyMapping items.normalModeKeyStateMapping
 
@@ -123,10 +125,6 @@ class NormalMode extends KeyHandlerMode
       if area == "local" and changes.normalModeKeyStateMapping?.newValue
         @setKeyMapping changes.normalModeKeyStateMapping.newValue
 
-    # Initialize components which normal mode depends upon.
-    Scroller.init()
-    FindModeHistory.init()
-
   commandHandler: ({command: registryEntry, count}) ->
     count *= registryEntry.options.count ? 1
     count = 1 if registryEntry.noRepeat
@@ -150,6 +148,9 @@ installModes = ->
   # Install the permanent modes. The permanently-installed insert mode tracks focus/blur events, and
   # activates/deactivates itself accordingly.
   normalMode = new NormalMode
+  # Initialize components upon which normal mode depends.
+  Scroller.init()
+  FindModeHistory.init()
   new InsertMode permanent: true
   new GrabBackFocus if isEnabledForUrl
   normalMode # Return the normalMode object (for the tests).
@@ -386,6 +387,9 @@ extend window,
   passNextKey: (count) ->
     new PassNextKeyMode count
 
+  enterNormalMode: (count) ->
+    new NormalMode exitOnEscape: true, indicator: "Normal mode", count: count, singleton: "enterNormalMode"
+
   focusInput: do ->
     # Track the most recently focused input element.
     recentlyFocusedElement = null