Implement new APIs: LoadCaptcha, RequestCaptcha, and AbortCaptcha.

src/Posting/Captcha.cache.coffee

@@ -1,7 +1,9 @@
 Captcha.cache =
   init: ->
     $.on d, 'SaveCaptcha', (e) =>
-      @save e.detail
+      @saveAPI e.detail
+    $.on d, 'NoCaptcha', (e) =>
+      @noCaptcha e.detail
 
   captchas: []
 
@@ -10,11 +12,16 @@ Captcha.cache =
 
   needed: ->
     not (
-      (/\b_ct=/.test(d.cookie) and QR.posts[0].thread isnt 'new') or @captchas.length or QR.req
+      @haveCookie() or @captchas.length or QR.req
     ) and (
       QR.posts.length > 1 or Conf['Auto-load captcha'] or QR.posts[0].com or QR.posts[0].file
+    ) and (
+      @submitCB or $.event('LoadCaptcha')
     )
 
+  haveCookie: ->
+    /\b_ct=/.test(d.cookie) and QR.posts[0].thread isnt 'new'
+
   getOne: (isReply) ->
     @clear()
     i = @captchas.findIndex((x) -> isReply or !x.challenge?)
@@ -25,7 +32,35 @@ Captcha.cache =
     else
       null
 
+  request: (isReply) ->
+    return if $.event('RequestCaptcha', {isReply})
+    (cb) => @submitCB = cb
+
+  abort: ->
+    if @submitCB
+      delete @submitCB
+      $.event 'AbortCaptcha'
+
+  saveAPI: (captcha) ->
+    if (cb = @submitCB)
+      delete @submitCB
+      cb captcha
+    else
+      @save captcha
+
+  noCaptcha: (detail) ->
+    if (cb = @submitCB)
+      if !@haveCookie() or detail?.error
+        QR.error(detail?.error or 'Failed to retrieve captcha.')
+        QR.captcha.setup(d.activeElement is QR.nodes.status)
+      delete @submitCB
+      cb()
+
   save: (captcha) ->
+    if (cb = @submitCB)
+      @abort()
+      cb captcha
+      return
     @captchas.push captcha
     @captchas.sort (a, b) -> a.timeout - b.timeout
     @count()

src/Posting/QR.coffee

@@ -673,7 +673,7 @@ QR =
       err or= 'Original comment required.'
 
     if QR.captcha.isEnabled and !(/\b_ct=/.test(d.cookie) and threadID) and !err
-      captcha = QR.captcha.getOne(!!threadID)
+      captcha = QR.captcha.getOne(!!threadID) or Captcha.cache.request(!!threadID)
       unless captcha
         err = 'No valid captcha.'
         QR.captcha.setup(!QR.cooldown.auto or d.activeElement is QR.nodes.status)
@@ -736,9 +736,14 @@ QR =
       # Wait for captcha to be verified before submitting post.
       QR.req =
         progress: '...'
-        abort: -> cb = null
+        abort: ->
+          Captcha.cache.abort()
+          cb = null
       captcha (response) ->
-        if response
+        if Captcha.cache.haveCookie()
+          cb?()
+          Captcha.cache.save response if response
+        else if response
           cb? response
         else
           delete QR.req

src/platform/$.coffee

@@ -340,7 +340,7 @@ $.event = (event, detail, root=d) ->
   if detail? and typeof cloneInto is 'function'
     detail = cloneInto detail, d.defaultView
   <% } %>
-  root.dispatchEvent new CustomEvent event, {bubbles: true, detail}
+  root.dispatchEvent new CustomEvent event, {bubbles: true, cancelable: true, detail}
 
 <% if (type === 'userscript') { %>
 # XXX Make $.event work in Pale Moon with GM 3.x (no cloneInto function).
@@ -361,7 +361,7 @@ do ->
       else
         obj
     $.event = (event, detail, root=d) ->
-      root.dispatchEvent new CustomEvent event, {bubbles: true, detail: clone detail}
+      root.dispatchEvent new CustomEvent event, {bubbles: true, cancelable: true, detail: clone detail}
 <% } %>
 
 $.modifiedClick = (e) ->