res_parking: Replace Parker snapshots with ParkerDialString

This process also involved a large amount of rework regarding how to redial
the Parker when a channel leaves a parking lot due to timeout. An attended
transfer channel variable has been added to attended transfers to extensions
that will eventually park (but haven't at the time of transfer) as well.
This resolves one of the two BUGBUG comments remaining in res_parking.

(issues ASTERISK-21877)
Reported by: Matt Jordan
Review: https://reviewboard.asterisk.org/r/2638/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@393704 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 22 insertions, 6 deletions

diff --git a/CHANGES b/CHANGES
index e6da22224..3223822ba 100644
--- a/CHANGES
+++ b/CHANGES
@@ -136,6 +136,10 @@ Core
    feature on the bridge peer in a multi-party bridge will execute it on all
    peers of the activating channel.
 
+ * A channel variable ATTENDEDTRANSFER is now set which indicates which channel
+   was responsible for an attended transfer in a similar fashion to
+   BLINDTRANSFER.
+
 AMI (Asterisk Manager Interface)
 ------------------
  * The SIPshowpeer action will now include a 'SubscribeContext' field for a peer
@@ -176,12 +180,24 @@ AMI (Asterisk Manager Interface)
 
  * The AMI events 'ParkedCall', 'ParkedCallTimeOut', 'ParkedCallGiveUp', and
    'UnParkedCall' have changed significantly in the new res_parking module.
-   First, channel snapshot data is included for both the parker and the parkee
-   in lieu of the "From" and "Channel" fields. They follow standard channel
-   snapshot format but each field is suffixed with 'Parker' or 'Parkee'
-   depending on which side it applies to. The 'Exten' field is replaced with
-   'ParkingSpace' since the registration of extensions as for parking spaces
-   is no longer mandatory.
+
+   The 'Channel' and 'From' headers are gone. For the channel that was parked
+   or is coming out of parking, a 'Parkee' channel snapshot is issued and it
+   has a number of fields associated with it. The old 'Channel' header relayed
+   the same data as the new 'ParkeeChannel' header.
+
+   The 'From' field was ambiguous and changed meaning depending on the event.
+   for most of these, it was the name of the channel that parked the call
+   (the 'Parker'). There is no longer a header that provides this channel name,
+   however the 'ParkerDialString' will contain a dialstring to redial the
+   device that parked the call.
+
+   On UnParkedCall events, the 'From' header would instead represent the
+   channel responsible for retrieving the parkee. It receives a channel
+   snapshot labeled 'Retriever'. The 'from' field is is replaced with
+   'RetrieverChannel'.
+
+   Lastly, the 'Exten' field has been replaced with 'ParkingSpace'.
 
  * The AMI event 'Parkinglot' (response to 'Parkinglots' command) in a similar
    fashion has changed the field names 'StartExten' and 'StopExten' to