[asterisk-dev] [Code Review] Channel Hangup Handlers

[rmudgett]

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Since this is another type of 'h' exten, these handlers should get run in the same places in the code as the 'h' exten: ast_bridge_call() and __ast_pbx_run().

Some consideration will need to be made for what happens if the hangup handlers run but the 'h' exten doesn't exit when the bridge is broken.
An AST_FLAG_BRIDGE_H_HANDLERS_RUN flag like AST_FLAG_BRIDGE_HANGUP_RUN is going to be needed.

- rmudgett


On May 24, 2011, 4:09 p.m., kobaz wrote:
> 
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> This is an automatically generated e-mail. To reply, visit:
> https://reviewboard.asterisk.org/r/1230/
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> 
> (Updated May 24, 2011, 4:09 p.m.)
> 
> 
> Review request for Asterisk Developers.
> 
> 
> Summary
> -------
> 
> This is the hangup handler patch, and associated 
> helper function ast_pbx_exten_parse(), which I think is needed to 
> separate the functionality of parsing a gosub target from actually going 
> to the target.  It's been malloc debugged and valgrind debugged and tested
> for several months in production environments.
> 
> Overview of module:
> I find the 'h' extensions to be limited, cumbersome, and error prone 
> when writing very complex dialplan, especially when using lots of gotos 
> and gosubs.  Say you have a main dialplan entry point context called 
> callqueue.  If at any point after callqueue runs, you want to run a 
> hangup handler specific for the callqueue dialplan, you have to put an 
> 'h' extension in every single context you plan to possibly jump to after 
> entering callqueue.  This solves that problem, and gives the added 
> benefit of cascading hangup handlers.
> 
> For proof of concept development convenience, I used an existing 
> function for setting up the hangup handlers, but it should probably be 
> it's own function
> 
> Cascading hangup handlers are also possible, where as with standard 
> dialplan h extensions, they are not:
> 
> context test {
>    s => {
>      goto fooTest, s, 1;
>    }
> }
> 
> context fooTest {
>    s => {
>      GoSub(barTest,s,1);
>    }
> 
>    h => {
>      NoOp(footest hangup);
>    }
> }
> 
> context barTest {
>    s => {
>      NoOp(something in bar);
>      Hangup();
>    }
> 
>    h => {
>      NoOp(bartest hangup);
>    }
> }
> 
> Execution:
>      -- Goto (fooTest,s,1)
>      -- Executing [s at fooTest:1] Gosub("SIP/tipton-local-0000000b", 
> "barTest,s,1") in new stack
>      -- Executing [s at barTest:1] NoOp("SIP/tipton-local-0000000b", 
> "something in bar") in new stack
>      -- Executing [s at barTest:2] Hangup("SIP/tipton-local-0000000b", "") 
> in new stack
>    == Spawn extension (barTest, s, 2) exited non-zero on 
> 'SIP/intellasoft-tipton-local-0000000b'
>      -- Executing [h at barTest:1] NoOp("SIP/tipton-local-0000000b", 
> "bartest hangup") in new stack
> 
> Only the deepest 'h' exten will execute
> 
> 
> Where as with this new method, you could call addhanguphandler as many 
> times as you like, and they will all execute in the order of most 
> recently added will execute first.
> 
> Cascading hangup handlers:
> Set(CHANNEL(addhanguphandler)="callqueueHangupHandler,s,1");
> Set(CHANNEL(addhanguphandler)="someotherHangupHandler,s,1");
> Set(CHANNEL(addhanguphandler)="yetanotherHangupHandler,s,1");
> 
> **NOTE**: I have had nasty deadlock problems (as you can see a bunch of locking is commented out, but it works nonetheless (scary))
> Maybe someone can help me with the locking.
> 
> 
> Diffs
> -----
> 
>   trunk/funcs/func_channel.c 320708 
>   trunk/include/asterisk/channel.h 320708 
>   trunk/include/asterisk/pbx.h 320708 
>   trunk/main/channel.c 320708 
>   trunk/main/cli.c 320708 
>   trunk/main/pbx.c 320708 
> 
> Diff: https://reviewboard.asterisk.org/r/1230/diff
> 
> 
> Testing
> -------
> 
> Usage:
> context callqueueHangupHandler {
>    s => {
>      // cleanup here
>    }
> }
> 
> context callqueue {
>    s => {
>      Set(CHANNEL(addhanguphandler)="callqueueHangupHandler,s,1");
>      gosub(foo...)
>      goto bar..;
>    }
> }
> 
> Execution:
> 1. callqueue: set(channel(addhanguphandler...)
> 2. gosub
> 3. goto bar
> 4. channel hangs up
> 5. channel launches dialplan @callqueueHangupHandler
> 
> 
> Thanks,
> 
> kobaz
> 
>

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