proc_lib:spawn相关源码分析

proc_lib中所有关于进程相关的方法都是在bif里的spawn相关方法上封装实现的。主要做进程字典'$ancestors' '$initial_call'的初始化和crash报告、退出处理。

一、proc_lib:spawn*相关函数实现

1、proc_lib:spawn* 相关函数通过调用相应的erlang:spawn*方法，执行proc_lib:init_p方法实现。

2、proc_lib_init_p进行'$ancestors' '$initial_call'进程字典初始化，并执行进程要执行的方法,如果执行异常，则执行proc_lib:exit_p处理异常，做crash报告，并执行exit退出。

-specinit_p(pid(), [pid()], function())->term().

init_p(Parent,Ancestors,Fun)whenis_function(Fun)->

    put('$ancestors', [Parent|Ancestors]),

    {module,Mod} = erlang:fun_info(Fun, module),

    {name,Name} = erlang:fun_info(Fun, name),

    {arity,Arity} = erlang:fun_info(Fun, arity),

    put('$initial_call', {Mod,Name,Arity}),

   try

        Fun()

   catch

        Class:Reason->

            exit_p(Class,Reason)

   end.

-specinit_p(pid(), [pid()], atom(), atom(), [term()])->term().

init_p(Parent,Ancestors,M,F,A)whenis_atom(M), is_atom(F), is_list(A)->

    put('$ancestors', [Parent|Ancestors]),

    put('$initial_call', trans_init(M,F,A)),

    init_p_do_apply(M,F,A).

init_p_do_apply(M,F,A)->

   try

        apply(M,F,A)

   catch

        Class:Reason->

            exit_p(Class,Reason)

   end.

exit_p(Class,Reason)->

   caseget('$initial_call')of

        {M,F,A}whenis_atom(M), is_atom(F), is_integer(A)->

           MFA= {M,F,make_dummy_args(A, [])},

            crash_report(Class,Reason,MFA),

            exit(Reason);

        _->

           %% The process dictionary has been cleared or

           %% possibly modified.

            crash_report(Class,Reason, []),

            exit(Reason)

   end.

二、proc_lib:start*相关函数实现

1、proc_lib:start*相关函数通过调用proc_lib:spawn*相关方法实现进程创建，然后调用proc_lib:sync_wait等待ack消息，实现同步。

sync_wait(Pid,Timeout)->

   receive

        {ack,Pid,Return}->

           Return;

        {'EXIT',Pid,Reason}->

            {error,Reason}

   afterTimeout->

            unlink(Pid),

            exit(Pid, kill),

            flush(Pid),

            {error, timeout}

   end.

-specflush(pid())->'true'.

flush(Pid)->

   receive

        {'EXIT',Pid,_}->

            true

   after0->

            true

   end.