Changes between Version 1 and Version 2 of DynamicCallAnalysis

Timestamp:

Sep 21, 2012, 1:13:12 PM (12 years ago)

Author:

manualwiki

Comment:

--

DynamicCallAnalysis

@@ -45 +45 @@
 ri:clean_dyn().
 }}}
+
+{{{#!comment
+
+== Configurable dynamic function analyzer ==
+
+Dynamic function analyzer was extended to handle user defined functions that has semantics similar to apply BIF.
+
+In Erlang it is sometimes preferable to use custom functions that act as a wrapper for a simple apply. 
+For example for load distribution among different Erlang nodes. Or implementing callback functions.
+
+=== Small example ===
+
+Consider the following small example.
+
+The module which is going to be analyzed.
+{{{#!erlang
+-module(dynfun_example).
+-compile(export_all).
+
+a()->
+    1.
+
+b()->
+    erlang:apply(?MODULE, a, []).
+}}}
+
+The configuration file, which is located at the tool root, and is called {{{dynfunref.conf}}}:
+{{{#!erlang
+{
+{erlang, apply},
+['$1', '$2', '$3'],
+[{'$1', '$2', '$3'}]
+}.
+}}}
+
+The result:
+{{{#!erlang
+(refactorerl@localhost)8> ri:reset().                          
+{ok,[]}
+ok
+(refactorerl@localhost)9> ri:add("/Users/V/erlang/dynfun_766").
+| 1.22 kB/s >>>>>>>>>>>>>>>>>>>| [   4/   4] dynfun_example.erl
+ok
+(refactorerl@localhost)10> ri:q("mods.funs.dyncalls").          
+ok
+(refactorerl@localhost)11> ri:anal_dyn().                       
+Function reference patterns loaded (1, dynfunref.conf)
+
+Analysing local funs... (0 done).                                              
+Collecting function calls...
+1 function calls found in the database.
+Looking for dynamic references...
+1 dynamic function references found.
+Inspecting dynamic references... (1/1)
+1 potential callee successfully spotted.
+Storing dynamic references... (1/1)
+Updating the call graph... (1/1)
+
+Analysis completed.
+ok
+(refactorerl@localhost)12> ri:q("mods.funs.dyncalls").          
+dynfun_example:b/0
+    dynfun_example:a/0
+ok
+}}}
+
+A user-defined references to link from the original function call was made. 
+
+=== How to specify a valid Erlang match specification ===
+{{{#!erlang
+{
+{erlang, apply},       %analyzed module and function
+['$1', '$2', '$3'],    %match
+[{'$1', '$2', '$3'}]   %where to link (an exact function)
+}.
+}}}
+The first element of the tuple is a tuple, which first element is the name of the module in which the analyzed function is located. The name of the function is at the second element. 
+The second element is a list of match specs. Its length equals to the arity of the analyzed function. 
+The third argument is a list of mappings represented by tuples. One element of a mapping is a 3-tuple representing an exact function. The third element is represent arity rather than agrments.
+
+=== Another example ===
+Consider the following 2 module.
+{{{#!erlang
+-module(router).
+-export([route/2]).
+
+route(ReqID, Args)->
+    [Function | Args0] = tuple_to_list(Args),
+    Master =self(),    
+    Worker = fun()->
+        Result = try
+            apply(router_backend, Function, [ReqID]++Args0)
+        catch
+            _ -> error
+        end,
+        Master ! {ReqID, Result}
+        end,
+    spawn(Worker),
+    receive
+         {ReqID, Result} -> Result
+    end.
+    
+ex_call()->
+    route(1, {a}).
+
+ex_call2()->
+    route(2,{b,1}).
+}}}
+
+{{{#!erlang
+-module(router_backend).
+-compile(export_all).
+
+a(_)->
+    2.
+
+b(_,A)->
+    A+1.
+}}}
+
+The configuration file:
+{{{#!erlang
+%will link router_backend:a/1 to router:ex_call/0
+{{router,route},
+['_', {'$1'}],
+[
+    {router_backend, '$1', 1}
+]}.
+
+%will link router_backend:b/2 to router:ex_call2/0
+{{router,route},
+['_', {'$1','_'}],
+[
+    {router_backend, '$1', 2}
+]}.
+}}}
+
+
+The result:
+{{{#!erlang
+(refactorerl@localhost)26> ri:reset().                           
+{ok,[]}
+ok
+(refactorerl@localhost)27> ri:add("/Users/V/erlang/mini_router").
+| 1.12 kB/s >>>>>>>>>>>>>>>>>>>| [   4/   4] router.erl
+| 1.18 kB/s >>>>>>>>>>>>>>>>>>>| [   4/   4] router_backend.erl
+ok
+(refactorerl@localhost)28> ri:anal_dyn().
+Function reference patterns loaded (2, dynfunref.conf)
+
+Analysing local funs... (1 done).                                              
+Collecting function calls...
+6 function calls found in the database.
+Looking for dynamic references...
+5 dynamic function references found.
+Inspecting dynamic references... (5/5)
+3 potential callee successfully spotted.
+Storing dynamic references... (3/3)
+Updating the call graph... (3/3)
+
+Analysis completed.
+ok
+(refactorerl@localhost)29> ri:q("mods.funs.dyncalls").
+router:ex_call/0
+    router_backend:a/1
+router:ex_call2/0
+    router_backend:b/2
+ok
+}}}
+
+A dynamic function reference were made to link {{{router_backend:a/1}}} to {{{router:ex_call/0 }}},
+and to link {{{router_backend:b/2}}} to {{{router:ex_call2/0}}}.
+}}}