[snmp|agent] Add the default get-mechanism module snmpa_get

Added the snmpa_get module as the default get-mechanism
for the agent.
This has been done by simply moving the do_get, do_get_next
and do_get_bulk functions from the snmpa_agent module.
Some functions where also moved into the lib module (with
the idea of beeing more generally useful).

OTP-15691

1 files changed, 22 insertions, 5 deletions

diff --git a/lib/snmp/src/agent/snmpa_get_mechanism.erl b/lib/snmp/src/agent/snmpa_get_mechanism.erl
index 1a2133778e..7be4ae79a2 100644
--- a/lib/snmp/src/agent/snmpa_get_mechanism.erl
+++ b/lib/snmp/src/agent/snmpa_get_mechanism.erl
@@ -24,28 +24,45 @@
 %% This module defines the behaviour for the undocumented (hidden)
 %% get-mechanism feature. This allows for implementing your own
 %% handling of get, get-next and get-bulk requests.
-%% Probably only useful for special cases (optimization).
+%% Probably only useful for special cases (e.g. optimization).
 %%
 
 
 
-%% ----------- do_get/3 -----------------------------------------------------
+%% ----------- do_get/2,3 -----------------------------------------------------
+
+%% Purpose: Handles all VBs in a request that is inside the 
+%%          mibview (local).
+
+-callback do_get(UnsortedVBs    :: [snmp:varbind()],
+                 IsNotification :: boolean()) ->
+    {noError, 0, ResVBs :: [snmp:varbind()]} |
+    {ErrStatus :: snmp:error_status(), ErrIndex :: snmp:error_index(), []}.
+
+
+%% Purpose: Handles "get-requests".
 
 -callback do_get(MibView        :: snmp_view_based_acm_mib:mibview(), 
-                 VBs            :: [snmp:varbind()],
+                 UnsortedVBs    :: [snmp:varbind()],
                  IsNotification :: boolean()) ->
     {noError, 0, ResVBs :: [snmp:varbind()]} |
     {ErrStatus :: snmp:error_status(), ErrIndex :: snmp:error_index(), []}.
 
 
+
+
 %% ----------- do_get_next/2 ------------------------------------------------
 
--callback do_get_next(MibView :: snmp_view_based_acm_mib:mibview(),
-                      VBs     :: [snmp:varbind()]) ->
+%% Purpose: Handles "get-next-requests".
+
+-callback do_get_next(MibView     :: snmp_view_based_acm_mib:mibview(),
+                      UnsortedVBs :: [snmp:varbind()]) ->
     {noError, 0, ResVBs :: [snmp:varbind()]} |
     {ErrStatus :: snmp:error_status(), ErrIndex :: snmp:error_index(), []}.
 
 
+
+
 %% ----------- do_get_bulk/6 ------------------------------------------------
 
 -callback do_get_bulk(MibView        :: snmp_view_based_acm_mib:mibview(),