Running a Command Conditionally in a CommandList

A structure for conditional_information contains the reasons for conditional values. The software reason and hardware reason will be defined by an enum and will have a special value. This special value will mean that the command is unconditional on that ‘reason’.

1. 
   STRUCT SSM_START_PROCESS_INFO struct in a resource file initiates the process as shown in the code snippet:

   
   STRUCT SSM_START_PROCESS_INFO                     // For starting processes
   {
       WORD type = EStartupProcess;                  // Must not be changed
       LTEXT path = "";                              // Value required
       LTEXT args = "";                              // Passed to the command line of the started process
       WORD start_method = EFireAndForget;           // Can also be EWaitForStart or EDeferredWaitForStart
       LONG timeout = 0;                             // In milliseconds, only used for EWaitForStart
       WORD fail_on_error = EPanicOnCommandFailure;  // Can be EIgnoreCommandFailure
       WORD no_of_retries_on_failure = 0;            // Only used for EWaitForStart
       LLINK conditional_information = 0;            // By default, commands are unconditional
   }

2. 
   Set the LLINK conditional_information parameter to any value.
   1. 
      If LLINK conditional_information is 0, then the resource file reader adds the command to the CommandList.
   2. 
      If LLINK conditional_information is nonzero, then the resource file reader reads the resource which points to a HBufC, and calls a callback function provided by the policy.
3. 
   A callback function is passed to the resource file reader by the policy plug-in calls the resource-file reader. The function that is called has a prototype similar to:

   TBool ConditionalCommandAllowedL( HBufC* information );

   If the return value of this function is true then the command is added to the command list by the resource file reader, else it is discarded.