The Resource Loan pattern

The Loan pattern, as the  name suggest, loans a resource to a function  In the example given below, a file handle is loaned to consumers of the class. It performs following steps:

1. It creates a resource that you can use (a file handle )
2. It loans the resource (file handle ) to functions  (lambdas) that will use it
3. This function is passed by the caller and executed by the resource holder
4. The resource (file handle ) is closed or destroyed  by the resource holder

 

 

The following code implements the Resource Loan pattern for resource management. The pattern helps to avoid resource leakage when writing code:

//----------- ResourceLoan.cpp 
#include <rxcpp/rx.hpp> 
using namespace std; 
////////////////////////// 
// implementation of Resource Loan  Pattern. The Implementation opens a file 
// and does not pass the file handle to user  defined Lambda. The Ownership remains with 
// the class  
class ResourceLoan { 
   FILE *file;  // This is the resource which is being...