Using inner classes to simplify complex cleanup in C++ (code)
by at 5:55 PM
A lot of my work involves writing C++ code which uses fairly low-level C APIs which require stateful initialization and cleanup at various points (for example, binding a resource, performing an operation, and then unbinding the resource when it's done). The usual approach to this sort of thing is like this:
This is a bit annoying to deal with, especially if the unbind procedure is fairly complex. What's even worse is if you have multiple resources which get bound and need to be unbound, especially if there are multiple steps between those resource bindings. So here is a way to simplify this sort of thing.
bool MyClass::useResource() {
if (bindResource(mResource) != RESULT_OK) {
//! Binding failed; return failure
return false;
}
if (doSomethingComplex() != RESULT_OK) {
//! Our complex operation failed; return failure (but first unbind the resource)
unbindResource(mResource);
return false;
}
if (doSomethingElse() != RESULT_OK) {
//! Another complex operation failed; return failure (but first unbind the resource)
unbindResource(mResource);
return false;
}
// We were successful; unbind the resource and return success
unbindResource(mResource);
return true;
}
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