It's not pretty, but if you absolutely must write this code and can't refactor
it, you can always use a closure to scope the defer:
lock1.Lock()
err = func() error {
defer lock1.Unlock()
return performOperation1()
}()
if err != nil {
return err
}
performExpensiveOperation2()
On Fri, Feb 8, 2019, at 18:28, vincent163 wrote:
> I am thinking about how to write programs like this:
> `
> lock1.Lock()
> err = performOperation1()
> if err != nil {
> lock1.Unlock()
> return err
> }
> lock1.Unlock()
> performExpensiveOperation2()
> `
>
> The lock1 must be locked while performing operation1, and I need to use
> its result to perform operation2. Since operation2 is expensive, I
> don't want to hold the lock while performing it, and lock1.Unlock()
> needs to be called before calling operation2.
> Go's defer mechanism doesn't seem to handle this case well since the
> resource is used only within a block and not throughout the function.
> Is there a recommended way to write programs in this case?
> I know I could wrap the lock block in a closure, but that creates a
> completely new scope, so I can't return directly or break out of a loop
> within the closure, etc.
>
>
>
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