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7392 :: How to implement a RwLock lock

• adnan (orginal) [2021-01-16T08:45:59+01:00] view original

  Hello Nim gurus. I would like to implement something akin to RwLock (https://doc.rust-lang.org/std/sync/struct.RwLock.html) in Nim. Currently, I use a separate Lock, and use the shared data inside a withLock block.

  var dataLock*: Lock
  initLock(dataLock)
  var data*: AppData
  # ...
  withLock dataLock: do(something(data))
  Run

  However,

  1. I need to manually remember to use the dataLock before using data. I would like to get a compilation error if I forget to do so.
  2. I guess I can manually create a type and implement all the methods in a way that all the data is mutated behind the lock but this is (probably) similar to a Mutex, while I would like a RwLock.

  Is there any package that already provides this?

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• QMaster (orginal) [2021-01-16T10:00:12+01:00] view original

  The first item might be implemented like this:

  type DataWithLock = object
    dataLock*: Lock
    data* {.guard: dataLock.}: AppData
  Run

  I'm not sure that guard will work without type definition, but it might.(never did so myself) It will compile with --threads:on only and will warn you if you are accessing to data without locking.

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