Provide functions to read/write string directly to Arena about bigqueue HOT 5 CLOSED

Hi, I would like to work on this.

from bigqueue.

We have got two choices here -

1. Either we allow type of the queue. A queue could be of type int, string, []byte. This would mean that a queue can store only one type of elements. We store the type of the queue in index and allow only corresponding write functions, disable the rest.
2. In this choice, a queue can have any type of values. The type of the element is decides by the header that we will put into the data file (arena). This may increase storage requirement a bit.

from bigqueue.

I think the first one would be better. If the use case requires information about each member of the queue, then that could be handled later on.

from bigqueue.

One more idea, in this case we stop worrying about the type, and only provide helper functions so that -

• users don't have to worry about serialization and deserialization
• more efficiency, avoids one copy

One will still have to know what typed function to call (i.e. call ReadString or ReadUint64).

For example, for writing, we will have to define following internal interface -

type dataObject interface {
	Len() int
	Write(m mmap.IMmap, offset, from, to int) error
}

Let's say we want to write String into the mapped area, we will define following types -

type stringObject struct {
  s string
}

func (s *stringObject) Len() int {
  return len(s.s)
}

func (s *stringObject) Write(m mmap.IMmap, offset, from, to int) error {
  _, err := m.WriteString(s[from:to], offset) // this function needs to be added to mmap lib
  return err
}

Now, we can implement a generic function that takes an object of type dataObject and write it to mapped area by writing it's length first and then the value, possibly into multiple arenas if necessary.

from bigqueue.

Yeah that seems better

from bigqueue.