cap max msg size to min(max_int, max_uint32)

[lyuxuan]

No description provided.

[dfawley]

For clarity, how about this:

maxInt := int(^uint(0) >> 1) // the maximum signed integer value on this system
res = min(res, &maxInt)

(Note that your version has an extra pair of parentheses which is hard to see because of all the nesting.)

Why does min() take pointers? That just complicates things further. maxInt could and should be a const instead.

How about make min() and get*MaxSize() take and return ints, and deal with pointers only where you call them:

c.maxSendMessageSize = newInt(getMaxSize(*mc.MaxReqSize, *c.maxSendMessageSize, defaultClientMaxSendMessageSize))

[lyuxuan]

I agree that we should make maxInt const.

getMaxSize was created to handle pointers to avoid dealing with nil condition in caller. It hides the complexity from caller. And min() is just to keep logic simple as we don't need to convert int to *int when returned from it. Probably we should rename these two functions to avoid future confusions (like the input and output are all pointer type)? They are created very specifically for service config and not intended for general usage.

[dfawley]

How about this:

• Change callInfo.max*MessageSize to non-pointer types, since they must always be set. This removes some paranoid checking
• Change min() to accept and return int instead of *int
• Change get[Raw]MaxSize to return ints instead of *ints

Is that possible? I think this would make things simpler and keep getMaxSize able to handle *int inputs.

[lyuxuan]

I don't think we can. callInfo.max*MessageSize is a pointer type because it will be used to receive the value set by user API MaxCall*MsgSize when we configure the call. And we need nil value to indicate that user doesn't set it. And then during invoke, we will reassign its value based on service config value, its current value and default value.

[dfawley]

OK.. well let's just make min deal with ints then? We can deal with the pointers where it's called. Then we can have a const for maxInt and use it without creating memory.

Let's make sure we add some comments on these CallOptions/ServerOptions that specify the maximum effective value is MaxUint32 due to protocol limitations.

[lyuxuan]

fix #1590

[dfawley]

Rolled back by #1619