waddrmgr: optimize using each style functions

[tuxcanfly]

refs #215

WIP: Trying out the approach by replacing AllAccounts with a each style func first.

[davecgh]

This looks like the discussed approach. However, unless we plan to add the ability to allow inactive accounts (which I don't really currently foresee), the name should probably be ForEachAccount instead of ForEachActiveAccount.

EDIT: Addresses, on the other hand, are definitely intended to be active/inactive, so naming that ForEachActiveAddress makes sense.

[tuxcanfly]

Cool, let me correct the func names.

[davecgh]

Looks good. I know there are more coming, so I won't merge it until everything is done.

[tuxcanfly]

Thanks, will be working on the remaining funcs.

[tuxcanfly]

Updated the remaining funcs. Working on optimizing storage for active/inactive addresses as discussed.

[tuxcanfly]

Refactored to store all active addresses in a bucket and use it as an index while iterating over active addresses.

Added upgrade path for migrating from used bucket to active bucket. Running some checks, will be up for review in a bit.

[tuxcanfly]

To avoid confusion, we should stick to differentiating active/inactive addresses. I've replaced all references to used with inactive.

[tuxcanfly]

OK, ready for review. @davecgh

[tuxcanfly]

Also renamed a few methods for consistency e.g AddrAccount to AddressAccount

[tuxcanfly]

Depends on #238 in the way we will treat used addresses since this PR rewoks active/inactive (used) addrs in addition to each-style functions.

[tuxcanfly]

As discussed on IRC, an address can expire after a duration and become inactive while still remaining unused. Therefore, instead of assuming that addr not present in active bucket is used, we should have an explicit db flag on address row using a flag field which determines whether the address is used or not. Similarly, the address should be marked expired after a certain configurable duration.

[tuxcanfly]

Limiting this PR to ForEach implementations, created #254 for implementing active/inactive addresses, which I'll be working on.

[jrick]

This throws away the error and re-assigns the possibly true used value instead of breaking out of the loop and returning true to the caller.

[jrick]

ActiveAccountAddresses wasn't switched over to the new style and I'd like to see some more details in each function comments about how it executes the passed function on each item, breaking early is an error is returned. Just saying "it iterates over X" isn't descriptive enough.

[tuxcanfly]

Moved ActiveAccountAddresses to ForEachActiveAccountAddress and updated the docs to be more descriptive. Fixed AccountUsed to break out and return true on first used addr.

[jrick]

All of the calls to maybeConvertDbError will mangle the break error. I think that errors from this package should be converted, but errors from a caller's callback should not be.

[tuxcanfly]

Thanks, as discussed, I've added a global err Break to signal a early exit from the callback. Please review.

[jrick]

ok

[tuxcanfly]

Thanks