Add CChain object for headers-only chain #10894

pull jonasschnelli wants to merge 1 commits into bitcoin:master from jonasschnelli:2017/07/hdr_chain changing 4 files +14 −2

jonasschnelli commented at 1:57 PM on July 21, 2017: contributor

This PR introduces a CChain object for the headers chain. It allows to better inspect the headers chain (things like reorg detection). It would simplify a lot of things for a possible light client (SPV) mode.

Slightly improves the headers-chain fork reporting in getchaintips.
Add CChain object for headers-only chain 890c935d18
jonasschnelli added the label Block storage on Jul 21, 2017
jonasschnelli added this to the "In progress" column in a project

in src/validation.cpp:2617 in 890c935d18

2613 | @@ -2613,7 +2614,10 @@ static CBlockIndex* AddToBlockIndex(const CBlockHeader& block)
2614 |      pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + GetBlockProof(*pindexNew);
2615 |      pindexNew->RaiseValidity(BLOCK_VALID_TREE);
2616 |      if (pindexBestHeader == NULL || pindexBestHeader->nChainWork < pindexNew->nChainWork)
2617 | +    {

meshcollider commented at 7:52 PM on July 21, 2017:

Nit, brace on new line

in src/validation.cpp:3490 in 890c935d18

3486 | @@ -3483,7 +3487,10 @@ bool static LoadBlockIndexDB(const CChainParams& chainparams)
3487 |          if (pindex->pprev)
3488 |              pindex->BuildSkip();
3489 |          if (pindex->IsValid(BLOCK_VALID_TREE) && (pindexBestHeader == NULL || CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
3490 | +        {

meshcollider commented at 7:52 PM on July 21, 2017:

Same here

meshcollider commented at 7:53 PM on July 21, 2017: contributor

utACK https://github.com/bitcoin/bitcoin/commit/890c935d187401dc9e95f2a2c992a5aec4f438ad Couple of nits
sipa commented at 8:00 PM on July 21, 2017: member

It is unnecessary to add a new CChain object (3.5 MiB of RAM) for this. You can test whether pindex is an ancestor of pindexBestHeader using 'pindexBestHeader->GetAncestor(pindex->nHeight) == pindex`.
jonasschnelli commented at 7:16 AM on July 24, 2017: contributor

@sipa: For the light client headers based fork detection the FindFork() method would be very handy. Maybe have a look at the "sketch" SPV code for the wallet: https://github.com/bitcoin/bitcoin/pull/9483/files#diff-b2bb174788c7409b671c46ccc86034bdR1182
jonasschnelli commented at 7:17 AM on July 24, 2017: contributor

If one runs in full non validation mode (light client mode), the memory consumption would be ~the same, because only the headers chain will require memory (the chainActive will be empty).
sipa commented at 7:47 AM on July 24, 2017: member

@jonasschnelli You can use FindCommonAncestor between two CBlockIndex objects if you don't have a CChain, instead of FindFork.
jonasschnelli commented at 8:41 AM on July 24, 2017: contributor

Thanks @sipa. Makes sense. Closing for now.
jonasschnelli closed this on Jul 24, 2017
danra commented at 3:25 PM on September 30, 2017: contributor

@jonasschnelli @sipa If this is no longer relevant I suggest removing it from the "Client-Mode (SPV)" project to reduce noise (especially since there are already two other, somewhat overlapping, PRs in the project)
jonasschnelli removed this from the "In progress" column in a project

DrahtBot locked this on Sep 8, 2021

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