This change introduces garbage collection for the light client. Historical
chain data is deleted periodically. If you want to disable the GC, use
the --light.nopruning flag.

This adds a new API method on core.BlockChain to allow interrupting
running data inserts, and calls the method before shutting down the
downloader.

The BlockChain interrupt checks are now done through a method instead
of inlining the atomic load everywhere. There is no loss of efficiency from
this and it makes the interrupt protocol a lot clearer because the check is
defined next to the method that sets the flag.

* cmd, core, eth: init tx lookup in background

* core/rawdb: tiny log fixes to make it clearer what's happening

* core, eth: fix rebase errors

* core/rawdb: make reindexing less generic, but more optimal

* rlp: implement rlp list iterator

* core/rawdb: new implementation of tx indexing/unindex using generic tx iterator and hashing rlp-data

* core/rawdb, cmd/utils: fix review concerns

* cmd/utils: fix merge issue

* core/rawdb: add some log formatting polishes

Co-authored-by: rjl493456442 <garyrong0905@gmail.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>

* all: seperate consensus error and evm internal error

There are actually two types of error will be returned when
a tranaction/message call is executed: (a) consensus error
(b) evm internal error. The former should be converted to
a consensus issue, e.g. The sender doesn't enough asset to
purchase the gas it specifies. The latter is allowed since
evm itself is a blackbox and internal error is allowed to happen.

This PR emphasizes the difference by introducing a executionResult
structure. The evm error is embedded inside. So if any error
returned, it indicates consensus issue happens.

And also this PR improve the `EstimateGas` API to return the concrete
revert reason if the transaction always fails

* all: polish

* accounts/abi/bind/backends: add tests

* accounts/abi/bind/backends, internal: cleanup error message

* all: address comments

* core: fix lint

* accounts, core, eth, internal: address comments

* accounts, internal: resolve revert reason if possible

* accounts, internal: address comments

* core: write chain data in atomic way

* core, light: address comments

* core, light: fix linter

* core, light: address comments

Also fix the input formatter on clique_getSnapshot and clique_getSigners
so that integers as well as hex number strings are accepted.

* les: loose restriction of unit tests

* les: update unit tests

* les, light: slim the unit tests

This change adds support for EIP-1898. 

* les: detailed relative cost metrics

* les: filter txpool relative request statistic

* les: initialize price factors

* les: increased connected bias to lower churn rate

* les: fixed clientPool.setLimits

* core: do not use mutex in GetAncestor

* les: bump factor db version again

* les: add metrics

* les, light: minor fixes

les: handler separation

* core, light, params: implement eip2028

* core, light: address comments

* core: address comments

* tests: disable Istanbul tx tests (until updated)

* core: address comment

* all: implement simple checkpoint syncing

cmd, les, node: remove callback mechanism

cmd, node: remove callback definition

les: simplify the registrar

les: expose checkpoint rpc services in the light client

les, light: don't store untrusted receipt

cmd, contracts, les: discard stale checkpoint

cmd, contracts/registrar: loose restriction of registeration

cmd, contracts: add replay-protection

all: off-chain multi-signature contract

params: deploy checkpoint contract for rinkeby

cmd/registrar: add raw signing mode for registrar

cmd/registrar, contracts/registrar, les: fixed messages

* cmd/registrar, contracts/registrar: fix lints

* accounts/abi/bind, les: address comments

* cmd, contracts, les, light, params: minor checkpoint sync cleanups

* cmd, eth, les, light: move checkpoint config to config file

* cmd, eth, les, params: address comments

* eth, les, params: address comments

* cmd: polish up the checkpoint admin CLI

* cmd, contracts, params: deploy new version contract

* cmd/checkpoint-admin: add another flag for clef mode signing

* cmd, contracts, les: rename and regen checkpoint oracle with abigen

* all: freezer style syncing

core, eth, les, light: clean up freezer relative APIs

core, eth, les, trie, ethdb, light: clean a bit

core, eth, les, light: add unit tests

core, light: rewrite setHead function

core, eth: fix downloader unit tests

core: add receipt chain insertion test

core: use constant instead of hardcoding table name

core: fix rollback

core: fix setHead

core/rawdb: remove canonical block first and then iterate side chain

core/rawdb, ethdb: add hasAncient interface

eth/downloader: calculate ancient limit via cht first

core, eth, ethdb: lots of fixes

* eth/downloader: print ancient disable log only for fast sync

* les, light: implement ODR transaction lookup by hash

* les: delete useless file

* internal/ethapi: always use backend to find transaction

* les, eth, internal/ethapi: renamed GetCanonicalTransaction to GetTransaction

* light: add canonical header verification to GetTransaction

* all: simplify timestamps to uint64

* tests: update definitions

* clef, faucet, mobile: leftover uint64 fixups

* ethash: fix tests

* graphql: update schema for timestamp

* ethash: remove unused variable

This PR is a more advanced form of the dirty-to-clean cacher (#18995),
where we reuse previous database write batches as datasets to uncache,
saving a dirty-trie-iteration and a dirty-trie-rlp-reencoding per block.

This change

- implements concurrent LES request serving even for a single peer.
- replaces the request cost estimation method with a cost table based on
  benchmarks which gives much more consistent results. Until now the
  allowed number of light peers was just a guess which probably contributed
  a lot to the fluctuating quality of available service. Everything related
  to request cost is implemented in a single object, the 'cost tracker'. It
  uses a fixed cost table with a global 'correction factor'. Benchmark code
  is included and can be run at any time to adapt costs to low-level
  implementation changes.
- reimplements flowcontrol.ClientManager in a cleaner and more efficient
  way, with added capabilities: There is now control over bandwidth, which
  allows using the flow control parameters for client prioritization.
  Target utilization over 100 percent is now supported to model concurrent
  request processing. Total serving bandwidth is reduced during block
  processing to prevent database contention.
- implements an RPC API for the LES servers allowing server operators to
  assign priority bandwidth to certain clients and change prioritized
  status even while the client is connected. The new API is meant for
  cases where server operators charge for LES using an off-protocol mechanism.
- adds a unit test for the new client manager.
- adds an end-to-end test using the network simulator that tests bandwidth
  control functions through the new API.

This change unbreaks the build and removes racy access to
disableCheckFreq. Even though the field is set while holding
the lock, it was read outside of the protected section.

For more information about this light client mode, read
https://hackmd.io/s/HJy7jjZpm

Most probably a copy/paste kind of error.
Found with gocritic `dupArg` checker.

TryUpdate does not call t.trie.TryUpdate(key, value) and calls t.trie.TryDelete
instead. The update operation simply deletes the corresponding entry, though
it could retrieve later by odr. However, it adds further network overhead.