157 lines
3.6 KiB
Go
157 lines
3.6 KiB
Go
package rpcfilters
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import (
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"errors"
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"sync"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/rpc"
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"github.com/pborman/uuid"
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)
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type filter struct {
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hashes []common.Hash
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mu sync.Mutex
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done chan struct{}
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}
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// AddHash adds a hash to the filter
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func (f *filter) AddHash(hash common.Hash) {
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f.mu.Lock()
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defer f.mu.Unlock()
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f.hashes = append(f.hashes, hash)
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}
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// PopHashes returns all the hashes stored in the filter and clears the filter contents
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func (f *filter) PopHashes() []common.Hash {
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f.mu.Lock()
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defer f.mu.Unlock()
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hashes := f.hashes
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f.hashes = nil
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return returnHashes(hashes)
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}
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func newFilter() *filter {
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return &filter{
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done: make(chan struct{}),
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}
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}
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// PublicAPI represents filter API that is exported to `eth` namespace
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type PublicAPI struct {
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filters map[rpc.ID]*filter
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filtersMu sync.Mutex
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latestBlockChangedEvent *latestBlockChangedEvent
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transactionSentToUpstreamEvent *transactionSentToUpstreamEvent
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}
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// NewPublicAPI returns a reference to the PublicAPI object
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func NewPublicAPI(latestBlockChangedEvent *latestBlockChangedEvent,
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transactionSentToUpstreamEvent *transactionSentToUpstreamEvent) *PublicAPI {
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return &PublicAPI{
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filters: make(map[rpc.ID]*filter),
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latestBlockChangedEvent: latestBlockChangedEvent,
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transactionSentToUpstreamEvent: transactionSentToUpstreamEvent,
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}
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}
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// NewBlockFilter is an implemenation of `eth_newBlockFilter` API
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// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newblockfilter
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func (api *PublicAPI) NewBlockFilter() rpc.ID {
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api.filtersMu.Lock()
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defer api.filtersMu.Unlock()
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f := newFilter()
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id := rpc.ID(uuid.New())
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api.filters[id] = f
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go func() {
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id, s := api.latestBlockChangedEvent.Subscribe()
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defer api.latestBlockChangedEvent.Unsubscribe(id)
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for {
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select {
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case hash := <-s:
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f.AddHash(hash)
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case <-f.done:
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return
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}
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}
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}()
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return id
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}
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// NewPendingTransactionFilter is an implementation of `eth_newPendingTransactionFilter` API
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// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_newpendingtransactionfilter
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func (api *PublicAPI) NewPendingTransactionFilter() rpc.ID {
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api.filtersMu.Lock()
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defer api.filtersMu.Unlock()
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f := newFilter()
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id := rpc.ID(uuid.New())
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api.filters[id] = f
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go func() {
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id, s := api.transactionSentToUpstreamEvent.Subscribe()
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defer api.transactionSentToUpstreamEvent.Unsubscribe(id)
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for {
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select {
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case hash := <-s:
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f.AddHash(hash)
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case <-f.done:
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return
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}
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}
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}()
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return id
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}
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// UninstallFilter is an implemenation of `eth_uninstallFilter` API
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// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_uninstallfilter
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func (api *PublicAPI) UninstallFilter(id rpc.ID) bool {
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api.filtersMu.Lock()
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f, found := api.filters[id]
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if found {
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delete(api.filters, id)
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}
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api.filtersMu.Unlock()
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if found {
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close(f.done)
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}
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return found
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}
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// GetFilterChanges returns the hashes for the filter with the given id since
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// last time it was called. This can be used for polling.
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//
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// https://github.com/ethereum/wiki/wiki/JSON-RPC#eth_getfilterchanges
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func (api *PublicAPI) GetFilterChanges(id rpc.ID) ([]common.Hash, error) {
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api.filtersMu.Lock()
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defer api.filtersMu.Unlock()
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if f, found := api.filters[id]; found {
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return f.PopHashes(), nil
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}
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return []common.Hash{}, errors.New("filter not found")
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}
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// returnHashes is a helper that will return an empty hash array case the given hash array is nil,
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// otherwise the given hashes array is returned.
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func returnHashes(hashes []common.Hash) []common.Hash {
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if hashes == nil {
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return []common.Hash{}
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}
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return hashes
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}
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