84 lines
2.3 KiB
Go
84 lines
2.3 KiB
Go
package shhext
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import (
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"fmt"
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"hash/fnv"
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"sync"
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"time"
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"github.com/ethereum/go-ethereum/common"
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whisper "github.com/status-im/whisper/whisperv6"
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)
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const (
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// defaultRequestsDelay will be used in RequestsRegistry if no other was provided.
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defaultRequestsDelay = 3 * time.Second
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)
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type requestMeta struct {
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timestamp time.Time
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lastUID common.Hash
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}
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// NewRequestsRegistry creates instance of the RequestsRegistry and returns pointer to it.
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func NewRequestsRegistry(delay time.Duration) *RequestsRegistry {
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return &RequestsRegistry{
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delay: delay,
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uidToTopics: map[common.Hash]common.Hash{},
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byTopicsHash: map[common.Hash]requestMeta{},
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}
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}
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// RequestsRegistry keeps map for all requests with timestamp when they were made.
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type RequestsRegistry struct {
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mu sync.Mutex
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delay time.Duration
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uidToTopics map[common.Hash]common.Hash
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byTopicsHash map[common.Hash]requestMeta
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}
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// Register request with given topics. If request with same topics was made in less then configured delay then error
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// will be returned.
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func (r *RequestsRegistry) Register(uid common.Hash, topics []whisper.TopicType) error {
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r.mu.Lock()
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defer r.mu.Unlock()
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topicsHash := topicsToHash(topics)
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if meta, exist := r.byTopicsHash[topicsHash]; exist {
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if time.Since(meta.timestamp) < r.delay {
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return fmt.Errorf("another request with the same topics was sent less than %s ago. Please wait for a bit longer, or set `force` to true in request parameters", r.delay)
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}
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}
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newMeta := requestMeta{
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timestamp: time.Now(),
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lastUID: uid,
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}
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r.uidToTopics[uid] = topicsHash
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r.byTopicsHash[topicsHash] = newMeta
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return nil
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}
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// Unregister removes request with given UID from registry.
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func (r *RequestsRegistry) Unregister(uid common.Hash) {
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r.mu.Lock()
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defer r.mu.Unlock()
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topicsHash, exist := r.uidToTopics[uid]
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if !exist {
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return
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}
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delete(r.uidToTopics, uid)
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meta := r.byTopicsHash[topicsHash]
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// remove topicsHash only if we are trying to unregister last request with this topic.
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if meta.lastUID == uid {
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delete(r.byTopicsHash, topicsHash)
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}
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}
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// topicsToHash returns non-cryptographic hash of the topics.
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func topicsToHash(topics []whisper.TopicType) common.Hash {
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hash := fnv.New32()
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for i := range topics {
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_, _ = hash.Write(topics[i][:]) // never returns error per documentation
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}
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return common.BytesToHash(hash.Sum(nil))
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}
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