62 lines
1.9 KiB
Markdown
62 lines
1.9 KiB
Markdown
# `tendermint/block`
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## Block
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TODO: document
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### Header
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### Validation
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### Data
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## PartSet
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PartSet is used to split a byteslice of data into parts (pieces) for transmission.
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By splitting data into smaller parts and computing a Merkle root hash on the list,
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you can verify that a part is legitimately part of the complete data, and the
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part can be forwarded to other peers before all the parts are known. In short,
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it's a fast way to propagate a large file over a gossip network.
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PartSet was inspired by the LibSwift project.
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Usage:
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```Go
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data := RandBytes(2 << 20) // Something large
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partSet := NewPartSetFromData(data)
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partSet.Total() // Total number of 4KB parts
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partSet.Count() // Equal to the Total, since we already have all the parts
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partSet.Hash() // The Merkle root hash
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partSet.BitArray() // A BitArray of partSet.Total() 1's
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header := partSet.Header() // Send this to the peer
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header.Total // Total number of parts
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header.Hash // The merkle root hash
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// Now we'll reconstruct the data from the parts
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partSet2 := NewPartSetFromHeader(header)
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partSet2.Total() // Same total as partSet.Total()
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partSet2.Count() // Zero, since this PartSet doesn't have any parts yet.
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partSet2.Hash() // Same hash as in partSet.Hash()
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partSet2.BitArray() // A BitArray of partSet.Total() 0's
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// In a gossip network the parts would arrive in arbitrary order, perhaps
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// in response to explicit requests for parts, or optimistically in response
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// to the receiving peer's partSet.BitArray().
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for !partSet2.IsComplete() {
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part := receivePartFromGossipNetwork()
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added, err := partSet2.AddPart(part)
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if err != nil {
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// A wrong part,
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// the merkle trail does not hash to partSet2.Hash()
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} else if !added {
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// A duplicate part already received
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}
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}
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data2, _ := ioutil.ReadAll(partSet2.GetReader())
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bytes.Equal(data, data2) // true
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```
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