git ssb

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var pull = require('pull-stream')
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var createEbtStream = require('./')
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var Obv = require('obv')
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//create a datamodel for a reliable chat room.
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function createChatModel (id, log) {
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  //in this example, logs can be a map of arrays,
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  var logs = {}
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  if(id) logs[id] = log || []
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  var onAppend = Obv()
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  return {
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    logs: logs,
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    append: function append (msg) {
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      (logs[msg.author] = logs[msg.author] || []).push(msg)
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      onAppend.set(msg)
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    },
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    onAppend: onAppend
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  }
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}
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function createStream(chat) {
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  //so the vector clock can be
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  var vectorClock = {}
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  for(var k in chat.logs)
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    vectorClock[k] = chat.logs[k].length
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  //observables are like an event emitter but with a stored value
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  //and only one value per instance (instead of potentially many named events)
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  var stream = createEbtStream(
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    //pass a get(id, seq, cb)
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    function (id, seq, cb) {
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      if(!chat.logs[id] || !chat.logs[id][seq-1])
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        return cb(new Error('not found'))
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      cb(null, chat.logs[id][seq-1])
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    },
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    //pass append(msg, cb)
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    function (msg, cb) {
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      chat.append(msg)
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      cb()
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    }
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  ) ({
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    seqs: vectorClock,
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  })
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  chat.onAppend(stream.onAppend)
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  return stream
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}
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if(!module.parent) {
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  var alice = createChatModel('alice', [])
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  var bob = createChatModel('bob')
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  var as = createStream(alice)
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  var bs = createStream(bob)
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  pull(as, bs, as)
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  //have bob get ready to receive something
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  bob.onAppend(function (msg) {
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    console.log('msg at bob:', msg)
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  })
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  //have alice send a message to bob
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  alice.append({author: 'alice', sequence: 1, content: 'hello bob!'})
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}
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exports.createChatModel = createChatModel
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exports.createStream = createStream
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