git ssb

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var Graphmitter = require('graphmitter')
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var pull        = require('pull-stream')
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var mlib        = require('ssb-msgs')
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var memview     = require('level-memview')
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var pushable    = require('pull-pushable')
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var mdm         = require('mdmanifest')
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var valid       = require('scuttlebot/lib/validators')
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var apidoc      = require('scuttlebot/lib/apidocs').friends
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// friends plugin
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// methods to analyze the social graph
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// maintains a 'follow' and 'flag' graph
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function isFunction (f) {
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  return 'function' === typeof f
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}
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function isString (s) {
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  return 'string' === typeof s
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}
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function isFriend (friends, a, b) {
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  return friends[a] && friends[b] && friends[a][b] && friends[b][a]
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}
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exports.name = 'friends'
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exports.version = '1.0.0'
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exports.manifest = mdm.manifest(apidoc)
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exports.init = function (sbot, config) {
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  var graphs = {
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    follow: new Graphmitter(),
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    flag: new Graphmitter()
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  }
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  // view processor
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  var syncCbs = []
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  function awaitSync (cb) {
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    if (syncCbs) syncCbs.push(cb)
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    else cb()
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  }
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  // read/watch the log for changes to the social graph
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  pull(sbot.createLogStream({ live: true }), pull.drain(function (msg) {
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    if (msg.sync) {
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      syncCbs.forEach(function (cb) { cb() })
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      syncCbs = null
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      if (sbot.gossip) {
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        // prioritize friends
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        var friends = graphs['follow'].toJSON()
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        sbot.gossip.peers().forEach(function(peer) {
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          if (isFriend(friends, sbot.id, peer.key)) {
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            sbot.gossip.add(peer, 'friends')
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          }
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        })
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      }
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      return
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    }
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    var c = msg.value.content
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    if (c.type == 'contact') {
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      mlib.asLinks(c.contact, 'feed').forEach(function (link) {
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        if ('following' in c) {
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          if (c.following)
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            graphs.follow.edge(msg.value.author, link.link, true)
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          else
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            graphs.follow.del(msg.value.author, link.link)
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        }
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        if ('flagged' in c) {
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          if (c.flagged)
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            graphs.flag.edge(msg.value.author, link.link, c.flagged)
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          else
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            graphs.flag.del(msg.value.author, link.link)
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        }
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      })
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    }
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  }))
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  return {
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    get: valid.sync(function (opts) {
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      var g = graphs[opts.graph || 'follow']
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      if(!g) throw new Error('opts.graph must be provided')
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      return g.get(opts.source, opts.dest)
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    }, 'object?'),
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    all: valid.async(function (graph, cb) {
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      if (typeof graph == 'function') {
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        cb = graph
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        graph = null
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      }
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      if (!graph)
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        graph = 'follow'
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      awaitSync(function () {
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        cb(null, graphs[graph] ? graphs[graph].toJSON() : null)
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      })
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    }, 'string?'),
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    path: valid.sync(function (opts) {
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      if(isString(opts))
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        opts = {source: sbot.id, dest: opts}
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      return graphs.follow.path(opts)
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    }, 'string|object'),
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    createFriendStream: valid.source(function (opts) {
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      opts = opts || {}
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      var live = opts.live === true
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      var meta = opts.meta === true
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      var start = opts.start || sbot.id
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      var graph = graphs[opts.graph || 'follow']
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      if(!graph)
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        return pull.error(new Error('unknown graph:' + opts.graph))
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      var cancel, ps = pushable(function () {
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        cancel && cancel()
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      })
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      function push (to, hops) {
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        return ps.push(meta ? {id: to, hops: hops} : to)
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      }
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      //by default, also emit your own key.
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      if(opts.self !== false)
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        push(start, 0)
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      var conf = config.friends || {}
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      cancel = graph.traverse({
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        start: start,
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        hops: opts.hops || conf.hops || 3,
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        max: opts.dunbar || conf.dunbar || 150,
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        each: function (_, to, hops) {
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          if(to !== start) push(to, hops)
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        }
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      })
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      if(!live) { cancel(); ps.end() }
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      return ps
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    }, 'createFriendStreamOpts?'),
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    hops: valid.async(function (start, graph, opts, cb) {
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      if (typeof opts == 'function') { // (start|opts, graph, cb)
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        cb = opts
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        opts = null
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      } else if (typeof graph == 'function') { // (start|opts, cb)
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        cb = graph
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        opts = graph = null
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      }
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      opts = opts || {}
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      if(isString(start)) { // (start, ...)
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        // first arg is id string
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        opts.start = start
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      } else if (start && typeof start == 'object') { // (opts, ...)
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        // first arg is opts
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        for (var k in start)
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          opts[k] = start[k]
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      }
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      var conf = config.friends || {}
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      opts.start  = opts.start  || sbot.id
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      opts.dunbar = opts.dunbar || conf.dunbar || 150
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      opts.hops   = opts.hops   || conf.hops   || 3
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      var g = graphs[graph || 'follow']
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      if (!g)
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        return cb(new Error('Invalid graph type: '+graph))
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      awaitSync(function () {
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        cb(null, g.traverse(opts))
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      })
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    }, ['feedId', 'string?', 'object?'], ['createFriendStreamOpts'])
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  }
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}
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