git ssb

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var fs = require('fs')
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var proc = require('child_process')
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var pull = require('pull-stream')
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var toPull = require('stream-to-pull-stream')
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var paramap = require('pull-paramap')
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var multicb = require('multicb')
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var u = require('./util')
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var ssbRef = require('ssb-ref')
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exports.help = `
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Usage: git ssb reconstruct <msg>...
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  Reconstruct pack/idx blobs referenced by git-update messages.
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  On success, output the message ids and their pack and index blob ids.
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Arguments:
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  msg           ssb message id
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`
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function reconstructBlobsForMsg(sbot, msg, cb) {
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  var c = msg.value.content
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  if (!c) return cb(new TypeError('Bad message: ' + JSON.stringify(msg)))
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  var packs = Array.isArray(c.packs) && c.packs.length === 1 && c.packs
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  var idxs = Array.isArray(c.indexes) && c.indexes.length === 1 && c.indexes
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  var packId = packs && packs[0] && packs[0].link
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  var idxId = idxs && idxs[0] && idxs[0].link
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  if (!packId || !idxId) return cb(new TypeError('Message should have ' +
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    'exactly one pack link and idx link'))
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  var commits = Array.isArray(c.commits) ? c.commits : []
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  var commitIds = commits.map(function (commit) { return commit.sha1 })
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  var objectIds = Array.isArray(c.object_ids) ? c.object_ids : []
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  var allObjectIds = commitIds.concat(objectIds)
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  if (c.num_objects && c.num_objects !== allObjectIds.length) {
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    return cb(new Error('Message ' + msg.key + ' ' +
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      'does not have information to reconstruct its blobs'))
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  }
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  // replace incorrectly hashed empty blob id
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  allObjectIds = allObjectIds.map(function (id) {
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    return id === '77e98a59e190ce51ab7ec86deb24492d1434247e'
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      ? 'e69de29bb2d1d6434b8b29ae775ad8c2e48c5391' : id
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  })
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  var tmpName = 'git-ssb-reconstruct'
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  var child = proc.spawn('git', ['pack-objects', '-q', tmpName], {
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    stdio: ['pipe', 'pipe', process.stderr],
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  })
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  child.stdin.end(allObjectIds.join('\n'))
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  var bufs = []
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  child.stdout.on('data', bufs.push.bind(bufs))
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  child.on('error', onError)
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  function onError(err) {
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    if (!cb) return console.trace(err)
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    var _cb = cb
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    cb = null
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    _cb(err)
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  }
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  var done = multicb()
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  child.on('exit', done())
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  child.stdout.on('end', done())
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  done(function (code) {
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    if (code) return onError(new Error('failed to pack git objects. code: ' + code))
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    if (!cb) return
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    var hash = Buffer.concat(bufs).toString('utf8').trim()
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    if (!hash) return cb(new Error('missing hash'))
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    var packFile = tmpName + '-' + hash + '.pack'
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    var idxFile = tmpName + '-' + hash + '.idx'
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    var done = multicb()
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    pull(
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      toPull(fs.createReadStream(packFile)),
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      sbot.blobs.add(packId, done())
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    )
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    pull(
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      toPull(fs.createReadStream(idxFile)),
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      sbot.blobs.add(idxId, done())
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    )
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    done(function (err) {
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      var done = multicb()
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      fs.unlink(packFile, done())
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      fs.unlink(idxFile, done())
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      done()(err)
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      done(function (err) {
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        if (err) return cb(err)
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        cb(null, {msg: msg, packId: packId, idxId: idxId})
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      })
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    })
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  })
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}
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exports.fn = function (argv) {
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  if (argv._.length < 1) return u.help('reconstruct')
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  var msgIds = argv._
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  if (!msgIds.every(ssbRef.isMsgId)) throw 'invalid message ids: ' +
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    JSON.stringify(argv._)
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  u.getSbot(argv, function (err, sbot) {
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    if (err) throw err
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    pull(
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      pull.values(msgIds),
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      paramap(function (id, cb) {
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        u.getMsg(sbot, id, function (err, msg) {
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          if (err) throw 'failed to get message ' + id + ': ' + (err.stack||err)
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          cb(null, msg)
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        })
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      }, 8),
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      paramap(function (msg, cb) {
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        u.unbox(sbot, msg, function (err, msg) {
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          if (err) throw 'failed to get decrypt message ' + id
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          cb(null, msg)
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        })
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      }, 4),
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      pull.asyncMap(function (msg, cb) {
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        reconstructBlobsForMsg(sbot, msg, cb)
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      }),
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      pull.drain(function (obj) {
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        console.log(obj.msg.key + ' ' + obj.packId + ' ' + obj.idxId)
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      }, function (err) {
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        if (err) throw err
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        sbot.close()
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      })
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    )
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  })
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}
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