git ssb

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var Pull = require("pull-stream");
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var KVSet = require("kvset");
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var Pad = require("pad-ipv6");
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var Query = module.exports = {};
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Query.branches = function (sbot, name, type, _class, cb) {
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    if (!_class) _class = "IN";
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    var branches = [];
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    Pull(Query.all(sbot),
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    Pull.filter(function (record) {
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        return record.name == name
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            && record.type == type
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            && record.class == _class;
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    }),
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    Query.drainSet(function (record) {
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        branches.push(record.id);
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    }, function (err) {
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        cb(err, branches);
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    }));
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};
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function msgToRecord(msg) {
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    var c = msg.value.content;
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    var r = c && c.record;
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    if (!r) return;
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    r.id = msg.key;
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    r.author = msg.value.author;
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    r.timestamp = msg.value.timestamp;
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    r.branch = c.branch;
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    if (!r.ttl) r.ttl = 500;
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    if (!r.class) r.class = "IN";
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    if (r.value) r.data = r.value, delete r.value
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    if (r.type === 'AAAA') r.data = Pad(r.data);
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    return r;
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}
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Query.all = function (sbot) {
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    return Pull(sbot.messagesByType({
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        type: 'ssb-dns',
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    }),
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    Pull.map(msgToRecord),
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    Pull.filter());
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};
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function expandName(name, wildcard) {
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    var names = {};
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    for (var labels = name.split(/\./); labels.length; labels.shift()) {
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        if (wildcard) labels[0] = wildcard;
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        names[labels.join('.')] = true;
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    }
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    return names;
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}
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function Wildcards() {
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    this.lengths = [];
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    this.recordsByLength = {};
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}
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Wildcards.prototype.addRecord = function (record) {
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    var len = record.name.length;
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    if (len in this.recordsByLength) {
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        this.recordsByLength[len].push(record);
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    } else {
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        this.recordsByLength[len] = [record];
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        this.lengths.push(len);
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    }
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};
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Wildcards.prototype.getRecords = function () {
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    // get records for the longest name length
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    if (this.lengths.length) {
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        var len = Math.max.apply(Math, this.lengths);
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        return this.recordsByLength[len] || [];
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    }
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    return [];
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};
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function ZoneSerials() {
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    this.serials = {};
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}
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ZoneSerials.prototype.addRecord = function (record) {
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    for (var zone in expandName(record.name)) {
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        this.serials[zone] = (+this.serials[zone] || 0) + 1;
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    }
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};
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ZoneSerials.prototype.getSerial = function (zone) {
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    return this.serials[zone] % 0x100000000;
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};
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Query.drainSet = function (each, onEnd) {
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    var set = new KVSet();
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    return Pull.drain(function (record) {
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        if (record.branch) set.remove(record.branch);
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        set.add(record.id, record);
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    }, function (err) {
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        if (err) return onEnd(err);
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        for (var key in set.heads) {
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            var record = set.heads[key];
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            try {
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                each(record);
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            } catch(e) {
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                return onEnd(e);
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            }
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        }
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        onEnd(null);
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    });
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};
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Query.query = function (sbot, question, cb) {
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    // look up records that match a question, including wildcard records
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    // and zone authority records
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    var authorityDomains = expandName(question.name);
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    var wildcardDomains = expandName(question.name, '*');
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    var authorities = new Wildcards();
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    var answers = new Wildcards();
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    var zoneSerials = new ZoneSerials();
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    var result = {};
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    Pull(Query.all(sbot),
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    Pull.filter(function (record) {
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        zoneSerials.addRecord(record);
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        var nameMatches = record.name == question.name
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            || record.name in wildcardDomains
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        if (nameMatches) {
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            result.domainExists = true;
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        }
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        if (record.type === 'SOA') {
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            return record.name in authorityDomains
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        }
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        return nameMatches
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            && record.type == question.type
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            && record.class == question.class;
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    }),
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    Query.drainSet(function (record) {
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        if (record.type === 'SOA') {
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            result.authoritative = true;
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            if (question.type === 'SOA'
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              && question.class === record.class
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              && (question.name === record.name
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                    || record.name in wildcardDomains)) {
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                answers.addRecord(record);
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            } else {
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                authorities.addRecord(record);
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            }
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        } else {
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            answers.addRecord(record);
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        }
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    }, function (err) {
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        if (err) return cb(err);
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        result.answers = answers.getRecords();
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        result.authorities = authorities.getRecords();
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        result.authorities.forEach(function (auth) {
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            if (!auth.data.serial) {
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                // special case: calculate a serial for the SOA
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                auth.data.serial = zoneSerials.getSerial(auth.name);
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            }
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        });
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        cb(null, result);
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    }));
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};
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