'use strict';
var upsert = require('./upsert');
var utils = require('./utils');
var Promise = utils.Promise;
module.exports = function (opts) {
var sourceDB = opts.db;
var viewName = opts.viewName;
var mapFun = opts.map;
var reduceFun = opts.reduce;
var temporary = opts.temporary;
// the "undefined" part is for backwards compatibility
var viewSignature = mapFun.toString() + (reduceFun && reduceFun.toString()) +
'undefined';
if (!temporary && sourceDB._cachedViews) {
var cachedView = sourceDB._cachedViews[viewSignature];
if (cachedView) {
return Promise.resolve(cachedView);
}
}
return sourceDB.info().then(function (info) {
var depDbName = info.db_name + '-mrview-' +
(temporary ? 'temp' : utils.MD5(viewSignature));
// save the view name in the source db so it can be cleaned up if necessary
// (e.g. when the _design doc is deleted, remove all associated view data)
function diffFunction(doc) {
doc.views = doc.views || {};
var fullViewName = viewName;
if (fullViewName.indexOf('/') === -1) {
fullViewName = viewName + '/' + viewName;
}
var depDbs = doc.views[fullViewName] = doc.views[fullViewName] || {};
/* istanbul ignore if */
if (depDbs[depDbName]) {
return; // no update necessary
}
depDbs[depDbName] = true;
return doc;
}
return upsert(sourceDB, '_local/mrviews', diffFunction).then(function () {
return sourceDB.registerDependentDatabase(depDbName).then(function (res) {
var db = res.db;
db.auto_compaction = true;
var view = {
name: depDbName,
db: db,
sourceDB: sourceDB,
adapter: sourceDB.adapter,
mapFun: mapFun,
reduceFun: reduceFun
};
return view.db.get('_local/lastSeq').catch(function (err) {
/* istanbul ignore if */
Iif (err.status !== 404) {
throw err;
}
}).then(function (lastSeqDoc) {
view.seq = lastSeqDoc ? lastSeqDoc.seq : 0;
if (!temporary) {
sourceDB._cachedViews = sourceDB._cachedViews || {};
sourceDB._cachedViews[viewSignature] = view;
view.db.on('destroyed', function () {
delete sourceDB._cachedViews[viewSignature];
});
}
return view;
});
});
});
});
};
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