Alex A. Naanou f25a3ce8ca more refactoring...
Signed-off-by: Alex A. Naanou <alex.nanou@gmail.com>
2014-12-28 23:49:42 +03:00

295 lines
7.6 KiB
JavaScript
Executable File

/**********************************************************************
*
*
*
**********************************************************************/
var pathlib = require('path')
var events = require('events')
var fse = require('fs.extra')
var glob = require('glob')
var promise = require('promise')
define(function(require){ var module = {}
console.log('>>> file')
//var DEBUG = DEBUG != null ? DEBUG : true
var tasks = require('lib/tasks')
/*********************************************************************/
var INDEX_DIR = '.ImageGrid'
/*********************************************************************/
// Queue
//
// Task
//
/*********************************************************************/
// helpers...
// Guarantee that the 'end' and 'match' handlers will always get called
// with all results at least once...
//
// This does two things:
// - every 'end' event handler will get the full result set, regardless
// of when it was set...
// - every 'match' handler will be called for every match found, again
// regardless of whether it was set before or after the time of
// match.
//
// This prevents handlers from missing the event they are waiting for,
// essentially making it similar to how Promise/Deferred handle their
// callbacks.
//
var guaranteeGlobEvents =
module.guaranteeGlobEvents =
function guaranteeGlobEvents(glob, all_matches){
all_matches = all_matches == null ? true : false
var visited = []
return glob
// keep track of visited matches...
.on('match', function(path){
all_matches && visited.push(path)
})
// trigger new handlers...
.on('newListener', function(evt, func){
// trigger the 'end' handler if we have already finished...
if(evt == 'end' && this.found != null){
func.call(this, this.found)
// trigger the 'match' handler for each match already found...
} else if(all_matches && evt == 'match' && visited.length > 0){
visited.forEach(function(path){
func.call(this, path)
})
}
})
}
/*********************************************************************/
// Reader...
// XXX return a promise rather than an event emitter (???)
// XXX glob has a problem: if a match happens fast enough and we are slow
// enough to register a 'match' handler, then that match(s) will get
// missed...
function listIndexes(base){
return guaranteeGlobEvents(glob(base +'/**/'+ INDEX_DIR))
}
// XXX return a promise rather than an event emitter (???)
function listJSON(path, pattern){
pattern = pattern || '*'
return guaranteeGlobEvents(glob(path +'/'+ pattern +'.json'))
}
var loadFile = promise.denodeify(fse.readFile)
// XXX handle errors...
function loadJSON(path){
return loadFile(path).then(JSON.parse)
}
// json file name format:
// [<timestamp>-]<keyword>[-diff].json
//
// events emited:
// - queued <path> - json file path queued for loading
// - loaded <path> - done loading json file path
// - index <path> <data> - done loading index at path
// - error <err> - an error occurred...
//
// NOTE: logger must be an event emitter...
//
// XXX test with:
// requirejs(['file'],
// function(m){
// f = m.loadIndex("L:/mnt/hdd15 (photo)/NTFS1/media/img/others") })
// .done(function(d){ console.log(d) })
// XXX need to do better error handling...
// XXX a bit overcomplicated (???), see if this can be split into more generic
// sections...
var loadIndex =
module.loadIndex =
function(path, logger){
var p = path.split(INDEX_DIR)
var last = p.slice(-1)[0].trim()
return new promise(function(resolve, reject){
// we've got an index...
if(p.length > 1 && /^\/*$/.test(last)){
listJSON(path)
// XXX handle errors...
.on('error', function(err){
logger && logger.emit('error', err)
})
.on('end', function(files){
var res = {}
var index = {}
var root = {}
// group by keyword...
files
.sort()
.reverse()
.forEach(function(n){
var b = pathlib.basename(n)
var s = b.split(/[-.]/g).slice(0, -1)
// <keyword>.json / non-diff
// NOTE: this is a special case, we add this to
// a seporate index and then concat it to
// the final list if needed...
if(s.length == 1){
var k = s[0]
root[k] = n
return
// <timestamp>-<keyword>[-diff].json / diff / non-diff
} else {
var k = s[1]
var d = s[2] == 'diff'
}
// new keyword...
if(index[k] == null){
index[k] = [[d, n]]
logger && logger.emit('queued', n)
// do not add anything past the latest non-diff
// for each keyword...
} else if(index[k].slice(-1)[0][0] == true){
index[k].push([d, n])
logger && logger.emit('queued', n)
}
})
// add base files back where needed...
Object.keys(root)
.forEach(function(k){
var n = root[k]
// no diffs...
if(index[k] == null){
index[k] = [[false, n]]
logger && logger.emit('queued', n)
// add root file if no base is found...
} else if(index[k].slice(-1)[0][0] == true){
index[k].push([false, n])
logger && logger.emit('queued', n)
}
})
// load...
promise
.all(Object.keys(index).map(function(k){
// get relevant paths...
var diffs = index[k]
var latest = diffs.splice(-1)[0][1]
// NOTE: so far I really do not like how nested and
// unreadable the Promise/Deferred code becomes
// even with a small rise in complexity...
// ...for example, the following code is quite
// simple, but does not look the part.
//
// Maybe it's a style thing...
// load latest...
return loadJSON(latest)
.then(function(data){
// handle diffs...
return promise
.all(diffs
.reverse()
.map(function(p){
p = p[1]
// load diff...
return loadJSON(p)
// XXX handle errors...
// XXX we should abort loading this index...
.catch(function(err){
logger && logger.emit('error', err)
})
.done(function(json){
// merge...
for(var k in json){
data[k] = json[k]
}
logger && logger.emit('loaded', p)
})
}))
.then(function(){
res[k] = data
logger && logger.emit('loaded', latest)
})
})
}))
.then(function(){
logger && logger.emit('index', path, res)
var d = {}
d[path] = res
resolve(d)
})
})
// no explicit index given -- find all in sub tree...
} else {
var res = {}
// XXX handle 'error' event...
listIndexes(path)
// XXX handle errors...
.on('error', function(err){
logger && logger.emit('error', err)
})
// collect the found indexes...
.on('match', function(path){
loadIndex(path, logger)
.done(function(obj){ res[path] = obj[path] })
})
// done...
.on('end', function(paths){
resolve(res)
})
}
})
}
/*********************************************************************/
// Writer...
/**********************************************************************
* vim:set ts=4 sw=4 : */
return module })