Factor methods out into ConversionManager

services/track-changes/app/coffee/ConversionManager.coffee

@@ -0,0 +1,62 @@
+{db, ObjectId} = require "./mongojs"
+ConcatManager = require "./ConcatManager"
+
+module.exports = ConversionManager =
+	OPS_TO_LEAVE: 10
+
+	removeLatestCompressedUpdate: (doc_id, callback = (error) ->) ->
+		db.docHistory.update { doc_id: ObjectId(doc_id) }, { $pop: { docOps: 1 } }, callback
+
+	getLatestCompressedUpdate: (doc_id, callback = (error) ->) ->
+		db.docHistory.find { doc_id: ObjectId(doc_id) }, { docOps: { $slice: -1 } }, (error, history) ->
+			return callback(error) if error?
+			history = history[0] or { docOps: [] }
+			callback null, history.docOps.slice(-1)[0]
+
+	insertCompressedUpdates: (doc_id, updates, callback = (error) ->) ->
+		db.docHistory.update { doc_id: ObjectId(doc_id) }, { $push: { docOps: { $each: updates } } }, { upsert: true }, callback
+
+	trimLastRawUpdate: (doc_id, tailVersion, callback = (error) ->) ->
+		db.docOps.update { doc_id: ObjectId(doc_id) }, { $pop: { docOps: -1 }, $set: { tailVersion: tailVersion + 1 } }, callback
+
+	getLastRawUpdateAndVersion: (doc_id, callback = (error, update, currentVersion, tailVersion) ->) ->
+		db.docOps.find { doc_id: ObjectId(doc_id) }, { version: true, tailVersion: true, docOps: { $slice: 1 } }, (error, docs) ->
+			return callback(error) if error?
+			return callback(new Error("doc not found")) if docs.length == 0
+			doc = docs[0]
+			callback null, doc.docOps[0], doc.version, doc.tailVersion or 0
+
+	convertOldestRawUpdate: (doc_id, callback = (error, converted) ->) ->
+		ConversionManager.getLastRawUpdateAndVersion doc_id, (error, rawUpdate, currentVersion, tailVersion) ->
+			return callback(error) if error?
+
+			rawUpdates = ConcatManager.normalizeUpdate(rawUpdate)
+
+			if currentVersion - tailVersion > ConcatManager.OPS_TO_LEAVE
+				ConversonManager.getLatestCompressedUpdate doc_id, (error, lastCompressedUpdate) ->
+					return callback(error) if error?
+
+					removeAndModifyPreviousCompressedUpdate = (callback, compressedUpdates) ->
+						if lastCompressedUpdate?
+							compressedUpdates = [lastCompressedUpdate]
+							for rawUpdate in rawUpdates
+								lastCompressedUpdate = compressedUpdates.pop()
+								compressedUpdates = compressedUpdates.concat ConcatManager.concatTwoUpdates lastCompressedUpdate, rawUpdate
+							ConversionManager.removeLatestCompressedUpdate doc_id, (error) ->
+								return callback(error) if error?
+								callback null, compressUpdates
+						else
+							callback null, rawUpdates
+						
+					removeAndModifyPreviousCompressedUpdate (error, newCompressedUpdates) ->
+						return callback(error) if error?
+						ConversionManager.insertCompressedUpdates doc_id, newCompressedUpdates, (error) ->
+							return callback(error) if error?
+							ConversionManager.trimLastRawUpdate doc_id, tailVersion, (error) ->
+								return callback(error) if error?
+								console.log "Pushed op", tailVersion
+								callback null, true
+
+			else
+				console.log "Up to date"
+				callback null, false

services/track-changes/compressHistory.coffee

@@ -1,26 +1,9 @@
-{db, ObjectId} = require "./app/js/mongojs"
-ConcatManager = require "./app/js/ConcatManager"
+{db, ObjectId} = require "./app/coffee/mongojs"
+ConversionManager = require "./app/coffee/ConversionManager"
 
 doc_id = process.argv.pop()
 console.log "DOC ID", doc_id
 
-OPS_TO_LEAVE = 10
-
-removeLatestCompressedUpdate = (doc_id, callback = (error) ->) ->
-	db.docHistory.update { doc_id: ObjectId(doc_id) }, { $pop: { docOps: 1 } }, callback
-
-getLatestCompressedUpdate = (doc_id, callback = (error) ->) ->
-	db.docHistory.find { doc_id: ObjectId(doc_id) }, { docOps: { $slice: -1 } }, (error, history) ->
-		return callback(error) if error?
-		history = history[0] or { docOps: [] }
-		callback null, history.docOps.slice(-1)[0]
-
-insertCompressedUpdates = (doc_id, updates, callback = (error) ->) ->
-	db.docHistory.update { doc_id: ObjectId(doc_id) }, { $push: { docOps: { $each: updates } } }, { upsert: true }, callback
-
-trimLastRawUpdate = (doc_id, tailVersion, callback = (error) ->) ->
-	db.docOps.update { doc_id: ObjectId(doc_id) }, { $pop: { docOps: -1 }, $set: { tailVersion: tailVersion + 1 } }, callback
-
 done = () ->
 	console.log "DONE! Here's the history:"
 	db.docHistory.find { doc_id: ObjectId(doc_id) }, (error, docs) ->
@@ -35,40 +18,11 @@ done = () ->
 		process.exit()
 
 do next = () ->
-	db.docOps.find { doc_id: ObjectId(doc_id) }, { version: true, tailVersion: true, docOps: { $slice: 1 } }, (error, docs) ->
+	ConversionManager.convertOldestRawUpdate doc_id, (error, converted) ->
 		throw error if error?
-		throw "doc not found" if docs.length < 1
-		doc = docs[0]
-		tailVersion = doc.tailVersion or 0
-		version = doc.version
-
-		rawUpdate = doc.docOps[0]
-		rawUpdates = ConcatManager.normalizeUpdate(rawUpdate)
-
-		if version - tailVersion > OPS_TO_LEAVE
-			getLatestCompressedUpdate doc_id, (error, lastCompressedUpdate) ->
-				throw error if error?
-				if lastCompressedUpdate?
-					compressedUpdates = [lastCompressedUpdate]
-					for rawUpdate in rawUpdates
-						lastCompressedUpdate = compressedUpdates.pop()
-						compressedUpdates = compressedUpdates.concat ConcatManager.concatTwoUpdates lastCompressedUpdate, rawUpdate
-					removeLatestCompressedUpdate doc_id, (error) ->
-						throw error if error?
-						insertCompressedUpdates doc_id, compressedUpdates, (error) ->
-							throw error if error?
-							trimLastRawUpdate doc_id, tailVersion, (error) ->
-								throw error if error?
-								console.log "Pushed compressed op"
-								next()
-				else
-					insertCompressedUpdates doc_id, rawUpdates, (error) ->
-						trimLastRawUpdate doc_id, tailVersion, (error) ->
-							throw error if error?
-							console.log "Pushed first op"
-							next()
+		if converted
+			next()
 		else
-			console.log "Up to date"
 			done()
-
+