Class: TVC

Inherits:
Object
  • Object
show all
Defined in:
lib/tvc.rb

Instance Method Summary collapse

Constructor Details

#initialize(args) ⇒ TVC

main function



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# File 'lib/tvc.rb', line 589

def initialize(args)
	# get directories for use later
	@runDir= Dir.getwd
	@repoDir = getRepositoryDirectory

	# if we're not initializing and we have no repository
	# issue an error and exit
	if args[0] != "init" && @repoDir.nil?
		repositoryIssueError
		Process.exit
	end
	# switch based on command
	case args[0]
	when "init"
		if @repoDir.nil?
			init
		else
			puts "Repository already initialized"
		end
	when "commit"
		commit args[1]
	when "replace"
		replace args[1]
	when "rollback"
		replace args[1]
		commit "Rolled back to #{args[1]}"
	when "reset"
		replace(getCurrentEntry["hash"])
	when "history"
		history
	when "branch"
		if not args[1].nil?
			branch args[1]
		else
			listBranches
		end
	when "checkout"
		checkout args[1]
	when "merge"
		merge args[1]
	when "status"
		status
	else
		help
	end
end

Instance Method Details

#addBranchEntry(entry) ⇒ Object

add an entry to the branch list



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# File 'lib/tvc.rb', line 546

def addBranchEntry(entry)
	branches = getBranches
	branches << entry
	saveBranches(branches)
end

#addHistoryEntry(entry) ⇒ Object

adds an entry to the history file



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# File 'lib/tvc.rb', line 423

def addHistoryEntry(entry)
	versions = getHistoryEntries
	versions << entry
	saveDataToJson(File.join(@repoDir, "history"), versions)
end

#branch(name) ⇒ Object

create a branch



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# File 'lib/tvc.rb', line 79

def branch(name)
	b = findBranch(name)
	if b.nil?
		current = getCurrentEntry
		newBranch = {"name" => name, "hash" => current["hash"], "parent" => current["hash"]}
		addBranchEntry(newBranch)
	else
		puts "Branch already exists"
	end
end

#changeBranchHash(name, hash) ⇒ Object

changes the hash for a specified branch, and sets the parent to the previous hash



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# File 'lib/tvc.rb', line 404

def changeBranchHash(name, hash)
	b = findBranch(name)
	branches = getBranches
	branches.each do |branch|
		if branch == b
			branch["parent"] = branch["hash"]
			branch["hash"] = hash
			saveBranches(branches)
			return
		end
	end
end

#changeCurrentEntry(entry) ⇒ Object

change the entry in the current file



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# File 'lib/tvc.rb', line 435

def changeCurrentEntry(entry)
	newEntry = [entry]
	saveDataToJson(File.join(@repoDir, "current"), newEntry)
end

#checkout(branchName) ⇒ Object

checkout a branch



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# File 'lib/tvc.rb', line 91

def checkout(branchName)
	checkoutBranch = findBranch(branchName)
	if not checkoutBranch.nil?
		changeCurrentEntry(checkoutBranch)
		replace(checkoutBranch["hash"])
	else
		puts "Branch does not exist"
		return
	end
end

#commit(message) ⇒ Object

commit current changes



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# File 'lib/tvc.rb', line 36

def commit(message)
	hash = createObjects(@runDir)
	current = getCurrentEntry
	data = {"message" => message, "hash" => hash, "parent" => current["hash"]}
	addHistoryEntry(data)
	current["parent"] = data["parent"]
	current["hash"] = data["hash"]
	changeCurrentEntry(current)
	changeBranchHash(current["name"], current["hash"])
	puts hash
	puts message
end

#compress(data) ⇒ Object

compresses given data



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# File 'lib/tvc.rb', line 393

def compress(data)
	Zlib::Deflate.deflate(data)
end

#createHash(filePath) ⇒ Object

create a sha2 hash of a file



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# File 'lib/tvc.rb', line 534

def createHash(filePath)
	hashfunc = Digest::SHA2.new
	open(filePath, "rb") do |io|
		while !io.eof
			readBuffer = io.readpartial(1024)
			hashfunc.update(readBuffer)
		end
	end
	return hashfunc.hexdigest
end

#createItem(directory, entry) ⇒ Object

attempt to create the item specified in the entry



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# File 'lib/tvc.rb', line 342

def createItem(directory, entry)
	# each "tree" item specifies a directory that should be made corresponding to 
	# that directory's json file (hash)
	if entry["type"] == "tree"
		d = directory + '/' + entry["name"]
		Dir.mkdir(d)
		dirJson = getDataFromJson(File.join(getObjectsDirectory, entry["hash"]))
		moveFiles(d, dirJson)
	# copy the item out of the objects folder into its proper place
	elsif entry["type"] == "blob"
		f = File.open(File.join(directory, entry["name"]), "w")
		f.write(getFileData(File.join(getObjectsDirectory, entry["hash"])))
		f.close
	end
end

#createObjects(directoryName) ⇒ Object

save objects in the objects folder, based on hash create json files to index them



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# File 'lib/tvc.rb', line 500

def createObjects(directoryName)
	objects = []
	Dir.foreach(directoryName) do |dir|
		dirpath = directoryName + '/' + dir
		# go down into each valid directory and make objects for its contents
		if File.directory?(dirpath)
			if dir != '.' && dir != '..' && dir != ".tvc"
				hash = createObjects(dirpath)
				data = { "type" => "tree", "name" => dir, "hash" => hash }
				objects << data
			end
		# create a hash based on the file contents
		else
			fileData = File.open(dirpath, "rb") { |f| f.read }
			tempFileName = File.join(@repoDir, "temp")
			saveFileData(tempFileName, fileData)
			hash = createHash(tempFileName)
			data = { "type" => "blob", "name" => dir, "hash" => hash }
			FileUtils.cp(tempFileName, File.join(getObjectsDirectory, hash))
			File.delete(tempFileName)
			objects << data
		end
	end
	# save off objects json file to a temp file
	tempFileName = File.join(@repoDir, "temp")
	saveDataToJson(tempFileName, objects)
	# get the hash for the temp file, save it as that, and return the hash
	hash = createHash(tempFileName)
	FileUtils.cp(tempFileName, File.join(getObjectsDirectory, hash))
	File.delete(tempFileName)
	return hash
end

#decompress(data) ⇒ Object

decompresses given data



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# File 'lib/tvc.rb', line 381

def decompress(data)
	Zlib::Inflate.inflate(data)
end

#deleteFiles(directoryName) ⇒ Object

recursively deletes all files in the directory.



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# File 'lib/tvc.rb', line 477

def deleteFiles(directoryName)
	Dir.foreach(directoryName) do |dir|
		dirpath = directoryName + '/' + dir
		if File.directory?(dirpath)
			if dir != '.' && dir != '..' && dir != ".tvc"
				deleteFiles(dirpath)
				Dir.delete(dirpath)
			end
		else
			File.delete(dirpath)
		end
	end
end

#findBranch(name) ⇒ Object

find a branch. nil if it does not exist



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# File 'lib/tvc.rb', line 451

def findBranch(name)
	branches = getBranches
	branches.each do |branch|
		if branch["name"] == name
			return branch
		end
	end
	return nil
end

#findChanges(directory, currentHash) ⇒ Object

creates a list of changes made



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# File 'lib/tvc.rb', line 134

def findChanges(directory, currentHash)
	currentData = getDataFromJson(File.join(getObjectsDirectory, currentHash))
	changes = []
	# loop through every item in the directory
	Dir.foreach(directory) do |dirItem|
		if dirItem != '.' && dirItem != '..' && dirItem != ".tvc"
			dirPath = File.join(directory, dirItem)
			foundItem = nil
			itemType = File.directory?(dirPath) ? "tree" : "blob"
			# compare the item to the directory's json
			currentData.each_index do |index|
				currentItem = currentData[index]
				if currentItem["name"] == dirItem && currentItem["type"] == itemType
					foundItem = currentItem
					currentData.delete_at(index)
					break
				end
			end
			# if nothing in the json matched this item, it must be new
			if foundItem.nil?
				newChange = { "type" => "added", "name" => dirPath.gsub(@runDir, "") }
				changes << newChange
				if itemType == "tree"
					newChanges = findChangesInNewDirectory(dirPath)
					newChanges.each do |change|
						changes << change
					end
				end
			# we found a match, so we need to compare it
			else
				# if it's a directory, continue down to find changes in there
				if itemType == "tree"
					newChanges = findChanges(dirPath, foundItem["hash"])
					newChanges.each do |newChange|
						changes << newChange
					end
				# if it's a file, compare the contents
				else
					# this is a really hacky way to do this, but i'm so lazy
					repoData = getFileData(File.join(getObjectsDirectory, foundItem["hash"]))
					repoData = repoData.gsub(/\s/, "")
					fileData = File.open(dirPath) { |f| f.read }
					fileData = fileData.gsub(/\s/, "")
					diffs = Diff::LCS.diff(repoData, fileData)
					modified = false
					diffs.each do |diffArray|
						diffArray.each do |diff|
							if diff.action != "=" && diff.element != ""
								modified = true;
							end
						end
					end
					if modified
						newChange = { "type" => "modified", "name" => dirPath.gsub(@runDir, "") }
						changes << newChange
					end
				end
			end
		end
	end
	# if we still have items in the directory json, they must have been deleted
	currentData.each do |currentItem|
		newChange = { "type" => "deleted", "name" => currentItem["name"] }
		changes << newChange
	end
	return changes
end

#findChangesInNewDirectory(directory) ⇒ Object

returns a list of everything in this directory.



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# File 'lib/tvc.rb', line 203

def findChangesInNewDirectory(directory)
	changes = []
	Dir.foreach(directory) do |dirItem|
		if dirItem != '.' && dirItem != '..' && dirItem != ".tvc"
			dirPath = File.join(directory, dirItem)
			newChange = { "type" => "added", "name" => dirPath.gsub(@runDir, "") }
			changes << newChange
			if File.directory?(dirPath)
				newChanges = findChangesInNewDirectory(dirPath)
				newChanges.each do |change|
					changes << change
				end
			end
		end
	end
	return changes
end

#findCommonAncestor(source, target) ⇒ Object

attempts to find a common parent for the two revisions



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# File 'lib/tvc.rb', line 222

def findCommonAncestor(source, target)
	sourceParentHash = source["hash"]
	versions = getHistoryEntries
	# loop through until we hit the end of the tree for the source
	while not sourceParentHash.nil?
		sourceParent = nil
		targetParentHash = target["hash"]
		versions.each do |version|
			if version["hash"] == sourceParentHash
				sourceParent = version
				break
			end
		end
		# loop through the target tree, hoping we find something that matches up
		while not targetParentHash.nil?
			versions.each do |version|
				if version["hash"] == targetParentHash
					if targetParentHash == sourceParentHash
						return version
					else
						targetParentHash = version["parent"]
					end
				end
			end
		end
		if sourceParent.nil?
			sourceParentHash = nil
		else
			sourceParentHash = sourceParent["parent"]
		end
	end
	return nil
end

#getBranches ⇒ Object

get all branches



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# File 'lib/tvc.rb', line 446

def getBranches
	branches = getDataFromJson(File.join(@repoDir, "pointers"))
end

#getCurrentEntry ⇒ Object

get the entry in the current file



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# File 'lib/tvc.rb', line 441

def getCurrentEntry
	current = (getDataFromJson(File.join(@repoDir, "current")))[0]
end

#getDataFromJson(filePath) ⇒ Object

extracts json data from a given file



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# File 'lib/tvc.rb', line 371

def getDataFromJson(filePath)
	JSON.parse(getFileData(filePath))
end

#getFileData(filePath) ⇒ Object

gets and decompresses a given file



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# File 'lib/tvc.rb', line 376

def getFileData(filePath)
	decompress(File.open(filePath, "rb") { |f| f.read })	
end

#getFullHash(hash) ⇒ Object

gets a full hash if only given a short hash. allows for easier specification of revisions, but can be kind of dangerous if the short hash is too short



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# File 'lib/tvc.rb', line 464

def getFullHash(hash)
	Dir.foreach(getObjectsDirectory) do |dir|
		dirpath = getObjectsDirectory + '/' + dir
		unless File.directory?(dirpath)
			if dir[0, hash.length] == hash
				return dir
			end
		end
	end
	return nil
end

#getHistoryEntries ⇒ Object

retrieves the history entries



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# File 'lib/tvc.rb', line 430

def getHistoryEntries
	history = getDataFromJson(File.join(@repoDir, "history"))
end

#getObjectsDirectory ⇒ Object

returns the path to the objects directory



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# File 'lib/tvc.rb', line 418

def getObjectsDirectory
	return @repoDir + '/' + "objects"
end

#getRepositoryDirectory ⇒ Object

get the repository directory



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# File 'lib/tvc.rb', line 558

def getRepositoryDirectory
	while true
		atRoot = true
		Dir.foreach(Dir.getwd) do |dir|
			if dir == ".tvc"
				@runDir = Dir.getwd
				Dir.chdir(".tvc")
				return Dir.getwd
			end
			if dir == ".."
				atRoot = false
			end
		end
		if atRoot
			Dir.chdir(@runDir)
			return nil
		else
			Dir.chdir("..")
		end
	end
end

#help ⇒ Object

prints a list of valid functions and their uses



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# File 'lib/tvc.rb', line 359

def help
	puts "help - This text"
	puts "init - Initialize a repository"
	puts "commit - Commit changes to a repository"
	puts "branch - Create a new branch.  If not given a branch name, it lists all current branches."
	puts "checkout - Move to the specified branch for modifying"
	puts "replace - Pulls the desired revision down from the repository"
	puts "merge - Merges the specified branch with the current branch"
	puts "status - Prints a list of changes from the current version of the repository"
end

#history ⇒ Object

prints a list of commits up the chain



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# File 'lib/tvc.rb', line 63

def history
	current = getCurrentEntry
	hash = current["hash"]
	versions = getHistoryEntries
	while not hash.nil?
		versions.each do |version|
			if version["hash"] == hash
				puts "#{version["hash"]}\n#{version["message"]}\n\n"
				hash = version["parent"]
				break
			end
		end
	end
end

#init ⇒ Object

initialize a repository



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# File 'lib/tvc.rb', line 25

def init
	Dir.chdir(@runDir)
	Dir.mkdir(".tvc") unless Dir::exists?(".tvc")
	@repoDir = getRepositoryDirectory
	Dir.mkdir(getObjectsDirectory) unless Dir::exists?(getObjectsDirectory)
	saveDataToJson(File.join(@repoDir, "pointers"), [{"name" => "master", "hash" => nil, "parent" => nil}])
	saveDataToJson(File.join(@repoDir, "history"), [])
	saveDataToJson(File.join(@repoDir, "current"), [{"name" => "master", "hash" => nil, "parent" => nil}])
end

#listBranches ⇒ Object

list all existing branches



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# File 'lib/tvc.rb', line 581

def listBranches
	branches = getBranches
	branches.each do |branch|
		puts branch["name"]
	end
end

#merge(branchName) ⇒ Object

merges a branch into the current branch i’m betting this is going to look like crap



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# File 'lib/tvc.rb', line 104

def merge(branchName)
	source = findBranch(branchName)
	target = getCurrentEntry
	parent = findCommonAncestor(source, target)
	if not source.nil?
		if not parent.nil?
			mergeFilesForDirectory(@runDir, source["hash"], target["hash"], parent["hash"])
			commit("Merged branch #{branchName}")
		else
			puts "Could not find common ancestor"
		end
	else
		puts "Branch doesn't exist"
	end
end

#mergeFiles(sourceHash, targetHash, parentHash, targetPath) ⇒ Object

attempt to merge two files together given a common parent this seems like a pretty naive way of doing things, but i’m lazy!



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# File 'lib/tvc.rb', line 306

def mergeFiles(sourceHash, targetHash, parentHash, targetPath)
	sourceData = getFileData(File.join(getObjectsDirectory, sourceHash))
	targetData = getFileData(File.join(getObjectsDirectory, targetHash))
	parentData = getFileData(File.join(getObjectsDirectory, parentHash))
	# get the changes it took to get from the parent to the source
	sourceDiffs = Diff::LCS.diff(parentData, sourceData)
	targetDiffs = Diff::LCS.diff(parentData, targetData)
	# need to modify the source diffs based on the changes between the parent
	# and the target.
	# (this is really hacky and inefficient.  i need to come up with a better 
	# way to do this)
	targetDiffs.each do |targetDiffArray|
		targetDiffArray.each do |targetDiff|
			sourceDiffs.each do |sourceDiffArray|
				sourceDiffArray.each do |sourceDiff|
					if targetDiff.position <= sourceDiff.position
						if targetDiff.action == "-"
							sourceDiff.position -= targetDiff.element.length
						elsif targetDiff.action == "+"
							sourceDiff.position += targetDiff.element.length
						end
					end
				end
			end
		end
	end
	# once we have all the changes between the source and parent, and they've
	# been adjusted by the changes between target and parent, apply the source
	# changes to the target
	mergedData = Diff::LCS.patch!(targetData, sourceDiffs)
	mergedFile = File.open(targetPath, "w")
	mergedFile.write mergedData
	mergedFile.close
end

#mergeFilesForDirectory(directory, sourceHash, targetHash, parentHash) ⇒ Object

attempts to merge the items for the specified directory together



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# File 'lib/tvc.rb', line 257

def mergeFilesForDirectory(directory, sourceHash, targetHash, parentHash)
	sourceJson = getDataFromJson(File.join(getObjectsDirectory, sourceHash))
	targetJson = getDataFromJson(File.join(getObjectsDirectory, targetHash))
	parentJson = getDataFromJson(File.join(getObjectsDirectory, parentHash))
	# for each item in the source, attempt to find a corresponding item in the target
	sourceJson.each do |sourceItem|
		matchingItem = nil
		parentMatch = nil
		targetJson.each do |targetItem|
			if targetItem["name"] == sourceItem["name"] && targetItem["type"] == sourceItem["type"]
				matchingItem = targetItem
				break
			end
		end
		parentJson.each do |parentItem|
			if parentItem["name"] == sourceItem["name"] && parentItem["type"] == sourceItem["type"]
				parentMatch = parentItem
				break
			end
		end
		# we're only going to attempt to merge if we've found some common parent
		# otherwise, we're just going to straight up replace that thing
		if parentMatch.nil?
			puts "No common ancestor found, pushing change to target"
			createItem(directory, sourceItem)
		# if there's no matching item, but there is a parent, well, i guess it got deleted 
		# in the target, but is needed by source.  add it back in.
		elsif matchingItem.nil?
			puts "No matching item found, pushing change to target"
			createItem(directory, sourceItem)
		# if we've got everything we need, we'll attempt to merge
		else
			# if this is a tree, continue on to do all the logic for it
			if sourceItem["type"] == "tree"
				mergeFilesForDirectory(File.join(directory, sourceItem["name"]), sourceItem["hash"], matchingItem["hash"], parentMatch["hash"])
			# if it's a fine, try to merge the two together
			# man, this might fail horribly with binary files.
			# watch out for that
			elsif sourceItem["type"] == "blob"
				if sourceItem["hash"] != matchingItem["hash"]
					mergeFiles(sourceItem["hash"], matchingItem["hash"], parentMatch["hash"], File.join(directory, sourceItem["name"]))
				end
			end
		end
	end
end

#moveFiles(directoryName, jsonInfo) ⇒ Object

gets files from the given json



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# File 'lib/tvc.rb', line 492

def moveFiles(directoryName, jsonInfo)
	jsonInfo.each do |item|
		createItem(directoryName, item)
	end
end

#replace(versionHash) ⇒ Object

replace current files with requested version



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# File 'lib/tvc.rb', line 50

def replace(versionHash)
	hash = getFullHash(versionHash)
	if not hash.nil?
		deleteFiles(@runDir)
		rootInfo = getDataFromJson(File.join(getObjectsDirectory, hash))
		moveFiles(@runDir, rootInfo)
	else
		puts "This version does not exist"
		return
	end
end

#repositoryIssueError ⇒ Object

this was a commonly used error, hence the function just for it.



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# File 'lib/tvc.rb', line 18

def repositoryIssueError
	puts "The repository either has not been initialized 
		or this command is not being run from the base
		directory of the repository".gsub(/\s+/, " ").strip
end

#saveBranches(branches) ⇒ Object

save off all branches



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# File 'lib/tvc.rb', line 553

def saveBranches(branches)
	saveDataToJson(File.join(@repoDir, "pointers"), branches)
end

#saveDataToJson(filePath, data) ⇒ Object

puts data in json format in a given file warning: this will replace all text in the file



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# File 'lib/tvc.rb', line 399

def saveDataToJson(filePath, data)
	saveFileData(filePath, JSON.generate(data))
end

#saveFileData(filePath, data) ⇒ Object

compresses and saves data to a path



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# File 'lib/tvc.rb', line 386

def saveFileData(filePath, data)
	f = File.open(filePath, "wb")
	f.write(compress(data))
	f.close
end

#status ⇒ Object

find and display the changes from the current version in the repository



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# File 'lib/tvc.rb', line 121

def status
	current = getCurrentEntry
	changes = findChanges(@runDir, current["hash"])
	if changes.empty?
		puts "No changes made"
	else
		changes.each do |change|
			puts "#{change["name"]} #{change["type"]}"
		end
	end
end