Installer for SEE

SEE Downloader.lua

--JSON functions
--Credit goes to http://www.computercraft.info/forums2/index.php?/topic/5854-json-api-v201-for-computercraft/
------------------------------------------------------------------ utils
local controls = {["\n"]="\\n", ["\r"]="\\r", ["\t"]="\\t", ["\b"]="\\b", ["\f"]="\\f", ["\""]="\\\"", ["\\"]="\\\\"}


local whites = {['\n']=true; ['r']=true; ['\t']=true; [' ']=true; [',']=true; [':']=true}
function removeWhite(str)
	while whites[str:sub(1, 1)] do
		str = str:sub(2)
	end
	return str
end

------------------------------------------------------------------ decoding

function jsonParseBoolean(str)
	if str:sub(1, 4) == "true" then
		return true, removeWhite(str:sub(5))
	else
		return false, removeWhite(str:sub(6))
	end
end

function jsonParseNull(str)
	return nil, removeWhite(str:sub(5))
end

local numChars = {['e']=true; ['E']=true; ['+']=true; ['-']=true; ['.']=true}
function jsonParseNumber(str)
	local i = 1
	while numChars[str:sub(i, i)] or tonumber(str:sub(i, i)) do
		i = i + 1
	end
	local val = tonumber(str:sub(1, i - 1))
	str = removeWhite(str:sub(i))
	return val, str
end

function jsonParseString(str)
	local i,j = str:find('^".-[^\\]"')
	local s = str:sub(i + 1,j - 1)

	for k,v in pairs(controls) do
		s = s:gsub(v, k)
	end
	str = removeWhite(str:sub(j + 1))
	return s, str
end

function jsonParseArray(str)
	str = removeWhite(str:sub(2))
	
	local val = {}
	local i = 1
	while str:sub(1, 1) ~= "]" do
		local v = nil
		v, str = jsonParseValue(str)
		val[i] = v
		i = i + 1
		str = removeWhite(str)
	end
	str = removeWhite(str:sub(2))
	return val, str
end

function jsonParseObject(str)
	str = removeWhite(str:sub(2))
	
	local val = {}
	while str:sub(1, 1) ~= "}" do
		local k, v = nil, nil
		k, v, str = jsonParseMember(str)
		val[k] = v
		str = removeWhite(str)
	end
	str = removeWhite(str:sub(2))
	return val, str
end

function jsonParseMember(str)
	local k = nil
	k, str = jsonParseValue(str)
	local val = nil
	val, str = jsonParseValue(str)
	return k, val, str
end

function jsonParseValue(str)
	local fchar = str:sub(1, 1)
	if fchar == "{" then
		return jsonParseObject(str)
	elseif fchar == "[" then
		return jsonParseArray(str)
	elseif tonumber(fchar) ~= nil or numChars[fchar] then
		return jsonParseNumber(str)
	elseif str:sub(1, 4) == "true" or str:sub(1, 5) == "false" then
		return jsonParseBoolean(str)
	elseif fchar == "\"" then
		return jsonParseString(str)
	elseif str:sub(1, 4) == "null" then
		return jsonParseNull(str)
	end
	return nil
end

function jsonDecode(str)
	str = removeWhite(str)
	t = jsonParseValue(str)
	return t
end

function downloadJson(url)
	local file = http.get(url)
	if not file then
		return nil
	end
	return jsonDecode(file.readAll())
end

--Settings
local GitHubRepo = "Yevano/see" -- Change to user/repo
local GitHubBranch = "master"	-- Change to needed branch
local installPath = "/see"

--Other settings
local GitHubRef = "refs/heads/"..GitHubBranch
local GitHubRaw = 'https://raw.github.com/'..GitHubRepo..'/'..GitHubBranch..'/'
local args = {...}

--Files to not download
local blacklist = {
	'.gitignore',
	'README.md'
}

function isBlacklisted(path)
	for i, item in ipairs(blacklist) do
		if item == path then
			return true
		end
	end
	return false
end

--List of failed files
local failed = {}

--Download file/create directory or queue to failed queue
function downloadBlob(v)
	if isBlacklisted(v.path) then
			return
	end
	--Make dir if needed
	if v.type == 'tree' then
		fs.makeDir(installPath..v.path)
	else
		--Start download
		local url = (GitHubRaw..v.path):gsub(' ','%%20')
		local f = http.get(url)

		--If couldn't download then add to failed
		if not f then
			table.insert(failed,v)
			return
		end

		--Write file
		local h = fs.open(installPath..v.path, 'w')
		h.write(f.readAll())
		h.close()
	end
end

--Fail and prompt for retry
local function fail(err)
	printError(err)

	while true do
		write("Retry installation? (y/n): ")
		local response = read()
		if string.lower(response):gsub("%s", "") == "y" then
			return true
		elseif string.lower(response):gsub("%s", "") == "n" then
			return false
		end
		print("Invalid input.")
	end
end

--Get install directory
while true do
	if #args == 1 then
		installPath = args[1]
	else
		write("Choose an install path: ")
		installPath = "/" .. shell.resolve(read())
	end

	local configHandle = fs.open("/.see", "w")
	configHandle.write('install_dir = "' .. installPath .. '/see"')
	configHandle.close()

	local suc, err = pcall(fs.makeDir, installPath)
	if not suc then
		if not fail("Could not create installation directory.") then error("Exiting") end
	else
		break
	end
end

installPath = installPath .. '/'
local tree = {}
local latestSha = ''

--Get latest commit
while true do
	--Get sha for specific branch
	local refs = downloadJson('https://api.github.com/repos/'..GitHubRepo..'/git/refs')

	if refs == nil then
		if not fail("Could not fetch branches") then error("Exiting") end
	else
		for i, v in ipairs(refs) do
			if v.ref == GitHubRef then
				latestSha = v.object.sha
				break
			end
		end
		break
	end
end
--Get tree
while true do 
	--Download file list
	tree = downloadJson('https://api.github.com/repos/'..GitHubRepo..'/git/trees/'..latestSha..'?recursive=1').tree

	if tree == nil then
		if not fail("Could not fetch tree") then error("Exiting") end
	else
		break
	end
end

--Prepare file download
local downloads = {}
for i, v in ipairs(tree) do
	table.insert(downloads, function()downloadBlob(v)end)
end

while true do
	parallel.waitForAll(unpack(downloads))

	if #failed > 0 then
		if not fail("Not all files downloaded. Retry?") then error("Exiting") end

		downloads = {}
		for i, v in ipairs(failed) do
			print("Retrying "..v.path)
			table.insert(downloads, function()downloadBlob(v)end)
		end
		failed = {}
	else
		break
	end	
end