dindexer/tools/flat_git.rb

#!/usr/bin/env ruby

=begin
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successors. We intend this dedication to be an overt act of
relinquishment in perpetuity of all present and future rights to this
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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For more information, please refer to <http://unlicense.org/>
=end

require 'shellwords'
require 'pathname'
require 'yaml'

GIT="git"

SubmoduleInfo = Struct.new(:path, :url, :status, :name, :hash)

def call_git(parTokens, parCaptureStdout=true, work_dir: nil)
	git_c_param = ""
	if work_dir then
		raise ScriptError, "Tainted path received in call_git() function" if work_dir.tainted?
		git_c_param = " -C #{work_dir}"
	end

	command_line = ""
	if parTokens.is_a?String then
		raise ScriptError, "Tainted token received in call_git() function" if parTokens.tainted?
		command_line = parTokens
	elsif parTokens.is_a?Array then
		parTokens.each do |tok,idx|
			raise ScriptError, "Tainted token at index #{idx} received in call_git() function" if tok.tainted?
		end
		command_line = parTokens.join(" ")
	else
		raise ScriptError, "Invalid parTokens received in call_git() function"
	end

	if parCaptureStdout then
		return `#{GIT}#{git_c_param} #{command_line}`.chomp
	else
		return Kernel.system("#{GIT}#{git_c_param} #{command_line}")
	end
end

def is_absolute_url?(parUrl)
	return not(/^\.{1,2}\// =~ parUrl)
end

def sanitized(parString)
	retval = Shellwords.escape(parString)
	retval.untaint
	return retval
end

def current_remote_url()
	current_branch = call_git(["rev-parse", "--abbrev-ref", "HEAD"])
	current_remote = call_git(["config", "branch.#{sanitized(current_branch)}.remote"])
	remote_url = call_git(["config", "remote.#{sanitized(current_remote)}.url"])
	return remote_url
end

def submodules_info(parBaseRemoteUrl)
	regex_submodule = /^submodule\.(.+?)\.([^.]+)$/
	submodules = Hash.new{ |hash, key| hash[key] = SubmoduleInfo.new }
	call_git(["config", "--file", ".gitmodules", "--name-only", "--list"]).lines.map(&:chomp).each do |line|
		m = regex_submodule.match(line)
		next if m.nil?

		new_value = call_git(["config", "--file", ".gitmodules", sanitized(line)])
		case m[2]
		when "url" then
			submodules[m[1]].url = is_absolute_url?(new_value) ? new_value : File.join(parBaseRemoteUrl, new_value)
			submodules[m[1]].name = File.basename(new_value, ".git")
		when "path" then
			submodules[m[1]].path = new_value
		end
	end

	regex_status = /^(.)([0-9a-fA-F]{40})\s+(.+?)(?:\s+\(.+\))?$/
	call_git(["submodule", "status"]).lines.map(&:chomp).each do |line|
		m = regex_status.match(line)
		next if m.nil?

		submodules[m[3]].status = m[1]
		submodules[m[3]].hash = m[2]
	end
	return submodules
end

def is_inside_git_repo(parPath)
	reply = call_git("rev-parse --is-inside-work-tree 2> /dev/null || echo false", work_dir: parPath)
	return "true" == reply
end

class FlatGit
	def initialize(parCloneDir)
		unless File.exists?(parCloneDir) && File.directory?(parCloneDir) then
			raise ArgumentError, "Specified path doesn't exist or is not a valid directory"
		end

		if is_inside_git_repo(sanitized(parCloneDir)) then
			raise ArgumentError, "Specified path is invalid because it appears to be inside a git repository"
		end

		@clone_dir_abs = Pathname.new(parCloneDir).realpath
		@clone_dir = parCloneDir
	end

	def clone_submodules()
		inplace_submodules = if File.file?("flat_git.yml") then
			local_settings = YAML.load_file("flat_git.yml")
			lst = local_settings["inplace_submodules"]
			lst = [lst] if lst.is_a?(String)
			lst.is_a?(Array) && lst || Array.new
		else
			Array.new
		end

		submodules_info(current_remote_url()).each_value do |submod|
			next unless submod.status == "-"

			guessed_clone_dir = File.join(@clone_dir, submod.name)
			abs_guessed_clone_dir = File.join(@clone_dir_abs, submod.name)
			if inplace_submodules.include?(submod.name) then
				success = call_git(["submodule", "update", "--init", sanitized(submod.path)], false)
				return false unless success
			else
				if !File.exists?(guessed_clone_dir) || Dir.entries(guessed_clone_dir).empty? then
					success = call_git(["clone", sanitized(submod.url)], false, work_dir: sanitized(@clone_dir_abs))
					return false unless success

					if File.exists?(abs_guessed_clone_dir) && File.directory?(abs_guessed_clone_dir) then
						call_git(["config", "core.worktree", ".."], work_dir: sanitized(abs_guessed_clone_dir))
						call_git(["reset", "--hard", sanitized(submod.hash)], work_dir: sanitized(abs_guessed_clone_dir))

						Dir.chdir(abs_guessed_clone_dir) do |path|
							if File.file?(".gitmodules") then
								success = clone_submodules()
								return false unless success
							end
						end
					else
						raise RuntimeError, "Unable to guess where git just cloned the repo"
					end
				end
				call_git(["submodule", "init", sanitized(submod.path)])
				File.open(File.join(submod.path, ".git"), 'w') {|file| file.puts("gitdir: #{File.join(abs_guessed_clone_dir, ".git")}")}
			end
		end
		return true
	end
end

unless ARGV.length == 1 then
	$stderr.puts "Wrong number of arguments"
	exit 2
end

exit(FlatGit.new(ARGV[0]).clone_submodules() ? 1 : 0)