From 91e85f9809ed406d2120e424aaa2f249ee18e2c2 Mon Sep 17 00:00:00 2001
From: Aki <please@ignore.pl>
Date: Mon, 1 Jan 2024 23:07:21 +0100
Subject: Implemented first and easy part of reading package lists

---
 Makefile           |  4 ++++
 ensure.lua         | 10 +++++++++
 ensure/list.lua    | 55 ++++++++++++++++++++++++++++++++++++++++++++++++
 spec/list_spec.lua | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 131 insertions(+)
 create mode 100644 Makefile
 create mode 100644 ensure.lua
 create mode 100644 ensure/list.lua
 create mode 100644 spec/list_spec.lua

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..beb6190
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,4 @@
+test:
+	busted
+
+.PHONY: test
diff --git a/ensure.lua b/ensure.lua
new file mode 100644
index 0000000..0dd264b
--- /dev/null
+++ b/ensure.lua
@@ -0,0 +1,10 @@
+#!/usr/bin/env lua
+local l = require "ensure.list"
+local loud = {
+	identifier = l.default.identifier,
+	invalid = function (_, name) io.stderr:write(string.format("invalid package name: %q\n", name)) end,
+}
+local p = l.all(arg[1] or os.getenv("ENSURE") or "/etc/ensure.d", loud)
+for _, name in pairs(p) do
+	print(name)
+end
diff --git a/ensure/list.lua b/ensure/list.lua
new file mode 100644
index 0000000..b38a62f
--- /dev/null
+++ b/ensure/list.lua
@@ -0,0 +1,55 @@
+local dir = require "pl.dir"
+local lpeg = require "lpeg"
+
+local list = {}
+
+
+local function apply (state, method, ...)
+	if state[method] then
+		return state[method](state, ...)
+	end
+	return nil
+end
+
+
+local first = lpeg.R"az" + lpeg.R"09" + lpeg.S"@+_"
+local rest = first + lpeg.S".-"
+local space = lpeg.S" \t\n\r"
+local boundary = #(space + lpeg.P(-1))
+local identifier = lpeg.Cc"identifier" * lpeg.C(first * rest^0) * boundary
+local invalid = lpeg.Cc"invalid" * lpeg.C((1 - space)^1) * boundary
+local entry = lpeg.Carg(1) * (identifier + invalid) / apply
+local packages = space^0 * lpeg.Ct((entry * (space^1 * entry)^0)^-1) * space^0 * -lpeg.P(1)
+-- TODO: Comments?
+list.default = {
+	identifier = function (self, name) return name end,
+	invalid = function (self, text) end,
+}
+
+
+function list.read (text, handler)
+	handler = handler or list.default
+	return packages:match(text, nil, handler)
+end
+
+
+function list.all (dirpath, handler)
+	local all = {}
+	local lists = dir.getfiles(dirpath, "*.list")
+	for _, path in pairs(lists) do
+		local handle = io.open(path)
+		local packages = list.read(handle:read"a", handler)
+		handle:close()
+		if packages then
+			for _, name in pairs(packages) do
+				table.insert(all, name)
+			end
+		else
+			error(string.format("invalid packages list: %s", config))
+		end
+	end
+	return all
+end
+
+
+return list
diff --git a/spec/list_spec.lua b/spec/list_spec.lua
new file mode 100644
index 0000000..d7b5889
--- /dev/null
+++ b/spec/list_spec.lua
@@ -0,0 +1,62 @@
+local list = require "ensure.list"
+
+
+local function handler_with_errors ()
+	local errors = {}
+	local handler = {
+		identifier = function (_, name)
+			return name
+		end,
+		invalid = function (_, text)
+			table.insert(errors, text)
+		end,
+	}
+	return handler, errors
+end
+
+
+describe("List reader", function()
+	it("should translate empty file into an empty table", function()
+		assert.are.same({}, list.read"")
+	end)
+
+	it("should match valid package names", function()
+		local samples = {"name", "@name", "+name", "_name", "name-1.45"}
+		for _, name in pairs(samples) do
+			assert.are.same({name}, list.read(name))
+		end
+	end)
+
+	it("should split package names on whitespace", function()
+		assert.are.same(
+			{"one", "two", "three", "four", "five"},
+			list.read [[one two	three
+			four    	five]]
+		)
+	end)
+
+	it("should ignore leading and trailing whitespace", function()
+		assert.are.same({"name"}, list.read"  name  ")
+	end)
+
+	it("should not match invalid package names", function()
+		assert.are.same({}, list.read".hey")
+		assert.are.same({}, list.read"a=3")
+	end)
+
+	it("should allow custom handlers", function()
+		local handler = {}
+		stub(handler, "identifier")
+		stub(handler, "invalid")
+		local _ = list.read("correct .incorrect", handler)
+		assert.stub(handler.identifier).was.called()
+		assert.stub(handler.invalid).was.called()
+	end)
+
+	it("should match valid and invalid names together", function()
+		local handler, errors = handler_with_errors()
+		local output = list.read("correct .incorrect another -and-not", handler)
+		assert.are.same({"correct", "another"}, output)
+		assert.are.same({".incorrect", "-and-not"}, errors)
+	end)
+end)
-- 
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