pkg: Formatting of package status

Functions to format the status block for a single package.

src/lib/autoload/a_05_backend.lua

@@ -95,6 +95,69 @@ function block_parse(block)
 	return result
 end
 
+--[[
+Format single block of data.
+The block shall be passed as an array, each item an object with header and value strings.
+The object may be an empty table. In that case, no output is generated for the given
+object.
+]]
+function block_dump_ordered(block)
+	return table.concat(utils.map(block, function (i, line)
+		if line.header then
+			local space = ' '
+			if line.value:match("^%s") then
+				space = ''
+			end
+			return i, line.header .. ":" .. space .. line.value .. "\n"
+		else
+			return i, ''
+		end
+	end))
+end
+
+--[[
+Dump status of a single package.
+]]
+function pkg_status_dump(status)
+	local function line(name, conversion)
+		if status[name] then
+			return {header = name, value = conversion(status[name])}
+		else
+			return {}
+		end
+	end
+	local function raw(name)
+		return line(name, function (v) return v end)
+	end
+	return block_dump_ordered({
+		raw "Package",
+		raw "Version",
+		line("Depends", function (deps)
+			-- Join the dependencies together, separated by commas
+			return table.concat(deps, ', ')
+		end),
+		raw "Conflicts",
+		line("Status", function (status)
+			-- Join status flags together, separated by spaces
+			return table.concat(utils.set2arr(status), ' ')
+		end),
+		raw "Architecture",
+		line("Conffiles", function (confs)
+			local i = 0
+			--[[
+			For each dep, place it into an array instead of map and format the line.
+			Then connect these lines together with newlines.
+			]]
+			return "\n" .. table.concat(utils.map(confs, function (filename, hash)
+				i = i + 1
+				return i, " " .. filename .. " " .. hash
+			end), "\n")
+		end),
+		raw "Installed-Time",
+		raw "Auto-Installed"
+	})
+end
+
 --[[
 Split text into blocks separated by at least one empty line.
 Returns an iterator.

tests/backend.lua

@@ -423,6 +423,97 @@ function test_collisions()
 	}, rem)
 end
 
+function test_block_dump_ordered()
+	-- Empty block should produce empty output
+	assert_equal('', B.block_dump_ordered({}))
+	-- An ordinary block, nothing special
+	assert_equal(
+[[
+Header: value
+Header2: value2
+]], B.block_dump_ordered({
+		{ header = "Header", value = "value" },
+		{ header = "Header2", value = "value2" }
+	}))
+	-- Repeated headers. Not that we would actually need that in practice.
+	assert_equal(
+[[
+Header: value
+Header: value
+]], B.block_dump_ordered({
+		{ header = "Header", value = "value" },
+		{ header = "Header", value = "value" }
+	}))
+	-- An empty object generates nothing
+	assert_equal(
+[[
+Header: value
+Header: value
+]], B.block_dump_ordered({
+		{ header = "Header", value = "value" },
+		{},
+		{ header = "Header", value = "value" }
+	}))
+	-- A multi-line value
+	assert_equal(
+[[
+Header:
+ value
+ another line
+]], B.block_dump_ordered({
+		{ header = "Header", value =
+-- Since lua eats the first newline directly after [[, we need to provide two.
+[[
+
+ value
+ another line]]}}))
+end
+
+function test_pkg_status_dump()
+	-- Simple package with just one-line headers
+	assert_equal(
+[[
+Package: pkg-name
+Version: 1
+Installed-Time: 1
+]], B.pkg_status_dump({
+	Package = "pkg-name",
+	Version = "1",
+	["Installed-Time"] = "1"
+	}))
+	-- Package with some extra (unused) headers
+	assert_equal(
+[[
+Package: pkg-name
+Version: 1
+Installed-Time: 1
+]], B.pkg_status_dump({
+	Package = "pkg-name",
+	Version = "1",
+	["Installed-Time"] = "1",
+	Extra = "xxxx"
+	}))
+	-- Package with more complex headers
+	assert_equal(
+[[
+Package: pkg-name
+Version: 1
+Depends: dep1, dep2
+Status: flag
+Conffiles:
+ file 1234567890123456
+Installed-Time: 1
+]], B.pkg_status_dump({
+	Package = "pkg-name",
+	Version = "1",
+	["Installed-Time"] = "1",
+	Extra = "xxxx",
+	Depends = { "dep1", "dep2" },
+	Status = { flag = true },
+	Conffiles = { ["file"] = "1234567890123456" }
+	}))
+end
+
 function setup()
 	local sdir = os.getenv("S") or "."
 	-- Use a shortened version of a real status file for tests