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|
defmodule Diff do
@moduledoc """
Utilities for comparing build artifacts.
"""
@known_chunks ~w(
abstract_code
debug_info
attributes
compile_info
exports
labeled_exports
imports
indexed_imports
locals
labeled_locals
atoms
)a
@doc """
Compares the build artifacts of two build directories.
"""
@spec compare_dirs(Path.t(), Path.t()) ::
{
only1_paths :: list(Path.t()),
only2_paths :: list(Path.t()),
diff :: list({Path.t(), diff :: String.t()})
}
def compare_dirs(dir1, dir2) do
dir1 = Path.expand(dir1)
dir2 = Path.expand(dir2)
assert_dir!(dir1)
assert_dir!(dir2)
dir1_paths = relative_paths(dir1)
dir2_paths = relative_paths(dir2)
only1_paths = dir1_paths -- dir2_paths
only2_paths = dir2_paths -- dir1_paths
common_paths = dir1_paths -- only1_paths
common_files = Enum.reject(common_paths, &File.dir?/1)
diff =
Enum.flat_map(common_files, fn path ->
file1 = Path.join(dir1, path)
file2 = Path.join(dir2, path)
case compare_files(file1, file2) do
:eq -> []
{:diff, diff} -> [{path, diff}]
end
end)
{only1_paths, only2_paths, diff}
end
@doc """
Compares the contents of two files.
If the files are BEAM files, it performs a more human-friendly
"BEAM-diff".
"""
@spec compare_files(Path.t(), Path.t()) :: :eq | {:diff, diff :: String.t()}
def compare_files(file1, file2) do
content1 = File.read!(file1)
content2 = File.read!(file2)
if content1 == content2 do
:eq
else
diff =
if String.ends_with?(file1, ".beam") do
beam_diff(file1, content1, file2, content2)
else
file_diff(file1, file2)
end
{:diff, diff}
end
end
defp beam_diff(file1, content1, file2, content2) do
with {:ok, {module, chunks1}} <- :beam_lib.chunks(content1, @known_chunks),
{:ok, {^module, chunks2}} <- :beam_lib.chunks(content2, @known_chunks),
true <- chunks1 != chunks2 do
for {chunk1, chunk2} <- Enum.zip(chunks1, chunks2), chunk1 != chunk2 do
tmp_file1 =
chunk1
|> inspect(pretty: true, limit: :infinity)
|> write_tmp()
tmp_file2 =
chunk2
|> inspect(pretty: true, limit: :infinity)
|> write_tmp()
file_diff(tmp_file1, tmp_file2)
end
else
_ ->
file_diff(file1, file2)
end
end
defp file_diff(file1, file2) do
{diff, _} = System.cmd("diff", [file1, file2])
diff
end
defp relative_paths(dir) do
dir
|> Path.join("**")
|> Path.wildcard()
|> Enum.map(&Path.relative_to(&1, dir))
end
defp assert_dir!(dir) do
unless File.dir?(dir) do
raise ArgumentError, "#{inspect(dir)} is not a directory"
end
end
defp write_tmp(content) do
filename = generate_tmp_filename()
File.mkdir_p!("tmp")
File.write!(Path.join("tmp", filename), content)
Path.join("tmp", filename)
end
defp generate_tmp_filename do
sec = :os.system_time(:second)
rand = :rand.uniform(999_999_999)
scheduler_id = :erlang.system_info(:scheduler_id)
"tmp-#{sec}-#{rand}-#{scheduler_id}"
end
end
case System.argv() do
[dir1, dir2] ->
case Diff.compare_dirs(dir1, dir2) do
{[], [], []} ->
IO.puts("#{inspect(dir1)} and #{inspect(dir2)} are equal")
{only1, only2, diff} ->
for path <- only1, do: IO.puts("Only in #{dir1}: #{path}")
for path <- only2, do: IO.puts("Only in #{dir2}: #{path}")
for {path, diff} <- diff, do: IO.puts("Diff #{path}:\n#{diff}")
System.halt(1)
end
_ ->
IO.puts("Please, provide two directories as arguments")
System.halt(1)
end
|
