76 lines
2 KiB
Elixir
Executable file
76 lines
2 KiB
Elixir
Executable file
#!/usr/bin/env elixir
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defmodule TimestampRestorer do
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@environment System.get_env("MIX_ENV", "dev")
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@db_path "_build/#{@environment}/timestamp-database"
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def sha_all do
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timestamp_database = load_timestamp_database()
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"**/*.{ex,exs,beam}"
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|> Path.wildcard()
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|> Enum.reduce(%{}, fn filename, acc ->
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{sha, timestamp} = process(filename, timestamp_database)
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Map.put(acc, sha, timestamp)
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end)
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|> write_timestamp_database()
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end
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defp load_timestamp_database() do
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if File.exists?(@db_path) do
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@db_path
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|> File.read!()
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|> String.split("\n")
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|> Enum.reduce(%{}, fn line, acc ->
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[sha, timestamp_string] = String.split(line, ":")
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{timestamp, ""} = Integer.parse(timestamp_string)
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Map.put(acc, sha, timestamp)
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end)
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else
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%{}
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end
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end
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defp write_timestamp_database(database) do
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File.mkdir_p!(Path.dirname(@db_path))
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database
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|> Enum.map(fn {key, value} -> "#{key}:#{value}" end)
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|> Enum.join("\n")
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|> (& File.write!(@db_path, &1)).()
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end
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defp process(filename, timestamp_database) do
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sha = sha(filename)
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{:ok, %{mtime: new_timestamp}} = File.lstat(filename, time: :posix)
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case Map.get(timestamp_database, sha) do
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nil ->
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:logger.debug("[NEW SHA ] #{filename}: #{new_timestamp}")
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timestamp when timestamp < new_timestamp ->
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:logger.debug("[RESTORED ] #{filename}: #{timestamp}")
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File.touch(filename, timestamp)
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timestamp when timestamp >= new_timestamp ->
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:logger.debug("[UNCHANGED] #{filename}: #{timestamp}")
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end
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{sha, new_timestamp}
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end
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defp sha(filename) do
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hash_ref = :crypto.hash_init(:sha)
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File.stream!(filename)
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|> Enum.reduce(hash_ref, fn chunk, prev_ref->
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new_ref = :crypto.hash_update(prev_ref, chunk)
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new_ref
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end)
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|> :crypto.hash_final()
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|> Base.encode16()
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|> String.downcase()
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end
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end
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{time, _result} = :timer.tc(TimestampRestorer, :sha_all, [])
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:logger.info("Restored timestamps in #{time / 1_000_000}s")
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