Use quote fragments to remove duplication and optimize calendar parsing (#7951)

Signed-off-by: José Valim <jose.valim@plataformatec.com.br>

Author: josevalim

lib/elixir/lib/calendar/date.ex

@@ -263,13 +263,13 @@ defmodule Date do
   @spec from_iso8601(String.t(), Calendar.calendar()) :: {:ok, t} | {:error, atom}
   def from_iso8601(string, calendar \\ Calendar.ISO)
 
-  def from_iso8601(<<year::4-bytes, ?-, month::2-bytes, ?-, day::2-bytes>>, calendar) do
-    with {year, ""} <- Integer.parse(year),
-         {month, ""} <- Integer.parse(month),
-         {day, ""} <- Integer.parse(day) do
-      with {:ok, date} <- new(year, month, day, Calendar.ISO), do: convert(date, calendar)
-    else
-      _ -> {:error, :invalid_format}
+  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
+
+  def from_iso8601(unquote(match_date), calendar) when unquote(guard_date) do
+    {year, month, day} = unquote(read_date)
+
+    with {:ok, date} <- new(year, month, day, Calendar.ISO) do
+      convert(date, calendar)
     end
   end
 

lib/elixir/lib/calendar/datetime.ex

@@ -505,48 +505,48 @@ defmodule DateTime do
   @doc since: "1.4.0"
   @spec from_iso8601(String.t(), Calendar.calendar()) ::
           {:ok, t, Calendar.utc_offset()} | {:error, atom}
+
+  @sep [?\s, ?T]
+  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
+  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
+
   def from_iso8601(string, calendar \\ Calendar.ISO) when is_binary(string) do
-    with <<year::4-bytes, ?-, month::2-bytes, ?-, day::2-bytes, sep, rest::binary>> <- string,
-         true <- sep in [?\s, ?T],
-         <<hour::2-bytes, ?:, min::2-bytes, ?:, sec::2-bytes, rest::binary>> <- rest,
-         {year, ""} <- Integer.parse(year),
-         {month, ""} <- Integer.parse(month),
-         {day, ""} <- Integer.parse(day),
-         {hour, ""} <- Integer.parse(hour),
-         {minute, ""} <- Integer.parse(min),
-         {second, ""} <- Integer.parse(sec),
+    with <<unquote(match_date), sep, unquote(match_time), rest::binary>>
+         when unquote(guard_date) and sep in @sep and unquote(guard_time) <- string,
          {microsecond, rest} <- Calendar.ISO.parse_microsecond(rest),
-         {:ok, date} <- Date.new(year, month, day),
-         {:ok, time} <- Time.new(hour, minute, second, microsecond),
-         {:ok, offset} <- parse_offset(rest) do
-      %{year: year, month: month, day: day} = date
-      %{hour: hour, minute: minute, second: second, microsecond: microsecond} = time
-      {_, precision} = microsecond
-
-      datetime =
-        Calendar.ISO.naive_datetime_to_iso_days(
-          year,
-          month,
-          day,
-          hour,
-          minute,
-          second,
-          microsecond
-        )
-        |> apply_tz_offset(offset)
-        |> from_iso_days("Etc/UTC", "UTC", 0, 0, calendar, precision)
-
-      {:ok, %{datetime | microsecond: microsecond}, offset}
+         {offset, ""} <- Calendar.ISO.parse_offset(rest) do
+      {year, month, day} = unquote(read_date)
+      {hour, minute, second} = unquote(read_time)
+
+      cond do
+        not calendar.valid_date?(year, month, day) ->
+          {:error, :invalid_date}
+
+        not calendar.valid_time?(hour, minute, second, microsecond) ->
+          {:error, :invalid_time}
+
+        is_nil(offset) ->
+          {:error, :missing_offset}
+
+        true ->
+          {_, precision} = microsecond
+
+          datetime =
+            Calendar.ISO.naive_datetime_to_iso_days(
+              year,
+              month,
+              day,
+              hour,
+              minute,
+              second,
+              microsecond
+            )
+            |> apply_tz_offset(offset)
+            |> from_iso_days("Etc/UTC", "UTC", 0, 0, calendar, precision)
+
+          {:ok, %{datetime | microsecond: microsecond}, offset}
+      end
     else
-      {:error, reason} -> {:error, reason}
-      _ -> {:error, :invalid_format}
-    end
-  end
-
-  defp parse_offset(rest) do
-    case Calendar.ISO.parse_offset(rest) do
-      {offset, ""} when is_integer(offset) -> {:ok, offset}
-      {nil, ""} -> {:error, :missing_offset}
       _ -> {:error, :invalid_format}
     end
   end

lib/elixir/lib/calendar/iso.ex

@@ -36,6 +36,39 @@ defmodule Calendar.ISO do
 
   @months_in_year 12
 
+  @doc false
+  def __match_date__ do
+    quote do
+      [
+        <<y1, y2, y3, y4, ?-, m1, m2, ?-, d1, d2>>,
+        y1 >= ?0 and y1 <= ?9 and y2 >= ?0 and y2 <= ?9 and y3 >= ?0 and y3 <= ?9 and y4 >= ?0 and
+          y4 <= ?9 and m1 >= ?0 and m1 <= ?9 and m2 >= ?0 and m2 <= ?9 and d1 >= ?0 and d1 <= ?9 and
+          d2 >= ?0 and d2 <= ?9,
+        {
+          (y1 - ?0) * 1000 + (y2 - ?0) * 100 + (y3 - ?0) * 10 + (y4 - ?0),
+          (m1 - ?0) * 10 + (m2 - ?0),
+          (d1 - ?0) * 10 + (d2 - ?0)
+        }
+      ]
+    end
+  end
+
+  @doc false
+  def __match_time__ do
+    quote do
+      [
+        <<h1, h2, ?:, i1, i2, ?:, s1, s2>>,
+        h1 >= ?0 and h1 <= ?9 and h2 >= ?0 and h2 <= ?9 and i1 >= ?0 and i1 <= ?9 and i2 >= ?0 and
+          i2 <= ?9 and s1 >= ?0 and s1 <= ?9 and s2 >= ?0 and s2 <= ?9,
+        {
+          (h1 - ?0) * 10 + (h2 - ?0),
+          (i1 - ?0) * 10 + (i2 - ?0),
+          (s1 - ?0) * 10 + (s2 - ?0)
+        }
+      ]
+    end
+  end
+
   @doc """
   Returns the `t:Calendar.iso_days/0` format of the specified date.
 

lib/elixir/lib/calendar/naive_datetime.ex

@@ -476,20 +476,21 @@ defmodule NaiveDateTime do
     end
   end
 
+  @sep [?\s, ?T]
+  [match_date, guard_date, read_date] = Calendar.ISO.__match_date__()
+  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
+
   def from_iso8601(string, calendar) when is_binary(string) do
-    with <<year::4-bytes, ?-, month::2-bytes, ?-, day::2-bytes, sep, rest::binary>> <- string,
-         true <- sep in [?\s, ?T],
-         <<hour::2-bytes, ?:, min::2-bytes, ?:, sec::2-bytes, rest::binary>> <- rest,
-         {year, ""} <- Integer.parse(year),
-         {month, ""} <- Integer.parse(month),
-         {day, ""} <- Integer.parse(day),
-         {hour, ""} <- Integer.parse(hour),
-         {min, ""} <- Integer.parse(min),
-         {sec, ""} <- Integer.parse(sec),
+    with <<unquote(match_date), sep, unquote(match_time), rest::binary>>
+         when unquote(guard_date) and sep in @sep and unquote(guard_time) <- string,
          {microsec, rest} <- Calendar.ISO.parse_microsecond(rest),
          {_offset, ""} <- Calendar.ISO.parse_offset(rest) do
-      with {:ok, utc_date} <- new(year, month, day, hour, min, sec, microsec, Calendar.ISO),
-           do: convert(utc_date, calendar)
+      {year, month, day} = unquote(read_date)
+      {hour, min, sec} = unquote(read_time)
+
+      with {:ok, utc_date} <- new(year, month, day, hour, min, sec, microsec, Calendar.ISO) do
+        convert(utc_date, calendar)
+      end
     else
       _ -> {:error, :invalid_format}
     end

lib/elixir/lib/calendar/time.ex

@@ -221,23 +221,22 @@ defmodule Time do
     from_iso8601(<<h, rest::binary>>, calendar)
   end
 
-  def from_iso8601(<<hour::2-bytes, ?:, min::2-bytes, ?:, sec::2-bytes, rest::binary>>, calendar) do
-    with {hour, ""} <- Integer.parse(hour),
-         {min, ""} <- Integer.parse(min),
-         {sec, ""} <- Integer.parse(sec),
+  [match_time, guard_time, read_time] = Calendar.ISO.__match_time__()
+
+  def from_iso8601(string, calendar) do
+    with <<unquote(match_time), rest::binary>> when unquote(guard_time) <- string,
          {microsec, rest} <- Calendar.ISO.parse_microsecond(rest),
          {_offset, ""} <- Calendar.ISO.parse_offset(rest) do
-      with {:ok, utc_time} <- new(hour, min, sec, microsec, Calendar.ISO),
-           do: convert(utc_time, calendar)
+      {hour, min, sec} = unquote(read_time)
+
+      with {:ok, utc_time} <- new(hour, min, sec, microsec, Calendar.ISO) do
+        convert(utc_time, calendar)
+      end
     else
       _ -> {:error, :invalid_format}
     end
   end
 
-  def from_iso8601(<<_::binary>>, _calendar) do
-    {:error, :invalid_format}
-  end
-
   @doc """
   Parses the extended "Local time" format described by
   [ISO 8601:2004](https://en.wikipedia.org/wiki/ISO_8601).