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Speed up attribute lookup #651

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Speed up attribute lookup #651

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51 changes: 33 additions & 18 deletions lib/floki/selector/attribute_selector.ex
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Original file line number Diff line number Diff line change
Expand Up @@ -59,12 +59,16 @@ defmodule Floki.Selector.AttributeSelector do

def match?(attributes, s = %AttributeSelector{match_type: :includes, flag: "i"}) do
selector_value = String.downcase(s.value)

s.attribute
|> get_value(attributes)
# Splits by whitespaces ("a b c" -> ["a", "b", "c"])
|> String.split([" ", "\t", "\n"], trim: true)
|> Enum.any?(fn v -> String.downcase(v) == selector_value end)
attribute_value = get_value(s.attribute, attributes)

if String.contains?(String.downcase(attribute_value), selector_value) do
attribute_value
# Splits by whitespaces ("a b c" -> ["a", "b", "c"])
|> String.split([" ", "\t", "\n"], trim: true)
|> Enum.any?(fn v -> String.downcase(v) == selector_value end)
else
false
end
end

def match?(attributes, s = %AttributeSelector{match_type: :dash_match, flag: "i"}) do
Expand Down Expand Up @@ -102,9 +106,15 @@ defmodule Floki.Selector.AttributeSelector do
end

def match?(attributes, s = %AttributeSelector{match_type: :includes, value: value}) do
get_value(s.attribute, attributes)
|> String.split([" ", "\t", "\n"], trim: true)
|> Enum.member?(value)
attribute_value = get_value(s.attribute, attributes)

if String.contains?(attribute_value, value) do
attribute_value
|> String.split([" ", "\t", "\n"], trim: true)
|> Enum.member?(value)
else
false
end
end

def match?(attributes, s = %AttributeSelector{match_type: :dash_match}) do
Expand All @@ -125,17 +135,22 @@ defmodule Floki.Selector.AttributeSelector do
s.attribute |> get_value(attributes) |> String.contains?(s.value)
end

defp get_value(attr_name, attributes) do
Enum.find_value(attributes, "", fn
defp get_value(attr_name, attributes) when is_list(attributes) do
case List.keyfind(attributes, attr_name, 0) do
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@philss philss Dec 19, 2025

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How much of the improvements came from this change?

If is not that much, I would prefer to keep the Enum.find_value/3 just because it's easier to read and maintain.

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@preciz preciz Dec 19, 2025 •
edited
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I just ran the benchmarks back and forth changing this part only and it's faster in all cases, the biggest win in speedup is that it's ~11% faster in the "exact_attribute" case but most significantly it halves the memory usage in the "exact_attribute" and in the "attribute_includes" cases.

I believe this library is used heavily by a lot of companies where every speedup has a huge effect on throughput.
That is the case for our company.

{^attr_name, value} -> value
_ -> false
end)
nil -> ""
end
end

defp get_value(attr_name, attributes) when is_map(attributes) do
Map.get(attributes, attr_name, "")
end

defp attribute_present?(name, attributes) when is_list(attributes) do
List.keymember?(attributes, name, 0)
end

defp attribute_present?(name, attributes) do
Enum.any?(attributes, fn
{^name, _v} -> true
_ -> false
end)
defp attribute_present?(name, attributes) when is_map(attributes) do
Map.has_key?(attributes, name)
end
end
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