From 2f4d8ecb7aca1d9254c05aeb144dc4cc936c389b Mon Sep 17 00:00:00 2001
From: Vinicius Ferreira Negrisolo <vinicius.negrisolo@gmail.com>
Date: Sun, 4 Oct 2020 17:29:03 -0400
Subject: [PATCH] Add :disabled pseudo selector

---
 README.md                          |  1 +
 lib/floki/selector.ex              |  4 +++
 lib/floki/selector/pseudo_class.ex | 13 +++++++++
 test/floki_test.exs                | 42 ++++++++++++++++++++++++++++++
 4 files changed, 60 insertions(+)

diff --git a/README.md b/README.md
index 0de8f2c4..4b5aec5b 100644
--- a/README.md
+++ b/README.md
@@ -241,6 +241,7 @@ Here you find all the [CSS selectors](https://www.w3.org/TR/selectors/#selectors
 | E:first-of-type   | an E element, first child of its type among its siblings |
 | E:last-of-type   | an E element, last child of its type among its siblings |
 | E:checked       | An E element (checkbox, radio, or option) that is checked |
+| E:disabled      | An E element (button, input, select, textarea, or option) that is disabled |
 | E.warning       | an E element whose class is "warning" |
 | E#myid          | an E element with ID equal to "myid" |
 | E:not(s)        | an E element that does not match simple selector s |
diff --git a/lib/floki/selector.ex b/lib/floki/selector.ex
index c5b14960..78595ef0 100644
--- a/lib/floki/selector.ex
+++ b/lib/floki/selector.ex
@@ -201,6 +201,10 @@ defmodule Floki.Selector do
     PseudoClass.match_checked?(html_node)
   end
 
+  defp pseudo_class_match?(html_node, %{name: "disabled"}, _tree) do
+    PseudoClass.match_disabled?(html_node)
+  end
+
   defp pseudo_class_match?(html_node, pseudo_class = %{name: "fl-contains"}, tree) do
     PseudoClass.match_contains?(tree, html_node, pseudo_class)
   end
diff --git a/lib/floki/selector/pseudo_class.ex b/lib/floki/selector/pseudo_class.ex
index 8219f34a..18c0fd8c 100644
--- a/lib/floki/selector/pseudo_class.ex
+++ b/lib/floki/selector/pseudo_class.ex
@@ -131,6 +131,19 @@ defmodule Floki.Selector.PseudoClass do
     false
   end
 
+  @disableable_html_nodes ~w[button input select option textarea]
+
+  def match_disabled?(%{type: type} = html_node) when type in @disableable_html_nodes do
+    case List.keyfind(html_node.attributes, "disabled", 0) do
+      {"disabled", _} -> true
+      _ -> false
+    end
+  end
+
+  def match_disabled?(_html_node) do
+    false
+  end
+
   defp node_position(ids, %HTMLNode{node_id: node_id}) do
     {_node_id, position} = Enum.find(ids, fn {id, _} -> id == node_id end)
 
diff --git a/test/floki_test.exs b/test/floki_test.exs
index f352f4be..bf11b30d 100644
--- a/test/floki_test.exs
+++ b/test/floki_test.exs
@@ -986,6 +986,48 @@ defmodule FlokiTest do
            ] = Floki.find(doc, ":checked")
   end
 
+  test "disabled pseudo-class" do
+    doc =
+      document!(
+        html_body(~s"""
+        <button disabled="disabled">button 1</button>
+        <button disabled>button 2</button>
+        <button>button 3</button>
+
+        <input type="text" name="text 1" disabled="disabled">
+        <input type="text" name="text 2" disabled>
+        <input type="text" name="text 3">
+
+        <select name="select 1" disabled="disabled"><option value="option 1">Option 1</option></select>
+        <select name="select 2" disabled><option value="option 2">Option 2</option></select>
+        <select name="select 3"><option value="option 3">Option 3</option></select>
+
+        <select name="select 4"><option value="option 4" disabled="disabled">Option 4</option></select>
+        <select name="select 5"><option value="option 5" disabled>Option 5</option></select>
+        <select name="select 6"><option value="option 6">Option 6</option></select>
+
+        <textarea name="text area 1" disabled="disabled">Text Area 1</textarea>
+        <textarea name="text area 2" disabled>Text Area 2</textarea>
+        <textarea name="text area 3">Text Area 3</textarea>
+        """)
+      )
+
+    assert [
+             {"button", [{"disabled", _}], ["button 1"]},
+             {"button", [{"disabled", _}], ["button 2"]},
+             {"input", [{"type", "text"}, {"name", "text 1"}, {"disabled", _}], []},
+             {"input", [{"type", "text"}, {"name", "text 2"}, {"disabled", _}], []},
+             {"select", [{"name", "select 1"}, {"disabled", _}],
+              [{"option", [{"value", "option 1"}], ["Option 1"]}]},
+             {"select", [{"name", "select 2"}, {"disabled", _}],
+              [{"option", [{"value", "option 2"}], ["Option 2"]}]},
+             {"option", [{"value", "option 4"}, {"disabled", _}], ["Option 4"]},
+             {"option", [{"value", "option 5"}, {"disabled", _}], ["Option 5"]},
+             {"textarea", [{"name", "text area 1"}, {"disabled", _}], ["Text Area 1"]},
+             {"textarea", [{"name", "text area 2"}, {"disabled", _}], ["Text Area 2"]}
+           ] = Floki.find(doc, ":disabled")
+  end
+
   # Floki.find/2 - XML and invalid HTML
 
   test "get elements inside a XML structure" do