From daff30c4929d086823e11c9bd228febb9cfd3737 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arb=C3=ABr=20Shabhasa?= <ashabhasa@users.noreply.github.com>
Date: Thu, 4 Jul 2024 06:57:43 +0200
Subject: [PATCH] Handle closing tag with whitespace (#128)

---
 lib/saxy/parser/builder.ex | 29 +++++++++++++++++------------
 test/saxy_test.exs         | 18 ++++++++++++++++++
 2 files changed, 35 insertions(+), 12 deletions(-)

diff --git a/lib/saxy/parser/builder.ex b/lib/saxy/parser/builder.ex
index 2e7d7ad..b11ad28 100644
--- a/lib/saxy/parser/builder.ex
+++ b/lib/saxy/parser/builder.ex
@@ -851,7 +851,7 @@ defmodule Saxy.Parser.Builder do
             open_tag_name(rest, more?, original, pos, state, Utils.compute_char_len(codepoint))
 
           "/" <> rest ->
-            close_tag_name(rest, more?, original, pos + 1, state, 0)
+            close_tag_name(rest, more?, original, pos + 1, state, 0, 0)
 
           "![CDATA[" <> rest ->
             element_cdata(rest, more?, original, pos + 8, state, 0)
@@ -1161,30 +1161,31 @@ defmodule Saxy.Parser.Builder do
         end
       end
 
-      defp close_tag_name(<<buffer::bits>>, more?, original, pos, state, 0) do
+      defp close_tag_name(<<buffer::bits>>, more?, original, pos, state, 0, 0) do
         lookahead buffer, @streaming do
           char <> rest when is_ascii_name_start_char(char) ->
-            close_tag_name(rest, more?, original, pos, state, 1)
+            close_tag_name(rest, more?, original, pos, state, 1, 1)
 
           token in unquote(utf8_binaries()) when more? ->
-            halt!(close_tag_name(token, more?, original, pos, state, 0))
+            halt!(close_tag_name(token, more?, original, pos, state, 0, 0))
 
           <<codepoint::utf8>> <> rest when is_utf8_name_start_char(codepoint) ->
-            close_tag_name(rest, more?, original, pos, state, Utils.compute_char_len(codepoint))
+            len = Utils.compute_char_len(codepoint)
+            close_tag_name(rest, more?, original, pos, state, len, len)
 
           _ in [""] when more? ->
-            halt!(close_tag_name("", more?, original, pos, state, 0))
+            halt!(close_tag_name("", more?, original, pos, state, 0, 0))
 
           _ ->
             Utils.parse_error(original, pos, state, {:token, :end_tag})
         end
       end
 
-      defp close_tag_name(<<buffer::bits>>, more?, original, pos, state, len) do
+      defp close_tag_name(<<buffer::bits>>, more?, original, pos, state, len, copy_to) do
         lookahead buffer, @streaming do
           ">" <> rest ->
             [open_tag | stack] = state.stack
-            ending_tag = binary_part(original, pos, len)
+            ending_tag = binary_part(original, pos, copy_to)
             pos = pos + len + 1
 
             if open_tag == ending_tag do
@@ -1205,16 +1206,20 @@ defmodule Saxy.Parser.Builder do
             end
 
           char <> rest when is_ascii_name_char(char) ->
-            close_tag_name(rest, more?, original, pos, state, len + 1)
+            close_tag_name(rest, more?, original, pos, state, len + 1, copy_to + 1)
+
+          char <> rest when is_whitespace(char) ->
+            close_tag_name(rest, more?, original, pos, state, len + 1, copy_to)
 
           token in unquote(utf8_binaries()) when more? ->
-            halt!(close_tag_name(token, more?, original, pos, state, len))
+            halt!(close_tag_name(token, more?, original, pos, state, len, copy_to))
 
           <<codepoint::utf8>> <> rest when is_utf8_name_char(codepoint) ->
-            close_tag_name(rest, more?, original, pos, state, len + Utils.compute_char_len(codepoint))
+            char_len = Utils.compute_char_len(codepoint)
+            close_tag_name(rest, more?, original, pos, state, len + char_len, copy_to + char_len)
 
           _ in [""] when more? ->
-            halt!(close_tag_name("", more?, original, pos, state, len))
+            halt!(close_tag_name("", more?, original, pos, state, len, copy_to))
 
           _ ->
             Utils.parse_error(original, pos + len, state, {:token, :end_tag})
diff --git a/test/saxy_test.exs b/test/saxy_test.exs
index 4242b75..981b662 100644
--- a/test/saxy_test.exs
+++ b/test/saxy_test.exs
@@ -73,6 +73,20 @@ defmodule SaxyTest do
            ]
   end
 
+  test "parse_string/4 parses XML binary with closing tags containing whitespaces" do
+    data = "<foo>Some data</foo    >"
+
+    assert {:ok, state} = parse(data, StackHandler, [])
+
+    assert state == [
+             end_document: {},
+             end_element: "foo",
+             characters: "Some data",
+             start_element: {"foo", []},
+             start_document: []
+           ]
+  end
+
   test "handles trailing Unicode codepoints during streaming" do
     data = "<foo>𠜎𠜱𠝹𠱓</foo>"
     stream = for byte <- :binary.bin_to_list(data), do: <<byte>>
@@ -134,6 +148,10 @@ defmodule SaxyTest do
     data = "<foo><bar></bee></foo>"
     assert {:error, exception} = parse(data, StackHandler, [])
     assert Exception.message(exception) == "unexpected ending tag \"bee\", expected tag: \"bar\""
+
+    data = "<foo>Some data</foo    bar >"
+    assert {:error, exception} = parse(data, StackHandler, [])
+    assert Exception.message(exception) == "unexpected ending tag \"foo   \", expected tag: \"foo\""
   end
 
   describe "encode!/2" do