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HtmlFilter: support stripping mx-reply elements; modernise code
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@KitsuneRal
KitsuneRal committed Dec 30, 2024
1 parent 7de24de commit e9c42c1
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Showing 2 changed files with 61 additions and 57 deletions.
102 changes: 52 additions & 50 deletions client/htmlfilter.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,14 +18,14 @@
using namespace std;
using namespace Qt::StringLiterals;

namespace HtmlFilter {
namespace {
using namespace HtmlFilter;

enum Mode : unsigned char { QtToMatrix, MatrixToQt, GenericToQt };

class Processor {
public:
[[nodiscard]] static Result process(QString html, Mode mode,
QuaternionRoom* context,
[[nodiscard]] static Result process(QString html, Mode mode, QuaternionRoom* context,
Options options = Default);

private:
Expand All @@ -47,7 +47,7 @@ class Processor {
void filterText(QString& text);
};

static const auto permittedTags = std::to_array<QStringView>(
constexpr auto permittedTags = std::to_array<QStringView>(
{ u"font", u"del", u"h1", u"h2", u"h3", u"h4", u"h5", u"h6",
u"blockquote", u"p", u"a", u"ul", u"ol", u"sup", u"sub", u"li",
u"b", u"i", u"u", u"strong", u"em", u"s", u"code", u"hr",
Expand All @@ -60,25 +60,24 @@ struct PassList {
};

// See filterTag() on special processing of commented out tags/attributes
static const PassList passLists[] = {
{ u"a", { u"name", u"target", /* "href" - only from permittedSchemes */ } },
{ u"img", { u"width", u"height", u"alt", u"title", u"data-mx-emoticon"
/* "src" - only 'mxc:' */ } },
const auto passLists = std::to_array<PassList>({
{ u"a", { u"name", u"target", /* u"href" - only from permittedSchemes */ } },
{ u"img",
{ u"width", u"height", u"alt", u"title", u"data-mx-emoticon", /* u"src" - only 'mxc:' */ } },
{ u"ol", { u"start" } },
{ u"font", { u"color", u"data-mx-color", u"data-mx-bg-color" } },
{ u"span", { u"color", u"data-mx-color", u"data-mx-bg-color" } }
//, { "code", { "class" /* must start with 'language-' */ } } // Special case
};
{ u"span", { u"color", u"data-mx-color", u"data-mx-bg-color" } },
// { u"code", { u"class" /* must start with 'language-' */ } }
});

static QStringView const permittedSchemes[]{
u"http:", u"https:", u"ftp:", u"mailto:",
u"magnet:", u"matrix:", u"mxc:" /* MSC2398 */
};
constexpr auto permittedSchemes = std::to_array<QStringView>({
u"http:", u"https:", u"ftp:", u"mailto:", u"magnet:", u"matrix:", u"mxc:" /* MSC2398 */
});

static const auto htmlColorAttr = u"color";
static const auto htmlStyleAttr = u"style";
static const auto mxColorAttr = u"data-mx-color";
static const auto mxBgColorAttr = u"data-mx-bg-color";
constexpr auto htmlColorAttr = u"color";
constexpr auto htmlStyleAttr = u"style";
constexpr auto mxColorAttr = u"data-mx-color";
constexpr auto mxBgColorAttr = u"data-mx-bg-color";

[[nodiscard]] QString mergeMarkdown(const QString& html)
{
Expand Down Expand Up @@ -333,37 +332,6 @@ Result Processor::process(QString html, Mode mode, QuaternionRoom* context,
return { resultHtml.trimmed(), p.errorPos, p.errorString };
}

QString toMatrixHtml(const QString& qtMarkup, QuaternionRoom* context,
Options options)
{
// Validation of HTML emitted by Qt doesn't make much sense
Q_ASSERT(!options.testFlag(Validate));
const auto& result =
Processor::process(qtMarkup, QtToMatrix, context, options);
Q_ASSERT(result.errorPos == -1);
return result.filteredHtml;
}

Result fromMatrixHtml(const QString& matrixHtml, QuaternionRoom* context,
Options options)
{
// Matrix HTML body should never be treated as Markdown
Q_ASSERT(!options.testFlag(ConvertMarkdown));
auto result = Processor::process(matrixHtml, MatrixToQt, context, options);
if (result.errorPos == -1) {
// Make sure to preserve whitespace sequences
result.filteredHtml = "<span style=\"white-space: pre-wrap\">"
% result.filteredHtml % "</span>";
}
return result;
}

Result fromLocalHtml(const QString& html,
QuaternionRoom* context, Options options)
{
return Processor::process(html, GenericToQt, context, options);
}

namespace {
class EntityResolver : public QXmlStreamEntityResolver {
public:
Expand Down Expand Up @@ -447,6 +415,10 @@ void Processor::runOn(const QString &html)
break;
}
}
if (options.testFlag(StripMxReply) && tagName == u"mx-reply") {
reader.skipCurrentElement();
continue;
}

const auto& attrs = reader.attributes();
if (ranges::any_of(attrs, [](const auto& a) {
Expand Down Expand Up @@ -765,5 +737,35 @@ void Processor::filterText(QString& text)

text.clear();
}
}

namespace HtmlFilter {

QString toMatrixHtml(const QString& qtMarkup, QuaternionRoom* context, Options options)
{
// Validation of HTML emitted by Qt doesn't make much sense
Q_ASSERT(!options.testFlag(Validate));
const auto& result = Processor::process(qtMarkup, QtToMatrix, context, options);
Q_ASSERT(result.errorPos == -1);
return result.filteredHtml;
}

Result fromMatrixHtml(const QString& matrixHtml, QuaternionRoom* context, Options options)
{
// Matrix HTML body should never be treated as Markdown
Q_ASSERT(!options.testFlag(ConvertMarkdown));
auto result = Processor::process(matrixHtml, MatrixToQt, context, options);
if (result.errorPos == -1) {
// Make sure to preserve whitespace sequences
result.filteredHtml =
"<span style=\"white-space: pre-wrap\">" % result.filteredHtml % "</span>";
}
return result;
}

Result fromLocalHtml(const QString& html, QuaternionRoom* context, Options options)
{
return Processor::process(html, GenericToQt, context, options);
}

} // namespace HtmlFilter
16 changes: 9 additions & 7 deletions client/htmlfilter.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,15 +10,17 @@ Q_NAMESPACE

enum Option : unsigned char {
Default = 0x0,
/// Treat `<body>` contents as Markdown (toMatrixHtml() only)
//! Treat `<body>` contents as Markdown (toMatrixHtml() only)
ConvertMarkdown = 0x1,
/// Treat `<body>` contents as a fragment in a bigger HTML payload
/// (suppresses markup processing inside HTML elements and `<mx-reply>`
/// conversion - toMatrixHtml() only)
//! Treat `<body>` contents as a fragment in a bigger HTML payload
//! (suppresses markup processing inside HTML elements and `<mx-reply>`
//! conversion - toMatrixHtml() only)
Fragment = 0x2,
/// Stop at tags not allowed in Matrix, instead of ignoring them
/// (from*Html() functions only)
Validate = 0x4
//! Stop at tags not allowed in Matrix, instead of ignoring them
//! (from*Html() functions only)
Validate = 0x4,
//! Remove <mx-reply> elements previously used for reply fallbacks
StripMxReply = 0x8
};
Q_ENUM_NS(Option)
Q_DECLARE_FLAGS(Options, Option)
Expand Down

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