From b0a642df750c19c62470d13702eeade4b0d1966a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Lukas=20Br=C3=BCbach?= Date: Tue, 20 Oct 2026 11:24:03 +0200 Subject: [PATCH] [Icons] Add SVG currentColor sentinel resolver Qt's SVG renderer has no CSS cascade, so a `currentColor` fill has to be substituted before the bytes reach QSvgRenderer. - Match and replace on bytes: both the sentinel and the replacement are ASCII, so the document never goes through a UTF-16 round trip, and files that are not valid UTF-8 survive unchanged. - Document that the match is a plain case-insensitive substring, so an identifier that merely starts with the sentinel gets rewritten too. --- libcockatrice_utility/CMakeLists.txt | 2 + .../libcockatrice/utility/svg_recolor.cpp | 44 +++++++++++++ .../libcockatrice/utility/svg_recolor.h | 31 +++++++++ tests/CMakeLists.txt | 1 + tests/svg_recolor_test.cpp | 66 +++++++++++++++++++ 5 files changed, 144 insertions(+) create mode 100644 libcockatrice_utility/libcockatrice/utility/svg_recolor.cpp create mode 100644 libcockatrice_utility/libcockatrice/utility/svg_recolor.h create mode 100644 tests/svg_recolor_test.cpp diff --git a/libcockatrice_utility/CMakeLists.txt b/libcockatrice_utility/CMakeLists.txt index 8d2cb5b92..98ad40e69 100644 --- a/libcockatrice_utility/CMakeLists.txt +++ b/libcockatrice_utility/CMakeLists.txt @@ -8,6 +8,7 @@ set(UTILITY_SOURCES libcockatrice/utility/passwordhasher.cpp libcockatrice/utility/report_categories.cpp libcockatrice/utility/server_rate_limiter.cpp + libcockatrice/utility/svg_recolor.cpp libcockatrice/utility/translation_loader.cpp libcockatrice/utility/user_data_backup.cpp libcockatrice/utility/warning_categories.cpp @@ -34,6 +35,7 @@ set(UTILITY_HEADERS libcockatrice/utility/zone_names.h libcockatrice/utility/days_years_between.h libcockatrice/utility/server_rate_limiter.h + libcockatrice/utility/svg_recolor.h libcockatrice/utility/translation_loader.h libcockatrice/utility/user_data_backup.h libcockatrice/utility/warning_categories.h diff --git a/libcockatrice_utility/libcockatrice/utility/svg_recolor.cpp b/libcockatrice_utility/libcockatrice/utility/svg_recolor.cpp new file mode 100644 index 000000000..041e289fe --- /dev/null +++ b/libcockatrice_utility/libcockatrice/utility/svg_recolor.cpp @@ -0,0 +1,44 @@ +#include "svg_recolor.h" + +#include + +namespace +{ +constexpr QByteArrayView SENTINEL = "currentColor"; + +/// Case-insensitive byte search for the sentinel, starting at @p from. +/// QByteArray::indexOf() only matches case-sensitively for QByteArrayView, and +/// its char overload cannot match a word. +qsizetype findSentinel(const QByteArray &bytes, qsizetype from) +{ + // QByteArrayView::sliced() is a view, so the scan does not allocate a copy + // at every byte position (QByteArray::sliced() would). + const QByteArrayView view(bytes); + for (qsizetype i = from; i + SENTINEL.size() <= view.size(); ++i) { + if (view.sliced(i, SENTINEL.size()).compare(SENTINEL, Qt::CaseInsensitive) == 0) { + return i; + } + } + return -1; +} +} // namespace + +QByteArray resolveSvgColorSentinel(const QByteArray &svg, const QByteArray &color) +{ + // The sentinel and the replacement are both ASCII, so stay in bytes: a + // QString round trip would decode the whole document (and mangle bytes that + // are not valid UTF-8) even on the no-op path. + qsizetype pos = findSentinel(svg, 0); + if (pos < 0) { + return svg; + } + + QByteArray resolved = svg; + while (pos >= 0) { + resolved.replace(pos, SENTINEL.size(), color); + // Skip past the inserted color: a caller's color never contains the + // sentinel, and this keeps the scan linear. + pos = findSentinel(resolved, pos + color.size()); + } + return resolved; +} diff --git a/libcockatrice_utility/libcockatrice/utility/svg_recolor.h b/libcockatrice_utility/libcockatrice/utility/svg_recolor.h new file mode 100644 index 000000000..56d609b87 --- /dev/null +++ b/libcockatrice_utility/libcockatrice/utility/svg_recolor.h @@ -0,0 +1,31 @@ +/** + * @file svg_recolor.h + * @ingroup Core + */ + +#ifndef SVG_RECOLOR_H +#define SVG_RECOLOR_H + +#include + +/** + * @brief Resolves the `currentColor` sentinel in authored SVG data. + * + * Qt's SVG renderer has no CSS cascade or ambient color context, so the + * sentinel is not resolved by Qt. Callers pass the concrete color they want + * (for example a QPalette role serialized to #RRGGBB) and receive SVG bytes + * that are safe to hand to QSvgRenderer. + * + * Matching is a plain, case-insensitive substring search, not a CSS parse: an + * identifier that merely starts with the sentinel (for example + * `id="currentColorStop"`) is rewritten too. That is acceptable for the assets + * this project authors, and keeps the resolver dependency-free. + * + * @param svg SVG source bytes, expected to be UTF-8. Invalid UTF-8 is preserved + * byte-for-byte, since the resolver never decodes the document. + * @param color Concrete SVG color (for example "#ff00ff"), as ASCII bytes. + * @return The recolored SVG source; the input is left untouched. + */ +QByteArray resolveSvgColorSentinel(const QByteArray &svg, const QByteArray &color); + +#endif // SVG_RECOLOR_H diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt index 0bb9654a1..5dff3a761 100644 --- a/tests/CMakeLists.txt +++ b/tests/CMakeLists.txt @@ -177,6 +177,7 @@ cockatrice_add_test(NAME test_age_formatting SOURCES test_age_formatting.cpp LIB cockatrice_add_test(NAME user_data_backup_test SOURCES user_data_backup_test.cpp LIBS libcockatrice_utility) cockatrice_add_test(NAME password_hash_test SOURCES password_hash_test.cpp LIBS libcockatrice_utility) cockatrice_add_test(NAME report_categories_test SOURCES report_categories_test.cpp LIBS libcockatrice_utility) +cockatrice_add_test(NAME svg_recolor_test SOURCES svg_recolor_test.cpp LIBS libcockatrice_utility) cockatrice_add_test(NAME warning_categories_test SOURCES warning_categories_test.cpp LIBS libcockatrice_utility) # The installer's holder probe is Windows-only, but the wording it produces and the # question which programs are the payload's own are plain C++ and are what a stuck user diff --git a/tests/svg_recolor_test.cpp b/tests/svg_recolor_test.cpp new file mode 100644 index 000000000..abe1e8d1a --- /dev/null +++ b/tests/svg_recolor_test.cpp @@ -0,0 +1,66 @@ +#include "libcockatrice/utility/svg_recolor.h" + +#include +#include + +namespace +{ + +TEST(SvgRecolor, ReplacesEverySentinel) +{ + const QByteArray svg = R"()"; + const QByteArray result = resolveSvgColorSentinel(svg, "#ff8800"); + + EXPECT_EQ(result.count("#ff8800"), 2); + EXPECT_FALSE(result.contains("currentColor")); +} + +TEST(SvgRecolor, ReplacesSentinelRegardlessOfCase) +{ + const QByteArray svg = R"()"; + + EXPECT_EQ(resolveSvgColorSentinel(svg, "#ff8800").count("#ff8800"), 2); +} + +TEST(SvgRecolor, LeavesTheRestOfTheDocumentIntact) +{ + const QByteArray svg = + R"()"; + const QByteArray result = resolveSvgColorSentinel(svg, "#123456"); + + EXPECT_TRUE(result.contains(R"(viewBox="0 0 24 24")")); + EXPECT_TRUE(result.contains(R"(d="M0 0h24v24")")); + EXPECT_TRUE(result.contains("an ordinary comment")); +} + +TEST(SvgRecolor, DoesNotModifyTheInput) +{ + const QByteArray svg = R"()"; + const QByteArray original = svg; + + resolveSvgColorSentinel(svg, "#000000"); + + EXPECT_EQ(svg, original); +} + +TEST(SvgRecolor, PreservesBytesThatAreNotValidUtf8) +{ + QByteArray svg = ""; + svg.append("\xff\xfe"); + svg.append(R"()"); + + const QByteArray result = resolveSvgColorSentinel(svg, "#ff8800"); + + EXPECT_TRUE(result.contains("\xff\xfe")); + EXPECT_FALSE(result.contains("currentColor")); + EXPECT_EQ(result.count("#ff8800"), 1); +} + +TEST(SvgRecolor, NoSentinelIsANoOp) +{ + const QByteArray svg = R"()"; + + EXPECT_EQ(resolveSvgColorSentinel(svg, "#ffffff"), svg); +} + +} // namespace