Use native candidate actions and harden frontend resource loading

tests/testm3uiimageloader.cpp

@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+#include <cstdint>
+#include <string>
+#include <vector>
+#include "fcitx-utils/log.h"
+#include "../src/imageloader.h"
+
+using namespace fcitx::m3ui;
+
+int main() {
+    FCITX_ASSERT(!loadRasterImage({}));
+    FCITX_ASSERT(!loadSvgImage({}));
+    FCITX_ASSERT(!loadRasterImage({'b', 'a', 'd'}));
+    FCITX_ASSERT(!loadSvgImage({'b', 'a', 'd'}));
+
+    // Valid PNG bytes exercise the real incremental decoder, regardless of
+    // extension. The reference must remain valid after loader destruction.
+    LoadedSurface surface(cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 16, 16));
+    std::vector<uint8_t> png;
+    FCITX_ASSERT(cairo_surface_write_to_png_stream(
+        surface.get(),
+        +[](void *data, const unsigned char *bytes, unsigned int length) {
+            auto &out = *static_cast<std::vector<uint8_t> *>(data);
+            out.insert(out.end(), bytes, bytes + length);
+            return CAIRO_STATUS_SUCCESS;
+        },
+        &png) == CAIRO_STATUS_SUCCESS);
+    auto image = loadRasterImage(png);
+    FCITX_ASSERT(image);
+    FCITX_ASSERT(gdk_pixbuf_get_width(image.get()) == 16);
+    FCITX_ASSERT(gdk_pixbuf_get_height(image.get()) == 16);
+    png[16] = 255; // Huge IHDR, rejected before entering libpng.
+    FCITX_ASSERT(!loadRasterImage(png));
+    png.resize(23);
+    FCITX_ASSERT(!loadRasterImage(png));
+
+    // A real non-PNG image exercises size-prepared rather than PNG preflight.
+    gchar *bmpData = nullptr;
+    gsize bmpSize = 0;
+    FCITX_ASSERT(gdk_pixbuf_save_to_buffer(image.get(), &bmpData, &bmpSize,
+                                         "bmp", nullptr, nullptr));
+    std::vector<uint8_t> bmp(bmpData, bmpData + bmpSize);
+    g_free(bmpData);
+    FCITX_ASSERT(loadRasterImage(bmp));
+    // BMP BITMAPINFOHEADER width is little-endian at byte 18.
+    FCITX_ASSERT(bmp.size() > 26 && bmp[14] >= 40);
+    bmp[18] = 1;
+    bmp[19] = 32; // 8193 pixels wide
+    bmp[20] = bmp[21] = 0;
+    FCITX_ASSERT(!loadRasterImage(bmp));
+
+    auto svg = [](const std::string &text) {
+        return loadSvgImage(std::vector<uint8_t>(text.begin(), text.end()));
+    };
+    auto rendered = svg("<svg xmlns='http://www.w3.org/2000/svg' width='16' "
+                        "height='16'><rect width='16' height='16' "
+                        "fill='red'/></svg>");
+    FCITX_ASSERT(rendered);
+    FCITX_ASSERT(cairo_surface_get_type(rendered.get()) == CAIRO_SURFACE_TYPE_IMAGE);
+    FCITX_ASSERT(cairo_image_surface_get_width(rendered.get()) == 16);
+    FCITX_ASSERT(cairo_image_surface_get_height(rendered.get()) == 16);
+    cairo_surface_flush(rendered.get());
+    const auto *pixel = reinterpret_cast<const uint32_t *>(
+        cairo_image_surface_get_data(rendered.get()));
+    FCITX_ASSERT(pixel[0] == 0xffff0000); // Native-endian Cairo ARGB32.
+    FCITX_ASSERT(!svg("<svg xmlns='http://www.w3.org/2000/svg' "
+                      "width='1e30' height='16'/>"));
+    FCITX_ASSERT(!svg("<svg xmlns='http://www.w3.org/2000/svg' "
+                      "width='8192' height='8192'/>"));
+    FCITX_ASSERT(!svg("<svg xmlns='http://www.w3.org/2000/svg' "
+                      "width='0' height='16'/>"));
+    FCITX_ASSERT(!svg("<svg xmlns='http://www.w3.org/2000/svg'"));
+
+    std::vector<uint8_t> oversized(16 * 1024 * 1024 + 1);
+    FCITX_ASSERT(!loadRasterImage(oversized));
+    FCITX_ASSERT(!loadSvgImage(oversized));
+}