fix(renderer): Drop strings with invalid UTF8

include/cairo/context.hpp

@@ -163,9 +163,14 @@ namespace cairo {
         std::iter_swap(fns.begin(), fns.begin() + t.font - 1);
       }
 
-      string utf8 = string(t.contents);
+      string utf8 = t.contents;
       string_util::unicode_charlist chars;
-      string_util::utf8_to_ucs4(utf8.c_str(), chars);
+      bool success = string_util::utf8_to_ucs4(utf8.c_str(), chars);
+
+      if (!success) {
+        m_log.warn("Dropping invalid UTF8 text '%s'", utf8);
+        return *this;
+      }
 
       while (!chars.empty()) {
         auto remaining = chars.size();

include/cairo/font.hpp

@@ -220,10 +220,6 @@ class font_fc : public font {
         m_scaled, x, y, utf8.c_str(), utf8.size(), &glyphs, &nglyphs, &clusters, &nclusters, &cf);
 
     if (status != CAIRO_STATUS_SUCCESS) {
-      logger::make().notice("ERROR %d", status);
-      for (char& c : utf8) {
-        logger::make().notice("0x%02x", c);
-      }
       throw application_error(sstream() << "cairo_scaled_font_text_to_glyphs() " << cairo_status_to_string(status));
     }
 

include/utils/string.hpp

@@ -24,7 +24,7 @@ class sstream {
     return m_stream.str();
   }
 
-   string to_string() const {
+  string to_string() const {
     return m_stream.str();
   }
 
@@ -88,7 +88,7 @@ string utf8_truncate(string&& value, size_t len);
 /**
  * @brief Create a UCS-4 codepoint from a utf-8 encoded string
  */
-bool utf8_to_ucs4(const char* src, unicode_charlist& result_list);
+[[nodiscard]] bool utf8_to_ucs4(const char* src, unicode_charlist& result_list);
 
 /**
  * @brief Convert a UCS-4 codepoint to a utf-8 encoded string

src/utils/string.cpp

@@ -270,7 +270,7 @@ static pair<int, uint32_t> utf8_get_len(uint8_t leading) {
 }
 
 /**
- * @brief Create a UCS-4 codepoint from a utf-8 encoded string
+ * @brief Create a list of UCS-4 codepoint from a utf-8 encoded string
  */
 bool utf8_to_ucs4(const char* src, unicode_charlist& result_list) {
   if (!src) {