cairo_show_text内存泄漏

Question

对于下面的代码

bool CustomCairoRenderer::renderString(const std::string &str,const Coordinates &renderFrom)
{
    if(cairo_surface_status(_surface)!= CAIRO_STATUS_SUCCESS||cairo_status(_cr)!=CAIRO_STATUS_SUCCESS)
    {
        return false;
    }
    cairo_move_to (_cr,renderFrom.x, renderFrom.y);
    cairo_show_text (_cr, str.c_str());
    return true;
}

我收到以下 valgrind 错误

==919== HEAP SUMMARY:
==919==     in use at exit: 578,997 bytes in 4,390 blocks
==919==   total heap usage: 20,456 allocs, 16,066 frees, 5,505,886 
          bytes allocated
==919== 
==919== 288 (256 direct, 32 indirect) bytes in 1 blocks are definitely lost in loss record 123 of 212
==919==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==919==    by 0x670B0B9: ??? (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x670B829: ??? (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x670CD4A: ??? (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x671219B: ??? (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x7FB0A9B: ??? (in /lib/x86_64-linux- gnu/libexpat.so.1.6.0)
==919==    by 0x7FB13AB: ??? (in /lib/x86_64-linux- gnu/libexpat.so.1.6.0)
==919==    by 0x7FB2CCD: ??? (in /lib/x86_64-linux- gnu/libexpat.so.1.6.0)
==919==    by 0x7FB3424: ??? (in /lib/x86_64-linux- gnu/libexpat.so.1.6.0)
==919==    by 0x7FB572A: XML_ParseBuffer (in /lib/x86_64-linux- gnu/libexpat.so.1.6.0)
==919==    by 0x671152A: FcConfigParseAndLoad (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==919==    by 0x6711836: FcConfigParseAndLoad (in /usr/lib/x86_64- linux-gnu/libfontconfig.so.1.9.0)
==919== 
==919== 353 (256 direct, 97 indirect) bytes in 1 blocks are definitely lost in loss record 138 of 212
==919==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==919==    by 0x670B0B9: ??? (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x670B829: ??? (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x670C47A: FcPatternDuplicate (in /usr/lib/x86_64-linux- gnu/libfontconfig.so.1.9.0)
==919==    by 0x514BFB2: ??? (in /usr/lib/x86_64-linux- gnu/libcairo.so.2.11400.6)
==919==    by 0x514C19D: ??? (in /usr/lib/x86_64-linux- gnu/libcairo.so.2.11400.6)
==919==    by 0x5110107: cairo_toy_font_face_create (in /usr/lib/x86_64-linux-gnu/libcairo.so.2.11400.6)
==919==    by 0x50BFD6F: ??? (in /usr/lib/x86_64-linux-        gnu/libcairo.so.2.11400.6)
==919==    by 0x50C2C60: ??? (in /usr/lib/x86_64-linux- gnu/libcairo.so.2.11400.6)
==919==    by 0x50BB0FF: ??? (in /usr/lib/x86_64-linux- gnu/libcairo.so.2.11400.6)
==919==    by 0x50B5242: cairo_show_text (in /usr/lib/x86_64-linux- gnu/libcairo.so.2.11400.6)
==919==    by 0x44A978: CustomCairoRenderer::renderString(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, Coordinates const&, ) (customcairorenderer.cpp:166)
==919== 
==919== LEAK SUMMARY:
==919==    definitely lost: 512 bytes in 2 blocks
==919==    indirectly lost: 129 bytes in 5 blocks
==919==      possibly lost: 0 bytes in 0 blocks
==919==    still reachable: 578,356 bytes in 4,383 blocks
==919==         suppressed: 0 bytes in 0 blocks
==919== Reachable blocks (those to which a pointer was found) are not shown.

这个函数专门只渲染给定的字符串。 cairo/surface 创建和销毁是在 class 构造函数和析构函数中完成的。谁能发现我在这段代码中做错了什么？我在 Ubuntu 16.04LTS

上使用 cairo 版本 1.14.6

更新： 似乎调用 cairo_debug_reset_static_data (); 会抑制一些提到的错误 here。但现在我面临另一个来自 fontconfig 的 valgrind 错误，不知道如何修复它。

==4546== HEAP SUMMARY:
==4546==     in use at exit: 489,708 bytes in 4,130 blocks
==4546==   total heap usage: 24,149 allocs, 20,019 frees, 5,806,541 bytes allocated
==4546== 
==4546== 288 (256 direct, 32 indirect) bytes in 1 blocks are definitely lost in loss record 88 of 132
==4546==    at 0x4C2DB8F: malloc (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==4546==    by 0x670B0B9: ??? (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==4546==    by 0x670B829: ??? (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==4546==    by 0x670CD4A: ??? (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==4546==    by 0x671219B: ??? (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==4546==    by 0x7FB0A9B: ??? (in /lib/x86_64-linux-gnu/libexpat.so.1.6.0)
==4546==    by 0x7FB13AB: ??? (in /lib/x86_64-linux-gnu/libexpat.so.1.6.0)
==4546==    by 0x7FB2CCD: ??? (in /lib/x86_64-linux-gnu/libexpat.so.1.6.0)
==4546==    by 0x7FB3424: ??? (in /lib/x86_64-linux-gnu/libexpat.so.1.6.0)
==4546==    by 0x7FB572A: XML_ParseBuffer (in /lib/x86_64-linux-gnu/libexpat.so.1.6.0)
==4546==    by 0x671152A: FcConfigParseAndLoad (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==4546==    by 0x6711836: FcConfigParseAndLoad (in /usr/lib/x86_64-linux-gnu/libfontconfig.so.1.9.0)
==4546== 
==4546== LEAK SUMMARY:
==4546==    definitely lost: 256 bytes in 1 blocks
==4546==    indirectly lost: 32 bytes in 1 blocks
==4546==      possibly lost: 0 bytes in 0 blocks
==4546==    still reachable: 489,420 bytes in 4,128 blocks
==4546==         suppressed: 0 bytes in 0 blocks
==4546== Reachable blocks (those to which a pointer was found) are not shown.

Answer 1

Seems like calling cairo_debug_reset_static_data (); will suppress some errors as mentioned here. But now I'm facing another valgrind error from fontconfig , no idea how to fix it.

调用 FcFini()（在 cairo_debug_reset_static_data() 之后）。

cairo_show_text内存泄漏

cairo_show_text memory leak

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