Use memory pool for PolyTextOut items in GDI Renderer

.github/actions/spell-check/dictionary/apis.txt

@@ -56,6 +56,7 @@ otms
 OUTLINETEXTMETRICW
 overridable
 PAGESCROLL
+pmr
 RETURNCMD
 rfind
 roundf

src/inc/LibraryIncludes.h

@@ -23,6 +23,7 @@
 #include <deque>
 #include <list>
 #include <memory>
+#include <memory_resource>
 #include <map>
 #include <mutex>
 #include <shared_mutex>

src/renderer/gdi/gdirenderer.hpp

@@ -125,6 +125,13 @@ namespace Microsoft::Console::Render
         COLORREF _lastBg;
         bool _lastFontItalic;
 
+        // Memory pooling to save alloc/free work to the OS for things
+        // frequently created and dropped.
+        // It's important the pool is first so it can be given to the others on construction.
+        std::pmr::unsynchronized_pool_resource _pool;
+        std::pmr::vector<std::pmr::wstring> _polyStrings;
+        std::pmr::vector<std::pmr::basic_string<int>> _polyWidths;
+
         [[nodiscard]] HRESULT _InvalidCombine(const RECT* const prc) noexcept;
         [[nodiscard]] HRESULT _InvalidOffset(const POINT* const ppt) noexcept;
         [[nodiscard]] HRESULT _InvalidRestrict() noexcept;

src/renderer/gdi/paint.cpp

@@ -308,13 +308,11 @@ using namespace Microsoft::Console::Render;
 
         const auto pPolyTextLine = &_pPolyText[_cPolyText];
 
-        auto pwsPoly = std::make_unique<wchar_t[]>(cchLine);
-        RETURN_IF_NULL_ALLOC(pwsPoly);
+        auto& polyString = _polyStrings.emplace_back(cchLine, UNICODE_NULL);
 
         COORD const coordFontSize = _GetFontSize();
 
-        auto rgdxPoly = std::make_unique<int[]>(cchLine);
-        RETURN_IF_NULL_ALLOC(rgdxPoly);
+        auto& polyWidth = _polyWidths.emplace_back(cchLine, 0);
 
         // Sum up the total widths the entire line/run is expected to take while
         // copying the pixel widths into a structure to direct GDI how many pixels to use per character.
@@ -327,9 +325,9 @@ using namespace Microsoft::Console::Render;
 
             // Our GDI renderer hasn't and isn't going to handle things above U+FFFF or sequences.
             // So replace anything complicated with a replacement character for drawing purposes.
-            pwsPoly[i] = cluster.GetTextAsSingle();
-            rgdxPoly[i] = gsl::narrow<int>(cluster.GetColumns()) * coordFontSize.X;
-            cchCharWidths += rgdxPoly[i];
+            polyString[i] = cluster.GetTextAsSingle();
+            polyWidth[i] = gsl::narrow<int>(cluster.GetColumns()) * coordFontSize.X;
+            cchCharWidths += polyWidth[i];
         }
 
         // Detect and convert for raster font...
@@ -338,15 +336,15 @@ using namespace Microsoft::Console::Render;
             // dispatch conversion into our codepage
 
             // Find out the bytes required
-            int const cbRequired = WideCharToMultiByte(_fontCodepage, 0, pwsPoly.get(), (int)cchLine, nullptr, 0, nullptr, nullptr);
+            int const cbRequired = WideCharToMultiByte(_fontCodepage, 0, polyString.data(), (int)cchLine, nullptr, 0, nullptr, nullptr);
 
             if (cbRequired != 0)
             {
                 // Allocate buffer for MultiByte
                 auto psConverted = std::make_unique<char[]>(cbRequired);
 
                 // Attempt conversion to current codepage
-                int const cbConverted = WideCharToMultiByte(_fontCodepage, 0, pwsPoly.get(), (int)cchLine, psConverted.get(), cbRequired, nullptr, nullptr);
+                int const cbConverted = WideCharToMultiByte(_fontCodepage, 0, polyString.data(), (int)cchLine, psConverted.get(), cbRequired, nullptr, nullptr);
 
                 // If successful...
                 if (cbConverted != 0)
@@ -356,22 +354,22 @@ using namespace Microsoft::Console::Render;
 
                     if (cchRequired != 0)
                     {
-                        auto pwsConvert = std::make_unique<wchar_t[]>(cchRequired);
+                        std::pmr::wstring polyConvert(cchRequired, UNICODE_NULL, &_pool);
 
                         // Then do the actual conversion.
-                        int const cchConverted = MultiByteToWideChar(CP_ACP, 0, psConverted.get(), cbRequired, pwsConvert.get(), cchRequired);
+                        int const cchConverted = MultiByteToWideChar(CP_ACP, 0, psConverted.get(), cbRequired, polyConvert.data(), cchRequired);
 
                         if (cchConverted != 0)
                         {
                             // If all successful, use this instead.
-                            pwsPoly.swap(pwsConvert);
+                            polyString.swap(polyConvert);
                         }
                     }
                 }
             }
         }
 
-        pPolyTextLine->lpstr = pwsPoly.release();
+        pPolyTextLine->lpstr = polyString.data();
         pPolyTextLine->n = gsl::narrow<UINT>(clusters.size());
         pPolyTextLine->x = ptDraw.x;
         pPolyTextLine->y = ptDraw.y;
@@ -380,7 +378,7 @@ using namespace Microsoft::Console::Render;
         pPolyTextLine->rcl.top = pPolyTextLine->y;
         pPolyTextLine->rcl.right = pPolyTextLine->rcl.left + ((SHORT)cchCharWidths * coordFontSize.X);
         pPolyTextLine->rcl.bottom = pPolyTextLine->rcl.top + coordFontSize.Y;
-        pPolyTextLine->pdx = rgdxPoly.release();
+        pPolyTextLine->pdx = polyWidth.data();
 
         if (trimLeft)
         {
@@ -417,20 +415,10 @@ using namespace Microsoft::Console::Render;
             hr = E_FAIL;
         }
 
-        for (size_t iPoly = 0; iPoly < _cPolyText; iPoly++)
-        {
-            if (nullptr != _pPolyText[iPoly].lpstr)
-            {
-                delete[] _pPolyText[iPoly].lpstr;
-                _pPolyText[iPoly].lpstr = nullptr;
-            }
+        _polyStrings.clear();
+        _polyWidths.clear();
 
-            if (nullptr != _pPolyText[iPoly].pdx)
-            {
-                delete[] _pPolyText[iPoly].pdx;
-                _pPolyText[iPoly].pdx = nullptr;
-            }
-        }
+        ZeroMemory(_pPolyText, sizeof(_pPolyText));
 
         _cPolyText = 0;
     }

src/renderer/gdi/state.cpp

@@ -32,7 +32,10 @@ GdiEngine::GdiEngine() :
     _lastFontItalic(false),
     _fPaintStarted(false),
     _hfont(nullptr),
-    _hfontItalic(nullptr)
+    _hfontItalic(nullptr),
+    _pool{}, // It's important the pool is first so it can be given to the others on construction.
+    _polyStrings{ &_pool },
+    _polyWidths{ &_pool }
 {
     ZeroMemory(_pPolyText, sizeof(POLYTEXTW) * s_cPolyTextCache);
     _rcInvalid = { 0 };