[SVGThumbnail]Optimize CPU usage (#28286)

* [SVG Thumbnail] Optimize CPU usage

* add missing zero

.github/actions/spell-check/expect.txt

@@ -2223,7 +2223,6 @@ Wubi
 WVC
 Wwan
 Wwanpp
-XAttribute
 XAxis
 xbf
 Xbox

src/modules/previewpane/SvgThumbnailProvider/SvgThumbnailProvider.cs

@@ -5,6 +5,7 @@ using System.Drawing.Drawing2D;
 using System.Globalization;
 using System.Reflection;
 using System.Runtime.CompilerServices;
+using System.Threading;
 using Common.Utilities;
 using Microsoft.Web.WebView2.Core;
 using Microsoft.Web.WebView2.WinForms;
@@ -35,6 +36,13 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
         /// </summary>
         public Stream Stream { get; private set; }
 
+        /// <summary>
+        /// Gets or sets signalled when the main thread can use preprocessed svg contents.
+        /// </summary>
+        public ManualResetEventSlim SvgContentsReady { get; set; } = new ManualResetEventSlim(false);
+
+        public string SvgContents { get; set; } = string.Empty;
+
         /// <summary>
         ///  The maximum dimension (width or height) thumbnail we will generate.
         /// </summary>
@@ -87,20 +95,19 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
         /// Render SVG using WebView2 control, capture the WebView2
         /// preview and create Bitmap out of it.
         /// </summary>
-        /// <param name="content">The content to render.</param>
         /// <param name="cx">The maximum thumbnail size, in pixels.</param>
-        public Bitmap GetThumbnail(string content, uint cx)
+        public Bitmap GetThumbnailImpl(uint cx)
         {
             CleanupWebView2UserDataFolder();
 
-            if (cx == 0 || cx > MaxThumbnailSize || string.IsNullOrEmpty(content) || !content.Contains("svg"))
+            if (cx == 0 || cx > MaxThumbnailSize)
             {
                 return null;
             }
 
             Bitmap thumbnail = null;
-            bool thumbnailDone = false;
-            string wrappedContent = WrapSVGInHTML(content);
+
+            var thumbnailDone = new ManualResetEventSlim(false);
 
             _browser = new WebView2();
             _browser.Dock = DockStyle.Fill;
@@ -132,7 +139,7 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
                     thumbnail = ResizeImage(thumbnail, scaleWidth, scaleHeight);
                 }
 
-                thumbnailDone = true;
+                thumbnailDone.Set();
             };
 
             var webView2Options = new CoreWebView2EnvironmentOptions("--block-new-web-contents");
@@ -140,6 +147,7 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
                webView2EnvironmentAwaiter = CoreWebView2Environment
                    .CreateAsync(userDataFolder: _webView2UserDataFolder, options: webView2Options)
                    .ConfigureAwait(true).GetAwaiter();
+
             webView2EnvironmentAwaiter.OnCompleted(async () =>
             {
                 try
@@ -170,16 +178,23 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
                     // WebView2.NavigateToString() limitation
                     // See https://learn.microsoft.com/dotnet/api/microsoft.web.webview2.core.corewebview2.navigatetostring?view=webview2-dotnet-1.0.864.35#remarks
                     // While testing the limit, it turned out it is ~1.5MB, so to be on a safe side we go for 1.5m bytes
-                    if (wrappedContent.Length > 1_500_000)
+                    SvgContentsReady.Wait();
+                    if (string.IsNullOrEmpty(SvgContents) || !SvgContents.Contains("svg"))
+                    {
+                        thumbnailDone.Set();
+                        return;
+                    }
+
+                    if (SvgContents.Length > 1_500_000)
                     {
                         string filename = _webView2UserDataFolder + "\\" + Guid.NewGuid().ToString() + ".html";
-                        File.WriteAllText(filename, wrappedContent);
+                        File.WriteAllText(filename, SvgContents);
                         _localFileURI = new Uri(filename);
                         _browser.Source = _localFileURI;
                     }
                     else
                     {
-                        _browser.NavigateToString(wrappedContent);
+                        _browser.NavigateToString(SvgContents);
                     }
                 }
                 catch (Exception)
@@ -187,7 +202,7 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
                 }
             });
 
-            while (thumbnailDone == false)
+            while (!thumbnailDone.Wait(75))
             {
                 Application.DoEvents();
             }
@@ -276,31 +291,41 @@ namespace Microsoft.PowerToys.ThumbnailHandler.Svg
                 return null;
             }
 
-            string svgData = null;
-            using (var reader = new StreamReader(this.Stream))
+            if (Stream != null)
             {
-                svgData = reader.ReadToEnd();
-                try
+                new Thread(() =>
                 {
-                    // Fixes #17527 - Inkscape v1.1 swapped order of default and svg namespaces in svg file (default first, svg after).
-                    // That resulted in parser being unable to parse it correctly and instead of svg, text was previewed.
-                    // MS Edge and Firefox also couldn't preview svg files with mentioned order of namespaces definitions.
-                    svgData = SvgPreviewHandlerHelper.SwapNamespaces(svgData);
-                    svgData = SvgPreviewHandlerHelper.AddStyleSVG(svgData);
-                }
-                catch (Exception)
-                {
-                }
+                    string svgData = null;
+                    using (var reader = new StreamReader(Stream))
+                    {
+                        svgData = reader.ReadToEnd();
+                        try
+                        {
+                            // Fixes #17527 - Inkscape v1.1 swapped order of default and svg namespaces in svg file (default first, svg after).
+                            // That resulted in parser being unable to parse it correctly and instead of svg, text was previewed.
+                            // MS Edge and Firefox also couldn't preview svg files with mentioned order of namespaces definitions.
+                            svgData = SvgPreviewHandlerHelper.SwapNamespaces(svgData);
+                            svgData = SvgPreviewHandlerHelper.AddStyleSVG(svgData);
+                            SvgContents = WrapSVGInHTML(svgData);
+                            SvgContentsReady.Set();
+                        }
+                        catch (Exception)
+                        {
+                            SvgContentsReady.Set();
+                        }
+                    }
+                }).Start();
+            }
+            else
+            {
+                SvgContentsReady.Set();
             }
 
-            if (svgData != null)
+            using (Bitmap thumbnail = GetThumbnailImpl(cx))
             {
-                using (Bitmap thumbnail = GetThumbnail(svgData, cx))
+                if (thumbnail != null && thumbnail.Size.Width > 0 && thumbnail.Size.Height > 0)
                 {
-                    if (thumbnail != null && thumbnail.Size.Width > 0 && thumbnail.Size.Height > 0)
-                    {
-                        return (Bitmap)thumbnail.Clone();
-                    }
+                    return (Bitmap)thumbnail.Clone();
                 }
             }
 

src/modules/previewpane/UnitTests-SvgThumbnailProvider/SvgThumbnailProviderTests.cs

@@ -28,7 +28,9 @@ namespace SvgThumbnailProviderUnitTests
             svgBuilder.AppendLine("</svg>");
 
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(svgBuilder.ToString(), 256);
+            svgThumbnailProvider.SvgContents = svgBuilder.ToString();
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
 
             Assert.IsNotNull(thumbnail);
             Assert.IsTrue(thumbnail.Width > 0);
@@ -46,7 +48,73 @@ namespace SvgThumbnailProviderUnitTests
             svgBuilder.AppendLine("</svg>");
 
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(svgBuilder.ToString(), 256);
+            svgThumbnailProvider.SvgContents = svgBuilder.ToString();
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
+            Assert.IsTrue(thumbnail != null);
+        }
+
+        [TestMethod]
+        public void CheckThatWidthAndHeightAreParsedCorrectly1()
+        {
+            SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
+            svgThumbnailProvider.SvgContents = @"
+<svg
+   xmlns:dc=""http://purl.org/dc/elements/1.1/""
+    xmlns:rdf=""http://www.w3.org/1999/02/22-rdf-syntax-ns#""
+   xmlns:svg=""http://www.w3.org/2000/svg""
+   xmlns=""http://www.w3.org/2000/svg""
+   xmlns:xlink=""http://www.w3.org/1999/xlink""
+   id=""svg8""
+   version=""1.1""
+   viewBox=""0 0 380.99999 304.79999"" width=""1px"" height=""20pt"" >
+";
+
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
+            Assert.IsTrue(thumbnail != null);
+        }
+
+        [TestMethod]
+        public void CheckThatWidthAndHeightAreParsedCorrectly2()
+        {
+            SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
+            svgThumbnailProvider.SvgContents = @"
+
+<svg
+   xmlns:dc=""http://purl.org/dc/elements/1.1/""
+    xmlns:rdf=""http://www.w3.org/1999/02/22-rdf-syntax-ns#""
+   xmlns:svg=""http://www.w3.org/2000/svg""
+   xmlns=""http://www.w3.org/2000/svg""
+   xmlns:xlink=""http://www.w3.org/1999/xlink""
+   id=""svg8""
+   version=""1.1""
+   height=""1152"" width=""2000vh"" >
+";
+
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
+            Assert.IsTrue(thumbnail != null);
+        }
+
+        [TestMethod]
+        public void CheckThatWidthAndHeightAreParsedCorrectly3()
+        {
+            SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
+            svgThumbnailProvider.SvgContents = @"
+
+<svg
+   xmlns:dc=""http://purl.org/dc/elements/1.1/""
+    xmlns:rdf=""http://www.w3.org/1999/02/22-rdf-syntax-ns#""
+   xmlns:svg=""http://www.w3.org/2000/svg""
+   xmlns=""http://www.w3.org/2000/svg""
+   xmlns:xlink=""http://www.w3.org/1999/xlink""
+   id=""svg8""
+   version=""1.1""
+   viewBox=""0 0 380.99999 304.79999"" width=""2000"" >
+";
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
             Assert.IsTrue(thumbnail != null);
         }
 
@@ -57,7 +125,9 @@ namespace SvgThumbnailProviderUnitTests
             svgBuilder.AppendLine("<p>foo</p>");
 
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(svgBuilder.ToString(), 256);
+            svgThumbnailProvider.SvgContents = svgBuilder.ToString();
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
             Assert.IsTrue(thumbnail == null);
         }
 
@@ -65,7 +135,9 @@ namespace SvgThumbnailProviderUnitTests
         public void CheckNoSvgEmptyStringShouldReturnNullBitmap()
         {
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(string.Empty, 256);
+            svgThumbnailProvider.SvgContents = string.Empty;
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
             Assert.IsTrue(thumbnail == null);
         }
 
@@ -73,7 +145,10 @@ namespace SvgThumbnailProviderUnitTests
         public void CheckNoSvgNullStringShouldReturnNullBitmap()
         {
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(null, 256);
+            svgThumbnailProvider.SvgContents = string.Empty;
+            svgThumbnailProvider.SvgContentsReady.Set();
+
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
             Assert.IsTrue(thumbnail == null);
         }
 
@@ -82,7 +157,9 @@ namespace SvgThumbnailProviderUnitTests
         {
             string content = "<svg></svg>";
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(content, 0);
+            svgThumbnailProvider.SvgContents = content;
+            svgThumbnailProvider.SvgContentsReady.Set();
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(0);
             Assert.IsTrue(thumbnail == null);
         }
 
@@ -104,7 +181,10 @@ namespace SvgThumbnailProviderUnitTests
             svgBuilder.AppendLine("</html>");
 
             SvgThumbnailProvider svgThumbnailProvider = new SvgThumbnailProvider(null);
-            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(svgBuilder.ToString(), 256);
+            svgThumbnailProvider.SvgContents = svgBuilder.ToString();
+            svgThumbnailProvider.SvgContentsReady.Set();
+
+            Bitmap thumbnail = svgThumbnailProvider.GetThumbnail(256);
             Assert.IsTrue(thumbnail != null);
         }
 

src/modules/previewpane/common/Utilities/SvgPreviewHandlerHelper.cs

@@ -15,6 +15,11 @@ namespace Common.Utilities
     /// </summary>
     public static class SvgPreviewHandlerHelper
     {
+        private const string WidthAttribute = "width=\"";
+        private const string HeightAttribute = "height=\"";
+        private const string StyleAttribute = "style=\"";
+        private const string ViewboxAttribute = "viewBox=\"";
+
         /// <summary>
         /// Dictionary of elements in lower case that are blocked from Svg for preview pane.
         /// Reference for list of Svg Elements: https://developer.mozilla.org/docs/Web/SVG/Element.
@@ -65,6 +70,83 @@ namespace Common.Utilities
             return foundBlockedElement;
         }
 
+        private static string GetAttributeValue(int attributeNameLength, string data, int startIndex)
+        {
+            if (startIndex == -1)
+            {
+                return string.Empty;
+            }
+
+            int start = startIndex + attributeNameLength;
+            int end = data.IndexOf("\"", start, StringComparison.InvariantCultureIgnoreCase);
+            return data.Substring(start, end - start);
+        }
+
+        private static string RemoveAttribute(string data, int startIndex, string attributeName, out int numRemoved)
+        {
+            numRemoved = 0;
+
+            if (startIndex == -1)
+            {
+                return data;
+            }
+
+            int end = data.IndexOf("\"", startIndex + attributeName.Length, StringComparison.InvariantCultureIgnoreCase) + 1;
+            numRemoved = end - startIndex;
+            return data.Remove(startIndex, numRemoved);
+        }
+
+        private static string RemoveXmlProlog(string s, int prefixLength, out int numRemoved)
+        {
+            numRemoved = 0;
+            int startIndex = s.IndexOf("<?xml", 0, prefixLength, StringComparison.OrdinalIgnoreCase);
+            if (startIndex != -1)
+            {
+                int endIndex = s.IndexOf("?>", startIndex, StringComparison.InvariantCultureIgnoreCase);
+                if (endIndex != -1)
+                {
+                    numRemoved = endIndex + 2 - startIndex;
+                    return s.Remove(startIndex, numRemoved);
+                }
+            }
+
+            return s;
+        }
+
+        private static int FindFirstXmlOpenTagIndex(string s)
+        {
+            int index = 0;
+
+            while ((index = s.IndexOf('<', index)) != -1)
+            {
+                if (index < s.Length - 1 && s[index + 1] != '?')
+                {
+                    return index;
+                }
+
+                index++;
+            }
+
+            return -1;
+        }
+
+        private static int FindFirstXmlCloseTagIndex(string s)
+        {
+            int index = 1;
+
+            while ((index = s.IndexOf('>', index)) != -1)
+            {
+                if (index > 0 && s[index - 1] != '?')
+                {
+                    return index;
+                }
+
+                index++;
+            }
+
+            return -1;
+        }
+
         /// <summary>
         /// Add proper
         /// </summary>
@@ -72,49 +154,57 @@ namespace Common.Utilities
         /// <returns>Returns modified svgData with added style</returns>
         public static string AddStyleSVG(string stringSvgData)
         {
-            XElement svgData = XElement.Parse(stringSvgData);
-
-            var attributes = svgData.Attributes();
-            string width = string.Empty;
-            string height = string.Empty;
-            string widthR = string.Empty;
-            string heightR = string.Empty;
-            string oldStyle = string.Empty;
-            bool hasViewBox = false;
-
-            // Get width and height of element and remove it afterwards because it will be added inside style attribute
-            for (int i = 0; i < attributes.Count(); i++)
+            int firstXmlOpenTagIndex = FindFirstXmlOpenTagIndex(stringSvgData);
+            if (firstXmlOpenTagIndex == -1)
             {
-                if (attributes.ElementAt(i).Name == "height")
-                {
-                    height = attributes.ElementAt(i).Value;
-                    attributes.ElementAt(i).Remove();
-                    i--;
-                }
-                else if (attributes.ElementAt(i).Name == "width")
-                {
-                    width = attributes.ElementAt(i).Value;
-                    attributes.ElementAt(i).Remove();
-                    i--;
-                }
-                else if (attributes.ElementAt(i).Name == "style")
-                {
-                    oldStyle = attributes.ElementAt(i).Value;
-                    attributes.ElementAt(i).Remove();
-                    i--;
-                }
-                else if (attributes.ElementAt(i).Name == "viewBox")
-                {
-                    hasViewBox = true;
-                }
+                return stringSvgData;
             }
 
-            svgData.ReplaceAttributes(attributes);
+            int firstXmlCloseTagIndex = FindFirstXmlCloseTagIndex(stringSvgData);
+            if (firstXmlCloseTagIndex == -1)
+            {
+                return stringSvgData;
+            }
+
+            stringSvgData = RemoveXmlProlog(stringSvgData, firstXmlOpenTagIndex, out int numRemoved);
+
+            firstXmlOpenTagIndex -= numRemoved;
+            firstXmlCloseTagIndex -= numRemoved;
+
+            int widthIndex = stringSvgData.IndexOf(WidthAttribute, firstXmlOpenTagIndex, firstXmlCloseTagIndex, StringComparison.InvariantCultureIgnoreCase);
+            int heightIndex = stringSvgData.IndexOf(HeightAttribute, firstXmlOpenTagIndex, firstXmlCloseTagIndex, StringComparison.InvariantCultureIgnoreCase);
+            int styleIndex = stringSvgData.IndexOf(StyleAttribute, firstXmlOpenTagIndex, firstXmlCloseTagIndex, StringComparison.InvariantCultureIgnoreCase);
+
+            string width = GetAttributeValue(WidthAttribute.Length, stringSvgData, widthIndex);
+            string height = GetAttributeValue(HeightAttribute.Length, stringSvgData, heightIndex);
+            string oldStyle = GetAttributeValue(StyleAttribute.Length, stringSvgData, styleIndex);
+
+            bool hasViewBox = stringSvgData.IndexOf(ViewboxAttribute, firstXmlOpenTagIndex, firstXmlCloseTagIndex - firstXmlOpenTagIndex, StringComparison.InvariantCultureIgnoreCase) != -1;
+
+            stringSvgData = RemoveAttribute(stringSvgData, widthIndex, WidthAttribute, out numRemoved);
+            if (heightIndex != -1 && heightIndex > widthIndex)
+            {
+                heightIndex -= numRemoved;
+            }
+
+            if (styleIndex != -1 && styleIndex > widthIndex)
+            {
+                styleIndex -= numRemoved;
+            }
+
+            stringSvgData = RemoveAttribute(stringSvgData, heightIndex, HeightAttribute, out numRemoved);
+            if (styleIndex != -1 && styleIndex > heightIndex)
+            {
+                styleIndex -= numRemoved;
+            }
+
+            stringSvgData = RemoveAttribute(stringSvgData, styleIndex, StyleAttribute, out numRemoved);
 
-            height = CheckUnit(height);
             width = CheckUnit(width);
-            heightR = RemoveUnit(height);
-            widthR = RemoveUnit(width);
+            height = CheckUnit(height);
+
+            string widthR = RemoveUnit(width);
+            string heightR = RemoveUnit(height);
 
             string centering = "position: absolute; top: 50%; left: 50%; transform: translate(-50%, -50%);";
 
@@ -122,16 +212,19 @@ namespace Common.Utilities
             string scaling = $"max-width: {width} ; max-height: {height} ;";
             scaling += $"  _height:expression(this.scrollHeight > {heightR} ? \" {height}\" : \"auto\"); _width:expression(this.scrollWidth > {widthR} ? \"{width}\" : \"auto\");";
 
-            svgData.Add(new XAttribute("style", scaling + centering + oldStyle));
+            string newStyle = $"style=\"{scaling}{centering}{oldStyle}\"";
+            int insertAt = stringSvgData.IndexOf(">", StringComparison.InvariantCultureIgnoreCase);
+
+            stringSvgData = stringSvgData.Insert(insertAt, " " + newStyle);
 
             if (!hasViewBox)
             {
                 // Fixes https://github.com/microsoft/PowerToys/issues/18107
-                string viewBox = $"0 0 {widthR} {heightR}";
-                svgData.Add(new XAttribute("viewBox", viewBox));
+                string viewBox = $"viewBox=\"0 0 {widthR} {heightR}\"";
+                stringSvgData = stringSvgData.Insert(insertAt, " " + viewBox);
             }
 
-            return svgData.ToString();
+            return stringSvgData;
         }
 
         /// <summary>