[Copilot] Add FlatBuffer runtime interpreter for Lottie animations

.github/workflows/dotnet-build.yml

@@ -33,12 +33,6 @@ jobs:
           fetch-depth: 0
           submodules: true
 
-      # Set up a VS build environment.
-      - name: Setup Environment Variables
-        run: |
-          "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\Common7\Tools\VsDevCmd.bat" -no_logo
-        shell: cmd
-
       # Install NuGet tools.  
       - name: Setup NuGet
         uses: NuGet/setup-nuget@v2
@@ -172,4 +166,4 @@ jobs:
           **/*.nupkg
           --source https://api.nuget.org/v3/index.json
           --api-key ${{ secrets.NUGET_PACKAGE_PUSH_TOKEN }}
-          --skip-duplicate
+          --skip-duplicate

.gitignore

@@ -238,3 +238,7 @@ launchSettings.json
 
 # Nuget Package files.
 pack/
+
+# Native dependencies restored by MSBuild.
+/.vcpkg/
+/vcpkg_installed/

Directory.Build.props

@@ -125,7 +125,7 @@
   </Choose>
 
   <Choose>
-    <When Condition="'$(IsTestProject)' != 'true' and '$(IsSampleProject)' != 'true' and '$(IsDesignProject)' != 'true'">
+    <When Condition="'$(MSBuildProjectExtension)' == '.csproj' and '$(IsTestProject)' != 'true' and '$(IsSampleProject)' != 'true' and '$(IsDesignProject)' != 'true'">
       <ItemGroup>
         <PackageReference Include="Microsoft.VisualStudio.Threading.Analyzers" Version="17.5.22" PrivateAssets="all" />
         <PackageReference Include="StyleCop.Analyzers" Version="1.1.118" PrivateAssets="all" />
@@ -144,7 +144,7 @@
     <NoWarn>$(NoWarn);8002</NoWarn>
   </PropertyGroup>
 
-  <ItemGroup>
+  <ItemGroup Condition="'$(MSBuildProjectExtension)' == '.csproj'">
     <PackageReference Include="Nerdbank.GitVersioning" Version="3.5.119" PrivateAssets="all" />
   </ItemGroup>
 

Lottie-Windows.sln

@@ -173,6 +173,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LottieSamples", "LottieSamp
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Lottie-Windows-UwpNET", "Lottie-Windows\Lottie-Windows-UwpNET\Lottie-Windows-UwpNET.csproj", "{FA1977D8-5C6F-DF3A-0926-C12A1A415024}"
 EndProject
+Project("{BC8A1FFA-BEE3-4634-8014-F334798102B3}") = "LottieRuntimeTool", "source\LottieRuntime\LottieRuntimeTool.vcxproj", "{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		BETA|Any CPU = BETA|Any CPU
@@ -192,6 +194,27 @@ Global
 		Release|x86 = Release|x86
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|Any CPU.ActiveCfg = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|ARM.ActiveCfg = Release|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|ARM64.ActiveCfg = Release|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|ARM64.Build.0 = Release|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|x64.ActiveCfg = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|x64.Build.0 = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.BETA|x86.ActiveCfg = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|Any CPU.ActiveCfg = Debug|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|ARM.ActiveCfg = Debug|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|ARM64.ActiveCfg = Debug|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|ARM64.Build.0 = Debug|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|x64.ActiveCfg = Debug|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|x64.Build.0 = Debug|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Debug|x86.ActiveCfg = Debug|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|Any CPU.ActiveCfg = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|ARM.ActiveCfg = Release|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|ARM64.ActiveCfg = Release|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|ARM64.Build.0 = Release|ARM64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|x64.ActiveCfg = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|x64.Build.0 = Release|x64
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48}.Release|x86.ActiveCfg = Release|x64
 		{5120EFD7-A556-46BF-8D56-F65F1EF9A305}.BETA|Any CPU.ActiveCfg = BETA|x86
 		{5120EFD7-A556-46BF-8D56-F65F1EF9A305}.BETA|ARM.ActiveCfg = BETA|ARM
 		{5120EFD7-A556-46BF-8D56-F65F1EF9A305}.BETA|ARM.Build.0 = BETA|ARM
@@ -685,6 +708,7 @@ Global
 		{FC89273A-B2DA-4625-8A73-EF02A658D65E} = {AB232F35-AAF7-4AE2-B1D2-45DD9BC2F7D7}
 		{7654A857-9A99-4185-9F8E-DD0CE662AF23} = {AB232F35-AAF7-4AE2-B1D2-45DD9BC2F7D7}
 		{DC7F7A39-B7A7-40B4-937A-601460CAE38C} = {AB232F35-AAF7-4AE2-B1D2-45DD9BC2F7D7}
+		{9A7B4C2E-1F3D-4B7A-9C3E-2D5A8F0B2E48} = {AB232F35-AAF7-4AE2-B1D2-45DD9BC2F7D7}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {51B9BB4C-5196-41CF-950C-12B04AD8A61C}

LottieGen/DotnetTool/LottieGen.csproj

@@ -9,7 +9,9 @@
     <IsPackable>true</IsPackable>
     <PackAsTool>true</PackAsTool>
     <ToolCommandName>LottieGen</ToolCommandName>
+    <FlatBuffersVcpkgTriplet Condition="'$(FlatBuffersVcpkgTriplet)' == ''">x64-windows</FlatBuffersVcpkgTriplet>
   </PropertyGroup>
+  <Import Project="..\..\build\FlatBuffers.targets" />
 
   <PropertyGroup>
     <_SourceDir>..\..\source\</_SourceDir>
@@ -18,6 +20,7 @@
 
   <Import Project="..\Common.proj" />
   <Import Project="$(_SourceDir)Animatables\Animatables.projitems" Label="Shared" />
+  <Import Project="$(_SourceDir)CompDataFlatbuffer\CompDataFlatbuffer.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)CompMetadata\CompMetadata.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)DotLottie\DotLottie.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)GenericData\GenericData.projitems" Label="Shared" />
@@ -33,4 +36,32 @@
   <Import Project="$(_SourceDir)WinUIXamlMediaData\WinUIXamlMediaData.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)YamlData\YamlData.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)UIDataCodeGen\UIDataCodeGen.projitems" Label="Shared" />
+  <ItemGroup>
+    <PackageReference Include="Google.FlatBuffers" Version="25.2.10" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="..\..\source\LottieRuntime\LottieRuntime.h" Pack="true" PackagePath="inc\lottiecomp\" />
+    <None Include="..\..\source\LottieRuntime\LottieVisualSource.h" Pack="true" PackagePath="inc\lottiecomp\" />
+    <None Include="..\..\source\LottieRuntime\LottieRuntime.cpp" Pack="true" PackagePath="LottieRuntime\" />
+    <None Include="..\..\source\LottieRuntime\LottieVisualSource.cpp" Pack="true" PackagePath="LottieRuntime\" />
+    <None Include="..\..\source\LottieRuntime\README.md" Pack="true" PackagePath="LottieRuntime\" />
+    <None Include="..\..\source\LottieRuntime\Generated\lottie_comp_generated.h" Pack="true" PackagePath="inc\lottiecomp\Generated\" />
+    <None Include="..\..\source\LottieFlatbuffer\lottie_comp.fbs" Pack="true" PackagePath="LottieRuntime\" />
+    <None Include="..\..\LICENSE.md" Pack="true" PackagePath="LottieRuntime\" />
+  </ItemGroup>
+
+  <Target Name="CollectLottieRuntimePackageContent" BeforeTargets="_GetPackageFiles"
+          DependsOnTargets="RestoreFlatBuffers">
+    <Error Condition="!Exists('$(FlatBuffersVcpkgInstalledDir)\$(FlatBuffersVcpkgTriplet)\share\flatbuffers\copyright')"
+           Text="The restored FlatBuffers license is required to package LottieGen." />
+    <Copy SourceFiles="$(FlatBuffersVcpkgInstalledDir)\$(FlatBuffersVcpkgTriplet)\share\flatbuffers\copyright"
+          DestinationFiles="$(IntermediateOutputPath)flatbuffers.LICENSE.txt" />
+    <ItemGroup>
+      <None Include="$(FlatBuffersIncludeDirectory)\flatbuffers\**\*"
+            Pack="true" PackagePath="inc\lottiecomp\flatbuffers\%(RecursiveDir)" />
+      <None Include="$(IntermediateOutputPath)flatbuffers.LICENSE.txt"
+            Pack="true" PackagePath="LottieRuntime\" />
+    </ItemGroup>
+  </Target>
 </Project>

LottieGen/MSBuildTask/LottieGen.cs

@@ -42,7 +42,7 @@ public sealed class LottieGen : Microsoft.Build.Utilities.ToolTask
         public string? InputFile { get; set; }
 
         /// <summary>
-        /// cs, cppcx, or cppwinrt.
+        /// cs, cppcx, cppwinrt, or flatbuffer.
         /// </summary>
         [Required]
         public string? Language { get; set; }
@@ -190,6 +190,13 @@ public override bool Execute()
                         }
 
                         break;
+
+                    case Lang.Flatbuffer:
+                        // The number of .lcomp variants depends on the UAP versions
+                        // required by the animation, so use the paths LottieGen reported.
+                        OutputFiles = _outputFiles.ConvertAll(f => (ITaskItem)new TaskItem(f)).ToArray();
+                        break;
+
                     default:
                         throw new InvalidOperationException();
                 }
@@ -341,6 +348,7 @@ protected override bool ValidateParameters()
                 case Lang.Cppwinrt:
                 case Lang.CSharp:
                 case Lang.Cx:
+                case Lang.Flatbuffer:
                     break;
 
                 default:
@@ -379,7 +387,8 @@ protected override void LogEventsFromTextOutput(string singleLine, MessageImport
                 singleLine.StartsWith("C# code for class ") ||
                 singleLine.StartsWith("Cppwinrt header for class ") ||
                 singleLine.StartsWith("Cppwinrt source for class ") ||
-                singleLine.StartsWith("Cppwinrt IDL for class ");
+                singleLine.StartsWith("Cppwinrt IDL for class ") ||
+                singleLine.StartsWith("Flatbuffer data for class ");
         }
 
         Lang GetNormalizedLanguage()
@@ -397,6 +406,9 @@ Lang GetNormalizedLanguage()
                 case "cx":
                     return Lang.Cx;
 
+                case "flatbuffer":
+                    return Lang.Flatbuffer;
+
                 default:
                     return Lang.Unknown;
             }
@@ -408,6 +420,7 @@ enum Lang
             CSharp,
             Cx,
             Cppwinrt,
+            Flatbuffer,
         }
     }
 }

LottieGen/win-x64/LottieGen.win-x64.csproj

@@ -35,6 +35,7 @@
 
   <Import Project="..\Common.proj" />
   <Import Project="$(_SourceDir)Animatables\Animatables.projitems" Label="Shared" />
+  <Import Project="$(_SourceDir)CompDataFlatbuffer\CompDataFlatbuffer.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)CompMetadata\CompMetadata.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)DotLottie\DotLottie.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)GenericData\GenericData.projitems" Label="Shared" />
@@ -50,4 +51,7 @@
   <Import Project="$(_SourceDir)WinUIXamlMediaData\WinUIXamlMediaData.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)YamlData\YamlData.projitems" Label="Shared" />
   <Import Project="$(_SourceDir)UIDataCodeGen\UIDataCodeGen.projitems" Label="Shared" />
+  <ItemGroup>
+    <PackageReference Include="Google.FlatBuffers" Version="25.2.10" />
+  </ItemGroup>
 </Project>

README.md

@@ -13,6 +13,12 @@ Lottie-Windows consists of 3 related products:
 
 This repo also contains source code for **[samples](/LottieViewer)**.
 
+It also contains **[LottieRuntime](/source/LottieRuntime)**, native C++/WinRT source that
+builds the composition tree at runtime from a serialized animation produced by
+`LottieGen -Language flatbuffer`. It keeps the animation as data, like the JSON path does, but
+without shipping a JSON parser or the translator. See
+[the format](/source/LottieFlatbuffer/README.md) for how the two relate.
+
 ## <a name="quickstart"></a> Quick start
 
 There are **two** options to integrate Lottie animations into your **WinUI 3** or **UWP** project.

build/FlatBuffers.targets

@@ -0,0 +1,27 @@
+<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup>
+    <_FlatBuffersRepoRoot>$(MSBuildThisFileDirectory)..\</_FlatBuffersRepoRoot>
+    <_RestoreFlatBuffers Condition="'$(FlatBuffersIncludeDirectory)' == ''">true</_RestoreFlatBuffers>
+    <FlatBuffersVcpkgRoot Condition="'$(FlatBuffersVcpkgRoot)' == '' and '$(VcpkgRoot)' != ''">$(VcpkgRoot)</FlatBuffersVcpkgRoot>
+    <FlatBuffersVcpkgRoot Condition="'$(FlatBuffersVcpkgRoot)' == '' and '$(VCPKG_ROOT)' != ''">$(VCPKG_ROOT)</FlatBuffersVcpkgRoot>
+    <FlatBuffersVcpkgRoot Condition="'$(FlatBuffersVcpkgRoot)' == '' and Exists('$(VSInstallRoot)\VC\vcpkg\vcpkg.exe')">$(VSInstallRoot)\VC\vcpkg</FlatBuffersVcpkgRoot>
+    <FlatBuffersVcpkgRoot Condition="'$(FlatBuffersVcpkgRoot)' == ''">$(_FlatBuffersRepoRoot).vcpkg</FlatBuffersVcpkgRoot>
+    <FlatBuffersVcpkgInstalledDir Condition="'$(FlatBuffersVcpkgInstalledDir)' == ''">$(_FlatBuffersRepoRoot)vcpkg_installed</FlatBuffersVcpkgInstalledDir>
+    <FlatBuffersVcpkgTriplet Condition="'$(FlatBuffersVcpkgTriplet)' == '' and '$(Platform)' == 'x64'">x64-windows</FlatBuffersVcpkgTriplet>
+    <FlatBuffersVcpkgTriplet Condition="'$(FlatBuffersVcpkgTriplet)' == '' and '$(Platform)' == 'ARM64'">arm64-windows</FlatBuffersVcpkgTriplet>
+    <FlatBuffersVcpkgHostTriplet Condition="'$(FlatBuffersVcpkgHostTriplet)' == '' and ('$(PROCESSOR_ARCHITECTURE)' == 'ARM64' or '$(PROCESSOR_ARCHITEW6432)' == 'ARM64')">arm64-windows</FlatBuffersVcpkgHostTriplet>
+    <FlatBuffersVcpkgHostTriplet Condition="'$(FlatBuffersVcpkgHostTriplet)' == ''">x64-windows</FlatBuffersVcpkgHostTriplet>
+    <FlatBuffersIncludeDirectory Condition="'$(_RestoreFlatBuffers)' == 'true'">$(FlatBuffersVcpkgInstalledDir)\$(FlatBuffersVcpkgTriplet)\include</FlatBuffersIncludeDirectory>
+  </PropertyGroup>
+
+  <!-- Invoke vcpkg explicitly so a first-build bootstrap works without evaluation-time imports. -->
+  <Target Name="RestoreFlatBuffers" BeforeTargets="$(FlatBuffersRestoreBeforeTargets)"
+          Condition="'$(DesignTimeBuild)' != 'true'">
+    <Error Condition="'$(_RestoreFlatBuffers)' == 'true' and '$(FlatBuffersVcpkgTriplet)' == ''"
+           Text="Set FlatBuffersVcpkgTriplet for platform '$(Platform)'. Supported defaults are x64 and ARM64." />
+    <Exec Condition="'$(_RestoreFlatBuffers)' == 'true'"
+          Command="powershell.exe -NoProfile -ExecutionPolicy Bypass -File &quot;$(MSBuildThisFileDirectory)RestoreFlatBuffers.ps1&quot; -VcpkgRoot &quot;$(FlatBuffersVcpkgRoot)\.&quot; -InstalledDir &quot;$(FlatBuffersVcpkgInstalledDir)\.&quot; -Triplet &quot;$(FlatBuffersVcpkgTriplet)&quot; -HostTriplet &quot;$(FlatBuffersVcpkgHostTriplet)&quot;" />
+    <Error Condition="!Exists('$(FlatBuffersIncludeDirectory)\flatbuffers\flatbuffers.h')"
+           Text="FlatBuffers headers were not found at '$(FlatBuffersIncludeDirectory)'. Restore vcpkg dependencies or set FlatBuffersIncludeDirectory to the include directory for FlatBuffers 25.2.10." />
+  </Target>
+</Project>

build/RegenerateFlatbuffers.ps1

@@ -0,0 +1,49 @@
+# Regenerates the FlatBuffers code for lottie_comp.fbs.
+#
+# The generated C# and C++ sources are checked in so that contributors do not
+# need flatc installed in order to build. Run this script after any change to
+# source/LottieFlatbuffer/lottie_comp.fbs, and check in the result.
+#
+[CmdletBinding()]
+param(
+    [string]$VcpkgRoot = $env:VCPKG_ROOT,
+
+    [string]$InstalledDir = (Join-Path $PSScriptRoot "..\vcpkg_installed"),
+
+    [string]$HostTriplet = $(if ($env:PROCESSOR_ARCHITECTURE -eq "ARM64" -or $env:PROCESSOR_ARCHITEW6432 -eq "ARM64") { "arm64-windows" } else { "x64-windows" })
+)
+
+$ErrorActionPreference = "Stop"
+
+$repoRoot = Resolve-Path (Join-Path $PSScriptRoot "..")
+$schema = Join-Path $repoRoot "source\LottieFlatbuffer\lottie_comp.fbs"
+$csharpOut = Join-Path $repoRoot "source\CompDataFlatbuffer\Generated"
+$cppOut = Join-Path $repoRoot "source\LottieRuntime\Generated"
+
+if (!$VcpkgRoot) {
+    $VcpkgRoot = Join-Path $repoRoot ".vcpkg"
+}
+
+& (Join-Path $PSScriptRoot "RestoreFlatBuffers.ps1") -VcpkgRoot $VcpkgRoot `
+    -InstalledDir $InstalledDir -Triplet $HostTriplet -HostTriplet $HostTriplet
+$flatc = Join-Path $InstalledDir "$HostTriplet\tools\flatbuffers\flatc.exe"
+
+New-Item -ItemType Directory -Force -Path $csharpOut, $cppOut | Out-Null
+
+# --gen-onefile keeps the checked in C# to a single file rather than one file
+# per type spread over a namespace directory tree.
+& $flatc --csharp --gen-onefile -o $csharpOut $schema
+if ($LASTEXITCODE -ne 0) { throw "flatc failed to generate C#." }
+
+& $flatc --cpp --scoped-enums -o $cppOut $schema
+if ($LASTEXITCODE -ne 0) { throw "flatc failed to generate C++." }
+
+foreach ($path in @(
+    (Join-Path $csharpOut "lottie_comp_generated.cs"),
+    (Join-Path $cppOut "lottie_comp_generated.h")
+)) {
+    $contents = [IO.File]::ReadAllText($path)
+    [IO.File]::WriteAllText($path, ($contents -replace '\r?\n', "`r`n"), [Text.UTF8Encoding]::new($false))
+}
+
+Write-Host "Generated FlatBuffers code from $schema"

build/RestoreFlatBuffers.ps1

@@ -0,0 +1,67 @@
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory)]
+    [string]$VcpkgRoot,
+
+    [Parameter(Mandatory)]
+    [string]$InstalledDir,
+
+    [Parameter(Mandatory)]
+    [string]$Triplet,
+
+    [string]$HostTriplet = "x64-windows"
+)
+
+$ErrorActionPreference = "Stop"
+$repoRoot = [IO.Path]::GetFullPath((Join-Path $PSScriptRoot ".."))
+$VcpkgRoot = [IO.Path]::GetFullPath($VcpkgRoot)
+$InstalledDir = [IO.Path]::GetFullPath($InstalledDir)
+$localRoot = Join-Path $repoRoot ".vcpkg"
+$vcpkg = Join-Path $VcpkgRoot "vcpkg.exe"
+$baseline = (Get-Content (Join-Path $repoRoot "vcpkg.json") -Raw | ConvertFrom-Json).'builtin-baseline'
+
+function Invoke-Checked([string]$Program, [string[]]$Arguments) {
+    & $Program @Arguments
+    if ($LASTEXITCODE -ne 0) {
+        throw "'$Program $($Arguments -join ' ')' failed with exit code $LASTEXITCODE."
+    }
+}
+
+if (!(Test-Path -LiteralPath $vcpkg)) {
+    if ($VcpkgRoot -ne $localRoot) {
+        throw "vcpkg.exe was not found at '$VcpkgRoot'. Bootstrap that installation or omit FlatBuffersVcpkgRoot to use automatic discovery."
+    }
+
+    if (!(Test-Path -LiteralPath $VcpkgRoot)) {
+        Invoke-Checked "git" @("init", $VcpkgRoot)
+        Invoke-Checked "git" @("-C", $VcpkgRoot, "remote", "add", "origin", "https://github.com/microsoft/vcpkg.git")
+    }
+
+    $remote = & git -C $VcpkgRoot remote get-url origin
+    if ($LASTEXITCODE -ne 0 -or $remote -ne "https://github.com/microsoft/vcpkg.git") {
+        throw "'$VcpkgRoot' must be a checkout of https://github.com/microsoft/vcpkg.git."
+    }
+
+    Invoke-Checked "git" @("-C", $VcpkgRoot, "fetch", "origin", $baseline)
+    Invoke-Checked "git" @("-C", $VcpkgRoot, "checkout", "--detach", $baseline)
+    Invoke-Checked (Join-Path $VcpkgRoot "bootstrap-vcpkg.bat") @("-disableMetrics")
+}
+
+if ($VcpkgRoot -eq $localRoot) {
+    $shallow = & git -C $VcpkgRoot rev-parse --is-shallow-repository
+    if ($LASTEXITCODE -ne 0) {
+        throw "Could not inspect the repo-local vcpkg checkout at '$VcpkgRoot'."
+    }
+    if ($shallow -eq "true") {
+        Invoke-Checked "git" @("-C", $VcpkgRoot, "fetch", "--unshallow", "origin", $baseline)
+    }
+}
+
+Invoke-Checked $vcpkg @(
+    "install",
+    "--triplet=$Triplet",
+    "--host-triplet=$HostTriplet",
+    "--x-wait-for-lock",
+    "--x-manifest-root=$repoRoot",
+    "--x-install-root=$InstalledDir"
+)

build/build.cake

@@ -101,6 +101,8 @@ static bool IsExcludedDirectory(FilePath path)
     return
         segments.Contains("bin") ||
         segments.Contains("external") ||
+        segments.Contains(".vcpkg") ||
+        segments.Contains("vcpkg_installed") ||
         segments.Contains("internal") ||
         segments.Contains("obj");
 }