CI: Windows MSVC/clang-cl Test using Visual Studio 2022.

This commit introduces Continuous Integration for Windows
with MSVC/clang-cl shipped in Visual Studio 2022.

vcpkg is used to automatically build all dependencies
from source, with the advantage of full automation,
latest upstream version, perfect binary compatibility,
and customizable build flags.

However, the full source build takes a long time (like
using Gentoo Portage or MacPorts), in this case, 2 hours.
A vcpkg binary cache is used to speedup iterative development.
GitHub Actions cache is immutable, we can't modify existing
cache, so we use a last-recently logic: Before each run, the
last-written cache with a given prefix is restored. After
each run, a new cache with the same prefix and a different
suffix is submitted to GitHub. It's GitHub's responsibility
to delete old cache if 7 days have passed or after the total
size exceeds 10 GiB.

Signed-off-by: Yifeng Li <tomli@tomli.me>

Author: biergaizi

.github/workflows/ci.yml

@@ -712,3 +712,130 @@ jobs:
             echo "Unittest CSXCAD Python module execution in venv..."
             cd $GITHUB_WORKSPACE/CSXCAD/python/tests
             python3 -m unittest
+
+  Windows:
+    runs-on: windows-latest
+    needs: Dependencies
+
+    strategy:
+      # Use "false" means a single failed build won't terminate other combinations
+      # in the matrix. This wastes CPU time, but is an important debugging tool to
+      # prevent a single broken platform from stopping the whole matrix.
+      fail-fast: false
+
+      matrix:
+        toolchain:
+          # name: toonchain name (only a name for humans to read).
+          # CC, CXX: C/C++ compiler, environment variables
+          - name: "MSVC"
+            CC: "cl"
+            CXX: "cl"
+
+          - name: "clang-cl"
+            CC: "clang-cl"
+            CXX: "clang-cl"
+
+    env:
+      VS_ROOT_DIR: "C:/Program Files/Microsoft Visual Studio/2022/Enterprise/"
+      CC: "${{ matrix.toolchain.CC }}"
+      CXX: "${{ matrix.toolchain.CXX }}"
+      CFLAGS: "/D_WIN32_WINNT=0x0601"
+      CXXFLAGS: "/D_WIN32_WINNT=0x0601"
+
+      VCPKG_CACHE_PATH: "${{ github.workspace }}/vcpkg-cache/"
+      VCPKG_BINARY_CACHE_PATH: "${{ github.workspace }}/vcpkg-cache/binary"
+      VCPKG_BINARY_SOURCES: "clear;files,${{ github.workspace }}/vcpkg-cache/binary,readwrite"
+      VCPKG_ASSET_CACHE_PATH: "${{ github.workspace }}/vcpkg-cache/asset"
+      X_VCPKG_ASSET_SOURCES: "x-azurl,file://${{ github.workspace }}/vcpkg-cache/asset,readwrite"
+
+    # allow this job to create and modify vcpkg packages for binary cache
+    permissions:
+      packages: write
+
+    name: "Windows (${{ matrix.toolchain.name }}, latest)"
+
+    steps:
+      # When checking out repos, I recommend running actions/checkout
+      # as soon as possible before anything else, and in the reverse
+      # order, from the project repo to its dependencies. This reduces
+      # race conditions due to force pushes (they are harmless but
+      # annoying).
+      - name: Checkout CSXCAD.git
+        uses: actions/checkout@v4
+        with:
+          path: CSXCAD
+          # checkout must be deep, not shallow.
+          # We need tags for "git describe", otherwise build fails.
+          fetch-depth: 0
+
+      - name: ${{ needs.Dependencies.outputs.fparser_checkout_title }}
+        uses: actions/checkout@v4
+        with:
+          repository: "${{ needs.Dependencies.outputs.fparser_repo }}"
+          ref: "${{ needs.Dependencies.outputs.fparser_branch }}"
+          path: fparser
+          # checkout must be deep, not shallow.
+          # We need tags for "git describe", otherwise build fails.
+          fetch-depth: 0
+
+      # It doesn't really work, because MSVC itself doesn't support long path.
+      # But for future-proofing (it does work for clang).
+      - name: Enable long paths
+        run: |
+          New-ItemProperty -Path "HKLM:/SYSTEM/CurrentControlSet/Control/FileSystem" `
+                           -Name "LongPathsEnabled" -Value 1 -PropertyType DWORD -Force
+
+      - name: Create vcpkg cache directories
+        run: |
+          mkdir -p "$env:VCPKG_CACHE_PATH"
+          mkdir -p "$env:VCPKG_BINARY_CACHE_PATH"
+          mkdir -p "$env:VCPKG_ASSET_CACHE_PATH"
+
+      - name: Restore vcpkg cache
+        uses: actions/cache/restore@v5
+        with:
+          path: ${{ env.VCPKG_CACHE_PATH }}
+          # almost always nonexistent
+          key: "Windows - ${{ matrix.toolchain.name }} - ${{ github.sha }}"
+          # use GitHub's fallback feature to pick the latest cache with this prefix
+          restore-keys: |
+            Windows - ${{ matrix.toolchain.name }}
+
+      - name: Build and install fparser
+        run: |
+          & "$env:VS_ROOT_DIR/Common7/Tools/Launch-VsDevShell.ps1" -Arch amd64 -HostArch amd64
+
+          cd "$env:GITHUB_WORKSPACE/fparser"
+          mkdir build && cd build
+          cmake ../ -GNinja -DCMAKE_WINDOWS_EXPORT_ALL_SYMBOLS=ON `
+                    -DCMAKE_BUILD_TYPE=Release `
+                    -DCMAKE_INSTALL_PREFIX="$HOME/opt"
+
+          cmake --build ./ --parallel
+          cmake --install ./ --parallel 8
+
+      - name: Build and install CSXCAD
+        run: |
+          & "$env:VS_ROOT_DIR/Common7/Tools/Launch-VsDevShell.ps1" -Arch amd64 -HostArch amd64
+
+          cd "$env:GITHUB_WORKSPACE/CSXCAD"
+          mkdir build && cd build
+          cmake ../ -GNinja `
+                    -DCMAKE_BUILD_TYPE=Release `
+                    -DCMAKE_INSTALL_PREFIX="$HOME/opt" `
+                    -DFPARSER_ROOT_DIR="$HOME/opt" `
+                    -DCMAKE_TOOLCHAIN_FILE="$env:VCPKG_ROOT/scripts/buildsystems/vcpkg.cmake" `
+                    -DVCPKG_HOST_TRIPLET="x64-windows-release" `
+                    -DVCPKG_TARGET_TRIPLET="x64-windows-release"
+
+          cmake --build ./ --parallel
+          cmake --install ./ --parallel 8
+
+      - name: Save vcpkg cache
+        if: always()  # save even after a build failure.
+        uses: actions/cache/save@v5
+        with:
+          path: ${{ env.VCPKG_CACHE_PATH }}
+          # GitHub cache is immutable and can't be overwritten
+          # save a new cache key every time
+          key: Windows - ${{ matrix.toolchain.name }} - ${{ github.sha }}