gvfs-helper: parallelize POST requests

.github/workflows/scalar-functional-tests.yml

@@ -43,6 +43,24 @@ jobs:
         if: runner.os == 'Windows'
         uses: git-for-windows/setup-git-for-windows-sdk@v2
 
+      - name: Update the Git wrapper for UCRT64
+        if: runner.os == 'Windows'
+        shell: pwsh
+        run: |
+          # Only needed for the MINGW64 to UCRT64 transition, until
+          # Actions runners ship Git for Windows v2.56.0 final.
+          if ($env:MSYSTEM -eq 'UCRT64' -and
+              !(Test-Path 'C:\Program Files\Git\ucrt64')) {
+            $url = 'https://github.com/git-for-windows/git/releases'
+            $url += '/download/v2.56.0-rc0.windows.1'
+            $zip = Join-Path $env:RUNNER_TEMP 'MinGit.zip'
+            Invoke-WebRequest -Uri "$url/MinGit-2.56.0-rc0-64-bit.zip" `
+              -OutFile $zip
+            & "$env:SystemRoot\System32\tar.exe" -xf $zip `
+              -C 'C:\Program Files\Git' cmd/git.exe cmd/scalar.exe
+            if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+          }
+
       - name: Provide a minimal `install` on Windows
         if: runner.os == 'Windows'
         shell: bash

.github/workflows/vfs-functional-tests.yml

@@ -99,6 +99,13 @@ jobs:
 
           make -j5 DESTDIR="$GITHUB_WORKSPACE/MicrosoftGit/payload/${{ matrix.architecture }}" install
 
+          # The test runners still ship the MINGW64 runtime.
+          if test "$MSYSTEM" = UCRT64
+          then
+            cp /ucrt64/bin/*.dll \
+              "$GITHUB_WORKSPACE/MicrosoftGit/payload/x86_64/ucrt64/bin/"
+          fi
+
       - name: Upload Git artifact
         uses: actions/upload-artifact@v7
         with:
@@ -136,6 +143,18 @@ jobs:
           ) else (
             set GIT_PAYLOAD=%~dp0payload\x86_64
           )
+          rem Only needed for the MINGW64 to UCRT64 transition, until
+          rem Actions runners ship Git for Windows v2.56.0 final.
+          if not exist "%GIT_PAYLOAD%\ucrt64\bin\git.exe" goto install_git
+          if exist "C:\Program Files\Git\ucrt64" goto install_git
+          set "MINGIT_URL=https://github.com/git-for-windows/git/releases"
+          set "MINGIT_URL=%MINGIT_URL%/download/v2.56.0-rc0.windows.1"
+          "%SYSTEMROOT%\System32\curl.exe" -fL ^
+            "%MINGIT_URL%/MinGit-2.56.0-rc0-64-bit.zip" ^
+            -o "%RUNNER_TEMP%\MinGit.zip" || exit /b 1
+          "%SYSTEMROOT%\System32\tar.exe" -xf "%RUNNER_TEMP%\MinGit.zip" ^
+            -C "C:\Program Files\Git" cmd/git.exe || exit /b 1
+          :install_git
           echo Installing Git from %GIT_PAYLOAD% to "C:\Program Files\Git"...
           robocopy "%GIT_PAYLOAD%" "C:\Program Files\Git" /E /NFL /NDL /NJH /NJS /NS /NC
           if %ERRORLEVEL% GEQ 8 exit /b %ERRORLEVEL%

Documentation/config/gvfs.adoc

@@ -55,3 +55,14 @@ gvfs.prefetchThreads::
 	index-pack execution, which can significantly speed up the
 	installation of multiple prefetch packs. Values less than `1` are
 	treated as `1`.
+
+gvfs.postThreads::
+	Set the number of parallel workers used when fetching objects
+	via HTTP POST requests. Each worker creates its own HTTP
+	connection and streams the response directly into an
+	`index-pack --stdin` child process. The default value is `1`,
+	which processes POST requests sequentially using the existing
+	code path. Setting this to a higher value (for example `4`)
+	downloads multiple batches of objects concurrently when the POST
+	block size is at least `100`. Values less than `1` are treated as
+	`1`.

contrib/buildsystems/CMakeLists.txt

@@ -284,7 +284,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
 				OVERRIDE_STRDUP MMAP_PREVENTS_DELETE USE_WIN32_MMAP
 				HAVE_WPGMPTR HAVE_RTLGENRANDOM)
 	if(CMAKE_GENERATOR_PLATFORM STREQUAL "x64")
-		add_compile_definitions(ENSURE_MSYSTEM_IS_SET="MINGW64" MINGW_PREFIX="mingw64")
+		add_compile_definitions(ENSURE_MSYSTEM_IS_SET="UCRT64" MINGW_PREFIX="ucrt64")
 	elseif(CMAKE_GENERATOR_PLATFORM STREQUAL "arm64")
 		add_compile_definitions(ENSURE_MSYSTEM_IS_SET="CLANGARM64" MINGW_PREFIX="clangarm64")
 	elseif(CMAKE_GENERATOR_PLATFORM STREQUAL "x86")