build: resolve protoc from vcpkg at runtime

Author: Xuanwo

CMakeLists.txt

@@ -104,26 +104,21 @@ set(RUST_FFI_DEPENDS
     ${CMAKE_CURRENT_LIST_DIR}/rust/lib.rs
     ${CMAKE_CURRENT_LIST_DIR}/rust/scanner.rs
     ${CMAKE_CURRENT_LIST_DIR}/rust/types.rs
-    ${CMAKE_CURRENT_LIST_DIR}/rust/writer.rs)
+    ${CMAKE_CURRENT_LIST_DIR}/rust/writer.rs
+    ${CMAKE_CURRENT_LIST_DIR}/scripts/protoc_wrapper.sh
+    ${CMAKE_CURRENT_LIST_DIR}/scripts/protoc_wrapper.cmd)
 
 set(PROTOC_BIN "")
-if(DEFINED ENV{VCPKG_ROOT})
-  if(DEFINED ENV{VCPKG_HOST_TRIPLET})
-    set(PROTOC_BIN "$ENV{VCPKG_ROOT}/installed/$ENV{VCPKG_HOST_TRIPLET}/tools/protobuf/protoc")
-  elseif(DEFINED ENV{VCPKG_TARGET_TRIPLET})
-    set(PROTOC_BIN "$ENV{VCPKG_ROOT}/installed/$ENV{VCPKG_TARGET_TRIPLET}/tools/protobuf/protoc")
-  endif()
-endif()
-if(WIN32 AND NOT PROTOC_BIN STREQUAL "" AND NOT PROTOC_BIN MATCHES "\\.exe$")
-  set(PROTOC_BIN "${PROTOC_BIN}.exe")
+if(WIN32)
+  set(PROTOC_BIN "${CMAKE_CURRENT_LIST_DIR}/scripts/protoc_wrapper.cmd")
+else()
+  set(PROTOC_BIN "${CMAKE_CURRENT_LIST_DIR}/scripts/protoc_wrapper.sh")
 endif()
 
 set(RUST_CARGO_ENV
     CARGO_TARGET_DIR=${RUST_TARGET_DIR}
     MACOSX_DEPLOYMENT_TARGET=${CMAKE_OSX_DEPLOYMENT_TARGET})
-if(NOT PROTOC_BIN STREQUAL "")
-  list(APPEND RUST_CARGO_ENV PROTOC=${PROTOC_BIN})
-endif()
+list(APPEND RUST_CARGO_ENV PROTOC=${PROTOC_BIN})
 
 # Building both debug and release Rust artifacts is expensive and can trigger OOMs in CI.
 # For single-config generators (Ninja/Makefiles), only build the active configuration's artifact.

scripts/protoc_wrapper.cmd

@@ -0,0 +1,42 @@
+@echo off
+setlocal
+
+if not "%PROTOC_REAL%"=="" (
+  if exist "%PROTOC_REAL%" (
+    "%PROTOC_REAL%" %*
+    exit /b %errorlevel%
+  )
+)
+
+set "VCPKG_ROOT=%VCPKG_ROOT%"
+if "%VCPKG_ROOT%"=="" goto :fallback
+
+set "TRIPLET=%VCPKG_HOST_TRIPLET%"
+if "%TRIPLET%"=="" set "TRIPLET=%VCPKG_TARGET_TRIPLET%"
+if "%TRIPLET%"=="" goto :fallback
+
+set "BASE1=%VCPKG_ROOT%\\installed\\%TRIPLET%\\tools\\protobuf"
+for %%F in ("%BASE1%\\protoc.exe" "%BASE1%\\protoc-*.exe") do (
+  if exist "%%~fF" (
+    "%%~fF" %*
+    exit /b %errorlevel%
+  )
+)
+
+set "BASE2=%VCPKG_ROOT%\\packages\\protobuf_%TRIPLET%\\tools\\protobuf"
+for %%F in ("%BASE2%\\protoc.exe" "%BASE2%\\protoc-*.exe") do (
+  if exist "%%~fF" (
+    "%%~fF" %*
+    exit /b %errorlevel%
+  )
+)
+
+:fallback
+where protoc >nul 2>nul
+if %errorlevel%==0 (
+  protoc %*
+  exit /b %errorlevel%
+)
+
+echo protoc_wrapper: protoc not found 1>&2
+exit /b 127

scripts/protoc_wrapper.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env sh
+set -eu
+
+if [ -n "${PROTOC_REAL:-}" ] && [ -x "${PROTOC_REAL}" ]; then
+  exec "${PROTOC_REAL}" "$@"
+fi
+
+vcpkg_root="${VCPKG_ROOT:-}"
+host_triplet="${VCPKG_HOST_TRIPLET:-${VCPKG_TARGET_TRIPLET:-}}"
+
+if [ -n "${vcpkg_root}" ] && [ -n "${host_triplet}" ]; then
+  for candidate in \
+    "${vcpkg_root}/installed/${host_triplet}/tools/protobuf/protoc" \
+    "${vcpkg_root}/installed/${host_triplet}/tools/protobuf/protoc-"* \
+    "${vcpkg_root}/packages/protobuf_${host_triplet}/tools/protobuf/protoc" \
+    "${vcpkg_root}/packages/protobuf_${host_triplet}/tools/protobuf/protoc-"*; do
+    if [ -x "${candidate}" ]; then
+      exec "${candidate}" "$@"
+    fi
+  done
+fi
+
+if command -v protoc >/dev/null 2>&1; then
+  exec protoc "$@"
+fi
+
+echo "protoc_wrapper: protoc not found (VCPKG_ROOT=${vcpkg_root} VCPKG_HOST_TRIPLET=${host_triplet})" >&2
+exit 127