apacheGH-44096: [C++] Don't use Boost.Process with Emscripten

Because Boost.Process doesn't work with Emscripten.

cpp/src/arrow/testing/process.cc

@@ -18,76 +18,83 @@
 #include "arrow/testing/process.h"
 #include "arrow/result.h"
 
+#define BOOST_PROCESS_AVAILABLE
+#ifdef __EMSCRIPTEN__
+# undef BOOST_PROCESS_AVAILABLE
+#endif
+
+#ifdef BOOST_PROCESS_AVAILABLE
 // This boost/asio/io_context.hpp include is needless for no MinGW
 // build.
 //
 // This is for including boost/asio/detail/socket_types.hpp before any
 // "#include <windows.h>". boost/asio/detail/socket_types.hpp doesn't
 // work if windows.h is already included.
-#include <boost/asio/io_context.hpp>
+# include <boost/asio/io_context.hpp>
 
-#ifdef BOOST_PROCESS_HAVE_V2
+# ifdef BOOST_PROCESS_HAVE_V2
 // We can't use v2 API on Windows because v2 API doesn't support
 // process group [1] and GCS testbench uses multiple processes [2].
 //
 // [1] https://github.com/boostorg/process/issues/259
 // [2] https://github.com/googleapis/storage-testbench/issues/669
-# ifndef _WIN32
-# define BOOST_PROCESS_USE_V2
+# ifndef _WIN32
+# define BOOST_PROCESS_USE_V2
+# endif
 # endif
-#endif
 
-#ifdef BOOST_PROCESS_USE_V2
-# ifdef BOOST_PROCESS_NEED_SOURCE
+# ifdef BOOST_PROCESS_USE_V2
+#  ifdef BOOST_PROCESS_NEED_SOURCE
 // Workaround for https://github.com/boostorg/process/issues/312
-# define BOOST_PROCESS_V2_SEPARATE_COMPILATION
-# ifdef __APPLE__
-# include <sys/sysctl.h>
+# define BOOST_PROCESS_V2_SEPARATE_COMPILATION
+# ifdef __APPLE__
+# include <sys/sysctl.h>
+# endif
+# include <boost/process/v2.hpp>
+# include <boost/process/v2/src.hpp>
+# else
+# include <boost/process/v2.hpp>
 # endif
-# include <boost/process/v2.hpp>
-# include <boost/process/v2/src.hpp>
+# include <unordered_map>
 # else
-# include <boost/process/v2.hpp>
-# endif
-# include <unordered_map>
-#else
 // We need BOOST_USE_WINDOWS_H definition with MinGW when we use
 // boost/process.hpp. boost/process/detail/windows/handle_workaround.hpp
 // doesn't work without BOOST_USE_WINDOWS_H with MinGW because MinGW
 // doesn't provide __kernel_entry without winternl.h.
 //
 // See also:
 // https://github.com/boostorg/process/blob/develop/include/boost/process/detail/windows/handle_workaround.hpp
-# ifdef __MINGW32__
-# define BOOST_USE_WINDOWS_H = 1
-# endif
-# ifdef BOOST_PROCESS_HAVE_V1
-# include <boost/process/v1.hpp>
-# else
-# include <boost/process.hpp>
+# ifdef __MINGW32__
+# define BOOST_USE_WINDOWS_H = 1
+# endif
+# ifdef BOOST_PROCESS_HAVE_V1
+# include <boost/process/v1.hpp>
+# else
+# include <boost/process.hpp>
+# endif
 # endif
-#endif
 
-#ifdef __APPLE__
-# include <limits.h>
-# include <mach-o/dyld.h>
-#endif
+# ifdef __APPLE__
+#  include <limits.h>
+#  include <mach-o/dyld.h>
+# endif
 
-#include <chrono>
-#include <iostream>
-#include <sstream>
-#include <thread>
+# include <chrono>
+# include <iostream>
+# include <sstream>
+# include <thread>
 
-#ifdef BOOST_PROCESS_USE_V2
+# ifdef BOOST_PROCESS_USE_V2
 namespace asio = BOOST_PROCESS_V2_ASIO_NAMESPACE;
 namespace process = BOOST_PROCESS_V2_NAMESPACE;
 namespace filesystem = process::filesystem;
-#elif defined(BOOST_PROCESS_HAVE_V1)
+# elif defined(BOOST_PROCESS_HAVE_V1)
 namespace process = boost::process::v1;
 namespace filesystem = boost::process::v1::filesystem;
-#else
+# else
 namespace process = boost::process;
 namespace filesystem = boost::filesystem;
+# endif
 #endif
 
 namespace arrow::util {
@@ -96,17 +103,20 @@ class Process::Impl {
  public:
  Impl() {
  // Get a copy of the current environment.
-#ifdef BOOST_PROCESS_USE_V2
+#ifdef BOOST_PROCESS_AVAILABLE
+# ifdef BOOST_PROCESS_USE_V2
  for (const auto& kv : process::environment::current()) {
  env_[kv.key()] = process::environment::value(kv.value());
  }
-#else
+# else
  env_ = process::environment(boost::this_process::environment());
+# endif
 #endif
  }
 
  ~Impl() {
-#ifdef BOOST_PROCESS_USE_V2
+#ifdef BOOST_PROCESS_AVAILABLE
+# ifdef BOOST_PROCESS_USE_V2
  // V2 doesn't provide process group support yet:
  // https://github.com/boostorg/process/issues/259
  //
@@ -126,120 +136,150 @@ class Process::Impl {
  }
  }
  }
-#else
+# else
  process_group_ = nullptr;
-#endif
+# endif
  process_ = nullptr;
+#endif
  }
 
  Status SetExecutable(const std::string& name) {
-#ifdef BOOST_PROCESS_USE_V2
+#ifdef BOOST_PROCESS_AVAILABLE
+# ifdef BOOST_PROCESS_USE_V2
  executable_ = process::environment::find_executable(name);
-#else
+# else
  executable_ = process::search_path(name);
-#endif
+# endif
  if (executable_.empty()) {
  // Search the current executable directory as fallback.
  ARROW_ASSIGN_OR_RAISE(auto current_exe, ResolveCurrentExecutable());
-#ifdef BOOST_PROCESS_USE_V2
+# ifdef BOOST_PROCESS_USE_V2
  std::unordered_map<process::environment::key, process::environment::value> env;
  for (const auto& kv : process::environment::current()) {
  env[kv.key()] = process::environment::value(kv.value());
  }
  env["PATH"] = process::environment::value(current_exe.parent_path());
  executable_ = process::environment::find_executable(name, env);
-#else
+# else
  executable_ = process::search_path(name, {current_exe.parent_path()});
-#endif
+# endif
  }
  if (executable_.empty()) {
  return Status::IOError("Failed to find '", name, "' in PATH");
  }
  return Status::OK();
+#else
+ return Status::NotImplemented("Boost.Process isn't available on this system");
+#endif
  }
 
- void SetArgs(const std::vector<std::string>& args) { args_ = args; }
+ void SetArgs(const std::vector<std::string>& args) {
+#ifdef BOOST_PROCESS_AVAILABLE
+ args_ = args;
+#endif
+ }
 
  void SetEnv(const std::string& name, const std::string& value) {
-#ifdef BOOST_PROCESS_USE_V2
+#ifdef BOOST_PROCESS_AVAILABLE
+# ifdef BOOST_PROCESS_USE_V2
  env_[name] = process::environment::value(value);
-#else
+# else
  env_[name] = value;
+# endif
 #endif
  }
 
- void IgnoreStderr() { keep_stderr_ = false; }
+ void IgnoreStderr() {
+#ifdef BOOST_PROCESS_AVAILABLE
+ keep_stderr_ = false;
+#endif
+ }
 
  Status Execute() {
+#ifdef BOOST_PROCESS_AVAILABLE
  try {
-#ifdef BOOST_PROCESS_USE_V2
+# ifdef BOOST_PROCESS_USE_V2
  return ExecuteV2();
-#else
+# else
  return ExecuteV1();
-#endif
+# endif
  } catch (const std::exception& e) {
  return Status::IOError("Failed to launch '", executable_, "': ", e.what());
  }
+#else
+ return Status::NotImplemented("Boost.Process isn't available on this system");
+#endif
  }
 
  bool IsRunning() {
-#ifdef BOOST_PROCESS_USE_V2
+#ifdef BOOST_PROCESS_AVAILABLE
+# ifdef BOOST_PROCESS_USE_V2
  boost::system::error_code error_code;
  return process_ && process_->running(error_code);
-#else
+# else
  return process_ && process_->running();
+# endif
+#else
+ return false;
 #endif
  }
 
  uint64_t pid() {
+#ifdef BOOST_PROCESS_AVAILABLE
  if (!process_) {
  return 0;
  }
  return process_->id();
+#else
+ return 0;
+#endif
  }
 
  private:
+#ifdef BOOST_PROCESS_AVAILABLE
  filesystem::path executable_;
  std::vector<std::string> args_;
  bool keep_stderr_ = true;
-#ifdef BOOST_PROCESS_USE_V2
+# ifdef BOOST_PROCESS_USE_V2
  std::unordered_map<process::environment::key, process::environment::value> env_;
  std::unique_ptr<process::process> process_;
  asio::io_context ctx_;
  // boost/process/v2/ doesn't support process group yet:
  // https://github.com/boostorg/process/issues/259
-#else
+# else
  process::environment env_;
  std::unique_ptr<process::child> process_;
  std::unique_ptr<process::group> process_group_;
+# endif
 #endif
 
+#ifdef BOOST_PROCESS_AVAILABLE
  Result<filesystem::path> ResolveCurrentExecutable() {
  // See https://stackoverflow.com/a/1024937/10194 for various
  // platform-specific recipes.
 
  filesystem::path path;
  boost::system::error_code error_code;
 
-#if defined(__linux__)
+# if defined(__linux__)
  path = filesystem::canonical("/proc/self/exe", error_code);
-#elif defined(__APPLE__)
+# elif defined(__APPLE__)
  char buf[PATH_MAX + 1];
  uint32_t bufsize = sizeof(buf);
  if (_NSGetExecutablePath(buf, &bufsize) < 0) {
  return Status::Invalid("Can't resolve current exe: path too large");
  }
  path = filesystem::canonical(buf, error_code);
-#elif defined(_WIN32)
+# elif defined(_WIN32)
  char buf[MAX_PATH + 1];
  if (!GetModuleFileNameA(NULL, buf, sizeof(buf))) {
  return Status::Invalid("Can't get executable file path");
  }
  path = filesystem::canonical(buf, error_code);
-#else
+# else
  ARROW_UNUSED(error_code);
  return Status::NotImplemented("Not available on this system");
-#endif
+# endif
  if (error_code) {
  // XXX fold this into the Status class?
  return Status::IOError("Can't resolve current exe: ", error_code.message());
@@ -248,7 +288,7 @@ class Process::Impl {
  }
  }
 
-#ifdef BOOST_PROCESS_USE_V2
+# ifdef BOOST_PROCESS_USE_V2
  Status ExecuteV2() {
  process::process_environment env(env_);
  // We can't use std::make_unique<process::process>.
@@ -258,7 +298,7 @@ class Process::Impl {
  : process::process_stdio{{}, {}, nullptr}));
  return Status::OK();
  }
-#else
+# else
  Status ExecuteV1() {
  process_group_ = std::make_unique<process::group>();
  if (keep_stderr_) {
@@ -271,6 +311,7 @@ class Process::Impl {
  }
  return Status::OK();
  }
+# endif
 #endif
 };