Enable basic windows support (#33)

* windows: fix implementation error
- repair configure_pipe
- allow vector initialization
- add draft destructor
- close pipes correctly

* windows: add some test compatibility

* windows: update readme

* windows: add vector args to check_output

Author: xoviat

README.md

@@ -13,8 +13,10 @@ This library had these design goals:
 
 
 ## Supported Platforms
-Unlike python2.7 subprocess module, this library currently only supports MAC OS and Linux.
-It has no support for Windows in its current state.
+This library supports MAC OS and Linux.
+
+Support for Windows is limited at this time. Please report any specific use-cases that fail,
+and they will be fixed as they are reported.
 
 ## Integration
 Subprocess library has just a single source `subprocess.hpp` present at the top directory of this repository. All you need to do is add
@@ -34,6 +36,7 @@ Checkout http://templated-thoughts.blogspot.in/2016/03/sub-processing-with-moder
 ## Compiler Support
 Linux - g++ 4.8 and above
 Mac OS - Clang 3.4 and later 
+Windows - MSVC 2015 and above
 
 ## Examples
 Here are few examples to show how to get started:

subprocess.hpp

@@ -272,11 +272,11 @@ namespace util
 
     // Create a pipe for the child process's STDIN.
     if (!CreatePipe(read_handle, write_handle, &saAttr,0))
-      throw OSError("Stdin CreatePipe", 0);
+      throw OSError("CreatePipe", 0);
 
     // Ensure the write handle to the pipe for STDIN is not inherited.
-    if (!SetHandleInformation(child_handle, HANDLE_FLAG_INHERIT, 0))
-      throw OSError("Stdin SetHandleInformation", 0);
+    if (!SetHandleInformation(*child_handle, HANDLE_FLAG_INHERIT, 0))
+      throw OSError("SetHandleInformation", 0);
   }
 #endif
 
@@ -1131,6 +1131,26 @@ class Popen
     if (!defer_process_start_) execute_process();
   }
 
+  template <typename... Args>
+  Popen(std::vector<std::string> vargs_, Args &&... args) : vargs_(vargs_)
+  {
+    init_args(std::forward<Args>(args)...);
+
+    // Setup the communication channels of the Popen class
+    stream_.setup_comm_channels();
+
+    if (!defer_process_start_) execute_process();
+  }
+
+/*
+  ~Popen()
+  {
+#ifdef _MSC_VER
+    CloseHandle(this->process_handle_);
+#endif
+  }
+*/
+
   void start_process() noexcept(false);
 
   int pid() const noexcept { return child_pid_; }
@@ -1409,43 +1429,21 @@ inline void Popen::execute_process() noexcept(false)
 
   this->process_handle_ = piProcInfo.hProcess;
 
-  try {
-      char err_buf[SP_MAX_ERR_BUF_SIZ] = {0,};
+  std::async(std::launch::async, [this] {
+    WaitForSingleObject(this->process_handle_, INFINITE);
 
-      int read_bytes = util::read_atmost_n(
-                                  this->error(),
-                                  err_buf,
-                                  SP_MAX_ERR_BUF_SIZ);
-      fclose(this->error());
-
-      if (read_bytes || strlen(err_buf)) {
-        // Throw whatever information we have about child failure
-        throw CalledProcessError(err_buf);
-      }
-  } catch (std::exception& exp) {
-      stream_.cleanup_fds();
-      throw;
-  }
+    CloseHandle(this->stream_.g_hChildStd_ERR_Wr);
+    CloseHandle(this->stream_.g_hChildStd_OUT_Wr);
+    CloseHandle(this->stream_.g_hChildStd_IN_Rd);
+  });
 
 /*
-  this->hExited_ =
-      std::shared_future<int>(std::async(std::launch::async, [this] {
-        WaitForSingleObject(this->hProcess_, INFINITE);
-
-        CloseHandle(this->stream_.g_hChildStd_ERR_Wr);
-        CloseHandle(this->stream_.g_hChildStd_OUT_Wr);
-        CloseHandle(this->stream_.g_hChildStd_IN_Rd);
-
-        DWORD exit_code;
-        if (FALSE == GetExitCodeProcess(this->hProcess_, &exit_code))
-          throw OSError("GetExitCodeProcess", 0);
-
-        CloseHandle(this->hProcess_);
-
-        return (int)exit_code;
-      }));
+  NOTE: In the linux version, there is a check to make sure that the process
+        has been started. Here, we do nothing because CreateProcess will throw
+        if we fail to create the process.
 */
 
+
 #else
 
   int err_rd_pipe, err_wr_pipe;
@@ -1683,7 +1681,7 @@ namespace detail {
   inline void Streams::setup_comm_channels()
   {
 #ifdef _MSC_VER
-    util::configure_pipe(this->g_hChildStd_IN_Rd, &this->g_hChildStd_IN_Wr, &this->g_hChildStd_IN_Wr);
+    util::configure_pipe(&this->g_hChildStd_IN_Rd, &this->g_hChildStd_IN_Wr, &this->g_hChildStd_IN_Wr);
     this->input(util::file_from_handle(this->g_hChildStd_IN_Wr, "w"));
     this->write_to_child_ = _fileno(this->input());
 
@@ -1935,6 +1933,12 @@ OutBuffer check_output(const std::string& arg, Args&&... args)
   return (detail::check_output_impl(arg, std::forward<Args>(args)...));
 }
 
+template <typename... Args>
+OutBuffer check_output(std::vector<std::string> plist, Args &&... args)
+{
+  return (detail::check_output_impl(plist, std::forward<Args>(args)...));
+}
+
 
 /*!
  * An easy way to pipeline easy commands.

test/test_ret_code.cc

@@ -8,7 +8,9 @@ void test_ret_code()
   std::cout << "Test::test_poll_ret_code" << std::endl;
   auto p = sp::Popen({"/usr/bin/false"});
   while (p.poll() == -1) {
+#ifndef _MSC_VER
     usleep(1000 * 100);
+#endif
   }
   assert (p.retcode() == 1);
 }

test/test_subprocess.cc

@@ -5,7 +5,11 @@ using namespace subprocess;
 
 void test_exename()
 {
+#ifdef _MSC_VER
+  auto ret = call({"--version"}, executable{"cmake"}, shell{false});
+#else
   auto ret = call({"-l"}, executable{"ls"}, shell{false});
+#endif
   std::cout << ret << std::endl;
 }
 
@@ -35,33 +39,41 @@ void test_easy_piping()
 
 void test_shell()
 {
-  auto obuf = check_output({"ls", "-l"}, shell{false});
+#ifdef _MSC_VER
+  auto obuf = check_output({"cmake", "--version"}, shell{false});
+#else
+  auto obuf = check_output({"ls", "-l"}, shell{false});  
+#endif
   std::cout << obuf.buf.data() << std::endl;
 }
 
 void test_sleep()
 {
   auto p = Popen({"sleep", "30"}, shell{true});
 
-  while (p.poll() == -1) {
+  while (p.poll() == -1)
+  {
     std::cout << "Waiting..." << std::endl;
+#ifdef _MSC_VER
+#else
     sleep(1);
+#endif
   }
 
   std::cout << "Sleep ended: ret code = " << p.retcode() << std::endl;
 }
 
 void test_read_all()
 {
-  Popen p = Popen({"echo","12345678"}, output{PIPE});
-  
+  Popen p = Popen({"echo", "12345678"}, output{PIPE});
+
   std::vector<char> buf(6);
   int rbytes = util::read_all(p.output(), buf);
 
   std::string out(buf.begin(), buf.end());
 
   assert(out == "12345678\n" && rbytes == 9); // echo puts a new line at the end of output
-  std::cout<<"read_all() succeeded"<<std::endl;
+  std::cout << "read_all() succeeded" << std::endl;
 }
 
 void test_simple_cmd()