--- /dev/null
+#include "Process.hpp"
+
+#ifdef __WIN32
+# error "TODO: windows implementation of Process"
+#else
+# include <cstdio>
+# include <fcntl.h>
+# include <unistd.h>
+# include <sys/wait.h>
+#endif
+
+#include <stdexcept>
+
+using namespace std;
+
+
+namespace blank {
+
+struct Process::Impl {
+
+ Impl(
+ const string &path_in,
+ const vector<string> &args,
+ const vector<string> &env);
+ ~Impl();
+
+ size_t WriteIn(const void *buffer, size_t max_len);
+ size_t ReadOut(void *buffer, size_t max_len);
+ size_t ReadErr(void *buffer, size_t max_len);
+
+ int Join();
+
+#ifdef __WIN32
+ PROCESS_INFORMATION pi;
+ HANDLE fd_in[2];
+ HANDLE fd_out[2];
+ HANDLE fd_err[2];
+#else
+ int pid;
+ int fd_in[2];
+ int fd_out[2];
+ int fd_err[2];
+#endif
+
+};
+
+
+Process::Process(
+ const string &path,
+ const vector<string> &args,
+ const vector<string> &env)
+: impl(new Impl(path, args, env))
+, joined(false)
+, status(0) {
+
+}
+
+Process::~Process() {
+ Join();
+}
+
+
+size_t Process::WriteIn(const void *buffer, size_t max_len) {
+ return impl->WriteIn(buffer, max_len);
+}
+
+size_t Process::ReadOut(void *buffer, size_t max_len) {
+ return impl->ReadOut(buffer, max_len);
+}
+
+size_t Process::ReadErr(void *buffer, size_t max_len) {
+ return impl->ReadErr(buffer, max_len);
+}
+
+int Process::Join() {
+ if (joined) {
+ return status;
+ } else {
+ status = impl->Join();
+ joined = true;
+ return status;
+ }
+}
+
+
+Process::Impl::Impl(
+ const string &path_in,
+ const vector<string> &args,
+ const vector<string> &env
+) {
+ const char *path = path_in.c_str();
+ char *envp[env.size() + 1];
+ for (size_t i = 0; i < env.size(); ++i) {
+ envp[i] = const_cast<char *>(env[i].c_str());
+ }
+ envp[env.size()] = nullptr;
+#ifdef __WIN32
+ string cmdline;
+ for (const auto &arg : args) {
+ cmdline += '"';
+ cmdline += arg;
+ cmdline += '"';
+ }
+
+ SECURITY_ATTRIBUTES sa;
+ sa.nLength = sizeof(SECURITY_ATTRIBUTES);
+ sa.bInheritHandle = true;
+ sa.lpSecurityDescriptor = nullptr;
+ if (!CreatePipe(&fd_in[0], &fd_in[1], &sa, 0)) {
+ throw runtime_error("failed to open pipe for child process' stdin");
+ }
+ if (!SetHandleInformation(fd_in[1], HANDLE_FLAG_INHERIT, 0)) {
+ throw runtime_error("failed to stop child process from inheriting stdin write handle");
+ }
+ if (!CreatePipe(&fd_out[0], &fd_out[1], &sa, 0)) {
+ throw runtime_error("failed to open pipe for child process' stdout");
+ }
+ if (!SetHandleInformation(fd_out[0], HANDLE_FLAG_INHERIT, 0)) {
+ throw runtime_error("failed to stop child process from inheriting stdout read handle");
+ }
+ if (!CreatePipe(&fd_err[0], &fd_err[1], &sa, 0)) {
+ throw runtime_error("failed to open pipe for child process' stderr");
+ }
+ if (!SetHandleInformation(fd_err[0], HANDLE_FLAG_INHERIT, 0)) {
+ throw runtime_error("failed to stop child process from inheriting stderr read handle");
+ }
+
+ STARTUPINFO si;
+ ZeroMemory(&si, sizeof(STARTUPINFO));
+ si.cb = sizeof(STARTUPINFO);
+ si.hStdError = fd_err[1];
+ si.hStdOutput = fd_out[1];
+ si.hStdInput = fd_in[0];
+ si.dwFlags |= STARTF_USESTDHANDLES;
+ ZeroMemory(&pi, sizeof(PROCESS_INFORMATION));
+
+ if (!CreateProcess(
+ path,
+ cmdline.c_str(),
+ nullptr,
+ nullptr,
+ true,
+ 0,
+ envp,
+ nullptr,
+ &si,
+ &pi
+ )) {
+ throw runtime_error("CreateProcess");
+ }
+#else
+ char *argv[args.size() + 1];
+ for (size_t i = 0; i < args.size(); ++i) {
+ // I was promised exec won't modify my characters
+ argv[i] = const_cast<char *>(args[i].c_str());
+ }
+ argv[args.size()] = nullptr;
+
+ if (pipe(fd_in) != 0) {
+ throw runtime_error("failed to open pipe for child process' stdin");
+ }
+ if (pipe(fd_out) != 0) {
+ throw runtime_error("failed to open pipe for child process' stdout");
+ }
+ if (pipe(fd_err) != 0) {
+ throw runtime_error("failed to open pipe for child process' stderr");
+ }
+
+ pid = fork();
+ if (pid == -1) {
+ throw runtime_error("fork");
+ } else if (pid == 0) {
+
+ if (dup2(fd_in[0], STDIN_FILENO) == -1) {
+ exit(EXIT_FAILURE);
+ }
+ if (dup2(fd_out[1], STDOUT_FILENO) == -1) {
+ exit(EXIT_FAILURE);
+ }
+ if (dup2(fd_err[1], STDERR_FILENO) == -1) {
+ exit(EXIT_FAILURE);
+ }
+
+ close(fd_in[0]);
+ close(fd_in[1]);
+ close(fd_out[0]);
+ close(fd_out[1]);
+ close(fd_err[0]);
+ close(fd_err[1]);
+
+ execve(path, argv, envp);
+ // if execve returns, something bad happened
+ exit(EXIT_FAILURE);
+
+ } else {
+
+ close(fd_in[0]);
+ close(fd_out[1]);
+ close(fd_err[1]);
+
+ }
+}
+#endif
+
+Process::Impl::~Impl() {
+
+}
+
+size_t Process::Impl::WriteIn(const void *buffer, size_t max_len) {
+#ifdef __WIN32
+ DWORD written;
+ if (!WriteFile(fd_in[1], buffer, max_len, &written, nullptr)) {
+ throw runtime_error("failed to write to child process' input stream");
+ }
+ return written;
+#else
+ int written = write(fd_in[1], buffer, max_len);
+ if (written < 0) {
+ if (errno == EAGAIN) {
+ return 0;
+ } else {
+ throw runtime_error("failed to write to child process' input stream");
+ }
+ }
+ return written;
+#endif
+}
+
+size_t Process::Impl::ReadOut(void *buffer, size_t max_len) {
+#ifdef __WIN32
+ DWORD ret;
+ if (!ReadFile(fd_out[0], buffer, max_len, &ret, nullptr)) {
+ throw runtime_error("failed to read from child process' output stream");
+ }
+ return ret;
+#else
+ int ret = read(fd_out[0], buffer, max_len);
+ if (ret < 0) {
+ if (errno == EAGAIN) {
+ return 0;
+ } else {
+ throw runtime_error("failed to read from child process' output stream");
+ }
+ }
+ return ret;
+#endif
+}
+
+size_t Process::Impl::ReadErr(void *buffer, size_t max_len) {
+#ifdef __WIN32
+ DWORD ret;
+ if (!ReadFile(fd_err[0], buffer, max_len, &ret, nullptr)) {
+ throw runtime_error("failed to read from child process' error stream");
+ }
+ return ret;
+#else
+ int ret = read(fd_err[0], buffer, max_len);
+ if (ret < 0) {
+ if (errno == EAGAIN) {
+ return 0;
+ } else {
+ throw runtime_error("failed to read from child process' error stream");
+ }
+ }
+ return ret;
+#endif
+}
+
+int Process::Impl::Join() {
+#ifdef __WIN32
+ CloseHandle(fd_in[1]);
+ CloseHandle(fd_out[0]);
+ CloseHandle(fd_err[0]);
+
+ DWORD exit_code;
+ WaitForSingleObject(pi.hProcess, INFINITE);
+ GetExitCodeProcess(pi.hProcess, &exit_code);
+ CloseHandle(pi.hProcess);
+ CloseHandle(pi.hThread);
+ return exit_code;
+#else
+ // close streams before waiting on child termination
+ close(fd_in[1]);
+ close(fd_out[0]);
+ close(fd_err[0]);
+
+ while (true) {
+ int status;
+ int result = waitpid(pid, &status, 0);
+ if (result == -1) {
+ throw runtime_error("error waiting on child process");
+ }
+ if (result == pid && WIFEXITED(status)) {
+ return WEXITSTATUS(status);
+ }
+ // otherwise, child probably signalled, which we don't care
+ // about (please don't tell youth welfare), so try again
+ }
+#endif
+}
+
+}
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