Util: inherited 'execute' from Taskwarrior.

src/CMakeLists.txt

@@ -11,7 +11,8 @@ set (tasksh_SRCS diag.cpp
                  Path.cpp Path.h
                  File.cpp File.h
                  Directory.cpp Directory.h
-                 text.cpp  text.h)
+                 text.cpp text.h
+                 util.cpp util.h)
 
 add_executable (tasksh_executable main.cpp ${tasksh_SRCS})
 target_link_libraries (tasksh_executable ${TASKSH_LIBRARIES})

src/util.cpp

@@ -0,0 +1,185 @@
+////////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2006 - 2015, Paul Beckingham, Federico Hernandez.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// http://www.opensource.org/licenses/mit-license.php
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#include <cmake.h>
+#include <vector>
+#include <string>
+#include <unistd.h>
+#include <sys/select.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <errno.h>
+#include <util.h>
+
+////////////////////////////////////////////////////////////////////////////////
+// Run a binary with args, capturing output.
+int execute (
+  const std::string& executable,
+  const std::vector <std::string>& args,
+  const std::string& input,
+  std::string& output)
+{
+  pid_t pid;
+  int pin[2], pout[2];
+  fd_set rfds, wfds;
+  struct timeval tv;
+  int select_retval, read_retval, write_retval;
+  char buf[16384];
+  unsigned int written;
+  const char* input_cstr = input.c_str ();
+
+  if (signal (SIGPIPE, SIG_IGN) == SIG_ERR) // Handled locally with EPIPE.
+    throw std::string (std::strerror (errno));
+
+  if (pipe (pin) == -1)
+    throw std::string (std::strerror (errno));
+
+  if (pipe (pout) == -1)
+    throw std::string (std::strerror (errno));
+
+  if ((pid = fork ()) == -1)
+    throw std::string (std::strerror (errno));
+
+  if (pid == 0)
+  {
+    // This is only reached in the child
+    close (pin[1]);   // Close the write end of the input pipe.
+    close (pout[0]);  // Close the read end of the output pipe.
+
+    // Parent writes to pin[1]. Set read end pin[0] as STDIN for child.
+    if (dup2 (pin[0], STDIN_FILENO) == -1)
+      throw std::string (std::strerror (errno));
+    close (pin[0]);
+
+    // Parent reads from pout[0]. Set write end pout[1] as STDOUT for child.
+    if (dup2 (pout[1], STDOUT_FILENO) == -1)
+      throw std::string (std::strerror (errno));
+    close (pout[1]);
+
+    // Add executable as argv[0] and NULL-terminate the array for execvp().
+    char** argv = new char* [args.size () + 2];
+    argv[0] = (char*) executable.c_str ();
+    for (unsigned int i = 0; i < args.size (); ++i)
+      argv[i+1] = (char*) args[i].c_str ();
+
+    argv[args.size () + 1] = NULL;
+    _exit (execvp (executable.c_str (), argv));
+  }
+
+  // This is only reached in the parent
+  close (pin[0]);   // Close the read end of the input pipe.
+  close (pout[1]);  // Close the write end of the output pipe.
+
+  if (input.size () == 0)
+  {
+    // Nothing to send to the child, close the pipe early.
+    close (pin[1]);
+  }
+
+  read_retval = -1;
+  written = 0;
+  while (read_retval != 0 || input.size () != written)
+  {
+    FD_ZERO (&rfds);
+    if (read_retval != 0)
+      FD_SET (pout[0], &rfds);
+
+    FD_ZERO (&wfds);
+    if (input.size () != written)
+      FD_SET (pin[1], &wfds);
+
+    // On Linux, tv may be overwritten by select().  Reset it each time.
+    // NOTE: Timeout chosen arbitrarily - we don't time out execute() calls.
+    // select() is run over and over again unless the child exits or closes
+    // its pipes.
+    tv.tv_sec = 5;
+    tv.tv_usec = 0;
+
+    select_retval = select (std::max (pout[0], pin[1]) + 1, &rfds, &wfds, NULL, &tv);
+
+    if (select_retval == -1)
+      throw std::string (std::strerror (errno));
+
+    // Write data to child's STDIN
+    if (FD_ISSET (pin[1], &wfds))
+    {
+      write_retval = write (pin[1], input_cstr + written, input.size () - written);
+      if (write_retval == -1)
+      {
+        if (errno == EPIPE)
+        {
+          // Child died (or closed the pipe) before reading all input.
+          // We don't really care; pretend we wrote it all.
+          write_retval = input.size () - written;
+        }
+        else
+        {
+          throw std::string (std::strerror (errno));
+        }
+      }
+      written += write_retval;
+
+      if (written == input.size ())
+      {
+        // Let the child know that no more input is coming by closing the pipe.
+        close (pin[1]);
+      }
+    }
+
+    // Read data from child's STDOUT
+    if (FD_ISSET (pout[0], &rfds))
+    {
+      read_retval = read (pout[0], &buf, sizeof (buf) - 1);
+      if (read_retval == -1)
+        throw std::string (std::strerror (errno));
+
+      buf[read_retval] = '\0';
+      output += buf;
+    }
+  }
+
+  close (pout[0]);  // Close the read end of the output pipe.
+
+  int status = -1;
+  if (wait (&status) == -1)
+    throw std::string (std::strerror (errno));
+
+  if (WIFEXITED (status))
+  {
+    status = WEXITSTATUS (status);
+  }
+  else
+  {
+    throw std::string ("Error: Could not get exit status!");
+  }
+
+  if (signal (SIGPIPE, SIG_DFL) == SIG_ERR)  // We're done, return to default.
+    throw std::string (std::strerror (errno));
+
+  return status;
+}
+
+////////////////////////////////////////////////////////////////////////////////

src/util.h

@@ -0,0 +1,34 @@
+////////////////////////////////////////////////////////////////////////////////
+//
+// Copyright 2006 - 2015, Paul Beckingham, Federico Hernandez.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+//
+// http://www.opensource.org/licenses/mit-license.php
+//
+////////////////////////////////////////////////////////////////////////////////
+
+#ifndef INCLUDED_UTIL
+#define INCLUDED_UTIL
+
+// util.cpp
+int execute (const std::string&, const std::vector <std::string>&, const std::string&, std::string&);
+
+#endif
+////////////////////////////////////////////////////////////////////////////////