Implements comp utility.

+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2003 Free Software Foundation, Inc.
+
+   GNU Mailutils is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   GNU Mailutils is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with GNU Mailutils; if not, write to the Free Software
+   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */
+
+/* MH comp command */
+
+#include <mh.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+const char *argp_program_version = "comp (" PACKAGE_STRING ")";
+static char doc[] = "GNU MH comp";
+static char args_doc[] = "[msg]";
+
+#define ARG_NOEDIT      1
+#define ARG_WHATNOWPROC 2
+#define ARG_NOWHATNOWPROC 3
+#define ARG_NODRAFTFOLDER 4
+#define ARG_FILE 5
+
+/* GNU options */
+static struct argp_option options[] = {
+  {"build", 'b', 0, 0,
+   N_("Build the draft and quit immediately.")},
+  {"draftfolder", 'd', N_("FOLDER"), 0,
+   N_("Specify the folder for message drafts")},
+  {"nodraftfolder", ARG_NODRAFTFOLDER, 0, 0,
+   N_("Undo the effect of the last --draftfolder option")},
+  {"draftmessage" , 'm', N_("MSG"), 0,
+   N_("Invoke the draftmessage facility")},
+  {"folder",  'f', N_("FOLDER"), 0, N_("Specify folder to operate upon")},
+  {"file",    ARG_FILE, N_("FILE"), 0, N_("Use FILE as the message draft")},
+  {"editor",  'e', N_("PROG"), 0, N_("Set the editor program to use")},
+  {"noedit", ARG_NOEDIT, 0, 0, N_("Suppress the initial edit")},
+  {"form",   'F', N_("FILE"), 0, N_("Read format from given file")},
+  {"whatnowproc", ARG_WHATNOWPROC, N_("PROG"), 0,
+   N_("Set the replacement for whatnow program")},
+  {"use", 'u', N_("BOOL"), OPTION_ARG_OPTIONAL, N_("Use draft file preserved after the last session") },
+  { N_("\nUse -help switch to obtain the list of traditional MH options. "), 0, 0, OPTION_DOC, "" },
+  { 0 }
+};
+
+/* Traditional MH options */
+struct mh_option mh_option[] = {
+  {"build", 1, NULL, },
+  {"file", 2,  NULL, MH_OPT_ARG, "draftfile"},
+  {"form", 2,  NULL, MH_OPT_ARG, "formatfile"},
+  {"draftfolder", 6, NULL, MH_OPT_ARG, "folder"},
+  {"nodraftfolder", 3, NULL },
+  {"draftmessage", 6, NULL },
+  {"editor", 1, NULL, MH_OPT_ARG, "program"},
+  {"noedit", 3, NULL, },
+  {"whatnowproc", 2, NULL, MH_OPT_ARG, "program"},
+  {"nowhatnowproc", 3, NULL },
+  { 0 }
+};
+
+static char *format_str =
+"To:\n"
+"cc:\n"
+"Subject:\n"
+"--------\n";
+
+struct mh_whatnow_env wh_env = { 0 };
+const char *formfile;
+static int initial_edit = 1;
+static int build_only = 0; /* --build flag */
+static int query_mode = 0; /* --query flag */
+static int use_draft = 0;  /* --use flag */
+
+static int
+opt_handler (int key, char *arg, void *unused)
+{
+  char *s;
+  
+  switch (key)
+    {
+    case 'b':
+    case ARG_NOWHATNOWPROC:
+      build_only = 1;
+      break;
+      
+    case 'd':
+      wh_env.draftfolder = arg;
+      break;
+      
+    case 'e':
+      wh_env.editor = arg;
+      break;
+      
+    case '+':
+    case 'f': 
+      current_folder = arg;
+      break;
+
+    case 'F':
+      formfile = mh_expand_name (MHLIBDIR, arg, 0);
+      break;
+
+    case 'm':
+      wh_env.draftmessage = arg;
+      break;
+
+    case 'u':
+      use_draft = is_true (arg);
+      break;
+
+    case ARG_FILE:
+      wh_env.draftfile = mh_expand_name (NULL, arg, 0);
+      break;
+	
+    case ARG_NODRAFTFOLDER:
+      wh_env.draftfolder = NULL;
+      break;
+
+    case ARG_NOEDIT:
+      initial_edit = 0;
+      break;
+      
+    case ARG_WHATNOWPROC:
+      mh_error (_("option is not yet implemented"));
+      exit (1);
+      
+    default:
+      return 1;
+    }
+  return 0;
+}
+
+int 
+check_draft_disposition (struct mh_whatnow_env *wh)
+{
+  struct stat st;
+  int disp = DISP_REPLACE;
+
+  /* First check if the draft exists */
+  if (stat (wh->draftfile, &st) == 0)
+    {
+      if (use_draft)
+	disp = DISP_USE;
+      else
+	{
+	  printf (_("Draft \"%s\" exists (%lu bytes).\n"),
+		  wh->draftfile, (unsigned long) st.st_size);
+	  disp = mh_disposition (wh->draftfile);
+	}
+    }
+
+  return disp;
+}
+  
+int
+copy_message (mailbox_t mbox, size_t n, const char *file)
+{
+  message_t msg;
+  stream_t in;
+  stream_t out;
+  int rc;
+  size_t size;
+  char *buffer;
+  size_t bufsize, rdsize;
+  
+  mailbox_get_message (mbox, n, &msg);
+  message_size (msg, &size);
+
+  for (bufsize = size; bufsize > 0 && (buffer = malloc (bufsize)) == 0;
+       bufsize /= 2)
+    ;
+
+  if (!bufsize)
+    mh_err_memory (1);
+
+  message_get_stream (msg, &in);
+  
+  if ((rc = file_stream_create (&out,
+				file, MU_STREAM_RDWR|MU_STREAM_CREAT)) != 0
+      || (rc = stream_open (out)))
+    {
+      mh_error (_("cannot open output file \"%s\": %s"),
+		file, mu_errstring (rc));
+      free (buffer);
+      return 1;
+    }
+
+  while (size > 0
+	 && (rc = stream_sequential_read (in, buffer, bufsize, &rdsize)) == 0
+	 && rdsize > 0)
+    {
+      if ((rc = stream_sequential_write (out, buffer, rdsize)) != 0)
+	{
+	  mh_error (_("error writing to \"%s\": %s"),
+		    file, mu_errstring (rc));
+	  break;
+	}
+      size -= rdsize;
+    }
+
+  stream_close (out);
+  stream_destroy (&out, stream_get_owner (out));
+  
+  return rc;
+}
+
+int
+main (int argc, char **argv)
+{
+  int index;
+  
+  /* Native Language Support */
+  mu_init_nls ();
+
+  mh_argp_parse (argc, argv, options, mh_option, args_doc, doc,
+		 opt_handler, NULL, &index);
+
+  if (!wh_env.draftfolder)
+    wh_env.draftfolder = mh_global_profile_get ("Draft-Folder",
+						mu_path_folder_dir);
+
+  wh_env.file = mh_expand_name (wh_env.draftfolder, "comp", 0);
+  if (!wh_env.draftfile)
+    wh_env.draftfile = mh_expand_name (wh_env.draftfolder, "draft", 0);
+
+  switch (check_draft_disposition (&wh_env))
+    {
+    case DISP_QUIT:
+      exit (0);
+
+    case DISP_USE:
+      unlink (wh_env.file);
+      rename (wh_env.draftfile, wh_env.file);
+      break;
+	  
+    case DISP_REPLACE:
+      unlink (wh_env.draftfile);
+  
+      if (index < argc)
+	{
+	  static mh_msgset_t msgset;
+	  static mailbox_t mbox;
+	  
+	  mbox = mh_open_folder (current_folder, 0);
+	  mh_msgset_parse (mbox, &msgset, argc - index, argv + index, "cur");
+	  if (msgset.count != 1)
+	    {
+	      mh_error (_("only one message at a time!"));
+	      return 1;
+	    }
+	  copy_message (mbox, msgset.list[0], wh_env.file);
+	}
+      else if (formfile)
+	{
+	  if (mh_file_copy (formfile, wh_env.file) == 0)
+	    exit (1);
+	}
+      else
+	{
+	  int rc;
+	  stream_t stream;
+	  
+	  if ((rc = file_stream_create (&stream,
+					wh_env.file,
+					MU_STREAM_WRITE|MU_STREAM_CREAT)) != 0
+	      || (rc = stream_open (stream)))
+	    {
+	      mh_error (_("cannot open output file \"%s\": %s"),
+			wh_env.file, mu_errstring (rc));
+	      exit (1);
+	    }
+	  
+	  rc = stream_sequential_write (stream, 
+					format_str, strlen (format_str));
+	  stream_close (stream);
+	  stream_destroy (&stream, stream_get_owner (stream));
+
+	  if (rc)
+	    {
+	      mh_error (_("error writing to \"%s\": %s"),
+			wh_env.file, mu_errstring (rc));
+	      exit (1);
+	    }
+	}
+    }
+  
+  /* Exit immediately if --build is given */
+  if (build_only)
+    return 0;
+
+  return mh_whatnow (&wh_env, initial_edit);
+}