Argument parsing for command lines, includes conversion from scp to curl

Parser.m

- (char **) makeargs:(NSMutableArray*) listArgv argc:(int*) argc
{
  // Assumes the command line has been separated into arguments, parse the arguments if needed
  // does some conversions (~ --> home directory, for example, plus environment variables)
  // Most of the heavy parsing is done in ios_system.m (check if command is a file, etc)
  // If the command is "scp" or "sftp", do not replace "~" on remote file locations, but
  // edit the arguments (we simulate scp and sftp by calling "curl scp://remotefile")
  if ([listArgv count] == 0) { *argc = 0; return NULL; }
  NSString* cmd = [listArgv objectAtIndex:0];
  // Re-concatenate arguments with quotes (' and ")
  for (unsigned i = 0; i < [listArgv count]; i++) {
    NSString *argument = [listArgv objectAtIndex:i];
    if ([argument hasPrefix:@"'"] && !([argument hasSuffix:@"'"])) {
      do {
        // add a space
        [listArgv replaceObjectAtIndex:i withObject:[[listArgv objectAtIndex:i] stringByAppendingString:@" "]];
        // add all arguments that are part of the argument:
        [listArgv replaceObjectAtIndex:i withObject:[[listArgv objectAtIndex:i] stringByAppendingString:[listArgv objectAtIndex:(i+1)]]];
        [listArgv removeObjectAtIndex:(i+1)];
      } while (![[listArgv objectAtIndex:(i+1)] hasSuffix:@"'"]);
      // including the last one
      [listArgv replaceObjectAtIndex:i withObject:[[listArgv objectAtIndex:i] stringByAppendingString:@" "]];
      [listArgv replaceObjectAtIndex:i withObject:[[listArgv objectAtIndex:i] stringByAppendingString:[listArgv objectAtIndex:(i+1)]]];
      [listArgv removeObjectAtIndex:(i+1)];
      argument = [listArgv objectAtIndex:i];
      argument = [argument stringByReplacingOccurrencesOfString:@"'" withString:@""];
      [listArgv replaceObjectAtIndex:i withObject:argument];
    }
    // TODO: "
  }
  *argc = [listArgv count];
  char** argv = (char **)malloc((*argc + 1) * sizeof(char*));
  NSString *fileName = NULL;
  int mustAddMinusTPosition = -1;
  // 1) convert command line to argc / argv
  // 1a) split into elements
  for (unsigned i = 0; i < [listArgv count]; i++)
  {
    // Operations on individual arguments
    NSString *argument = [listArgv objectAtIndex:i];
    // 1b) expand environment variables, + "~" (not wildcards ? and *)
    while ([argument containsString:@"$"]) {
      // It has environment variables inside. Work on them one by one.
      // position of first "$" sign:
      NSRange r1 = [argument rangeOfString:@"$"];
      // position of first "/" after this $ sign:
      NSRange r2 = [argument rangeOfString:@"/" options:NULL range:NSMakeRange(r1.location + r1.length, [argument length] - r1.location - r1.length)];
      // position of first ":" after this $ sign:
      NSRange r3 = [argument rangeOfString:@":" options:NULL range:NSMakeRange(r1.location + r1.length, [argument length] - r1.location - r1.length)];
      if ((r2.location == NSNotFound) && (r3.location == NSNotFound)) r2.location = [argument length];
      else if ((r2.location == NSNotFound) || (r3.location < r2.location)) r2.location = r3.location;

      NSRange  rSub = NSMakeRange(r1.location + r1.length, r2.location - r1.location - r1.length);
      NSString *variable_string = [argument substringWithRange:rSub];
      const char* variable = getenv([variable_string UTF8String]);
      if (variable) {
        // Okay, so this one exists.
        NSString* replacement_string = [NSString stringWithCString:variable encoding:NSASCIIStringEncoding];
        variable_string = [[NSString stringWithCString:"$" encoding:NSASCIIStringEncoding] stringByAppendingString:variable_string];
        argument = [argument stringByReplacingOccurrencesOfString:variable_string withString:replacement_string];
      }
    }
    // Bash spec: only convert "~" if: at the beginning of argument, after a ":" or the first "="
    // ("=" scenario for export, but we use setenv, so no "=").
    // Only 1 possibility: "~" (same as $HOME)
    // If the command is scp or sftp, do not apply this on remote directories
    if (([cmd isEqualToString:@"scp"] || [cmd isEqualToString:@"sftp"]) && (i >= 1)) {
      if ([argument containsString:@":"]) {
        // remote host: [user@]host:[/][~]filepath --> scp://[user@]host/
        // if filepath relative, add ~
        NSRange r1 = [argument rangeOfString:@":"];
        NSRange  rSub = NSMakeRange(0, r1.location);
        NSString* userAndHost = [argument substringWithRange:rSub];
        rSub = NSMakeRange(r1.location + 1, [argument length] - r1.location - 1);
        NSString* fileLocation = [argument substringWithRange:rSub];
        if(![fileLocation hasPrefix:@"/"]) {
          // relative path
          if([fileLocation hasPrefix:@"~"]) {
            fileLocation = [[NSString stringWithCString:"/" encoding:NSASCIIStringEncoding]  stringByAppendingString:fileLocation];
          } else {
            fileLocation = [[NSString stringWithCString:"/~/" encoding:NSASCIIStringEncoding]  stringByAppendingString:fileLocation];
          }
          if (![fileLocation hasSuffix:@"/"]) fileName = fileLocation.lastPathComponent;
          else fileName = @"result.txt";
        }
        NSString *prefix = [cmd stringByAppendingString:[NSString stringWithCString:"://" encoding:NSASCIIStringEncoding]];
        argument = [[prefix stringByAppendingString:userAndHost] stringByAppendingString:fileLocation];
        // avoid ~ conversion:
        argv[i] = [argument UTF8String];
        continue;
      }
      if (![argument hasPrefix:@"-"]) {
        // Not beginning with "-", not containing ":", must be a local filename
        // if it's ".", replace with -O
        // if it's a directory, add name of file from previous argument at the end.
        if (!fileName) {
          // local file before remote file: upload
          mustAddMinusTPosition = i;
        } else if ([argument isEqualToString:@"."]) argument = @"-O";
        else if ([argument hasSuffix:@"/"]) argument = [argument stringByAppendingString:fileName];
        else {
          BOOL isDir;
          if ([[NSFileManager defaultManager] fileExistsAtPath:argument isDirectory:&isDir]) {
            if (isDir)
              argument = [argument stringByAppendingString:fileName];
          }
        }
      }
    }
    // Tilde conversion:
    if([argument hasPrefix:@"~"]) {
      // So it begins with "~"
      argument = [argument stringByExpandingTildeInPath];
      if ([argument hasPrefix:@"~:"]) {
        NSString* test_string = @"~";
        NSString* replacement_string = [NSString stringWithCString:(getenv("HOME")) encoding:NSASCIIStringEncoding];
        argument = [argument stringByReplacingOccurrencesOfString:test_string withString:replacement_string options:NULL range:NSMakeRange(0, 1)];
      }
    }
    // Also convert ":~something" in PATH style variables
    // We don't use these yet, but we could.
    if ([argument containsString:@":~"]) {
      // Only 1 possibility: ":~" (same as $HOME)
      if (getenv("HOME")) {
        if ([argument containsString:@":~/"]) {
          NSString* test_string = @":~/";
          NSString* replacement_string = [[NSString stringWithCString:":" encoding:NSASCIIStringEncoding] stringByAppendingString:[NSString stringWithCString:(getenv("HOME")) encoding:NSASCIIStringEncoding]];
          replacement_string = [replacement_string stringByAppendingString:[NSString stringWithCString:"/" encoding:NSASCIIStringEncoding]];
          argument = [argument stringByReplacingOccurrencesOfString:test_string withString:replacement_string];
        } else if ([argument hasSuffix:@":~"]) {
          NSString* test_string = @":~";
          NSString* replacement_string = [[NSString stringWithCString:":" encoding:NSASCIIStringEncoding] stringByAppendingString:[NSString stringWithCString:(getenv("HOME")) encoding:NSASCIIStringEncoding]];
          argument = [argument stringByReplacingOccurrencesOfString:test_string withString:replacement_string options:NULL range:NSMakeRange([argument length] - 2, 2)];
        } else if ([argument hasSuffix:@":"]) {
          NSString* test_string = @":";
          NSString* replacement_string = [[NSString stringWithCString:":" encoding:NSASCIIStringEncoding] stringByAppendingString:[NSString stringWithCString:(getenv("HOME")) encoding:NSASCIIStringEncoding]];
          argument = [argument stringByReplacingOccurrencesOfString:test_string withString:replacement_string options:NULL range:NSMakeRange([argument length] - 2, 2)];
        }
      }
    }
    if (([cmd isEqualToString:@"scp"] || [cmd isEqualToString:@"sftp"]) && (i == 0))
      argv[i] = [@"curl" UTF8String];
    else
      argv[i] = [argument UTF8String];
  }
  if (mustAddMinusTPosition > 0) {
    // For scp uploads
    // Need to add parameter "-T" before parameter number i.
    *argc += 1;
    argv = (char **)realloc(argv, (*argc + 1) * sizeof(char*));
    for (int i = *argc; i > mustAddMinusTPosition; i--)
      argv[i - 1] = strdup(argv[i - 2]);
    argv[mustAddMinusTPosition] = [@"-T" UTF8String];
  }
  
  argv[*argc] = NULL;
  return argv;
}