# NOTE: This procedure adds a directory to the auto-path of the specified
  #       language (i.e. native Tcl or Eagle).  The directory will not be
  #       added if it is already present.  The language argument must be the
  #       literal string "eagle" or the literal string "tcl".  The directory
  #       argument is the fully qualified path for the directory to add to
  #       the auto-path.
  #
  # <public>
  proc addToAutoPath { language directory } {
    #
    # NOTE: Add the specified directory to the auto-path if not already
    #       present.
    #
    if {[string length $language] == 0 || $language eq "eagle"} then {
      if {[isEagle]} then {

  #       literal string "tcl".  The version argument must be the literal
  #       string "8.4", "8.5", or "8.6" when the language is "tcl" -OR-
  #       the literal string "1.0" when the language is "eagle".  The
  #       fileNames argument must be a well-formed list of file names to
  #       download, each one relative to the language/version-specific
  #       directory on the package file server.  The persistent argument
  #       should be non-zero if the downloaded files should be saved to
  #       permanent storage for subsequent use.
  #       permanent storage for subsequent use.  The usePgp argument
  #       should be non-zero when an OpenPGP signature file needs to be
  #       downloaded and verified for each downloaded file.  The
  #       useAutoPath argument should be non-zero to modify the auto-path
  #       to include the temporary or persistent directories containing
  #       the downloaded files.
  #
  # <public>
  proc downloadFiles { language version fileNames persistent } {
  proc downloadFiles {
          language version fileNames persistent usePgp useAutoPath } {
    variable baseUri
    variable downloadUri
    variable persistentDirectory
    variable quiet

    if {[string length $language] == 0 || $language eq "eagle"} then {
      if {$version ne "1.0"} then {
        error "unsupported Eagle version"
      }
    } elseif {$language eq "tcl"} then {
      if {$version ne "8.4" && $version ne "8.5" && $version ne "8.6"} then {
        error "unsupported Tcl version"
      }
    } else {
      error "unsupported language"
    }

    if {$persistent} then {
      set downloadRootDirectory [file join $persistentDirectory]
      set downloadRootDirectory $persistentDirectory
    } else {
      set directoryNameOnly [appendArgs \
          pkgd_ [string trim [pid] -] _ [string trim [clock seconds] -]]

      global env

      if {[info exists env(PKGD_TEMP)]} then {
        set downloadRootDirectory [file join $env(PKGD_TEMP) pkgr]
        set downloadRootDirectory $env(PKGD_TEMP)
      } elseif {[info exists env(TEMP)]} then {
        set downloadRootDirectory [file join $env(TEMP) pkgr]
        set downloadRootDirectory $env(TEMP)
      } elseif {[info exists env(TMP)]} then {
        set downloadRootDirectory [file join $env(TMP) pkgr]
        set downloadRootDirectory $env(TMP)
      } else {
        error "please set PKGD_TEMP (via environment) to temporary directory"
      }

      set downloadRootDirectory [file join \
          $downloadRootDirectory $directoryNameOnly]
    }

    set downloadDirectories [list]

    foreach fileName $fileNames {
      if {[string length $fileName] == 0 || \
          [file pathtype $fileName] ne "relative"} then {
        error [appendArgs \
            "bad file name \"" $fileName "\", not relative"]
      }

      set directoryParts [file split [file dirname $fileName]]

      if {[llength $directoryParts] == 0} then {
        error [appendArgs \
            "bad file name \"" $fileName "\", no directory parts"]
      }

      set downloadDirectory [eval file join \
          [list $downloadRootDirectory] $directoryParts]
      set downloadDirectory [file normalize [eval file join \
          [list $downloadRootDirectory] $directoryParts]]

      set downloadFileName [file join $downloadDirectory \
          [file tail $fileName]]
      set downloadFileName [file normalize [file join \
          $downloadDirectory [file tail $fileName]]]

      if {!$persistent} then {
        catch {file delete $downloadFileName}
      }

      file mkdir [file dirname $downloadFileName]

      set savedFileName $fileName
      set fileName [file join $language $version $fileName]
      set uri [subst $downloadUri]
      set fileName $savedFileName

      if {[isEagle]} then {
        writeFile $downloadFileName [interp readorgetscriptfile -- "" $uri]
        writeFile $downloadFileName \
            [interp readorgetscriptfile -- "" $uri]
      } else {
        writeFile $downloadFileName [::PackageRepository::getFileViaHttp \
            $uri 10 stdout $quiet]
        writeFile $downloadFileName \
            [::PackageRepository::getFileViaHttp $uri 10 stdout $quiet]
      }

      if {$usePgp} then {
        set downloadSignatureFileName [appendArgs $downloadFileName .asc]

        set savedFileName $fileName
        set fileName [file join \
            $language $version [appendArgs $fileName .asc]]

        set uri [subst $downloadUri]
        set fileName $savedFileName

        if {[isEagle]} then {
          writeFile $downloadSignatureFileName \
              [interp readorgetscriptfile -- "" $uri]
        } else {
          writeFile $downloadSignatureFileName \
              [::PackageRepository::getFileViaHttp $uri 10 stdout $quiet]
        }

        if {![::PackageRepository::verifyPgpSignature \
            $downloadSignatureFileName]} then {
          error [appendArgs \
              "bad PGP signature \"" $downloadSignatureFileName \"]
        }
      }

      lappend downloadDirectories [file dirname $downloadDirectory]
      lappend downloadDirectories $downloadDirectory
    }

    set downloadDirectories [lsort -unique $downloadDirectories]

    if {$useAutoPath} then {
    foreach downloadDirectory $downloadDirectories {
      addToAutoPath $language $downloadDirectory
    }
      foreach downloadDirectory $downloadDirectories {
        addToAutoPath $language $downloadDirectory
      }
    }

    return $downloadDirectories
  }

  #
  # NOTE: Setup the variables, within this namespace, used by this script.
  #
  setupDownloadVars