ENH: Further refinement of the CPack components functionality from Doug Gregor.

Details:
==========

 - New cpack_add_component, cpack_add_component_group, and
cpack_add_install_type "commands" defined as macros in the CPack
module.
 - Documentation for all of the variables and commands in the CPack module.
 - Added get_cmake_property(... COMPONENTS) to CMake to ask for the
names of all components. Used in the CPack module to automatically
build component-based installers. (Set CPACK_MONOLITHIC_INSTALL to
turn off component-based installation).
 - A group can declare its PARENT_GROUP, to build an arbitrary
hierarchy of groups.
 - New CPack command cpack_configure_downloads, which creates an
installer that downloads only the selected components on-the-fly.
Those components marked DOWNLOADED will be separate packages
downloaded on-the-fly (or, all packages can be marked as such with the
ALL option to cpack_configure_downloads). Individual components are
compressed with ZIP at installer-creation time and
downloaded/uncompressed by the installer as needed. This feature is
only available on Windows with NSIS at the moment.
 - NSIS installers can install themselves and enable the "Change"
button in Add/Remove programs, allowing users to go back and install
or remove components. This can be disabled through
cpack_configure_downloads, because it's only really useful is most of
the application's functionality is in downloaded components.
 - Bug fix: automatically install everything whose COMPONENT was not
specified (it's a hidden, required group)
 - Bug fix: fixed removal of components when re-running the NSIS
installer and unchecking components
 - Bug fix: NSIS installers now only install/remove the minimal
number of files when re-run to update the installation (or by clicking
"Change" in Add/Remove programs)

15 files changed, 1076 insertions, 51 deletions

diff --git a/Modules/CPack.cmake b/Modules/CPack.cmake
index 9782457..c8f7029 100644
--- a/Modules/CPack.cmake
+++ b/Modules/CPack.cmake
@@ -1,6 +1,370 @@
-# Default output files will be CPackConfig.cmake and CPackSourceConfig.cmake.
-# This can be overwritten with CPACK_OUTPUT_CONFIG_FILE and
-# CPACK_SOURCE_OUTPUT_CONFIG_FILE.
+# - Build binary and source package installers
+#
+# The CPack module generates binary and source installers in a variety
+# of formats using the cpack program. Inclusion of the CPack module
+# adds two new targets to the resulting makefiles, package and
+# package_source, which build the binary and source installers,
+# respectively. The generated binary installers contain everything
+# installed via CMake's INSTALL command (and the deprecated
+# INSTALL_FILES, INSTALL_PROGRAMS, and INSTALL_TARGETS commands).
+#
+# For certain kinds of binary installers (including the graphical
+# installers on Mac OS X and Windows), CPack generates installers that
+# allow users to select individual application components to
+# install. The contents of each of the components are identified by
+# the COMPONENT argument of CMake's INSTALL command. These components
+# can be annotated with user-friendly names and descriptions,
+# inter-component dependencies, etc., and grouped in various ways to
+# customize the resulting installer. See the cpack_add_* commands,
+# described below, for more information about component-specific
+# installations.
+#
+# Before including the CPack module, there are a variety of variables
+# that can be set to customize the resulting installers. The most
+# commonly-used variables are:
+#
+#   CPACK_PACKAGE_NAME - The name of the package (or application). If
+#   not specified, defaults to the project name.
+#
+#   CPACK_PACKAGE_VENDOR - The name of the package vendor (e.g.,
+#   "Kitware").
+#
+#   CPACK_PACKAGE_VERSION_MAJOR - Package major Version
+#
+#   CPACK_PACKAGE_VERSION_MINOR - Package minor Version
+#
+#   CPACK_PACKAGE_VERSION_PATCH - Package patch Version
+#
+#   CPACK_PACKAGE_DESCRIPTION_FILE - A text file used to describe the
+#   project. Used, for example, the introduction screen of a
+#   CPack-generated Windows installer to describe the project.
+#
+#   CPACK_PACKAGE_DESCRIPTION_SUMMARY - Short description of the
+#   project (only a few words).
+#
+#   CPACK_PACKAGE_FILE_NAME - The name of the package file to generate,
+#   not including the extension. For example, cmake-2.6.1-Linux-i686.
+#
+#   CPACK_PACKAGE_INSTALL_DIRECTORY - Installation directory on the
+#   target system, e.g., "CMake 2.5".
+#
+#   CPACK_RESOURCE_FILE_LICENSE - License file for the project, which
+#   will typically be displayed to the user (often with an explicit
+#   "Accept" button, for graphical installers) prior to installation.
+#
+#   CPACK_RESOURCE_FILE_README - ReadMe file for the project, which
+#   typically describes in some detail
+#
+#   CPACK_RESOURCE_FILE_WELCOME - Welcome file for the project, which
+#   welcomes users to this installer. Typically used in the graphical
+#   installers on Windows and Mac OS X.
+#
+#   CPACK_MONOLITHIC_INSTALL - Disables the component-based 
+#   installation mechanism, so that all components are always installed.
+#
+#   CPACK_GENERATOR - List of CPack generators to use. If not
+#   specified, CPack will create a set of options (e.g.,
+#   CPACK_BINARY_NSIS) allowing the user to enable/disable individual
+#   generators.
+#
+#   CPACK_OUTPUT_CONFIG_FILE - The name of the CPack configuration file
+#   for binary installers that will be generated by the CPack
+#   module. Defaults to CPackConfig.cmake.
+#
+#   CPACK_PACKAGE_EXECUTABLES - Lists each of the executables along
+#   with a text label, to be used to create Start Menu shortcuts on
+#   Windows. For example, setting this to the list ccmake;CMake will
+#   create a shortcut named "CMake" that will execute the installed
+#   executable ccmake.
+#
+#   CPACK_STRIP_FILES - List of files to be stripped. Starting with
+#   CMake 2.6.0 CPACK_STRIP_FILES will be a boolean variable which
+#   enables stripping of all files (a list of files evaluates to TRUE
+#   in CMake, so this change is compatible).
+#
+# The following CPack variables are specific to source packages, and 
+# will not affect binary packages:
+#
+#   CPACK_SOURCE_PACKAGE_FILE_NAME - The name of the source package,
+#   e.g., cmake-2.6.1
+#
+#   CPACK_SOURCE_STRIP_FILES - List of files in the source tree that
+#   will be stripped. Starting with CMake 2.6.0
+#   CPACK_SOURCE_STRIP_FILES will be a boolean variable which enables
+#   stripping of all files (a list of files evaluates to TRUE in CMake,
+#   so this change is compatible).
+#
+#   CPACK_SOURCE_GENERATOR - List of generators used for the source
+#   packages. As with CPACK_GENERATOR, if this is not specified then
+#   CPack will create a set of options (e.g., CPACK_SOURCE_ZIP)
+#   allowing users to select which packages will be generated.
+#
+#   CPACK_SOURCE_OUTPUT_CONFIG_FILE - The name of the CPack
+#   configuration file for source installers that will be generated by
+#   the CPack module. Defaults to CPackSourceConfig.cmake.
+#
+#   CPACK_SOURCE_IGNORE_FILES - Pattern of files in the source tree
+#   that won't be packaged when building a source package. This is a
+#   list of patterns, e.g., /CVS/;/\\.svn/;\\.swp$;\\.#;/#;.*~;cscope.*
+#
+# The following variables are specific to the graphical installers build
+# on Windows using the Nullsoft Installation System.
+#
+#   CPACK_PACKAGE_INSTALL_REGISTRY_KEY - Registry key used when
+#   installing this project.
+#
+#   CPACK_NSIS_MUI_ICON - The icon file (.ico) for the generated
+#   install program.
+#
+#   CPACK_NSIS_MUI_UNIICON - The icon file (.ico) for the generated
+#   uninstall program.
+#
+#   CPACK_PACKAGE_ICON - A branding image that will be displayed inside
+#   the installer.
+#
+#   CPACK_NSIS_EXTRA_INSTALL_COMMANDS - Extra NSIS commands that will
+#   be added to the install Section.
+#
+#   CPACK_NSIS_EXTRA_UNINSTALL_COMMANDS - Extra NSIS commands that will
+#   be added to the uninstall Section.
+#
+#   CPACK_NSIS_COMPRESSOR - The arguments that will be passed to the
+#   NSIS SetCompressor command.
+#
+#   CPACK_NSIS_MODIFY_PATH - If this is set to "ON", then an extra page
+#   will appear in the installer that will allow the user to choose
+#   whether the program directory should be added to the system PATH
+#   variable.
+#
+#   CPACK_NSIS_DISPLAY_NAME - The title displayed at the top of the
+#   installer.
+#
+#   CPACK_NSIS_INSTALLED_ICON_NAME - A path to the executable that
+#   contains the installer icon.
+#
+#   CPACK_NSIS_HELP_LINK - URL to a web site providing assistance in
+#   installing your application.
+#
+#   CPACK_NSIS_URL_INFO_ABOUT - URL to a web site providing more
+#   information about your application.
+#
+#   CPACK_NSIS_CONTACT - Contact information for questions and comments
+#   about the installation process.
+#
+#   CPACK_NSIS_CREATE_ICONS_EXTRA - Additional NSIS commands for
+#   creating start menu shortcuts.
+#
+#   CPACK_NSIS_DELETE_ICONS_EXTRA -Additional NSIS commands to
+#   uninstall start menu shortcuts.
+#
+# The following variables are for advanced uses of CPack:
+#
+#   CPACK_CMAKE_GENERATOR - What CMake generator should be used if the
+#   project is CMake project. Defaults to the value of CMAKE_GENERATOR;
+#   few users will want to change this setting.
+#
+#   CPACK_INSTALL_CMAKE_PROJECTS - List of four values that specify
+#   what project to install. The four values are: Build directory,
+#   Project Name, Project Component, Directory. If omitted, CPack will
+#   build an installer that installers everything.
+#
+#   CPACK_SYSTEM_NAME - System name, defaults to the value of
+#   ${CMAKE_SYSTEM_NAME}.
+#
+#   CPACK_PACKAGE_VERSION - Package full version, used internally. By
+#   default, this is built from CPACK_PACKAGE_VERSION_MAJOR,
+#   CPACK_PACKAGE_VERSION_MINOR, and CPACK_PACKAGE_VERSION_PATCH.
+#
+#   CPACK_TOPLEVEL_TAG - Directory for the installed files.
+#
+#   CPACK_INSTALL_COMMANDS - Extra commands to install components.
+#
+#   CPACK_INSTALL_DIRECTORIES - Extra directories to install.
+#
+# Component-specific installation allows users to select specific sets
+# of components to install during the install process. Installation
+# components are identified by the COMPONENT argument of CMake's
+# INSTALL commands, and should be further described by the following
+# CPack commands:
+#
+#   cpack_add_component - Describes a CPack installation component
+#   named by the COMPONENT argument to a CMake INSTALL command.
+#
+#     cpack_add_component(compname
+#                         [DISPLAY_NAME name]
+#                         [DESCRIPTION description]
+#                         [HIDDEN | REQUIRED | DISABLED ]
+#                         [GROUP group]
+#                         [DEPENDS comp1 comp2 ... ]
+#                         [INSTALL_TYPES type1 type2 ... ]
+#                         [DOWNLOADED]
+#                         [ARCHIVE_FILE filename])
+#
+#   The cmake_add_component command describes an installation
+#   component, which the user can opt to install or remove as part of
+#   the graphical installation process. compname is the name of the
+#   component, as provided to the COMPONENT argument of one or more
+#   CMake INSTALL commands.
+#
+#   DISPLAY_NAME is the displayed name of the component, used in
+#   graphical installers to display the component name. This value can
+#   be any string.
+#
+#   DESCRIPTION is an extended description of the component, used in
+#   graphical installers to give the user additional information about
+#   the component. Descriptions can span multiple lines using "\n" as
+#   the line separator. Typically, these descriptions should be no
+#   more than a few lines long.
+#
+#   HIDDEN indicates that this component will be hidden in the
+#   graphical installer, so that the user cannot directly change
+#   whether it is installed or not.
+#
+#   REQUIRED indicates that this component is required, and therefore
+#   will always be installed. It will be visible in the graphical
+#   installer, but it cannot be unselected. (Typically, required
+#   components are shown greyed out).
+#
+#   DISABLED indicates that this component should be disabled
+#   (unselected) by default. The user is free to select this component
+#   for installation, unless it is also HIDDEN.
+#
+#   DEPENDS lists the components on which this component depends. If
+#   this component is selected, then each of the components listed
+#   must also be selected. The dependency information is encoded
+#   within the installer itself, so that users cannot install
+#   inconsitent sets of components.
+#
+#   GROUP names the component group of which this component is a
+#   part. If not provided, the component will be a standalone
+#   component, not part of any component group. Component groups are
+#   described with the cpack_add_component_group command, detailed
+#   below.
+#
+#   INSTALL_TYPES lists the installation types of which this component
+#   is a part. When one of these installations types is selected, this
+#   component will automatically be selected. Installation types are
+#   described with the cpack_add_install_type command, detailed below.
+#
+#   DOWNLOADED indicates that this component should be downloaded
+#   on-the-fly by the installer, rather than packaged in with the
+#   installer itself. For more information, see the cpack_configure_downloads
+#   command.
+#
+#   ARCHIVE_FILE provides a name for the ZIP file created by CPack to
+#   be used for downloaded components. If not supplied, CPack will
+#   create ZIP file with some name based on CPACK_PACKAGE_FILE_NAME and
+#   the name of the component. See cpack_configure_downloads for more
+#   information.
+#
+#   cpack_add_component_group - Describes a group of related CPack
+#   installation components.
+#
+#     cpack_add_component_group(groupname
+#                              [DISPLAY_NAME name]
+#                              [DESCRIPTION description]
+#                              [PARENT_GROUP parent]
+#                              [EXPANDED]
+#                              [BOLD_TITLE])
+#
+#   The cpack_add_component_group describes a group of installation
+#   components, which will be placed together within the listing of
+#   options. Typically, component groups allow the user to
+#   select/deselect all of the components within a single group via a
+#   single group-level option. Use component groups to reduce the
+#   complexity of installers with many options. groupname is an
+#   arbitrary name used to identify the group in the GROUP argument of
+#   the cpack_add_component command, which is used to place a
+#   component in a group. The name of the group must not conflict with
+#   the name of any component.
+#
+#   DISPLAY_NAME is the displayed name of the component group, used in
+#   graphical installers to display the component group name. This
+#   value can be any string.
+#
+#   DESCRIPTION is an extended description of the component group,
+#   used in graphical installers to give the user additional
+#   information about the components within that group. Descriptions
+#   can span multiple lines using "\n" as the line
+#   separator. Typically, these descriptions should be no more than a
+#   few lines long.
+#
+#   PARENT_GROUP, if supplied, names the parent group of this group. 
+#   Parent groups are used to establish a hierarchy of groups, 
+#   providing an arbitrary hierarchy of groups.
+#
+#   EXPANDED indicates that, by default, the group should show up as
+#   "expanded", so that the user immediately sees all of the
+#   components within the group. Otherwise, the group will initially
+#   show up as a single entry.
+#
+#   BOLD_TITLE indicates that the group title should appear in bold,
+#   to call the user's attention to the group.
+#
+#   cpack_add_install_type - Add a new installation type containing a
+#   set of predefined component selections to the graphical installer.
+#                      
+#     cpack_add_install_type(typename
+#                            [DISPLAY_NAME name])   
+#
+#   The cpack_add_install_type command identifies a set of preselected
+#   components that represents a common use case for an
+#   application. For example, a "Developer" install type might include
+#   an application along with its header and library files, while an
+#   "End user" install type might just include the application's
+#   executable. Each component identifies itself with one or more
+#   install types via the INSTALL_TYPES argument to
+#   cpack_add_component.
+#
+#   DISPLAY_NAME is the displayed name of the install type, which will
+#   typically show up in a drop-down box within a graphical
+#   installer. This value can be any string.
+#
+#   cpack_configure_downloads - Configure CPack to download selected
+#   components on-the-fly as part of the installation process.
+#
+#     cpack_configure_downloads(site
+#                               [UPLOAD_DIRECTORY dirname]
+#                               [ALL]
+#                               [ADD_REMOVE|NO_ADD_REMOVE])
+#
+#   The cpack_configure_downloads command configures installation-time
+#   downloads of selected components. For each downloadable component,
+#   CPack will create a ZIP file containing the contents of that component,
+#   which should be uploaded to the given site. When the user selects that
+#   component for installation, the installer will download and extract
+#   the component in place. This feature is useful for creating small
+#   installers that only download the requested components, saving
+#   bandwidth. Additionally, the installers are small enough that they
+#   will be installed as part of the normal installation process, and the 
+#   "Change" button in Windows Add/Remove Programs control panel will
+#   allow one to add or remove parts of the application after the original
+#   installation. The downloaded-components functionality is currently
+#   only available with the NSIS generator on Windows. It requires the
+#   ZipDLL plug-in for NSIS, available at:
+#
+#     http://nsis.sourceforge.net/ZipDLL_plug-in
+#
+#   The site argument is a URL where the ZIP files for downloadable 
+#   components will reside, e.g., http://www.cmake.org/files/2.6.1/installer/
+#   All of the ZIP files produced by CPack should be uploaded to that location.
+#
+#   UPLOAD_DIRECTORY is the local directory where CPack will create the 
+#   various .ZIP archives for each of the components. The contents of this
+#   directory should be uploaded to a location accessible by the URL given
+#   in the site argument. If omitted, CPack will use the directory CPackUploads
+#   inside the CMake binary directory to store the generated ZIP files.
+#
+#   The ALL flag indicates that all components be downloaded. Otherwise, only 
+#   those components explicitly marked as DOWNLOADED or that have a specified 
+#   ARCHIVE_FILE will be downloaded. Additionally, the ALL option implies
+#   ADD_REMOVE (unless NO_ADD_REMOVE is specified).
+#
+#   ADD_REMOVE indicates that CPack should install a copy of the installer
+#   that can be called from Windows' Add/Remove Programs dialog (via the 
+#   "Modify" button) to change the set of installed components. NO_ADD_REMOVE
+#   turns off this behavior.
+
 
 # Pick a configuration file
 SET(cpack_input_file "${CMAKE_ROOT}/Templates/CPackConfig.cmake.in")
@@ -12,6 +376,215 @@ IF(EXISTS "${CMAKE_SOURCE_DIR}/CPackSourceConfig.cmake.in")
   SET(cpack_source_input_file "${CMAKE_SOURCE_DIR}/CPackSourceConfig.cmake.in")
 ENDIF(EXISTS "${CMAKE_SOURCE_DIR}/CPackSourceConfig.cmake.in")
 
+# Argument-parsing macro from http://www.cmake.org/Wiki/CMakeMacroParseArguments
+MACRO(cpack_parse_arguments prefix arg_names option_names)
+  SET(${prefix}_DEFAULT_ARGS)
+  FOREACH(arg_name ${arg_names})    
+    SET(${prefix}_${arg_name})
+  ENDFOREACH(arg_name)
+  FOREACH(option ${option_names})
+    SET(${prefix}_${option} FALSE)
+  ENDFOREACH(option)
+
+  SET(current_arg_name DEFAULT_ARGS)
+  SET(current_arg_list)
+  FOREACH(arg ${ARGN})            
+    SET(larg_names ${arg_names})    
+    LIST(FIND larg_names "${arg}" is_arg_name)                   
+    IF (is_arg_name GREATER -1)
+      SET(${prefix}_${current_arg_name} ${current_arg_list})
+      SET(current_arg_name ${arg})
+      SET(current_arg_list)
+    ELSE (is_arg_name GREATER -1)
+      SET(loption_names ${option_names})    
+      LIST(FIND loption_names "${arg}" is_option)            
+      IF (is_option GREATER -1)
+        SET(${prefix}_${arg} TRUE)
+      ELSE (is_option GREATER -1)
+        SET(current_arg_list ${current_arg_list} ${arg})
+      ENDIF (is_option GREATER -1)
+    ENDIF (is_arg_name GREATER -1)
+  ENDFOREACH(arg)
+  SET(${prefix}_${current_arg_name} ${current_arg_list})
+ENDMACRO(cpack_parse_arguments)
+
+# Macro that appends a SET command for the given variable name (var)
+# to the macro named strvar, but only if the variable named "var"
+# has been defined. The string will eventually be appended to a CPack
+# configuration file.
+MACRO(cpack_append_variable_set_command var strvar)
+  IF (DEFINED ${var})
+    SET(${strvar} "${${strvar}}SET(${var}")
+    FOREACH(APPENDVAL ${${var}})
+      SET(${strvar} "${${strvar}} ${APPENDVAL}")
+    ENDFOREACH(APPENDVAL)
+    SET(${strvar} "${${strvar}})\n")
+  ENDIF (DEFINED ${var})
+ENDMACRO(cpack_append_variable_set_command)
+
+# Macro that appends a SET command for the given variable name (var)
+# to the macro named strvar, but only if the variable named "var"
+# has been defined and is a string. The string will eventually be
+# appended to a CPack configuration file.
+MACRO(cpack_append_string_variable_set_command var strvar)
+  IF (DEFINED ${var})
+    LIST(LENGTH ${var} CPACK_APP_VALUE_LEN)
+    IF(${CPACK_APP_VALUE_LEN} EQUAL 1)
+      SET(${strvar} "${${strvar}}SET(${var} \"${${var}}\")\n")
+    ENDIF(${CPACK_APP_VALUE_LEN} EQUAL 1)
+  ENDIF (DEFINED ${var})
+ENDMACRO(cpack_append_string_variable_set_command)
+
+# Macro that appends a SET command for the given variable name (var)
+# to the macro named strvar, but only if the variable named "var"
+# has been set to true. The string will eventually be
+# appended to a CPack configuration file.
+MACRO(cpack_append_option_set_command var strvar)
+  IF (${var})
+    LIST(LENGTH ${var} CPACK_APP_VALUE_LEN)
+    IF(${CPACK_APP_VALUE_LEN} EQUAL 1)
+      SET(${strvar} "${${strvar}}SET(${var} TRUE)\n")
+    ENDIF(${CPACK_APP_VALUE_LEN} EQUAL 1)
+  ENDIF (${var})
+ENDMACRO(cpack_append_option_set_command)
+
+# Macro that adds a component to the CPack installer
+MACRO(cpack_add_component compname)
+  STRING(TOUPPER ${compname} CPACK_ADDCOMP_UNAME)
+  cpack_parse_arguments(CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}
+    "DISPLAY_NAME;DESCRIPTION;GROUP;DEPENDS;INSTALL_TYPES;ARCHIVE_FILE"
+    "HIDDEN;REQUIRED;DISABLED;DOWNLOADED"
+    ${ARGN}
+    )
+  
+  if (CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_DOWNLOADED)
+    SET(CPACK_ADDCOMP_STR "\n# Configuration for downloaded component \"${compname}\"\n")
+  else ()
+    SET(CPACK_ADDCOMP_STR "\n# Configuration for component \"${compname}\"\n")
+  endif ()
+
+  IF(NOT CPACK_MONOLITHIC_INSTALL)
+    # If the user didn't set CPACK_COMPONENTS_ALL explicitly, update the
+    # value of CPACK_COMPONENTS_ALL in the configuration file. This will
+    # take care of any components that have been added after the CPack
+    # moduled was included.
+    IF(NOT CPACK_COMPONENTS_ALL_SET_BY_USER)
+      GET_CMAKE_PROPERTY(CPACK_ADDCOMP_COMPONENTS COMPONENTS)
+      SET(CPACK_ADDCOMP_STR "${CPACK_ADDCOMP_STR}\nSET(CPACK_COMPONENTS_ALL")
+      FOREACH(COMP ${CPACK_ADDCOMP_COMPONENTS})
+        SET(CPACK_ADDCOMP_STR "${CPACK_ADDCOMP_STR} ${COMP}")
+      ENDFOREACH(COMP)
+      SET(CPACK_ADDCOMP_STR "${CPACK_ADDCOMP_STR})\n")
+    ENDIF(NOT CPACK_COMPONENTS_ALL_SET_BY_USER)
+  ENDIF(NOT CPACK_MONOLITHIC_INSTALL)
+
+  cpack_append_string_variable_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_DISPLAY_NAME
+    CPACK_ADDCOMP_STR)
+  cpack_append_string_variable_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_DESCRIPTION
+    CPACK_ADDCOMP_STR)
+  cpack_append_variable_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_GROUP
+    CPACK_ADDCOMP_STR)
+  cpack_append_variable_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_DEPENDS
+    CPACK_ADDCOMP_STR)
+  cpack_append_variable_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_INSTALL_TYPES
+    CPACK_ADDCOMP_STR)
+  cpack_append_string_variable_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_ARCHIVE_FILE
+    CPACK_ADDCOMP_STR)    
+  cpack_append_option_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_HIDDEN
+    CPACK_ADDCOMP_STR)
+  cpack_append_option_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_REQUIRED
+    CPACK_ADDCOMP_STR)
+  cpack_append_option_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_DISABLED
+    CPACK_ADDCOMP_STR)
+  cpack_append_option_set_command(
+    CPACK_COMPONENT_${CPACK_ADDCOMP_UNAME}_DOWNLOADED
+    CPACK_ADDCOMP_STR)
+  FILE(APPEND "${CPACK_OUTPUT_CONFIG_FILE}" "${CPACK_ADDCOMP_STR}")
+ENDMACRO(cpack_add_component)
+
+# Macro that adds a component group to the CPack installer
+MACRO(cpack_add_component_group grpname)
+  STRING(TOUPPER ${grpname} CPACK_ADDGRP_UNAME)
+  cpack_parse_arguments(CPACK_COMPONENT_GROUP_${CPACK_ADDGRP_UNAME}
+    "DISPLAY_NAME;DESCRIPTION"
+    "EXPANDED;BOLD_TITLE"
+    ${ARGN}
+    )
+
+  SET(CPACK_ADDGRP_STR "\n# Configuration for component group \"${grpname}\"\n")
+  cpack_append_string_variable_set_command(
+    CPACK_COMPONENT_GROUP_${CPACK_ADDGRP_UNAME}_DISPLAY_NAME
+    CPACK_ADDGRP_STR)
+  cpack_append_string_variable_set_command(
+    CPACK_COMPONENT_GROUP_${CPACK_ADDGRP_UNAME}_DESCRIPTION
+    CPACK_ADDGRP_STR)
+  cpack_append_option_set_command(
+    CPACK_COMPONENT_GROUP_${CPACK_ADDGRP_UNAME}_EXPANDED
+    CPACK_ADDGRP_STR)
+  cpack_append_option_set_command(
+    CPACK_COMPONENT_GROUP_${CPACK_ADDGRP_UNAME}_BOLD_TITLE
+    CPACK_ADDGRP_STR)
+  FILE(APPEND "${CPACK_OUTPUT_CONFIG_FILE}" "${CPACK_ADDGRP_STR}")
+ENDMACRO(cpack_add_component_group)
+
+# Macro that adds an installation type to the CPack installer
+MACRO(cpack_add_install_type insttype)
+  STRING(TOUPPER ${insttype} CPACK_INSTTYPE_UNAME)
+  cpack_parse_arguments(CPACK_INSTALL_TYPE_${CPACK_INSTTYPE_UNAME}
+    "DISPLAY_NAME"
+    ""
+    ${ARGN}
+    )
+
+  SET(CPACK_INSTTYPE_STR 
+    "\n# Configuration for installation type \"${insttype}\"\n")
+  SET(CPACK_INSTTYPE_STR 
+    "${CPACK_INSTTYPE_STR}LIST(APPEND CPACK_ALL_INSTALL_TYPES ${insttype})\n")
+  cpack_append_string_variable_set_command(
+    CPACK_INSTALL_TYPE_${CPACK_INSTTYPE_UNAME}_DISPLAY_NAME
+    CPACK_INSTTYPE_STR)
+  FILE(APPEND "${CPACK_OUTPUT_CONFIG_FILE}" "${CPACK_INSTTYPE_STR}")
+ENDMACRO(cpack_add_install_type)
+
+MACRO(cpack_configure_downloads site)
+  cpack_parse_arguments(CPACK_DOWNLOAD
+    "UPLOAD_DIRECTORY"
+    "ALL;ADD_REMOVE;NO_ADD_REMOVE"
+    ${ARGN}
+    )
+    
+  SET(CPACK_CONFIG_DL_STR
+    "\n# Downloaded components configuration\n")
+  SET(CPACK_UPLOAD_DIRECTORY ${CPACK_DOWNLOAD_UPLOAD_DIRECTORY})
+  SET(CPACK_DOWNLOAD_SITE ${site})
+  cpack_append_string_variable_set_command(
+    CPACK_DOWNLOAD_SITE
+    CPACK_CONFIG_DL_STR)  
+  cpack_append_string_variable_set_command(
+    CPACK_UPLOAD_DIRECTORY
+    CPACK_CONFIG_DL_STR)
+  cpack_append_option_set_command(
+    CPACK_DOWNLOAD_ALL
+    CPACK_CONFIG_DL_STR)
+  IF (${CPACK_DOWNLOAD_ALL} AND NOT ${CPACK_DOWNLOAD_NO_ADD_REMOVE})
+    SET(CPACK_DOWNLOAD_ADD_REMOVE ON)
+  ENDIF (${CPACK_DOWNLOAD_ALL} AND NOT ${CPACK_DOWNLOAD_NO_ADD_REMOVE})
+  SET(CPACK_ADD_REMOVE ${CPACK_DOWNLOAD_ADD_REMOVE})
+  cpack_append_option_set_command(
+    CPACK_ADD_REMOVE
+    CPACK_CONFIG_DL_STR)
+  FILE(APPEND "${CPACK_OUTPUT_CONFIG_FILE}" "${CPACK_CONFIG_DL_STR}")
+ENDMACRO(cpack_configure_downloads)
+
 # Macro for setting values if a user did not overwrite them
 MACRO(cpack_set_if_not_set name value)
   IF(NOT DEFINED "${name}")
@@ -197,6 +770,39 @@ cpack_set_if_not_set(CPACK_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}")
 cpack_set_if_not_set(CPACK_NSIS_INSTALLER_ICON_CODE "")
 cpack_set_if_not_set(CPACK_NSIS_INSTALLER_MUI_ICON_CODE "")
 
+IF(DEFINED CPACK_COMPONENTS_ALL)
+  IF(CPACK_MONOLITHIC_INSTALL)
+    MESSAGE("CPack warning: both CPACK_COMPONENTS_ALL and CPACK_MONOLITHIC_INSTALL have been set.\nDefaulting to a monolithic installation.")
+    SET(CPACK_COMPONENTS_ALL)
+  ELSE(CPACK_MONOLITHIC_INSTALL)
+    # The user has provided the set of components to be installed as
+    # part of a component-based installation; trust her.
+    SET(CPACK_COMPONENTS_ALL_SET_BY_USER TRUE)
+  ENDIF(CPACK_MONOLITHIC_INSTALL)
+ELSE(DEFINED CPACK_COMPONENTS_ALL)
+  # If the user has not specifically requested a monolithic installer
+  # but has specified components in various "install" commands, tell
+  # CPack about those components.
+  IF(NOT CPACK_MONOLITHIC_INSTALL)
+    GET_CMAKE_PROPERTY(CPACK_COMPONENTS_ALL COMPONENTS)
+    LIST(LENGTH CPACK_COMPONENTS_ALL CPACK_COMPONENTS_LEN)
+    IF(CPACK_COMPONENTS_LEN EQUAL 1)
+      # Only one component: this is not a component-based installation
+      # (at least, it isn't a component-based installation, but may
+      # become one later if the user uses the cpack_add_* commands).
+      SET(CPACK_COMPONENTS_ALL)
+    ENDIF(CPACK_COMPONENTS_LEN EQUAL 1)
+    SET(CPACK_COMPONENTS_LEN)
+  ENDIF(NOT CPACK_MONOLITHIC_INSTALL)
+ENDIF(DEFINED CPACK_COMPONENTS_ALL)
+
+# CMake always generates a component named "Unspecified", which is
+# used to install everything that doesn't have an explicitly-provided
+# component. Since these files should always be installed, we'll make
+# them hidden and required.
+set(CPACK_COMPONENT_UNSPECIFIED_HIDDEN TRUE)
+set(CPACK_COMPONENT_UNSPECIFIED_REQUIRED TRUE)
+
 cpack_encode_variables()
 configure_file("${cpack_input_file}" "${CPACK_OUTPUT_CONFIG_FILE}" @ONLY IMMEDIATE)
 
diff --git a/Modules/NSIS.template.in b/Modules/NSIS.template.in
index 8879a7f..96598d9 100644
--- a/Modules/NSIS.template.in
+++ b/Modules/NSIS.template.in
@@ -37,6 +37,8 @@
   ;Set compression
   SetCompressor @CPACK_NSIS_COMPRESSOR@
    
+@CPACK_NSIS_DEFINES@   
+   
   !include Sections.nsh
   
 ;--- Component support macros: ---
@@ -60,6 +62,11 @@ Var AR_RegFlags
   IntOp $R0 0 + $${VarName}
 !macroend
 
+; Sets the value of a variable
+!macro StoreVar VarName IntValue
+  IntOp $${VarName} 0 + ${IntValue}
+!macroend
+
 !macro InitSection SecName
   ;  This macro reads component installed flag from the registry and
   ;changes checked state of the section on the components page.
@@ -76,9 +83,13 @@ Var AR_RegFlags
   IntOp $AR_SecFlags $AR_SecFlags & 0xFFFE  ;Turn lowest (enabled) bit off
   IntOp $AR_SecFlags $AR_RegFlags | $AR_SecFlags      ;Change lowest bit
 
+  ; Note whether this component was installed before
+  !insertmacro StoreVar ${SecName}_was_installed $AR_RegFlags
+  IntOp $R0 $AR_RegFlags & $AR_RegFlags
+  
   ;Writing modified flags
   SectionSetFlags ${${SecName}} $AR_SecFlags
- 
+  
  "default_${SecName}:"
  !insertmacro LoadSectionSelectedIntoVar ${SecName} ${SecName}_selected
 !macroend
@@ -461,6 +472,33 @@ Function ConditionalAddToRegisty
 FunctionEnd
 
 ;--------------------------------
+
+!ifdef CPACK_USES_DOWNLOAD
+Function DownloadFile
+    IfFileExists $INSTDIR\* +2
+    CreateDirectory $INSTDIR
+    Pop $0
+
+    ; Skip if already downloaded
+    IfFileExists $INSTDIR\$0 0 +2
+    Return
+
+    StrCpy $1 "@CPACK_DOWNLOAD_SITE@"
+
+  try_again:
+    NSISdl::download "$1/$0" "$INSTDIR\$0"
+    
+    Pop $1
+    StrCmp $1 "success" success
+    StrCmp $1 "Cancelled" cancel
+    MessageBox MB_OK "Download failed: $1"
+  cancel:
+    Return
+  success:
+FunctionEnd
+!endif
+
+;--------------------------------
 ; Installation types
 @CPACK_NSIS_INSTALLATION_TYPES@
 
@@ -519,7 +557,7 @@ Section "-Core installation"
   ;list of directories here in sync with the RMDir commands below.
   SetOutPath "$INSTDIR"
   @CPACK_NSIS_FULL_INSTALL@
-
+  
   ;Store installation folder
   WriteRegStr SHCTX "Software\@CPACK_PACKAGE_VENDOR@\@CPACK_PACKAGE_INSTALL_REGISTRY_KEY@" "" $INSTDIR
   
@@ -537,7 +575,20 @@ Section "-Core installation"
   Push "UninstallString"
   Push "$INSTDIR\Uninstall.exe"
   Call ConditionalAddToRegisty
+  Push "NoRepair"
+  Push "1"
+  Call ConditionalAddToRegisty
+  
+  !ifdef CPACK_NSIS_ADD_REMOVE
+  ;Create add/remove functionality
   Push "ModifyPath"
+  Push "$INSTDIR\AddRemove.exe"
+  Call ConditionalAddToRegisty
+  !else
+  Push "NoModify"
+  Push "1"
+  Call ConditionalAddToRegisty
+  !endif
   
   ; Optional registration
   Push "DisplayIcon"
@@ -640,6 +691,23 @@ FunctionEnd
 Section -FinishComponents
   ;Removes unselected components and writes component status to registry
   !insertmacro SectionList "FinishSection"
+  
+!ifdef CPACK_NSIS_ADD_REMOVE  
+  ; Get the name of the installer executable
+  System::Call 'kernel32::GetModuleFileNameA(i 0, t .R0, i 1024) i r1'
+  StrCpy $R3 $R0
+  
+  ; Strip off the last 13 characters, to see if we have AddRemove.exe
+  StrLen $R1 $R0
+  IntOp $R1 $R0 - 13
+  StrCpy $R2 $R0 13 $R1
+  StrCmp $R2 "AddRemove.exe" addremove_installed
+  
+  ; We're not running AddRemove.exe, so install it
+  CopyFiles $R3 $INSTDIR\AddRemove.exe
+  
+  addremove_installed:
+!endif
 SectionEnd
 ;--- End of Add/Remove callback functions ---
 
@@ -674,6 +742,11 @@ Section "Uninstall"
 @CPACK_NSIS_DELETE_FILES@
 @CPACK_NSIS_DELETE_DIRECTORIES@
 
+!ifdef CPACK_NSIS_ADD_REMOVE  
+  ;Remove the add/remove program
+  Delete "$INSTDIR\AddRemove.exe"
+!endif
+
   ;Remove the uninstaller itself.
   Delete "$INSTDIR\Uninstall.exe"
   DeleteRegKey SHCTX "Software\Microsoft\Windows\CurrentVersion\Uninstall\@CPACK_PACKAGE_INSTALL_DIRECTORY@"
diff --git a/Source/CPack/cmCPackComponentGroup.h b/Source/CPack/cmCPackComponentGroup.h
index 2e1703c..d080a87 100644
--- a/Source/CPack/cmCPackComponentGroup.h
+++ b/Source/CPack/cmCPackComponentGroup.h
@@ -70,12 +70,20 @@ public:
   /// Whether this component defaults to "disabled".
   bool IsDisabledByDefault : 1;
 
+  /// Whether this component should be downloaded on-the-fly. If false,
+  /// the component will be a part of the installation package.
+  bool IsDownloaded : 1;
+
   /// A description of this component.
   std::string Description;
 
   /// The installation types that this component is a part of.
   std::vector<cmCPackInstallationType *> InstallationTypes;
 
+  /// If IsDownloaded is true, the name of the archive file that
+  /// contains the files that are part of this component.
+  std::string ArchiveFile;
+
   /// The components that this component depends on.
   std::vector<cmCPackComponent *> Dependencies;
 
@@ -95,6 +103,8 @@ public:
 class cmCPackComponentGroup
 {
 public:
+ cmCPackComponentGroup() : ParentGroup(0) { }
+
   /// The name of the group (used to reference the group).
   std::string Name;
 
@@ -112,6 +122,12 @@ public:
 
   /// The components within this group.
   std::vector<cmCPackComponent*> Components;
+
+  /// The parent group of this component group (if any).
+  cmCPackComponentGroup *ParentGroup;
+
+  /// The subgroups of this group.
+  std::vector<cmCPackComponentGroup*> Subgroups;
 };
 
 #endif
diff --git a/Source/CPack/cmCPackGenerator.cxx b/Source/CPack/cmCPackGenerator.cxx
index f786f80..5090606 100644
--- a/Source/CPack/cmCPackGenerator.cxx
+++ b/Source/CPack/cmCPackGenerator.cxx
@@ -653,6 +653,14 @@ int cmCPackGenerator::InstallProjectViaInstallCMakeProjects(
             }
           mf->AddDefinition("CMAKE_INSTALL_PREFIX", dir.c_str());
 
+          if ( !cmsys::SystemTools::MakeDirectory(dir.c_str()))
+            {
+            cmCPackLogger(cmCPackLog::LOG_ERROR,
+                          "Problem creating temporary directory: " 
+                          << dir << std::endl);
+            return 0;
+            }
+
           cmCPackLogger(cmCPackLog::LOG_DEBUG,
                         "- Using DESTDIR + CPACK_INSTALL_PREFIX... (mf->AddDefinition)"
                         << std::endl);
@@ -664,6 +672,14 @@ int cmCPackGenerator::InstallProjectViaInstallCMakeProjects(
           {
           mf->AddDefinition("CMAKE_INSTALL_PREFIX", tempInstallDirectory.c_str());
 
+          if ( !cmsys::SystemTools::MakeDirectory(tempInstallDirectory.c_str()))
+            {
+            cmCPackLogger(cmCPackLog::LOG_ERROR,
+                          "Problem creating temporary directory: " 
+                          << tempInstallDirectory << std::endl);
+            return 0;
+            }
+
           cmCPackLogger(cmCPackLog::LOG_DEBUG,
                         "- Using non-DESTDIR install... (mf->AddDefinition)" << std::endl);
           cmCPackLogger(cmCPackLog::LOG_DEBUG,
@@ -1255,6 +1271,16 @@ cmCPackGenerator::GetComponent(const char *projectName, const char *name)
       = this->IsSet((macroPrefix + "_REQUIRED").c_str());
     component->IsDisabledByDefault
       = this->IsSet((macroPrefix + "_DISABLED").c_str());
+    component->IsDownloaded
+      = this->IsSet((macroPrefix + "_DOWNLOADED").c_str())
+        || cmSystemTools::IsOn(this->GetOption("CPACK_DOWNLOAD_ALL"));
+
+    const char* archiveFile = this->GetOption((macroPrefix + "_ARCHIVE_FILE").c_str());
+    if (archiveFile && *archiveFile)
+      {
+      component->ArchiveFile = archiveFile;
+      }
+
     const char* groupName = this->GetOption((macroPrefix + "_GROUP").c_str());
     if (groupName && *groupName) 
       {
@@ -1344,6 +1370,17 @@ cmCPackGenerator::GetComponentGroup(const char *projectName, const char *name)
       = this->IsSet((macroPrefix + "_BOLD_TITLE").c_str());
     group->IsExpandedByDefault
       = this->IsSet((macroPrefix + "_EXPANDED").c_str());
+    const char* parentGroupName 
+      = this->GetOption((macroPrefix + "_PARENT_GROUP").c_str());
+    if (parentGroupName && *parentGroupName)
+      {
+      group->ParentGroup = GetComponentGroup(projectName, parentGroupName);
+      group->ParentGroup->Subgroups.push_back(group);
+      }
+    else
+      {
+      group->ParentGroup = 0;
+      }
     }
   return group;
 }
diff --git a/Source/CPack/cmCPackNSISGenerator.cxx b/Source/CPack/cmCPackNSISGenerator.cxx
index cd4ffb8..7be5cb2 100644
--- a/Source/CPack/cmCPackNSISGenerator.cxx
+++ b/Source/CPack/cmCPackNSISGenerator.cxx
@@ -173,6 +173,9 @@ int cmCPackNSISGenerator::CompressFiles(const char* outFileName,
     std::string componentDescriptions;
     std::string groupDescriptions;
     std::string installTypesCode;
+    std::string defines;
+    cmOStringStream macrosOut;
+    bool anyDownloadedComponents = false;
 
     // Create installation types. The order is significant, so we first fill
     // in a vector based on the indices, and print them in that order.
@@ -201,7 +204,11 @@ int cmCPackNSISGenerator::CompressFiles(const char* outFileName,
          groupIt != this->ComponentGroups.end();
          ++groupIt)
       {
-      componentCode += this->CreateComponentGroupDescription(&groupIt->second);
+      if (groupIt->second.ParentGroup == 0)
+        {
+        componentCode += 
+          this->CreateComponentGroupDescription(&groupIt->second, macrosOut);
+        }
 
       // Add the group description, if any.
       if (!groupIt->second.Description.empty())
@@ -218,9 +225,19 @@ int cmCPackNSISGenerator::CompressFiles(const char* outFileName,
          compIt != this->Components.end();
          ++compIt)
       {
+      if (compIt->second.Files.empty())
+        {
+        // NSIS cannot cope with components that have no files.
+        continue;
+        }
+
+      anyDownloadedComponents =
+        anyDownloadedComponents || compIt->second.IsDownloaded;
+
       if (!compIt->second.Group)
         {
-        componentCode += this->CreateComponentDescription(&compIt->second);
+        componentCode 
+          += this->CreateComponentDescription(&compIt->second, macrosOut);
         }
 
       // Add this component to the various section lists.
@@ -228,6 +245,7 @@ int cmCPackNSISGenerator::CompressFiles(const char* outFileName,
       sectionList += compIt->first;
       sectionList += "\"\n";
       selectedVarsList += "Var " + compIt->first + "_selected\n";
+      selectedVarsList += "Var " + compIt->first + "_was_installed\n";
 
       // Add the component description, if any.
       if (!compIt->second.Description.empty())
@@ -238,6 +256,8 @@ int cmCPackNSISGenerator::CompressFiles(const char* outFileName,
         }
       }
 
+    componentCode += macrosOut.str();
+
     if (componentDescriptions.empty() && groupDescriptions.empty())
       {
       // Turn off the "Description" box
@@ -254,12 +274,23 @@ int cmCPackNSISGenerator::CompressFiles(const char* outFileName,
       this->SetOptionIfNotSet("CPACK_NSIS_INSTALLER_MUI_COMPONENTS_DESC", 
                               componentDescriptions.c_str());
       }
+
+    if (anyDownloadedComponents)
+      {
+      defines += "!define CPACK_USES_DOWNLOAD\n";
+      if (cmSystemTools::IsOn(this->GetOption("CPACK_ADD_REMOVE")))
+        {
+        defines += "!define CPACK_NSIS_ADD_REMOVE\n";
+        }
+      }
+
     this->SetOptionIfNotSet("CPACK_NSIS_INSTALLATION_TYPES", installTypesCode.c_str());
     this->SetOptionIfNotSet("CPACK_NSIS_PAGE_COMPONENTS", "!insertmacro MUI_PAGE_COMPONENTS");
     this->SetOptionIfNotSet("CPACK_NSIS_FULL_INSTALL", "");
     this->SetOptionIfNotSet("CPACK_NSIS_COMPONENT_SECTIONS", componentCode.c_str());
     this->SetOptionIfNotSet("CPACK_NSIS_COMPONENT_SECTION_LIST", sectionList.c_str());
     this->SetOptionIfNotSet("CPACK_NSIS_SECTION_SELECTED_VARS", selectedVarsList.c_str());
+    this->SetOption("CPACK_NSIS_DEFINES", defines.c_str());
     }
 
   this->ConfigureFile(nsisInInstallOptions.c_str(), 
@@ -559,7 +590,7 @@ bool cmCPackNSISGenerator::SupportsComponentInstallation() const
 //----------------------------------------------------------------------
 std::string 
 cmCPackNSISGenerator::
-CreateComponentDescription(cmCPackComponent *component) const
+CreateComponentDescription(cmCPackComponent *component, cmOStringStream& macrosOut)
 {
   // Basic description of the component
   std::string componentCode = "Section ";
@@ -590,46 +621,204 @@ CreateComponentDescription(cmCPackComponent *component) const
     componentCode += "  SectionIn" + out.str() + "\n";
     }
   componentCode += "  SetOutPath \"$INSTDIR\"\n";
-  componentCode += "  File /r \"${INST_DIR}\\" + component->Name + "\\*.*\"\n";
+
+  componentCode += "  IntCmp $" + component->Name 
+    + "_was_installed ${SF_SELECTED} noinstall_" + component->Name + "\n";
+
+  // Create the actual installation commands
+  if (component->IsDownloaded)
+    {
+    if (component->ArchiveFile.empty())
+      {
+      // Compute the name of the archive.
+      std::string packagesDir = this->GetOption("CPACK_TEMPORARY_DIRECTORY");
+      packagesDir += ".dummy";
+      cmOStringStream out;
+      out << cmSystemTools::GetFilenameWithoutLastExtension(packagesDir)
+        << "-" << component->Name << ".zip";
+      component->ArchiveFile = out.str();
+      }
+
+    // Create the directory for the upload area
+    const char* userUploadDirectory = this->GetOption("CPACK_UPLOAD_DIRECTORY");
+    std::string uploadDirectory;
+    if (userUploadDirectory && *userUploadDirectory)
+      {
+      uploadDirectory = userUploadDirectory;
+      }
+    else
+      {
+      uploadDirectory= this->GetOption("CPACK_PACKAGE_DIRECTORY");
+      uploadDirectory += "/CPackUploads";
+      }
+    if(!cmSystemTools::FileExists(uploadDirectory.c_str()))
+      {
+      if (!cmSystemTools::MakeDirectory(uploadDirectory.c_str()))
+        {
+        cmCPackLogger(cmCPackLog::LOG_ERROR,
+          "Unable to create NSIS upload directory " << uploadDirectory
+          << std::endl);
+        return "";
+        }
+      }
+
+    // Remove the old archive, if one exists
+    std::string archiveFile = uploadDirectory + '/' + component->ArchiveFile;
+    cmCPackLogger(cmCPackLog::LOG_OUTPUT,
+                  "-   Building downloaded component archive: " 
+                  << archiveFile << std::endl);
+    if (cmSystemTools::FileExists(archiveFile.c_str(), true))
+      {
+        if (!cmSystemTools::RemoveFile(archiveFile.c_str()))
+        {
+        cmCPackLogger(cmCPackLog::LOG_ERROR,
+          "Unable to remove archive file " << archiveFile
+          << std::endl);
+        return "";
+        }
+      }
+
+    // Find a ZIP program
+    if (!this->IsSet("ZIP_EXECUTABLE"))
+      {
+      this->ReadListFile("CPackZIP.cmake");
+
+      if (!this->IsSet("ZIP_EXECUTABLE"))
+        {
+        cmCPackLogger(cmCPackLog::LOG_ERROR,
+          "Unable to find ZIP program"
+          << std::endl);
+        return "";
+        }
+      }
+
+    // The directory where this component's files reside
+    std::string dirName = this->GetOption("CPACK_TEMPORARY_DIRECTORY");
+    dirName += '/';
+    dirName += component->Name;
+    dirName += '/';
+
+    // Build the list of files to go into this archive, and determine the 
+    // size of the installed component.
+    std::string zipListFileName = this->GetOption("CPACK_TEMPORARY_DIRECTORY");
+    zipListFileName += "/winZip.filelist";
+    bool needQuotesInFile 
+      = cmSystemTools::IsOn(this->GetOption("CPACK_ZIP_NEED_QUOTES"));
+    unsigned long totalSize = 0;
+    { // the scope is needed for cmGeneratedFileStream
+      cmGeneratedFileStream out(zipListFileName.c_str());
+      std::vector<std::string>::iterator fileIt;
+      for (fileIt = component->Files.begin(); 
+           fileIt != component->Files.end(); 
+           ++fileIt)
+        {
+        if ( needQuotesInFile )
+          {
+          out << "\"";
+          }
+        out << *fileIt;
+        if ( needQuotesInFile )
+          {
+          out << "\"";
+          }
+        out << std::endl;
+
+        totalSize += cmSystemTools::FileLength((dirName + *fileIt).c_str());
+        }
+    }
+
+    // Build the archive in the upload area
+    std::string cmd = this->GetOption("CPACK_ZIP_COMMAND");
+    cmsys::SystemTools::ReplaceString(cmd, "<ARCHIVE>", archiveFile.c_str());
+    cmsys::SystemTools::ReplaceString(cmd, "<FILELIST>", 
+                                      zipListFileName.c_str());
+    std::string output;
+    int retVal = -1;
+    int res = cmSystemTools::RunSingleCommand(cmd.c_str(), &output, &retVal, 
+                                              dirName.c_str(), false, 0);
+    if ( !res || retVal )
+    {
+      std::string tmpFile = this->GetOption("CPACK_TOPLEVEL_DIRECTORY");
+      tmpFile += "/CompressZip.log";
+      cmGeneratedFileStream ofs(tmpFile.c_str());
+      ofs << "# Run command: " << cmd.c_str() << std::endl
+        << "# Output:" << std::endl
+        << output.c_str() << std::endl;
+      cmCPackLogger(cmCPackLog::LOG_ERROR, "Problem running zip command: "
+        << cmd.c_str() << std::endl
+        << "Please check " << tmpFile.c_str() << " for errors" << std::endl);
+      return "";
+    }
+    
+    // Create the NSIS code to download this file on-the-fly.
+    unsigned totalSizeInKbytes = (totalSize + 512) / 1024;
+    if (totalSizeInKbytes == 0)
+      {
+      totalSizeInKbytes = 1;
+      }
+    cmOStringStream out;
+    out << "  AddSize " << totalSizeInKbytes << "\n"
+        << "  Push \"" << component->ArchiveFile << "\"\n"
+        << "  Call DownloadFile\n"
+        << "  ZipDLL::extractall \"$INSTDIR\\" 
+        << component->ArchiveFile << "\" \"$INSTDIR\"\n"
+        <<  "  Pop $2 ; error message\n"
+                     "  StrCmp $2 \"success\" +2 0\n"
+                     "  MessageBox MB_OK \"Failed to unzip $2\"\n"
+                     "  Delete $INSTDIR\\$0\n";
+    componentCode += out.str();
+    }
+  else
+    {
+    componentCode += "  File /r \"${INST_DIR}\\" + component->Name + "\\*.*\"\n";
+    }
+  componentCode += "  noinstall_" + component->Name + ":\n";
   componentCode += "SectionEnd\n";
 
   // Macro used to remove the component
-  componentCode += "!macro Remove_${" + component->Name + "}\n";
+  macrosOut << "!macro Remove_${" << component->Name << "}\n";
+  macrosOut << "  IntCmp $" << component->Name << "_was_installed 0 noremove_"
+            << component->Name << "\n";
   std::vector<std::string>::iterator pathIt;
   for (pathIt = component->Files.begin(); 
        pathIt != component->Files.end(); 
        ++pathIt) 
     {
-    componentCode += "  Delete \"$INSTDIR\\" + *pathIt + "\"\n";
+    macrosOut << "  Delete \"$INSTDIR\\" 
+              << cmSystemTools::ConvertToWindowsOutputPath(pathIt->c_str())
+              << "\"\n";
     }
   for (pathIt = component->Directories.begin(); 
        pathIt != component->Directories.end(); 
        ++pathIt) 
     {
-    componentCode += "  RMDir \"$INSTDIR\\" + *pathIt + "\"\n";
+    macrosOut << "  RMDir \"$INSTDIR\\" 
+              << cmSystemTools::ConvertToWindowsOutputPath(pathIt->c_str())
+              << "\"\n";
     }
-  componentCode += "!macroend\n";
+  macrosOut << "  noremove_" << component->Name << ":\n";
+  macrosOut << "!macroend\n";
 
   // Macro used to select each of the components that this component
   // depends on.
   std::set<cmCPackComponent *> visited;
-  componentCode += "!macro Select_" + component->Name + "_depends\n";
-  componentCode += CreateSelectionDependenciesDescription(component, visited);
-  componentCode += "!macroend\n";
+  macrosOut << "!macro Select_" << component->Name << "_depends\n";
+  macrosOut << CreateSelectionDependenciesDescription(component, visited);
+  macrosOut << "!macroend\n";
 
   // Macro used to deselect each of the components that depend on this
   // component.
   visited.clear();
-  componentCode += "!macro Deselect_required_by_" + component->Name + "\n";
-  componentCode += CreateDeselectionDependenciesDescription(component, visited);
-  componentCode += "!macroend\n";
+  macrosOut << "!macro Deselect_required_by_" << component->Name << "\n";
+  macrosOut << CreateDeselectionDependenciesDescription(component, visited);
+  macrosOut << "!macroend\n";
   return componentCode;
 }
 
 //----------------------------------------------------------------------
 std::string cmCPackNSISGenerator::CreateSelectionDependenciesDescription
               (cmCPackComponent *component,
-               std::set<cmCPackComponent *>& visited) const
+               std::set<cmCPackComponent *>& visited)
 {
   // Don't visit a component twice
   if (visited.count(component)) 
@@ -660,7 +849,7 @@ std::string cmCPackNSISGenerator::CreateSelectionDependenciesDescription
 //----------------------------------------------------------------------
 std::string cmCPackNSISGenerator::CreateDeselectionDependenciesDescription
               (cmCPackComponent *component,
-                   std::set<cmCPackComponent *>& visited) const
+                   std::set<cmCPackComponent *>& visited)
 {
   // Don't visit a component twice
   if (visited.count(component)) 
@@ -692,9 +881,10 @@ std::string cmCPackNSISGenerator::CreateDeselectionDependenciesDescription
 //----------------------------------------------------------------------
 std::string 
 cmCPackNSISGenerator::
-CreateComponentGroupDescription(cmCPackComponentGroup *group) const
+CreateComponentGroupDescription(cmCPackComponentGroup *group, 
+                                cmOStringStream& macrosOut)
 {
-  if (group->Components.empty())
+  if (group->Components.empty() && group->Subgroups.empty())
     {
     // Silently skip empty groups. NSIS doesn't support them.
     return std::string();
@@ -713,12 +903,25 @@ CreateComponentGroupDescription(cmCPackComponentGroup *group) const
     {
     code += "\"" + group->DisplayName + "\" " + group->Name + "\n";
     }
+
+  std::vector<cmCPackComponentGroup*>::iterator groupIt;
+  for (groupIt = group->Subgroups.begin(); groupIt != group->Subgroups.end();
+       ++groupIt)
+    {
+    code += this->CreateComponentGroupDescription(*groupIt, macrosOut);
+    }
+
   std::vector<cmCPackComponent*>::iterator comp;
   for (comp = group->Components.begin(); 
        comp != group->Components.end(); 
        ++comp)
     {
-    code += this->CreateComponentDescription(*comp);
+    if ((*comp)->Files.empty())
+      {
+      continue;
+      }
+
+    code += this->CreateComponentDescription(*comp, macrosOut);
     }
   code += "SectionGroupEnd\n";
   return code;
diff --git a/Source/CPack/cmCPackNSISGenerator.h b/Source/CPack/cmCPackNSISGenerator.h
index 70068e41..5299a91 100644
--- a/Source/CPack/cmCPackNSISGenerator.h
+++ b/Source/CPack/cmCPackNSISGenerator.h
@@ -53,24 +53,30 @@ protected:
   virtual bool SupportsComponentInstallation() const;
 
   /// Produce a string that contains the NSIS code to describe a 
-  /// particular component.
-  std::string CreateComponentDescription(cmCPackComponent *component) const;
+  /// particular component. Any added macros will be emitted via 
+  /// macrosOut.
+  std::string 
+  CreateComponentDescription(cmCPackComponent *component,
+                             cmOStringStream& macrosOut);
 
   /// Produce NSIS code that selects all of the components that this component
   /// depends on, recursively.
   std::string CreateSelectionDependenciesDescription
                 (cmCPackComponent *component,
-                 std::set<cmCPackComponent *>& visited) const;
+                 std::set<cmCPackComponent *>& visited);
 
   /// Produce NSIS code that de-selects all of the components that are dependent
   /// on this component, recursively.
   std::string CreateDeselectionDependenciesDescription
                 (cmCPackComponent *component,
-                 std::set<cmCPackComponent *>& visited) const;
+                 std::set<cmCPackComponent *>& visited);
 
   /// Produce a string that contains the NSIS code to describe a 
-  /// particular component group, including its components.
-  std::string CreateComponentGroupDescription(cmCPackComponentGroup *group) const;
+  /// particular component group, including its components. Any
+  /// added macros will be emitted via macrosOut.
+  std::string 
+  CreateComponentGroupDescription(cmCPackComponentGroup *group,
+                                  cmOStringStream& macrosOut);
 
   /// Translations any newlines found in the string into \r\n, so that the 
   /// resulting string can be used within NSIS.
diff --git a/Source/CPack/cmCPackPackageMakerGenerator.cxx b/Source/CPack/cmCPackPackageMakerGenerator.cxx
index 04b7899..a156971 100644
--- a/Source/CPack/cmCPackPackageMakerGenerator.cxx
+++ b/Source/CPack/cmCPackPackageMakerGenerator.cxx
@@ -580,7 +580,10 @@ WriteDistributionFile(const char* metapackageFile)
        groupIt != this->ComponentGroups.end(); 
        ++groupIt)
     {
-    CreateChoiceOutline(groupIt->second, choiceOut);
+    if (groupIt->second.ParentGroup == 0)
+      {
+      CreateChoiceOutline(groupIt->second, choiceOut);
+      }
     }
 
   // Emit the outline for the non-grouped components
@@ -622,6 +625,13 @@ cmCPackPackageMakerGenerator::
 CreateChoiceOutline(const cmCPackComponentGroup& group, cmOStringStream& out)
 {
   out << "<line choice=\"" << group.Name << "Choice\">" << std::endl;
+  std::vector<cmCPackComponentGroup*>::const_iterator groupIt;
+  for (groupIt = group.Subgroups.begin(); groupIt != group.Subgroups.end();
+       ++groupIt)
+    {
+    CreateChoiceOutline(**groupIt, out);
+    }
+
   std::vector<cmCPackComponent*>::const_iterator compIt;
   for (compIt = group.Components.begin(); compIt != group.Components.end();
        ++compIt)
diff --git a/Source/cmGetCMakePropertyCommand.cxx b/Source/cmGetCMakePropertyCommand.cxx
index 09e7068..02e21bd 100644
--- a/Source/cmGetCMakePropertyCommand.cxx
+++ b/Source/cmGetCMakePropertyCommand.cxx
@@ -49,6 +49,22 @@ bool cmGetCMakePropertyCommand
     {
     this->Makefile->GetListOfMacros(output);
     }
+  else if ( args[1] == "COMPONENTS" )
+    {
+    const std::set<cmStdString>* components
+      = this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+        ->GetInstallComponents();
+    std::set<cmStdString>::const_iterator compIt;
+    output = "";
+    for (compIt = components->begin(); compIt != components->end(); ++compIt)
+      {
+      if (compIt != components->begin())
+        {
+        output += ";";
+        }
+      output += *compIt;
+      }
+    }
   else
     {
     const char *prop = 
diff --git a/Source/cmGetCMakePropertyCommand.h b/Source/cmGetCMakePropertyCommand.h
index c1f66d9..b3cb442 100644
--- a/Source/cmGetCMakePropertyCommand.h
+++ b/Source/cmGetCMakePropertyCommand.h
@@ -62,7 +62,8 @@ public:
         "Get a property from the CMake instance.  The value of the "
         "property is stored in the variable VAR. If the property is "
         "not found, CMake will report an error. Some supported properties "
-        "include: VARIABLES, CACHE_VARIABLES, COMMANDS, and MACROS.";
+        "include: VARIABLES, CACHE_VARIABLES, COMMANDS, MACROS, and "
+        "COMPONENTS.";
     }
   
   cmTypeMacro(cmGetCMakePropertyCommand, cmCommand);
diff --git a/Source/cmGlobalGenerator.h b/Source/cmGlobalGenerator.h
index 2865a38..a76890b 100644
--- a/Source/cmGlobalGenerator.h
+++ b/Source/cmGlobalGenerator.h
@@ -139,6 +139,9 @@ public:
 
   void AddInstallComponent(const char* component);
 
+  const std::set<cmStdString>* GetInstallComponents() const 
+  { return &InstallComponents; }
+
   ///! Add one installed target to the sets of the exports
   void AddTargetToExports(const char* exportSet, cmTarget* target, 
                           cmInstallTargetGenerator* archive,
diff --git a/Source/cmInstallCommand.cxx b/Source/cmInstallCommand.cxx
index 6ce7ae5..eb162f5 100644
--- a/Source/cmInstallCommand.cxx
+++ b/Source/cmInstallCommand.cxx
@@ -384,6 +384,17 @@ bool cmInstallCommand::HandleTargetsMode(std::vector<std::string> const& args)
         }
     }
 
+  // Keep track of whether we will be performing an installation of
+  // any files of the given type.
+  bool installsArchive = false;
+  bool installsLibrary = false;
+  bool installsRuntime = false;
+  bool installsFramework = false;
+  bool installsBundle = false;
+  bool installsPrivateHeader = false;
+  bool installsPublicHeader = false;
+  bool installsResource = false;
+
   // Generate install script code to install the given targets.
   for(std::vector<cmTarget*>::iterator ti = targets.begin();
       ti != targets.end(); ++ti)
@@ -691,6 +702,16 @@ bool cmInstallCommand::HandleTargetsMode(std::vector<std::string> const& args)
       }
     }
 
+    // Keep track of whether we're installing anything in each category
+    installsArchive = installsArchive || archiveGenerator != 0;
+    installsLibrary = installsLibrary || libraryGenerator != 0;
+    installsRuntime = installsRuntime || runtimeGenerator != 0;
+    installsFramework = installsFramework || frameworkGenerator != 0;
+    installsBundle = installsBundle || bundleGenerator != 0;
+    installsPrivateHeader = installsPrivateHeader || privateHeaderGenerator != 0;
+    installsPublicHeader = installsPublicHeader || publicHeaderGenerator != 0;
+    installsResource = installsResource || resourceGenerator;
+
     this->Makefile->AddInstallGenerator(archiveGenerator);
     this->Makefile->AddInstallGenerator(libraryGenerator);
     this->Makefile->AddInstallGenerator(runtimeGenerator);
@@ -713,22 +734,46 @@ bool cmInstallCommand::HandleTargetsMode(std::vector<std::string> const& args)
     }
 
   // Tell the global generator about any installation component names specified
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                     ->AddInstallComponent(archiveArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                     ->AddInstallComponent(libraryArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                     ->AddInstallComponent(runtimeArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                   ->AddInstallComponent(frameworkArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                      ->AddInstallComponent(bundleArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-               ->AddInstallComponent(privateHeaderArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                ->AddInstallComponent(publicHeaderArgs.GetComponent().c_str());
-  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
-                    ->AddInstallComponent(resourceArgs.GetComponent().c_str());
+  if (installsArchive)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                       ->AddInstallComponent(archiveArgs.GetComponent().c_str());
+    }
+  if (installsLibrary)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                       ->AddInstallComponent(libraryArgs.GetComponent().c_str());
+    }
+  if (installsRuntime)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                       ->AddInstallComponent(runtimeArgs.GetComponent().c_str());
+    }
+  if (installsFramework)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                     ->AddInstallComponent(frameworkArgs.GetComponent().c_str());
+    }
+  if (installsBundle)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                        ->AddInstallComponent(bundleArgs.GetComponent().c_str());
+    }
+  if (installsPrivateHeader)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                 ->AddInstallComponent(privateHeaderArgs.GetComponent().c_str());
+    }
+  if (installsPublicHeader)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                  ->AddInstallComponent(publicHeaderArgs.GetComponent().c_str());
+    }
+  if (installsResource)
+    {
+    this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                      ->AddInstallComponent(resourceArgs.GetComponent().c_str());
+    }
 
   return true;
 }
diff --git a/Source/cmInstallFilesCommand.cxx b/Source/cmInstallFilesCommand.cxx
index 36e7e25..a352244 100644
--- a/Source/cmInstallFilesCommand.cxx
+++ b/Source/cmInstallFilesCommand.cxx
@@ -59,6 +59,9 @@ bool cmInstallFilesCommand
       }
     }
   
+  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                       ->AddInstallComponent("Unspecified");
+
   return true;
 }
 
@@ -126,7 +129,7 @@ void cmInstallFilesCommand::CreateInstallGenerator() const
   // Use a file install generator.
   const char* no_permissions = "";
   const char* no_rename = "";
-  const char* no_component = "";
+  const char* no_component = "Unspecified";
   std::vector<std::string> no_configurations;
   this->Makefile->AddInstallGenerator(
     new cmInstallFilesGenerator(this->Files,
diff --git a/Source/cmInstallProgramsCommand.cxx b/Source/cmInstallProgramsCommand.cxx
index 6a55f17..d7557d0 100644
--- a/Source/cmInstallProgramsCommand.cxx
+++ b/Source/cmInstallProgramsCommand.cxx
@@ -38,6 +38,9 @@ bool cmInstallProgramsCommand
     this->FinalArgs.push_back(*s);
     }  
   
+  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                       ->AddInstallComponent("Unspecified");
+
   return true;
 }
 
@@ -87,7 +90,7 @@ void cmInstallProgramsCommand::FinalPass()
   // Use a file install generator.
   const char* no_permissions = "";
   const char* no_rename = "";
-  const char* no_component = "";
+  const char* no_component = "Unspecified";
   std::vector<std::string> no_configurations;
   this->Makefile->AddInstallGenerator(
     new cmInstallFilesGenerator(this->Files,
diff --git a/Source/cmInstallTargetGenerator.h b/Source/cmInstallTargetGenerator.h
index 61357b3..cd4d6e5 100644
--- a/Source/cmInstallTargetGenerator.h
+++ b/Source/cmInstallTargetGenerator.h
@@ -31,7 +31,7 @@ public:
     const char* file_permissions = "",
     std::vector<std::string> const& configurations 
     = std::vector<std::string>(),
-    const char* component = "",
+    const char* component = "Unspecified",
     bool optional = false
     );
   virtual ~cmInstallTargetGenerator();
diff --git a/Source/cmInstallTargetsCommand.cxx b/Source/cmInstallTargetsCommand.cxx
index d3ecddf..cfcdc0c 100644
--- a/Source/cmInstallTargetsCommand.cxx
+++ b/Source/cmInstallTargetsCommand.cxx
@@ -62,6 +62,9 @@ bool cmInstallTargetsCommand
       }
     }
 
+  this->Makefile->GetLocalGenerator()->GetGlobalGenerator()
+                       ->AddInstallComponent("Unspecified");
+
   return true;
 }