ExternalData: Convert docs to a bracket comment

Use a bracket comment to hold the documentation instead of a block of
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Modules/ExternalData.cmake

@@ -1,189 +1,190 @@
-#.rst:
-# ExternalData
-# ------------
-#
-# Manage data files stored outside source tree
-#
-# Use this module to unambiguously reference data files stored outside
-# the source tree and fetch them at build time from arbitrary local and
-# remote content-addressed locations.  Functions provided by this module
-# recognize arguments with the syntax ``DATA{<name>}`` as references to
-# external data, replace them with full paths to local copies of those
-# data, and create build rules to fetch and update the local copies.
-#
-# The ``DATA{}`` syntax is literal and the ``<name>`` is a full or relative path
-# within the source tree.  The source tree must contain either a real
-# data file at ``<name>`` or a "content link" at ``<name><ext>`` containing a
-# hash of the real file using a hash algorithm corresponding to ``<ext>``.
-# For example, the argument ``DATA{img.png}`` may be satisfied by either a
-# real ``img.png`` file in the current source directory or a ``img.png.md5``
-# file containing its MD5 sum.
-#
-# The ``ExternalData_Expand_Arguments`` function evaluates ``DATA{}``
-# references in its arguments and constructs a new list of arguments:
-#
-# .. code-block:: cmake
-#
-#  ExternalData_Expand_Arguments(
-#    <target>   # Name of data management target
-#    <outVar>   # Output variable
-#    [args...]  # Input arguments, DATA{} allowed
-#    )
-#
-# It replaces each ``DATA{}`` reference in an argument with the full path of
-# a real data file on disk that will exist after the ``<target>`` builds.
-#
-# The ``ExternalData_Add_Test`` function wraps around the CMake
-# :command:`add_test` command but supports ``DATA{}`` references in
-# its arguments:
-#
-# .. code-block:: cmake
-#
-#  ExternalData_Add_Test(
-#    <target>   # Name of data management target
-#    ...        # Arguments of add_test(), DATA{} allowed
-#    )
-#
-# It passes its arguments through ``ExternalData_Expand_Arguments`` and then
-# invokes the :command:`add_test` command using the results.
-#
-# The ``ExternalData_Add_Target`` function creates a custom target to
-# manage local instances of data files stored externally:
-#
-# .. code-block:: cmake
-#
-#  ExternalData_Add_Target(
-#    <target>   # Name of data management target
-#    )
-#
-# It creates custom commands in the target as necessary to make data
-# files available for each ``DATA{}`` reference previously evaluated by
-# other functions provided by this module.  A list of URL templates may
-# be provided in the variable ``ExternalData_URL_TEMPLATES`` using the
-# placeholders ``%(algo)`` and ``%(hash)`` in each template.  Data fetch
-# rules try each URL template in order by substituting the hash
-# algorithm name for ``%(algo)`` and the hash value for ``%(hash)``.
-#
-# The following hash algorithms are supported::
-#
-#  %(algo)     <ext>     Description
-#  -------     -----     -----------
-#  MD5         .md5      Message-Digest Algorithm 5, RFC 1321
-#  SHA1        .sha1     US Secure Hash Algorithm 1, RFC 3174
-#  SHA224      .sha224   US Secure Hash Algorithms, RFC 4634
-#  SHA256      .sha256   US Secure Hash Algorithms, RFC 4634
-#  SHA384      .sha384   US Secure Hash Algorithms, RFC 4634
-#  SHA512      .sha512   US Secure Hash Algorithms, RFC 4634
-#
-# Note that the hashes are used only for unique data identification and
-# download verification.
-#
-# Example usage:
-#
-# .. code-block:: cmake
-#
-#  include(ExternalData)
-#  set(ExternalData_URL_TEMPLATES "file:///local/%(algo)/%(hash)"
-#                                 "file:////host/share/%(algo)/%(hash)"
-#                                 "http://data.org/%(algo)/%(hash)")
-#  ExternalData_Add_Test(MyData
-#    NAME MyTest
-#    COMMAND MyExe DATA{MyInput.png}
-#    )
-#  ExternalData_Add_Target(MyData)
-#
-# When test ``MyTest`` runs the ``DATA{MyInput.png}`` argument will be
-# replaced by the full path to a real instance of the data file
-# ``MyInput.png`` on disk.  If the source tree contains a content link
-# such as ``MyInput.png.md5`` then the ``MyData`` target creates a real
-# ``MyInput.png`` in the build tree.
-#
-# The ``DATA{}`` syntax can be told to fetch a file series using the form
-# ``DATA{<name>,:}``, where the ``:`` is literal.  If the source tree
-# contains a group of files or content links named like a series then a
-# reference to one member adds rules to fetch all of them.  Although all
-# members of a series are fetched, only the file originally named by the
-# ``DATA{}`` argument is substituted for it.  The default configuration
-# recognizes file series names ending with ``#.ext``, ``_#.ext``, ``.#.ext``,
-# or ``-#.ext`` where ``#`` is a sequence of decimal digits and ``.ext`` is
-# any single extension.  Configure it with a regex that parses ``<number>``
-# and ``<suffix>`` parts from the end of ``<name>``::
-#
-#  ExternalData_SERIES_PARSE = regex of the form (<number>)(<suffix>)$
-#
-# For more complicated cases set::
-#
-#  ExternalData_SERIES_PARSE = regex with at least two () groups
-#  ExternalData_SERIES_PARSE_PREFIX = <prefix> regex group number, if any
-#  ExternalData_SERIES_PARSE_NUMBER = <number> regex group number
-#  ExternalData_SERIES_PARSE_SUFFIX = <suffix> regex group number
-#
-# Configure series number matching with a regex that matches the
-# ``<number>`` part of series members named ``<prefix><number><suffix>``::
-#
-#  ExternalData_SERIES_MATCH = regex matching <number> in all series members
-#
-# Note that the ``<suffix>`` of a series does not include a hash-algorithm
-# extension.
-#
-# The ``DATA{}`` syntax can alternatively match files associated with the
-# named file and contained in the same directory.  Associated files may
-# be specified by options using the syntax
-# ``DATA{<name>,<opt1>,<opt2>,...}``.  Each option may specify one file by
-# name or specify a regular expression to match file names using the
-# syntax ``REGEX:<regex>``.  For example, the arguments::
-#
-#  DATA{MyData/MyInput.mhd,MyInput.img}                   # File pair
-#  DATA{MyData/MyFrames00.png,REGEX:MyFrames[0-9]+\\.png} # Series
-#
-# will pass ``MyInput.mha`` and ``MyFrames00.png`` on the command line but
-# ensure that the associated files are present next to them.
-#
-# The ``DATA{}`` syntax may reference a directory using a trailing slash and
-# a list of associated files.  The form ``DATA{<name>/,<opt1>,<opt2>,...}``
-# adds rules to fetch any files in the directory that match one of the
-# associated file options.  For example, the argument
-# ``DATA{MyDataDir/,REGEX:.*}`` will pass the full path to a ``MyDataDir``
-# directory on the command line and ensure that the directory contains
-# files corresponding to every file or content link in the ``MyDataDir``
-# source directory.
-#
-# The variable ``ExternalData_LINK_CONTENT`` may be set to the name of a
-# supported hash algorithm to enable automatic conversion of real data
-# files referenced by the ``DATA{}`` syntax into content links.  For each
-# such ``<file>`` a content link named ``<file><ext>`` is created.  The
-# original file is renamed to the form ``.ExternalData_<algo>_<hash>`` to
-# stage it for future transmission to one of the locations in the list
-# of URL templates (by means outside the scope of this module).  The
-# data fetch rule created for the content link will use the staged
-# object if it cannot be found using any URL template.
-#
-# The variable ``ExternalData_OBJECT_STORES`` may be set to a list of local
-# directories that store objects using the layout ``<dir>/%(algo)/%(hash)``.
-# These directories will be searched first for a needed object.  If the
-# object is not available in any store then it will be fetched remotely
-# using the URL templates and added to the first local store listed.  If
-# no stores are specified the default is a location inside the build
-# tree.
-#
-# The variable ``ExternalData_SOURCE_ROOT`` may be set to the highest source
-# directory containing any path named by a ``DATA{}`` reference.  The
-# default is ``CMAKE_SOURCE_DIR``.  ``ExternalData_SOURCE_ROOT`` and
-# ``CMAKE_SOURCE_DIR`` must refer to directories within a single source
-# distribution (e.g.  they come together in one tarball).
-#
-# The variable ``ExternalData_BINARY_ROOT`` may be set to the directory to
-# hold the real data files named by expanded ``DATA{}`` references.  The
-# default is ``CMAKE_BINARY_DIR``.  The directory layout will mirror that of
-# content links under ``ExternalData_SOURCE_ROOT``.
-#
-# Variables ``ExternalData_TIMEOUT_INACTIVITY`` and
-# ``ExternalData_TIMEOUT_ABSOLUTE`` set the download inactivity and absolute
-# timeouts, in seconds.  The defaults are 60 seconds and 300 seconds,
-# respectively.  Set either timeout to 0 seconds to disable enforcement.
+#[=======================================================================[.rst:
+ExternalData
+------------
+
+Manage data files stored outside source tree
+
+Use this module to unambiguously reference data files stored outside
+the source tree and fetch them at build time from arbitrary local and
+remote content-addressed locations.  Functions provided by this module
+recognize arguments with the syntax ``DATA{<name>}`` as references to
+external data, replace them with full paths to local copies of those
+data, and create build rules to fetch and update the local copies.
+
+The ``DATA{}`` syntax is literal and the ``<name>`` is a full or relative path
+within the source tree.  The source tree must contain either a real
+data file at ``<name>`` or a "content link" at ``<name><ext>`` containing a
+hash of the real file using a hash algorithm corresponding to ``<ext>``.
+For example, the argument ``DATA{img.png}`` may be satisfied by either a
+real ``img.png`` file in the current source directory or a ``img.png.md5``
+file containing its MD5 sum.
+
+The ``ExternalData_Expand_Arguments`` function evaluates ``DATA{}``
+references in its arguments and constructs a new list of arguments:
+
+.. code-block:: cmake
+
+ ExternalData_Expand_Arguments(
+   <target>   # Name of data management target
+   <outVar>   # Output variable
+   [args...]  # Input arguments, DATA{} allowed
+   )
+
+It replaces each ``DATA{}`` reference in an argument with the full path of
+a real data file on disk that will exist after the ``<target>`` builds.
+
+The ``ExternalData_Add_Test`` function wraps around the CMake
+:command:`add_test` command but supports ``DATA{}`` references in
+its arguments:
+
+.. code-block:: cmake
+
+ ExternalData_Add_Test(
+   <target>   # Name of data management target
+   ...        # Arguments of add_test(), DATA{} allowed
+   )
+
+It passes its arguments through ``ExternalData_Expand_Arguments`` and then
+invokes the :command:`add_test` command using the results.
+
+The ``ExternalData_Add_Target`` function creates a custom target to
+manage local instances of data files stored externally:
+
+.. code-block:: cmake
+
+ ExternalData_Add_Target(
+   <target>   # Name of data management target
+   )
+
+It creates custom commands in the target as necessary to make data
+files available for each ``DATA{}`` reference previously evaluated by
+other functions provided by this module.  A list of URL templates may
+be provided in the variable ``ExternalData_URL_TEMPLATES`` using the
+placeholders ``%(algo)`` and ``%(hash)`` in each template.  Data fetch
+rules try each URL template in order by substituting the hash
+algorithm name for ``%(algo)`` and the hash value for ``%(hash)``.
+
+The following hash algorithms are supported::
+
+ %(algo)     <ext>     Description
+ -------     -----     -----------
+ MD5         .md5      Message-Digest Algorithm 5, RFC 1321
+ SHA1        .sha1     US Secure Hash Algorithm 1, RFC 3174
+ SHA224      .sha224   US Secure Hash Algorithms, RFC 4634
+ SHA256      .sha256   US Secure Hash Algorithms, RFC 4634
+ SHA384      .sha384   US Secure Hash Algorithms, RFC 4634
+ SHA512      .sha512   US Secure Hash Algorithms, RFC 4634
+
+Note that the hashes are used only for unique data identification and
+download verification.
+
+Example usage:
+
+.. code-block:: cmake
+
+ include(ExternalData)
+ set(ExternalData_URL_TEMPLATES "file:///local/%(algo)/%(hash)"
+                                "file:////host/share/%(algo)/%(hash)"
+                                "http://data.org/%(algo)/%(hash)")
+ ExternalData_Add_Test(MyData
+   NAME MyTest
+   COMMAND MyExe DATA{MyInput.png}
+   )
+ ExternalData_Add_Target(MyData)
+
+When test ``MyTest`` runs the ``DATA{MyInput.png}`` argument will be
+replaced by the full path to a real instance of the data file
+``MyInput.png`` on disk.  If the source tree contains a content link
+such as ``MyInput.png.md5`` then the ``MyData`` target creates a real
+``MyInput.png`` in the build tree.
+
+The ``DATA{}`` syntax can be told to fetch a file series using the form
+``DATA{<name>,:}``, where the ``:`` is literal.  If the source tree
+contains a group of files or content links named like a series then a
+reference to one member adds rules to fetch all of them.  Although all
+members of a series are fetched, only the file originally named by the
+``DATA{}`` argument is substituted for it.  The default configuration
+recognizes file series names ending with ``#.ext``, ``_#.ext``, ``.#.ext``,
+or ``-#.ext`` where ``#`` is a sequence of decimal digits and ``.ext`` is
+any single extension.  Configure it with a regex that parses ``<number>``
+and ``<suffix>`` parts from the end of ``<name>``::
+
+ ExternalData_SERIES_PARSE = regex of the form (<number>)(<suffix>)$
+
+For more complicated cases set::
+
+ ExternalData_SERIES_PARSE = regex with at least two () groups
+ ExternalData_SERIES_PARSE_PREFIX = <prefix> regex group number, if any
+ ExternalData_SERIES_PARSE_NUMBER = <number> regex group number
+ ExternalData_SERIES_PARSE_SUFFIX = <suffix> regex group number
+
+Configure series number matching with a regex that matches the
+``<number>`` part of series members named ``<prefix><number><suffix>``::
+
+ ExternalData_SERIES_MATCH = regex matching <number> in all series members
+
+Note that the ``<suffix>`` of a series does not include a hash-algorithm
+extension.
+
+The ``DATA{}`` syntax can alternatively match files associated with the
+named file and contained in the same directory.  Associated files may
+be specified by options using the syntax
+``DATA{<name>,<opt1>,<opt2>,...}``.  Each option may specify one file by
+name or specify a regular expression to match file names using the
+syntax ``REGEX:<regex>``.  For example, the arguments::
+
+ DATA{MyData/MyInput.mhd,MyInput.img}                   # File pair
+ DATA{MyData/MyFrames00.png,REGEX:MyFrames[0-9]+\\.png} # Series
+
+will pass ``MyInput.mha`` and ``MyFrames00.png`` on the command line but
+ensure that the associated files are present next to them.
+
+The ``DATA{}`` syntax may reference a directory using a trailing slash and
+a list of associated files.  The form ``DATA{<name>/,<opt1>,<opt2>,...}``
+adds rules to fetch any files in the directory that match one of the
+associated file options.  For example, the argument
+``DATA{MyDataDir/,REGEX:.*}`` will pass the full path to a ``MyDataDir``
+directory on the command line and ensure that the directory contains
+files corresponding to every file or content link in the ``MyDataDir``
+source directory.
+
+The variable ``ExternalData_LINK_CONTENT`` may be set to the name of a
+supported hash algorithm to enable automatic conversion of real data
+files referenced by the ``DATA{}`` syntax into content links.  For each
+such ``<file>`` a content link named ``<file><ext>`` is created.  The
+original file is renamed to the form ``.ExternalData_<algo>_<hash>`` to
+stage it for future transmission to one of the locations in the list
+of URL templates (by means outside the scope of this module).  The
+data fetch rule created for the content link will use the staged
+object if it cannot be found using any URL template.
+
+The variable ``ExternalData_OBJECT_STORES`` may be set to a list of local
+directories that store objects using the layout ``<dir>/%(algo)/%(hash)``.
+These directories will be searched first for a needed object.  If the
+object is not available in any store then it will be fetched remotely
+using the URL templates and added to the first local store listed.  If
+no stores are specified the default is a location inside the build
+tree.
+
+The variable ``ExternalData_SOURCE_ROOT`` may be set to the highest source
+directory containing any path named by a ``DATA{}`` reference.  The
+default is ``CMAKE_SOURCE_DIR``.  ``ExternalData_SOURCE_ROOT`` and
+``CMAKE_SOURCE_DIR`` must refer to directories within a single source
+distribution (e.g.  they come together in one tarball).
+
+The variable ``ExternalData_BINARY_ROOT`` may be set to the directory to
+hold the real data files named by expanded ``DATA{}`` references.  The
+default is ``CMAKE_BINARY_DIR``.  The directory layout will mirror that of
+content links under ``ExternalData_SOURCE_ROOT``.
+
+Variables ``ExternalData_TIMEOUT_INACTIVITY`` and
+``ExternalData_TIMEOUT_ABSOLUTE`` set the download inactivity and absolute
+timeouts, in seconds.  The defaults are 60 seconds and 300 seconds,
+respectively.  Set either timeout to 0 seconds to disable enforcement.
+#]=======================================================================]
 
 #=============================================================================
-# Copyright 2010-2013 Kitware, Inc.
+# Copyright 2010-2015 Kitware, Inc.
 #
 # Distributed under the OSI-approved BSD License (the "License");
 # see accompanying file Copyright.txt for details.