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Article contents:== Outdated egg! This is an egg for CHICKEN 4, the unsupported old release. You're almost certainly looking for [[/eggref/5/hfs+|the CHICKEN 5 version of this egg]], if it exists. If it does not exist, there may be equivalent functionality provided by another egg; have a look at the [[https://wiki.call-cc.org/chicken-projects/egg-index-5.html|egg index]]. Otherwise, please consider porting this egg to the current version of CHICKEN. == hfs+ [[toc:]] === Synopsis '''hfs+''' is a interface to the HFS+ filesystem on Mac OS X 10.4 and above. The current implementation provides access to HFS+ extended attributes, including resource forks. It also implements an interface to {{copyfile(3)}}. === Interface ==== Overview All calls taking a {{FILE}} argument accept either a filename or an open POSIX file descriptor. All calls taking an {{ATTRIBUTE}} argument accept either a string or a symbol. All extended attribute calls allow the following options: <nowiki> <table> <tr><td>#:no-follow</td><td>Do not follow symlinks; operate on the symlink itself.</td></tr> </table> </nowiki> ==== list-extended-attributes <procedure>(list-extended-attributes file . options)</procedure> List extended attribute names of {{FILE}}. Returns a list containing one string per attribute name. (list-extended-attributes "examples.scm" #:no-follow) ; => ("com.apple.FinderInfo" "com.apple.ResourceFork") ==== get-extended-attribute <procedure>(get-extended-attribute file attribute . options)</procedure> Get the value of extended attribute {{ATTRIBUTE}} from {{FILE}}. Returns a string representing the value. The string may contain binary data. Returns {{#f}} if the attribute does not exist. ==== set-extended-attribute! <procedure>(set-extended-attribute! file attribute value . options)</procedure> Set extended attribute {{ATTRIBUTE}} on {{FILE}} to {{VALUE}}, and return an unspecified value. {{VALUE}} may be a string or a blob. In addition to {{#:no-follow}}, {{set-extended-attribute!}} allows the following two mutually-exclusive options: <nowiki> <table> <tr><td>#:create</td><td>Raise error if attribute exists.</td></tr> <tr><td>#:replace</td><td>Raise error if attribute does not exist.</td></tr> </table> </nowiki> If neither option is specified, existing attribute values are silently overwritten. (set-extended-attribute! "examples.scm" 'org.callcc "courtesy of Chicken") (get-extended-attribute "examples.scm" 'org.callcc) ; => "courtesy of Chicken" ==== remove-extended-attribute! <procedure>(remove-extended-attribute! file attribute . options)</procedure> Remove extended attribute {{ATTRIBUTE}} from {{FILE}}. By default, if {{ATTRIBUTE}} does not exist, an error is signaled. {{remove-extended-attribute!}} also accepts the following options: <nowiki> <table> <tr><td>#:silent</td><td>Do not raise an error if the attribute is missing.</td></tr> </table> </nowiki> The #:silent option is useful if, for example, you wish to truncate a resource fork but are not sure if one is already present. See below for an example. ==== copyfile <procedure>(copyfile from to . options)</procedure> Copies {{FROM}} file to {{TO}} file using the OS X {{copyfile(3)}} API, preserving HFS+ metadata as specified in copyfile {{OPTIONS}}. Always returns a true value, indicating success; failure will raise an error. In the current implementation, both {{FROM}} and {{TO}} must be filenames; ports are not accepted. If the {{#:check}} option is given, {{copyfile}} will determine which metadata would be copied from the source, without copying it. It returns zero if there is no corresponding metadata, and a positive value if there is metadata to copy. Either way, the return value is true, indicating success. If {{#:pack}} is given, {{copyfile}} serializes the desired metadata to an AppleDouble file named by the {{TO}} argument. {{#:unpack}} is the opposite of {{#:pack}}. This AppleDouble file is the same format as that produced when writing a file to a non-HFS+ filesystem, such as across a network to NFS or Samba. Because an AppleDouble file is always created when packing, even if there is no metadata to copy, you may wish to use {{#:check}} first to avoid this. ===== copyfile options Refer to the [[http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/copyfile.3.html|copyfile(3) manpage]] for details. These options specify ''which'' data to copy: <nowiki> <table> <tr><td>#:acls</td><td>COPYFILE_ACL</td><td>Copy ACLs</td></tr> <tr><td>#:stat</td><td>COPYFILE_STAT</td><td>Copy POSIX stat(2) items</td></tr> <tr><td>#:extended-attributes</td><td>COPYFILE_XATTR</td><td>Copy HFS+ extended attributes</td></tr> <tr><td>#:data</td><td>COPYFILE_DATA</td><td>Copy file data</td></tr> <tr><td>#:security</td><td>COPYFILE_SECURITY</td><td>Equivalent to #:acls #:stat</td></tr> <tr><td>#:metadata</td><td>COPYFILE_METADATA</td><td>Equivalent to #:extended-attributes #:security</td></tr> <tr><td>#:all</td><td>COPYFILE_ALL</td><td>Equivalent to #:metadata #:data</td></tr> </table> </nowiki> These options are flags which affect the copy operation: <nowiki> <table> <tr><td>#:check</td><td>COPYFILE_CHECK</td><td>Dry-run; determine which metadata would be copied</td></tr> <tr><td>#:pack</td><td>COPYFILE_PACK</td><td>Pack metadata in FROM to TO in AppleDouble format</td></tr> <tr><td>#:unpack</td><td>COPYFILE_UNPACK</td><td>Apply packed metadata in FROM to TO</td></tr> <tr><td>#:exclusive</td><td>COPYFILE_EXCL</td><td>Raise error if TO already exists</td></tr> <tr><td>#:no-follow-source</td><td>COPYFILE_NOFOLLOW_SRC</td><td>Do not follow symlink on FROM</td></tr> <tr><td>#:no-follow-dest</td><td>COPYFILE_NOFOLLOW_DST</td><td>Do not follow symlink on TO</td></tr> <tr><td>#:no-follow</td><td>COPYFILE_NOFOLLOW</td><td>Equivalent to #:no-follow-source #:no-follow-dest</td></tr> <tr><td>#:move</td><td>COPYFILE_MOVE</td><td>Unlink FROM after the copy</td></tr> <tr><td>#:unlink</td><td>COPYFILE_UNLINK</td><td>Unlink TO prior to copy</td></tr> </table> </nowiki> ===== copyfile deficiencies {{copyfile(3)}} is present on OS X 10.4, but not officially supported. On 10.4, we recommend using {{copyfile}} only to pack and unpack metadata to and from AppleDouble format. Certain options do not work properly: {{#:move}} has no effect; {{#:no-follow}} has no effect during a pack/unpack; #:data will fail with an error (and may even cause a segfault). There may be other deficiencies. === Utilities ==== get-extended-attributes <procedure>(get-extended-attributes file . options)</procedure> Returns an alist mapping attribute names (symbols) to values (strings). (get-extended-attributes "examples.scm") ;=> ((com.apple.FinderInfo . "TEXTEMAx") (com.apple.ResourceFork . "courtesy of Chicken") (org.callcc . "courtesy of Chicken")) ==== clear-extended-attributes! <procedure>(clear-extended-attributes! file . options)</procedure> Remove all extended attributes from {{FILE}}. ==== copyfile-check <procedure>(copyfile-check from . options)</procedure> Determines if any metadata is present in {{FROM}} using the {{#:check}} option to {{copyfile}}. Returns a list of symbols denoting metadata types that are present, from the following possibilities: <nowiki> <table> <tr><td>acls</td><td>COPYFILE_ACL</td><td>ACLs</td></tr> <tr><td>stat</td><td>COPYFILE_STAT</td><td>POSIX stat(2) data</td></tr> <tr><td>extended-attributes</td><td>COPYFILE_XATTR</td><td>Extended attributes</tr> </table> </nowiki> Note: another way to check merely for the presence of metadata is to use the {{#:check}} option to copyfile. A positive value means present, a zero value means not present. Example: #;> (copyfile-check "foo.txt" #:metadata) (acls stat extended-attributes) #;> (copyfile-check "foo.txt" #:extended-attributes) (extended-attributes) #;> (copyfile-check "bar.txt" #:metadata) () #;> (> (copyfile "foo.txt" #f #:check #:metadata) 0) #t #;> (> (copyfile "bar.txt" #f #:check #:metadata) 0) #f ==== pack-appledouble <procedure>(pack-appledouble from to . options)</procedure> Serialize all HFS+ metadata (extended attributes, ACLs, stat(2) data) in {{FROM}} to AppleDouble file {{TO}}. Returns false when no metadata was present (and does not write a file) or true if metadata was present (and a file is written). May also throw a file error. Extra options are passed into {{copyfile}}; relevant ones might be {{#:exclusive}}, {{#:move}} and {{#:no-follow}}, although {{#:move}} and {{#:no-follow}} do not work correctly under Tiger. ==== unpack-appledouble <procedure>(unpack-appledouble from to . options)</procedure> Unserialize all HFS+ metadata in AppleDouble file {{FROM}} to {{TO}}. Always returns true, or throws an error on I/O error. === Errors If the system API returns an unrecoverable error, a Scheme error will be raised. The exception is of type {{(exn file hfs+)}}. === Notes ==== Resource forks Special care is required when writing resource fork data. OS X will ''not'' truncate an existing resource fork if you write a shorter value, so you must remove the resource fork prior to writing. Incorrect example: $ echo -n "courtesy of the command-line" > examples.scm/rsrc $ csi -q -R hfs+ <<EOF (set-extended-attribute! "examples.scm" 'com.apple.ResourceFork "courtesy of Chicken") EOF $ cat examples.scm/rsrc ; echo courtesy of Chickenmand-line Correct example: $ echo -n "courtesy of the command-line" > examples.scm/rsrc $ csi -q -R hfs+ <<EOF (remove-extended-attribute! "examples.scm" 'com.apple.ResourceFork #:silent) (set-extended-attribute! "examples.scm" 'com.apple.ResourceFork "courtesy of Chicken" #:create) EOF $ cat examples.scm/rsrc ; echo courtesy of Chicken === Author Jim Ursetto === Version history * 0.3 Add copyfile interface * 0.2 Add #:silent option to remove, clear-extended-attributes! * 0.1 Initial release === License BSD. The Apple header [[http://www.opensource.apple.com/source/Libc/Libc-391.5.18/darwin/copyfile.h|copyfile.h]] is not present on Tiger, so it is included in the egg. The header is under the [[http://www.opensource.apple.com/apsl/|Apple Public Source License]]. Description of your changes:

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