# versionvfs.tcl --
 #
 #        A versioning virtual filesystem.
 #
 #        Similar to historical versioning filesystems, each edited version of a file is saved separately;
 #        each version file is tagged with a timestamp, and optional project tags.
 #        A deleted file is represented by a new zero-length file with timestamp and a tag reading "deleted".
 #        By default only the latest version is visible.  If the latest version is marked deleted, it is invisible.
 #        Directories are versioned and tagged in the same way as files.
 #
 #
 # Written by Stephen Huntley (stephen.huntley@alum.mit.edu)
 #
 # Install: This code requires that the template vfs (http://wiki.tcl.tk/11938) procedures have already
 # been sourced into the interpreter.
 #
 # Usage: Mount <existing directory> ?-keep <number>? ?-project <project name list>? ?-time <time>? <virtual versioning directory>
 #
 # Options:
 #
 # -keep
 #        maximum number of previous file versions to keep.
 #
 # -project
 #        a list of one or more identifying tags to associate with all files created or edited.
 #        If a file has project tags but none of them is included in the project
 #        name list, it will be invisible.
 #
 #        The project name list is stored in namespace variable $project($root).
 #        This variable can be edited while volume is still mounted, changes will
 #        will be taken into account dynamically.
 #
 #        In cases where several file versions each have multiple tags that match in the 
 #        list in $project($root), the version with the greatest number of matches will be visible.
 #
 #        Deleted files are marked with the tag "deleted".  If this value is in the project
 #        name list, then deleted files will become visible again.
 #
 #        If a file version exists without any project tags, it will be treated as the default, and
 #        will be visible even if tags are specified in $project($root), if no other version has matching tags.
 #
 # -time
 #        A timestamp in the form of [clock seconds], or a string understandable by [clock scan].
 #        Versions of files as they existed at the given time will be visible, rather than the
 #        default latest version.  
 #
 #        Value is stored in the namespace variable $time($root) and can be edited
 #        with volume still mounted.  Visible file versions will change to reflect edited value.

 package require vfs 1

 namespace eval ::vfs::template::version {}

 proc ::vfs::template::version::Mount {args} {
        eval [info body ::vfs::template::Mount]
 }

 namespace eval ::vfs::template::version {

 proc MountProcedure {args} {
        foreach templateProc "Mount Unmount CloseTrace handler" {
                set infoArgs [info args ::vfs::template::$templateProc]
                set infoBody [info body ::vfs::template::$templateProc]
                proc $templateProc $infoArgs $infoBody
        }

        set to [file normalize [lindex $args end]]
        set args [lrange $args 0 end-1]
        set path [file normalize [lindex $args 0]]
        set args [lrange $args 1 end]

        if [info exists ::vfs::_unmountCmd($to)] {::vfs::unmount $to}

        set argsLength [llength $args]
        for {set i 0} {$i < $argsLength} {incr i} {
                switch -- [lindex $args $i] {
                        -keep {
                                set keep [lindex $args [incr i]]
                                if ![string is digit -strict $keep] {continue}
                                set ::vfs::template::version::keep($to) $keep
                        }
                        -project {
                                set project [lindex $args [incr i]]
                                lappend ::vfs::template::version::project($to) $project
                        }
                        -time {
                                set time [lindex $args [incr i]]
                                SetTime $time
                                set ::vfs::template::version::time($to) $time
                        }
                }
        }

        if [catch {glob -directory $path -type {f hidden} .&dir*}] {
                CreateDirectory $path $to {} {}
        }

        lappend pathto $path
        lappend pathto $to
        return $pathto
 }

 proc UnmountProcedure {path to} {
        array unset ::vfs::template::version::keep $to
        array unset ::vfs::template::version::project $to
        array unset ::vfs::template::version::time $to
        return
 }

 proc Access {path root relative actualpath mode} {
        set fileName [VAcquireFile $path $root $relative $actualpath]
        set modeString [::vfs::accessMode $mode]
        if {$modeString == "F"} {
                if ![string first .&dir [file tail $fileName]] {error "no such file or directory"}
                if [file exists $fileName] {return}
                error "no such file or directory"
        }
        set modeString [split $modeString {}]
        set fileString {}
        if {[string equal $modeString "R"] && [file readable $fileName]} {return}
        if {[string equal $modeString "W"] && [file writable $fileName]} {return}
        if {[string equal $modeString "X"] && [file executable $fileName]} {return}
        file stat $fileName stat
        foreach { mask pairs } {
                00400 { 00400 r }
                00200 { 00200 w }
                04100 { 04100 s 04000 S 00100 x }
                00040 { 00040 r }
                00020 { 00020 w }
                02010 { 02010 s 02000 S 00010 x }
                00004 { 00004 r }
                00002 { 00002 w }
                01001 { 01001 t 01000 T 00001 x }
            } {
                set value [expr $stat(mode) & $mask]
                set bit -
                foreach { x b } $pairs {
                    if { $value == $x } {
                        set bit $b
                    }
                }
                append bitString $bit
      }
        set readable [regexp -all "r" $bitString]
        set writable [regexp -all "w" $bitString]
        set executable [regexp -all "x" $bitString]
        foreach {mode count} "R $readable W $writable X $executable" {
                if {([string first $mode $modeString] > -1) && !$count} {error "$mode access not allowed"}
        }
        if [string equal $modeString "X W"] {
                if {($writable == 3) && ($executable == 3)} {
                        return
                } elseif [file writable $fileName] {
                        if {[regexp -all "wx" $bitString] == $writable} {
                                return
                        } elseif [file executable $fileName] {
                                return
                        }
                }
        }
        if [string equal $modeString "R W"] {
                if {($writable == 3) && ($readable == 3)} {
                        return
                } elseif [file writable $fileName] {
                        if {[regexp -all "rw" $bitString] == $writable} {
                                return
                        } elseif [file readable $fileName] {
                                return
                        }
                }
        }
        if [string equal $modeString "R X"] {
                if {($readable == 3) && ($executable == 3)} {
                        return
                } elseif [file executable $fileName] {
                        if {[regexp -all {r[w-]x} $bitString] == $executable} {
                                return
                        } elseif [file readable $fileName] {
                                return
                        }
                }
        }

        foreach mS $modeString {
                set errorMessage "not [string map {R readable W writable X executable} $mS]"
                if {[lsearch $fileString $mS] == -1} {error $errorMessage}
        }
 }

 proc CreateDirectory {path root relative actualpath} {
        file mkdir [file join $path $relative]
        set fileName [VFileNameEncode [file join $path $relative]]
        set fileName [file join $fileName .&dir[file tail $fileName]]\;[VCreateTag $root]
        close [open $fileName w]
        catch {file attributes $fileName -hidden 1}
 }

 proc DeleteFile {path root relative actualpath} {
        set fileName [VFileNameEncode [file join $path $relative]]\;[VCreateTag $root]
        set fileName [split $fileName \;]
        set fileName [linsert $fileName 2 "deleted"]
        set fileName [join $fileName \;]
        close [open $fileName w]
 }

 proc FileAttributes {path root relative actualpath} {
        set fileName [VAcquireFile $path $root $relative $actualpath]
        array set attributes [file attributes $fileName]
        array unset attributes -longname
        array unset attributes -shortname
        return [array get attributes]
 }

 proc FileAttributesSet {path root relative actualpath attribute value} {
        if [info exists ::vfs::template::version::time($root)] {
                set existingTime $::vfs::template::version::time($root)
                set ::vfs::template::version::time($root) [clock seconds]
                set fileName [VAcquireFile $path $root $relative $actualpath]
                set ::vfs::template::version::time($root) $existingTime
        } else {
                set fileName [VAcquireFile $path $root $relative $actualpath]
        }
        file attributes $fileName $attribute $value
 }

 proc MatchInDirectory {path root relative actualpath pattern types} {
        if [::vfs::matchDirectories $types] {lappend typeString d}
        if [::vfs::matchFiles $types] {lappend typeString f}
        
        set globList [glob -directory [file join $path $relative] -nocomplain -types $typeString *]
        if [catch {::vfs::filesystem info $path}] {append globList " [glob -directory [file join $path $relative] -nocomplain -types "$typeString hidden" *]"}

        set newGlobList {}
        set acquireAttempts {}
        foreach gL $globList {
                if [file isdirectory $gL] {
                        set acquiredFile [VAcquireFile $path $root [list [file join $relative [file tail $gL]]] $actualpath]
                        if ![string equal $acquiredFile $gL] {continue}
                } else {
                        if ![string first .&dir [file tail $gL]] {continue}
                        set gL [VFileNameDecode $gL]
                        if {[lsearch $acquireAttempts $gL] > -1} {continue}
                        lappend acquireAttempts $gL
                        set acquiredFile [VAcquireFile $path $root [list [file join $relative [file tail $gL]]] $actualpath]
                        if [string equal $acquiredFile $gL] {continue}
                }
                set gL [eval file join \$root [lrange [file split $gL] [llength [file split $path]] end]]
                if [string match $pattern [file tail $gL]] {lappend newGlobList $gL}
        }
        return [lsort -unique $newGlobList]
 }

 proc Open {path root relative actualpath mode permissions} {

        if [catch {package present md5 2}] {package forget md5 ; package require md5 2}
        set fileName [VAcquireFile $path $root $relative $actualpath]
        if {$mode == "r"} {return [open $fileName]}
        set md5 {}

        if {$fileName == [file join $path $relative]} {
                set fileName [VFileNameEncode [file join $path $relative]]\;[VCreateTag $root]
                close [open $fileName $mode]
                catch {file attributes $fileName -permissions $permissions}
                set channelID [vfs::memchan]
                set ::vfs::template::version::filestats($channelID) "filename [list $fileName] -permissions $permissions md5 [list $md5]"
                return $channelID
        }

        set f [open $fileName r]
        fconfigure $f -translation binary
        set md5 [::md5::md5 -hex -- [read $f]]
        close $f
        set filed [vfs::memchan]
        if {[string index $mode 0] == "a"} {
                set f [open $fileName r]
                fconfigure $f -translation binary
                fconfigure $filed -translation binary
                fcopy $f $filed
                close $f
                seek $filed 0
        }
        file stat $fileName fileStats
        array set fileStats [file attributes $fileName]
        set fileStats(md5) $md5
        set ::vfs::template::version::filestats($filed) [array get fileStats]
        return $filed
 }

 proc Close {channelID path root relative actualpath mode} {
 # Do not close the channel in the close callback!
 # It will crash Tcl!  Honest!
 # The core will close the channel after you've taken what info you need from it.

 #        close $channelID
        if {$mode == "r"} {return}
        if [catch {package present md5 2}] {package forget md5 ; package require md5 2}
        array set fileStats $::vfs::template::version::filestats($channelID)

        unset ::vfs::template::version::filestats($channelID)

        if [string equal $fileStats(md5) {}] {
                file delete $fileStats(filename)
        }
        set cr \\x0D
        set lf \\x0A
        set crlf \\x0D\\x0A
        set outMode [lindex [fconfigure $channelID -translation] end]
        seek $channelID 0
        fconfigure $channelID -translation binary
        set md5 [::md5::md5 -hex -- [read $channelID]]
        if [string equal -nocase $md5 $fileStats(md5)] {return}

        set fileName [VFileNameEncode [file join $path $relative]]\;[VCreateTag $root]
        set f [open $fileName w]
        fconfigure $f -translation binary
        seek $channelID 0
        fcopy $channelID $f
        close $f
        catch {file attributes $fileName -readonly 0}
        catch {file attributes $fileName -permissions rw-rw-rw-}
        catch {file attributes $fileName -owner $fileStats(uid)}
        catch {file attributes $fileName -group $fileStats(gid)}
        catch {file atime $fileName $fileStats(atime)}

        foreach attr [array names fileStats] {
                if [string first "-" $attr] {continue}
                if ![string first "-permissions" $attr] {continue}
                if ![string first "-readonly" $attr] {continue}
                catch {file attributes $fileName $attr $fileStats($attr)}
        }
        catch {file attributes $fileName -permissions $fileStats(mode)}
        catch {file attributes $fileName -readonly $fileStats(-readonly)}

        return
 }

 proc RemoveDirectory {path root relative actualpath} {
        set fileName [VFileNameEncode [file join $path $relative]]
        set fileName [file join $fileName .&dir[file tail $fileName]]\;[VCreateTag $root]

        set fileName [split $fileName \;]
        set fileName [linsert $fileName 2 "deleted"]
        set fileName [join $fileName \;]
        close [open $fileName w]
        catch {file attributes $fileName -hidden 1}
 }

 proc Stat {path root relative actualpath} {
        set fileName [VAcquireFile $path $root $relative $actualpath]
        file stat $fileName fs
        return [array get fs]
 }

 proc Utime {path root relative actualpath atime mtime} {
        if [info exists ::vfs::template::version::time($root)] {
                set existingTime $::vfs::template::version::time($root)
                set ::vfs::template::version::time($root) [clock seconds]
                set fileName [VAcquireFile $path $root $relative $actualpath]
                set ::vfs::template::version::time($root) $existingTime
        } else {
                set fileName [VAcquireFile $path $root $relative $actualpath]
        }

        file atime $fileName $atime
        file mtime $fileName $mtime
 }

 proc SetTime {time} {
        if ![string is digit -strict $time] {catch {set time [clock scan $time]}}
        if ![string is digit -strict $time] {error "invalid time value."}
        set time [string range $time 0 [expr [string length [clock seconds]] - 1]]
        set time "[clock scan [clock format $time -format %Y%m%dT%H%M%S -gmt 1]]000"
 }

 proc VAcquireFile {path root relative actualpath} {
        set fileName [VFileNameEncode [file join $path $relative]]
        if [file isdirectory [file join $path $relative]] {
                set fileName [file join $fileName .&dir[file tail $fileName]]
                set relative [file join $relative .&dir[file tail $relative]]
        }
        set versions [glob -path $fileName -nocomplain -types f "\;*"]
        if [catch {::vfs::filesystem info $path}] {append versions " [glob -path $fileName -nocomplain -types "f hidden" "\;*"]"}

        set versions [string trim $versions]
        if {$versions == {}} {return [file join $path $relative]}

        set checkProject 0
        if [info exists ::vfs::template::version::project($root)] {
                set projects [string map {; &s} [string map {& &a} $::vfs::template::version::project($root)]]
                set checkProject 1
        }
        foreach ver $versions {
                set ver $root/[file tail $ver]
                lappend versionFiles $ver
                if !$checkProject {continue}
                foreach project $projects {
                        if {[lsearch [lrange [split $ver \;] 1 end] $project] > -1} {lappend projectFiles $ver}
                }
        }
        unset versions

        if ![catch {if {[llength $projectFiles] <= $::vfs::template::version::keep($root)} {error}}] {
                set keep $::vfs::template::version::keep($root)
                set projectFiles [lsort -decreasing -dictionary $projectFiles]
                set fileNumber [llength $projectFiles]
                for {set i [incr fileNumber -1]} {$i >= 0} {incr i -1} {
                        if {[llength $projectFiles] <= $keep} {break}
                        if ![catch {file delete $path/[lindex $projectFiles $i]}] {set projectFiles [lreplace $projectFiles $i $i]}
                }
        }

        set fileName [file tail [lindex [lsort -command VersionSort $versionFiles] 0]]

        if !$checkProject {
                if {[lindex [split $fileName \;] 2] == "deleted"} {return [file join $path $relative]}
        }

        if $checkProject {
                if {([lindex [split $fileName \;] 2] == "deleted") && ([lsearch $projects "deleted"] == -1)} {return [file join $path $relative]}
                set projectMember 0
                set tags [lrange [split $fileName \;] 1 end]
                if {[lindex $tags 1] == "deleted"} {set tags [lreplace $tags 1 1]}
                foreach project $projects {
                                if {[lsearch $tags $project] > -1} {set projectMember 1}
                }
                set projectLength [llength $tags]
                if {($projectLength > 1) && !$projectMember} {return [file join $path $relative]}
        }
        if ![string first .&dir [file tail $relative]] {
                set fileName [file join $path [file dirname $relative]]
                return [file normalize $fileName]
        }
        return [file join [file dirname [file join $path $relative]] $fileName]
 }

 proc VCreateTag {root} {
        set tag [clock scan [clock format [clock seconds] -format %Y%m%dT%H%M%S -gmt 1]][string range [clock clicks -milliseconds] end-2 end]
        if [info exists ::vfs::template::version::project($root)] {
                set projects [string map {; &s} [string map {& &a} $::vfs::template::version::project($root)]]
                set projectTag [join $projects \;]
                set tag [join "$tag $projectTag" \;]
        }
        return $tag
 }

 proc VersionSort {element1 element2} {
        set root [file dirname $element1]
        set element1 [file tail $element1]
        set element2 [file tail $element2]
        if [string equal $element1 $element2] {return 0}
        set sorted [lsort -dictionary -decreasing "$element1 $element2"]
        if {[lindex $sorted 0] == $element1} {set returnValue -1}
        if {[lindex $sorted 0] == $element2} {set returnValue 1}

        set time1 [lindex [split $element1 \;] 1]
        set time2 [lindex [split $element2 \;] 1]
        set time $time1
        if {$time2 > $time1} {set time $time2}
        if [info exists ::vfs::template::version::time($root)] {
                set returnValue -1
                set time $::vfs::template::version::time($root)
                if {!([string is digit -strict $time] && ([string length $time] == [string length $time1]))} {
                        set time [SetTime $::vfs::template::version::time($root)]
                }

                if {$time1 > $time} {set time1 [expr $time2 - 1]}
                if {($time2 <= $time) && ($time2 > $time1)} {set returnValue 1}
        }

        if [info exists ::vfs::template::version::project($root)] {
                set projects [string map {; &s} [string map {& &a} $::vfs::template::version::project($root)]]
                set project1 0
                set project2 0
                foreach project [lsort -unique $projects] {
                        set sumproject1 [lsearch [lrange [split $element1 \;] 1 end] $project]
                        set sumproject2 [lsearch [lrange [split $element2 \;] 1 end] $project]
                        incr sumproject1 ; incr sumproject2
                        if $sumproject1 {incr project1}
                        if $sumproject2 {incr project2}
                }
                if {$project1 > $project2} {set project1 1 ; set project2 0}
                if {$project1 < $project2} {set project1 0 ; set project2 1}

                set tagEnd1 [lindex [split $element1 \;] 2]
                if {$tagEnd1 == "deleted"} {set tagEnd1 [lindex [split $element1 \;] 3]}
                set tagEnd2 [lindex [split $element2 \;] 2]
                if {$tagEnd2 == "deleted"} {set tagEnd2 [lindex [split $element2 \;] 3]}
                if {($tagEnd1 == {}) && !($tagEnd2 == {})} {set returnValue -1}
                if {!($tagEnd1 == {}) && ($tagEnd2 == {})} {set returnValue 1}

                if {$project2 && !$project1 && ($time2 <= $time)} {set returnValue 1}
                if {$project1 && !$project2 && ($time1 <= $time)} {set returnValue -1}
        }
        return $returnValue
 }

 proc VFileNameEncode {filename} {
        set filename [file dirname $filename]/[string map {& &a} [file tail $filename]]
        set filename [file dirname $filename]/[string map {; &s} [file tail $filename]]
 }

 proc VFileNameDecode {filename} {
        set filename [file dirname $filename]/[lindex [split [file tail $filename] \;] 0]
        set filename [file dirname $filename]/[string map {&s ;} [file tail $filename]]
        set filename [file dirname $filename]/[string map {&a &} [file tail $filename]]
 }

 }
 # end namespace eval vfs::template::version

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