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Diffstat (limited to 'library/tm.tcl')
| -rw-r--r-- | library/tm.tcl | 380 |
1 files changed, 380 insertions, 0 deletions
diff --git a/library/tm.tcl b/library/tm.tcl new file mode 100644 index 0000000..c5db437 --- /dev/null +++ b/library/tm.tcl @@ -0,0 +1,380 @@ +# -*- tcl -*- +# +# Searching for Tcl Modules. Defines a procedure, declares it as the +# primary command for finding packages, however also uses the former +# 'package unknown' command as a fallback. +# +# Locates all possible packages in a directory via a less restricted +# glob. The targeted directory is derived from the name of the +# requested package. I.e. the TM scan will look only at directories +# which can contain the requested package. It will register all +# packages it found in the directory so that future requests have a +# higher chance of being fulfilled by the ifneeded database without +# having to come to us again. +# +# We do not remember where we have been and simply rescan targeted +# directories when invoked again. The reasoning is this: +# +# - The only way we get back to the same directory is if someone is +# trying to [package require] something that wasn't there on the +# first scan. +# +# Either +# 1) It is there now: If we rescan, you get it; if not you don't. +# +# This covers the possibility that the application asked for a +# package late, and the package was actually added to the +# installation after the application was started. It shoukld +# still be able to find it. +# +# 2) It still is not there: Either way, you don't get it, but the +# rescan takes time. This is however an error case and we dont't +# care that much about it +# +# 3) It was there the first time; but for some reason a "package +# forget" has been run, and "package" doesn't know about it +# anymore. +# +# This can be an indication that the application wishes to reload +# some functionality. And should work as well. +# +# Note that this also strikes a balance between doing a glob targeting +# a single package, and thus most likely requiring multiple globs of +# the same directory when the application is asking for many packages, +# and trying to glob for _everything_ in all subdirectories when +# looking for a package, which comes with a heavy startup cost. +# +# We scan for regular packages only if no satisfying module was found. + +namespace eval ::tcl::tm { + # Default paths. None yet. + + variable paths {} + + # The regex pattern a file name has to match to make it a Tcl Module. + + set pkgpattern {^([_[:alpha:]][:_[:alnum:]]*)-([[:digit:]].*)[.]tm$} + + # Export the public API + + namespace export path + namespace ensemble create -command path -subcommand {add remove list} +} + +# ::tcl::tm::path implementations -- +# +# Public API to the module path. See specification. +# +# Arguments +# cmd - The subcommand to execute +# args - The paths to add/remove. Must not appear querying the +# path with 'list'. +# +# Results +# No result for subcommands 'add' and 'remove'. A list of paths +# for 'list'. +# +# Sideeffects +# The subcommands 'add' and 'remove' manipulate the list of +# paths to search for Tcl Modules. The subcommand 'list' has no +# sideeffects. + +proc ::tcl::tm::add {path args} { + # PART OF THE ::tcl::tm::path ENSEMBLE + # + # The path is added at the head to the list of module paths. + # + # The command enforces the restriction that no path may be an + # ancestor directory of any other path on the list. If the new + # path violates this restriction an error wil be raised. + # + # If the path is already present as is no error will be raised and + # no action will be taken. + + variable paths + + # We use a copy of the path as source during validation, and + # extend it as well. Because we not only have to detect if the new + # paths are bogus with respect to the existing paths, but also + # between themselves. Otherwise we can still add bogus paths, by + # specifying them in a single call. This makes the use of the new + # paths simpler as well, a trivial assignment of the collected + # paths to the official state var. + + set newpaths $paths + foreach p [linsert $args 0 $path] { + if {$p in $newpaths} { + # Ignore a path already on the list. + continue + } + + # Search for paths which are subdirectories of the new one. If + # there are any then the new path violates the restriction + # about ancestors. + + set pos [lsearch -glob $newpaths ${p}/*] + # Cannot use "in", we need the position for the message. + if {$pos >= 0} { + return -code error \ + "$p is ancestor of existing module path [lindex $newpaths $pos]." + } + + # Now look for existing paths which are ancestors of the new + # one. This reverse question forces us to loop over the + # existing paths, as each element is the pattern, not the new + # path :( + + foreach ep $newpaths { + if {[string match ${ep}/* $p]} { + return -code error \ + "$p is subdirectory of existing module path $ep." + } + } + + set newpaths [linsert $newpaths 0 $p] + } + + # The validation of the input is complete and successful, and + # everything in newpaths is either an old path, or added. We can + # now extend the official list of paths, a simple assignment is + # sufficient. + + set paths $newpaths + return +} + +proc ::tcl::tm::remove {path args} { + # PART OF THE ::tcl::tm::path ENSEMBLE + # + # Removes the path from the list of module paths. The command is + # silently ignored if the path is not on the list. + + variable paths + + foreach p [linsert $args 0 $path] { + set pos [lsearch -exact $paths $p] + if {$pos >= 0} { + set paths [lreplace $paths $pos $pos] + } + } +} + +proc ::tcl::tm::list {} { + # PART OF THE ::tcl::tm::path ENSEMBLE + + variable paths + return $paths +} + +# ::tcl::tm::UnknownHandler -- +# +# Unknown handler for Tcl Modules, i.e. packages in module form. +# +# Arguments +# original - Original [package unknown] procedure. +# name - Name of desired package. +# version - Version of desired package. Can be the +# empty string. +# exact - Either -exact or ommitted. +# +# Name, version, and exact are used to determine +# satisfaction. The original is called iff no satisfaction was +# achieved. The name is also used to compute the directory to +# target in the search. +# +# Results +# None. +# +# Sideeffects +# May populate the package ifneeded database with additional +# provide scripts. + +proc ::tcl::tm::UnknownHandler {original name args} { + # Import the list of paths to search for packages in module form. + # Import the pattern used to check package names in detail. + + variable paths + variable pkgpattern + + # Without paths to search we can do nothing. (Except falling back + # to the regular search). + + if {[llength $paths]} { + set pkgpath [string map {:: /} $name] + set pkgroot [file dirname $pkgpath] + if {$pkgroot eq "."} { + set pkgroot "" + } + + # We don't remember a copy of the paths while looping. Tcl + # Modules are unable to change the list while we are searching + # for them. This also simplifies the loop, as we cannot get + # additional directories while iterating over the list. A + # simple foreach is sufficient. + + set satisfied 0 + foreach path $paths { + if {![interp issafe] && ![file exists $path]} { + continue + } + set currentsearchpath [file join $path $pkgroot] + if {![interp issafe] && ![file exists $currentsearchpath]} { + continue + } + set strip [llength [file split $path]] + + # We can't use glob in safe interps, so enclose the following + # in a catch statement, where we get the module files out + # of the subdirectories. In other words, Tcl Modules are + # not-functional in such an interpreter. This is the same + # as for the command "tclPkgUnknown", i.e. the search for + # regular packages. + + catch { + # We always look for _all_ possible modules in the current + # path, to get the max result out of the glob. + + foreach file [glob -nocomplain -directory $currentsearchpath *.tm] { + set pkgfilename [join [lrange [file split $file] $strip end] ::] + + if {![regexp -- $pkgpattern $pkgfilename --> pkgname pkgversion]} { + # Ignore everything not matching our pattern + # for package names. + continue + } + if {[catch {package vcompare $pkgversion 0}]} { + # Ignore everything where the version part is + # not acceptable to "package vcompare". + continue + } + + # We have found a candidate, generate a "provide + # script" for it, and remember it. Note that we + # are using ::list to do this; locally [list] + # means something else without the namespace + # specifier. + + # NOTE. When making changes to the format of the + # provide command generated below CHECK that the + # 'LOCATE' procedure in core file + # 'platform/shell.tcl' still understands it, or, + # if not, update its implementation appropriately. + # + # Right now LOCATE's implementation assumes that + # the path of the package file is the last element + # in the list. + + package ifneeded $pkgname $pkgversion \ + "[::list package provide $pkgname $pkgversion];[::list source -encoding utf-8 $file]" + + # We abort in this unknown handler only if we got + # a satisfying candidate for the requested + # package. Otherwise we still have to fallback to + # the regular package search to complete the + # processing. + + if { + ($pkgname eq $name) && + [package vsatisfies $pkgversion {*}$args] + } then { + set satisfied 1 + # We do not abort the loop, and keep adding + # provide scripts for every candidate in the + # directory, just remember to not fall back to + # the regular search anymore. + } + } + } + } + + if {$satisfied} { + return + } + } + + # Fallback to previous command, if existing. See comment above + # about ::list... + + if {[llength $original]} { + uplevel 1 $original [::linsert $args 0 $name] + } +} + +# ::tcl::tm::Defaults -- +# +# Determines the default search paths. +# +# Arguments +# None +# +# Results +# None. +# +# Sideeffects +# May add paths to the list of defaults. + +proc ::tcl::tm::Defaults {} { + global env tcl_platform + + lassign [split [info tclversion] .] major minor + set exe [file normalize [info nameofexecutable]] + + # Note that we're using [::list], not [list] because [list] means + # something other than [::list] in this namespace. + roots [::list \ + [file dirname [info library]] \ + [file join [file dirname [file dirname $exe]] lib] \ + ] + + if {$tcl_platform(platform) eq "windows"} { + set sep ";" + } else { + set sep ":" + } + for {set n $minor} {$n >= 0} {incr n -1} { + foreach ev [::list \ + TCL${major}.${n}_TM_PATH \ + TCL${major}_${n}_TM_PATH \ + ] { + if {![info exists env($ev)]} continue + foreach p [split $env($ev) $sep] { + path add $p + } + } + } + return +} + +# ::tcl::tm::roots -- +# +# Public API to the module path. See specification. +# +# Arguments +# paths - List of 'root' paths to derive search paths from. +# +# Results +# No result. +# +# Sideeffects +# Calls 'path add' to paths to the list of module search paths. + +proc ::tcl::tm::roots {paths} { + foreach {major minor} [split [info tclversion] .] break + foreach pa $paths { + set p [file join $pa tcl$major] + for {set n $minor} {$n >= 0} {incr n -1} { + set px [file join $p ${major}.${n}] + if {![interp issafe]} { set px [file normalize $px] } + path add $px + } + set px [file join $p site-tcl] + if {![interp issafe]} { set px [file normalize $px] } + path add $px + } + return +} + +# Initialization. Set up the default paths, then insert the new +# handler into the chain. + +if {![interp issafe]} { ::tcl::tm::Defaults } |