Artifact 42309dffc262bd5856231c2ce9a2c052668b2fe2
File
tools/cvs2fossil/lib/c2f_pbreakacycle.tcl
part of check-in
[6d63634309]
- Tweaked log output a bit. Bugfixes: Forgot to propagate the border information into SplitRevisions, and a varname typo.
by
aku on
2007-11-24 04:19:15.
## -*- tcl -*-
# # ## ### ##### ######## ############# #####################
## Copyright (c) 2007 Andreas Kupries.
#
# This software is licensed as described in the file LICENSE, which
# you should have received as part of this distribution.
#
# This software consists of voluntary contributions made by many
# individuals. For exact contribution history, see the revision
# history and logs, available at http://fossil-scm.hwaci.com/fossil
# # ## ### ##### ######## ############# #####################
## Pass VIII. This is the final pass for breaking changeset dependency
## cycles. The two previous passes broke cycles covering revision and
## symbol changesets, respectively. This pass now breaks any remaining
## cycles each of which has to contain at least one revision and at
## least one symbol changeset.
# # ## ### ##### ######## ############# #####################
## Requirements
package require Tcl 8.4 ; # Required runtime.
package require snit ; # OO system.
package require struct::list ; # Higher order list operations.
package require vc::tools::misc ; # Min, max.
package require vc::tools::log ; # User feedback.
package require vc::tools::trouble ; # Error reporting.
package require vc::fossil::import::cvs::repository ; # Repository management.
package require vc::fossil::import::cvs::cyclebreaker ; # Breaking dependency cycles.
package require vc::fossil::import::cvs::state ; # State storage.
package require vc::fossil::import::cvs::project::rev ; # Project level changesets
# # ## ### ##### ######## ############# #####################
## Register the pass with the management
vc::fossil::import::cvs::pass define \
BreakAllCsetCycles \
{Break Remaining ChangeSet Dependency Cycles} \
::vc::fossil::import::cvs::pass::breakacycle
# # ## ### ##### ######## ############# #####################
##
snit::type ::vc::fossil::import::cvs::pass::breakacycle {
# # ## ### ##### ######## #############
## Public API
typemethod setup {} {
# Define the names and structure of the persistent state of
# this pass.
state reading csorder
return
}
typemethod load {} {
# Pass manager interface. Executed to load data computed by
# this pass into memory when this pass is skipped instead of
# executed.
return
}
typemethod run {} {
# Pass manager interface. Executed to perform the
# functionality of the pass.
cyclebreaker precmd [myproc BreakBackwardBranches]
cyclebreaker savecmd [myproc SaveOrder]
cyclebreaker breakcmd [myproc BreakCycle]
state transaction {
LoadCommitOrder
cyclebreaker run break-all [myproc Changesets]
}
repository printcsetstatistics
return
}
typemethod discard {} {
# Pass manager interface. Executed for all passes after the
# run passes, to remove all data of this pass from the state,
# as being out of date.
return
}
# # ## ### ##### ######## #############
## Internal methods
proc Changesets {} { project::rev all }
proc LoadCommitOrder {} {
::variable mycset
state transaction {
foreach {cid pos} [state run { SELECT cid, pos FROM csorder }] {
set cset [project::rev of $cid]
$cset setpos $pos
set mycset($pos) $cset
}
# Remove the order information now that we have it in
# memory, so that we can save it once more, for all
# changesets, while breaking the remaining cycles.
state run { DELETE FROM csorder }
}
return
}
# # ## ### ##### ######## #############
proc BreakBackwardBranches {graph} {
# We go over all branch changesets, i.e. the changesets
# created by the symbols which are translated as branches, and
# break any which are 'backward', which means that they have
# at least one incoming revision changeset which is committed
# after at least one of the outgoing revision changesets, per
# the order computed in pass 6. In "cvs2svn" this is called
# "retrograde".
# NOTE: We might be able to use our knowledge that we are
# looking at all changesets to create a sql which selects all
# the branch changesets from the state in one go instead of
# having to check each changeset separately. Consider this
# later, get the pass working first.
#
# NOTE 2: Might we even be able to select the backward branch
# changesets too ?
foreach cset [$graph nodes] {
if {![$cset isbranch]} continue
CheckAndBreakBackwardBranch $graph $cset
}
return
}
proc CheckAndBreakBackwardBranch {graph cset} {
while {[IsABackwardBranch $graph $cset]} {
log write 5 breakacycle "Breaking backward branch changeset <[$cset id]>"
# Knowing that the branch is backward we now look at the
# individual revisions in the changeset and determine
# which of them are responsible for the overlap. This
# allows us to split them into two sets, one of
# non-overlapping revisions, and of overlapping ones. Each
# induces a new changeset, and the second may still be
# backward and need further splitting. Hence the looping.
#
# The border used for the split is the minimal commit
# position among the minimal sucessor commit positions for
# the revisions in the changeset.
# Note that individual revisions may not have revision
# changesets are predecessors and/or successors, leaving
# the limits partially or completely undefined.
# limits : dict (revision -> list (max predecessor commit, min sucessor commit))
ComputeLimits $cset limits border
log write 6 breakacycle "Using commit position $border as border"
# Then we sort the file level items based on there they
# sit relative to the border into before and after the
# border.
SplitRevisions $limits $border normalrevisions backwardrevisions
set replacements [project::rev split $cset $normalrevisions $backwardrevisions]
cyclebreaker replace $graph $cset $replacements
# At last check that the normal frament is indeed not
# backward, and iterate over the possibly still backward
# second fragment.
struct::list assign $replacements normal backward
if {[IsABackwardBranch $graph $normal]} { trouble internal "The normal fragment is unexpectedly a backward branch" }
set cset $backward
}
return
}
proc IsABackwardBranch {dg cset} {
# A branch is "backward" if it has at least one incoming
# revision changeset which is committed after at least one of
# the outgoing revision changesets, per the order computed in
# pass 6.
# Rephrased, the maximal commit position found among the
# incoming revision changesets is larger than the minimal
# commit position found among the outgoing revision
# changesets. Assuming that we have both incoming and outgoing
# revision changesets.
# The helper "Positions" computes the set of commit positions
# for a set of changesets, which can be a mix of revision and
# symbol changesets.
set predecessors [Positions [$dg nodes -in $cset]]
set successors [Positions [$dg nodes -out $cset]]
return [expr {
[llength $predecessors] &&
[llength $successors] &&
([max $predecessors] >= [min $successors])
}]
}
proc Positions {changesets} {
# To compute the set of commit positions from the set of
# changesets we first map each changeset to its position (*)
# and then filter out the invalid responses (the empty string)
# returned by the symbol changesets.
#
# (*) This data was loaded into memory earlir in the pass, by
# LoadCommitOrder.
return [struct::list filter [struct::list map $changesets \
[myproc ToPosition]] \
[myproc ValidPosition]]
}
proc ToPosition {cset} { $cset pos }
proc ValidPosition {pos} { expr {$pos ne ""} }
proc ComputeLimits {cset lv bv} {
upvar 1 $lv thelimits $bv border
# Initialize the boundaries for all revisions.
array set limits {}
foreach revision [$cset revisions] {
set limits($revision) {0 {}}
}
# Compute and store the maximal predecessors per revision
foreach {revision csets} [$cset predecessormap] {
set s [Positions $csets]
if {![llength $s]} continue
set limits($revision) [lreplace $limits($revision) 0 0 [max $s]]
}
# Compute and store the minimal successors per revision
foreach {revision csets} [$cset successormap] {
set s [Positions $csets]
if {![llength $s]} continue
set limits($revision) [lreplace $limits($revision) 1 1 [min $s]]
}
# Check that the ordering at the file level is correct. We
# cannot have backward ordering per revision, or something is
# wrong.
foreach revision [array names limits] {
struct::list assign $limits($revision) maxp mins
# Handle min successor position "" as representing infinity
if {$mins eq ""} continue
if {$maxp < $mins} continue
trouble internal "Branch revision $revision is backward at file level ($maxp >= $mins)"
}
# Save the limits for the splitter, and compute the border at
# which to split as the minimum of all minimal successor
# positions.
set thelimits [array get limits]
set border [min [struct::list filter [struct::list map [Values $thelimits] \
[myproc MinSuccessorPosition]] \
[myproc ValidPosition]]]
return
}
proc Values {dict} {
set res {}
foreach {k v} $dict { lappend res $v }
return $res
}
proc MinSuccessorPosition {item} { lindex $item 1 }
proc SplitRevisions {limits border nv bv} {
upvar 1 $nv normalrevisions $bv backwardrevisions
set normalrevisions {}
set backwardrevisions {}
foreach {rev v} $limits {
struct::list assign $v maxp mins
if {$maxp >= $border} {
lappend backwardrevisions $rev
} else {
lappend normalrevisions $rev
}
}
if {![llength $normalrevisions]} { trouble internal "Set of normal revisions is empty" }
if {![llength $backwardrevisions]} { trouble internal "Set of backward revisions is empty" }
return
}
# # ## ### ##### ######## #############
proc SaveOrder {graph cset pos} {
}
# # ## ### ##### ######## #############
proc BreakCycle {graph} {
cyclebreaker break $graph
}
# # ## ### ##### ######## #############
typevariable mycset -array {} ; # Map from commit positions to the
# changeset (object ref) at that
# position.
# # ## ### ##### ######## #############
## Configuration
pragma -hasinstances no ; # singleton
pragma -hastypeinfo no ; # no introspection
pragma -hastypedestroy no ; # immortal
# # ## ### ##### ######## #############
}
namespace eval ::vc::fossil::import::cvs::pass {
namespace export breakacycle
namespace eval breakacycle {
namespace import ::vc::fossil::import::cvs::cyclebreaker
namespace import ::vc::fossil::import::cvs::repository
namespace import ::vc::fossil::import::cvs::state
namespace eval project {
namespace import ::vc::fossil::import::cvs::project::rev
}
namespace import ::vc::tools::misc::*
namespace import ::vc::tools::trouble
namespace import ::vc::tools::log
log register breakacycle
}
}
# # ## ### ##### ######## ############# #####################
## Ready
package provide vc::fossil::import::cvs::pass::breakacycle 1.0
return