awk/ref_prepare.awk

   1 #!/usr/bin/awk -f
   2
   3 # ref_prepare - TopGit awk utility script used by tg--awksome
   4 # Copyright (C) 2017 Kyle J. McKay <mackyle@gmail.com>
   5 # All rights reserved.
   6 # License GPLv2
   7
   8 # ref_prepare
   9 #
  10 # variable arguments (-v):
  11 #
  12 #   topbases  the full target topbases prefix (e.g. "refs/top-bases")
  13 #   headbase  the full heads prefix (default is based on topbases value)
  14 #   chkblob   if set spit out a verification line for this blob first
  15 #   depsblob  if true include 6th line ".topdeps" blob otherwise not
  16 #   msgblob   if true include 6th or 7th line ".topmsg" blob otherwise not
  17 #   refsfile  ref definitions are read from here and used to output hashes
  18 #   pckdrefs  ref table is in packed-refs format (ignored without refsfile)
  19 #   rmrf      if true run system rm on refsfile (after reading)
  20 #   topdeps   if in form <branch>:<hash> substitute <hash> for branch:.topdeps
  21 #   topmsg    if in form <branch>:<hash> substitute <hash> for branch:.topmsg
  22 #   teeout    if non-empty output lines are written here too
  23 #
  24 # if refsfile is non-empty, each line of the file it names must 2+ fields:
  25 #
  26 #   <full-ref-name> <full-hash-for-ref> <anything-else-on-line-ignored>
  27 #
  28 # Unless pckdrefs is true and then packed-refs format is expected instead
  29 #
  30 # if refsfile is non-empty, instead of outputting refnames, the name will be
  31 # looked up in the refsfile table and the corresponding hash (or a value
  32 # guaranteed to generate a "missing" result) used
  33 #
  34 # if topdeps is provided (and matches <branch>:<hash> e.g. "t/foo:1234") then
  35 # when depsblob is requested and the current branch is <branch> then instead
  36 # of the normal output, <hash>^{blob} will be output instead which can be
  37 # used to substitute an index or working tree version of a .topdeps file
  38 #
  39 # input must be a list of full ref names one per line
  40 #
  41 # output is 5, 6 or 7 lines per input line matching /^$topbases/
  42 # to feed to:
  43 #
  44 #   git cat-file --batch-check='%(objectname) %(objecttype) %(rest)'
  45 #
  46 # if both depsblob and msgblob are true depsblob is output before msgblob and
  47 # both always come after the fixed first 5 lines
  48 #
  49 # if chkblob is not empty an additional line will precede all other output
  50 # that verifies the existence of the chkblob object (and resolves it to a hash)
  51 #
  52 # note that if teeout is non-empty it will always be truncated before starting
  53 # to write the output even if no output is produced; also note that unlike the
  54 # other scripts this one writes to teeout simultaneously with stdout
  55 #
  56
  57 BEGIN { exitcode = "" }
  58 function exitnow(e) { exitcode=e; exit e }
  59 END { if (exitcode != "") exit exitcode }
  60
  61 BEGIN {
  62         sub(/\/+$/, "", topbases)
  63         if (topbases == "") exitnow(2)
  64         topbases = topbases "/"
  65         tblen = length(topbases)
  66         tbdrop = tblen + 1
  67         if (headbase == "") {
  68                 if (topbases !~ /^refs\//) exitnow(2)
  69                 if (topbases ~ /^refs\/remotes\//) {
  70                         if (topbases !~ /^refs\/remotes\/[^\/]+\/[^\/]+\//) exitnow(2)
  71                         headbase = topbases
  72                         sub(/\/[^\/]+\/$/, "/", headbase)
  73                 } else {
  74                         headbase = "refs/heads/"
  75                 }
  76         } else {
  77                 sub(/\/+$/, "", headbase)
  78                 if (headbase == "") exitnow(2)
  79                 headbase = headbase "/"
  80         }
  81         if (topdeps ~ /^[^ \t\r\n:]+:[0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f]+$/) {
  82                 colonat = index(topdeps, ":")
  83                 topdepsbr = substr(topdeps, 1, colonat - 1)
  84                 topdepsha = tolower(substr(topdeps, colonat + 1))
  85         }
  86         if (topmsg ~ /^[^ \t\r\n:]+:[0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f][0-9A-Fa-f]+$/) {
  87                 colonat = index(topmsg, ":")
  88                 topmsgbr = substr(topmsg, 1, colonat - 1)
  89                 topmsgha = tolower(substr(topmsg, colonat + 1))
  90         }
  91         if (teeout != "") printf "" >teeout
  92 }
  93
  94 function doprint(line) {
  95         if (teeout != "") print line >teeout
  96         print line
  97 }
  98
  99 function quotevar(v) {
 100         gsub(/\047/, "\047\\\047\047", v)
 101         return "\047" v "\047"
 102 }
 103
 104 function rmrefs() {
 105         if (refsfile != "" && rmrf) {
 106                 system("rm -f " quotevar(refsfile))
 107                 rmrf = 0
 108                 refsfile = ""
 109         }
 110 }
 111 END { rmrefs() }
 112
 113 function init(_e) {
 114         if (refsfile != "") {
 115                 while ((_e = (getline info <refsfile)) > 0) {
 116                         cnt = split(info, scratch, " ")
 117                         if (cnt < 2 || scratch[1] == "" || scratch[2] == "") continue
 118                         if (pckdrefs) {
 119                                 swapfield = scratch[1]
 120                                 scratch[1] = scratch[2]
 121                                 scratch[2] = swapfield
 122                         }
 123                         if (scratch[1] ~ /^refs\/./ &&
 124                             scratch[2] ~ /^[0-9a-fA-F][0-9a-fA-F][0-9a-fA-F][0-9a-fA-F]+$/)
 125                                 refs[scratch[1]] = scratch[2]
 126                 }
 127                 close(refsfile)
 128                 if (_e < 0) exitnow(2)
 129         }
 130         rmrefs()
 131 }
 132
 133 BEGIN {
 134         if (chkblob != "") doprint(chkblob "^{blob}" " check ?")
 135 }
 136
 137 NR == 1 {init()}
 138
 139 function getref(r) { return refsfile == "" ? r : (refs[r] ? refs[r] : "?") }
 140
 141 NF == 1 && substr($1, 1, tblen) == topbases {
 142         bn = substr($1, tbdrop)
 143         if (bn == "") next
 144         baseref = getref(topbases bn)
 145         headref = getref(headbase bn)
 146         doprint(baseref " " bn " :")
 147         doprint(baseref "^0")
 148         doprint(headref "^0")
 149         doprint(baseref "^{tree}")
 150         doprint(headref "^{tree}")
 151         if (depsblob) {
 152                 if (bn == topdepsbr)
 153                         doprint(topdepsha "^{blob}")
 154                 else
 155                         doprint(headref "^{tree}:.topdeps")
 156         }
 157         if (msgblob) {
 158                 if (bn == topmsgbr)
 159                         doprint(topmsgha "^{blob}")
 160                 else
 161                         doprint(headref "^{tree}:.topmsg")
 162         }
 163 }