diffmsg

#!/bin/awk -f
# create release message for MMG-CI releases
# feeds on git diff --raw

BEGIN {

  # map uncommon apk names to conventional names for translation
  delete appmap
  appmap["GoogleBackupTransport"]     = "Google sync adapters"
  appmap["GoogleCalendarSyncAdapter"] = "Google sync adapters"
  appmap["GoogleContactsSyncAdapter"] = "Google sync adapters"
  appmap["MicroGGMSCore"]             = "MicroG"
  appmap["MicroGGSFProxy"]            = "GSF proxy"
  appmap["MicroGUNLP"]                = "UNLP"
  appmap["Phonesky"]                  = "Playstore"

  # init stateful vars
  # arrays and index counters
  appc = 0
  binc = 0
  cerc = 0
  delete appv
  delete binv
  delete cerv

}

# git diff --raw format
# (p = number of parents of commit)
# (SP = space char)
# { ":" }*p { mode SP }*(p+1) { hash SP }*(p+1) status SP { filepath SP }*?
# 0..p modes and hashes are of parents, (p+1)ths are of the child
# IDK anything about filepaths
#
# example:
# :000000 100644 0000000 3abb859 A README.md
# ::100644 100644 100644 08576ac 08576ac c4585d8 MM system/bin/npem

# skip non-diff lines
# they don't start with colons
!/^:[:]*/ { next }

# process each line and take out useful fields
# set variables: file, action
{

  # match the pattern and get number of colons
  # number of colons = number of parents of commit
  match($0, "^:[:]*")
  parents = RLENGTH
  offset = (parents + 1) * 2

  # get change status and build array of filepaths
  change = $(offset + 1)
  filec = 0
  delete filev
  for (i = offset + 2; i <= NF; i++) {
    filev[filec] = $i
    filec += 1
  }

  # I have no idea what to with merges
  # only supports non-merge commits for now
  if (parents != 1) next
  if (change ~ "C" || change ~ "R")
    # for copies and renames, first filepath is src, second is dst
    file = filev[1]
  else
    # for everything else there is only one filepath
    file = filev[0]

  # find action by matching status code
  if (change ~ "A" || change ~ "C" || change ~ "R")
    action = "added"
  else if (change ~ "M")
    action = "updated"
  else if (change ~ "D")
    action = "deleted"
  else
    # unknown status, skip
    next

}

# match file with various paths
# add their string and action to relevant arrays
# array[i, 0] = string
# array[i, 1] = action

# string literals used as regex patterns are parsed twice by awk
# all escapes need to be doubled for simpler implementations

file ~ "^system/(priv-)?app/[^/]*/(-[^/]*-/)?[^/]*\\.apk$" {
  split(file, arr, "/")
  str = arr[3]
  if (str in appmap)
    str = appmap[str]
  for (i = 0; i < appc; i++)
    if (appv[i, 0] == str) next
  appv[appc, 0] = str
  appv[appc, 1] = action
  appc += 1
  next
}
file ~ "^system/(x)?bin/(-[^/]*-/)?[^/]*$" {
  n = split(file, arr, "/")
  str = "`" arr[n] "`"
  for (i = 0; i < binc; i++)
    if (binv[i, 0] == str) next
  binv[binc, 0] = str
  binv[binc, 1] = action
  binc += 1
  next
}
file ~ "^system/framework/(-[^/]*-/)?com\\.google\\.android\\.maps\\.jar$" {
  str = "MicroG maps API v1"
  for (i = 0; i < binc; i++)
    if (binv[i, 0] == str) next
  binv[binc, 0] = str
  binv[binc, 1] = "updated"
  binc += 1
  next
}
file ~ "^util/certs/repo/[^/]*\\.cer$" {
  split(file, arr, "/")
  repo = substr(arr[4], 1, length(arr[4]) - length(".cer"))
  str = "cert for repo" " " repo
  for (i = 0; i < cerc; i++)
    if (cerv[i, 0] == str) next
  cerv[cerc, 0] = str
  cerv[cerc, 1] = "changed"
  cerc += 1
  next
}
file ~ "^util/certs/system/(priv-)?app/[^/]*/(-[^/]*-/)?[^/]*\\.cer$" {
  split(file, arr, "/")
  str = "cert for app" " " arr[5]
  for (i = 0; i < cerc; i++)
    if (cerv[i, 0] == str) next
  cerv[cerc, 0] = str
  cerv[cerc, 1] = "changed"
  cerc += 1
  next
}

END {

  # printf fmt string
  fmt = "  - %s %s\n"

  # loop through all non-empty lists and print elements
  if (appc) {
    print("- Apps changed:")
    for (i = 0; i < appc; i++) {
      printf(fmt, appv[i, 1], appv[i, 0])
    }
    print("")
  }
  if (binc) {
    print("- Binaries changed:")
    for (i = 0; i < binc; i++) {
      printf(fmt, binv[i, 1], binv[i, 0])
    }
    print("")
  }
  if (cerc) {
    print("- Certs changed:")
    for (i = 0; i < cerc; i++) {
      printf(fmt, cerv[i, 1], cerv[i, 0])
    }
    print("")
  }

}