[beast: 1/11] MISC: mkbuildid.sh: add script to generate build id

[Tim Janik <timj src gnome org>]

commit c090af18f533da6f49d21ec6f38fb5e30171e9f5
Author: Tim Janik <timj gnu org>
Date:   Wed Oct 19 10:13:00 2016 +0200

    MISC: mkbuildid.sh: add script to generate build id
    
    Signed-off-by: Tim Janik <timj gnu org>

 misc/mkbuildid.sh |   56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 topbuildid.hh     |    3 ++
 2 files changed, 59 insertions(+), 0 deletions(-)
---
diff --git a/misc/mkbuildid.sh b/misc/mkbuildid.sh
new file mode 100755
index 0000000..c3bea1a
--- /dev/null
+++ b/misc/mkbuildid.sh
@@ -0,0 +1,56 @@
+#!/bin/bash
+set -e
+
+# Usage: mkbuildid.sh [-p] [ccfile] [hhfile]
+# Display BuildID and update buildid() source file
+
+SCRIPTNAME="$(basename "$0")" ; die() { e="$1"; shift; echo "$SCRIPTNAME: $*" >&2; exit "$e"; }
+SCRIPTDIR="$(dirname "$(readlink -f "$0")")"
+
+# Extract version, see: https://www.debian.org/doc/debian-policy/ch-controlfields.html#s-f-Version
+FALLBACK_VERSION="$(sed -nr "/^AC_INIT\b/{ s/^[^,]*,[^0-9]*([A-Za-z0-9.:~+-]*).*/\1/; p; }" 
$SCRIPTDIR/../configure.ac)"
+test -n "$FALLBACK_VERSION" || die 7 "failed to detect AC_INIT in $SCRIPTDIR/../configure.ac"
+
+test " $1" = " -p" && { PRINT=true; shift; } || PRINT=false
+BUILDID_CC="$1"
+BUILDID_HH="$2"
+DOTGIT=`git rev-parse --git-dir 2>/dev/null` || true
+
+gen_buildid() {
+  test -e "$DOTGIT" ||                         # not in a git-tracked source tree
+      { printf %s "${FALLBACK_VERSION-0.0.0}-untracked" ; return ; }
+  COMMITID="${1-HEAD}"
+  DESC=$(git describe --match '[0-9]*.*[0-9]' --abbrev=5 $COMMITID)
+  test "$DESC" != "${DESC%%-*}" ||             # HEAD is on release tag
+      { echo "$DESC" ; return ; }
+  # HEAD has commits on top of last release tag, transform 0.0.0-7-gabc -> 0.0.1~7-gabc
+  MICRO=$(printf %s "$DESC" | sed 's/^[^-]*\b\([0-9]\+\)-.*/\1/')
+  [[ "$MICRO" =~ ^[0-9]+$ ]] || die 7 "failed to detect MICRO in $DESC"
+  MICRO=$(expr 1 + "$MICRO")
+  NEXT=$(printf %s "$DESC" | sed "s/^\([^-]*\)\b\([0-9]\+\)-/\1$MICRO~wip/")
+  printf %s "$NEXT"
+}
+
+BUILDID=$(gen_buildid HEAD)
+
+BUILDID_INCLUDE=
+test -z "$BUILDID_HH" || BUILDID_INCLUDE="#include \"$BUILDID_HH\""
+
+BUILDID_CODE=$(cat <<__EOF
+$BUILDID_INCLUDE
+namespace Internal {
+  const char* buildid() { return "$BUILDID"; }
+}
+__EOF
+)
+
+if $PRINT ; then
+  echo "$BUILDID"
+fi
+
+test -z "$BUILDID_CC" || {
+  if test ! -e "$BUILDID_CC" || test "$(cat "$BUILDID_CC")" != "$BUILDID_CODE" ; then
+    echo "  UPDATE   $BUILDID_CC" >&2
+    echo "$BUILDID_CODE" > "$BUILDID_CC"
+  fi
+}
diff --git a/topbuildid.hh b/topbuildid.hh
new file mode 100644
index 0000000..7cd5ad1
--- /dev/null
+++ b/topbuildid.hh
@@ -0,0 +1,3 @@
+namespace Internal {
+const char* buildid() __attribute__ ((const));
+} // Internal