Change detection method for checking package name changes

build/install-build-deps.sh

 #!/bin/bash -e
 
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # Script to install everything needed to build chromium (well, ideally, anyway)
 # See http://code.google.com/p/chromium/wiki/LinuxBuildInstructions
 # and http://code.google.com/p/chromium/wiki/LinuxBuild64Bit
 
 usage() {
   echo "Usage: $0 [--options]"
   echo "Options:"
   echo "--[no-]syms: enable or disable installation of debugging symbols"
   echo "--[no-]lib32: enable or disable installation of 32 bit libraries"
   echo "--[no-]arm: enable or disable installation of arm cross toolchain"
   echo "--[no-]chromeos-fonts: enable or disable installation of Chrome OS"\
        "fonts"
   echo "--no-prompt: silently select standard options/defaults"
   echo "Script will prompt interactively if options not given."
   exit 1
 }
 
+# Checks whether a particular package is available in the repos.
+# USAGE: $ package_exists <package name>
+package_exists() {
+  apt-cache pkgnames | grep -x "$1" > /dev/null 2>&1
+}
+
 while test "$1" != ""
 do
   case "$1" in
   --syms)                   do_inst_syms=1;;
   --no-syms)                do_inst_syms=0;;
   --lib32)                  do_inst_lib32=1;;
   --no-lib32)               do_inst_lib32=0;;
   --arm)                    do_inst_arm=1;;
   --no-arm)                 do_inst_arm=0;;
   --chromeos-fonts)         do_inst_chromeos_fonts=1;;
@@ skipping 82 matching lines @@
 # arm cross toolchain packages needed to build chrome on arm
 arm_list="libc6-armel-cross libc6-dev-armel-cross libgcc1-armel-cross
           libgomp1-armel-cross linux-libc-dev-armel-cross
           libgcc1-dbg-armel-cross libgomp1-dbg-armel-cross
           binutils-arm-linux-gnueabi cpp-arm-linux-gnueabi
           gcc-arm-linux-gnueabi g++-arm-linux-gnueabi
           libmudflap0-dbg-armel-cross"
 
 
 # Some package names have changed over time
-if apt-cache show ttf-mscorefonts-installer >/dev/null 2>&1; then
+if package_exists ttf-mscorefonts-installer; then
   dev_list="${dev_list} ttf-mscorefonts-installer"
 else
   dev_list="${dev_list} msttcorefonts"
 fi
-if apt-cache show libnspr4-dbg >/dev/null 2>&1; then
+if package_exists libnspr4-dbg; then
   dbg_list="${dbg_list} libnspr4-dbg libnss3-dbg"
   lib_list="${lib_list} libnspr4 libnss3"
 else
   dbg_list="${dbg_list} libnspr4-0d-dbg libnss3-1d-dbg"
   lib_list="${lib_list} libnspr4-0d libnss3-1d"
 fi
-if apt-cache show libjpeg-dev >/dev/null 2>&1; then
+if package_exists libjpeg-dev; then
   dev_list="${dev_list} libjpeg-dev"
 else
   dev_list="${dev_list} libjpeg62-dev"
 fi
-if [ "$(apt-cache pkgnames libudev1 2>&1)" == "libudev1" ] ; then
+if package_exists libudev1; then
   dev_list="${dev_list} libudev1"
 else
   dev_list="${dev_list} libudev0"
 fi
 
 
 # Some packages are only needed, if the distribution actually supports
 # installing them.
-if apt-cache show appmenu-gtk >/dev/null 2>&1; then
+if package_exists appmenu-gtk; then
   lib_list="$lib_list appmenu-gtk"
 fi
 
 # Waits for the user to press 'Y' or 'N'. Either uppercase of lowercase is
 # accepted. Returns 0 for 'Y' and 1 for 'N'. If an optional parameter has
 # been provided to yes_no(), the function also accepts RETURN as a user input.
 # The parameter specifies the exit code that should be returned in that case.
 # The function will echo the user's selection followed by a newline character.
 # Users can abort the function by pressing CTRL-C. This will call "exit 1".
 yes_no() {
@@ skipping 332 matching lines @@
              sed -e 's/[.]so[.][0-9].*/.so/' |
              sort -u); do
     [ "x${i##*/}" = "xld-linux.so" ] && continue
     [ -r "$i" ] && continue
     j="$(ls "$i."* | sed -e 's/.*[.]so[.]\([^.]*\)$/\1/;t;d' |
          sort -n | tail -n 1)"
     [ -r "$i.$j" ] || continue
     sudo ln -s "${i##*/}.$j" "$i"
   done
 fi