#!/bin/bash
#
# This script checks ABI compatibility of the current branch against
# a prior release (git tag) of the same branch.
#
# We recommend to execute this script in an empty, temporary directory.
# See below for details why this is useful.
#
# Requirements:
#
# CMake, a POSIX shell (bash), abi-checker, and perl (for abi checker).
# This script has been tested only on Linux. After the check it *tries*
# to open the compatibility report with the standard browser (xdg-open).
#
# Usage:
#
# $ /path-to/abi-check  FLTK_DIR  MINOR_VERSION  P1  P2
#
# Parameters:
#
# FLTK_DIR        Where the FLTK source files are (must be a git checkout).
#                 This must be a "clean" working copy: this script checks
#                 out the prior version (release tag) and the tip of the
#                 branch (in this order). The last checkout is left in place.
#
# MINOR_VERSION   FLTK major.minor version, e.g. 1.3, 1.4, or 1.5.
#
# P1              First FLTK patch version to compare (prior release)
#
# P2              Current version (tip) of the development branch. This
#                 version must be given as well. If the version in git has
#                 not yet been updated you can enter the "next" version.
#                 This is typically the case if you check the current branch
#                 for ABI issues *before* preparation of the next release.
#
# Examples:
#
# /path-to/abi-check  /path-to/fltk-1.3  1.3  10  11
# /path-to/abi-check  /path-to/fltk-1.4  1.4   3   4
#
# The latter checks ABI compatibility of git tag "release-1.4.3" and the
# HEAD of the selected development branch (see below) as version 1.4.4. This
# can be done even if the version number in 'branch-1.4' is still 1.4.3.
#
# This is typically used to check ABI compatibility of a development branch
# against the latest release of the same branch, but can also be used to test
# any prior version of the branch against the current tip of the branch.
#
# The script uses `cmake --build` and `cmake --install` for simplicity, but
# you can select any CMake generator you like, as long as the script can
# be executed by a POSIX shell and `cmake --install` works for the given
# generator (not tested for Xcode and Visual Studio).
# "Installing" the build ensures that all header files including generated
# ones are present where `abi-compliance-checker.pl` expects them to be.
#
# This script is known to work with FLTK versions since 1.3.6. Older versions
# may not compile, build, or install correctly with current compilers.
#
# Warning: this script does NOT check runtime errors, e.g. when checking out
# git versions, or when building and installing FLTK libs. Please check the
# logs that are displayed and/or stored in `logs` for errors.
#
# Error checks may be added in a later version of this script.
#
# ------------------------------------------------------------------------------
#
# Some variables are "constants" in this script and need to be edited for
# use in other build environments. The variables that need to be edited for
# your build environment are documented below:
#
# ABI_PATH        Directory of ABI checker ("abi-compliance-checker.pl"); can
#                 be empty (default) if the ABI checker is in the user's PATH.
#                 If the path is given it must have a trailing slash ('/').
#
# ABI_CHECKER     Name of the ABI checker executable (script). The default
#                 ("abi-compliance-checker.pl") should be correct.
#
# GENERATOR       CMake generator, e.g. "Ninja", "Unix Makefiles" (see CMake docs).
#
# PARALLEL        Number of parallel build jobs, recommended for "Unix Makefiles".
#                 Use CMake syntax "--parallel=N" if needed.
#                 Ninja uses the number of available cores if not specified.
#
# CMAKE_WARNINGS  Should be empty; "-Wno-dev" suppresses "developer warnings".
#
# CXX_FLAGS       Can be used to suppress compiler warnings (not recommended).
#
# CXX_STANDARD    Default: "11" (C++11); can be set to "98" (C++98) for 1.3.
#
# This script creates several subdirectories in the current working directory
# (referred as $PWD below). The files created by the script can be deleted
# after the check.
#
# Both FLTK versions ($VER) will be built in $PWD/build/$VER and installed in
# $PWD/bin/$VER, resp.. These folders are cleared before build/installation
# but left as-is after the abi-check. They must be deleted manually.
#
# Example: Folders created for ABI check of FLTK 1.4.2 vs 1.4.3:
#
# .   (current dir: $PWD)
# ├── bin
# │   ├── 1.4.2
# │   └── 1.4.3
# ├── build
# │   ├── 1.4.2
# │   └── 1.4.3
# ├── compat_reports
# │   └── fltk
# ├── logs
# │   └── fltk
# └── xml
#     ├── fltk-1.4.2.xml
#     └── fltk-1.4.3.xml
#
# -----------------------------------------------------
# Edit the following "constants" for your environment,
# see above for documentation:
# -----------------------------------------------------
#
      ABI_PATH=""
   ABI_CHECKER="abi-compliance-checker.pl"
     GENERATOR="Ninja"
      PARALLEL=""
CMAKE_WARNINGS=""
     CXX_FLAGS=""
  CXX_STANDARD="11"

# -----------------------------------------------------
# End of constants, no need to edit anything below.
# -----------------------------------------------------

# Define derived variables

   ABI_CHECKER="$ABI_PATH$ABI_CHECKER"
    SOURCE_DIR="$1"
      BASE_DIR="$PWD"
  BASE_VERSION="$2"
     BUILD_DIR="$BASE_DIR/build"
        PREFIX="$BASE_DIR/bin"

# CMake options -- in parts depending on the development branch.
#
# This could be simplified if the script was written only for the current
# FLTK version but for now (work in progress) it is written to be used for
# other FLTK versions (branches) as well, just in case older branches need
# a new release. It is intended that developers can use the latest script
# from the 'master' branch in older branches (1.3.6 and higher) as well.
#
# Default values are set first for FLTK 1.5 (master).

  BUILD_SHARED="-D FLTK_BUILD_SHARED_LIBS=ON"
   BUILD_CAIRO="-D FLTK_OPTION_CAIRO_WINDOW=ON"
   BUILD_FORMS="-D FLTK_BUILD_FORMS=ON"
   BUILD_FLUID="-D FLTK_BUILD_FLUID=OFF"
 BUILD_OPTIONS="-D FLTK_BUILD_FLTK_OPTIONS=OFF"

# Version dependent options are set or overriden here:

if test v$BASE_VERSION = v1.5; then
    BASE_BRANCH="master"
elif test v$BASE_VERSION = v1.4; then
    BASE_BRANCH="branch-1.4"
else # 1.3: some old option names, some options are not present
    BASE_BRANCH="branch-1.3"
  BUILD_SHARED="-D OPTION_BUILD_SHARED_LIBS=ON"
   BUILD_CAIRO="-D OPTION_CAIRO=ON"
   BUILD_FORMS=""
   BUILD_FLUID=""
 BUILD_OPTIONS=""
fi

V1=$BASE_VERSION.$3
V2=$BASE_VERSION.$4

# define a common function for both builds

build_and_install() {

  REL="$1"
  VER="$2"
  XML="xml/fltk-$VER.xml"

  # generate XML file for ABI checker

  echo
  echo "--------  Creating XML file $XML for abi-checker  --------"
  echo

cat > $XML << EOF
<version>
    $VER
</version>
<headers>
    $PREFIX/$VER/include/FL/
</headers>
<skip_headers>
    win32.H
    mac.H
</skip_headers>
<libs>
    $PREFIX/$VER/lib/
</libs>
EOF

  pushd $SOURCE_DIR

  echo
  echo "--------  Checking out Git tag/branch $REL for $VER in $PWD  --------"
  echo

  git checkout $REL

  echo
  echo "--------  Configuring FLTK $VER in $BUILD_DIR/$VER --------"
  echo

  cmake $CMAKE_WARNINGS \
    -S . -B $BUILD_DIR/$VER \
    -G "$GENERATOR" \
    -D CMAKE_BUILD_TYPE=Debug \
    -D CMAKE_CXX_FLAGS_INIT="$CXX_FLAGS" \
    -D CMAKE_INSTALL_PREFIX=$PREFIX/$VER \
    -D FLTK_BUILD_EXAMPLES=OFF \
    -D FLTK_BUILD_TEST=OFF \
    -D CMAKE_CXX_STANDARD=$CXX_STANDARD \
    $BUILD_SHARED $BUILD_FLUID $BUILD_OPTIONS $BUILD_FORMS $BUILD_CAIRO

  echo
  echo "--------  Building FLTK $VER in $BUILD_DIR/$VER  --------"
  echo

  cmake --build $BUILD_DIR/$VER $PARALLEL

  echo
  echo "--------  Installing FLTK $VER in $PREFIX/$VER  --------"
  echo

  rm -rf $PREFIX/$VER
  cmake --install $BUILD_DIR/$VER

  popd
}

# create subdirectory 'xml' if it doesn't exist

[[ ! -d xml ]] && mkdir xml
[[ ! -d compat_reports ]] && mkdir compat_reports

build_and_install release-$V1 $V1

build_and_install $BASE_BRANCH $V2

$ABI_CHECKER \
  -lib fltk \
  -old xml/fltk-${V1}.xml \
  -new xml/fltk-${V2}.xml

xdg-open compat_reports/fltk/${V1}_to_${V2}/compat_report.html