From 04fd20d62b4e2b5a048298fa4177f09fb8353078 Mon Sep 17 00:00:00 2001
From: Eugene Shalygin <eugene.shalygin@gmail.com>
Date: Thu, 15 Nov 2018 18:20:02 +0100
Subject: [PATCH] cmake: read project version from the version.hpp file

---
 CMakeLists.txt                       |  9 ++++++---
 cmake/Modules/LibtorrentMacros.cmake | 25 +++++++++++++++++++++++++
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2c1a60f55..3f5268e20 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,15 +1,18 @@
 cmake_minimum_required(VERSION 3.12.0 FATAL_ERROR)
 
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules)
+include(LibtorrentMacros)
+
+read_version("${CMAKE_CURRENT_SOURCE_DIR}/include/libtorrent/version.hpp" VER_MAJOR VER_MINOR VER_TINY)
+
 project(libtorrent
 	DESCRIPTION "Bittorrent library"
-	VERSION 1.2.0
+	VERSION ${VER_MAJOR}.${VER_MINOR}.${VER_TINY}
 )
 set (SOVERSION "10")
 
-list(APPEND CMAKE_MODULE_PATH ${libtorrent_SOURCE_DIR}/cmake/Modules)
 include(GNUInstallDirs)
 include(GeneratePkgConfig)
-include(LibtorrentMacros)
 
 set(libtorrent_include_files
 	add_torrent_params
diff --git a/cmake/Modules/LibtorrentMacros.cmake b/cmake/Modules/LibtorrentMacros.cmake
index e73eb0e1f..e73fbfe5a 100644
--- a/cmake/Modules/LibtorrentMacros.cmake
+++ b/cmake/Modules/LibtorrentMacros.cmake
@@ -80,3 +80,28 @@ function(select_cxx_standard _target _minimal_supported_version)
 
 	message(STATUS "Building in C++${_std} mode")
 endfunction()
+
+# function for parsing version variables that are set in version.hpp file
+# the version identifiers there are defined as follows:
+# #define LIBTORRENT_VERSION_MAJOR 1
+# #define LIBTORRENT_VERSION_MINOR 2
+# #define LIBTORRENT_VERSION_TINY 0
+
+function(read_version _verFile _outVarMajor _outVarMinor _outVarTiny)
+	file(STRINGS ${_verFile} verFileContents REGEX ".+LIBTORRENT_VERSION_[A-Z]+.[0-9]+.*")
+# 	message(STATUS "version file contents: ${verFileContents}")
+	# the verFileContents variable contains something like the following:
+	# #define LIBTORRENT_VERSION_MAJOR 1;#define LIBTORRENT_VERSION_MINOR 2;#define LIBTORRENT_VERSION_TINY 0
+	set(_regex ".+_MAJOR +([0-9]+);.+_MINOR +([0-9]+);.+_TINY +([0-9]+)")
+	 # note quotes around _regex, they are needed because the variable contains semicolons
+	string(REGEX MATCH "${_regex}" _tmp "${verFileContents}")
+	if (NOT _tmp)
+		message(FATAL_ERROR "Could not detect project version number from ${_verFile}")
+	endif()
+
+# 	message(STATUS "Matched version string: ${_tmp}")
+
+	set(${_outVarMajor} ${CMAKE_MATCH_1} PARENT_SCOPE)
+	set(${_outVarMinor} ${CMAKE_MATCH_2} PARENT_SCOPE)
+	set(${_outVarTiny} ${CMAKE_MATCH_3} PARENT_SCOPE)
+endfunction()