From caddbf663d7d931a0b272a00ced33a57f8141ff6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Milo=C5=A1=20Komar=C4=8Devi=C4=87?=
 <miloskomarcevic@aim.com>
Date: Wed, 25 Jan 2023 16:31:33 +0100
Subject: [PATCH] Fix shared object versioning

---
 CMakeLists.txt     | 9 +++++++++
 src/CMakeLists.txt | 2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c7e6830a..7ef1ea8c 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,6 +12,15 @@ project(exiv2          # use TWEAK to categorize the build
     LANGUAGES C CXX
 )
 
+# Shared Object versioning (SemVer-like: must bump major on API breakage)
+if(PROJECT_VERSION_MAJOR EQUAL 0)
+  # support legacy scheme (e.g. 0.27.x -> 27)
+  set(EXIV2LIB_SOVERSION ${PROJECT_VERSION_MINOR})
+else()
+  # restart from 30
+  math(EXPR EXIV2LIB_SOVERSION "30 + (${PROJECT_VERSION_MAJOR} - 1)")
+endif()
+
 if(NOT CMAKE_BUILD_TYPE)
   set (CMAKE_BUILD_TYPE Release)
 endif()
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index bc3c18c0..41a672e8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -160,7 +160,7 @@ endif()
 
 set_target_properties( exiv2lib PROPERTIES
     VERSION       ${PROJECT_VERSION}
-    SOVERSION     ${PROJECT_VERSION_MINOR}
+    SOVERSION     ${EXIV2LIB_SOVERSION}
     OUTPUT_NAME   exiv2
     PDB_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
     COMPILE_FLAGS ${EXTRA_COMPILE_FLAGS}