cmake: replace BUILD_... prefix of cmake options with ZXING_...

Care has been taken to keep the old names functional for a transition
period. A cmake warning is emitted in this case.

CMakeLists.txt

@@ -2,17 +2,16 @@ cmake_minimum_required(VERSION 3.15)
 
 project(ZXing)
 
-# option (BUILD_WRITERS "Build with writer support (encoders)" ON)
-set(BUILD_WRITERS "ON" CACHE STRING "Build with old and/or new writer (encoder) backend (OFF/ON/OLD/NEW/BOTH)")
-option (BUILD_READERS "Build with reader support (decoders)" ON)
-option (BUILD_EXAMPLES "Build the example barcode reader/writer applications" ON)
-option (BUILD_BLACKBOX_TESTS "Build the black box reader/writer tests" OFF)
-option (BUILD_UNIT_TESTS "Build the unit tests (don't enable for production builds)" OFF)
-option (BUILD_PYTHON_MODULE "Build the python module" OFF)
-option (BUILD_C_API "Build the C-API" OFF)
-option (BUILD_EXPERIMENTAL_API "Build with experimental API" OFF)
-option (ZXING_USE_BUNDLED_ZINT "Use the bundled libzint for barcode creation/generation" ON)
-set(BUILD_DEPENDENCIES "AUTO" CACHE STRING "Fetch from github or use locally installed (AUTO/GITHUB/LOCAL)")
+option (ZXING_READERS "Build with reader support (decoders)" ON)
+set    (ZXING_WRITERS "ON" CACHE STRING "Build with old and/or new writer (encoder) backend (OFF/ON/OLD/NEW/BOTH)")
+option (ZXING_USE_BUNDLED_ZINT "Use the bundled libzint for barcode creation/writing" ON)
+option (ZXING_C_API "Build the C-API" OFF)
+option (ZXING_EXPERIMENTAL_API "Build with experimental API" OFF)
+option (ZXING_EXAMPLES "Build the example barcode reader/writer applications" ON)
+option (ZXING_BLACKBOX_TESTS "Build the black box reader/writer tests" OFF)
+option (ZXING_UNIT_TESTS "Build the unit tests (don't enable for production builds)" OFF)
+option (ZXING_PYTHON_MODULE "Build the python module" OFF)
+set    (ZXING_DEPENDENCIES "AUTO" CACHE STRING "Fetch from github or use locally installed (AUTO/GITHUB/LOCAL)")
 
 if (WIN32)
     option (BUILD_SHARED_LIBS "Build and link as shared library" OFF)
@@ -22,8 +21,8 @@ endif()
 
 if (MSVC)
     add_definitions (-DUNICODE -D_UNICODE -D_CRT_SECURE_NO_WARNINGS)
-    option (LINK_CPP_STATICALLY "MSVC only, link standard library statically (/MT and /MTd)" OFF)
-    if (LINK_CPP_STATICALLY)
+    option (ZXING_LINK_CPP_STATICALLY "MSVC only, link standard library statically (/MT and /MTd)" OFF)
+    if (LINK_CPP_STATICALLY OR ZXING_LINK_CPP_STATICALLY)
         set(CMAKE_MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
     endif()
 endif()
@@ -35,26 +34,43 @@ if (NOT CMAKE_BUILD_TYPE)
     set_property (CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS "Debug" "Release" "MinSizeRel" "RelWithDebInfo")
 endif()
 
-if (NOT (BUILD_READERS OR BUILD_WRITERS))
-    message(FATAL_ERROR "At least one of BUILD_READERS/BUILD_WRITERS must be enabled.")
+# provide backward compatibility for deprecated BUILD_... options
+if (DEFINED BUILD_READERS)
+    set (ZXING_READERS ${BUILD_READERS})
+endif()
+if (DEFINED BUILD_WRITERS)
+    set (ZXING_WRITERS ${BUILD_WRITERS})
+endif()
+if (DEFINED BUILD_EXAMPLES)
+    set (ZXING_EXAMPLES ${BUILD_EXAMPLES})
+endif()
+if (DEFINED BUILD_PYTHON_MODULE)
+    set (ZXING_PYTHON_MODULE ${BUILD_PYTHON_MODULE})
+endif()
+if (DEFINED BUILD_DEPENDENCIES)
+    set (ZXING_DEPENDENCIES ${BUILD_DEPENDENCIES})
+endif()
+
+if (NOT (ZXING_READERS OR ZXING_WRITERS))
+    message(FATAL_ERROR "At least one of ZXING_READERS/ZXING_WRITERS must be enabled.")
 endif()
 
-if (BUILD_UNIT_TESTS AND (NOT BUILD_WRITERS OR NOT BUILD_READERS))
+if (ZXING_UNIT_TESTS AND (NOT ZXING_WRITERS OR NOT ZXING_READERS))
     message("Note: To build with unit tests, the library will be build with READERS and WRITERS.")
-    set (BUILD_WRITERS ON)
-    set (BUILD_READERS ON)
+    set (ZXING_WRITERS ON)
+    set (ZXING_READERS ON)
 endif()
 
-set(BUILD_WRITERS_LIST OFF ON OLD NEW BOTH)
-set_property(CACHE BUILD_WRITERS PROPERTY STRINGS ${BUILD_WRITERS_LIST})
-if(NOT BUILD_WRITERS IN_LIST BUILD_WRITERS_LIST)
-    message(FATAL_ERROR "BUILD_WRITERS must be one of ${BUILD_WRITERS_LIST}")
+set(ZXING_WRITERS_LIST OFF ON OLD NEW BOTH)
+set_property(CACHE ZXING_WRITERS PROPERTY STRINGS ${ZXING_WRITERS_LIST})
+if(NOT ZXING_WRITERS IN_LIST ZXING_WRITERS_LIST)
+    message(FATAL_ERROR "ZXING_WRITERS must be one of ${ZXING_WRITERS_LIST}")
 endif()
 
-set(BUILD_DEPENDENCIES_LIST AUTO GITHUB LOCAL)
-set_property(CACHE BUILD_DEPENDENCIES PROPERTY STRINGS ${BUILD_DEPENDENCIES_LIST})
-if(NOT BUILD_DEPENDENCIES IN_LIST BUILD_DEPENDENCIES_LIST)
-    message(FATAL_ERROR "BUILD_DEPENDENCIES must be one of ${BUILD_DEPENDENCIES_LIST}")
+set(ZXING_DEPENDENCIES_LIST AUTO GITHUB LOCAL)
+set_property(CACHE ZXING_DEPENDENCIES PROPERTY STRINGS ${ZXING_DEPENDENCIES_LIST})
+if(NOT ZXING_DEPENDENCIES IN_LIST ZXING_DEPENDENCIES_LIST)
+    message(FATAL_ERROR "ZXING_DEPENDENCIES must be one of ${ZXING_DEPENDENCIES_LIST}")
 endif()
 
 if (NOT DEFINED CMAKE_CXX_STANDARD)
@@ -70,18 +86,18 @@ enable_testing()
 
 include(zxing.cmake)
 
-if (BUILD_EXAMPLES)
+if (ZXING_EXAMPLES)
     add_subdirectory (example)
 endif()
-if (BUILD_BLACKBOX_TESTS)
+if (ZXING_BLACKBOX_TESTS)
     add_subdirectory (test/blackbox)
 endif()
-if (BUILD_UNIT_TESTS)
+if (ZXING_UNIT_TESTS)
     add_subdirectory (test/unit)
 endif()
-if (BUILD_PYTHON_MODULE)
+if (ZXING_PYTHON_MODULE)
     add_subdirectory (wrappers/python)
 endif()
-if (BUILD_C_API)
+if (ZXING_C_API)
     add_subdirectory (wrappers/c)
 endif()

README.md

@@ -101,7 +101,7 @@ These are the generic instructions to build the library on Windows/macOS/Linux.
 
 1. Make sure [CMake](https://cmake.org) version 3.15 or newer is installed.
 2. Make sure a C++17 compliant compiler is installed (minimum VS 2019 16.8 / gcc 7 / clang 5).
-3. See the cmake `BUILD_...` options to enable the testing code, python wrapper, etc.
+3. See the cmake `ZXING_...` options to enable the testing code, python wrapper, etc.
 
 ```
 git clone https://github.com/zxing-cpp/zxing-cpp.git --single-branch --depth 1