Adding an option to build a DLL under windows

This adds a BUILD_LIBRARY flag, allowing developers to create libwebvtt.dll. Added instructions for doign this in a MinGW environment.

CMakeLists.txt

@@ -9,6 +9,10 @@ set(CMAKE_POSITION_INDEPENDENT_CODE ON)
 SET(GCC_COVERAGE_COMPILE_FLAGS "-Wno-narrowing")
 SET(CMAKE_CXX_FLAGS  "${CMAKE_CXX_FLAGS} ${GCC_COVERAGE_COMPILE_FLAGS}")
 
+add_definitions(-DWEBVTT_BUILD_LIBRARY)
+if (BUILD_LIBRARY)
+  set(-DWEBVTT_BUILD_LIBRARY 1)
+endif (BUILD_LIBRARY)
 
 add_subdirectory("src")
 add_subdirectory("test")

README.md

@@ -38,6 +38,31 @@ Once built, the static library and include files are available at these location
 * Static library: `build/src/webvttxx/libwebvttxx.a`
 * Include: `include/webvttxx`
 
+### Building A dll on Windows (MinGW)
+[CMake](https://cmake.org/) is also used on Windows for running the builds and tests, but it's recommended to use [MSYS2](https://www.msys2.org/) to create the Mingw64 build environment.
+
+When using CMake, it's recommended that builds take place outside of the main project source, such as in a `build` directory.
+
+1. [Download, install, and update MSYS2 using the steps on the MSYS2 homepage](https://www.msys2.org/)
+2. Open the MSYS2 terminal, choosing "Mingw-w64 64 bit" when prompted
+3. Change directories to the working folder where you want to build libwebvtt. Keep in mind that the C:\ for Windows is mounted under `/c/` in MinGW. For example, if the build location is "C:\Users\username\sources\", then do `cd /c/users/username/sources/`
+
+```bash
+# clone the project
+git clone https://github.com/alexa/webvtt.git
+
+# change directories to the project root
+cd webvtt
+
+# create and enter the build directory
+mkdir build && cd build
+
+# configure the project with CMake, using the MSYS generator
+cmake -G 'MSYS Makefiles' -DBUILD_LIBRARY=1 ..
+
+# compile the DLL
+make libwebvtt
+```
 
 ## Running Tests:
 

include/webvtt/util.h

@@ -54,6 +54,8 @@ extern "C" {
 #   define WEBVTT_CALLBACK __cdecl
 #   if WEBVTT_BUILD_LIBRARY
 #     define WEBVTT_EXPORT __declspec(dllexport)
+/* Expose private functions necessary to run the unit tests. */
+#     define WEBVTT_INTERN __declspec(dllexport)
 #   elif !WEBVTT_STATIC
 #     define WEBVTT_EXPORT __declspec(dllimport)
 #   else
@@ -64,6 +66,8 @@ extern "C" {
 #   if WEBVTT_OS_WIN32
 #     if WEBVTT_BUILD_LIBRARY
 #       define WEBVTT_EXPORT __declspec(dllexport)
+/* Expose private functions necessary to run the unit tests. */
+#       define WEBVTT_INTERN __declspec(dllexport)
 #     elif !WEBVTT_STATIC
 #       define WEBVTT_EXPORT __declspec(dllimport)
 #     else

src/webvtt/CMakeLists.txt

@@ -1,15 +1,28 @@
 cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
 
 add_definitions("-DACSDK_LOG_MODULE=captionslib")
-add_library(libwebvtt STATIC
-        alloc.c
-        cue.c
-        cuetext.c
-        error.c
-        lexer.c
-        node.c
-        parser.c
-        string.c)
+
+if (BUILD_LIBRARY AND WIN32 OR WIN64)
+  add_library(libwebvtt SHARED
+          alloc.c
+          cue.c
+          cuetext.c
+          error.c
+          lexer.c
+          node.c
+          parser.c
+          string.c)
+else (BUILD_LIBRARY AND WIN32 OR WIN64)
+  add_library(libwebvtt STATIC
+          alloc.c
+          cue.c
+          cuetext.c
+          error.c
+          lexer.c
+          node.c
+          parser.c
+          string.c)
+endif (BUILD_LIBRARY AND WIN32 OR WIN64)
 
 target_include_directories(libwebvtt PUBLIC
         "${libwebvtt_SOURCE_DIR}"

src/webvttxx/CMakeLists.txt

@@ -1,9 +1,14 @@
 cmake_minimum_required(VERSION 3.1 FATAL_ERROR)
 
-
-add_library(libwebvttxx STATIC
-        abstract_parser.cpp
-        file_parser.cpp)
+if (BUILD_LIBRARY AND WIN32 OR WIN64)
+  add_library(libwebvttxx OBJECT
+          abstract_parser.cpp
+          file_parser.cpp)
+else (BUILD_LIBRARY AND WIN32 OR WIN64)
+  add_library(libwebvttxx STATIC
+          abstract_parser.cpp
+          file_parser.cpp)
+endif (BUILD_LIBRARY AND WIN32 OR WIN64)
 
 target_include_directories(libwebvttxx PUBLIC
         "${PROJECT_SOURCE_DIR}/include")

test/unit/CMakeLists.txt

@@ -54,4 +54,9 @@ target_link_libraries(unittests
 set(TEST_FILE_DIR "${PROJECT_SOURCE_DIR}/test/unit")
 configure_file(test_config.h.in test_config.h @ONLY)
 
+if (WIN32 OR WIN64)
+  set(CMAKE_CXX_STANDARD_LIBRARIES "-static-libgcc -static-libstdc++ ${CMAKE_CXX_STANDARD_LIBRARIES}")
+  set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-Bstatic,--whole-archive -lwinpthread -Wl,--no-whole-archive")
+endif (WIN32 OR WIN64)
+
 add_test(NAME libwebvtt_tests COMMAND unittests)