Make Emscripten build not depend on SDL2 or cubeb

While Emscripten has an SDL compabtility layer, it assumes that the
code is executing in the main browser process (and thus has access to
them DOM). The Infinite Mac project runs emulators in a worker thread
(for better performance) and has a custom API for the display, sound,
input, etc. Similarly, it does not need the cross-platform sound support
from cubeb, there there is a sound API as well.

This commit makes SDL (*_sdl.cpp) and cubeb-based (*_cubeb.cpp) code be
skipped when targeting Emscripten, and instead *_js.cpp files are used
instead (this is the cross-platform convention used by Chromium[^1], and
could be extended for other targets).

For hostevents.cpp and soundserver.cpp the entire file was replaced,
whereas for videoctrl.cpp there was enough shared logic that it was
kept, and the platform-specific bits were moved behind a Display class
that can have per-platform implementations. For cases where we need
additional private fields in the platform-specific classes, we use
a PIMPL pattern.

The *_js.cpp files with implementations are not included in this
commit, since they are closely tied to the Infinite Mac project, and
will live in its fork of DingusPPC.

[^1]: https://www.chromium.org/developers/design-documents/conventions-and-patterns-for-multi-platform-development/

Author: mihaip

CMakeLists.txt

@@ -1,20 +1,23 @@
 cmake_minimum_required(VERSION 3.1)
 project(dingusppc)
 
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
+include(PlatformGlob)
+
 set(CMAKE_CXX_STANDARD 20)
 
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin)
 set(LIBRARY_OUTPUT_PATH ${CMAKE_BINARY_DIR}/lib)
 
-if (NOT WIN32)
+if (NOT WIN32 AND NOT EMSCRIPTEN)
     find_package(SDL2 REQUIRED)
     include_directories(${SDL2_INCLUDE_DIRS})
     if (UNIX AND NOT APPLE)
         find_package (Threads)
     endif()
 
-else() # Windows build relies on vcpkg
+elseif (WIN32) # Windows build relies on vcpkg
     # pick up system wide vcpkg if exists
     if (DEFINED ENV{VCPKG_ROOT} AND EXISTS $ENV{VCPKG_ROOT}/scripts/buildsystems/vcpkg.cmake)
         message(STATUS "Using system vcpkg at $ENV{VCPKG_ROOT}")
@@ -89,11 +92,12 @@ add_subdirectory("${PROJECT_SOURCE_DIR}/machines/")
 add_subdirectory("${PROJECT_SOURCE_DIR}/utils/")
 add_subdirectory("${PROJECT_SOURCE_DIR}/thirdparty/loguru/")
 
-set(BUILD_TESTS OFF CACHE BOOL "Build Cubeb tests")
-set(BUILD_SHARED_LIBS OFF CACHE BOOL "Build shared libraries")
-set(BUILD_TOOLS OFF CACHE BOOL "Build Cubeb tools")
-
-add_subdirectory(thirdparty/cubeb EXCLUDE_FROM_ALL)
+if (NOT EMSCRIPTEN)
+    set(BUILD_TESTS OFF CACHE BOOL "Build Cubeb tests")
+    set(BUILD_SHARED_LIBS OFF CACHE BOOL "Build shared libraries")
+    set(BUILD_TOOLS OFF CACHE BOOL "Build Cubeb tools")
+    add_subdirectory(thirdparty/cubeb EXCLUDE_FROM_ALL)
+endif()
 
 set(CLI11_ROOT ${PROJECT_SOURCE_DIR}/thirdparty/CLI11)
 
@@ -107,10 +111,10 @@ include_directories("${PROJECT_SOURCE_DIR}"
                     "${PROJECT_SOURCE_DIR}/thirdparty/CLI11/"
                     "${PROJECT_SOURCE_DIR}/thirdparty/cubeb/include")
 
-file(GLOB SOURCES "${PROJECT_SOURCE_DIR}/*.cpp"
-                  "${PROJECT_SOURCE_DIR}/*.c"
-                  "${PROJECT_SOURCE_DIR}/*.hpp"
-                  "${PROJECT_SOURCE_DIR}/*.h")
+platform_glob(SOURCES "${PROJECT_SOURCE_DIR}/*.cpp"
+                      "${PROJECT_SOURCE_DIR}/*.c"
+                      "${PROJECT_SOURCE_DIR}/*.hpp"
+                      "${PROJECT_SOURCE_DIR}/*.h")
 
 file(GLOB TEST_SOURCES "${PROJECT_SOURCE_DIR}/cpu/ppc/test/*.cpp")
 
@@ -125,7 +129,7 @@ add_executable(dingusppc ${SOURCES} $<TARGET_OBJECTS:core>
 if (WIN32)
     target_link_libraries(dingusppc PRIVATE SDL2::SDL2 SDL2::SDL2main cubeb)
 elseif (EMSCRIPTEN)
-    target_link_libraries(dingusppc PRIVATE SDL2::SDL2 SDL2::SDL2main cubeb
+    target_link_libraries(dingusppc PRIVATE
                                     ${CMAKE_DL_LIBS} ${CMAKE_THREAD_LIBS_INIT}
                                     "-gsource-map"
                                     # 256 MB max for emulated Mac RAM, plus 32 MB of emulator overhead

cmake/PlatformGlob.cmake

@@ -0,0 +1,21 @@
+# Detect platform suffix
+if (EMSCRIPTEN)
+    set(PLATFORM_SUFFIX "_js$")
+else()
+    set(PLATFORM_SUFFIX "_sdl|_cubeb$")
+endif()
+
+# Function to perform a platform-specific glob
+function(platform_glob RESULT_VAR)
+    set(PLATFORM_SOURCES)
+    foreach(GLOB_PATTERN ${ARGN})
+        file(GLOB GLOB_RESULT ${GLOB_PATTERN})
+        foreach(FILE_PATH ${GLOB_RESULT})
+            get_filename_component(BASE_NAME ${FILE_PATH} NAME_WE)
+            if("${BASE_NAME}" MATCHES ${PLATFORM_SUFFIX} OR NOT "${BASE_NAME}" MATCHES "_js$|_sdl|_cubeb$")
+                list(APPEND PLATFORM_SOURCES ${FILE_PATH})
+            endif()
+        endforeach()
+    endforeach()
+    set(${RESULT_VAR} ${PLATFORM_SOURCES} PARENT_SCOPE)
+endfunction()

core/CMakeLists.txt

@@ -2,7 +2,11 @@ include_directories("${PROJECT_SOURCE_DIR}"
                     "${PROJECT_SOURCE_DIR}/thirdparty/loguru/"
                     )
 
-file(GLOB SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/*.cpp")
+platform_glob(SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/*.cpp")
 
 add_library(core OBJECT ${SOURCES})
-target_link_libraries(core PRIVATE SDL2::SDL2)
+if (EMSCRIPTEN)
+    target_link_libraries(core PRIVATE)
+else()
+    target_link_libraries(core PRIVATE SDL2::SDL2)
+endif()

core/hostevents.cpp renamed to core/hostevents_sdl.cpp

@@ -1,23 +1,30 @@
+list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
+include(PlatformGlob)
+
 include_directories("${PROJECT_SOURCE_DIR}"
                     "${PROJECT_SOURCE_DIR}/thirdparty/loguru/"
                    )
 
-file(GLOB SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/common/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/common/adb/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/common/i2c/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/common/ata/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/common/pci/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/common/scsi/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/ethernet/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/floppy/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/ioctrl/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/memctrl/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/serial/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/sound/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/storage/*.cpp"
-                  "${CMAKE_CURRENT_SOURCE_DIR}/video/*.cpp"
+platform_glob(SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/common/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/common/adb/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/common/i2c/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/common/ata/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/common/pci/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/common/scsi/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/ethernet/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/floppy/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/ioctrl/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/memctrl/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/serial/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/sound/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/storage/*.cpp"
+                      "${CMAKE_CURRENT_SOURCE_DIR}/video/*.cpp"
     )
 
 add_library(devices OBJECT ${SOURCES})
-target_link_libraries(devices PRIVATE cubeb SDL2::SDL2)
+if (EMSCRIPTEN)
+    target_link_libraries(devices PRIVATE)
+else()
+    target_link_libraries(devices PRIVATE cubeb SDL2::SDL2)
+endif()

devices/CMakeLists.txt

@@ -301,7 +301,7 @@ FloppyImgConverter* open_floppy_image(std::string& img_path)
     img_file.open(img_path, std::ios::in | std::ios::binary);
     if (img_file.fail()) {
         img_file.close();
-        LOG_F(ERROR, "Could not open specified floppy image!");
+        LOG_F(ERROR, "Could not open specified floppy image (%s)!", img_path.c_str());
         return nullptr;
     }
 

devices/floppy/floppyimg.cpp

@@ -34,25 +34,14 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #ifndef SOUND_SERVER_H
 #define SOUND_SERVER_H
 
-#include <cubeb/cubeb.h>
 #include <devices/common/hwcomponent.h>
 
-enum {
-    SND_SERVER_DOWN = 0,
-    SND_API_READY,
-    SND_SERVER_UP,
-    SND_STREAM_OPENED,
-    SND_STREAM_CLOSED
-};
-
+#include <memory>
 
 class SoundServer : public HWComponent {
 public:
-    SoundServer()  {
-        supports_types(HWCompType::SND_SERVER);
-        this->start();
-    };
-    ~SoundServer() { this->shutdown(); };
+    SoundServer();
+    ~SoundServer();
 
     int start();
     void shutdown();
@@ -61,10 +50,8 @@ class SoundServer : public HWComponent {
     void close_out_stream();
 
 private:
-    int status;                     /* server status */
-    cubeb *cubeb_ctx;
-
-    cubeb_stream *out_stream;
+    class Impl; // Holds private fields
+    std::unique_ptr<Impl> impl;
 };
 
 #endif /* SOUND_SERVER_H */

devices/sound/soundserver.h

@@ -29,60 +29,87 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 #include <objbase.h>
 #endif
 
+enum {
+    SND_SERVER_DOWN = 0,
+    SND_API_READY,
+    SND_SERVER_UP,
+    SND_STREAM_OPENED,
+    SND_STREAM_CLOSED
+};
+
+class SoundServer::Impl {
+public:
+    int status;                     /* server status */
+    cubeb *cubeb_ctx;
+
+    cubeb_stream *out_stream;
+};
+
+SoundServer::SoundServer(): impl(std::make_unique<Impl>())
+{
+    supports_types(HWCompType::SND_SERVER);
+    this->start();
+}
+
+SoundServer::~SoundServer()
+{
+    this->shutdown();
+}
+
 #if 0
 int SoundServer::start()
 {
     int err;
 
-    this->status = SND_SERVER_DOWN;
+    impl->status = SND_SERVER_DOWN;
 
-    this->soundio = soundio_create();
-    if (!this->soundio) {
+    impl->soundio = soundio_create();
+    if (!impl->soundio) {
         LOG_F(ERROR, "Sound Server: out of memory");
         return -1;
     }
 
-    if ((err = soundio_connect(this->soundio))) {
+    if ((err = soundio_connect(impl->soundio))) {
         LOG_F(ERROR, "Unable to connect to backend: %s", soundio_strerror(err));
         return -1;
     }
 
     LOG_F(INFO, "Connected to backend: %s", soundio_backend_name(soundio->current_backend));
 
-    soundio_flush_events(this->soundio);
+    soundio_flush_events(impl->soundio);
 
-    this->status = SND_API_READY;
+    impl->status = SND_API_READY;
 
-    this->out_dev_index = soundio_default_output_device_index(this->soundio);
-    if (this->out_dev_index < 0) {
+    impl->out_dev_index = soundio_default_output_device_index(impl->soundio);
+    if (impl->out_dev_index < 0) {
         LOG_F(ERROR, "Sound Server: no output device found");
         return -1;
     }
 
-    this->out_device = soundio_get_output_device(this->soundio, this->out_dev_index);
-    if (!this->out_device) {
+    impl->out_device = soundio_get_output_device(this->soundio, this->out_dev_index);
+    if (!impl->out_device) {
         LOG_F(ERROR, "Sound Server: out of memory");
         return -1;
     }
 
-    LOG_F(INFO, "Sound Server output device: %s", this->out_device->name);
+    LOG_F(INFO, "Sound Server output device: %s", impl->out_device->name);
 
-    this->status = SND_SERVER_UP;
+    impl->status = SND_SERVER_UP;
 
     return 0;
 }
 
 void SoundServer::shutdown()
 {
-    switch (this->status) {
+    switch (impl->status) {
     case SND_SERVER_UP:
-        soundio_device_unref(this->out_device);
+        soundio_device_unref(impl->out_device);
         /* fall through */
     case SND_API_READY:
-        soundio_destroy(this->soundio);
+        soundio_destroy(impl->soundio);
     }
 
-    this->status = SND_SERVER_DOWN;
+    impl->status = SND_SERVER_DOWN;
 
     LOG_F(INFO, "Sound Server shut down.");
 }
@@ -96,24 +123,24 @@ int SoundServer::start()
     CoInitialize(nullptr);
 #endif
 
-    this->status = SND_SERVER_DOWN;
+    impl->status = SND_SERVER_DOWN;
 
-    res = cubeb_init(&this->cubeb_ctx, "Dingus sound server", NULL);
+    res = cubeb_init(&impl->cubeb_ctx, "Dingus sound server", NULL);
     if (res != CUBEB_OK) {
         LOG_F(ERROR, "Could not initialize Cubeb library");
         return -1;
     }
 
-    LOG_F(INFO, "Connected to backend: %s", cubeb_get_backend_id(this->cubeb_ctx));
+    LOG_F(INFO, "Connected to backend: %s", cubeb_get_backend_id(impl->cubeb_ctx));
 
-    this->status = SND_API_READY;
+    impl->status = SND_API_READY;
 
     return 0;
 }
 
 void SoundServer::shutdown()
 {
-    switch (this->status) {
+    switch (impl->status) {
     case SND_STREAM_OPENED:
         close_out_stream();
         /* fall through */
@@ -122,10 +149,10 @@ void SoundServer::shutdown()
     case SND_SERVER_UP:
         /* fall through */
     case SND_API_READY:
-        cubeb_destroy(this->cubeb_ctx);
+        cubeb_destroy(impl->cubeb_ctx);
     }
 
-    this->status = SND_SERVER_DOWN;
+    impl->status = SND_SERVER_DOWN;
 
     LOG_F(INFO, "Sound Server shut down.");
 }
@@ -189,15 +216,15 @@ int SoundServer::open_out_stream(uint32_t sample_rate, void *user_data)
     params.layout = CUBEB_LAYOUT_STEREO;
     params.prefs = CUBEB_STREAM_PREF_NONE;
 
-    res = cubeb_get_min_latency(this->cubeb_ctx, &params, &latency_frames);
+    res = cubeb_get_min_latency(impl->cubeb_ctx, &params, &latency_frames);
     if (res != CUBEB_OK) {
         LOG_F(ERROR, "Could not get minimum latency, error: %d", res);
         return -1;
     } else {
         LOG_F(9, "Minimum sound latency: %d frames", latency_frames);
     }
 
-    res = cubeb_stream_init(this->cubeb_ctx, &this->out_stream, "SndOut stream",
+    res = cubeb_stream_init(impl->cubeb_ctx, &impl->out_stream, "SndOut stream",
                             NULL, NULL, NULL, &params, latency_frames,
                             sound_out_callback, status_callback, user_data);
     if (res != CUBEB_OK) {
@@ -207,20 +234,20 @@ int SoundServer::open_out_stream(uint32_t sample_rate, void *user_data)
 
     LOG_F(9, "Sound output stream opened.");
 
-    this->status = SND_STREAM_OPENED;
+    impl->status = SND_STREAM_OPENED;
 
     return 0;
 }
 
 int SoundServer::start_out_stream()
 {
-    return cubeb_stream_start(this->out_stream);
+    return cubeb_stream_start(impl->out_stream);
 }
 
 void SoundServer::close_out_stream()
 {
-    cubeb_stream_stop(this->out_stream);
-    cubeb_stream_destroy(this->out_stream);
-    this->status = SND_STREAM_CLOSED;
+    cubeb_stream_stop(impl->out_stream);
+    cubeb_stream_destroy(impl->out_stream);
+    impl->status = SND_STREAM_CLOSED;
     LOG_F(9, "Sound output stream closed.");
 }