[master < T0792-MG] Add wasm compilation target to mgclient

.github/workflows/ci.yml

@@ -128,3 +128,19 @@ jobs:
           cmake .. -G "MinGW Makefiles" -DBUILD_TESTING=ON -DBUILD_TESTING_INTEGRATION=ON -DC_WARNINGS_AS_ERRORS=ON -DCPP_WARNINGS_AS_ERRORS=ON
           cmake --build .
           ctest --verbose -R "allocator|value|example_basic|integration_basic"
+
+  build_and_test_linux_wasm:
+    strategy:
+     matrix:
+        platform: [ubuntu-18.04]
+    runs-on: ${{ matrix.platform }}
+    steps:
+      - name: Set-up repository
+        uses: actions/checkout@v2
+
+      - name: Build with clang
+        run: |
+          mkdir build 
+          cd build
+          cmake .. -DCMAKE_BUILD_TYPE=Release -DC_WARNINGS_AS_ERRORS=ON -DWASM=ON
+          make

.gitignore

@@ -13,3 +13,6 @@ tool/generated/
 
 # Doxygen output files.
 html/
+
+# emsdk folder pulled from wasm/install_deps.sh
+wasm/emsdk

CMakeLists.txt

@@ -14,13 +14,23 @@
 
 cmake_minimum_required(VERSION 3.8)
 
-project(mgclient VERSION 1.3.0)
+if(WASM) 
+    execute_process(COMMAND ${CMAKE_SOURCE_DIR}/wasm/install_deps.sh)
+    set(CMAKE_TOOLCHAIN_FILE "${CMAKE_SOURCE_DIR}/wasm/emsdk/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake")
+endif()
+
+project(mgclient VERSION 1.2.0)
 # Minor version increase can also mean ABI incompatibility with previous
 # versions. IMPORTANT: Take care of the SO version manually.
 set(mgclient_SOVERSION 2)
+set(WASM OFF CACHE BOOL "Compile mgclient for wasm")
 add_definitions(-DMGCLIENT_VERSION="${mgclient_VERSION}")
 
 # Deal with the operating system.
+if((NOT UNIX) AND EMSCRIPTEN)
+    message(FATAL_ERROR "WASM build is only supported in Linux")
+endif()
+
 if(WIN32)
     message(STATUS "ON WINDOWS BUILD")
     set(MGCLIENT_ON_WINDOWS TRUE)
@@ -29,14 +39,16 @@ if(WIN32)
     # "lib;" breaks gtest lib referencing.
     set(MGCLIENT_FIND_LIBRARY_PREFIXES "lib")
 elseif(UNIX AND NOT APPLE)
-    if(CMAKE_SYSTEM_NAME STREQUAL "Linux")
+    if(EMSCRIPTEN)
+        message(STATUS "ON LINUX WASM BUILD")
+    elseif(CMAKE_SYSTEM_NAME STREQUAL "Linux")
         message(STATUS "ON LINUX BUILD")
-        set(MGCLIENT_ON_LINUX TRUE)
-        add_definitions(-DMGCLIENT_ON_LINUX)
-        set(MGCLIENT_FIND_LIBRARY_PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
-    else()
+    else() 
         message(FATAL_ERROR "Unsupported operating system. Please create issue or contribute!")
     endif()
+    set(MGCLIENT_ON_LINUX TRUE)
+    add_definitions(-DMGCLIENT_ON_LINUX)
+    set(MGCLIENT_FIND_LIBRARY_PREFIXES "${CMAKE_FIND_LIBRARY_PREFIXES}")
 elseif(APPLE)
     message(STATUS "ON APPLE BUILD")
     set(MGCLIENT_ON_APPLE TRUE)
@@ -79,6 +91,14 @@ set_project_c_warnings(project_c_warnings)
 add_library(project_cpp_warnings INTERFACE)
 set_project_cpp_warnings(project_cpp_warnings)
 
+if(EMSCRIPTEN)
+   # same as project_c_warnings but without -O3. In the future we should
+   # experiment and switch to O3. because it reduces the js output size
+   # significantly.
+   set(CMAKE_C_FLAGS_DEBUG "-g -O0 -Wall -Wextra -Wpedantic -std=gnu11")
+   set(CMAKE_C_FLAGS_RELEASE "-O2 -DNDEBUG -Wall -Wextra -Wpedantic -std=gnu11")
+endif()
+
 # Set default build type to 'Release'
 if(NOT CMAKE_BUILD_TYPE)
     set(CMAKE_BUILD_TYPE "Release")

README.md

@@ -126,6 +126,12 @@ cd build
 cmake .. -G "MinGW Makefiles"
 cmake --build . --target install
 ```
+## Building WASM (linux only)
+Compiling `mgclient` for wasm requires the Emscripten sdk. This is automated in the following steps:
+  1. mkdir build && cd build
+  2. cmake .. -DWASM=ON
+  3. make
+Now there should be an `mgclient.js` and an `mgclient.wasm` found in `mgclient/build/`
 
 ## Using the library
 

include/mgclient.h

@@ -15,7 +15,12 @@
 #ifndef MGCLIENT_MGCLIENT_H
 #define MGCLIENT_MGCLIENT_H
 
+#ifdef __EMSCRIPTEN__
+#define MGCLIENT_EXPORT EMSCRIPTEN_KEEPALIVE
+#include "emscripten.h"
+#else
 #include "mgclient-export.h"
+#endif
 
 #ifdef __cplusplus
 extern "C" {
@@ -1127,7 +1132,9 @@ MGCLIENT_EXPORT void mg_point_3d_destroy(mg_point_3d *point_3d);
 /// the server.
 enum mg_sslmode {
   MG_SSLMODE_DISABLE,  ///< Only try a non-SSL connection.
+#ifndef __EMSCRIPTEN__
   MG_SSLMODE_REQUIRE,  ///< Only try a SSL connection.
+#endif
 };
 
 /// An object encapsulating a Bolt session.

src/CMakeLists.txt

@@ -35,58 +35,84 @@ else()
     message(FATAL_ERROR "Operating system undefined.")
 endif()
 
-find_package(OpenSSL REQUIRED)
+if(EMSCRIPTEN)
+    list(APPEND mgclient_src_files mgwasm.c)
+    add_executable(mgclient ${mgclient_src_files})
+    set_target_properties(mgclient PROPERTIES LINK_FLAGS "-s ASYNCIFY=1 -s MODULARIZE -s EXPORT_NAME=\"load_mgclient\" --shared-memory --no-entry -s USE_PTHREADS=1 -s WEBSOCKET_SUBPROTOCOL=\"binary\" -s EXPORTED_RUNTIME_METHODS=\"ccall, cwrap, getValue, setValue, UTF8ToString, allocateUTF8\"")
 
-include(GenerateExportHeader)
+    target_include_directories(mgclient
+            PRIVATE
+            "${PROJECT_SOURCE_DIR}/src"
+            PUBLIC
+            "${PROJECT_SOURCE_DIR}/include"
+            "${CMAKE_CURRENT_BINARY_DIR}")
+else()
+    find_package(OpenSSL REQUIRED)
+    include(GenerateExportHeader)
 
-add_library(mgclient-static STATIC ${mgclient_src_files})
-set_target_properties(mgclient-static PROPERTIES
-        OUTPUT_NAME mgclient)
-target_compile_definitions(mgclient-static PUBLIC MGCLIENT_STATIC_DEFINE)
-target_include_directories(mgclient-static
-        PRIVATE
-        "${PROJECT_SOURCE_DIR}/src"
-        PUBLIC
-        "${PROJECT_SOURCE_DIR}/include"
-        "${CMAKE_CURRENT_BINARY_DIR}"
-        "${OPENSSL_INCLUDE_DIR}")
-target_link_libraries(mgclient-static
-        PRIVATE
-        ${OPENSSL_LIBRARIES} project_options project_c_warnings)
-if(MGCLIENT_ON_WINDOWS)
-    target_link_libraries(mgclient-static PUBLIC ws2_32)
-endif()
+    add_library(mgclient-static STATIC ${mgclient_src_files})
 
-add_library(mgclient-shared SHARED ${mgclient_src_files})
-set_target_properties(mgclient-shared PROPERTIES
-        OUTPUT_NAME mgclient
-        SOVERSION ${mgclient_SOVERSION}
-        C_VISIBILITY_PRESET hidden)
-target_include_directories(mgclient-shared
-        PRIVATE
-        "${PROJECT_SOURCE_DIR}/src"
-        PUBLIC
-        "${PROJECT_SOURCE_DIR}/include"
-        "${CMAKE_CURRENT_BINARY_DIR}"
-        "${OPENSSL_INCLUDE_DIR}")
-target_link_libraries(mgclient-shared PRIVATE ${OPENSSL_LIBRARIES})
-if(MGCLIENT_ON_WINDOWS)
-    target_link_libraries(mgclient-shared PUBLIC ws2_32)
-endif()
+    generate_export_header(mgclient-static
+            BASE_NAME "mgclient"
+            EXPORT_FILE_NAME "mgclient-export.h")
+
+    set_target_properties(mgclient-static PROPERTIES
+            OUTPUT_NAME mgclient)
+    target_compile_definitions(mgclient-static PUBLIC MGCLIENT_STATIC_DEFINE)
+    target_include_directories(mgclient-static
+            PRIVATE
+            "${PROJECT_SOURCE_DIR}/src"
+            PUBLIC
+            "${PROJECT_SOURCE_DIR}/include"
+            "${CMAKE_CURRENT_BINARY_DIR}"
+            "${OPENSSL_INCLUDE_DIR}")
+    target_link_libraries(mgclient-static
+            PRIVATE
+            ${OPENSSL_LIBRARIES} project_options project_c_warnings)
+
+    if(MGCLIENT_ON_WINDOWS)
+        target_link_libraries(mgclient-static PUBLIC ws2_32)
+    endif()
 
-generate_export_header(mgclient-shared
-        BASE_NAME "mgclient"
-        EXPORT_FILE_NAME "mgclient-export.h")
+    add_library(mgclient-shared SHARED ${mgclient_src_files})
 
-include(GNUInstallDirs)
+    generate_export_header(mgclient-shared
+            BASE_NAME "mgclient"
+            EXPORT_FILE_NAME "mgclient-export.h")
 
-install(TARGETS mgclient-static mgclient-shared
-        ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
-        RUNTIME DESTINATION ${CMAKE_INSTALL_LIBDIR})
-install(DIRECTORY
-        "${PROJECT_SOURCE_DIR}/include/"
-        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
-install(FILES
-        "${CMAKE_CURRENT_BINARY_DIR}/mgclient-export.h"
-        DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+    set_target_properties(mgclient-shared PROPERTIES
+            OUTPUT_NAME mgclient
+            SOVERSION ${mgclient_SOVERSION}
+            C_VISIBILITY_PRESET hidden)
+    target_include_directories(mgclient-shared
+            PRIVATE
+            "${PROJECT_SOURCE_DIR}/src"
+            PUBLIC
+            "${PROJECT_SOURCE_DIR}/include"
+            "${CMAKE_CURRENT_BINARY_DIR}"
+            "${OPENSSL_INCLUDE_DIR}")
+    target_link_libraries(mgclient-shared
+            PRIVATE
+            ${OPENSSL_LIBRARIES} project_options project_c_warnings)
+
+    if(MGCLIENT_ON_WINDOWS)
+        target_link_libraries(mgclient-shared PUBLIC ws2_32)
+    endif()
+
+    generate_export_header(mgclient-shared
+            BASE_NAME "mgclient"
+            EXPORT_FILE_NAME "mgclient-export.h")
+
+    include(GNUInstallDirs)
+
+    install(TARGETS mgclient-static mgclient-shared
+            ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+            LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+            RUNTIME DESTINATION ${CMAKE_INSTALL_LIBDIR})
+    install(DIRECTORY
+            "${PROJECT_SOURCE_DIR}/include/"
+            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+    install(FILES
+            "${CMAKE_CURRENT_BINARY_DIR}/mgclient-export.h"
+            DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
+endif()

src/linux/mgsocket.c

@@ -12,18 +12,25 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include "mgsocket.h"
+
+#include <stdlib.h>
 #include <string.h>
 
 #include "mgcommon.h"
-#include "mgsocket.h"
 
-#define MG_RETRY_ON_EINTR(expression)          \
-  __extension__({                              \
-    long result;                               \
-    do {                                       \
-      result = (long)(expression);             \
-    } while (result == -1L && errno == EINTR); \
-    result;                                    \
+#ifdef __EMSCRIPTEN__
+#include "emscripten.h"
+#include "mgwasm.h"
+#endif
+
+#define MG_RETRY_ON_EINTR(expression)            \
+  __extension__({                                \
+    long result;                                 \
+    do {                                         \
+      result = (long)(expression);               \
+    } while (result == -1L && (errno == EINTR)); \
+    result;                                      \
   })
 
 // Please refer to https://man7.org/linux/man-pages/man2 for more details about
@@ -47,14 +54,32 @@ int mg_socket_create_handle_error(int sock, mg_session *session) {
   return MG_SUCCESS;
 }
 
+static int mg_socket_test_status_is_error(long status) {
+#ifdef __EMSCRIPTEN__
+  if (status == -1L && errno != EINPROGRESS) {
+#else
+  if (status == -1L) {
+#endif
+    return 1;
+  }
+  return 0;
+}
+
 int mg_socket_connect(int sock, const struct sockaddr *addr,
                       socklen_t addrlen) {
   long status = MG_RETRY_ON_EINTR(connect(sock, addr, addrlen));
-  if (status == -1L) {
+  if (mg_socket_test_status_is_error(status)) {
+    return MG_ERROR_SOCKET;
+  }
+#ifdef __EMSCRIPTEN__
+  if (mg_wasm_suspend_until_ready_to_write(sock) == -1) {
     return MG_ERROR_SOCKET;
   }
+#endif
+
   return MG_SUCCESS;
 }
+
 int mg_socket_connect_handle_error(int *sock, int status, mg_session *session) {
   if (status != MG_SUCCESS) {
     mg_session_set_error(session, "couldn't connect to host: %s",
@@ -69,6 +94,11 @@ int mg_socket_connect_handle_error(int *sock, int status, mg_session *session) {
 }
 
 int mg_socket_options(int sock, mg_session *session) {
+#ifdef __EMSCRIPTEN__
+  (void)sock;
+  (void)session;
+  return MG_SUCCESS;
+#else
   struct {
     int level;
     int optname;
@@ -100,6 +130,7 @@ int mg_socket_options(int sock, mg_session *session) {
     }
   }
   return MG_SUCCESS;
+#endif
 }
 
 ssize_t mg_socket_send(int sock, const void *buf, int len) {