feat: add linux desktop support.

.github/workflows/example_build.yml

@@ -0,0 +1,121 @@
+name: example build
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+  workflow_dispatch:
+
+env:
+  nodeVersion: "16"
+  cmakeVersion: "3.22.x"
+  flutterVersion: "2.5.3"
+
+jobs:
+  build_android-app_in_macos:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+      # Set up the bridge compilation environment
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ env.nodeVersion }}
+      - uses: jwlawson/actions-setup-cmake@v1.11
+        with:
+          cmake-version: ${{ env.cmakeVersion }}
+      - run: npm i
+      - run: npm run build:bridge:android:release
+
+      # Install Flutter SDK
+      - uses: subosito/flutter-action@v1
+        with:
+          flutter-version: ${{ env.flutterVersion }}
+      - run: flutter doctor -v
+
+      - name: android app build
+        run: |
+          cd kraken/
+          flutter pub get
+          cd example/
+          flutter build apk --release
+
+  build_ios-app_in_macos:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ env.nodeVersion }}
+      - uses: jwlawson/actions-setup-cmake@v1.11
+        with:
+          cmake-version: ${{ env.cmakeVersion }}
+      - run: npm i
+      - run: npm run build:bridge:ios:release
+
+      - uses: subosito/flutter-action@v1
+        with:
+          flutter-version: ${{ env.flutterVersion }}
+      - run: flutter doctor -v
+
+      - name: ios app build
+        run: |
+          cd kraken/
+          flutter pub get
+          cd example/
+          flutter build ios --release --no-codesign
+
+  build_macos-app_in_macos:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ env.nodeVersion }}
+      - uses: jwlawson/actions-setup-cmake@v1.11
+        with:
+          cmake-version: ${{ env.cmakeVersion }}
+      - run: npm i
+      - run: npm run build:bridge:macos:release
+
+      - uses: subosito/flutter-action@v1
+        with:
+          flutter-version: ${{ env.flutterVersion }}
+      - run: flutter config --enable-macos-desktop
+      - run: flutter doctor -v
+
+      - name: macos app build
+        run: |
+          cd kraken/
+          flutter pub get
+          cd example/
+          flutter build macos --release
+
+  build_linux-app_in_ubuntu:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v2
+        with:
+          node-version: ${{ env.nodeVersion }}
+      - uses: jwlawson/actions-setup-cmake@v1.11
+        with:
+          cmake-version: ${{ env.cmakeVersion }}
+
+      - run: npm i
+      - run: npm run build:bridge:linux:release
+
+      - uses: subosito/flutter-action@v1
+        with:
+          flutter-version: ${{ env.flutterVersion }}
+      - run: flutter config --enable-linux-desktop
+      - run: |
+          sudo apt-get update
+          sudo apt-get install ninja-build pkg-config libgtk-3-dev -y
+      - run: flutter doctor -v
+      - name: linux app build
+        run: |
+          cd kraken/
+          flutter pub get
+          cd example/
+          flutter build linux --release

bridge/CMakeLists.txt

@@ -65,6 +65,9 @@ set(QUICKJS_PUBLIC_HEADERS
   ${CMAKE_CURRENT_SOURCE_DIR}/third_party/quickjs/quickjs-opcode.h
 )
 
+if (${CMAKE_SYSTEM_NAME} STREQUAL "Linux")
+  add_compile_options(-fPIC)
+endif()
 
 if (ENABLE_ASAN)
   add_compile_options(-fsanitize=address -fno-omit-frame-pointer -O1)

kraken/android/build.gradle

@@ -8,7 +8,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:4.1.0'
     }
 }
 

kraken/android/gradle/wrapper/gradle-wrapper.properties

@@ -2,4 +2,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip

kraken/example/android/build.gradle

@@ -5,7 +5,7 @@ buildscript {
     }
 
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.5.0'
+        classpath 'com.android.tools.build:gradle:4.1.0'
     }
 }
 

kraken/example/android/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip

kraken/example/linux/.gitignore

@@ -0,0 +1 @@
+flutter/ephemeral

kraken/example/linux/CMakeLists.txt

@@ -0,0 +1,116 @@
+cmake_minimum_required(VERSION 3.10)
+project(runner LANGUAGES CXX)
+
+set(BINARY_NAME "kraken_example")
+set(APPLICATION_ID "com.example.kraken")
+
+cmake_policy(SET CMP0063 NEW)
+
+set(CMAKE_INSTALL_RPATH "$ORIGIN/lib")
+
+# Root filesystem for cross-building.
+if(FLUTTER_TARGET_PLATFORM_SYSROOT)
+  set(CMAKE_SYSROOT ${FLUTTER_TARGET_PLATFORM_SYSROOT})
+  set(CMAKE_FIND_ROOT_PATH ${CMAKE_SYSROOT})
+  set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+  set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+  set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+  set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+endif()
+
+# Configure build options.
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+  set(CMAKE_BUILD_TYPE "Debug" CACHE
+    STRING "Flutter build mode" FORCE)
+  set_property(CACHE CMAKE_BUILD_TYPE PROPERTY STRINGS
+    "Debug" "Profile" "Release")
+endif()
+
+# Compilation settings that should be applied to most targets.
+function(APPLY_STANDARD_SETTINGS TARGET)
+  target_compile_features(${TARGET} PUBLIC cxx_std_14)
+  target_compile_options(${TARGET} PRIVATE -Wall -Werror)
+  target_compile_options(${TARGET} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:-O3>")
+  target_compile_definitions(${TARGET} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:NDEBUG>")
+endfunction()
+
+set(FLUTTER_MANAGED_DIR "${CMAKE_CURRENT_SOURCE_DIR}/flutter")
+
+# Flutter library and tool build rules.
+add_subdirectory(${FLUTTER_MANAGED_DIR})
+
+# System-level dependencies.
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(GTK REQUIRED IMPORTED_TARGET gtk+-3.0)
+
+add_definitions(-DAPPLICATION_ID="${APPLICATION_ID}")
+
+# Application build
+add_executable(${BINARY_NAME}
+  "main.cc"
+  "my_application.cc"
+  "${FLUTTER_MANAGED_DIR}/generated_plugin_registrant.cc"
+)
+apply_standard_settings(${BINARY_NAME})
+target_link_libraries(${BINARY_NAME} PRIVATE flutter)
+target_link_libraries(${BINARY_NAME} PRIVATE PkgConfig::GTK)
+add_dependencies(${BINARY_NAME} flutter_assemble)
+# Only the install-generated bundle's copy of the executable will launch
+# correctly, since the resources must in the right relative locations. To avoid
+# people trying to run the unbundled copy, put it in a subdirectory instead of
+# the default top-level location.
+set_target_properties(${BINARY_NAME}
+  PROPERTIES
+  RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/intermediates_do_not_run"
+)
+
+# Generated plugin build rules, which manage building the plugins and adding
+# them to the application.
+include(flutter/generated_plugins.cmake)
+
+
+# === Installation ===
+# By default, "installing" just makes a relocatable bundle in the build
+# directory.
+set(BUILD_BUNDLE_DIR "${PROJECT_BINARY_DIR}/bundle")
+if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
+  set(CMAKE_INSTALL_PREFIX "${BUILD_BUNDLE_DIR}" CACHE PATH "..." FORCE)
+endif()
+
+# Start with a clean build bundle directory every time.
+install(CODE "
+  file(REMOVE_RECURSE \"${BUILD_BUNDLE_DIR}/\")
+  " COMPONENT Runtime)
+
+set(INSTALL_BUNDLE_DATA_DIR "${CMAKE_INSTALL_PREFIX}/data")
+set(INSTALL_BUNDLE_LIB_DIR "${CMAKE_INSTALL_PREFIX}/lib")
+
+install(TARGETS ${BINARY_NAME} RUNTIME DESTINATION "${CMAKE_INSTALL_PREFIX}"
+  COMPONENT Runtime)
+
+install(FILES "${FLUTTER_ICU_DATA_FILE}" DESTINATION "${INSTALL_BUNDLE_DATA_DIR}"
+  COMPONENT Runtime)
+
+install(FILES "${FLUTTER_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+  COMPONENT Runtime)
+
+if(PLUGIN_BUNDLED_LIBRARIES)
+  install(FILES "${PLUGIN_BUNDLED_LIBRARIES}"
+    DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+    COMPONENT Runtime)
+endif()
+
+# Fully re-copy the assets directory on each build to avoid having stale files
+# from a previous install.
+set(FLUTTER_ASSET_DIR_NAME "flutter_assets")
+install(CODE "
+  file(REMOVE_RECURSE \"${INSTALL_BUNDLE_DATA_DIR}/${FLUTTER_ASSET_DIR_NAME}\")
+  " COMPONENT Runtime)
+install(DIRECTORY "${PROJECT_BUILD_DIR}/${FLUTTER_ASSET_DIR_NAME}"
+  DESTINATION "${INSTALL_BUNDLE_DATA_DIR}" COMPONENT Runtime)
+
+# Install the AOT library on non-Debug builds only.
+if(NOT CMAKE_BUILD_TYPE MATCHES "Debug")
+  install(FILES "${AOT_LIBRARY}" DESTINATION "${INSTALL_BUNDLE_LIB_DIR}"
+    COMPONENT Runtime)
+endif()

kraken/example/linux/flutter/CMakeLists.txt

@@ -0,0 +1,87 @@
+cmake_minimum_required(VERSION 3.10)
+
+set(EPHEMERAL_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ephemeral")
+
+# Configuration provided via flutter tool.
+include(${EPHEMERAL_DIR}/generated_config.cmake)
+
+# TODO: Move the rest of this into files in ephemeral. See
+# https://github.com/flutter/flutter/issues/57146.
+
+# Serves the same purpose as list(TRANSFORM ... PREPEND ...),
+# which isn't available in 3.10.
+function(list_prepend LIST_NAME PREFIX)
+    set(NEW_LIST "")
+    foreach(element ${${LIST_NAME}})
+        list(APPEND NEW_LIST "${PREFIX}${element}")
+    endforeach(element)
+    set(${LIST_NAME} "${NEW_LIST}" PARENT_SCOPE)
+endfunction()
+
+# === Flutter Library ===
+# System-level dependencies.
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(GTK REQUIRED IMPORTED_TARGET gtk+-3.0)
+pkg_check_modules(GLIB REQUIRED IMPORTED_TARGET glib-2.0)
+pkg_check_modules(GIO REQUIRED IMPORTED_TARGET gio-2.0)
+
+set(FLUTTER_LIBRARY "${EPHEMERAL_DIR}/libflutter_linux_gtk.so")
+
+# Published to parent scope for install step.
+set(FLUTTER_LIBRARY ${FLUTTER_LIBRARY} PARENT_SCOPE)
+set(FLUTTER_ICU_DATA_FILE "${EPHEMERAL_DIR}/icudtl.dat" PARENT_SCOPE)
+set(PROJECT_BUILD_DIR "${PROJECT_DIR}/build/" PARENT_SCOPE)
+set(AOT_LIBRARY "${PROJECT_DIR}/build/lib/libapp.so" PARENT_SCOPE)
+
+list(APPEND FLUTTER_LIBRARY_HEADERS
+  "fl_basic_message_channel.h"
+  "fl_binary_codec.h"
+  "fl_binary_messenger.h"
+  "fl_dart_project.h"
+  "fl_engine.h"
+  "fl_json_message_codec.h"
+  "fl_json_method_codec.h"
+  "fl_message_codec.h"
+  "fl_method_call.h"
+  "fl_method_channel.h"
+  "fl_method_codec.h"
+  "fl_method_response.h"
+  "fl_plugin_registrar.h"
+  "fl_plugin_registry.h"
+  "fl_standard_message_codec.h"
+  "fl_standard_method_codec.h"
+  "fl_string_codec.h"
+  "fl_value.h"
+  "fl_view.h"
+  "flutter_linux.h"
+)
+list_prepend(FLUTTER_LIBRARY_HEADERS "${EPHEMERAL_DIR}/flutter_linux/")
+add_library(flutter INTERFACE)
+target_include_directories(flutter INTERFACE
+  "${EPHEMERAL_DIR}"
+)
+target_link_libraries(flutter INTERFACE "${FLUTTER_LIBRARY}")
+target_link_libraries(flutter INTERFACE
+  PkgConfig::GTK
+  PkgConfig::GLIB
+  PkgConfig::GIO
+)
+add_dependencies(flutter flutter_assemble)
+
+# === Flutter tool backend ===
+# _phony_ is a non-existent file to force this command to run every time,
+# since currently there's no way to get a full input/output list from the
+# flutter tool.
+add_custom_command(
+  OUTPUT ${FLUTTER_LIBRARY} ${FLUTTER_LIBRARY_HEADERS}
+    ${CMAKE_CURRENT_BINARY_DIR}/_phony_
+  COMMAND ${CMAKE_COMMAND} -E env
+    ${FLUTTER_TOOL_ENVIRONMENT}
+    "${FLUTTER_ROOT}/packages/flutter_tools/bin/tool_backend.sh"
+      ${FLUTTER_TARGET_PLATFORM} ${CMAKE_BUILD_TYPE}
+  VERBATIM
+)
+add_custom_target(flutter_assemble DEPENDS
+  "${FLUTTER_LIBRARY}"
+  ${FLUTTER_LIBRARY_HEADERS}
+)

kraken/example/linux/flutter/generated_plugin_registrant.cc

@@ -0,0 +1,13 @@
+//
+//  Generated file. Do not edit.
+//
+
+#include "generated_plugin_registrant.h"
+
+#include <kraken/kraken_plugin.h>
+
+void fl_register_plugins(FlPluginRegistry* registry) {
+  g_autoptr(FlPluginRegistrar) kraken_registrar =
+      fl_plugin_registry_get_registrar_for_plugin(registry, "KrakenPlugin");
+  kraken_plugin_register_with_registrar(kraken_registrar);
+}

kraken/example/linux/flutter/generated_plugin_registrant.h

@@ -0,0 +1,13 @@
+//
+//  Generated file. Do not edit.
+//
+
+#ifndef GENERATED_PLUGIN_REGISTRANT_
+#define GENERATED_PLUGIN_REGISTRANT_
+
+#include <flutter_linux/flutter_linux.h>
+
+// Registers Flutter plugins.
+void fl_register_plugins(FlPluginRegistry* registry);
+
+#endif  // GENERATED_PLUGIN_REGISTRANT_