Windows & Linux

info

This guide was written for flutter_rust_bridge v1, thus some content may be outdated. The quickest approach to integrate is to follow the one-click approach in flutter_rust_bridge's quickstart page.

Windows and Linux both use CMake for their build system, so this page will walk you through setting up CMake for Windows/Linux.

Also, this page will introduce the windows & linux build script to compile your Rust library to these platforms.

CMake

CMake happens to be by far the easiest build process to set up of of all the Flutter supported platforms.

Replace all instances of library_name below with your library name. Also, replace other variables (i.e. YourGitHubAccount and repo_name) as needed.

Linux CMakeLists.txt (/packages/flutter_library_name/linux/CMakeLists.txt)

set(LibraryVersion "library_name-v0.0.0") # generated; do not edit

# The Flutter tooling requires that developers have CMake 3.10 or later
# installed. You should not increase this version, as doing so will cause
# the plugin to fail to compile for some customers of the plugin.
cmake_minimum_required(VERSION 3.10)

# Project-level configuration.
set(PROJECT_NAME "flutter_library_name")
project(${PROJECT_NAME} LANGUAGES CXX)

# Download the binaries if they are not already present.
set(LibRoot "${CMAKE_CURRENT_SOURCE_DIR}/${LibraryVersion}")
set(ArchivePath "${LibRoot}.tar.gz")
if(NOT EXISTS ${ArchivePath})
  file(DOWNLOAD
    "https://github.com/YourGitHubAccount/repo_name/releases/download/${LibraryVersion}/other.tar.gz"
    ${ArchivePath}
    TLS_VERIFY ON
  )
endif()

# Extract the binaries, overriding any already present.
file(REMOVE_RECURSE ${LibRoot})
file(MAKE_DIRECTORY ${LibRoot})
execute_process(
  COMMAND ${CMAKE_COMMAND} -E tar xzf ${ArchivePath}
  WORKING_DIRECTORY ${LibRoot}
)

# List of absolute paths to libraries that should be bundled with the plugin.
# This list could contain prebuilt libraries, or libraries created by an
# external build triggered from this build file.
set(flutter_library_name_bundled_libraries
  "${LibRoot}/${FLUTTER_TARGET_PLATFORM}/liblibrary_name.so"
  PARENT_SCOPE
)

Windows CMakeLists.txt (/packages/flutter_library_name/windows/CMakeLists.txt)

set(LibraryVersion "library_name-v0.0.0") # generated; do not edit

# TODO Remove this workaround once Flutter supports Windows ARM.
# https://github.com/flutter/flutter/issues/116196
set(FLUTTER_TARGET_PLATFORM windows-x64)

# The Flutter tooling requires that developers have a version of Visual Studio
# installed that includes CMake 3.14 or later. You should not increase this
# version, as doing so will cause the plugin to fail to compile for some
# customers of the plugin.
cmake_minimum_required(VERSION 3.14)

# Project-level configuration.
set(PROJECT_NAME "flutter_library_name")
project(${PROJECT_NAME} LANGUAGES CXX)

# Download the binaries if they are not already present.
set(LibRoot "${CMAKE_CURRENT_SOURCE_DIR}/${LibraryVersion}")
set(ArchivePath "${LibRoot}.tar.gz")
if(NOT EXISTS ${ArchivePath})
  file(DOWNLOAD
    "https://github.com/YourGitHubAccount/repo_name/releases/download/${LibraryVersion}/other.tar.gz"
    ${ArchivePath}
    TLS_VERIFY ON
  )
endif()

# Extract the binaries, overriding any already present.
file(REMOVE_RECURSE ${LibRoot})
file(MAKE_DIRECTORY ${LibRoot})
execute_process(
  COMMAND ${CMAKE_COMMAND} -E tar xzf ${ArchivePath}
  WORKING_DIRECTORY ${LibRoot}
)

# List of absolute paths to libraries that should be bundled with the plugin.
# This list could contain prebuilt libraries, or libraries created by an
# external build triggered from this build file.
set(flutter_library_name_bundled_libraries
  "${LibRoot}/${FLUTTER_TARGET_PLATFORM}/library_name.dll"
  PARENT_SCOPE
)

Platform-Specific Peculiarities

There exists a few differences between the Linux and Windows CMakeLists.txts:

1. The minimum CMake version supported
2. At the time of writing, Windows CMake does not yet have a builtin FLUTTER_TARGET_PLATFORM variable; thus, we need to define a dummy version of the variable. See here for updates on this issue
3. On linux, dynamic library names follow the form of liblibrary_name.so and on Windows, dynamic library names follow the form of library_name.dll

.gitignore

If you choose to have a .gitignore in your linux/ and windows/ directories, here is what the author of this page uses:

# Set up as allowlist
*

# Allowed files
!.gitignore
!CMakeLists.txt

Build Script (/scripts/build-other.sh)

Replace library_name below as needed.

#!/bin/bash

# Setup
BUILD_DIR=platform-build
mkdir $BUILD_DIR
cd $BUILD_DIR

# Install build dependencies
cargo install cargo-zigbuild
cargo install cargo-xwin

zig_build () {
    local TARGET="$1"
    local PLATFORM_NAME="$2"
    local LIBNAME="$3"
    rustup target add "$TARGET"
    cargo zigbuild --target "$TARGET" -r
    mkdir "$PLATFORM_NAME"
    cp "../target/$TARGET/release/$LIBNAME" "$PLATFORM_NAME/"
}

win_build () {
    local TARGET="$1"
    local PLATFORM_NAME="$2"
    local LIBNAME="$3"
    rustup target add "$TARGET"
    cargo xwin build --target "$TARGET" -r
    mkdir "$PLATFORM_NAME"
    cp "../target/$TARGET/release/$LIBNAME" "$PLATFORM_NAME/"
}

# Build all the dynamic libraries
LINUX_LIBNAME=liblibrary_name.so
zig_build aarch64-unknown-linux-gnu linux-arm64 $LINUX_LIBNAME
zig_build x86_64-unknown-linux-gnu linux-x64 $LINUX_LIBNAME
WINDOWS_LIBNAME=library_name.dll
win_build aarch64-pc-windows-msvc windows-arm64 $WINDOWS_LIBNAME
win_build x86_64-pc-windows-msvc windows-x64 $WINDOWS_LIBNAME

# Archive the dynamic libs
tar -czvf other.tar.gz linux-* windows-*

# Cleanup
rm -rf linux-* windows-*