add homebrew formula for libdave native libraries

Formula/libdave.rb

@@ -0,0 +1,107 @@
+class Libdave < Formula
+  desc "Discord's DAVE library for end-to-end encryption"
+  homepage "https://github.com/discord/libdave"
+  url "https://github.com/discord/libdave/archive/refs/tags/v1.1.1/cpp.tar.gz"
+  sha256 "23827d585a2020e1bfc01f0b999d6db63de6033be38ff43b6e4e3b4067139325"
+  license "MIT"
+  version "1.1.1"
+  revision 1
+  head "https://github.com/discord/libdave.git", branch: "main"
+
+  depends_on "cmake" => :build
+  depends_on "nlohmann-json"
+  depends_on "openssl@3"
+
+  resource "mlspp" do
+    url "https://github.com/cisco/mlspp/archive/1cc50a124a3bc4e143a787ec934280dc70c1034d.tar.gz"
+    sha256 "7a9d6318627e548903bc65c3dc5a4de4a90290983efea9a49af8561ed3f999f5"
+  end
+
+  def rewrite_local_dylib_linkage!
+    dylibs = Dir[lib/"*.dylib"].sort
+    dylib_names = dylibs.map { |path| File.basename(path) }
+
+    dylibs.each do |dylib|
+      system "install_name_tool", "-id", (opt_lib/File.basename(dylib)).to_s, dylib
+    end
+
+    dylibs.each do |dylib|
+      Utils.safe_popen_read("otool", "-L", dylib).lines.drop(1).each do |line|
+        dependency = line.strip.split.first
+        next unless dependency&.start_with?("@rpath/")
+
+        dependency_name = dependency.delete_prefix("@rpath/")
+        next unless dylib_names.include?(dependency_name)
+
+        system "install_name_tool", "-change", dependency, (opt_lib/dependency_name).to_s, dylib
+      end
+    end
+  end
+
+  def post_install
+    rewrite_local_dylib_linkage! if OS.mac?
+  end
+
+  def install
+    prefix_path = [
+      Formula["nlohmann-json"].opt_prefix,
+      Formula["openssl@3"].opt_prefix,
+      prefix,
+    ].join(";")
+
+    resource("mlspp").stage do
+      system "cmake", "-S", ".", "-B", "build",
+        *std_cmake_args,
+        "-DBUILD_SHARED_LIBS=ON",
+        "-DTESTING=OFF",
+        "-DDISABLE_GREASE=ON",
+        "-DMLS_CXX_NAMESPACE=mlspp",
+        "-DCMAKE_PREFIX_PATH=#{prefix_path}",
+        "-DOPENSSL_ROOT_DIR=#{Formula["openssl@3"].opt_prefix}"
+      system "cmake", "--build", "build"
+      system "cmake", "--install", "build"
+    end
+
+    system "cmake", "-S", "cpp", "-B", "build",
+      *std_cmake_args,
+      "-DBUILD_SHARED_LIBS=ON",
+      "-DTESTING=OFF",
+      "-DPERSISTENT_KEYS=OFF",
+      "-DCMAKE_PREFIX_PATH=#{prefix_path}",
+      "-DOPENSSL_ROOT_DIR=#{Formula["openssl@3"].opt_prefix}"
+    system "cmake", "--build", "build"
+    system "cmake", "--install", "build"
+
+    rewrite_local_dylib_linkage! if OS.mac?
+  end
+
+  test do
+    if OS.mac?
+      system "/usr/bin/ruby", "-e", "require 'fiddle'; Fiddle.dlopen(ARGV.fetch(0))", lib/"libdave.dylib"
+    end
+
+    (testpath/"CMakeLists.txt").write <<~CMAKE
+      cmake_minimum_required(VERSION 3.20)
+      project(libdave_smoke LANGUAGES CXX)
+
+      find_package(libdave CONFIG REQUIRED)
+
+      add_executable(libdave_smoke main.cpp)
+      target_link_libraries(libdave_smoke PRIVATE libdave::libdave)
+    CMAKE
+
+    (testpath/"main.cpp").write <<~CPP
+      #include <dave/version.h>
+
+      int main() {
+        return discord::dave::MaxSupportedProtocolVersion() > 0 ? 0 : 1;
+      }
+    CPP
+
+    system "cmake", "-S", ".", "-B", "build",
+      "-DCMAKE_BUILD_TYPE=Release",
+      "-DCMAKE_PREFIX_PATH=#{opt_prefix};#{Formula["openssl@3"].opt_prefix}"
+    system "cmake", "--build", "build"
+    system "./build/libdave_smoke"
+  end
+end

README.md

@@ -4,4 +4,7 @@ This repository contains the JS and C++ libraries which together implement Disco
 
 The DAVE protocol is described in detail in the [protocol whitepaper](https://github.com/discord/dave-protocol).
 
-See the [cpp README](/cpp/README.md) or the [js README](/js/README.md) for information specific to each library.
+The C++ library can be installed on macOS with Homebrew via this repository's
+tap; see the [cpp README](/cpp/README.md) for the tap and install commands.
+
+See the [cpp README](/cpp/README.md) or the [js README](/js/README.md) for information specific to each library.

cpp/CMakeLists.txt

@@ -2,7 +2,7 @@ cmake_minimum_required(VERSION 3.20)
 
 project(
   libdave
-  VERSION 1.0
+  VERSION 1.1.1
   LANGUAGES CXX C
 )
 
@@ -14,7 +14,8 @@ option(ENABLE_SANITIZERS "Enable address and undefined behavior sanitizers" OFF)
 option(INSTALL_VCPKG_LICENSES "Installs license files from vcpkg deps which require it" OFF)
 
 include(CheckCXXCompilerFlag)
-include(CMakeFindDependencyMacro)
+include(CMakePackageConfigHelpers)
+include(GNUInstallDirs)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
@@ -102,9 +103,10 @@ else()
 endif()
 
 find_package(nlohmann_json REQUIRED)
-find_dependency(MLSPP REQUIRED)
+find_package(MLSPP REQUIRED)
 
 set(CMAKE_STATIC_LIBRARY_PREFIX "")
+set(LIBDAVE_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/${PROJECT_NAME}")
 
 SET(LIB_NAME ${PROJECT_NAME})
 file(GLOB_RECURSE LIB_HEADERS CONFIGURE_DEPENDS "${CMAKE_CURRENT_SOURCE_DIR}/src/*.h" "${CMAKE_CURRENT_SOURCE_DIR}/includes/*.h")
@@ -187,22 +189,56 @@ target_include_directories(
   ${LIB_NAME}
   PUBLIC
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/includes>
-    $<INSTALL_INTERFACE:include>
+    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
   PRIVATE
     $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>
 )
 
-target_link_libraries(${LIB_NAME} PRIVATE OpenSSL::Crypto)
-target_link_libraries(${LIB_NAME} PRIVATE MLSPP::mlspp)
+target_link_libraries(${LIB_NAME} PUBLIC OpenSSL::Crypto)
+target_link_libraries(${LIB_NAME} PUBLIC MLSPP::mlspp)
 
 if (APPLE AND PERSISTENT_KEYS)
   target_link_libraries(${LIB_NAME} PUBLIC "-framework CoreFoundation" "-framework Security")
 endif()
 
 set(CMAKE_SKIP_INSTALL_ALL_DEPENDENCY ON)
 
-install(TARGETS ${LIB_NAME} INCLUDES DESTINATION "include")
-install(DIRECTORY ${PROJECT_SOURCE_DIR}/includes/ DESTINATION "include")
+configure_package_config_file(
+  ${CMAKE_CURRENT_SOURCE_DIR}/cmake/libdaveConfig.cmake.in
+  ${CMAKE_CURRENT_BINARY_DIR}/libdaveConfig.cmake
+  INSTALL_DESTINATION ${LIBDAVE_INSTALL_CMAKEDIR}
+)
+
+write_basic_package_version_file(
+  ${CMAKE_CURRENT_BINARY_DIR}/libdaveConfigVersion.cmake
+  VERSION ${PROJECT_VERSION}
+  COMPATIBILITY SameMajorVersion
+)
+
+install(
+  TARGETS ${LIB_NAME}
+  EXPORT libdave-targets
+  ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR}
+  RUNTIME DESTINATION ${CMAKE_INSTALL_BINDIR}
+  INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
+)
+
+install(
+  EXPORT libdave-targets
+  NAMESPACE libdave::
+  FILE libdaveTargets.cmake
+  DESTINATION ${LIBDAVE_INSTALL_CMAKEDIR}
+)
+
+install(
+  FILES
+    ${CMAKE_CURRENT_BINARY_DIR}/libdaveConfig.cmake
+    ${CMAKE_CURRENT_BINARY_DIR}/libdaveConfigVersion.cmake
+  DESTINATION ${LIBDAVE_INSTALL_CMAKEDIR}
+)
+
+install(DIRECTORY ${PROJECT_SOURCE_DIR}/includes/ DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 
 if (INSTALL_VCPKG_LICENSES)
   set(DEPS_NEEDING_LICENSE mlspp nlohmann-json)
@@ -222,4 +258,4 @@ if (INSTALL_VCPKG_LICENSES)
   endforeach()
 endif()
 
-install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/../LICENSE DESTINATION "licenses" RENAME ${LIB_NAME})
+install(FILES ${CMAKE_CURRENT_SOURCE_DIR}/../LICENSE DESTINATION "licenses" RENAME ${LIB_NAME})

cpp/README.md

@@ -40,6 +40,28 @@ make cclean
 make shared
 ```
 
+### Homebrew (macOS)
+
+Homebrew requires formulae to be installed from a tap. Because this repository
+is named `discord/libdave` rather than `discord/homebrew-libdave`, tap it with
+an explicit URL first:
+```
+brew tap discord/libdave https://github.com/discord/libdave
+brew install --build-from-source discord/libdave/libdave
+```
+
+To install the latest repository head instead of the latest tagged release referenced by the formula, run:
+```
+brew tap discord/libdave https://github.com/discord/libdave
+brew install --build-from-source --HEAD discord/libdave/libdave
+```
+
+The Homebrew install exports a CMake package, so downstream projects can consume libdave with:
+```
+find_package(libdave CONFIG REQUIRED)
+target_link_libraries(your_target PRIVATE libdave::libdave)
+```
+
 ### SSL
 
-By default the library builds with OpenSSL 3, however you can modify `VCPKG_MANIFEST_DIR` in the [Makefile](Makefile) to build with OpenSSL 1.1 or BoringSSL instead.
+By default the library builds with OpenSSL 3, however you can modify `VCPKG_MANIFEST_DIR` in the [Makefile](Makefile) to build with OpenSSL 1.1 or BoringSSL instead.

cpp/cmake/libdaveConfig.cmake.in

@@ -0,0 +1,10 @@
+@PACKAGE_INIT@
+
+include(CMakeFindDependencyMacro)
+
+find_dependency(OpenSSL REQUIRED)
+find_dependency(MLSPP REQUIRED)
+
+include("${CMAKE_CURRENT_LIST_DIR}/libdaveTargets.cmake")
+
+check_required_components(libdave)