Add option to link statically against GNUStep's libobjc2

libobjc2_src/src/lib.rs

@@ -11,62 +11,101 @@ need to fetch the submodule's contents from
 https://github.com/gnustep/libobjc2
 "#;
 
-#[non_exhaustive]
-pub enum LibKind {
-    Dynamic,
-    Static,
-    // Framework,
-}
-
-pub struct Artifacts {
-    include_dir: PathBuf,
-    lib_dir: PathBuf,
+pub struct Builder {
     lib_kind: LibKind,
-    lib_name: &'static str,
+    objcxx: bool,
 }
 
-pub fn build() -> Artifacts {
-    // GNUStep only compiles with clang, so try that first.
-    // (But let the user specify a different path if they need to).
-    if env::var_os("CC").is_none() {
-        env::set_var("CC", "clang");
+impl Builder {
+    pub fn new() -> Self {
+        Self {
+            lib_kind: LibKind::Dynamic,
+            objcxx: true,
+        }
     }
-    if env::var_os("CXX").is_none() {
-        env::set_var("CXX", "clang++");
+
+    /// Set the type of library to be built, and how linking is performed.
+    ///
+    /// Possible options are [`LibKind::Static`] and [`LibKind::Dynamic`].
+    ///
+    /// Defaults to [`LibKind::Dynamic`].
+    pub fn lib_kind(&mut self, kind: LibKind) -> &mut Self {
+        self.lib_kind = kind;
+        self
     }
 
-    let source_dir = Path::new(env!("CARGO_MANIFEST_DIR")).join("libobjc2");
-    if !source_dir.join("objc/objc.h").exists() {
-        panic!("{}", NO_SOURCES_MSG);
+    /// Enable support for Objective-C++.
+    ///
+    /// Namely interoperability between Objective-C and C++ exceptions.
+    ///
+    /// Defaults to [`true`].
+    pub fn objcxx(&mut self, objcxx: bool) -> &mut Self {
+        self.objcxx = objcxx;
+        self
     }
 
-    let dst = cmake::Config::new(source_dir)
-        // Default to ignoring `gnustep-config` presence, since they usually
-        // want to install the libraries globally (which requires root).
-        // Users that want systemwide installation should just install it
-        // themselves, and shouldn't need to vendor GNUStep.
-        .define("GNUSTEP_INSTALL_TYPE", "NONE")
-        .define("BUILD_STATIC_LIBOBJC", "OFF") // Default
-        .define("DEBUG_ARC_COMPAT", "OFF") // Default
-        .define("ENABLE_OBJCXX", "ON") // Default (NO_OBJCXX in code)
-        .define("ENABLE_TRACING", "OFF") // Default (WITH_TRACING in code)
-        .define("LEGACY_COMPAT", "OFF") // Default (NO_LEGACY in code)
-        // .define("OLDABI_COMPAT", "?") // Default depends on WIN32
-        .define("TESTS", "OFF")
-        .define("TYPE_DEPENDENT_DISPATCH", "ON") // Default
-        // .always_configure(false) // TODO
-        // .static_crt(?)
-        .build_target("install")
-        .build();
-
-    Artifacts {
-        include_dir: dst.join("include"),
-        lib_dir: dst.join("lib"),
-        lib_kind: LibKind::Dynamic,
-        lib_name: "objc",
+    pub fn build(&mut self) -> Artifacts {
+        // GNUStep only compiles with clang, so try that first.
+        // (But let the user specify a different path if they need to).
+        if env::var_os("CC").is_none() {
+            env::set_var("CC", "clang");
+        }
+        if env::var_os("CXX").is_none() {
+            env::set_var("CXX", "clang++");
+        }
+
+        let source_dir = Path::new(env!("CARGO_MANIFEST_DIR")).join("libobjc2");
+        if !source_dir.join("objc/objc.h").exists() {
+            panic!("{}", NO_SOURCES_MSG);
+        }
+
+        let dst = cmake::Config::new(source_dir)
+            // Default to ignoring `gnustep-config` presence, since they
+            // usually want to install the libraries globally (which requires
+            // root). Users that want systemwide installation should just
+            // install it themselves, and shouldn't need to vendor GNUStep.
+            .define("GNUSTEP_INSTALL_TYPE", "NONE")
+            // Don't bother building tests, we're not gonna run them anyways
+            // (and they're not available when packaged, see Cargo.toml).
+            .define("TESTS", "OFF")
+            // Having this on also builds the dynamic library, but not really
+            // anything we can do to change that.
+            .define(
+                "BUILD_STATIC_LIBOBJC",
+                match self.lib_kind {
+                    LibKind::Static => "ON",
+                    LibKind::Dynamic => "OFF",
+                },
+            )
+            .define("ENABLE_OBJCXX", if self.objcxx { "ON" } else { "OFF" })
+            // Various other defaults
+            // .define("OLDABI_COMPAT", "ON")
+            // .define("DEBUG_ARC_COMPAT", "OFF")
+            // .define("ENABLE_TRACING", "OFF")
+            // .define("LEGACY_COMPAT", "OFF")
+            // .define("LIBOBJC_NAME", "objc")
+            // .define("TYPE_DEPENDENT_DISPATCH", "ON")
+            // .define("STRICT_APPLE_COMPATIBILITY", "0") // Default none
+            // TODO: .static_crt(?)
+            .build_target("install")
+            .build();
+
+        Artifacts {
+            include_dir: dst.join("include"),
+            lib_dir: dst.join("lib"),
+            lib_kind: self.lib_kind,
+            lib_name: "objc",
+        }
     }
 }
 
+pub struct Artifacts {
+    include_dir: PathBuf,
+    lib_dir: PathBuf,
+    lib_kind: LibKind,
+    lib_name: &'static str,
+}
+
 impl Artifacts {
     pub fn include_dir(&self) -> &Path {
         &self.include_dir
@@ -76,8 +115,8 @@ impl Artifacts {
         &self.lib_dir
     }
 
-    pub fn lib_kind(&self) -> &LibKind {
-        &self.lib_kind
+    pub fn lib_kind(&self) -> LibKind {
+        self.lib_kind
     }
 
     pub fn lib_name(&self) -> &str {
@@ -86,7 +125,7 @@ impl Artifacts {
 
     pub fn print_cargo_metadata(&self) {
         let kind = match self.lib_kind {
-            LibKind::Dynamic => "dynamic",
+            LibKind::Dynamic => "dylib",
             LibKind::Static => "static",
         };
         println!("cargo:rustc-link-search=native={}", self.lib_dir.display());
@@ -95,3 +134,11 @@ impl Artifacts {
         println!("cargo:lib={}", self.lib_dir.display());
     }
 }
+
+#[non_exhaustive]
+#[derive(Clone, Copy)]
+pub enum LibKind {
+    Dynamic,
+    Static,
+    // Framework,
+}

objc2_sys/Cargo.toml

@@ -29,8 +29,13 @@ links = "objc"
 build = "build.rs"
 
 [features]
-# If enabled, GNUStep's libobjc2 will be compiled and linked from source
+# If enabled, GNUStep's libobjc2 will be compiled and linked from source.
 vendor_gnustep = ["libobjc2_src"]
+# Whether to link to libobjc statically.
+#
+# Only supported for vendored dependencies, it will trigger a compile-time
+# error when venoring is not enabled.
+static = []
 
 [build-dependencies]
 libobjc2_src = { path = "../libobjc2_src", optional = true }

objc2_sys/build.rs

@@ -1,12 +1,24 @@
 #[cfg(feature = "vendor_gnustep")]
 fn main() {
-    let artifacts = libobjc2_src::build();
+    let mut builder = libobjc2_src::Builder::new();
+
+    #[cfg(feature = "static")]
+    builder.lib_kind(libobjc2_src::LibKind::Static);
+    #[cfg(not(feature = "static"))]
+    builder.lib_kind(libobjc2_src::LibKind::Dynamic);
+
+    let artifacts = builder.build();
     artifacts.print_cargo_metadata();
+
+    // Add #[cfg(gnustep)] directive
     println!("cargo:rustc-cfg=gnustep");
 }
 
 #[cfg(not(feature = "vendor_gnustep"))]
 fn main() {
+    #[cfg(feature = "static")]
+    compile_error!("Can only link statically to libobjc when vendoring is enabled.");
+
     // Only rerun if this file changes; the script doesn't depend on our code
     println!("cargo:rerun-if-changed=build.rs");