Support cc as an optional alternative to cmake

.github/workflows/ci.yml

@@ -79,6 +79,27 @@ jobs:
         target:
           - x86_64-apple-darwin
 
+  cc:
+    runs-on: ubuntu-22.04
+    env:
+      TARGET_TRIPLE: x86_64-unknown-linux-gnu
+    steps:
+      - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          submodules: true
+      # Ensures --all-features builds correctly, the current logic will mean it
+      # uses stock zlib, not cmake nor cc
+      - run: |
+          cargo test --target $TARGET_TRIPLE --all-features
+          cargo run --target $TARGET_TRIPLE --manifest-path systest/Cargo.toml --all-features
+      # Ensures zlib-ng builds and runs, though zlib-ng _could_ change internally
+      # and not use all optimizations available to the CI runner, we do this here
+      # just for x86_64-unknown-linux-gnu to validate a common target compiles
+      # on a more recent compiler than the incredibly ancient one currently used by cross
+      - run: |
+          cargo test --target $TARGET_TRIPLE --no-default-features --features zlib-ng-no-cmake-experimental-community-maintained || echo "::warning::failed to build libz-ng with --features zlib-ng-no-cmake-experimental-community-maintained"
+          cargo run --target $TARGET_TRIPLE --manifest-path systest/Cargo.toml --no-default-features --features zlib-ng-no-cmake-experimental-community-maintained || echo "::warning::failed to run systest with --features zlib-ng-no-cmake-experimental-community-maintained"
+
   linux:
     runs-on: ubuntu-latest
     needs: install-cross

Cargo-zng.toml

@@ -1,7 +1,11 @@
 [package]
 name = "libz-ng-sys"
 version = "1.1.15"
-authors = ["Alex Crichton <alex@alexcrichton.com>", "Josh Triplett <josh@joshtriplett.org>", "Sebastian Thiel <sebastian.thiel@icloud.com>"]
+authors = [
+    "Alex Crichton <alex@alexcrichton.com>",
+    "Josh Triplett <josh@joshtriplett.org>",
+    "Sebastian Thiel <sebastian.thiel@icloud.com>",
+]
 links = "z-ng"
 license = "MIT OR Apache-2.0"
 repository = "https://github.com/rust-lang/libz-sys"
@@ -22,7 +26,7 @@ exclude = [
     "/systest",
 ]
 
-build = "build_zng.rs"
+build = "zng/cmake.rs"
 readme = "README-zng.md"
 
 [workspace]
@@ -32,4 +36,4 @@ members = ["systest"]
 libc = "0.2.43"
 
 [build-dependencies]
-cmake = "0.1.44"
+cmake = "0.1"

Cargo.toml

@@ -34,7 +34,7 @@ libc = { version = "0.2.43", optional = true }
 [build-dependencies]
 pkg-config = "0.3.9"
 cc = "1.0.18"
-cmake = { version = "0.1.44", optional = true }
+cmake = { version = "0.1.50", optional = true }
 vcpkg = "0.2"
 
 [features]
@@ -56,9 +56,14 @@ default = ["libc", "stock-zlib"]
 #
 # This allows higher-level crates depending on your library to opt into zlib-ng
 # if desired.
+zlib-ng = ["libc", "cmake"]
+# Builds zlib-ng from source using cc instead of cmake with all target features
+# enabled, meaning compilation may not work depending on your target and host
+# toolchain (eg very old compilers won't have some flags)
 #
-# Building zlib-ng requires cmake.
-zlib-ng =  ["libc", "cmake"]
+# This feature is not maintained by the repo maintainers and can break at any time
+# or be completely removed in the future
+zlib-ng-no-cmake-experimental-community-maintained = ["libc"]
 stock-zlib = []
 # Deprecated: the assembly routines are outdated, and either reduce performance
 # or cause segfaults.

README.md

@@ -43,7 +43,11 @@ libz-sys = { version = "1.1", default-features = false, features = ["libc"] }
 This allows higher-level crates depending on your library to opt into zlib-ng
 if desired.
 
-Building zlib-ng requires `cmake`.
+Building zlib-ng requires `cmake` unless the
+`zlib-ng-no-cmake-experimental-community-maintained` feature is enabled,
+in which case `cc` is used instead. Note that this option enables _all_ compiler
+features that are supported for the given target, which may not compile on older
+compilers or targets without certain headers.
 
 Crates that don't require compatibility with the zlib C API, and use zlib
 exclusively from Rust or support the zlib-ng native C API (prefixed with
@@ -62,10 +66,10 @@ but we don't guarantee these will continue to work.
 
 This project is licensed under either of
 
- * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
-   https://www.apache.org/licenses/LICENSE-2.0)
- * MIT license ([LICENSE-MIT](LICENSE-MIT) or
-   https://opensource.org/license/mit/)
+* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+   <https://www.apache.org/licenses/LICENSE-2.0>)
+* MIT license ([LICENSE-MIT](LICENSE-MIT) or
+   <https://opensource.org/license/mit/>)
 
 at your option.
 

build.rs

@@ -5,12 +5,18 @@ use std::path::PathBuf;
 fn main() {
     println!("cargo:rerun-if-env-changed=LIBZ_SYS_STATIC");
     println!("cargo:rerun-if-changed=build.rs");
+    println!("cargo:rerun-if-changed=zng/cmake.rs");
+    println!("cargo:rerun-if-changed=zng/cc.rs");
+
     let host = env::var("HOST").unwrap();
     let target = env::var("TARGET").unwrap();
 
     let host_and_target_contain = |s| host.contains(s) && target.contains(s);
 
-    let want_ng = cfg!(feature = "zlib-ng") && !cfg!(feature = "stock-zlib");
+    let want_ng = cfg!(any(
+        feature = "zlib-ng",
+        feature = "zlib-ng-no-cmake-experimental-community-maintained"
+    )) && !cfg!(feature = "stock-zlib");
 
     if want_ng && target != "wasm32-unknown-unknown" {
         return build_zlib_ng(&target, true);
@@ -169,13 +175,31 @@ fn build_zlib(cfg: &mut cc::Build, target: &str) {
     println!("cargo:include={}/include", dst.to_str().unwrap());
 }
 
-#[cfg(not(feature = "zlib-ng"))]
-fn build_zlib_ng(_target: &str, _compat: bool) {}
+#[cfg(any(
+    feature = "zlib-ng",
+    feature = "zlib-ng-no-cmake-experimental-community-maintained"
+))]
+mod zng {
+    #[cfg_attr(feature = "zlib-ng", path = "cmake.rs")]
+    #[cfg_attr(
+        all(
+            feature = "zlib-ng-no-cmake-experimental-community-maintained",
+            not(feature = "zlib-ng")
+        ),
+        path = "cc.rs"
+    )]
+    mod build_zng;
+
+    pub(super) use build_zng::build_zlib_ng;
+}
 
-#[cfg(feature = "zlib-ng")]
-mod build_zng;
-#[cfg(feature = "zlib-ng")]
-use build_zng::build_zlib_ng;
+fn build_zlib_ng(_target: &str, _compat: bool) {
+    #[cfg(any(
+        feature = "zlib-ng",
+        feature = "zlib-ng-no-cmake-experimental-community-maintained"
+    ))]
+    zng::build_zlib_ng(_target, _compat);
+}
 
 fn try_vcpkg() -> bool {
     // see if there is a vcpkg tree with zlib installed

ci/test.bash

@@ -31,16 +31,32 @@ fi
 
 $CROSS test --target $TARGET_TRIPLE
 $CROSS run --target $TARGET_TRIPLE --manifest-path systest/Cargo.toml
-echo === zlib-ng build ===
+
+echo '::group::=== zlib-ng build ==='
 $CROSS test --target $TARGET_TRIPLE --no-default-features --features zlib-ng
 $CROSS run --target $TARGET_TRIPLE --manifest-path systest/Cargo.toml --no-default-features --features zlib-ng
-echo === libz-ng-sys build ===
+echo '::endgroup::'
+
+# Note we skip compiling these targets on CI because the gcc version currently used in
+# cross for them is 5.4, ~8 years old at this point, hopefully it will be updated...sometime
+skip_triples=("x86_64-unknown-linux-gnu" "i686-unknown-linux-gnu" "aarch64-unknown-linux-gnu" "arm-unknown-linux-gnueabihf" "s390x-unknown-linux-gnu")
+if [[ -z $CI ]] || ! [[ ${skip_triples[@]} =~ "${TARGET_TRIPLE}" ]]; then
+    echo '::group::=== zlib-ng-no-cmake-experimental-community-maintained build ==='
+
+    $CROSS test --target "$TARGET_TRIPLE" --no-default-features --features zlib-ng-no-cmake-experimental-community-maintained || echo "::warning file=$(basename $0),line=$LINENO::Failed to test zlib-ng with --features zlib-ng-no-cmake-experimental-community-maintained"
+    $CROSS run --target "$TARGET_TRIPLE" --manifest-path systest/Cargo.toml --no-default-features --features zlib-ng-no-cmake-experimental-community-maintained || echo "::warning file=$(basename $0),line=$LINENO::Failed to run systest with --features zlib-ng-no-cmake-experimental-community-maintained"
+
+    echo '::endgroup::'
+fi
+
+echo '::group::=== libz-ng-sys build ==='
 mv Cargo-zng.toml Cargo.toml
 mv systest/Cargo-zng.toml systest/Cargo.toml
 $CROSS test --target $TARGET_TRIPLE
 $CROSS run --target $TARGET_TRIPLE --manifest-path systest/Cargo.toml
+echo '::endgroup::'
 
-echo === flate2 validation ===
+echo '::group::=== flate2 validation ==='
 git clone https://github.com/rust-lang/flate2-rs flate2
 git worktree add flate2/libz-sys
 git worktree add flate2/libz-ng-sys
@@ -67,4 +83,5 @@ set -x
 $CROSS test --features zlib --target $TARGET_TRIPLE
 $CROSS test --features zlib-default --no-default-features --target $TARGET_TRIPLE
 $CROSS test --features zlib-ng --no-default-features --target $TARGET_TRIPLE
-$CROSS test --features zlib-ng-compat --no-default-features --target $TARGET_TRIPLE
+$CROSS test --features zlib-ng-compat --no-default-features --target $TARGET_TRIPLE
+echo '::endgroup::'

systest/Cargo.toml

@@ -14,3 +14,6 @@ ctest2 = "0.4.4"
 [features]
 libz-static = ["libz-sys/static"]
 zlib-ng = ["libz-sys/zlib-ng"]
+zlib-ng-no-cmake-experimental-community-maintained = [
+    "libz-sys/zlib-ng-no-cmake-experimental-community-maintained",
+]