Add a way to not use bindgen

Fix tikv#489

Add the `use-bindgen` feature which is activated by default.

If
disabled, then the previously generated bindings will be used instead of
generating new ones. It will fail compilation if this feature is
disabled for the non supported targets.

If enabled, the behaviour is the same as before.

Signed-off-by: Hugues de Valon <[email protected]>

Author: hug-dev

Cargo.toml

@@ -17,7 +17,7 @@ autoexamples = false
 all-features = true
 
 [dependencies]
-grpcio-sys = { path = "grpc-sys", version = "0.7" }
+grpcio-sys = { path = "grpc-sys", version = "0.7", default-features = false }
 libc = "0.2"
 futures = "0.3"
 protobuf = { version = "2.0", optional = true }
@@ -30,7 +30,7 @@ parking_lot = "0.11"
 members = ["proto", "benchmark", "compiler", "interop", "tests-and-examples"]
 
 [features]
-default = ["protobuf-codec", "secure"]
+default = ["protobuf-codec", "secure", "grpcio-sys/use-bindgen"]
 protobuf-codec = ["protobuf"]
 prost-codec = ["prost", "bytes"]
 secure = ["grpcio-sys/secure"]

grpc-sys/Cargo.toml

@@ -53,17 +53,21 @@ openssl-sys = { version = "0.9", optional = true, features = ["vendored"] }
 libz-sys = { version = "1.0.25", features = ["static"] }
 
 [features]
-default = []
+default = ["use-bindgen"]
 secure = []
 openssl = ["secure"]
 openssl-vendored = ["openssl", "openssl-sys"]
 no-omit-frame-pointer = []
+# If this feature is disabled, bindgen will not be used and the previously generated bindings will
+# be compiled instead. This only work for the supported targets and will make compilation fails for
+# the other ones.
+use-bindgen = ["bindgen"]
 
 [build-dependencies]
 cc = "1.0"
 cmake = "0.1"
 pkg-config = "0.3"
 walkdir = "2.2.9"
 # Because of rust-lang/cargo#5237, bindgen should not be upgraded util a minor or major release.
-bindgen = { version = "0.51.0", default-features = false }
+bindgen = { version = "0.51.0", default-features = false, optional = true }
 boringssl-src = "0.1.0"

grpc-sys/build.rs

@@ -265,7 +265,18 @@ fn get_env(name: &str) -> Option<String> {
 
 // Generate the bindings to grpc C-core.
 // Try to disable the generation of platform-related bindings.
-fn bindgen_grpc(mut config: bindgen::Builder, file_path: &PathBuf) {
+#[cfg(feature = "use-bindgen")]
+fn bindgen_grpc(file_path: &PathBuf) {
+    // create a config to generate binding file
+    let mut config = bindgen::Builder::default();
+    if cfg!(feature = "secure") {
+        config = config.clang_arg("-DGRPC_SYS_SECURE");
+    }
+
+    if get_env("CARGO_CFG_TARGET_OS").map_or(false, |s| s == "windows") {
+        config = config.clang_arg("-D _WIN32_WINNT=0x600");
+    }
+
     // Search header files with API interface
     let mut headers = Vec::new();
     for result in WalkDir::new(Path::new("./grpc/include")) {
@@ -329,28 +340,36 @@ fn bindgen_grpc(mut config: bindgen::Builder, file_path: &PathBuf) {
 // Determine if need to update bindings. Supported platforms do not
 // need to be updated by default unless the UPDATE_BIND is specified.
 // Other platforms use bindgen to generate the bindings every time.
-fn config_binding_path(config: bindgen::Builder) {
-    let file_path: PathBuf;
+fn config_binding_path() {
     let target = env::var("TARGET").unwrap();
-    match target.as_str() {
+    let file_path: PathBuf = match target.as_str() {
         "x86_64-unknown-linux-gnu" | "aarch64-unknown-linux-gnu" => {
             // Cargo treats nonexistent files changed, so we only emit the rerun-if-changed
             // directive when we expect the target-specific pre-generated binding file to be
             // present.
             println!("cargo:rerun-if-changed=bindings/{}-bindings.rs", &target);
 
-            file_path = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap())
+            let file_path = PathBuf::from(env::var("CARGO_MANIFEST_DIR").unwrap())
                 .join("bindings")
                 .join(format!("{}-bindings.rs", &target));
-            if env::var("UPDATE_BIND").map(|s| s == "1").unwrap_or(false) {
-                bindgen_grpc(config, &file_path);
+
+            #[cfg(feature = "use-bindgen")]
+            if env::var("UPDATE_BIND").is_ok() {
+                bindgen_grpc(&file_path);
             }
+
+            file_path
         }
         _ => {
-            file_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("grpc-bindings.rs");
-            bindgen_grpc(config, &file_path);
+            let file_path = PathBuf::from(env::var("OUT_DIR").unwrap()).join("grpc-bindings.rs");
+
+            #[cfg(feature = "use-bindgen")]
+            bindgen_grpc(&file_path);
+
+            file_path
         }
     };
+
     println!(
         "cargo:rustc-env=BINDING_PATH={}",
         file_path.to_str().unwrap()
@@ -364,12 +383,9 @@ fn main() {
 
     // create a builder to compile grpc_wrap.cc
     let mut cc = cc::Build::new();
-    // create a config to generate binding file
-    let mut bind_config = bindgen::Builder::default();
 
     let library = if cfg!(feature = "secure") {
         cc.define("GRPC_SYS_SECURE", None);
-        bind_config = bind_config.clang_arg("-DGRPC_SYS_SECURE");
         "grpc"
     } else {
         "grpc_unsecure"
@@ -378,7 +394,6 @@ fn main() {
     if get_env("CARGO_CFG_TARGET_OS").map_or(false, |s| s == "windows") {
         // At lease vista
         cc.define("_WIN32_WINNT", Some("0x600"));
-        bind_config = bind_config.clang_arg("-D _WIN32_WINNT=0x600");
     }
 
     if get_env("GRPCIO_SYS_USE_PKG_CONFIG").map_or(false, |s| s == "1") {
@@ -399,5 +414,5 @@ fn main() {
     cc.warnings_into_errors(true);
     cc.compile("libgrpc_wrap.a");
 
-    config_binding_path(bind_config);
+    config_binding_path();
 }